Note: Descriptions are shown in the official language in which they were submitted.
10~'~5~9
~¦ BI~CKGROUND OF TIIE INVI~I`ITION
.~
; ¦l This invention relates generally to f].exible seals
, and seal assemblies of the type employed in rolliny mills where
i roll necks are journalled for rotation in oil film bearings.
U. S. Patent No. 2,868,574 discloses one well known
example of a prior art seal and seal assembly which has been 'I
employed extensively and with considerable success in the rolling !
jj mill field. In this arrangement, a flexible seal i5 mounted on
I the tapered section of th~ roll neck for rotation therewith.
~ 10 ! The seal is surrounded by a stationary circular seal end plate
I ¦ having a radial].y inwardly extending rigid flange separating
oppositely arranged shoulders. The flexlble seal has radially
outwardly extending flexible flanges which are in sliding
contact with inclined shoulder surfaces on the seal end plate.
15~ ¦; The flange/shoulder surface interface on the bearing side serves
to ~reta.in bearing lubricant ln the bearing, and the flange/
shoulder~surface interface on the roll side serves to exclude
contamlnantsl~such~as~ cooling water, mi].l scale, etc. from
penetrating lnto~the bearing.
20~ ~ The'~above-described arrangement has been in largemeas~ure~e~f'fective~as evidenced by i.ts widespread commercial use. I I
S~ill, problems have been experienced with regard to leakage of
bearing ~ubricant~, ~ontamination o bearings and excessive wear
~ : , ,
~;~of~qeal components.~ IL has now been determined that these
'25~ ~ problems are~occasioned primarily by the design of the Elexible
~se~l ~langes,l~and the manner in which they slidingly engage the f
~surrounding shoulder~surfaces of the seal end plate. More
part'icularly', in;this~prlor ar~ construction, the flexible seal
~1anges~are~relativeLy thick and heavy~t.hroughout their entire
30~ ¦~Xadial;~len~th.;~When~the seal is i.nstalled, these flanges are
~ 2- ,
, ~,, .. . .: . - . ... - -
l~ ;
¦lbent or flared in opposite directions by the surrounding shoulder~
¦,of the seal end plate. This creates a heavy pressure at the flange/
~shoulder surface intex~ace which in turn can result in excessive
~Ifriction and heat being generated during operation of the mill.
~The excessive Eriction accelerates wear of both the flexible flanges
jand the shoulder surfaces of the seal end plate. The excessive
heat has an added adverse effect on the flexible flan es, causing !
.- ?l ~;b~Q
jlthe flange ends to harden and crack. When the fi~i~r~le flanges
1!become worn, hardened or cracked, the flexible seal must be replaced~
~ Likewisel when the shoulder surfaces on the seal end plate become ,
worn, they must either be reground or if this is no longer possible,
- I! the entire seal end plate must be replaced Such replacements and'
repairs are both time consuming and expensive. Moreover, any
leakage occuring prior to replacement or repair of seal components;
110an result in loss or contamination of bearing lubricant. The
foregoing problems, particularly those related to cracking and
hardening~of the flange ends, have gradually become more severe as
rolling speeds have increased.
It has;also been determined that the relatively thick
20; ~ hèavy~flanges~of ~he;prior art seal are not as flexible as they
shoul~ be,~and~th~at after being installed, they have a tendency
i ~to become;~perman ntly distorted (a condition referred to as
~"taking a~set"). This loss of resiliency can have a further
` ~adverse;efLect on sealinc3 integrity.
25~ The oppositely inclined shoulder surfaces on the seal
end~plate shou~1ders also present problems, particularly when
; ~the roll under.goes~axial shift1ng, a normal occurrence during
~`~ rolling operation. When this occur.s, the flexible seal flanges ¦
~will~'ride alony the~surrounding shoulder surfaces~, thus changing
30~ the~degree to which the~ flanges are deflected radially inwardly
~or outwardly. This~changes the pressure at the flange~shoulder
~;~,ur~ace~interface. At one extreme/ when a flexible flange
-3
3~
¦` un~eryoes maximum inward deflection, the pressure at khe flange/-l
shoulder surface interface is increased and this in turn increases
heat and fric-tion. At the opposite extreme, when the flexible
~I flange undergoes maximum outward deflection, the pressure at the
!i flange/shoulder surface interface is decreased, thus raising the ¦
possibility that sealing integrity may be lost, particularly when
~I the flexibl~ flange and/or the surrounding shoulder surface has
- '! already undergone some frictional wear.
