Note: Descriptions are shown in the official language in which they were submitted.
The present Inventlon relates to wet mo-tor fuel pumps
and, more partlcularly, to wet motor fuel pumPs of the type hav-
lng Inlet houslngs and pump elements that must be preclsely
allgned.
1 0
3~7
-
Prlor art wet motor pumps lnvolve a large number of prec1sion
parts requlr~ng preclse allgnment, assembly9 and operation wlth each other.
With slJch pr10r art wet motor pumps, the ~nlet end and outlet end of the
motor shafts are preclsely posltloned ~n the respective inlet houslng and
outlet llouslng so that the shaft a~is ls precisely flxed. SIJCh preclslon
shaft pos~tion1ng 1s required to prevent the armature w1nd~ngs from inter-
ferrlng wlth perlpheral structure such as the port plates, the magnets, and
even ~ith such precise shaft pos~tionlng ample tolerances are provlded to
account ~or wear.
Such constraints are compounded 1n a gerotor pump because of the
extremely small clearances that must be perpetually ma1ntained between the
t1ps of the mat1ng gears wlth respect to each other and to the perimeter of
the pump1ng cav1ty as well as the sides of each of the gears relatlve to
both axlal sides of the pump1ng cav1ty. Any degradat~on of the tip
clearance or slde parallellsm reduces the efflciency of the pump.
Another element reduclng the eff1ciency of the pump and lncreasing
the noise generated thereby ls the conventlonal drlve arrange~ent between
the motor and the dr~ven gear of the pump. Such ~r~ve couplings have here-
06
tofore been of the slot and key arrangement\requir1ng not only that the
shaft be prec1sely al~gned wlth the bore o~ the dr~ven gear, but also that
the key and slot coupl~ng the two are of slmilar prec~sion. The wear ~n the
slot and key arrangement not only is a known primary fa~lure mode~ but also
compounds the wear degradat~on ln teeth clearance and parallel1sm~
Accordingly, fùel pumps of the gerotor type are normally comparatlvely
expenslve due to the ad~ltlonal precis~on required there~n. Moreover, to
provlde the requlsite prec~slonD the gerotor parts are usually made lndepen-
dently and allgned separakely from the lnlet hous~ng.
A~Y~ ff~ N
The present 1nvention recognizes that the ends of the motor shaFt
can be supported ;n the Inlet and outlet housings so as to allow the mctor
shaft to have a limited self-allgnment with respect to the more precisely
poslt~oned pump~ng elements. The inventlon recognizes that it is des1rable
to precisely posltlon ~ust the pumping elenlents and just the outlet end of
the motor shaft, the lnlet end of the motor shaft being a110wed a sllght
self-al1~nment relatlve to the pumping elements to open up tolerances of the
1nlet end of the shaft relative to both the pump1ng elements and also the
inlet housing. The present invent10n recognizes that such features rnay ~e
a~forde~ by a novel bush1ng supportlng the outlet end of the motor shaft
S ;~f
relative to the outlet ~u~ks~, the 1nlet end being thereby allo~ed to
effect a sl~ght self-adjustment relative to a known pivot po1nt n The pre-
sent 1nvent10n ~urther recognl7es that such precise locat10n of a polnt on
the shaft zx1s can be effected by an lnexpens1Ye tubular bush1ng haviny
ra1sed portion ln the form of a crown mak1ng a line contact w1th a substan^
t~al port10n of the bore support~ng the outlet end of the shaft. The pre~
sent ~nvent10n therefore contemplates provlsion of such a bushlng ln the
bore of the outlet hous1ng 1n a rnanner preYent~ng rotztion of the bush1ng~
but nevertheless allow1ng 1t to t11t end-for-end wlth the outlet end of the
motor shaft.
The present ~n~entlon further recogn1zes that the lnlet hous1ng
may be comb1ned wlth the structure normally hous1ng the pumplng elements 1n
a manner result~ng 1n a one-p~ece combined 1nlet and pump hous~ng~ such
structure ut111z1ng the fact that the prec~s10n between the lnlet end of the
~otor shaft 1s relaxed relat1ve to the convent10nal 1nlet hous1ng 1n
cooperatlon wlth the relaxed preclsion relat1ve to the pump1ng elements.
