Note: Descriptions are shown in the official language in which they were submitted.
r~ ~
Z~52M 35679
A Resin Bound Magnet And Its Production Process
Th1~ lnv~neiQn r~l~t~6 to a r-~ln ~oun~ ~ype maqnot whleh 16 u~-d ~or a
mln~atura motor, an ~nco~r, a lino~r ac~uator, Qtc. whlch are appll~
~or el2ctronics- in-trument~, ~tc. and lt6 productlon prOCQ6, e~p~cially
~or a cylindrical or a thln plat~ resln boun~ type ma~net, ~nd it~
production p~ocess by u61ng an extru~lon mouldin~ ~thod.
The re~l~ boun~ type masnet 1~ ~eneraliy pro~uced by ~1~ an ~n~ec~:cn
mouidlng method, (2) a pre6~ mouldl~g m~t~od and (3) an extru6lc~
mouldlng proces~.
Among thQce moulding method~, th~ in~ec~ion mouldlng m~thod 1~ to mo~ld a
pr~d~t~rmine~ ~hcpe ~y paohlng a ma~n~t eompoaition compr~lng ~ m~gnetlc
powd~r and thormopla~tlc rs~ln lnto a d~e ~y ho~tln~ lt at
t~mp~ratu~e ~t wh$oh a ~u~cl~nt ~lu$~ity 1~ ~ttainod~
~e pre-~ mouldln~ m~t~o~L 1B A tnoul~lng m-tho~ by p~ ing afte~ ~acl~ng
~ m~ t ~o~po~tlon eomprl~ a msg~etlc pow~r ~n~ 4 thel~ o-Q'Ct~
15 r~ln lnto a die of ~ pr~ mae~lno.
~ 1 --
.. , . , . ~ .
2 ~ '~ ~! ''` ~i ''
The extru6ion mouldln~ mQthod 1~ ~ ~oul~ln~ ~e~h~d by ch~rqln~ a ma~rietlc
compo~tlon ln A flul~lz~d ct~te by ~eatln~ a mlxturo of ~ mægn~tlC
po~aer ant a re~in to ~A~e lt ln a ~olten ~at~ by a ~cr~w, a ram or
plunger lnto a di-, and. by conver~ n~ ~ t there .
Among the6e moul~n~ m~thod~, the iniection ~oul~ing and the pre66
moul~lng can ~ould a magn~t havin~ an a~lgotropy by apply~ng a ma~netlc
1eld ln the dle At th~ moul~lng ~tep. ~ow~v~r ~ for the in~ectlon
mouldln~ method snd 3 proo~ mould~ng metho~ ~or a ~ouldlng of a lonq
sl20d magnet of which d~m~n~ i~ rec~ntly belng ~ncroa~d, in ca~e of the
in~ectlon ~oul~ing method ~ecau~e o~ an lmpo~6~iilty of ~sck~ng o a
magnet compo~ltion in a cavlty ~nd of taking out ~ mouldQd artlcle, etc
and ln ca6e o~ the Pre~S moul~ng me~hod 6ince a lQn~th o~ a moul~ed
~rtlc;e i~ determlned by a Etroke of a mouldlng punc~, they have a defec~
that the len~th o~ the moulded article 16 limited. E6peclally ~n ca~e cf
a mouldlng o~ a cylindrical ~agnet havins a radiated ~nlsotropy, there 16
a llmitation on the le~th ~ the mou;~e~ articl~, an~ ~ maqne~, o~ which
an outerdlat-r (herelna~tQr called a~ D), an lnner ~ia~-t~r (herelnaftQr
cell~d a~ ~) and a lcn~th ~h~rQinafter callod a~ L) satl~fy
below~ ted ~uatlon, c~n only be ~ould~d.
2D~ / d2 c ~
(~e~er-nce llteratur~. Ma~ Hamano, an ab~tract book on the 9~h
~sting of Sn~ectlon MoUl~lng T~chnolosy o ~gh P~r~or~anc~ Pla6tic
Ma6net ~d It~ A~pllcatio~ DQv~lop~nt, P1A9~iC In~u~trY Techni~l
Com~ltt~e 19 6 )
,
. .
. . .
Accordlngly a~ to a cylindrlcal ma~net which 8ati~ie6
~DL ~ d2 ~, 1,
only 2 kind~ w~re obtainable 1~ on~ wa~ a ~n~le ~oulaa~ mAgndt Wlth an
i~otropy o~ w~th a poor magn~t p~ormanc~ ~nd the oth-r waE a one whlch
5 wa6 prepared ~Y ~tlckln~ plural nun~ber of th-~ magnet~ hevin~ a radl a ed
an i s ot ropy .
~owever the afor~mantloned cyl~n~r~cal re~ln bound type m~net ~nd 1
productlon proce~ have problom~ lls~2d ~elow,
t 1 ) In order to get a hlgh per~orman~e motor or an a~tu~tor by u~l~g an
10 i60tropiC ~,agnet or a ma~net having a performance clo~e to the l~otroplc
. .
maSnet, the volume of the ~agnet to be used ha6 to ~e large, ~l~d a
miniaturl~atlon and a llght weighin~ o~ the6e in6~rument6 can n~t be
s~t~sf.ed.
t 2 ) In case that plural numb~r o~ th~ ma~nets havlng a r~dlcate~
15 anisotropy i6 6tuck, th~re are followin~ prcblem6.
[1~ ~he tlcklnq ~ w~a~ a~a~ t delam~natlon ~nd there is a dan~er
of destroying tho bo~ by a r~p~at-~ hot ~nd cold cycle. It has an
in~erlor rell~llity ~uch ~ a v~rlation o~ the ~tlchlng ctr6noth,
- etc.
C2~ A productlon co~t ~ r~ b~cau~Q o~ a ~t-~ o~ the ctlc~ln~ ln
a pro~uctlo~ p~oc~. Furth~rmore the ~tuck ~gnot h~ to ~e
; flni~hQd by ~ cut~ln~ f~r~c-tlon, ~tc ~o ~n~u~e fi dimQnsion~
- 3 -
,. .
. , .
, ~ .
:.' ,
: . : ; , .
,, , : - .
: . . :, ; :
. ' ''' ''.' '' ' ' ~ '
:: : ,
i :, , : ~
2 ~
accuracy of the ~oulded ~rt~cle ra~ulti~ a ~urCh~r l~crQ~ of the
productlon co~t.
; [3] In c~e of the flnl~h by the GU~tl~ ~ab~lcat~on of tho mould~d
artlcle, there i~ a pO~ ty of a de~rlor~tlon of the ~agnQt
performance by the flnl~h.
(3) A~ for the in~ctio~ moulding me~ho~ and ~he pr~ ould~n~ method,
it rQ~ulree ~ ~lxe~ cycl~ of a packin~, ~ mouldlng an~ ~ ~ak~ng out of a
magnet compo~itlon to/from a dle ~n the mo~ldlng ~rocR~ nd the
productivity 16 limited b~cau~e it 1B baElcall~ a batch typ~ produc~ion
o ey5tem. ~t is, therefore, dlflcult to achlev~ ~ r~uctior. of the
production c06t.
(4) A~ for the conventional ~xtru~lon mouldinq method, lt 1~ ~ajo-
method not to apply ~ maqnetlc f~el~ at the mouldln~ ~tage. ~owever ~n
i60troplo magnet can only be att~lned by t~l6 mo~ln~ mhthod.
Accordingly the extruEion mouldlng m~thod, whlch ha~ ~ vory ~gh
product~lty dua to an sb~llty of a contlnuou~ opora~lon ~rom a ~up~ly of
a raw ~t~risl to ~ r~91pt 0~ ~ ~auldQA ~rtlclQ, snd 18 hbl- to Q~lly
mould B long ~iz~d ma~n~t, b-com~ popul~r. P~rt$cul~1y th~r~ are many
ro~o~rchq~ to lmprove th~ magn~t p~orm~nc-, e~pocl~lly r-s~rchoc ~n ~n
extrwlon ~oula~n~ ~thod ln a m~gnotlc fl~ld ~n ort-r to roform thc
m~qnQtlc p~o~rty which h~- b0~n con~l~Qrad to b~ poor.
"
., .
~ - 4 -
'' '
.
,. - : ~ .
;
:: :
2 ~,~ J i,L ,, ~"~
~oncerning a mothod to charge a m~gnQ~1c fleld ~t th~ mouldln~ ~tep, as
_or a colu~n typ~ m~net, there lc a r~port by ~.~. John~on ~'D~v~loP~er~-
ln The ProdUction of Bond~d Rare E~rth-Cobalt Ma~net~ th Int~rnational
wo~hop on Rare ~arth-Cobalt Ma~n~t~ ~nd ~helr ~ppllcatlon~, 1981~, an~
a~ for a cyll~drlcal m~gnet, th~rQ ar~ ~thod6 ~hown ln J~pan Pat~..t
Lald-Open ~ho 5a-219705 and J~pan Pat~nt ~id-O~en Sho 61-121307.
Bo~h of the~e ~ethods were to form a m~gnet by orien~atin~ an ~nlx o'
ea6y magnetiza~lon of a magnetlc pow~e~ to a dlrectlon of o magnQt:c
~leld by cha~çln~ ~ ma~netlc fleld ln ~ dle of ~n Qxtru6lon machlne wh~le
a ma~net compo~ltior. wa~ belns pas~e~ througb the ~e, However ~c-
example in a method de~cribed ln ~apan Patent Lald-Opan Sho 61-121307,
cylindrical magnet ma~ne~ized and orlentated ln a dle wa~ coolo~ ~y a
cooling unlt out~i~e the die, a d~rection of the anl~otropy wa6 only
for~ed in one directlon and a moulded article havlng a rad~tQ~
ani~otroPY ln a diameter direction co~l~ not be obtalnod. Moreover, when
the mGulded article was ext~ded from the die, it6 temperature wa~ ~t~;l
hlgh resultln~ a d~tQrloration of ~ ma~n~t p-r~ormahce by ~ dl~ord~r of
an orientation of a ma~netic po~der. A~ a re~ult~, it 1~ not attain~ble
to set a cyl~ndrlcal ~a~n~t havin~ a high ma~nQt perform~nc~ radl~tsd
anl~otroPY evon lf thl~ ~etho~ 1~ appll-d.
:,
~or~ov~r ther- arQ ~olow~ t~ probl-m~ in the ~for~ont~on~d productlon
~ethod.
., ,
n th- oonvQntl~nal xtru8ion moul~ln~ method ln a ma~n~tlc fleld, a
-ctrom~tn~tlc co~ m-rely lnot~ on th~ ~ie and no con~lder~tlon
-. .
. - :
-. ,
' "'' ' ~ ' :
: ~ . . .
2 ~
ic pald ~or a demaanetl~at,orl of a rnoul~Qd artlcle pro~uc@d. If there 1~
a residual r,~netl~m in a moul~d articlQ, lt 1~ v~!ry dl~f lcult to handle
~n the po~t proce~ ~UCh a~ an a~he~ion a~ a cut ota~ to a cuttQr or
othe~ magneti c materlala . F~lrther ~hen a pr-d~lt~rmin~d magn-tlzatlon i8
5 carrie~ ou~ for th~ magn~t, th- r~itu~ gn~tl~m g~v~ 6n unfavorable
inf lue~e to a balance of the magnetization.
~2) AC an exampla of ~ ~nouldlng rn~thod ln which th~ ~omacnet~zatlon o~
the extrusion moulded ~rt~cle ~ considered i~ dl~ClOCQt ln Japan P~tent
Lald-Open Sho 60-217617, ~owever ~ince the demsgnetizatlon col.l i~
10 Qquipped at a front end cf a ~i~ ln ~hi~ caQe, lt recult~ an extr~melY
large dle and a mouldabllity 16 poor. Especially ~ince a pa~baqe of A
r~w materlal co~po~nd ls~ t~e dl~ 1E long, the moulding 6paec ~ ~ clow a..
the moulding i~elf 1~ al60 difflcult.
(3) When a cylindr~cal magnet havlng a ~adiated anl~otropy l~ moul~ec, ~
15 length of an oriontation ~ectlon on which a ma~notic ~l~ld 1~ ch~rged due
to a con~tltution of a n~agr,etic clrcult i~ d-t~!r~lned by ~n inner
dl~meter of the moulded artlcl-. However ~lnce a con~ erably hlgh
m~gnetlc lield 1~ ~n-rally ro~ulr~ to oriQntate a rar~ earth m~gnet
p~wter, the l~n~th o thQ or1-ntatlon hac to b~ ralatlv~ly ~hos~t ln or~er
20 to eharge ~ ~u~lcl~nt ~agn-~lc f ~ R'C the orl-nteltlon ~ection .
Conl~ot~uentlY lt 1~ ntl~lly not ~l- 'co mo~lld a cylln~rlcal magnet
w~lth ~ hl~h maon~t ~Qr~ormance h~vlng a ~ ll inn-r d.lcmoter.
~43 When a eolumn type o~ a rh~-t ~lrP~ mould~, th~ l~no'ch of
the orlcnt~'clon ~oction ~an ~o ~a~- long ~.n a c~r'ca~n ~ogr-e. However a
.` - 6 -
:
~' ,
~ ,,
i - .. . .
- ,
, .. . ..
gap between pole pl~CQC can not ~ m~de too ~hort ~u~ to a mec~anical
~trength o~ the dle, and thus lt 1~ not ~ble ~o lncr~a~o a magnet~c ~leld
to be char~ed at the oriantation too hl~h, ~h~ ~agn~t p~ro~mance of the
moulde~ artlcle therefor~ drop6.
In ca~e that a thermopla¢t~c r~ u~e~ ~6 ~ re~in ln thea~orementlonad ~xtru~lon moul~ln~ ~ethod, thQ moul~in~ 1~ c~rr~od out by
a 6cl~dlflc-tion wlth cooi~ng o a mol~Qn mlxture after orlen~ating at
the front end of thQ dle. when a the~mo~Qttln~ reEln is uc~d ~ a resin,
there are methods to ~ould ~y a solidl~ic~lon wlth coolln~ dfter
orientatin~ at th~ front end of the ~le as same to the ther~opla~tic
reein, and to mould ~ a curlng wlth heatln~ a~ter ~he orien~-ating.
:. .
Ie ca6e of a methcd wit~, t~e ~olldiflcat~on wlth cooling by using the
thermo~ettins resln, it i~ nece~ary to heat lt ~o cure the re~in ~ter
t~e moulding, Anyhcw even lc the mouldlng i6 done by eltheL^ me'ho~s, a
m~gnet moulded l~ ex~rudod -ontlnuou~ly, Qnd lt 14 ~ecess~ry to cut the
magnet moulded ln a pre~etermined l~ngth. For the cut, mechan~cal
cuttlng method- namely a guillotlne cutt-r cy~t~m or ~ rotary ~aw-tooth
.~ ~yet-m wer~ utllized in the conv~ntlon~l m~tho~.
,
~ owever- th- conventlon~l cuttlng matho~ h~d bQlow~ to~ probl-ms.
`
~n ca~e of a m~Ghan~ cal cu tln~ metho~ 6~ch ~ th~ guillotlno cu~ter
~y~tem or the rotary ~aw-~ooth oy~tQm, ~ force an~ a vl~rat~on ~re
char~ to a maCn~t to bc cut. W~en An uncurQ~ r-0~n ~oun~ type magn-t
~oullc~ by a 6011~1~io~tlon w1th coollng by u~1n~ ~ th-r~osett1ng re~n
:
: - .
,
: ~ ~ . . .:
. , , - ., .
, : . . , .: ` :~,
2 ~
is cut and ~ ~hln ~h~ckne~ ma~n-t ch~rset~riz~d bY ~n ~t~u610n mould~nq
lfi cut, a crack, a breaka~e ~d/or a ~form~tlon o~ the ma~net ~re ~a~er
place durlng th~ cut~lnc ~cau6e of ~ brittl~n-s~ an~ a wo~kno~ of th~
magnet to be cut
S ~art~cularly When a volum~ ratlo o~ ~he ~gnetlc powder ln ~ re~in bound
type ma~n~t 1~ lncr~a~ed ln ordor to im~ro~e a perform~ncQ o~ ~he m gnet,
the volume ratlo of th~ ~e~ln ~Rcr~a~ee ~n~ ~he afor~-ntloned pro~lems
tend~ to hapPen ~urther 0~611y bQc~use of ~ r~duct~on o~ bondln~ force of
the res~n with the ~a~ne~c pow~or Mor~ovGr ln ca~ o the mechenlc~l
cut~ing method, a cut du6t i6 u~voldably produce~ In ca~e of ~ rare
earth magnet, e~pecial;y a R-Co type magn-t, a treatment Or the cut du~t
1~ ext~emely important ~ecau~e cobalt hac ~ bad e~ect to a human body,
and lt requlre6 3 recovery unlt o~ the CUt ~U6t .
rurther amon~ the conv~ntlonal mo~ltlng method6 by u~in~ a thermo~ettirs
15 resln, a pre-s moulding wa~ a cQneral, but an in~oction mouldln~ and an
extru~lon mouldin~ were not wldely us~d and a th~rmoplaG~ic rerin w~
commonly used
~ccordln~ly only a fow ~tho~ wore ~va$1~blo to c~r~ ~n uncured ma~n~t
by h~t~n~ ~oul~ y th~ ln~eotion ~ouldlnc an~ by thQ extru~ion
~ 20 mouldin~, and tho ~ethod wa~ to ~cur- ~ cyllndr~cal ~h~p- o~ th~ ma~not
,; with a c~t~l~ug~l force by rotatlng a ~1~ a~t~r ~lxln~ lt~ outor
~ . ~
~ ` d~moter to thQ ~1~
,, .
:
., ,
': ,
~' ~
` , ...
,
. , . . ~
1'; ~ . , - -
. ~, .
~- ,. . , ; ~
2 ~ L ~ i C~
The problem6 of ehe aforadQ6crlb~d conventional t~chnolo~y are ~ummazize
a6 below.
Fir6tly lt 16 a u~e o~ a thermopl~lc r~sln Çor moul~lnc a ~a~net ~y an
ln~ectlon ~oulding an~ the QXt~U~lon moul~t n~ . ~n ordor to ~a~ a magnet
moulded by ~ th~rmopla6tic resin to b~ u6~1e ~von 8t a t~P~aturo a~
around 150C, it~ mouldlng t~mP~r~ture ha~ to b0 ~t 2000r or more.
: ~herefore ~ ~agne~lc pow~er bl-nde~ wlth the reoin i~ xpo~e~ at 6u~h a
te~perature.
W~en a rare earth ~a~net, Q~peclally a R-~e-B type m~gn~t i8 u~e~ a6 2
. 10 ma~netic powder, a deter~oratlon o a ma~net perfo~mAnce of the ma~ne~
happen~ due to an oxldatlon o~ the magnetic powder at a hlgh te~perature
above 200~c slnce the magnetlc po~der 19 ~a~ily to ~e oxldlze~.
Moreover, the Iher~,oplastic re~in has proble~ on heat resl6t~nce ar.
~olvent resl~tance when compared wlth a thermosetting re~ln.
Next, method~ of the curin~ bY heat~ ng after mouldinq by uclng th~
the~mo~etting re~ln are polnted out. For a moul~n~ by u~lng th~
th~rmo~ttlng resln, lt re~ulre~ th~t th~ r-~ln po~ Q~ ~ ~harmopla~tlc
property ln a c~ta~n te~p~ratura r~ion. Novorthel~ thl~ temp-rature
~ ~gion 1~ low~r or hl~h~r th~n th~ th-rm~ettln~ tamp-rature, it t
neca~ary to ~ecur- th- hape onco moul~od ln or~r to cure lt.
:; '
n ord-r to ~chlevQ lt, ~-tho~ ~n thc con~on~lonal t~hnolooy ~rQ
~ avail~blQ. ~ow~ver ln ~ convantion~l productlon proc~s o~ ~ cylln~ric~l
: ~e6in ~ound type ma~not, ~lnce th~ lnn-r dlamat~r 1~ not ~lxod, ~ ~lxing
_ 9 _
... .