! An object o~ the present invention is the provision of
I an improved flexible seal of the type generally described above
having a novel and improved design which either obviates or at
¦ least substantially minlmizes the aforementioned problems. In
` 1 the preferred embodiment to be hereinafter described in greater
i 1 detall, this is accomplished hy providing an angularly disposed , -
lS~ ¦ flexlble lip lntegrdlly ~oined to the outer edge of one or both
of the~flexible seal flangesO Each lip is preferably joined to
its~re~speative~flange by a means which accommodates resilient
flexure of~the~ lip. Each lip is preferably provided with a
gradual1y~diminishing thickness, with its minimum thickness
20~ ~I being at~the outer lip edge, and with its maximum thickness being
lessjthan~thickness o~ the seal flanye to which it is integrally ¦
oined. ~Wlth this arrangement, when the seal is mounted on the
roll neck within the confines of the seal end plate, each lip
~is~ lexed radially inwardly by the surrounding shoulder surface
~25~ ~on~the~seal end plate. ~Because the lips are capable of being
! ~ resilientIy~lexed in relation to their supporting flanges, and
~because the :Lips are relati~ely thin and tapered, and thus
~rel4tively more resilient than the ~langes, the resulting
; ~ pressure~;at the~lip/shoulder surface interface is rela-tively
~ ~ llgh~ as co-pared with the prior art Arrangement. By thus
4~
!
,, , ., , , , " ,,, , "
s~ l
i
i reducing the pressure at the lip/shoulder surface interface,
; ~ friction is reduced, thereby providing longer seal life with
improved sealing integrity.
I! The angular relationship of the lips to their respective
¦l~lanyes is also seen as a decided advantage because centrifugal
¦force will be employed more eff~ctively to urge the lips radially !
¦¦outwardly against the shoulder s,urfaces of the seal end plate. I
j This effect wlll increase or decrease in direct proportion to the
Irotational speed of the roll, thus providing peak pressure at highl
¦rolling speeds, when it is most needed, because at higher rolling ¦
: Ispeeds more oil is pumped through the bearing.
¦l Another objective of the present invention is the provision
!i of an improved seal assembly embodying a flexible seal as described
above in combination with a redesigned seal end plate having
lS~ shoulders~which have shoulder suxfaces parallel to the rotational
j axis of~the roll nec~. With this arrangeTnent, as the roll under-
oes;~axial~shifting, the seal lips will~not experience changes in
rad1al def1ectlon. Thus, the pressure~at the lip/shoulder surface;
interface will remain unaffected by axial roll shifting, and this
j~in~turnj~will promote longer seal life whi~e reducing wear of the
~s al~end plate;shoulders.
Another object of the present invention is the provision¦
;of a~Llex~ible seal which is better adapted for mounting on the
~tapered~seation of a roll neck. In this connection it has been
~noted~that with~the prior art seal arranyement, the seal flanyes
¦~are~equal~ln len~h when the seal is unmounted. However, the
stresse~and;resulting~distortions experienccd hy the seal body
; when~1t~is~mounted on the tapered section of the roll neck cause
~the~seal flanyes ~o assume di~ferent~radial lengths in the
mounted~aond1tion. ~This probIem has now been overcome with the
present~lnvention whereby preferably the seal ~langes are molded
with uneqyal lengths to compensate for any subsequent seal
! : ~ 5--
53~
li i
1I distortion during mounting. !.
¦l These, as well as other objects and advantages of the
,I present invention, will now be described in greater de-tail in
j~ connection with the accompanyin.g drawings, wherein:
~¦ Figure l is a cross-sectional view of a preferred
embodiment of a ~lexible seal in accordance with the present
Il invention;
jl Figure 2 is a cross-sectional view of a preferred
embodiment of a seal assembly in accordance with the present
invention, the said embodiment being specially adapted for "wet"
. applications where liquid coolant is being applied to the roll
~! surfaces during the rolling operat.ion;
Figure 3 is an enlarged sectional view oE a portion of
the seal assembly shown in ~igure 2;
¦l Figure 4 is a sectional view on a reduced scale similar
i to~Figure 2,~ showing the condltion Oe the seal assembly when thc
roll~undergoes axial shifting during the rolling operation;
Figure~5 is a sectional view showing a modified seal
and~seal~assembly for.use in ~a~"dry" application, where coolant
2~Q ~ ~ 1~ is~not~applied~to the rolI~during a rolling operation;
Figyre 6 is a sectional view similar to Figure 2 showing
I~a~modification to the seal end plate shoulder surfaces; and
Fig~ure ~7 i.s a seotional view taken a10ng lines 7-7 of
Figure~6.