In accordance with the present invention, a bushing
is provided for supporting the outlet end of an armature motor
shaft in sections of an arcuate bore of an outlet housing of a
fuel pump. The bushing has an exterior periphery with a
raised portion extending circumferen-tially thereabou-t and
radially away from the outlet end portion of the armature
shaft. The raised portion is press-fitted into the bore to
permit a pivoting movement of both the bushing and the shaft
end rotatably supported therein, the line contact between the
raised portion and the bore allowing the former to slip
relative to the later by pivoting about a known axial point.
A key and slot arrangement couples the bushing to the outlet
housing so as to prevent relative rotation therebetween, the
key and slot having sufficient circumferential and radial
clearance to accommodate the slight pivoting of the shaft
axis.
According to the present inven-tion therefore there
is provided a wet motor gerotor fuel pump for pumping fuel
from a fuel source to an internal combustion engine
comprising: a pump case having one end, an opposite end and a
flow axis therethrough, said pump case fur-ther comprising an
inlet end bore at said one end adap-ted to communicate wi-th
said fuel source; an inlet chamber adjacent said inlet end
bore; a motor chamber located in said opposite end of said
pump case; a pump chamber interposed said motor chamber and
said inlet chamber; first means for sealing said pump case,
said first means for sealing located at said opposite end of
said pump case; inlet housing means mounted in said pump
chamber, said inlet housing means comprising an annular hub
protruding into said inle~ chamber, said inlet housing means
further comprising a gero-tor cavity about a gerotor axis
located parallel to and displaced a prede-termined dis-tance in~
-- 4
an eccentric radial direction from said flow axis; outlet
housing means having pump outlet means adapted to be
communicated with said internal combustion engine and further
comprising second means for sealing coupled to said first
means for sealing; electric motor means comprising armature
means comprising an armature shaft having a shaft axis and a
first and a second end rotatably supported, respectively, at
said inlet housing means and said outlet housing means, said
armature means further comprising drive hub means having first
tang means extending in a first radial direction relative to
said armature shaft; and gerotor pump means located in said
gerotor cavity, said gerotor pump means comprising an inner
pump gear, an outer pump gear, and second tang means loca-ted
on one of said inner and outer pump gears, said second tang
means further extending in a second radial direction radially
offset from said first radial direction and adapted to be
drivingly coupled to said first tang means such that said fuel
pump pumps fuel from said fuel source into said inlet chamber,
through said gerotor means past said electric motor means into
said outlet housing means substantially along said flow axis
to sald internal combustion engine; said outlet housing means
further comprising: a cylindrical bore located in said ou-tlet
housing means, said bore havi.ng a central axis; a self-
aligning bearing bushing mounted in said cylindrical bore for
positioning said second end of said armature shaft relative to
said central axis of said cylindrical bore, said self-aligning
bearing bushing comprising an annular body having an axis and
a crowned periphery portion with said crowned periphery
portion extending radially away from said axis, said crowned
periphery portion being in contact with said cylindrical bore,
said annular body being generally circular in cross-section;
and a cylindrical bore axially aligned wi-th said axis of said
annular body, said cylindrical bore adapted -to receive said
second end of said armature shaft; and anti-rotation
means coupling said self-aligning bearing bushing and said
outlet housing means to prevent circumferential rotation of
said self-aligning bearing bushing relative -to said outlet
housing means such that misalignment of said second end of
said armature shaft rela-tive to said central axis of said
cylindrical bore in said outle-t housing means is permi-tted by
said crowned periphery portion of said self-aligning bearing
bushing pivoting in said cylindrical bore of said outle-t
housing means in response to an axial alignment movement o~
said first end of said arrnature shaft at said inlet housing
means while permitting said second end of said armature shaft
to rotate within said cylindrical bore of said self-aligning
bearing bushing. Suitably, said anti-rotation means comprises
a key mounted in said outlet housing means and a slot located
in said self-aligning bearing bushing, said key having a
radial clearance and a circumferential clearance from said
slot to permit said pivoting and alignment movements.
Preferably, said first end of said armature shaft i.s drivingly
coupled to a gerotor pump, and said anti-rotation means
comprises a shoulder loca-ted on said self-aligning bearing
bushing, said shoulder being of a predetermined width, and a
counterbore in said cylindrical bore of said ou-tlet housing
means, said counterbore being of a predetermined depth greater
than said predetermined width of said shoulder, said shoulder
and said counterbore cooperating to provide axial movement of
said self-aligning bearing bushing in one direction relative
to said outlet housing means, said shoulder having a slot
therein; and said counter bore having a key por-tion therein,
said slot and key portion cooperating to prevent rotational
movement of said self-aligning bearing bushing with respect to
- 5a -
said cylindrical bore in said outlet housing means.