. .
:., .
.
... . .. :
. ~ . . . .
-, ~. , . .. . ~ ,
,., . - ~ .
2~' 9~r!~i
iJ , :. ~, . i r
~i~ of the outQr ~i~motar 1~ rot~d wlth a ~a~ple to ~ecure tho ~ha~e
durlng ~he e~rlng, and the ~1~ for thlo purpo~e ~ thu~ ro~u1r-d-
Furthsrmore ~t 1G difflcult to op~tat~ th~ curin~ treat~nt for loto of
ma~n~tc ~y eh~ m~ehod, and it h~ pro~l-m~ ~uch a~ ~ ~urin~ tr-at~ent
5 for a lons ~iæ~d ma6nat moulded by an ~xtru~lon ~oul~lng m-thod i~ al60
dl~flcult, etc.
~urther ln the pa~t, ~8 to A part1el- ize of a magn~tlc pow~er ln a
re61n ~cund typ~ m~qnet, a conc~rn of an ox~d~tlon when the ~agnetic
powder wa~ flning wa6 con~er-d, but no con6ideratlon of the p~rtlcle
lo slze of the maqn~tlc powder from ~ vlewpoint of ~ thickne~ of a ma~nQt
moulded article wa~ con6_dere~.
~urther in ordsr to mculd a m~gnet with a thicknes~ of lmm, 1~ wac
nece~sary to make the decire~ thlckne~s ~y a cuttlng fabricatlon afte-
moulding one with the t~.lckne~ mo~e th~n lmm by a prQc~ moulding or an
lS ln~ectlon mouldlng ln advance.
~7~wever the particle E~iZQ 0~ agn~t1 c powder 5~1v~6 a larse lnf luenc:e to
the thlckne~ of ~ moul~ t~ clQ o~ ~n ~nlsotroPlc ro~ln boun~ type
magr~-t . Namel~ 1~ th~ av~r3~ p~rt~ cl~ ~ ' z- of a m~n~tlc powder Co--
not chAn6e, ~n orl-rltation o~ one ~egn~t~c p~t~cl~ ~f~ct- mo~e to a
20 do~rQe o~ tho oriontatlon o~ th~ ~on~t ~y thlnnin~ tho th~clsn-~ o~ 'cho
moul~ ei ~rtlcle. ~o~ oxampl~ n ~n ani-ots~oplc ~a~net wlth a
thlckn~ of 0 . ~m 1~ ~noul~Q~ th- ~v~r~oe partlcl- ~lz~ o~ the
ma~n~t~ c powd~r ic 50~1m, th~ ln~lu~nc~ that one ~yn-tlc pa~t1 clQ qlve6
to ~h~ orlentAtlon læ ~round 10% . Although the ln~luQs~ce 1~ re~uc~d i f
. -- ~o -
.
;~,
',''',
. 1 , . . . , . ,. .- .
. . ~. - .
. . .
. . . :
2 ~
the thlcl~ne6~ of th~ moulded ~rtlc~@ b~comQ~ 0. 5mm or more, the lnflu~nce
ls enlarged lf the th~ ckne~ b~com-~ thinn~r. Accor~ ly ~ to the
aVQrage part~cle ~lz~ of the m~ne~, ~ pro'Dle~m 10 g-nerated that lt
~houl~l relate to th~ thlckn~c of th~ m~ t moul~led ~r'cicl~.
s ~urther by a conventlonal ~otho ~o moult a m~n~t wlth the thlckne~6 lm~
or lecs, it rellult~ a hl~h proauctlon co~t, ~tc beca-~ce o~ the
fabrication procss~ requ~red.
Further, ~ rar~ earth m~net, ~sp~clally ~ raxe aPrth~ron-boror. type
magnet wa~ ea611y oxldlze~, and th~re wa~ a problem of a forma~lon o a
lo ru~ during lts servic~.
~n ord,e~ to ~olve the problem, a coating method of a resin on the magne~
moulded, a metal pl~tina and a coating of a cer3mic or h resin o~ the
~nagnetlc powder WQre investigated in the p~st.
~ 3owever followlng problem~ ar~ anumerated ln 1;he aforement.ione~
15 conventlonal ~u~t r~ tance techno3ro~y o~ a~ne~.
r'
rhe fo~mQr methot ln whlch a r~sln 1~ coat-t on ~ m~ oul~d doe- not
havQ an e~ect to n oxidl~tlon o~ th- ma~n-tlc p~wdr~r dur~ng the
. ~ mo~l~ln~. ln oth~r wt)rdo, wh~n an ln~sction mould~n~ or an Qxtruslon
onoultln~ i- perorm~, th~ ma~n-~ic pow~r ~ ~ sx~o~ undQr ~ high
20 ~mp~ratu~- durln~ l~ne~dln~ of ~ notlc pa~ r ~nt th~ r-~in or
.. moul~ln~ th- m~ tlc p~w~r c~ln ~ oxi~lzed ~t 'chl~ ~ta~e r~oultlng
po~Elbllity o~ tho mould~ n~ and ~ de~rlor~tlon of ~ m~gnet
,
-..,
.
.
',
2 ~
performance. Moreov~r ~f a 11ght ~in hole 1~ pre~l~nt ln a coatin~ fllm
a~ter the mouldlng, 'chere 1~ a problem th~t ~he ~a~no~c ln01~e ~ lc
oxidized from it.
Frorn con610.erlnq thQ6e probl~, the latter In~tho~ ln whl~h a meral
5 platln~ or a coatlng wlth a cQramlc, a r~cin, ~c on th~ magn~tic powder
m~y be a mathod to ~olve the afo~em~ntionod pro~l~m~.
Xowever the latter method ~tlll h~ a probl~m. ~rhQ av~ e partlcle ~iiZQ
o~ a magnet~ c powder io c~veral ten mlcron~, lf a ~llm lc coated or. ~t,
it~ thlckne~6 ha6 to be 1 mlcron or lel~, and th~r~ore thare ie; a
lO problem that the f llm coa~ed ha~ to be extromely tou~h and ~tror.~ly
. ~ adhe~lve or it ha~ to e~tabll~h a product~on proce3~ not to remove the
fllrn co~ted.
'
~urther ln the pa~t, a thin plate ~t~te re~ n bound type ma~net wa~
malnly produced by a calendar mouldln~ m~thod, an extru~ion mould n~
15 ~nethod and an lnject~on mouldin~ method.
For ~ach mouldlnq method, A mixtu~e kn~ad~d of a ~a~netls powder and a
thQrrnopl-et~ e ro~ln ~o u~ and ln ca~- o~ ~ho cal~ntl~r ~nould.ing m~thod,
the sfor~e~crll: ~d ~ net ~el~ mat~ri~l ls ~a~e ln ~ thln pl~t0 ct^.te by
roll~ns ~th hot roller8.
20 ~sowev~r the pr~duc~lon proc~ o~ th~ ~forem~ntlon~a ~hl pl~t~ stat-
~: r~in boun~ typ2 ~n~sn~t h~- ~elow~ tad prcblamo.
. .
, . .
: - ~ 2 -
;.
..,~
.-
. .
.
.: : :
' ' .'
~ ~ "3 ~ , 3
n c~3e o~ the cel~nCar mouldln~ m~thod, Qn l~otrop~c mou~d artlcl~
can only be obt31nad wh~n a rare ~ar~h ma~n~tlc pow~er 1~ u~o~ ~lnc~ lt
16 not po~01ble te ch~rGe a ma~eSic fl~d durlng ~h~ ffloul~lng, and thu6
a magnet performanc~ of th~ ~agn~t le low,
~urther b~c~u~e o~ a h~atlng capaclllty o~ ~he roll~r~, lt 1~ not
po66ib~e to u~e a ra~ln hav~n~ ~ very hl~h meltln~ po1nt ~ a blnder, an~
the heat re~l~tance of the mouldcd ~rtlcl~ 18 inferior.
Furthermore lt requiro~ a c~rtaln flexl~llity in tho mouldod artlclOE ~or
the moul~ln~, ~nd therofore en amount of a m~gnetlc powder in a raw
lo materlal can not b~ con~lderably lAr~e re~ul~ing a low m~gnet per~orm~llce
of the moulded art~cle.
/
, ( 2 ) ~ n ca6e 0~ a moul~ln~ of a thln plato etate ma~net by ~n extru610r
~. moulding ~Qthod, an unevenne~ of the moulded art~cle i~ likely to happen
,: due to a dl~rence of thQ oxtru~lon ratc between ~ cenrral poln~ ar.~ ~n
,: 15 outer polnt o~ th~ outl~t o~ the dl~. Accordlngl~ in or~or to pro~uce an
~ cven moul~e~ ~ticle, a co~pl~cated d~cl~n of the pas~a~e ln the tl~ 16
requlred and the ~ie bQC0~6 ~xtr-m~ly expen~ive.
Fur~h~r when the mouldln~ 1~ carrled ou~ ln a m~nQt~c iel~, the g~p
betw-en pol~ p~ 0c~ c~n not ~-k- v-ry s~all bQcau~e o~ ~ conc-rn of
20 ~chan~eal ~tr~n~th of th~ nd t~w th~ netlc fi-ld to b~ char~-d
,: ~t tle ~oul~ln~ CUl not ~- v-r~ hC~h. conooquontly ~ m~nat p~r~for~ance
o~ moulded 4rtlcl~ rlorat~d.
:'
':"
- 13 -
,~
.
-. ~
2 ~
~3) In ca~e of ~ ~ouldlng of k ~hln platQ ~te ma~n~t by ~n in~e~tlor.
moulded, lt i6 dlfflcult to mould on~ h~vlno a thl~kn~s of lmm or 1~
~hls 1~ due to ~ ~neration of ~ poor mouldlng by an in~u~icl-nt packing
of the mouldln~ raw mate~lal lnto ~ha cavlty of the ~ th- thlckne~c
5 :i6 thln, ~lnc- ~he ~ould~ng r~w m~terlal ha~ a poor ~lu~dity containnln~
A lar~e amo~t Of a ~gnetlc pow~r.
~urther when an anlso~roplc magnot 16 mouldQ~ and if th4 th~ ckne~6 18
t.hin, a moul~ing Wlth a ~ub~tantially ~-otroPY can only be obtalne~
becau~e of an ~f~ect of a Bkin l~yer ~ 0~c~10n where ~he ratlo of the
re61n i6 htSh) of the m~net Burfqc~
Fur~her a bl~ mouldeng ~achine iB r~ulred to mould a magnet havlng a
large area, and it lc dl~advant~eous f~om a moul~lny cost.
Thl~ lnvent~on, thera~ore, ~6 to ~olve the ~bove~ u~ed proble~, and
lts ob~ectiv~ ~6 to p~oVi~e a re~ln ~ound type magnet wlth a hl~h ma~ne'
; 15 performance, a~pecially a lon~ ized c~lindrlGal r-sln bound type m~gnet
havlng a r~dlated ~ni0tro~ n~ to provl~ ~ pro~uct~on procQ~ of the
magn~t wlth ~ ~oo~ product~v~ty.
,
Further the o~ectlv~ 1~ to ~rovl~ ~ pro~ctlon ~roc9-~ of A m~gnet wlth
~ slm~l- cUtting ~-tho~ without a cr~ck, a brQ~k~c and ~ do~ormatlon.
.,.
: 20 rurthermore thl- lnv-ntlo~ a~m~ to provld- pro~u~tton proc--~ wlth
impll~yln~ th- product~on ~roce~ ~nd wlth r~ducln~ a co~t, bY ~mproving
magn-t ~er~orm~nc~ o~ Qt moul~d by m~an- of -tabll~hln~
14 -
,'
, . .
. , , . ~ . .
~ .... :~: .
~ .~ .. .. .. .
.. .. .
2 ~
relat~on ~etween a ma~netlc powd~r ~nd ~ thlcknes~ of th~ ~a~net, ~nd ~y
moul~lng a ma~net by an ax~ru~on wlth ~up~rlor oxld~tlon rssll~tsnce and
weather res i 8 t ance .
Moreo~er thi ~ ~nvantlos~ a~m~ to provide a productlon p~OC-Bf~ wlth ~1 ~ood
5 p~oductlvlt~ for ~ hi~h per~or~a~c~ thln p~ate ~t~tQ r-~ln bound t~rpe
rare earth ma~ne~.
. ,
BR~EF EXPLANAT~ON OF FIGURF.S
Flgure 1 16 a 6ketch of an extrucion mouldln~ ~achlne use~ in Example cf
. thi ~ lnvent lon,
: 10 F~.gure 2 16 a 6ke~ch of a die oetrucSure for 8n extru~ion moul~ng in ~masne'~c ~leld of a cyllndr~cal re~ln bound ts~pe ma~net u~ed in ExamPle
of this lnventlon.
. , .
Flgure 3 ls a ~ketch o~ an ext~usion mouldlng machlne u~ed ln 8x~mple of
thi~ lnventlo~.
15 F~ cure 4 1~ ~ oJ~tch o~ ~ p~ o ~gn- ls~tlon unlt u~d ln ~xAmple of
thi~ inventlon.
Flgura 5 l~ a g~h ~howln~ a r~l~tlo~ b~tw~-n ~ ma~tlc ~lel~ ~or the
~o~ ln~ ~nd ~ r~ldu~l ~aan~tl~ ~lux d~n~lty o~ th- ~oul~d ~rticle,for
c~,-e- wlth and without a ~netlæation o~ a m~onetlc powdor prlor to tho
20 mo~ld~ ng.
- 15
, .
. ~ , : ~ . , , ;
~ ~ .
~ .:
:, ' ' ~ , . . .
. ~
2 ~ .'t3
; Figure 6 lB a ~ketch of a ~e ~tructur~ for an ~xtru~lon mouldin~ 'n a
magnetic fleld of ~ thin plate ~t~te ro6in ~oun~ type magn~t u~ed ln
Exa~ple of thl~ lnventlon~
Flgure 7 16 a graph ~howlng a rolation b6tw~Qn a magnetlc ~ield ~or
ma~netl~atlon be~ore the mouldlng and a rQ~udlal ~gne~lc flux d~nsity of
the moulded artlcle,
~,:
Fi~ure 8 i~ a s~t~h of ~n ~xtrusion mouldln~ ma~hlne ~d ln Exa~ple o~
this ~ventlon.
Flgure 9 is a 6ketch of a dle etr~cture for an ex~ru~lon moul~ng 1~ a
m~gnetlc fleld of a cylindrical resln bound type m~gnet u~ed in Ex~mple
of thla lnvention.
F~gure 10 16 a cke~ch of an extru-ion ~ouldlng machlne used in Ex~mple ;6
and 17 of this i~vention.
.~ .
gure 11 ~8 a ~k~tch of Example to cut ~nd to m~k~ a thln plate ~ta~e of
~a 15 a cyllndr~cal r-~ln bound type ma~n~t mouldQd bY ~n ~xtruclon ln Ex~mpl~ 16.
.,
Figure 12 1~ a ~k~tah of a pr~ca unit ~r mould~ng o~ a th~n plate ~tat~
! ~a~not u~d tn ~x~Pl~ 17 of thi~ lnvQntlon.
.}~". '
hl~ ~nv~ntlon 1~ ~ r-~ln bound typ~ magn~t nd it~ p~oduction proc--~ ac
. 20 de~crlbed b~low.
- 16
:; : :
~, ' ' ' ' ' ' i ' . ' .
~. ' ' , ., ' ' ' , '
f
2 ~; f. I,J ~
~1 ) A resin bound type magnat compr~ ~lng a ~netic powd.*~ ~n~ an oro~nlc
re6in wh~reln ~ t 16 moulded ~8 a ~ln~le body ln ~ ~yllndr~cal ~ors
satlEfying a r41atlon ~ c
2D~ / d ,~, 1
5 amon~ 'che outer ~lameter ~D), the ~nner dl~m~r ~d) and the len~th ~L~
o~ the magn~t, ~nd lt ~160 h~6 a ra~iat-d Anl~ot~opy ln th~ diameter
, d~ rectlon .
~ 2 ) ~ ~ompo~ltlon o~ a re~in bound ty~e ma~nat o~ the a~orementione~
inventlon comprises a ~agn~tlc powd~r, ~n organlc r~in and an a~d;tlve.
10 ( ~ ) A p~oduction process of ~ r~ir, bound type magnet where~n a raw
material for the mouldlng compri6inq ~ maqn~$c powder and an o~ganic
resir, 1~ moulded ~y an oxtru6ion by p3~sing throu~l3 a dle lr, hh:ch
, . ~
magnetlc field i8 charged while lt 1~ b~lng cured, i~ ~orme~ ~ a lng;e
body i~ a cyll~ldrlc~l form ~ati6~ying a ~elatlon ~
2DL / d2 ~ 1
among the outer ~iameter (D), th~ ln~-r ~iameter (d) and the length ~L~
of the ~1 ~agn~t an~ lt ~l~o ha~ a r~ ted ani~otropy in
th- ~lameter dir~ctlon.
(4 ) P. co~po~tion of a re~ln bound ty~ magr~-t ln thQ product~ on Prococ~
20 Df ~hQ a~o~-~sntlon-~ lnvontlon com~rllle~ notic Dowd~r, ~r or~nic
. r-oln ~n~ an addltlvo.
l5) A productlon proco-ll o r~n ~oun~ typ~ magn~t by an xtruc~on
moulding of a moul~ing raw m~tarlal co~prl~ q a m~g~-~lc powd-r and ~n
- 17 -
.
~ ,
::
- , - - - ~ . ~ . -
.. . . . ..
, ,., . . ~
-: : ' ` - ' ~
2 a ~
or~anic re~ln wherein a d~e ~tru~ture for mouldln~ 1~ con~tltuted that ~
front ~nd of a m~n~rQl ~-ction 15 p~o~ected n front of an odge of a
outer die, ~ m~gn~tlc clrcuit 1~ for~Qd b~tween the ~al~ mandrel ~tion~
~ tro~a~n~tlc coil lnotalle~ at an outor ci~cume~oncQ ~ the
~ oald dle, it 1~ moul~ed ~n a cyllndrlcal form by
; charglng a m~gnetlc flold in the d~e by thc el~ctromagn-~tic co~ nd
th- moulded articlo extrud~d 1~ de~agn~tl~od at the ~ront ~d of the
~an~rel .
~, .
( 6 ) A Compo~itlon of the ma~net oÇ the aore~ent~oned lnven~lon compr~ca~
10 a ma~netic powder, an orsanic rs~ln and an addltlve
~ .'
,
( 7 ~ - A production proce~ of a rQ~in bound type magn~t ~y an extr:lslon
moulding o~ a moulding raw material comprl61ng a mAgnetic powder ar~d an
organ~c re6in wherein an clect~oma~etlc coil 16 inçtalled at an ou~er
clrcumference of a d ~ ic moulded ln a cylindrical ~orm ~y chargin~ a
~a~n6tic flel8 in the ~io, an ~lectromagnetlc coll with ~n alr-corQ ic
al~o in~tallod ~n front of th- a~orementioned olectromagnetic coil to
~n~rate a ma~netlc field ~or ~emagnetl~atlon ~n the ~ electroma~netic
coll, and th~ mould-~ articl- xtru~e~ ~B de~a~netized
.
) A compo~ltl~n of th- ma~n-t o~ the ~forom~ntlon~d lnv-ntlon comprl~-~
0 ~ mognetlc pow~-r, ~n or~an$c r-~ln ~nd ~n addltlv~
,
~9) A productlon p~oco-- o~ r--ln ~oun~ typ~ n-t whlch 1
con~t~t~t-~ ~y or~ntat~nC ~ ~aon-tlc ~owd~r ln ~ molt-n mlxture o~
~agn-tic pow~-r ~n~ ~ ro~n $n ~ ~ctlon wh~re a ~gn~tlc fl~
~,
~, '
,. .