2~5:;~ ~ Referring now to the drawings, and with initial
re~exence to~Figs. 1-4,~ there is shown at 2 a roll having an end
' ~face 4~and ajroll~neck with-a tapered i.ntermediate section 6
; ~1e~ad1ng~to a more gradually tapered~end section 8. ~ sleeve lO
~lis mounted on the tapered end section 8 and is fixed relative
3011~ ~ to the~roll~neck~by conventional means (not shown) for rotation
~the ~w~th Tee sleeve 10 has ar. outer bearing surface 12 whioh
5~ l
i
jis journalled for rotation wi-thin an interior bearing surface 14 .
f a fixed bushing 16 which is carried in a roll chock 18.
The sleeve ]0 rotates with the roll while the roll chock,
18 and the fixed bushing 16 are stationary. Oil in flooding
!~ quantity is fed continuously bet:ween the bearing surfaces 12 and
,l14. A circular extension 20 of the roll chock provides at iks
~bottom portion a sump 22 in which the oil emerging from the
bearing is continuously collected. The oil may be drawn away from
llthe sump through a suitable pipi.ng connection 24 to be recycled
llback to the bearing surfaces.
¦I Where the roll 2 is operating under "wet" conditions,
icoolant fluid is constantly flooding over the roll 2 and down
jover the end face 4. In spite of the centrifugal forces which
,tend to~throw the coolant off of the roll, some of the coolant
15~ tends to work its way along the roll neck in the direction of the
bearing. The objective of the seal assembly generally indicated
Iat 26 and`the~flexible neck se;al 28 which forms a part of the
earing assembly, is to prevent any of the coolant fluid from
rea=hing and~contaminating the bearing oil and, vice versa,
0~ preyéntlng loss~cf oil from the bearing.
In the embodiment shown in Figs. 1-4, the flexible neck
seal~28~includes a flexible circular seal body 30 having inner
~surfaces 32a,~32b adapted to be mounted in sealing engagement on
~the~tapered section 6 of the roll neck. The neck seal 28 is
25`~ ~ molded c~ R suitable resilient rubber~l.ike material. Preferably,
~he~seal body 30~is internally reinforced by an embedded combination
~ ,
o~a~cciled spring 34 and~a steel cable 36 as descri~ed and claimed
~ln U~.~S. Patent No~ 3,330,567 which is assigned to the same assignee
as~;~the present application.
1 ~ :,
~ ~ 7-
:
;. ~ ,
, ., .;, . .......... ... .... .. . . .. . ..
6~
,I The seal body 30 has an exterior cylindrical surface 38
liwhich is pa.rallel to the rotational axis "a" of the roll 2 when
lthe neck seal is in its mounted position as shown in Fig. 2. A
'.pair of axially spaced circular flexible flanges 40a, 40b are
S l,integral with and extend radially outwardly from the seal body 30
~at opposite ends of the exterior cylindrical surface 38. As is
best shown in Fig. 1, the radial length "la" of flexible flange 40a
is preferably less than the radial length "lb" of flange 40b, with
the dlfference between the two radial lengths being indicated at
~: "d". The dimension "d" will vary depending on the diameter of the ¦
seal body 30, the seal material, etc. The purpose of ha-riny a
: :~ differenae "d" in the radial lengths.of the flanges 40a, 40b is to ,
compensate for the distortion and stresses which the flexible seal
undergoes when it is mounted on the tapered section 6 of the roll
15 ~ ~tlneck. By having an initial difference "d" in radial lengths
between the two flexible flanges, after the seal is mounted on.the
roll ne~ck as;shown in Figures 2 and 4,:the affective radial lengths
,of~the~two~flange:s 40a, 40b~are equal. ~ -
In a wet appliçation; the 1anges 40a, 40b of the flexible
20~ `sèal are:each provided with circular flex.ible lips 42a, 42b. Each
: ~1exible~1ip~i~s~in*egrally joined to~nnd extends angularly outwardly
~awa~ rom the~outer e~ge 44a, 44b of its respective supporting flan;ge
referably:~the flexible lips 42a, 42b extend angularly in
opposite~directions away from the central portion of ~he seal body,
~25~ jthus~:making it d~:ificuLt:if not impossihle for the lips to roll
; l~under;~during axial displacement o the roll. This in turn makes i~
possible;to do ~way with the inclined shoulder sur~aces o~ the
prIor art seal~end~plate. Preferably, each 1exible lip is essen-
t1al.~identic~al~in construction. Acaordingly, and with specific
~:~30~ l~xefe~encé~to Fig.:~3, it will be seen that each flexible lip is
j~jolned~to~:~its~respective flexible supporting flange by a connecting
8-
s~
means which accorNmodates resilient flexure of the lip relative
to the flange. Preferably, this connecting means comprises an
intermediate radial web 46 whi.ch is of lesser thickness than the
~thickness of the flange 40b. The natural resiliency of the seal
l~material when combined with the reduced thickness of the inter- ;
¦Imediate web 46 allows the lip 42b to flex resiliently in relation
!~ to the flange 40b with minimum bending or distortion of the latter.