Desirably, said anti-rota-tion means comprises a key mounted on
said self-aligning bearing bushing and a slot located in said
outlet housing means, said key having a radial clearance and a
circumferential clearance from said slot to permit said
pivoting and alignment movements. Suitably, said first end of
said arma-ture shaft is drivingly coupled to a gerotor pump,
and said anti-rotation means comprises a shoulder located on
said self-aligning bearing bushing, said shoulder being of a
predetermined width, and a counterbore in said cylindrical
bore of said outlet housing means, said counterbore being of a
predetermined depth greater than said predetermined width of
said shoulder, said shoulder and said counterbore cooperating
to provide axial movement of said self-aligning bearing
bushing in one direction relative to said outlet housing
means, said shoulder having a key thereon; and said
counterbore having a slot portion therein, said key and slot
portion cooperating to prevent rota-tional movement of said
self-aligning bearing bushing with respect to said cylindrical
bore in said outlet housing means.
The present invention thus provides an improved
bushing for an end of a motor shaEt of a fuel pump.
The present invention also provides a bushing of the
foregoing type for precisely centering a point on the shaf-t
axis while allowing a slight pivoting about such known point
in response to an axial alignment of the shaf-t.
The present invention again provides a bushing of
the foregoing type wherein the raised portion is permitted to
slip axially in the supporting bore to effect -the necessary
pivoting abou-t an axial point.
The present invention further provides a bushing of
the foregoing type wherein the housing cooperates with the
- 5b -
~ 7
bushing to limit and substantially prevent axial rotation
therebetween.
The present invention also provides a bushing of the
foregoiny type wherein a line contact between the raised
portion of the bushing and the bore establishes an end chamber
in the outlet housing.
The present invention again provides a bushing of
the foregoing type wherein the anti-rotation structure is a
slot and key arrangement having sufficient circumferential and
radial clearance between the slot and key to permit the
foregoing end-for-end alignment of the motor shaft while the
raised portion slips relative to the bore as it pivots about a
fixed axial point.
The present invention further provides a wet motor
pump having a new and improved inlet housing.
The present invention also provides an inlet housing
of the foregoing type that is combined with a pump housing
into a one-piece diecast unit requiring no secondary
machining.
O The present inven-tion again provides a one-piece
inlet and pump housing of the foregoing type that replaces
four separate precision parts.
The present invention will be fur-ther illustrated by
way of the accompanying drawings wherein:
Figure 1 is an end view of one embodiment of a wet
motor gerotor fuel pump having certain features provided in
accordance with the presen-t invention;
- 5c -
i'7
~ gure 2 ls an axial cross-sectlonal vle~ o-f the gcrotor ~uel pump
of Flgure l taken along llne 2-2 th~reof;
F~gure 3 is a trafisvcrs~ radial cross-sectiondl view of the sero-
tor fuel pump of Figure 2 taken along line 3-3 ther~of;
Fiyure 4 is a -transverce radial cross-sectlonal V~e~J of th~ ~ero-
tor fuel pump of F~gure 2 takcn ~llong line ~-~ thcreof;
Figure 5 is an enlarged and exaggerated vl~ of portlons of an
arrnature shaft and inner gerotor purnp gear;
Figure 6 15 a cross-sec~iondl v~eh of the outlet housing with an
outlet check valYe and vent valve of the serotor ~uel pump of Fi~ure l taken
along 11ne 6-6 thereof;
Figure 6A is a crGss-s~ct1Onal vie~ o' ~n imperfect valve seat and
ball valve of the vent valve of Figure ~ ta~n alon~ l~ne 6A-6A thereof;
Figure 7 is a view of the yerotor fuel p~mp of F~gure 2 taken
1~ along 11ne 7 7 thereof;
Flgure 8 ls a fragmentar~ plan Vi~.Y of ~ portion of Flgure 2