~.:
:, .... .
,; . . .
.
., .
~: .
.,- ~,
.
2~
charl~ed at a ~ront ~n~ of a ~le, mould~n~ i~c in a cylindr1cal orm,
~ol~di~yinq lt wlth cooling and Dx~rudin51 1~ wh~rQ~n wh~n 'chQ magnQt
cut, the re~in iB cut by mel&ln~ ~y con~ctlng thQ ma~nQt wl~h a he~t~
~ f
wlre .
,
S ~ 10 ) A p~oductlon proC~B~ of ~ r~ln boun~ typ~ magnet whereir.
compo~itlon of the molt~n ~ixturQ o~ the afor~mentloned lnv~ntlon
compri~e6 a masnetic powd~r, ~n organlc re~ln and an ad~ltlve.
~11 ) A productlon proce~; of a ~ln bound type magnet of the
aforement~one~ (9) or (lo) wher~ln t~e ~e~n bound ty~e ma~net 15 an
10 160troplc magnet mol2lded by an extru~ion in a cy~indrical form wlthout an
orlentatlon.
1~
( 12 l A p2~0ductlon prOCQ1~6 of mouldln~ & ~e~ln bound type magnet ir; a
cyllndrical orm by an injectlon moulding or an ~xtr~610rl moulding of El
ma~netlc powder and a ~chermoe~ttin~ ln whereln ln orde~^ to cure the
;.. I5 moltRr~ Dlixt~e of ~ m~gnotlc powd-r ~nd ~ re~ln by hee~ing, lt i~ cur~d
by hea~cin~ with flxln~ the out~r clrcum~erQnce o~ the cyllndrleal magnet
. by a ~lg and thQ inn-r circu~nference by ~n ~la~t~ ~ater~al ~xpand-d by a
ga~ .
t1~) A produetl~n proc~c o~ ~ r~ln bound typ~ m~gn-t wherQln ~
compooltlon of tho ~olt~n mlxtur~ of th~ afore~ontlone~ lnventlon
comprl--~ a ~i~n~tlc powd-~, an or~nlc r~-ln ~n~ an adtltlv~.
~."' !
.,' .~
,.; - lg -
'" . "
'' ' ' ~ ' .
"'` " .` ". , ' ' ' ' ' ` ". ~ ~" ' '
''; ' . . `. ~ . ` :
~ 2~ 7~
.' (~4~ A pro~u~tioll proces6 o~ a re~ln bou~d ~ype ~asnet of the
aforementlone~ (12) or (13) wherein the aforement~on~d ela~tlc materiai
5 a ~lllcone rubber.
~- (15) A pro~uctlon proce~ o~ ~ re6~n bound type maçnet com~rl~ing a
ma~netlc pow~er ~nd ~n or~anlo re~n wherQln a mixture o~ ~ rare earth
magnetlc powd~r premagnetlzed ln a ~agnetic f~eld whlch ic ~tron~er than
a coerclve force of the ~a~netic powder ~nd ~ org~nic r~01n i~ kneaded,
and the ~neade~ mlxtu~Q 1~ moul~ed b~ an extru~ion ln a magnetlc fleld.
. (16) A product~on proce~ of a resin bound ty~e rare eRrth magnet whereln
a compo61tlcn of the ma~net of ~he aorementloned ~nvention comprl~eE a
masnetlc powder, an organic re6in and an a~ ive. : .
.
s (17) A production process of a resin bound type magnet by an extrusisn
moulding of a moulding raw material comprising a magnetic powder and
~:. an organic resin with a die in a magnetic field wherein it is moulded
by an application of a slight vibration to the die at the moulding.
) A pro~uctlon proce~s of a re~ln boun~ type rare oa~h ~a~net where~n
~; a compo~itlon of tha ~agnet of the ~or~m~nt~one~ ~vontlon comprl~e~ a
gnetic pow~r, n or~anlc re~in and ~n a~ltlvQ.
,
;
tl9) A r-cln boun~ type m ~net compri~lng a ~a~netlc ~o~dor ~n~ 8 resln
20. ~her~n a~ ~vorago p~rtlclQ ~ r o the ~foroment~onod magnetlc powder
~ - .
6atlcfie~
r ~ 0.1 t (t ~ l~m)
- 20 -
r,
t;' '
t,'
i, .
,' ;`',. :
t ', . ' .
~,', ~. '' .,.' ' ' : ,
.' ' -., ,, ~ ' ' .. ' :
r: .
, .; ' ' . '
' ' ~ ~ . ' '
2 ~J r
with the thlckne6s t of ~h~ ~ouldQ~ a~t~clc o~ an ~n~ot~o~lc re~ln bo~nd
~ype magnet compri~ln~ the ~ald ma~n~tlc powd~r ~nd th~ ~o~ln.
(20) ~urther~ ~ a re~ln bound ype r~r- o-rth ~net
wh~reln a compo~tlon o~ the m~nQ~ of ~he a~orementloned lnventiOn
comprl6e6 a magnat~e ~owder, ~n or~anlc r~ and an ~d~itiYe.
(21) A productlon Proce~s of i r~tn ~oun~ ty~e magn~t comprlJlng ~
magnetlc powder ~d a re~ln whaL-eln an ave~age ~artlcl~ ~ze r of ~he
aforement~oned masnQt~c powder s~tic~le6 c
r ~ 0.1 t ~t S lmm)
wtt~. the thicknes6 ~ of the moulded erticle of an ani60trop~c resir. bcund
; type magnet comprl~ing the ~ld ma~netlc powder an~ ~h~ ln, and the
magnet i~ produced by an ext~u610n moulding wlth a die in a ~.agnetlc
field.
(22~ A production proce~ of a re01n bound type rare arth magnet wh-rel~
a compo~ition of the mfl~na~ o~ the a~oremQntloned ln~entlon co~pri6e~ a
magnetlc pow~er, an or~nic r~sin an~ ~n ad~ltlv~.
2~ ) A pro~uct~on ~roc4~c o~ a r~-ln ~oun~ typo magn~t cotnprt ~lng A
~noul~ng of ~ mlxtura o~ a magn~t~c l?owde~ ~.n~ ~n or~ar,le rQ~ln by an
ln~ect~on ~oul~lny or an Qxtru~on moul~lng wh-reln a contpound $
20 pr-parQ~ by ch~rgln~ in a lul~a~ln~ ~ch~n~ aft-r malcin~ a v~co~$ty ~i
th~ mix~u~- of th~ ~or~on~lone~ ~a~n~t~c pow~r ~n~ or~anic ~e~ln ln a
~tase o~
~5 8 ~pol-~ (ah~ar rat0 ~ 10000 ~X
t'y /~ 21 -
.
, . .
. . ,~ .
: . ~ . ... , ~ ..
. ~ . -
.. ~. . ... . .
,
. ~ - .
- - -
r ~ ~
(24) A pro~uctlon P~ocQ~ of D r~ln b~und typ~ ma~net wh~in
compo61tion of the ma6n~t o~ the aforem~ntlon~ inven~lon comprl0@c a
magnotic po~der, ~n or~anic r~ln and an addltlv~.
~25~ A productlon proce~c of B reæln boun~ type ~a~net ln th~ ~n~ntlons
of the aforem~ntlonQ~ (23) and ~ wh-r~ln the ~ur~c~ of ~hQ ~agnetle
powde~ 1~ coated wlth a metal pl~tln~ or csramlc~.
' ,
~26) ~ produc~ion p~oces~ of a thln plate ~tate r~sln bound type r~re
earth m~net whe~ln ~ mo~ in~ r~w ma~e~tal com~rlEln~ a ma~netic p~w~er
and an or~anie re~ln 1B moulded by an ~xtru~lon ln a cylln~rlc~l m~gnet
lo by pas~ino lt throu~h a d~ e, then one or pl~lral polnt6 on the
c~rcum~ercnce of: th~ eald cyl~ndr~cal magnet lE/are cut ln a directlon
parallel with the central axi~ of the moulde~ artl~le and the mo~llde~
article cut i~ sprQa~ to make lt in a 'ch~n plate ctate.
( 2~ ) A production ~roce6 o~ a re~ln bous~d, type magn~t wh~ein a
compo~itlon of tho mo~ld1n~ raw matQ~141 of the aor~montion~d lnvention
compri~e~ a mOE~netlc ~owd~r, ~n or6~nlc re~ln ~n~ an ~ditive.
(28) A productlon l~roc-!~ of ~ ln boun~ typç II~ACIn~t ln th~ ~nv~ntlon~
o the a~or-m~n~ionQd (26) ~n~ ~27) ~hore~n th- out~r dl~ter (DJ of th~
cylln~rlcal m~gnot to bQ moul~ by an oact~ on ~n~ thQ ~nnQr dlameter
. 20 ~d) ~ntl~y ~ ralQ~lot~ o
0.75 ~ ~ ~ D ~ I. C--
2 - : :
-~:
,: -
- ~: ' '' ''' . :
- - ; ':
2 ~ $ 7 ~i
~29) A productlon proc~s~ of a thin plate ~t~te ~ln bound type rare
e~rth ma~net wh~eln ~ mould~ng r~w m~t-rl~l comprl~ln~ a m~n~t~c powd~r
and an orCan1c r~in i~ pa~ae~ ~hrough Q ~ whera ~ netlc fiQld 1~
charged to mould ~ cylindrlc~l ma~net h~vin~ a ra~latqd ~nicotroPy ln the
S diameter dirQ~tlon by an ~xtru~ion, than one or ~lural ~olnts on the
circumfer~ncQ of tho ~a~ cyl~ndrl~ agn~t l~far4 cu~ ln ~ ~r~ctlon
parallel wlth tho c~ntral ax18 of the ~ould~d ~rtlcle an~ th- moul~e~
article cut 1B spread to ma~c~ lt ln a thln plate ~t~te.
130) Furthor a productlon proc~c6 o~ a re~in bound type m~gnet wherein
compo61tlon of the moulding raw ma~rial o~ the inventlon of the
aforementioned (~9) comprl6st a magnetic powder, an o~ganlc re~in end an
. additive. :
~31) A productlon proces~ of a reoln bound t~pe magne~ in the invent10nC
of the aoremontlo~ed (29) and (30~ whereln the outer dlameter ~D) of the
cylindrlc~l m~gnat to be mould-d ~y ~n xtrucion ~nd thQ ~nner ~am~t~
~dl ~atl~fy a rel~tlon of
' O.B5 ~ 8 J D c ~,
~ ~ (32) - ~41~ ar- tho~ in whl~h the rna~notlc powdor, the o~-nlc re~in an~
the ad~itlvo~ ~r~ llm~to~ ~or t~i- lnv~ntlon.
.~; ', - .
As or ~ magn~tlc ~owd~r whlch can ~o appllo~ ~n~thl~ ~nv~ntlon, a
- errito ~am~ly ~a~n~tlc powd-~ nd ~ o-c~ rth ma~n~tlc ~owd4r
uc~ m-on-t~e powd~r eo~poolnc of ~ r~r- ~rth matal ~n~ trancitlon
: m-t~ a~nly con~lt~t~no eo~lt ~na ~ron ~ a~ic compoclt~on, or
~ - 23 -
,~
. :
,. . ..
.. .
. ~ ......... ...
.
.. , . - ..... . .
. ;~ . .. . . .
-, ' ' ~ ~
2~
magnetlc powdex co~po6ln~ of a r~r~ oarth mQtal, tran~ltion mQt~l~ mainly
con6tltutlng lron ~nd. ~oron ~ a b~-tc compo~itlon, otc ar~ ~n~lnerated.
A~ for an or~anie re~ln whlch can ~e app~lfid ln ~hl~ lnv~ntlon, le c~n be
elth~ a ther~opl~tic r-61n or ~ tharmo~ett~n~ r~in, and a~ for the
thermopla~tlc resln, for ~xa~ple, a pla~tic ~uch a~ polya~lde,
polyprop~lene, polyc~rbonat~, polyph-ny~-nog~lph1de ~PPs), ~tc, an
: ela~tomer such a~ chlorlnate~ polyethlene, ~thylQne vinylacetate
copolymer (EVA), etc and Eynthetlc rubbe~ are num~a~
A~ for ~he thermo~ettlng r~ln, ~or ~xampl~, ~thylQne ~amlly un~aturatQd
polyester re~ln, epoxy recin, etc are ~numerated.
Further a* for the a~ditlve, a lubricant to re~uce an ex~rusion
re6i6tance ~t the moul~lng ~uch a~ 3 ~etal Eoap (~inc stearate, calc~lm
stearate), wax, etc c~n be u~e~, and a6 ~or th~ ~forementioned
clo6~1~nkable thermo6e~tlng re61n, ~n addltive ~uch a~ pqrox1tec whlch
l~ ~ccelerate6 the ~locsllnking re~c~ion c~n al~o bQ ured.
,'"
~h~ ~agnotlc powd-r i~ u~ic~ntly ~lxod wlth th- or~anic re-in ~n~ 'ch~
~ltlvc 1f l'c ~c neco~sary. ~rhen tho ~x'curo 1~ cu~ ntly kne~d~d in
a ~n~a~lng m~chln~ with heatinç abovo ~ t~pex~tur~ at whloh tho org~nlc
: re-in io molt~n, ~ne. lt i- ~F~nulat~ 'rha ~aon~tlo compo~it~on
:~ 20 granul~te~ 1~ charge~ ln an ~xtru~1on ~chine, lt 15 ho~ted in a cyl~n8erto ~a~e lt ln ~ ~lu~z~ 6t~t~ an~ ont ~nto ~ ~lo by a ~erQw OL' a
. . .
; plur~er. ~he ~a~netic eompo~tlon 1n~ected. ln tho ~o ~ mould-a by
un~formlng ~cr~nt~ting) an axi~ oX e~y ~a~n~t$zation of the m~g~etlc
; -- 24 -
.,
.~
- ~ - - ~ . .: .-
, ~ . . ~, -
. ~ ~
2 Q ~
powder ln th- ~aw m~te~lal to ~ dlrection of a m~netlc 1-1d by pR~ln6
through a dle in whleh a ma~nQtic f$~ charc2~. The maqnQtic
co~po~tion i~ olldlfled with eoollng whll~ lt lc in the m~6notlc fleld
formed ln the ~ie, an~ lt i~ xtru~d. ~h- moul~d artlcle i~ then cut
into a cuitable lenoth. Wh~n 4 eloc~l~nk~ble or~n~c re~ln 1~ u-ed aR a
blnder, ~ter ~ dema~netlzatlon o~ the mould-~ artlcle cut, a
clo~clinklns o the or6an~ r~sin lc achievcd ~y h~at~n~ or an
lrradiatlon (r r~, electron bo~m, tc~. A recln ~ound type maCnet 1
thu6 p~oduced. .
10 Further the moulded ~rtlcle extruded from the ~ie 1~ demagnetiz~d by
ch~r~in~ magnetlc ~leld of a rever~e directlon to thc magnetic fiel~
charged ln the dle at the mculdlnç at a front end of the mand ~ h~
.,: . :.
: ~trength o~ the magnetic flQld i~ a~ûctQd by a dictance between ~he
mand~el ~nd a yoke of the ~l-ctromaqnetic coil. The moulded artlcle
15 extruded ~rom the die i~ al60 dema~netlzed by chargin~ a magnetlc ~leld
for an attenuation by pa~ln~ lt th~ough an electromagnetlc coll for the
dema~netlzation. A cyllndric~l r~-in bound ~net i~ thu~ produced.
,. ~" ,
Further thl~ lnv-nt~on i 6 w~ to facll~t~te ~n orl-nt~tion of ~
n-tlc ~owd r, to lmprov~ th~ n-tlc prop-rty ~nd to r-duce ~n
20 Qxtr w ion r~ tance at th6 moula1ng, an~ ic al~o b~n~flclal to ~ncroacQ
th~ mouldlng ratQ by an appllcatlon o~ a ultra-onlc o~lllator or a
m~chanical Ylbration ~uch a~ a vlbrator, tc.
- ~
.~
Accordlng to thi~ In~entlon, by ~eflnln~ an aver~ge partlcle ~lzo o~ a
.. m~net~c powd-r w~th a thickne~ of ~n ~nI~otroplc r~c~n bound typ-
~....
,i
"' - ;! S
" .
;. .
.
. . .
. .
... . . .
.~.; . , . , . - - ,- . .
:,: -, , -
~, ., ~ ... ,: .,
magnet moulded article, and th~ ~a~nQt i~ mould~d bY an ~xtru610n, it i~
poc~ible to moul~ ~ thin thiekn~o~ an~sot~oPlc m~net wlthout
postfabrlcatlon, ~n~ fur~her a hlah per~ormance ma~n~t 1~ able to mould.
~urther accord.~ng to thl6 1nv~ tion, ~ ha~ RC~I~ to ~revent a
S del~mlnation of a eoa~e~ film on th~ 6urf~c~ of a mapn~tlc pow~er and to
lmp~ove an oxl~atlon r~ tance of t~e m~gnat moul~ed by kn-a~ln~ ~
~ixture of the msgnetlc powdar ~nd a ~ln a~ter ~tin~ I t to m~e a
vifico~lty o~ the mlxt-lre at ~0~ Xpo~a- or l~ prlor ~o th~ ~nead~n~ to
ab~or~ the ~olten st~te ~e~in on the ~ur~8ce of th~ magnet$c powder
~0 resultlng a relief of a mechanlcal ~tre~.
Next, ln order 'co rnake a ~hin plat~ ~tate ma~net, one or plural polnt~ on
the c~rcum~erence o~ the moulded articl~ ln a cyllndrical form l~ cut in
parallel ~th the central axi~ of the moulded 8rticle. ~hen the
a~orementioned moulded article cu~ 1~ m~e ~n ~ thln plate 8 ate by
u~ing, ~or exnmple, 2 roller~, etc. The mould~d article 1~ then
6011dlfied with coolir~g, ~nd ~ cut lr,to a cuit~blQ len~th.
;
Further a~ an alternatlve m~thod., ~ter cuttln~ ~ cylindrlcal moulded
artlcl~ xtrudo~ lnto a ~ult~blo l~n~th, one or ~lural polnt~ on th~
clrcu~sr~nc~ o the anouldod ~rtlol~ i~ cut ln par~ rlth the cQntra
20 . ~xl~ o~ th~ moulded arti~ mould-~ artlcl~. ~ut $E ho~te~ ~n~ it 1~
~pre~d wh~n a v~coBity of 'cha moul~in~ ~rtlclo dro~ 'co m~ke a thln
pl~ee st3te.
- 2~ -
. .
, , . , ~ ,, -
.
2~3 Z,
A6 deccril~ed abov~, a mhgn~t of thls lnvont~on 18 ~uperlor to a
eonve2,tional ma~n~t, in ~hi~h plur~l m~çlnQtR are tlck-d, ~s~om a
vl~wpolnt of a rol~ abllity. Furthermor~ ~y an e~ppl~c~tlon of
production pro~4~ o~ thi~ lnvontlon,
5 (~) A cyllnd~lc~l r~ln bound type ~a~net wlth a hlgh ~a~ t peror~ance
can bo produc~ wlth a hlgh pro~uctl~ity end ~n oconom~c co~t.
'
( 2 ) slnce no OXC~1613 force or vibratlon 1~ ch~r5Jad ln th~ m~net ~t a
c~ttlng step ~y cutting an extrud~d re~ln bound type m~net wlth a wire
heate~ by an lclctric rG6ist~nce~ lt 16 po~lbl~ to cut an uncured ma~Jnet
lO whlch 1~ very ~rlttl~ and ~ ~hin thickne~ ma~net without ~ crack and a
breakage.
'' .