Preferably, the flexible lips 42a, 42b are provided
with a gradually diminishing thickness, with the minimum thickness,
~being adjacent to the outer edge thereof. In this connec-tion,
¦¦and again as is best shown in Fig. 3, each lip is preerably
provided with an outer face ~8, an inner face 50 and an end face
52. The outer face 48 is disposed at an angle relative-to, and
provides a continuation of, one surface 54 of the flange to which
¦¦the lip is integrally joined. The inner face 50 is disposed at
I!an angle relative to the outer face 48, and the end face 52 is
substantially parallel to the surfaae 54 while being disposed at
aout~e~and~obtuse~angles respectively relative to the outer and
,inner faces 48,~50. The juncture o the outer face 48 and the
2~0~ 1~end~face~5~2 provides a circular sealing edge 56.
In the embodiment shown in Figs. 1-4, the seal assembly
~Z6 includes the~ilexible neck seal 28 described above and in
;addition, a rigld circular seal end plate 58 which i5 mounted on
~ the roll chock 18. The seal end plate has a radially inwardly
- ~ 2s~ ~extending rigid flange 60 which is perpendicular to the rotational
axis "a" of the~roll 2. The inner edge of flange 60 is spaced
~radially from~the exterior cylindr1cal surface 38 on the flexible
¦seal body.~The~seal end plate 58 ur~her includes shoulders 62a,
62b extending~ln opposite dlrections ~rom the base o~ the rigid
. : .
1 ~
. ~ .
~ . .
!1~ ilange 60. Each of the shoulders 62a, 62b has a cylindric~l
~shoulder surface 64 which is parallel to the rotational axis "a".
The cylindrical shoulder $urfaces 64 surround the flexible seal
l~ flanges 40a, 40b and are arranged to be slidingly contacted by
li the flexible lips 42a, 42b.
The seal assembly 26 includes other features and
l components which will only be mentioned brie1y since they are
! common to known prior art constructions and thus do not form a
ipart of the present invention. More particularly, there are
ladditional fianges 66 extending radially outwardly from the
Ishoulders 62a, 62b of the seal end plate, an inner seal ring 68
I ~having resilient buttons 70 engaging the end face 4 o~ the roll
j,with the inner edge of the inner seal ring contacting the flexible
seal body as at 72, and an outer seal ring 74 surrounding ~he
!¦ inner seal ring 68 and having a drainage port 76 extending through
its lower side.
~ ~ . i
; During a rolling operation, the above-described
apparatus will operate in the following manner: the inner seal
;ring ~68, flexible neak seal 28 and sleeve 10 wilL rotate with the
~ro11 neck~. The outer seal ring 74, seal end plate 58, chock 18
¦and~bushing 16 WLll remain stationary. Lubricating oil will
constantly ~flow from between the bearing surfaces 12 and 14. Most
of this oil will be turned back by the rotating flinger 78 on
~the neck seal 2a and will thus be directed to the sump 22. Oil
25~ ~which succeeds in passing by the flinger 78 will be turned back
; ~by~the rotating flange 40b and will be prevented rom escaping
between the flange 40b and the shoulder sur~ace 64 by the flexiblel
lip 42b which seaIingly engages the shoulder surface 64. Likewiser
~the ma~or portion o the coolant applied to the roll 2 will be
~urned bac~ by, the rctating inner seal ring 68. Any coolant which
'J ~ ~ ` .
i - 10-
!
S~
i!succeeds in passing by the inner seal ring 68 will be turned back-.
,by the rotating fl.ange 40a on the neck seal 28 and will be
.prevented from passing between the flany~ 40a and its surrounding
,shoulder surface 64 by the flexible lip 42a.
l~ Some of the specific advantages provided by the fore-
going arrangement are as follows: the circular flexible lips 42a,
li42b slidingly contact and sealingly engage the surrounding shoulder
t,surfaces 64 of the seal end plate with a relatively light contact
., i
,pressure as compared with prior art arrangements. This is due
j'partially to the tapered reduced thickness of the lips 42a, 42b,
and partially to the manner in which the lips are joined to their
respective 1anges to accommodate resilient flexure of the lips.