showing the orientat~on of the outlet houslng bJ~ the use of an index1ng tab
pos5tioned between the two motor magrlets;
: Figure 3 is an explode~ vie~ n perspcctiv~ of the gerotor ~uel
pump shown 1n Flgures 1 through 8;
F~gure 9A ls a persp~ctive vle~ of the coupl~ng arrangement of the
armature shaft and t5~e ~nner gerotor pump gear of Figures 1 througll 9;
Figure 9~ ~s d perspective vl~J uf an alternat~ve 5ess preferable
embodlment of the keeper of F1gures 7 and 9;
Flgure 10 Is a partlal sectlonal vlew of a portlon of
an alternatlve outlet houslng, showlng a vent-rellef valve and a
bushlng for rotatably supportlng an end portlon of the armature
shaft;
Flgure 10A Is a perspectlve vlew of portions oF an
alternatlve verslon of the suPport bushlng and outlet houslng of
Flgure 10 showlng the slot and key arrangement thereof for llml-
tlng clrcumferentlal rotatlon of the bushlng;
Flgure 11 Is a perspectlve vlew of a pop-off valve of
the vent-rellef valve shown In Flgure 10;
Flgure 12 Is a top vlew of the alternate outlet houslng
of Flgure 10;
Flgure 13 Is a bottom vlew of the Internal conflgura-
tlon of the alternate outlet houslng of Flgure 12;
Flgure 14 Is a cross-sectlonal vlew through Just the
alternate outlet houslng of Flgures 10, 12 and 13 taken along
llne 14-14 of Flgure 12;
Flgure 15 Is a view taken through Just the outlet hous-
lng of Flgures 10, 12, 13 and 14 taken along llne 15-15 of Flgure
12; and
Flgure 16 Is an e~ploded vlew In perspectlve of certaln
features of the alternate outlet houslng assembly, certaln parts
thereof belng broken away.
Wlth reference now prlmarlly to Flgures 2 and 9, there
Is shown a wet motor gerotor pump assembly or pumP 10 for recelv-
lng a fluld, such as fuel from a source such as a fuel tank (not
shown), and delIverlng pressurlzed fluld to a utlllzatlon devlce,
36
such as an Internal combustlon englne (no-t shown). The wet motor
gerotor pump assembly or pump 10 Includes
- 7a -
L~
a tubu1ar stepped case 12 ~enera~ly enclos1ng an lnlet and purnp hous1ng 14,
a gerotor pump assembly 1~ a motor -Flu~ ring 17, a pump outlet or port plate 180
and being sealed agalnst an outlet hous~ng 18 w~th an electr-lc motor
asserrbly 20 supported L~etween the inlet and pump hnuslng 14 and the outlet
hous1ny 18.
The tu~ular stepped case 12 term~nates at one end in a sealing lip
22 flanged lnwardly to seal aga1n~t an outwardly extend~ng annular shoulder
24 of the outlet hous~ng 18. To~/ards 1ts other end~ the tubular stepped
case 12 1ncludes an outer bore 26 ~yenerally deF~nlng a motor chamber 289 ~
pump bore 30 opt~onally 5tepped lnwardly from the outer bore 26 at an annular
shoulder 32 and generally defining a pump chamber 34, and an lnlet bore 3h
stepped lnwardly from both the outer and pump bores 26 and 30 and generally
def~nlng an ~nlet cha~ber 38. The inlet cham~er 38 ~s adapted to be com-
munlcaten tn a known manner wlth a fuel source (not shown) such as ~y a
known fluld coupl1ng, condult and fllter (not shown).
Made of a one-plece d~ecast zinc structure, the 1nlet and pump
houslng 14 has a cyl~ndr1cal outer per~phery 40 fltted into the pump hore In
the pump chamber 34 of the tubular ste~ped case 12. At an lnlet end
thereof, the 1nlet and pump houslng 14 termlnates ln a tubular hub 4Z
proSrud1ng 1nto the tnlet bore 36 and inlet chamber 38 of ~he tuhular
stepped case 12 and also has a stepped bore 44 of a structure and flJrlctlon
to be descr~bed ln greater deta11 here1na~ter. The cylindr1cal exterlor q5
of the tubular hub 42 1s separated hy an annular space 46 from an enclrcllng
annular sprlng wash~r 48 hav1ng an inner d~ameter portlon 50 seated aga1nst
an annular hub seat 52 protrud1ng axlally 1nwardly ~rom the lnter~or of the
tubular steppéd case 12. The annular spr~ng washer 48 also has an outer
dlameter port~on 54 captured ax~ally and rad~a11y ln an annular counterbore
56 formed on the 1nlet slde 58 of the inlet and pump hollslng 14 Just inboard
of the cyl1ndr1cal outer per1phery 40 thereof.