.. (3) A large amount of a thermosett1n~ treatment can be operate~ w~t~, a
low coEt~ th~ ~peration becomeE ~aey, and f~rther a dimenslon accura~y of
a ~yl~ndrlcal re~1n bo~nd type maCnet can ~ mproYed~
',
15 ~4) It hA~ a cignlflc~nt c~act ~or Q~5tll~incl a cyllntrlc~l m~gn~t h~vlng
. a rad.iated ~nl~o~rolpy ir~ met~r ~lroctlon though lt i~ dlfficult to
. q~t a ~trorg ~ tic ~ld at the mouldln~.
t5) ~t can b~ ly u--d ~or ~ magn~t~c ~en~or, ~n rseo~-r, an acutu~tor,
.
a llnear a~tu~tor whlch r~ulr~ A mlnlturl~atlon, ~ cl~on an~ a hl~h
20 p~r~o~mAnc~
- 27 -
'''~
.
- ~
: .
: . .
.. . .
~: :
.: . ,
., ~ , ~ '
. . . .
,
Furthe~ according to thl~ lnventlon by te~inln~ th~ ~v~r~ partlclQ ~_ze
of the ~açnet~c powde~ by the thlckne~s of t~ dn1~otroplc resin ~o~nd
type magnet moul~ed articl~ an~ by mou~lno ~he ~agn~t ~y an ~Xtrusion,
lt lC po~Bible to mould ~ thln thlc~ne~6 ~nlsot~opic ma6nQt wi~hout a
po~tfabrlcatlon, nd ~t 1~ al30 pb~1bl- ~0 mould ~ ma~n~t with a hi~h
perfo~an~e.
~urthermore acco~dlns to thls lnv~ntion by kneadln~ a m1xture of 8
ma~netic powaer an~ a r~ln a~ter he~tln~ lt to make it~ vl~coolt~ at 300
kpoi8e or les6 prior to the ~nead~n~, the re~ln in a molten ~tQte i~
,~ 10 ab60L-~ed on the ~urface o~ the magnQtlc powder, ~nd thus 1~ ha~ effectc
,.- to preve~t t~e coate~ ilm on th0 ~r~aCe of the magnetlc powder by
reli0v~ng a mechanical stre~ and to lmp~ove an oxldatlon re~lstance of
t~e magnet moulded.
~XAMPLE
,":
15 ~hl6 invention 1~ ~xpla~ned in detall6 in accordanco w$th examplo~ ~hown
below.
~:"
~xampl~ 1
Raw mætor~ w-re molterl to mRk- ~I compo~ltlon ~- Bm ~co 0.67~ c-~ o.00
FQ 0,22 zr 0.02~ 8.3S, a~tor c~t~nC, an ~n~ot produc~ w~ ma~n~tl~all
20 ~ure~ by he~t tro~tm~nt, an~ th~n ~ ma~ lc powder-o~ ~t- a~orage
p~rtiele ~ize lO~lm wa6 ~rep~r~ by crwhinç the ~ald lngot.
- 2B -
. ... , . ~
~, - - . -
. . ~ . ~ -
.,. ,,, . , ~ . :
,: : , .
' ' ~
2 ~ ~ ~ 1 r ~ ~
The ma~netlc pow~er, nylon 12 pow~r and z~nc 6t~rat~ pow~er w~re mix~c
to ma~e a ratlo of 92 wt%, 7,9 wt% an~ 0.1 wt% r-~p~ct~alY.
. :
: ~he ~lxture wafi kn~a~d by an 2 ~x-~ ~xtr~lsn ~n~a~in~ ~aohlnQ at 260c.
~ he kneaded mate~lal wa~ granul~ o ~Q ~ranul-~ of ~n outer ~ia~eter
l - lOm~, they were w ~d ao a r~w ma e~ial co~poun~ 111, and a
cyllnd~lcal ~agnet w~c produc~ by an ~xtru~ion ~achlne.
The mouldlny method 1~ explalned in occord3nc~ wlth Figure 1. ~he
moul~lng m~chlne ~on~i6t~ of a hopper i~ a raw ~at~rial char~in~ ~ection
101, a cylinder 102, a ~crew 103, an ad~ter plat~ 104 to e~ulp a di.e a'
the cylin~er 102, a dle 105 B~ a drlvlnq motor of the serew ~which 1~
not 6hown ln Flgure3, and further an electromagnet~c co~ 10~ to charge a
magnet~c fleld ln the dle i~ po~i~ioned at the outside o~ the dle 10~.
A yoke 110 eomprl~in~ a ~notlc mat~rlal is lnstalled a~ound t~.e
electroma~netic coll 109.
,'
The ~o~ementlon-~ granulata~ r~w m~t~rlal compoun~ wa~ char~e~ ~n the
xtruoion ~achin~.
: ~he ~-w ~at~lal ~ompoun~ 111 wa~ hQa~a~ at 263C ln ~h- eyllnder 102 to
m~ke lt ln ~ ~luillze~ 8tat~, ~n~ lt ~eD p~tao~ ~hrou~h ~he dle 105. Th~
~1~ etruetur~ hown ln ri~u~- 2.
- 2~ -
: '
.
..
` 2~Z~ 3
The dle i~ con~tltu~ by an ou~er ~$~ ~01 and ~ m~ndrel 202. A' ~hOUC~
the o~ter die 16 made of ~ non-magnetlc m~terlal, a rlnq ~h~p~ oUtQ~ dle
cectlon magnetic mator$al 201a to l~uce a ~net~c ~lux 1Y ln~t~lle~ at
the front Qnd. ~h~ m~ndrel 201 1~ ~160 mad~ of a non-~a~nQt~c m~t~L-~ al ~
and ~urther a mandr~ c~lon magnotlc materi~l 202~ i~ ln~talled at. 1~6
front end.
'
~hen a current 1~ pac~ed throuoh the electro~a~net~c coil 109 i~stal;ed
out~lde of the ~le, the ma~netlc flux goner~t-d flow~ alohg6ldQ of a
magneti~ flux flow H ~ho~n ln Fl~ure ~y ~n ar~ow ~tnce lt ~en~s to pac~
through a ~agnetic mat~rlal wlth a hl~h magnetlc perme~bl1ity.
Accor~ingly a radiate~ ~hape ma~net~c ~lel~ 1B ~enerate~ in a sp~ce
(hQreinaFter called a~ an orlentat~on ~ectlon) between the ront end 2C2a
o~ the ~ndrel 202 and ~he rlng shap~ outer die 201a of a magnetlc
~terial ln~talled ln the outer ~le 201. Th~refor~ when a magnetlc
compo~ltion pa~e6 through t~e orientatlon sectlon, ~t 1~ moulded Wit~. a
pro~l-ess of the orlentation o the magneti~ powder.
In th~ Exa~ple, the ma~netlc ~Qld ~or ~oul~ln~ wa~ 15 KOe, thQ
te~p~ture o~ the die ~t the ~ouldl~u wa- Z~O~C ~n~ the coollns ~a6
porformed by ~ ~orc~ alr ~ooll~ at th~ outl~t ~ctlon o~ th~ ~1Q~
AccordlnglY, ~n orlent~t~ r~w m t-rlal ~omPOun~ wa6 ~oulde~ by an
,.,
xtru~Tlon wlth ~ ~olldl1eatlon wlth coolln~ at th- outl~ o~ t~ d~e.
Th- ~læ~ o~ th~ ~nould~d ~rticl- t~O.B- th~ out~ lamet-r 32mm, the lnn~r
di~meter 30mm, ~d the longth wac cut ~n~o 22mm. ~ n~tic propert~
o~ the moulde~ art~lQ producQ~ w~e
- 30
'
:.,
.:,
.,
2~
Br - 5.~ KC and
( 8~ ) xax ~ 7 . 3 MGO~ .
~he magnetE thu~ produce~ ~-r- ac~rnblo~ ln 2S unit~ o~ DC snotor, and
s contlruou6 operatlon taDt for 500 hour~ ~aGt 1 W~ c~rrl~d out.
5 A~ for a ~o~paratlve ~x~mple for To~t 2, the ra~ sterlal h~vlrlg th2 ~an~
compo61tlon wa~ ~noul~e~d ~y an ~n~ctlon ~n ~ m~netlc ~l~ld and a
cyllndr~cal ma~nat of the oUtQr dl8m~ter 32, 5mm, the lnner d~eter 30mm
and the length 6m~n wa~ ~oul~a~ m~gnetlc property of the Dloulded
article produced was
sr ~ 5 . 7 KG and
B~) max ~ 7.0 MGO~.
.''
plece~ of the magne~, were ~ticked by an epoxy type a~he6ive, an8 then
~he outer diameter ond the lQngth we~e made at 3;2mm and 22mm ~y a cut:tlng
f abric~tlon .
. '
15 ~he m-~net~ w~re ~ d ln 2S unlt6 o DC motor and the 500 hou-
contln lous oporatlon wa~ carrlo~ out a~ ~a~e ~ ~e6t 1. ~h~ te~t re~ult~
wera ehown ln ~la 1.
' -
;~
'
DC Motor T~te~ D~ Motor ~xhlblt~d
a D-tQrlor~o~ Pro~rty
~ .
~ - 31 -
... .. .
- 2 ~ . ` .
~e~t 1 t Example ) 25 0
~- Tect 2 ( comparative
-~ ~ example ~ zs
In the ~ 1, thoa~ of whlch th~ mo~or ~howQ~ a ~c~rior~t~d property
, 5 w~re ca8e~ that ~-h~ rotation of t~ motor ~to~Q~ or the tor~ue wac
: ~roppod due to an ~n~u~f~ci~nt ma~n~tic flux ~vailable by ~ d~ln~nation
:~ .
~t tho adh~lv- ar-a of th~ m~n~t~ ~t~cked.
~onsequently by ~n appllcat~ on of the magnet o thi~ vQntion, a
rellab~llty o~ the motor c~n ~e lmprov~d.
.
10 ~:xarnple 2
Raw material~ to mahe a compo31tlon ~3 Fe~2 7 ~ ~3 we~e molten, were C-
c~6~ed and a quenche~ ribbon wac prQpared ln ~n ~rgon atmo~phere by u~l~gc-
a qu~nchl~ ~nd a ribbon rollin~ m~c~ine fro~ t~Q in~ot obtalned. ~he
;. quonehe~ ribbon wa~ coar~ely crush-d, ~a6 ~har~6~ ~n a mould an~ a high
15 t~poraturQ procc mouldln~ wa~ p~r~orm~ b5r applyin~ a pre~au~ o 20
Kg/mm2 for a ~hort tlme t 700 - 800C ln an ar~on atmo~pherc en~lty
of th- con-oll~at~t art~el~ w~e ~lmo~t 100%.
~,, .
eon~oll~atod artlcl~ w~ ln ~roc~ wlth ~ hi~h ~m~eraturQ
~rQ~e ~oul~ng ln ~ v~rtle41 ~lrsetlon to the flr-~ ~ro~n~ ~lrection
;, 20 wlth ~ pr~ur~ o~ 10 X~mm2 at 7Q0 - ~OQC ln an ~rgon atmoeph~ro.
~"
~` ~ trl~ely lt wa~ tr~t-~ wlth a dl~ t~
,
,
s 3 2
' ' " ' ;' . ' ~' :'
' ` :. ~
. 3
A bulk ma~n~t o~t~ln~ wa~ cru~h~d tc m~e a ma~netic powd~r of hn
average partlcle ~iz~ o~ 20~m.
~he ma~net~c ~ow~ar wa~ mix~d w~th a ro~ powd~r c~prl~in~ bl~phenol~
A type ~poxy, novola~ type epoxy and vinylbut~ral-vlnylalcohol copolymel,
calclum ~tearate powdQr and s~llca powder ~ ad~tlvec.
The ~atio ln th~ mlxture was the m~sn~tic powder 90 . 3 wt%, the r~6in
powder 9.1 wt% and ths ~d~tiv~ 0.6 wt%.
~he mlxture ~as hne~dod by a 2 roll~r ~yp~ m ~, The knea~ed mixture wa6
~ranulated to an outer dla~te~ of 1 - lOmm granule~ to ma~Q a raw
lo materlal compound and was moulded Ln a cylindrlcal magnet by an ~xtru~ion
macl~lne a6 Eame a~ ~xample 1, and 1~ wa6 cut and was flre~ a~ter a
demagnetization.
~he ~ize of ehe moul~ed a~tlcle wa~ the outer dl~m~ter 22mm and the lnn~
diameter 21mm, and the maçnetlc fleld for the mo~ldln~ wa~ 14 xoe. ~he
m~gnetic prop~rty of the mould~d article obtalnad wac
Br ~ 6 . ~ ~G ~nd
~ max ~ g.a MGO~.
cono~qu~ntly as ~or th~ pro~uotlon proc~ o~ thl~ lnv~n~$on ~ h$gh
~orform~nce ~A~n~t can ~ obt!ln-~ ovQn a Glo~lln~abl~ thQr~o~ett~n~
res~n 1~ us-d.
-
Exampl e 3
-- 3 3 --
.
,
.- : .
- - -
2 ~ 7 ~
A ~a~ne~ic po~der o~ ~n ~ve~e partlcl~ ~lzo o~ lo~m ~as pr~ar~d by ~he
came co~pos~tion ~nd procedure a~ ExamplQ 1.
A coerclve force lHc o~ thls pow~er wa~ ~ XOç. Thi~ sll~d as Powd~r
A.
~urth-r a6 or ~he other kin~ o~ pow~ a~nstl ~ pow~r o f an average
~ize of 20~u~ wa~ prepare~ ~y th~ ~me compo~tlon and proc~dure a~
Ex~mplQ 2, A ~oe~ e orce ~Hc of thi~ pow~ w~ 12 Xoe. ~hlc i~
callod as Powder B.
~ owder A, nylon 12 powder an~ zinc ~t~ar~te powd~r were mlx~d to m~ke a
rat~o o~ 92 wt~, 7.9 ~t% and 0.1 wt~ re~pec ively.
'
Furthe~ PoWde~ J was al80 mlx~ wlth the a~orementlon~d re~in pow~er an~
the addltive to make a ratlo o~ 91 wt%, 8.8 wt~ ~nd 0.2 wt%.
~he6e ~lxture5 were kne~d~ by ~ 2 ~xe~ xtrw lon kna~ng m~hln~ at
260C. The knea~ed mixt~re w~ ~ran~l~t-d to ~ranul~n of an outer
15 ~lameter o~ lOmm to m~k~ a raw ~at~risl com~ound 111, and a
cylin~rlcal m~net was ~oul~ y ~ ~roc-dur~ ~xpl~lns~ ~n ~a~pl~ 1 by
~n ~xtr~ion ~ouldln~ m~chlnæ ~ ~hown ~n ~ure 1.
.
~e ~o~ldln~ m~thod ~a~ th~ c~ tho~ a~ Ex~mpla ~ and the
~t~uctu~e wa~ o th- ~m~ to Flg~lr~ xpl~ln~d ln ~x~ple 1.
- 34 -
:,
.. .. ~
-
: ~ :. . 7 :
::
. :, . . .
;:- :: . :` ` '..... ` :
: .: `
':
- 2 ~,! ~, `
~f a ~urrent flow~ ln the ~l~ctrom~n~tlc coll ~qulpp~d out~ld~ of the
dle, the ~agnetlc flux g~ner~tod flow6 in the arrow H ln Flgure ~i~ce ~t
tend~ to pa~6 throu~h ~ ~a~n-tic ~a~erl~l wlth a hl~h ~gn~tlc
permeabillty.
cons~quently ~ ~adlat~d magnetl~ ~leld ~ g~n~r~ted ln the orientatlon
~ectlon whlch l~ a ~ace be~w~en a magn~tic ~terlsl Z02a O~ ~hQ ~andrel
and a ma~netlc materlal rlng 20~a in~alle~ ~n the outer ~t e. Th~re ore
when a ma~notlc compo61tlon 1~ p~C~n~ throu~h the orlentatlon ~ection,.
i t 16 ~e~n~ moul~Q~ wlth a pro~e6~ of an ~rlentation of the magnetlc
powder.
Furthermor~ a ma~netlc field with ~ reverse dlrectlon to the ma~netlc
field in the orlent~tion ~ection ie generatQ~ ln a space betwee~ the
front end of the ~andrel and the yo~e 110 o~ the coll, Ther~fc:~e a
demagnet~zatlon of the moulded article c~n ~e achieved by making the
magno~lc fleld O~ thlc a~ac~ a~ a Buit~ble ~tr-ngth wlth an ad~ustment of
a di~tance betwe~n the mandrel an~ thQ yoke 110.
n thi~ ~xamPle, tho m~gnætlc flel~ for moul~ing w~ ~4 XO~, the
t~mpQr~tllre of the~ at th~ mo~ldln6 was 250C an~ 1:ho cooling w~
~ppli~ ~y a or¢e~ alr ooolln~ to th- outl~t ~ctlor of th~ dlo.
20 By tho abov~, thQ orlentat~d r~w matorl~l co~ound 111 ~6 rnould~O. by ~n
~xtru-lon w~h a ~olldl~icatlon wlth coolln~ at th- outl~t o~ th- ~le. A
strQn~th of th~ a~ne'clzatlorl m~gn~tlc fleld w~ ~d~l~t~d to almo~t the
~ ~5 -
- , . .
.,, - . ~:, :. . - -
~, - ' , '
. , ' . . . '
. ~,. .
;. -, .
2 ~
6ame to the coerclve force l~c of the maonQtic ~owd~r ln the moulded
a~tlcle .
~he ~1ZQ of the moul~d art~ cla w~ the out~r ~l~mo~ar 30m~ an~ the lnner
dlameter 29mm. In T~le 2, 6~r~ce ~agnetlc $1Ux ~enci'cla~ for c~se~
5 Teæt 3 and 4 ln which the ~ema~net~zatle~n wag per~o~m~, and ~or C~ICOB
Te6t 5 ~nd 6 wlthout ~he ~ema~nQ'clzstio2~ ~nd chown.
Ta~lQZ
Te6t 3 Example A 20
10 Te6t 4 Example ~ 35
~e~t 5 Colnparative
exsrnple A lS0
.Te6t 6 Comparative
. example ~ 220
15 Ex~mple 4
A m~netic pow~er o~ ~n a~Qr~go pa2~t~ ClQ ~lz~ lO~m ~nd iHc ~ Xoe ~
propare~ ~y tha B~ e compo~it~on an~ E~rocQ~ure ~ ~xaa~~ hic pow~r
1~ c~ d ac Pow~r P..
P.c for th- othor kin~ oi~ pow~r, a ~gn-tlc ~o~r o~ an av~rag- particle
~$z~ 20~1a an~ ~ co-rclve ~orc4~ ~c ~2 XO~ w~ ~r~par~ by the ~e
'~,
:;
~ - 36 -
:',
.
:: -
.. .. .
, ~ , ... . .
~,",' ' ~ ' - ' ' ~ . . ,
composition ~nd p~o~dure a~ Example 2. ~hl~ ~owd~r 1~ c~lled ~ Powder
: B .
.
B~ma to ~xa~pl~ 3, the Powder A was mlx~d wlth nylon 12 po~der ~n~
zlnc ~te~rate pow~r to mak~ ~ ratlo of 92 wt~, 7,9 wt~ ~nd 0.1 wt~
. 5 re~pectively.
Pow~er B wa6 ~180 ~ixad wlth th- ~or-m~ntlon~ r~ln po~er and addit~ve
to ma~e a ratlo of 91 wt%, 8.8 wt~ and-0.2 wt% re~pect~v~ly.
,
The~e mixture were ~neade~ by a 2 axe6 ~xtru~ion kn~ading mach~ne at
. 260~. The knea~ed mixture wa~ ~ranul~ted to granule~ of t~e oute~
dia~eter 1 ~ lOmm to ma~e a raw mat~lAl compound, and a cyl~n~l- ca:
magnet was moulded by an extru~ton mouldlng machine.
. ' ' ,
~he mould~n~ method 16 exp'ained in accord~nce w~th Flgure 3.