T~is relatively light contact pressure.minimizes frictional wear
jof both the lips 42a, 42b and the shoulder surfaces 64, and also
Iminimizes any resulting frictional heat generated therebetween.
:These advantages;~translate directly lnto a~longer useful life of
bQth~the~neck~seal: 28 and the seal end plate 58.
By~allowing the lips~42a, 42b to fle~x resiliently in
;"relation:~toj:their:respective~supporting fianges 40a, 40b, the
' ~ ges~are ml~nimally~bent~or distorted by the surrounding seal end
plate~s~hQulders.~This allows the flanges 40a, 40b to remain
essentially~:paralLel to the radial seal end pla~e flange 60, and 1 .
thus~obviates or:~at least substantially minimizes the likelihood
that.the~flangés~40a, ~Ob will undergo permanent distortion.
j5 ~ jl;~ The ;a~gularly disposed lips 42a, 42b will be urged.
oùtwardly agai"st~thè shoulder surfaces 64 b~ centrifugal force.
~5;~ ¦~s~previous:ly mentioned,~`this affect will increase or decrease
¦ih~ ~ ct~proportion~to`the rotational speed of the roll, thus
; l~providing~peak~pressure at high rolling speeds, when it is most
- 30~ .~needed~
' ~
~ !
`:'',: ,~ ',''.'", .. - .. ,. ,.,.,. ,~ ' . ' , ,
1~ 10t~ 3~ ~
The arrangement of the seal end plate shoulder surfaces 64
in parallel relationship to the rotational axis "a" of roll 2 is
also seen as a decided advantage in that it allows the relationship
l~between the shoulder surfaces 64 and the circular flexible lips 42a,
S ,,42b to remain essentially constant regardless of the axial position
iof roll 2 with reference to its supporting chock 18. This is illus,-
lltrated by a comparison of E'igs. 2 and 4. In Fig. 4, although the
,Iroll 2 has been axiall~ shifted to one extreme, the radial relation-
¦lship of the flexible lips 42a, 42b to the surrounding shoulder
jlsurfaces 64 remains essentially the same, thus allowing the sealing
~relationship therebetween to remain constant. Also, and again withl
reference to Fig. 4, it will be seen that axial roll displacement can
.take place without any resulting roll under of the lips 42a, 42b,
,~ ,
euen though the shoulder surfaces 64 are not inclined or tapered.
~lS~ A further advantage is seen in the provision of flexible
seaL flanges 40al 40b of di~fferent radial lengths to compensate for
in~ernal stresses and distortions experienced by the seal body 30
,when:i~t~is mounted on the tapered section~6 of the roll neck. IIere
.again, this feature oontr1butes to a.constant and predictable seal1ng
20. ~ re1~t1onship between the lips 42a, 42b and the shoulder surfaces 64;
uring~subsequent~operation of the mill.
l~ :Referring now to Fiy. 5, an alternate embodiment of the
:invent1on is shown whioh is specially adapted for use in a "dry" I
application,~ i,.e., one where coolant is not being applied to the roll
~during the;.rol:L`ing operation. With this arrangement, the neck seal
~28~is~again provided with a pair of radially extending flexible
~langes~40a, 40b. How;ever, only flange 40b has a flexible lip 42b,
~arrociated~therewith.~ The~s~al end plate 58 has only one cylindrical .
~sh~ulder~sur~ace 64~surrounding the ~lange 40b and in sealing contac~
30~ with~the~lip 4:~b~. On the opposite side o~ the radial flange 60,
the serl end plate 6g forms an enlarged clrcular groove 80 with a
drainage port~81 at its lowermost sideO The flexible seal
~1ange 40a protrudes radially into the grooVe 80 but does not
:` ~
~ -12-
: ~ !,
frictionally contact any surEace on the seal end plate 58. This
, arrangement provides adequate sealing on dry app~ications where
,, the prime func-tion of the seal assembly is to contain oil in the
,~ bearing.
'I In the embodiment shown in Figs. 6 & 7, all of the
¦ components are essentially identical to those shown in Figs. 1-4,
with the exception that the interior shoulder surfaces on the end
ii plate shoulders 62a, 62b are threaded as at 82. ~he threads
j 82 urge the xotating flexible lip5 42a, 42~ away from the radial
1l flanqe 60, while at the same time providing a pumping action
¦¦ which directs fluid, either coolant or oil, away ~rom the lip/
terface
It is my intention to cover all changes and modifications
3l of the embodiments herein chosen for purposes of disclosure which
~¦ 151~ do not depart from the spirlt and scope of the invention.
I claim:
13-