.. An extru610n mouldln~ maehine of Flg~r~ 3 1~ compo~ed of ~ cim~lar
. constitutton to ~n ~xtru-lon mouldln~ ~ch~ne cf Figure 1, ~nd an
: .15 ~l~ctromeg~t~c coil 109 i- pocitlon~d out~ldo a dl- to char~e a m~qnetic
. ~l~ld in th~ al~, but th-re 1~ a ~f-roncs le ~n ~l~ctromaqn~tic co~l
for demagn~t~zatlon 1~ lnstall-d ln ~ront o lt.
,
~h- ~or~mentlon-~ ~ranul~t-~ raw matcr$~1 com~oun~ 111 wac ch~r~e~ ~n
t~ ~x~ru~lon mouldln~ m~ahin-. ~hQ r~w mat-r~al oompoun~ 111 wa~ h~at~
~t 2~0C ln th- ~ylin~r 102 to m~k~ lt l~ a ~luid~z~ 6tat~, ~nd ~ wao
p~c~d throu~h the di~ 105. ~hs dl~ uctu~ W~8 the ~am~ xplaln~d
- 37 -
'':
. , . . . ::
:- . ~ ~ . :: . .
. . , ~
2 ~
~n Example 1. Accordinq to thl~ ~nv0ntion, when the magnetlc COmpO~itlO:;
t~ p4~ed through the orlentatlon ~ectlon, lt 1~ ~oulded wlth ~ prog~c~
of an ori~ntation of thQ ma~ne~ic pow~Qr ~a ~ame to Exampl~ 3.
~ n thi6 ~xample, thQ mag~etic flel~ for mouldlng W~B al~o 14 KOe, the
temperature o the ~le t the moul~lng wa~ 250C, and th- coolinq wa~
given ~y a force~ alr coollns to the outlet cectlon o~ th~ ~le. Tne
orient~ted r~w material compc~nd 111 was moulded by ~n extL~lon by a
~olldificatlon with coolin~ ~t t~e outlet of the die.
The demagnetlzatlon W~6 carrlet out ~y genexating ~ magnetlc fleld for
the demagnetlzatlon by turnlng on an ~ttenuat~ pul6e current ln the
electr~ma6netic coil 113. The ~trength of the ma~netlc field for t~e
demagnetization w~s 30 KOe, ~nd lt wa6 atten~ated with ~0m ~ec. ~h~
ma~netic fie~d ~a~ gen-rated ln the electromagnetic coll 113 ln every 15
~e~, and the dem~gnetization wa6 carrled out con~inuouEly~ The s~ ze o~
the ~o~lded art~cle wa~ the outer dismeter 3~mm ~nd the inner clameter
2gmm. Surface ma~netlc ~lux d~n61tiec of the moulded artlcle6 fcr ca~
~n whlch the d-m~net~zation was pe~formed (Tost 7 an~ 8) and or ca6e~
-without the demagnetl~atlon (Teet 9 and 10) are ~ho~n ~n Table 3.
~ ahLe 3
; 20 . ~9~g~
: ~e-t 7 Ex~mple -~A - lO
T-~t 8 Ex~mplQ ~ lS
Te6t 9 comp~r tlve
- 38 -
.,
:
,
;, ~ . . . ~ . . . . . , . . .
,,. -, --. : ... .. .
. . . . , - , . , ~
2 ~
exampîe A ~50
Te~t 10 Comparative
example B 220
A~ lt i 8 clear ~ro~ T~ble, the ~Ur~ac~ ~agne'clc ~ x den~lty whlch
5 remains ln the ~o~ulde~ art~ cle could be dropp~d at 6 ~% by an
applicati on of ~he prc~c~so o~ thl~ ~nv~ntlo~. c~n~ec~ ntly th~
~orkabillty at the cu~tlny ~'cep, etc wa~ ~reatly lmproved.
~xample 5
A magnetlc Powder A or Po~der B ~ the 6ame compo~ltlons to ~xa~nple 1 and
10 2, and Ro6~n a ~a thermo~ettlng epoxy ~e~lnJ or Reeln. b (a thermoplaEtlc
l-e~n ~'on lZ~ we~e weighed to nlake a de~red vo~ume ratlo, were mixed
and a sheet E~ate compound Wa~ prepared by ~ne~ding the mixture by
~assin~ lt th~ou~h a ~ap of a twin roller mill ~epeatedly after cha~:~in~
it ln the m~ll.
:~ .
15 ~he kneadin~ temperature o~ the mixtu~Q ~6 at 90C when R~in a wa~ u~d
and at 250C wh~n ~e~ln ~ wa~ u~e~.
Th~n thè compound Wk- c~u-he~ ~nto p~rt~ Cl~B and w~ moul~ed by an
~xtru~lon by pa-~1no throush ~ cyllnds~c~l ~10 by char~in.~ lt ln a ~erew
type ~x~ru~lon mou1t~ng m~chlne~
, _ ~9 _
' ~ ,
, ~ ~
. :
2 ~ _ . ,. L ~ ~
A ~arrel temperature o~ ~he ~xtruslon ~oulding machine WA8 at 13~c ~c~
Resin a and at 250c ~or ~esin b an~ th~ die temperatu~e w~ the rnould1ns
temperat~lre for thQ ~ach ca~e.
~he ext~u6ion tate wa~ 1 mm/~ec.
~he outlet te~per~tur~ of th~ ~ie w~ get ~t ~ ~olldl~c~tlon temperature
of the compo~ltion moul~ed. Thl~ temperature ~l~fere~ by th~ proce~6ec.
Re~ln a wa~ u6ed ~or Proce~ 1 and Procesc 2, Proce~s 1 wa~i ~ process to
make ~he ~olidl~lc~tl~n wi~h coolln~ at the outlet o~ th~ dle, an~
~roces6 2 w~ a proce~6 to make the cure by heatlng at ~he ~ont end of
lo the die. Proce6s 3 was a proee~ to. ~olidify w~th coollng at the outle~
of the die u~ing Resln b. The magnet6 thuE produced were cut by m~tho~
~hown ln Table 4.
: ~ab~ 4
, ~Q~
15 CUttin~ Method 1 Cuttln~ by melting wl~h ^ h-~t~ wlr~
2 Cuttlng by ~ ~uillotln~ cutter ~ystam
3 Rotatlon ~aw tooth -y~te~
~mon~ tha~e, Cuttln~ M~thod 1 w~ cuttlng ~tho~ ~ thl~ lnventlon
wh~eln a curr~nt 1~ turn-~ on In a ni~rom~ wir- of a ~am~tor or 0.2mm,
lt i6 contacted wlSh ~ ~a~n-t when lt 1B h-3te~ b~ the r~ tancQ ~nd thQ
ma~net 16 cut ~y meltlng wl~h heating.
.:
:: - 40
- ;
. .
' ~' , .' : '
:~
.
,
- - - -
2 ~
Re~ult~ of the cutting, when th m~vne~ produc~d by ~n~ae prsco~es WQre
cu~, were shown ln Table 5.
In th~6 te~t, the magne~ out wa~ ~ c~lln~rlc~l m~gn4t wlth the o;lter
diameter 30mm and the lnner dla~et~r 2~mm, And th~ volu~e ratlo of the
m~netlc powder wac 60 vo~%~
s~
Although the m~netic Powder A and ~ were u~, both ~howed th~ ~ame
re6ult6~
cutting Me~hod 1 excellent 600d ~xcellent
2 b~d ~ad bad
3 or~inary excellent excellent
~he ma~net of Proce6~ 1 waC ~he mo~t ~l~flcult ~ample to cut am~ng the
magnet~ o Proce6~ 1 - 3 becau~e lt was the mo~t br$~tle. AR it ~8 cl~ar
from Table 5, th~ cuttlng method 1 ~nd ~he çuttinC metho~ 3 c~n b~
~r~ot~cQ~ ~or cutting tho~e ~agnot~, ~nd it la not po~ibl~ to cut lt ~y
thQ ~utt~ng mQtho~ 2.
' . .
Exa~le 6
N~xt, r~ult~ o~ cuttln~ when thickn--~ of t~e ~a~not to be ~ouldQd w~
chans~d, were ~own in ~able 6.
. .
. . . . .
~ ~ .
.- . , .
~ ,
2 ~ ?7~r ~
The ~nagnetc rhl~ tlma h~lt an outQr ~l~m~ter o~ 30mm, W~iB Q cyllndrieal
ma~net ~nd the m~ Q~ pr~parad by Proce~ a~ u~od, The r~aults cf
either the tnagnetic Powder A or ~ w~re the samQ.
~L~
S Th~k~L~
Cutting M~thod 1 good excellent excellQnt exoellen~ excellent
CUttlng Metho~ 2 I-xcell~nt good ordln ry ~ad bad
As one of the ~atures of ~he extru6 lon moul dlng method, it csn be
10 enume~at~d that a thin thlckn~6~- m~net can be moulded. There~ore i t
lmportant to cut a thln thlckne~ magnet.
Tn case of the cu'ctin~ Method 3, lt was ~if~loult to cut lf the. ~hl~:kne6
of the magnet boca~e O . Smm or lel3~, and it was not po~ le to cut wher~
:; it wa~ O . lmm ~u~ to ~ format~on o~ craekin~ .
; 15 On the oth~r hand, ln c~ of the Cuttlng Method 1, a thin thlc~nes~
ffl~n~t Clln b~ cut ~inco no xco-~ ~It~B 1- appl$ed to th~ net at th~
cutting ~tep.
,
Con~quently it ~ o~ar that t~ cu~tin~ by moltlng. ~lth ~ ~e~tad wl~
i~ an ed~ta~ 'cag~ou~ mothod ~!or th- outtlnq.
~x~mple 7
- 4~ -
.. . ..
... . , . ~ . .
',: ~ . : . .:
-: . . : . . .. . . . .
. ;J;
Re~lt~ or the cuttin~ whon the volume ratio of th~ m~n~tlc powder w~
chan~ed were ~how~ ln Table 7.
The maqn~t cut thl~ tlme ha~ the out~r dlnmeter of ~Omm ~n~ the lnner
diam~te~ of 29m~, w~ a cylindrical ~n~t pr~pare~ ~y ~roce~ 1. ~ne
magnetic powder uoed WA~ the m~gnetlc ~owd~r A
~ Q ~ 70 72.
cutting Method 1 excellent excell~nt excellent e~cellent good
lo Cutt1ng Method 2 ordlnary ordina~y bad bad ba~
A6 the volume ratlo of the m~netic powder lncrea~e~, the volum~ rat1c cc
; the resln ~crea~e~ accor~in~ly, and the b~ndlnq ~tren~th ~f the ;-es.n r~
the ~aqnet~c powde~ dropG.
~h~r~ore th~ m~gnet mouldet becom~ brlttle ~ the m~gnetic powder
ln~roa~e~. ~hlo tren~ i~ r-mar~a~la ln a c~ce o a~ uncur~d ~ne~
produoe~ by Proc~ 1. A- tho volu~Q ra~-lo o~ tho m~n~tic powder
lncr~Q~2~, the m~ t por~orm~nco of tho ~gnat 1~ Lm~roved, and
~h~r~fore lt 1- ~mportant th-t thQ cuttlng c~n ~ rl-~ out eve~ in
ca6e o~ larga volu~- ratio of th~ maonQ~lc ~owder.
.~ ~
20 ~n c~-e o~ Cuttlng Metho~ 3, the eutting could not bQ ~r~ctlc-d whQn th~
volu~ rat~o o~ th~ ma~ne~ic powdQr lncre~ed.
-- 43 -
on the othel^ hend, ln c~ce of Cuttlng Method 1, the cutting can be
carried out even the volum~ rati o o~ thQ magn~tlc powa~r i. 72 vol ~ .
P~ccordlngly, it 1~ clear from th~ re~ul~c~ t~l~t cuttlr~ Metho~ a
6u~er~0~ method ~or the cuttin~ o~ ~ magnet of ~he ~xtru~ion.
s Example 8
An uncur2d cylindrical D~agnet wa~ produced ln ~cor~ance w~ tll ~ollowir;~c
to use lt for a curin~ unit o~ this inven ~on.
,~o
At fir~t, 60 vol % of a magnet~c poWder of Sm - Ci~l~amily magne'c and 40
vol % o~ a the2mosettln~ rQ~in nlainly comprl~lng.an epoxy xe~in were
10 mlxe~ as~d a co~pourld wa6 prepared by kne~ding lt w~th a -~ller
The epoxy re~ln u6ed had a thermopla~tlc re~ion of 100 - lgO~ ln W~
" .E vi~cos~ty s~ddenly droppe8, and it was cured at a tempe~ at.~re cf
200"C.' .
The cornpound p~epar~d wa5 then co~r--ly cru~hed aslt it wa~ char~e~ i n a
15 mo~llt~ny machlne.
AB or the moul~ mach~n~, an ln~ctlon ~oul~lng m~chin~ and an
extruslon moul~ln~ m~chlnQ coul~ bQ ~ed, but thQ ~xt~wlon mouldin~
mach~nQ w~o u~ad h~re. Th~ ch~r~-d compound. wa6 heat~d ~t 100 - 150C in
th~ moul~ln~ nla~hlne to ~ke lt ln a moltQn ~tat~, th~ m~netlc powder
20w~ orienta~sd ln a dl~, th~ ~ol~en mlxturo wa~ ool~ w~th ~ool~ny
; ~ - 44 -
~ . .
., . ~ . ~...... . . . ::
. . . . .
: ' ' ' ' ' '
2 ~ ~
ac ~t~ 6tate snd ~n uncured cyllndrlcal magr,et w~s prop~red ~fte~- a
demagnetlzation.
The ~ize o~ the ~a~nQt wa6 ~he out4r ~la~er 32,emm an~ the ~nner
dlameter 31.8mm, and lt wa6 cut ~o make ~t6 leng~h ~t lOOmm.
~n Table 8, ~ co~parlcon of varlou~ curin~ pro~-a~#~ ~e~t ~1 - 13 ~or ~he
aforementlon~d uncured cylindrlcal ~agnet 1~ ~hown.
Ta~le_~
Sha~e ~ ~o~t
~est 11 excellent ~ood good
10 Test 1~ exceilent cr~inary ordinary
Te~t 13 bad excellent excellent
~e~ the rec~lts o the curin~ proce~ of thl~ inventlon for ~
cylindrical magnet. Na~ely the ~utor circum~e~enc~ of the uncur-d
cyl~n~rical ma~net ic fi~d ~y,~n ~laeti~ m~terl~l, ln t~l~ ca~e lt ~as a
~llleone rubber (her~inaf~r e~ an $nnQr body) expan~e~ wlth a gac
~in thia ca~e it w~s air), ~n~ it 1~ eur-~ by hoatln~ ln an oven.
Te~t 12 1~ a conventlonal p~oc~ ln ~Yhlch th~ out~r clraum~r~nc~ lo
fixH~ with ~ o~tlon unl4 ~ attashQ~l to the ~, and lt 1~ cure~
by heatl~g ~ith ~ rotatlon ~n th~ c~re~ r~ntlsl ~lr~tlon. T~t 1~ 1
20 ~ pro~ to cur~ thQ cylln~rlcal magnet by h~atln~ by pl~ln~ it ~n an
o~rer. ac it ls without thç ~lxing.
- 45 -
-
.
~; ~
~. .
2~
~h~ the~moCUrln~ con~i t~on here ~a~ oooc for one hour~ ln N2
atmo6phere, ~h~ eh-pe in Ta~le w~ t~e shape o~ the ~gnot after the
cure.
In case of Test 1~, the m~gne'c aft~r the cure 1~ comPl~ltely doÇormed and
5 it ~ obviouc thdt the flxlng of the Gh~pe lo n-c~s~ t the
thermoeuring Btep~ On h~ other hsn~, ln ca~es th~t ~he sh~pe 16 flxed,
the cyllnd~ic~l form $~ n~rly Xe~, and thUB ~e~t 11 and Tes~ 12 ~re
u~eful prooe~6 f~om a vlewpolnt o~ the ~hape.
The operability mean~ an e~alnes~ o~ the operation of the U21it and lts
capability for procQ~sln~ a lar~e ~mount of the ~ampie.
In ca~e of Te t 1~, it ta~e~ more tlme for an oper tlon to conn~ct t~.e
~ig h~lth the rotat1 on unit than an operatior. o ~e~t 11 to ln~ert the
inner bo8y when compar~d wlth ~st 11 o~ thl6 invention. ~urther~ore
from a v~ewpo~nt o~ co~t, Test 12 16 mo~e costy ~cau~e of the
15 requi~ement of the rotation unit. conBequ~nt~y the T~t 11 pro~e~ a
superior proces6 to Te6t 12 an~ 13.
Next the aimen~lo~ acc~cy ~t~r tho cur~ whQn 1~ 1~ cura~ by hQntlnq by
:~ ~e~t ll and ~e~t ~2 ~- ~ho~n in ~akle 9.
rrect 11 a.oo~ o.o
- 4 6
'''
. ~ . -- . . . . -
- - - . .
.:
- : : . -
2 i, ~ . . . ^ ~
Te6t 12 0 . 07 0 . 04
8efore the cure ~ . OB O . 05
t Un~t: mrn ~
The rotation rate of ~e~ hQre wa~ ~oo rpm. ~c io the ~.~ximum ratQ
: S which can be practic-d by tak~n~ the eoa~t lnto con~i~er~tlon.
~he alrpres~ure of the inner bo~y o~ Tes~ 11 W8~ 1 at~.
The ma~net before tha cure wa~ prep~r~d ~y ~omewhat ~ecrea6in~ it~
d~mQ~lon accuracy ln order to chQck a corr~Gtlon ~bility ~ the
dimen6~0n by the cur1 n~ proc~s~ by heatlng .
10 From Tabie 9, it i~ under6tood that the dirnen~lon nccur~cy in corre~::ted
by the curing pro~e6~ by heating 6uch as 'rR~st 11 ar,8 Te~t 1~.
Thl6 iE becau~e th~t ln ca~e of T~6~ 11 the ~lr ln the ~nner body i8
expar.ded in the atmocphsre ~ the th-rmocurln~, lt a~Plie~ a ~orce to the
~sgnet reculttng the correctlon of th- di~n610n of the magnet while it
. ~5 $~ ln a ther~oplactic ~tate.
P~8 ~or TQBt 12, a ~ntr~ ~u~ orc~ g-~erat~ by th- rotati on h~ a
~imllar Astion, but tho dlmon~ilon ~ccus~y by th~ corr~et~on o~ t 1.1
i~ ~urth-r $mprovQa..
Thi~ ecaU-Q th~t th~ forc- l~y ~xpan~l~on o~ the ~ir 1~ stron~er thsn
20 th~ centrlfu~al ~orcQ r~ultlng ~et'c~r correctlon o~ 'che dlmen~io~. From
,
:
::
:
2 .~
the cor~ectlon abll~ty os~ the tlmen~lon, ~ o undQr~tood the
proce60 o~ Tec~ 11 of ~hlG invention ~ uperior.
Example 9
~a~ materi~l~ to ~-ke th~ ~an~e co~po~ltion ~ ~ow~r ~ in Exampl~ 3, s~,
~C0 0.6~2 Cu 0.0~ Fa 0.~2 Z~ 0.028) ~.3S wero molten, ~n ln~ot producc~
wa~ magne~cally eurad by a he~t tr~atment ~ter casting, and a m~netic
powder havlng the a~r~ragQ p~ clQ ~ize o~ IO,um and tha co~roive orce
~sc of 10 xoe w~- obt~lned by cru~h1ng ~he 6aid ln~ot.
The powder wa~ mixed wi~h nylon 12 powder ~n~ zlnc ctearate pow~e~ tc
lo make a ratio o~ 92 wt~., 7.9 wt~ and 0.1 wt% as ~ame to Sxample 3.
The mixture wa~ ma~netized by ~ pul~e magnetizatlon ~mit showl~ in Fi.g~:re
:1 4 with usln~ a magn~:tic field of 2~KOe, and it w~ then kneade~ by b :WC
axefi extr-~ion k~eadirl~ machl2lo~. ~~
.~ ,~
~n Figure 4, 301 1~ an electro~agnetic coil, 322 i~ a pulse C~tl r-rlt
n-ration po~or ~ouroe, 303 1~ ~ table to a~u~t a hlg~ht of a ~mple ~nd
305 1~ a raw ~t~rial m~o2let~e powd~r,
' . .
Tho l~r.o~d ~lxtur- ~a~ sr~nulate~ to partlclo~ o~ th- out~r dl~ter o~
m to ~aX~ ~ raw mat~r~l compound., an~ 6 cylln~rlcal ~a~n~t wa~
moul~d by wing th- extru~lon ~oul~ln~ ~achln- ~hown ln Irl~ur~ d th~
dle ~hown ln Fi~urQ 2 wlth a ~a~- ~roc~ure ~crlb-d ~bove,
.~ , .
- 48 -
--. . .
, . . .
, .....
. . . , ~ . .
.
- .. . . .
?~
~n thls ~xa;nple, tha die temperature st th~ mould~ng wac 250C, ~nd a
cooling was carrl~d out by a forcad ail- cool~n~ at the outlet o~ th~ d~e.
Ac~ordlngly, an orl~ntated raw mat~rlal co~pound wac moulded by
extru~lon by a ~olldiflcat~o~ with cooiins at the outlet o~ thQ dle.
S The ~lze of the moul~e~ art~cl~ wa~ th~ outer ~iamator 33mm an~ the lnner
dlameter 32mm,
In Figure 5, a comp~L~i~on of ch~n~Q~ o r~ ual ma~netlc fluX de~sity
~Br) with magnetic ~i~lds ~or mould1ng ~o~ ca~e6 wlth ar.d wlthou~
mag~etization of the rs~ ma~teri~l pow~er be~o~ the mouldinq i~ showr..
10 Fron~ ~igure 5, lt i~ understood th~t a magnet w~th ~ hi~h Br le wi th
high degree of t~.e orientation can be prepared by an a~optior. of th~
magnetizatlon for the pow~er prlor to the moulding evQn l the ma~llet~
fiQld ~or the mouldlng 1~ low.
~usthermore a6 ~or the m~gnet p-~ormance at the hlgh magne~ic i-1d
ound 15 KOe) ~or ~h~ moul~lng, the ca~eR with the magnet1zat~on ~how~d
high~r value~, ~nd it wa~ un~r~tand. that the m~gn-tlzatlon ~o~ the
pow~2r pr~or to ~he mouldirl~ h~d A ~ Qr ~f~ct.
.
Ex~mple 1 0
Raw mat~rial~ w-ro molt~n to m~Q a Compol~1 tion o~ ~ 0 . 5 Pr 0 . S tco
0.672 CU 0.08 Fe 0.22 Zr 0~02a) 8.3S, an in~ot produc~d W~ ~a~netic~lly
- 49 -
.~..................................... .
.
:. ~
- - .
- ' ` .
cured ~y a heat treat~nt a~ter c~tin~, and maqn~tic pow5ar~ h~vlng a..
average part$cle ~lz~ of ~o~m were obtain~d by cru~hln~ th~ ~ald lngot.
2 kind~ of the ~hgn~tlc powder~ havlng the co~rclvQ ~orc~ IHe 7 KOe and
10 XOe re~pectiaelY wQre prepared by chançlln~ a conài Oion o~ the ~,~a_
5 treatment.
The6e powder~ were ~ix~ wlth nylon 12 powt~r an~ zlnc ~t~arate powd~1 to
make a ratlo of 92 wt~, 7 . 9 wt% and 0 . 1 wt4 re~pectlvely.
The6e magnetlc powder~ were maslle~clzed. by u~ ng a d~ rect c-;rl e:~
electromagnet uni~, and then ~he~ were kneaded by a two axe6 ex~ruff lon . .
10 X.nead~ ng machlne at 260c .
- '. .
~he kneaded mixt~;res were granulated to p~rtlcle6 of the outer ~amet~
- lOmm to make a raw ma~ial compound, ~nd were mouldod by an extru~iior.
lntc ~hln plate state ma~net~ by ucin~ a dle Eh~wn ln Flgure 6.
, ' .
~n the die 401, wh~n a c~lrrent i~ turned on in ~n ~lo~tronlaçnetlc coil
15 403, a ma~natlc ~iel~ v~rtic~l to the pa~ge of a com~oun~ ~n the dle ln
genoratlad b~tween tha u~D~r and the lowor ~ol~ pi~ac~ 404. ~hor~fo~a
thln plate ~t~t~ ma~net haY~ n~ an orl-nt~tion o~ the ~agnet~ powder to
the thlckno~e ~lrectlon ~ molul~-~. By th- way, 40~ i~ a ho~ter.-
,
~rh~ ~12e o~ th- mouldO~ axtlcl~ wac t~ ~ wl~th o~ 60mm ~nd th~ ~hickna~
20 of lmm, and the ~t~nsth of th~ ~açnetlc field at the moul~ing wa~ 12
Xoe .
- 5G -
......... ~
.. :-
: : - : . , . .. :
::;.~ , . . .
:. , .
. :
In F~ure ~, a relation between th~ 6trenuth of the ma~netlc ~lel~ ~o
the magnetizatlon prlor to the mouldlng, and the resldusl ma~netic flux
~en6ity of the moulde~ ~rtlcle 16 ~hown.
~rom the graph, lt wa~ understcod that though thQre W~B no efect o~ the
ma~net$zation prlor to th~ mouldln~ lf ~t wa~ ~one ln a ms~netic 1e;~
which was weaker than the coercive force of ~he ma~netic powder, there
was an ef~ect to improve th~ magnetic performanc~ 1~ lt ws~ done ~.r. a
magnetic ield stronger khan the coetcl~e~for~e.
- : ,
~xample 1'
lo P.aw materlal6 were molten tc make a compo6itlon of Nd ~3 ~e ~2.7 ~ ~.3,
: were ca6ted, and a quenched ribbon was prepared in al~on at~o~phere hy
nq a quanch$nq ~nd rl~bon rollln~ mach~ne for the lnqot produc~d.
Th~ quenched r~bbon w~ coar~ly crush~d, lt wa~ ~illed in ~ mould ~r,d
.~ hiqh temp-rature pre~ moul~n~ wac carr$o~ out ~n ~rCon ~tmo~h-re . at
. ~ ~ 700 - eoooc wlth a pro~sure o~ 20 Kg/cm2 for ~ ~hort tl~eO
The ~on~oli~t~ artlclo obt~ln-~ had a den~lty ~l~oot 100~. ~h-:
aonfolld~tod ~rticl~ o~tain-~ wa~ moulded a~ain by th~ hlgh t~mper~ture
~ p~O~4 mouldln~ in a vertical dl~octlon to ~he lnl~lal prQ~-ing ~lrectlo~
.;
,' ' , '
.
, ~ '' ' '
. " , . ~;
., ' ' " . ' ' ';
in argon atmo6ph~re 6t 700 - ~00~c wlth a 1~ x~/m~2 pr~aure INamelY,
dle ~p~et wa6 carri~d out).
A bulk 6tate ma~nQt obtalned wa8 cru~hed ~nd 9 ma~netic pow~r o n
Average part~cle ~izo of 20~m wa~ obt~lned. ~he co-rcive force o~ ~he
ma~netic p~wder w~ 12 KOe.
The ma~netic powder w~ mlxed with a r~inlng pow~r comprl~ln~ blsphenol
A type epox~, novola~ type ~poxy and v$nylbutyr~ nylalcohel copol ~r,~
calclum ~tearate powder ~nd 811~ ca pow~er ~ ~dditi~es to make a ratlo
the magnetlc powder 90.3 wt%, t~e r-~ln powder 9.1 w~ ~nd the addltlve
10 O, 6 wt~ respectiv-ly.
' :
The`mixture wa6 ma~netlze~ wlth a 35 XOe magrletic ~leld by u~ing ~ p-tl~e
magnetization unit and it ~as kneaded by ~ 2 roller type mill 2~ 91)~.
The kneaded mixtur~ wa çranul~ted to an ot~ter dlamete~ of 1 - 10m~.
~ranul~s to make B r~w materlal compo~nd an~ wak moulded ln a cyl~n~ric~l
ma~ne~ b~ an extru~lon m~c~lne ~ ~ame a~ ~x~mple g,
.
In thi- ExaDple, tho ~- te~p-ratur~ at the ~oul~in~ wc~ 140C, and th~
6tren~th o~ th- ma~n-tlc ~l~ld ~o~ tt~ ~oul~ino w~ a xo..
The ~lze o~ th~ ~o~ld-d ~tlcl- wa~ th2 out~r dl~m~t-r ~ nd the lnner
di~eter 6mm. m~ mouldod ~rtlcle w~ cut ln a ~ult~le length, ~a~
. . .
20 ~ma~notiz~d and w~ r2d ln con~ltlon~ o 200C x 45 ~inutes.
,
~ 52 -
~.
~- . ' '
, ' ' ~ -
' ~`' ~ ' '''' ' ' .
~hQ m~netic proporty o~ th~ moul~a~ artl~le~ o~t-lne~ Q~t 13 - 15 1~
6hown ln Table 10. ~e~t 14 - 15, the eo~np~r~tlve x~mpleJ we~e a
magnetic prop~rty o~ ~ampl~ moulded wlth th~ ne~ic fi~ld ~or th~
mouldlng ~t 8 Ko~ without the ma~netizatlon prlor to th~ moul~lng (~41S-'
14 ) an~ a ~ample m~gnetlc proparty mould~d wlth the m~ tlc fiQld fc-
5 the ~nouldin~ at 15 KO~ ~nd a dle of whlch thQ orlent~tlon ~-ctlon at th~
front end waa shorten~ (Te~t 15).
;t",~,Q
: .
. (B~) max
.," ~iL (~
-~est 1~ 7.0 ln.4
Te~t 14 4,3 3 5
~e6t 15 5.1 g,g
,'' .
A~ lt i6 clea~ ~orm ~able ~0, almo~t no ori~ ation 16 ob~erve~ in a
t~ ~ comp~rative example Te~t 14, ~n~ the ma~net obt~ined m~rely ~how~ a
, ~ 15 pcrformance cloc~, to an lEotroplc one.
~ I
on tha contrar~r ~ hloh per~orman~e ma~net wlth ~ u~ficient oriont~tion
o~t~lne~ ~y thia Bxample.
.; .
n cac~ of ~re~t 15, the ~gnotic prop~rty la low ~n rplt~ of lt- hlgh
~gr~Qtic field for tho mou~ v~ d lt io con~ r~d th~t ~ ~uf. ~clent
20 or~ent~t~on of the mel~netlc powdar 1~ 2~0t ntt~ln-~ ~t th~ moul~lng ~lnce
th~ l~n~th of the orlsnt~tLon ~-ctlon ~ecomeo extr~m~ly ~hort ~uch a~ lmm
.. .. .
I: - 53 _
., '
"~'
.. -.. , ~
!
~ rj ~ f' ^ ;'`, '~'
or le6c ln order ~o charge ~ 15 XO~ magn~tic fl~ld at th~ or~entatlor.
sectlon ~ue 'CG itC ~ry ~lne cylindrlc~l ~orm havlrg th~ lnner diam~r
of the moulded ~rticle 6mm.
-
~ herefore a mouldlng p~oo~ of thl~ inventlon ~ ~ very ~ffectlve5 proce~6 for a oa~e in wh~ch a hi~h ~ tlc ~ld ~or ~oul~in~ i8 no'c
a~alned ecau6e o~ ~ llmlt~tlon o~ a mould.~ ar~lcl~ or a ctruc~ual
probl~m o~ a dle.
~xampl e 12
In thi6 invention, Powde~- A and E were prepare~ by the ~ame comp~itic~
10 and ~recedure to Example 4, theY were kneaded with the rcsl~
c~rllndrical ma~ne'~ were moulded by ~n ex~ru~lon moul~ing machine af~er
çlranulating the kneaded mixture to parti~les havlng the outer dlame~ ~r 1
- lOmm ~o make a raw materlal compound. The moul~ln~ proce66 16 k~ie~
~ u61ng Fi~ure ~.
15 An oxtru~lon moul~lng ~chinQ o~ F~gur~ 8 ha~ a 6imllar compo~ltion to
thQ QxtrL~ion ~ouldlng mach~nQ Of ~l~ure 1~ ~owQver, at th~ ~ron~ cnd o~
th~ ~la, 4 ~1QC~8 0~ ultr~on~c occlllat~r (~an~avln typ~) 114 ~r~
ln6t~110d to g~nerete a ~ vlbratlon.
s~
~ e ~os~m~nt~ on-d g~nul~t~ aw mat9rl~1 conlpoun~ 111 w~ ~har~e~ to
20 tho xt~u~lon moulding ~ach~n~ o ~lgura a. ~ho ~aw matori~l eo~pound
was h~at~d ln the cyllnder 102 at 260C to ~akQ lt ln a flu$~i~e~ ~tate
and lt wa~ p~ed throu~h the ~i~ 105.
: - 5 4 -
.
. .
.
-,: .
,
`~' ~' '
2 ~
The die ~tructure wa~ th~ ~ame a~ Flgure 2 xplaine~ 1n ~xample 1.
In this ~xamPle, the mA~netic powder i~ moulded whlle lt 1~ be:r.g
orlentatod wh~n the ~a~netlc co~posltlon pa~os through the o~l~n~atlon
section. ~he ~l~Cht vlb~tion ~rom the ultr~onio o~cill~tor was
transmitted to the ~ront an8 of the die.
, . .
In ~hl~ examplQ, thQ ~asn0tlc fleld :Eor the mouldin~ wac 10 XOe, the dle
temperature at the ~ou~ dinç wa~ 205C and the coolln6 w~ ~p~l~ed ~y a
~ forced alr coollns ~o the ou~l~t of the die. Thu~ t~e orienta~ed ~aw
: mate~ial co~pound wa6 ~oli~lfie~ with coolln~ at the outlet of the dle
and wa6 moulded by an eXt~lOn~ The size of the mo~ldQ~ ~rtlcle wa~ tho
outer dlameter of 25mm ~nd the ~nner dlamete~ of 23mm.
Dlferen~e~ of the m~net performance of thQ moulded artlclo th~ mould:r;g
rate are shown in ~able 11 for ~a6es of an appllcatiDn o~ the s;i~ht
vi~ration (~e6t 16, 17) hnd for case~ o~ no ~pp;'cat~on tTQs~ 19, ~g).
Test 16 snd 17 are th- ca--~ with the ~ ht vibration and To~t 18 ~nd lg
~ ~ are the caoe~ without it.
'"' I~L~
; ' (BH~ m8x Mouldin~ R~ta
," ~a; ~L ~la~l
To~t 16 A - 7.5 2.5
T~t 17 B 10.2 2.0
----~
: 5
, ',
':,"'~
.
.:
, -
:
.~ ..
2 ~
Tect lB A 6.7 1.8
Te6t 19 8 8.S 1,5
A~ lt ~ s cle~r fron T~le 11, Example~ howc ~n im~rovQment on ~cth ~f;~ the ~agnetlc property hnd the mouldln~ rat~. It i~ considered that 1~ icdue to an lmprQyed orlent~tlon by ~cilitatlng e rota~lo~ o~ the mavr,e:lc
powder by the applicat~on of the ~ ht vihr~tlsn at th~ mouldin~.
~urthermore lt can ~150 be ~aid that th~ ~ouldlng rate 16 lmprovod ~y a
reauction o~ the extru~ion re~i~tanc~ by the ~llght vi~r~tlon. ~e
rea~cn of the low ~agnetic~pow~er ~i~ not ~u~fi~iently orlent~ted ~eca~se
. 10 the magnetic fleld for the moulding whlch ~ao able to ch~r~e wa~ only 10
KOe.
Therefore the moul~ing process o~ thi~ lnvent~on is a particulariy
. .
ef~ectlve proces6 for the ca6e in whlch a hi~h ma~netic rield ~or the
moui8ing can not be att8inQ~ ~UOE to hape~ of the dl~ or the mcu:~e~
~S article.
.,' :
~xample 1 3
. ,~ .
~eble 12 ~how~ ho~ much degreQ of thQ thickne~ moul~a~le without a
~o~t~ ricatlon ln e~ch moul~ng ~tho~ o~ ~n oxtrw lon ~oul~lNg m~ho~
e pr~is mo~ld~n~ m~tho~ ~nd an in~oction ~oul~ing metho~.
._ -
.
~ - 56 -
' ~
;
1 ,
~ ?~ r ~ ~
Sxtru~an Moul~ing ~ P ~ P P
Pre6s Moul~lng P P
Injectlc~ Moul8in~ P ~ I I I
PO~ le
~ po~sible
Magnet6 prepared her~ was r~ng sh~p~d w~th the outer dlameter o~ 30mm~
~nd the mouldin~ were pororm~d With the thlckn~ hown ln ~ble 12.
.
The ma~netic powd~r u6e~ wa~ Sm - Co f~mily rare earth magnetic po~er
and as for the ~esin, nyl~n 12 wa~ u6ed ~or the extrus$on mo~ldlng metho~
and the in~ection mouldlng ~ethod, and an epoxy re~ln wa~ u6ed for the
pre6~ mouldi~g method~
The m~xing rat~o of the-ma~netlc pow~er an~ the re~ln wa6 90 Wt~ Wt% C~
for the extrusion ~oultlng method and the ln~ectlon ~ouldln~ mathod, ~nd
g~ wt ~ ~ wt~ ror th- pr~ moul~in~ m~tho~,
~ 6 under-tood ~ro~ ~able 12, tho ~o~ldln~ w~ not b~ able to
p~rform 1~ t~e thlckne~ o~ the ma~notic ~oul~e~ ~rticle becamc thln ~or
. . :
the prQ~ mouldin~ metho~ ~ndl the In~octlon ~nou~lnq m~tho~. ~hlc was
due to a dlf~lculty So fill ~h0 ~a~notlc pow~r ln a cavlty ~ ~ thc
20 th~ ~kneos ~eo~me thln ~or ~ ~a~- of tho p~ noulO.lng ~ethod, and 1~
c~e o~ th~ ~n~l~ct~on moul~lns m~tho~, ~t ~ould ~l~o not b- moul~d
: - 57 - ~ .
_ ........
,-. ,.................... .- :
2 v l ~ ~
becau6e of a dif~lculty to ln~ct a molten mlxture o~ the m~n~tic powde-
and the resin ln e cavlty.
o~ the other hahd, ln c~6e of ~h~ extruclon mouldln~ methoa, ~ t~
thlckne~ magnet can be ~oulded ~-cause lt i~ ~oulded b~ contlnuou~l~
S flowins a ~olten ~ixture of ~h~ ma~netlc powder ~nd th- rQcin an~ by
sradually conv~r~lng thQ molten ~lxture. Accordln~ it 1~ clear that ~he
extru~ion mouldln~ mothod 1~ an Q~ectlve ~etho~ to mould a thi.
thlc~ne-s magnet h~vlng the thleknoc~ o~ lm~ or le~.
Example 14
Next effect~ on mouldlng radlai ma~net wlth a thin thlckne6s bY changi~
the ~a~netic powdor6 ~re ~hown in Table 13.
: ~he masnet ~ was a rln~ shaped ~a~net o~ the outGr dlam~ter 32.~mm,
thQ lnner dla~Qter 31.emm and the thlckne s 0.5m~, ~nd lt was moulded by
an extrusio~.
e compound w e~ comprlc~d 60 vol % OL ~ m~n-tic powder ~nd 40 ~ol $~. o~
recln ~nd nylon 12 wa~ w -d ~o~ the r~ln.
F~rthor ~- ~or thR magn0tl~ ~ow~ ~, a ~ro ~th m~gnet havlnu a
co~poc~tton o~ Co 0.672 Cu 0.0~ F~ 0.22 ~r 0.02~ 8.35 ~a~ usod, ~t
w~a ~d~u-t~d to m~kQ th~r~ge ~tlcla o~z~ r or ~ch t~t of ~Q~t 20
- 24 ~nt ~or ~o~p~r~t~xampl-~ ~a~ 25 - 27, an~ the ro~ult~ ar~ ~hown
~n Table ~3.
- 5~ -
- ~ -
,
. , .
- - ~ 2 ~
A~ 6how~ ln Ta~le 13, there w~- a cho.n~e of th~ maqn-t performance o~ the
magnet moulded by chan~ing S~ av~ra~ part~ cle ~ zo r of th~ ma5,met' c
pow~er. ~y maklng th~ av~ra~e p~r'clcle 8iZ~ r of the m~gnetlc po~der
~mal 1, the m~gneS p~or~nce of the magn~t 1- lmpro~red .
5 An~ a ~u~f iC~ ent ~a~net p~rfo~mAnce w~c o~tcinQd whoen th~ ~vera~e
partlcle ~ze r W~8 n~t more th~n 1/10 o~ the t~ cl~.ne66 o~ the magnet
moulded a~ticle.
However ln c~se when the ~ve~a~e p~rtlcle ~lze 1~ not leBs than ' /10 o~
the thickne66 of the m~gnet, the ma~net per~orm~nce 1~ low.
~e6t No ~r ~ (BH) max
L.~ rxG
~.8a 7, 5
21 20 5 . 95 7 . 8
~5 22 lo 6 . 18 ~ . 1
23 1 6.33 a.5
- 24 0.1 6.16 ~.0
. 70 5.60 6.5
26 100 -~.01 5.2
~7 150 4.70 4.5
~he re~-on why th~ ~bo~/~ r~cultc ~ obtaln~d w~, ln ca~ o the
axtru~lon moul~ , the ~n~tl~ ~ow~r ln the ~olt~n ~lxtur~ of th~
;: - 59 _
' ~ ,
. -, ,
" , . . . ..
:: i - : ,
~: ~: : : ::
-
2 f~ ~ ~! f ; ~
~, '..., . ~
The rea~on why the ~o~e re~ult# we~e o~talned wac, in Ch~Q of th~
extru~ion mo-lldln~, the masn~ic powd~r ln thR molt~n mixture of th¢
m~çnetic powder ~d the re~in wa~ orl~ntat~d ~t a ~oction ln whacl~ a
magnetic ~ield w ~ ch~r~ed by ~ac~lng throuch the ps~G~e of a die, ~nd
5 the moulded article wa6 extludQd out~i~e thQ tl~ ~t~r ~oli~l~yi~lç i.t
with coolln~ ln the dle by ko~pin~ thet ~t~ta a~ lt i~. Accordin~lY th~
ololterl mixture recelved ~ ~r~ ctlor, forc~ at the cont~ct ~ection With the
dle . Thus the orlenta~lon o~ Sho m~lgn~tic pow~e~ at th~ cor~tact ~urf a~
of the molten mlxture wi'ch the dl~ might be ~i60rd~rod. by 'che frict:lon
L0 ~or~e whlle it wa~ being ~olid~1ed wi~h coolinc even thouçh the ma~t ~3tlc
powder wa6 once or$entated in the die.
When a thin plate ~tate maqnet i3 moul~ed, the ~f ec~ o~ he layer w~lere
the sald orientatlon ~9 d~i~order~t become~ cign.ificar~ he thickne~ of
the layer i~ related with the p~t~ cle ~lze o~ th~ m~gnetlc ~0-4del: ac
15 well, and a~ the s~e~ult~ the aver~Q ~artlcle clze glve~ an lnfluoltce 'co
th~ ma~net per~orn ~nc~ o~ the m~gnet.
A~ lt i~ clear ~rom ~a:ble 13, in o~der to r~ducQ the ln~lu~nce, it i0
app~o~ri~tc thst the av~rage particle ~lze :~ of th- magnetlc powdee i0
1/10 or le~ of the thlcl~ne~G of the m ~netlc moul~ed ~rtlcle.
~' ' .
20 Example 15
Arl alloy havlng a compo~ltlon of Nd 14 Fe 81 B ~ w~e alolten in a
cruclble, lt wao cool~ap~ly by a m-ltLpan method and a th~n piece w~
prepar~t .
- 6Q -
. .
2 ~ J ~
~he thin pleca wa~ cru~h~ tlll lt h~ .n ~verage partlcl~ ~ize of 35~m,
~nd ocreat~ent~ 'IOWll in Table 14 were proc~ d ther-~ftQr.
TreatmQnt 1 Co~alt-~ho~phorw ~ chromium platln~
Treatment 2 SiO2 coating
Treatmen~ 1 wa~ that a~tar crushing the magneti~ powd~, a
cobalt-pho~phorus platln~ Wa~ carrlGd OUt in a ~odlum hypopho~pllitQ
reduced ~monla, alkallnQ cob~lt pla~lng bAth, th~n ~ chromat~ treatment
w~ performed. by putting the m~n6t~C pow4~r in ~ pota~ium ~lchromat~
bolutlon and a cobalt plating lay-r W8~ ~ormed on the ma~netic powde~:.
'rreatment 2 waE that pure w~tor a~u~ted lt~E ~H wit.h hy~rochlorlc ~cld
was m1xed wlth tQt~amethoxy6ll6ne to ma~c an Bp~roximate molar ratio of
4:1, and. a hy~roly~l~ wa~ carri~ OUt by ~tdin~ ethanol to it. A~t~.~r the
decompo~itlon an~ an hddition o~ ~ oUr~actant, the magn~tlc powd~r W~
, ~ddQd and W~!L6 ~tir~d ~or ~ ~r~termlned tim~.
`, .
: Then the maqnetlc pow~qr wa~ ~p~r~t~d fro~ thR colution, wa~ dryed and a
he~t tre~tmQnt W~6 p~r~orm~d to ~orm S$02 flim on the ~agnsti~ p~wder.
After the ~urface tr~tm~nt, 'ch~ gnetlc ~ow~er an~ the resin to m~k
re~tlo of 60 vol 1~ an~ 40 vol ~ wore w-lchad an~ war~ m~ce~, and aftl~r the
,
- 6 1 -
: ~ .
'' .
.. : .......... , . ,.............. . . . :,
. i : : , ,
2 F? ~ FJ ~
mixing, ie wa6 ch~rg~d ln a knQI!~dln5~ m2chine ~o knea~ tt ~d a ~ompound
wa~ prepared.
The kn~ading ma~hi~e h~rewlth w~d wal~ a roll~r mlll. Furt~e- a~ for th~
rQ~n u~d, 2 kind~ o~ re~in W~rQ ~oed. one wac ~e~ln a ~hich wac
copolymer malnly compri~in~ th~!~mo~ett~ ng tyS~o ~oxy ~ in, and the
othe~ ~sin ~ wa~ o thermopla~ic pol3~amida res~n (n~tlon 12).
P.fter cru~hls~g the compoun~ ~roduce~ a~ mo~ by an in~ec~lon
moul~ing machln~ or arl extruclon ~ouldin~ machine. In ca~e th~t ~esin a
wa6 u6ed, the moulded art~cl~ wa~ he-~Q~ to cure the re~in ~ftel: h~
moul dlng .
Fi~tly ln order to check in whlch 6t~p the ~llm tend~d to ~e removed, a
co-~erage rate was ~et~.rmined by taklnq a ~mple ~eor~ ~nd after each
~ep i n the total proce66~
The ma~sietlc ~ow~ u~d h-re wa~ a pl~tlrl6-treatQd on- ~rith the plat~nc
~5 thlcl~ne~6 of l~m, and. the moul lng wa~ car~iod out ~y sn extru~ion
mouldin~ machlne. ~hs result~ rQ shown in ~le ~5.
~e result~ ~er~ the ~ame ~or either ca6e~ of Reeis~ a and ~. ~rom Table
15, lt ic cl~ar that the f~lm cov~r~ge rate cud~enly ~rappe~ betw~en
be~ore and aft~r th~ knea~ln~. ~n othor ~t~p~, the drop o~ the cov~ra~a
rstlo ~ 6mal~ lt w~ ooneidQr~d that ~t ~ao du~ to a protection oE
th~ ~oated flln~ bY thQ mix~ r~ln ~psclally ~ter the kn~a~ing.
~ 62 -
. .
,: ,, :
, : - . - .,
.
3,~
a~lJ2 15
~te~ C9~ 95~
~efore mlxing 100
~fter mixlng ~8efore knoadln~) 95
After kn~adin~ tsefore ~uching)5iO
Aft-r cLucihin~ (sefor~ mouldlnu) 48
After ~oulding 46
On the other hand, be~ore kneading, the ~iolld rGc1~ and m~gnetic powder
~re merely mlxed, th~ re~iin do-c not glve the proteetlon for the ~oated
~ilm, i~nd tharefore the coat-d ~lm i~ mOVQd by ~ tron~ ~t1eeiEi to the
: 10 ma~etic pow~er ap~lied du~lng ~he knei~dirlg.
.
Accordln~ly the ~lxtu~e of tho magn-tic powder and the reeiin w~ heated
~efore the kneadln~, and the.n tho kn~adlng wa~i carrled out. The cov~r~
rate~ fter the kn~Ai~ing whlch w~s carr~ e~ out a~!t~r heatirl~ at variou~i
~emp~r~t~lre6 were 6hown ~n 'rable 16.
~5 'rhe tn~netlc powderi herewlth w ed were th~ ~latln~-tr~atea of the
plcting t~l~¢~nE~ s of lum ~or ~ t 2~ 3, an~ Te~t 34 thereafter wer~
S102 coated.
' '' ' '
.
R~ln a of th~rmo~ettln~ r~ln wa~ uc~d for the ~o~in. The cov~rag~
rate aft~r the knea~in~ W~B calculat~ a~ttin~ th~ cover~e rate ~efore
th- kno~ding ~att~r ~ixln~ 100, and ~h~ ~t~co~ity wa~ a vi~co~ity at
. .
:'`,
. - 53
''~
.
,
2~ 7~
a ~h~ar rat~ 100~ ~cl wh~n the mlxtur~ wa~ h~tod ~t ShQ temperatur~
indi.c~tQd .
T~mpe~tur~ Vi~coslty Covera~e Rate
~ ~ ol~
T~st 2B Room ~emp~rature - 50
2~ 50 500 50
300 74
31 85 180 90
32 lO0 7~ 94
33 120 - 10 98
; 34 50 Soo 60
. . .
300 85
36 85 190 53
1S 37 lOo 70 ~8
3~ 120 10 9B
Fro~ Table 16, the mixtura may have th~ v~ccoclty by ho~ing 1t. ~t i~
clear that the coYerage rat~ l~ lmprovQd wh~n the kn~a~in~ 1 ~ perorm~d
aftRr heatillg thQ mixturs to m~k- lt in ~ st~te in whlch it h~s the
, ~0 vi~coc~ ty. Althouqh the cover-~ ratQ o~ the p~a~e one becomes wors~a
than lt o~ the 5io2 coat~d on~ wh~n comparsd in tha ~m~ condition
b~c~u~e of lt- w~ak adhe~lon o~ th~ ~llm, ~n ~m~rovement i~ ~Qen when tha
.
. .
-- 64 --
.. ; . ,
.....
, ~, .
.
?. ~ r ~'
viscos1 ty reache~ 300 kpoise, and below it, the coated film was
cuf f lcien'cly protected .
It is con~de~ed that the ~bove re~ult6 ~re o~ta~na~ ~oecau~e as to the
removal o~ ~he fllln ~u~ing 'eh~ knakd~n~ lar51~ly $nfluenced by a
5 6treS5 0~ the rolle~ when it i~ ~pplled to a CtatQ in which a ~ufficisnt
: heating i6 no~ ~lven whQn the ~lxture ic char~od i~ th~ kneadin~ ma~!h~ne,
: and the lnfluenc~ i~ relieve~ by glvlng the vi~co~lty to the m~xture.
.
Next an ox~dation re~i6tance o~ a ma~n~t ~roduc~d by the prod.l~c~lor-
proces6 of thls inventlon was inve~t1gated. ~he re~ult~ of ~est 39 and
40 a~ thl~ ~xample~ and Tegt 41 and 42 a~ comp~ratlve example~ are ~how~
in Table 17.
Surface ~reatment OxldatlQ~_Resistan~
Te~t 3~ - TrQatment 1 A
" 2 A
. -- ----~ _ _-- _ _ _ .. _ _ _ ~.. _ _ _ _ _ _ _ . .... _ .. _
4 1 " 1 C
. 4 2 " 2 E
,................................ .
A ~ Excell-nt
B - Goo~
C - ~d
,
- 6S --
: : :
;
:~ . , . ' ' ~ ' ':,: '
: '
2 ~
Te6t 41 ~r~d 42 of the comparat~ve xample6 were the ca~a~ ln which tlle
kneadlng was carrled out without heatln~ ~ofor- th- kneadis~, an~ t 39
and 40 of ~xatnle6 wer~ c~rrled out ~y h~atln~ at 100 k~ol~e.
~he oxldatlon re~l~tAnce wQ.~ a re~ul~ hfter ~torln~ th~ le in a
con~tar~t temperature and const~nt hum~ dlty ovQn t 80C x 95% ~or 100
ho~r~.
~t 1~ eleal that th~ oxidatlon re~l~tance i~ improved by the hoat
treatment be~ore th~ k~0~din~.
.
Ex~mple 16
i ', , .
~aw material~ to make a compc~tion of sm (Co 0.672 Cu O.OB Fe 0.2~ zr
0.02~) ~.35 were moltQn, were ca6t~d, ~n lngot produced waR m~netic~
cur-d by a heat tre~tm~ns, an~ then a msgnQ~ic powdQr havlng ~n ave~ açJe
par'clcle ~lze of ~O~lm wae o~tained by cruohing it.
r, 'rhe pow~er was mi~ced wlth nylon 12 pow~er and zinC ~t2arate powder to
m~ke a ratlo of 92 wt~, ~.B wt~ ~nd 0.1 wt%, re~p~ctively.
~he mixtur~ w~ then kneaded by ~ two axe~ e~ctru~ion knead,ing ma~hine at
260c. rhe kne~d~d mixture wa~ ~rallul~ted to particlas o ~che -o-lt~r
di~m-ter of 1 - lOmm to m~ke ~ raw material com~ound, an~ ~ cylin8rlcal
- ma5n~S wa~ mould~d. by as~ extmglon ~oul~lir,u ~achina.
l~he mouldlng me'chod i5 ~xplained in ~cco~anc- wlth ~l~ure 10.
- 66 -
:
'
~:;
,, .
... : . - ~ . ::
. . . .. . .
: , . . .
.. .
, . ' . ' : ',: ~ . ,
Ac shown ln Figure lC, the extrU8~n mould~n~ mBchin~ i6 con~t1~ut~d by a
hopper 101 which 1~ a ~oction of ch~rging m~terial, ~ cylin~r 102, a
~crew 103, an a~aptor pl~te 104 to ln~tall a ~la to thQ cyllnd~r sectlon
102, a die 105 and a Orl~rlnu motor for the ~cræ~ (~hlch i~ not ~hows~ ln
5 Figure ) .
~ .
~rhe aforemQntior~d ~s-an-llated raw mat~r~.al compoun~l 111 wa~ char~ed in
the extruslon moulding machlne. $h~ raw Ir,atgrlal compound 111 w~ hea~.ed
in the cylind2r 102 ~t 250C to m~lk- it ln ~ ~uidlze~d 6~ato, and i~ w~s
pa~6~d thro~l~h the dle 105. -
10 In thi~ ~xample, the ~ie tempera'cur~ at the mouldins W~ 250C, an~ t;hecoolln~ wa6 ~rrle~ out ~y a .forced ~ir coollnç at the ou'cl~t se~ti Oll of
~he ~lQ. ~he cize o~ th~ moul~d ~rtlcle producQ~ w~ the o~lter dizmeter
of 33mm alld the inner di.alneter 4~ 32mm.
The moulded ~rticle was made ln thln plat~ c'cat~ ~y ~ unit chown in
,:. 15 Elyw.~e 11.
Fl~ur- 11 was a drawin~ ew~d from Up~ , 'ch~ cylindrical m-~ul~ed
~rtlcle 112 oxtrude~ from the ~ie 105 wa~ ~plit lnto two e~al ~ tion~
of thQ upl3idQ and th~ d.ownoid9 3~y ~h~ eutter 501~ in~tall~d in front o~
the dle 105, an~ the bl~ect~ oul~d articl~ wor~ ~lould~d into thln
plate 5tate maonot by pa~inç ~etwe~n 2 s~tc o 2 rollor~ 502 po~iei~ned
in the re~l~war~ o~ th~ cuttQr S01.
;
, ; .
-- 67
,:
- . . . . .
.:
2 ~ ril r-
Then the end surfac~ of the thln pl~t~ c~te ~n~t 503 w~e cut to m~ke
lt ln a ~ re~ ~lz~. ~he ~iz~ of the moul~-d artlcle wa~ tho wld~h of
50mm and th~ thlckne~* of lmm. The magnetlc prop6rty of th~ moulded
artlcle obtaln~d 1~ ~hown ln Table 18.
5 A~ a compar~tl~e examp3.e, a thln plllte ~t~e mould~d artlcle wa~ mc~lllded
by ar, xtru~lon ~y u2lng ~ dl~ which w~ n~r~lly w~d fo~ an extrusion
moulding of ~ thln pla~e ~tllte pla~lc, and lt6 maqn~ic property 1
~hown a~ T~t 44.
A~ ~or the raw m~terial compound, the g~m~ ma~netic powder, ny~c.n 12
powder and zlnc ~t~arat~ powde~ a~ To~t 43 of ~xampl- w~re mlxed to mak~
ratlo o Sl.5 wt~, 8.3 wt~ and 0.~ wt~ re~pectlvely, they ~ere knead.~
~ere gr&nuIate~ nd wera m~ulded for the d,~termlnation of the m~n~tlc
prop6rty. l'he ~iæ~ of the moulded ~rtlcle was th- c~me a~ Te~t 43.
15 In T~bla 1~, a moul~.abillty o~ ~xample of thic ~ nventlon ~T~t; 4~ ) arld
the compa~atlve example (To~t 44 ~ 1~ alco 8hown wlth the ma~notlc
property .
.",
,','~ ~.
('dX~ m~c
~Q21 I~I~L~
T~t 43 (~a~pl~) 2.5 G
.
~e~t 44 ~comp~r~tive
. example~ ~, 4
- 68 -
.,~
:
2 ~ ~ ~~ L' b 3
G . Good
O ~ Ordin~ry
As it i~ cle~r from Table 18, th~re i~ no ~l~nif 1 c~nt ~fer~nce on the
ma~netic property b~we~n T~c'~ ~3 o~ ~x~plQ and ~e~t 44 of tho
5 co~parativ~ example, And a m~gno~, havlng it~ ms~n~t perfor~ance e~u;~l to
or ~bovQ tho~e obtalnod by tho conv~ntlona~ moul~lng method, car~ ~e
moul ~ed .
on th~ othox hand, ~ro~n a vio~polnt o~ th~ moulda~lllty, it W~8 dl~flcult
to achleve a ~table mouldlng ~or Te~t 44 of thQ ~ompa~tive example, and
lO a rate of an t~ei~cte~ ~rtic.le wa~ hlgh . Furthermore th- f abricat~ on ~ost. of the die :uced ln T~t 44 of the co~a~Aratl~e ex~mple we~ appL~oxl~ateïy 3
tlmes hlgh~r- than th~ dle o~ ~e~t 43 of ~xample, and lt was mt)re
exp~n~ive than a total co~t of th~ 4ie an~ thc pre~c unlt of Exa~plo.
~ccordlrlsly, a hi~h per~orm~nce thin plat~ ~tat- re~ln ~oun~ type rar~
15 e~rth magnet can bo p~ oduc~d with a hl~h pro~u~tlvlty by u6ln~ t:h~
mouldln~ mQtho~ of thi6 tll-rentlon.
Example 1 7
,
Raw M~toLlalc to mak~ a com~ocltlon of N~ 14 5ro 0.95 Co 0.05) eo.s ~ ~.5
.wero molton, wor~ cA~ted and, a ~uenched rlb~on ~a~ prep~rQd ln an ~:rgon
20 atmo~ph~re l~y ucin~ a Quew~in~ ~nd rl~bon rolllng m~6hlnQ from the ln~ot
.
o~talned. : _
: .
.
. . ' '~
. . .
2 ;J _. .. v ~
~he ~uenched rlbbon wac cru~hed and ~ magnatic pow~er o~ An av~L ~ge
partlcle ~ize o~ 20~m wa~ obtained.
Thls m~qnetlc powd-r wa~ mlx~d wlth 4 ~e~ln powd~r co~p~l~ln6 b$~Phenol A
type ~poxy, novolaX type ~poxy and vl~ylbutyral-vinylalcohol ¢opolym~r,
calcium stearate po~der ~nd ~ a powd~r a~ a~ltlve~ ~o mh~o a ratio of
90.3 wt~, 9.1 wt~, 0.4 wt~ and 0.2 ~t% ro~pectlvely.
The mlxt~lre wa~ kn~adad by a 2 rollor type m~ll at gO~. The kn~aded
mixturo was ~anulated to outer ~l~met-r o~ l - lOmm partlclQ~ to m~ke a
r~w materlal co~po~nd ~nd wa~ moul~ed In a cyllndr~eAl ~gnet by uGinQ
the extru~lon mould~nq machine ~hown in Flgur~ 10 of the ~orementioned
Example 15.
Af~er the moulded articlo was cut lnto ~n appropriate len~th, one ~int
on the circumferenco o~ the moulded artlclo w~ al~o cut ln paral~l w~.th
itE central ax~s.
~he moulded art$cle wa~ ~ired at 200C for 45 ~illUt~ whlle it wa~ b~lng
pr~6~ed to mSke a thln plate ~tatQ by a pre~ unit ~hown in Fl.~ure 12.
: ThQ pre~ unit ~hown in Fi~ure 12 i~ to ~r~ a mould-~ art~cle ~y movlng
t~e ~r~-~ plate 601 loc~tsd ~n upp~r po~ltion ~ownwa~d ~ ~hown by ~n
arrow. ~he thlckn~ o~ thQ mould-d artlcle 603 i6 ad~u~t~ b~ a Bpacer
602.
-- 70 --
....... . . .
~ r 1 ~
;3
The pre6~ unlt ~4a~ placed in ~ firln~ furnace, ~ras heat~d ~nd thQ
afor~mentioned mould~d artl~le w~ ~et on the pre~ plat~ 601~
A pre6c w~ carrled out to m~k~ 2 thin ~late statQ wh~n the v1 sco~ y of
the moulded ~rticl0 dropp~d, and lt ~a~ ~urtl~er h-~tQ~ to cro~slink the
organic re~ln ln the rnoulde~ artlcl~.
La~tly the dces o~ the mould~d nrtlol* w~r~ cut and a tl~ln pl~t~ ~ta~Q
rna~net with the des~red cl2e wa~ proparod. rhe m~gnetlc property and thQ
sl~race condltion of th~ thln plats ~ta~e moul~d ~rtlcl~ of T~t 4~ -
S3, in whlch the sixe6 of the mould~d. article ~xtr~t~d b~r ~n extr-~lon
10 were altered, were 6h~wn in Table 19.
e 1 9
outer D1am~ter In~Qr D~Ams~er (BH) max Surf~c~,
~re~t NQ (~m~ M~e ~ SQ~Q~
49 22 22 0 . 91 5 . O ~ood
; 15 50 22 1~ O. ~24 . 9Good
51 22 16 0 . 73 - ~ad
52 33 25 0 . 76 4 . ~ Good
53 33 23 0.70 ~ d
In ~able lS, the llaad~ mark in the E-lrf~c~ conaltion m~ans that lt i~ not
; 20 u~a~le a~ a ma~nat becsuse of a ~orm~tlon o~ c~cks 02 the sur~ace.
,.
':
~ '
- , . . .
.
- , . .
,~ . - . .
2 r~
~ . ;j
AS ~ t 16 cle~r ~rorn Toble 19, i~ thQ ratlo d~D betw~n thc outer di~m~er
(D) and the lnner ~l~m~t~r ~d) ~ b~low 0.7g, lt can not ba ~t~ed a~ ~
magnet. ~t 1~ con~dered that thi~ i~ du- to a formatlon o crack~ on
the surface by a ~tre~6 ~hQn lt i~ ~crQated to m~ke a ~hir, pla~e 6tate
5 6ince the thickne~ of the cylin~ric~l moul~ed ~rticle lo thick relatlve
to the outer dlama~er~
Conc~rning th~ m~gn~t~ c prop~r~y, th~r~ 15 no problem lf d/D 1~ 0 . 7 5 or
more.
Accordin~ly ln the mouldl~u metho~ of thl~ ln~J~ntlOn when d/~ i6 limited
lo a6
O . 7 5 ~ < 1,
a m~gnet having a high ~agnetl~ ~roperty w$thout ~efect~ ~uch a~ the
crack, etc c~n be produced.
~xampl e 1 e
Raw materlal~ to make a compo~l~lon o~ 8m (Co D, 672 Cu 0 . 0~ Fe 0 . 22 Zr
0.028) e.35 were m~lt:en, were ca~ted, ~n ingot pL~odNc:~d wa~ ma~naticEIlly
cur~d ~y a heat treatm~nt, and thQn a m~n2tlc pow~Qr havln~ the ovelag~
partlcle ~ze o~ lOllm wa~ prepared ~y cru~hlng the ingot.
Thl~ pow~eL^ w~s mlxed with nylon 12 pow~er and zl~c ~t~ar~a pewder to
ma~e 2 r~tio o~ 92 wt;%, 7.B wt% an~ 0.2 wt96 rerpe~tively.
-
-- 72 --
: ~, ' . :
2 ~ , r ~
Then the mlxture w~ knaad~d by a two ax~ ~x~ru~ion kneadl~g m chine at260OC. ~he k~Qa~d mlxture waY ~ranulatod to partlcle~ h~vin~ the 3u~r
dlameter o~ 1 - lOm~ to m~k~ a r~ matorl~l compound, ant a cyllndrlc 1
magnet w~c mouldQd ~y an ex~ru~ion moul~ing machlne ~hown ln Flgure 1.
The mouldlng msthod wa~ ~he ~am~ me~hot So ~x~ple 1.
As ~ame to Fl~ure 1, thQ ~xtru~lon mouldin~ m chine cOn~iCtB of a hopper
101 ie a r~w ~ae~rlal ch~r~ ctlon, a cylln~er 102, a ~crew 103, an
adaptor plate ~04 to equlp a ~le ~t th~ cyllnder, the die l~S and.
drlvin~ ~otor for thQ ~cr~ ~which 1~ not ahown ln ri~re)~ and further
lo ~n electromagnetlc coll 109 to charg~ a ma~netlc field ln t~e dle lOr, i~
pofiitioned ~t the out~ide o~ the di~ 105. 106, 107 ~d 108 are heate~.s. '!
.
The aforementlon~d ~r~nul~t~d raw mat~rial oompound 111 wa~ char~ed in
the ~xtrucion mouldlng machlnQ. Th~ raw material compound ~aE heat~d in
the c~llnder lOZ at ~.60c to m~e lt in a fluldiz~d ~tate, and wac E)~ed
through th~ die 105 o~ which structur- w~s ~hown i~ Fi~ure 2.
'''
1a 1E COn~t1tUtQ~ ~Y an OU~r ~ie 201 ~nd a mar~d~:e1 20~. ~he O-~te~
~ie i~ mate O~ a nOn-~ag~-S1C ~at~ria1, ~:iUt a r1n~ ~haPed olagn~tiC
materl~l 201~ ~ B in~tall~d at tho front 6n~ to in~uc~ a magn~tlc flux.
The m~ndr~l 202 ~6 ~l~o ma~e of a non-m gnstlc m3torlal, ~n~ ~t lt~ f.ront
en~ 4 magnatlc materi~l 202~ ~ ln~t~ a~ wRll,
- When a current iR turne~ on in the el~ct~om~gn~tic eoll ~09 ln~t~lled
out~ide th~ di~, the m~net~c f~ux ~en~r~t~ flow~ ~n ~ di~ction of the
; - 73 -
:
.; . - :
- :~' .:
'
arrow H in F~ure ~inc~ lt tends to ~a~r ln a ma~netlc materi~l ~lth a
high m~gnet~c p~rma~bllity. Th~refore ~ r~diated m~etlc 1eld 1
gener~ted. in a ~pace (hereinsfter ~alle~ ~ an orientatlon sectlon]
betwaan the front ~n~ 202a of th~ me~dr~l an~ msgn~ti~ ~t~ri~l ring ~Ola
in~talled ln the out~r dle. ~hu~ while a m~ne lc com~o~ltlon p~se~
- throuqh the orl~n~atlon ~ectlon, it ic moul~d with ~ progreeoe of an
orientatlon o~ the maonetic ~owder.
In thiE ~xample, the m~netlc 21~1~ o~ th~ moul~lng wa~ lS kOe, the die
temper~ture at th~ moul~ing waG Z50c, and tha coolin~ carried out by
a forced alr ~oollng at the outlet section o the die, Thu~ the
orlentated ~aw m~terial compound 111 wa6 ~oulded by an gxtL~U~ion by a
~olld~flcatlon wlth ~oolln~ at the outlo~ o~ the ~ie. ~he slze of th~
cylindrieal moulded arti.ele wa~ the out~r diameter of 33mm and the ilme~
diamoter of 32mm.
~he moulde~ a~ticle wn~ cut lnto ~ ~ultable l~ngth, wa~ demagn~tized, and
further lt wa~ devidad lnto two cqual ~ctlon~ in parallel with th~
~entral ~xi~ of the moul~ed ~rt~cl-. The moul~e~ article wa~ ther made
ln a th.t~ plate ~tatc by h~atlng ~t 180C wlth a pre~ unlt aho~l in
Flgur~ 12.
.
The pres6 unit 1~ to pra95 a moulded art~cle 603 by mo~inU the p~6
pla~e 601 lochte~ ln upp-r po~itlon downwArd a~ 8~0wn by an ~rrow~ ~he
~hickne~ o~ th~ moulded a~tlcl~ lc ~d~u~t~ ~y ~ ~ac-r 60Z. ~h~ plo~5
unit wa~ pl~c~d ln a flrlng ~urn~eo a~ oum~ ~ff Ex~ple ~7, ~a8 hoated an~
the moul~d artlcle w~ ~et on ~h~ pr-~6 plate.
:
- 74 -
.:
.-:
. :' ' ~ ' ' , ' :
. ,. ' , , ,
~ ~ ~ r ~ ~ r . ~
A pre66 wa~ carrl-d out tO mak~ a thln ~late ~t~te whQn the v1sco~i~y of
th~ moulded article dropped, th- ed~Q~ wera sut, and ~inallY a th1n pl~te
ctat~ magnet with th~ de61rad alz~ w~ o~taln~d. Tha slze o~ ~he mould~d
artlcle wa~ the wldth o~ 50mm ~nd thQ thlckn~ of lm~. The ~onQtlc
propeL-ty of the moulded article obtalned ~n ~ 4 i~ ~ho~ ln T~b~r? ~n.
A~ a comparative example, ~est 5~ wa~ carrl-d out by an ~xtruclon
mouldin~ by ucing a dle shown ln rl~uro 6, and ths magn-tlc pro~er~y of
th- ~ould~d art~cle in a thin plst~ ~tate i~ ~lso ~hown.
.
A6 for th~ rsw matQrial co~poun~, tho came one to Test ~4 wa~ u~ed.
In the die, wh~n a cUl^r~nt i~ turned on ln ~he electrom~gnetlc coll 403,
: a;~agnotic ~ield ~er~ical to the pa~a~e of the co~pound ln ~1e di~
~ormed between uppel an~ lower ~ole piece~ 404. Th~rQfore a thl~ ~late
8tate ma~net o~ whlch th~ ma~n~tic powd-r i~ ori~ntat~d ln thQ thickn~oc
dir~ction can b~ m~ulaed. ~he ma~tlc ~lel~ ~t the moul~ln~ wa~ ll koO,
. ~ and the cize of the moulded ~rticle wa0 the ~me to rx~mple o~ Te~t ~4.
.
A mould~bllltY i~ al~o ~hown ln Tab1Q 20 with the ~acnetlc property.
~'
. ~B~ max
.,
're~t 54 t Example ) 7 . S aOod
~e~t 55 t Compar~tlve
- 7S -
~'' .
.
.. . .
'
~ r~
example ) 2, 4 Ordlnary
A~ it i ~ cl~ar from ~ e 20, though ~ch~ ~amQ mouldlng r~w materi 1 was
u~ed, the comparati~e ~xamplo ~re~t 55 ~howe~ lower magnetlc ~roperty. It
wa~ ~oncldered that ~ t wa~ ~ue to cn lm~o0~ itY to enlar~ the
s ~a~netlc i~1d o~ the moul~ing becau~ of th~ ctructu~al p~oblom of tho
dlo ~n ca~e o the comparat.$v~ xamplQ ~e~t 55 r~cLIlting arl in~ufflolent
or~entatlorl of ~he ~ag21otlc powder.
Furthermore it wa~ ver~ dl~f~cult tG achle~e ~ ~tabl~ mouldlr,g in ca~;e of
Test 55 o~ the con)p~ratlve example, ~nd it had a hlsh re~ection rat~.
10 Mo~eov-r the fal:rlcatlon co~t of the di e w~d ln the com~arative xhmplQ
're6t 55 wa~; app~oximately 3 tlmec more eXPen~ive than the diQ . u~ed ln
Te~t 54 of Example, and it wa~ more co~ty 'chan the tot~l co~t of the Ale
and th4 pre~ unlt ln ~xamPle of T~st 54,
,
: l COn~Qquentl~r, by using the mou~dl~g mQthod o thl~ lm~ellt1 or~, A h~gh
15 pQrfor~ance thln plato ~tate ~:e~in i~ound type rarQ ~rth ma~nQt c~n b
produced wlth a ~ood prod~lctl~Jity.
Exa~le 19
Raw matsrial~ to m~ke a comp~-ltlon of SQ~ 13 FQ 82.7 9 4.3 w-r~ molt~rl as
~i~ilar to Example 17, wero ea~ted an8 a ~ucnched rl~bon wa~ pr~pa~-ad ln
20 an ~rgon ~t~o~har~ by u~in~ a ~usnchlng and rlbbon rolllr~g machine rom
the in~ot obtain~d.
-- 7 6
:
,~ .
.
.
:
.. . .
:.- , ~ - ,
, . . ~ , .
- - - 2 ~
The quenched rlbbon wa~ coaro~ly ~ru~h~d, it wa~ tran~ered to ~ mould,
and a high pr-~Eure pra~ mouldln~ wa6 carrl-d out ln ~n arqon atmo~phQr~
at 700 - 800OC wlth a 20 ~mmZ pr~uro ~or a ~hort tlme.
' :
The con~olldated artlcle obt~ined h~d a ~en~lty ~lmo~t loO~ he
co~solldat~d artlclo obt~nod wa6 mou~ed ag~in ~y th~ hl~h temPerat~lre
pres~ mouldln~ ln a vert~.cal dlrectlon to tho flr~t pro~ln~ dlre~ion in
an ar~on at~o6pherç at 700 - aoooC wltll a 10 Kg/m~2 pros~ure (Namely
die Up~Qt wa~ carr~ed out).
:,
The. bUlk ~tate ma~net w~6 cru~he~ and a ma~net~c powder of an average
partlclQ ~ize of 20~m was obt~ln~d.
,
The magnet~c powder w~ mlxed wlth ~ XQ~ln po~der comprl~ln~ a m~xtu~e of
bl~ph-nol A tYpe epoxy, novola~ type epoxy and vinylbutyral-vlnylalcoho~
~;. copolymer, calclum ~tearate powder and ~llloa powd~r a~ adtitlves to make
.~ a ratlo o~ 90.3 wt~, ~.1 wt% and 0.~ wt% and 0.2 wt~ r~6pectivel~.
,
~:~ 15 Then the mixture was kn~ded by a 2 roller type mlll ~t 9oC~ ~he
:
kne~dod mixture WaE ~r~nulated to particlo~ of the out~r dl4~ter o~ 1 -
....
lOmm to make a r~w mat~rial compoun~, und B cyllndric~ net wa6
mould~ bY u~lng ~n extru~ion mouldlng maehlnQ ~hown ln Flgure 1 and a
.~ Ci- chown ln Flcure 2 a~ ~mllar to ~x~mple 18.
', ',.'~
~........................................................ .
he ~oulded ~rticle wac cut $nto a ~ultable l-ngth, wer~ de~agneti7.0d,
~ ~nd further one point on th~ cire~mferencQ p~rallel ~o th~ centr~l dXi~
1~ of th~ moulded artlcle w~o cut. ~hQ moulded ~rtlcl~ w~o flred at 200C
.;
~ - 77 -
:.
: ' ,
2 ~
for 4S mlnutes whlle it was belng m~de 11~ a thln Plate Btate by a p~ s
unit ~lmllar to SxQmple l~ to cro~llink thæ s:rs7anlc r~sln ln the mouitied
articl~ .
~h~ ma~n~tic ~rop~l~ti~H o~ the thin plat~ ~t~tQ moulded ~rtlcle~ when
5 Ta~t 56 - 61 were ca~ri~. out bY chano~n~;~ the si2e o~ the mould~d.
articles of the extru~ion mo~lldlng are ~hown ln T~ble 21,
~a~L ,
Ou'cer Diameter Inner Dlarneter ~H) m~x
Te~t N~ .~mm.l. ~ mm ~ MGae ~
56 22 20 0 . gl10 . 2
57 22 19 0, 56 10, 0
58 22 lB o . B2 8 . 2
59 3~ 32 o . 97lo . 4
~o 33 28 o . ~ lo . 1
61 33 25 o . 7~ 7 . s
A~ lt i~ clear from ~able 21, if the ratlo ~/D bQt,W~n the outer diam~ter
tD) and thQ llmer dlameter ~ bolow o.B5, tlle m~snatlc property i~
~et~rlor~t-d. It i~ ~on~ldere~ ~hat thle 15 duo to ~ fo~m~tion o~
~l-ord~ on tho ori~rlta~lon o~ th~ m~netlc powde~ while ~t i~ b~in~ made
20 in a thin ~late ~tate b~cau~e th~ thickn~c~ of thQ cylindrica~ mo~ld~
artlcls 1~ thi~k lsl ccnlp~ri~lorl wlth-'ch~ outer ~la~at~r. ~on~Qqu~ntly in
th~ ~oul~l~ng ~roc~s o~ thi- lnv-ntlon wh-n th- ~/D l~ llmlt~d a~
O.B5 c d/D ~ 1,
., '
'. '
2 ~
; - a ~agnet wlth a high ma~llet pe~formance c~n b~ produced.
.
-
,.. .
"
.
.; ., .
,
.~,, .
~,,
~, ' . . ..
~:;
.',,'',; .
;
.,
, .
" .
i.,.'.'l .
~' ''
~. . .
,~ , .
'' '
~ '"
,.
.. .
. .
s;, .
~. ~ 79 -
,~ .
. ,:
:
:., `
;. I .