--8--
The electrlc motor assem~ly 20 includes an arma~ure shaft 60
hav~ng an arm~ture sh~ft inlet end 62 and ~n armature shaft outlet end ~4,
each sha~t end betng notatably supported by a respecttve tut)ular bush~ng or
beartng ~6 and 68 sllp-f1tted thert-on and resiliently supported by 0-rlngs
70 and 723respectively~engaging a bore 74 tn the lnlet and pump houslng 14
and a bore 76 ~n the outlet housing 18. The tubular bushing ~ ~s lubrl-
cated and cooled by fuel 1n the inlet chamber 38, and the tubular bushlng 68
Is lubr~cated by fluid ~ed through axtal slots 75 spaced ahout Lhe
pertphery of the bore j~. The armature shaft 60 ts pos~tioned generally
along a central flow axls 78 throu~1h the wet motor g~rotor pump assembly 10
, D ~ 5 D
and ~s pos1t~oned therealong hy a thrust washe~ 18~ belng ac~lvely~against
the thrust washer seat 184 which is part of the pump outlet or port plate 180
by means of
the magnettc attraction acttng between the m~gn~ts ~40 and 242 and the
armature stack. T~le bearing 66 at the inlet is positioned by means of a
shoulder
80 extendlng outwarclly ~rom the tubular ~ushlng 66 and an annular shoulder
82 extendlng inwardly from the tuhular huh 42 to thereby capture the 0-ring
70 therebetween.
Atlapted to rotate tn the motor chamber 28D the electr~c motor
assembly 20 tncludes an armature ~4 made of a plural~ty of arm~ture wtndlngs
86 wound throu~h a plural~ty of slotted armature l~nlnat~ons (not shown)
press f~tted on a knurled portlon (not shown) of the armature shaft 60. Each
armature w1nd1ng 86 has respective f~rst and second ends term1nated ~n a
known manner at a commutator 88 adapted to tlectr1cally and slld~ngly engage
a pa1r of dlametrtcally opposed commutator brushes 90 and 92 electrtcally
coupled to respect~ve cup-shaped term~nals ~1 and ~3 The brushes 90 and 92
are urged aga1nst the commutator 88 along a brush displacement axls 94 by a
respect~ve ftrst and second brush spr~ng ~6 and 98.
Press fltted on the knurltd portton of the armature shaft 60
ax1ally outboard the oppostte ends o~ the armature 1amlnattons are a ftrst
_g_
and a second end flber 100 and 102, each llavlng eight f1ngers 104 extendlr
rad~ally out~ards from a fibrous central tubu1ar hub 10fi spaced equ~angu-
larly thereabout, each flnger 104 hav~ng at lts t1p an ax~al1y extendln~ t
108 extendlng axlally ~n~lards towards the armature lamlnat~ons to prov~de
stand ofF therefrom. The outward axial side of each fin~er 104 has a smoo
curved outer surfdce therealong so as to non-abras~vely engage and support
the end loops of the armature wind~ngs 86. The f~brous central tubular hu
106 of the end flber 102 has an ~nnular thrust shoulder 110 extend~ng
radlally outwards therefrom and termina-tes ax~ally ln a pa~r of drlve tang
or dogs 112 and 114~ best seen in Flgure 9, in the form of dlametrlc311y-
opposed arcuate sections extending ax~ally towards and ~nto the 1nlet and
pump housing 14.
As may be better un~erstood with reference to Flgures 2, 39 and
the lnlet and pump housing 14 has a counterbore 116 opening towards the
armature 84 and def~n1ng a gerotor cavity llS and also has a central bore
120 therethrough~ The counterbore 11~, the gerotor cavity 11~, and the
central bore 120 are concentric about an offset axis 122~ ~est seen in
f~gures 3 and 99 having a predeter~1ned radial offset lZ4 from the central
flow ax~s 7~ along a first radial directlorl generally perpend~cular to the
brush displacement ax~s 94. As may be better understood with reference to
Figures 2~ 4, and 99 an oblong depress~on 126 and an oblong aperture 128 ar
prov~ded in a bottom surface 130 of the counterbore 116 and are disposed
generally concentrically ahout the central bore 120. As best seen 1n ~19ur
4, the inlet slde 58 of the inlet and pump housin~ 1~ has an oblong lnlet
depresslon 132 extendiny ax~ally theretn,A first oblong inlet depression
132
on the inlet side 58 communlcates wlth the oblong aperture 128 in the
bottom ~urface 130 of the counterbore 116 and a second oblong inlet
depresslon 136 on the inlet side 5~ of the inlet and pump housing 14
which also
con~un~cates with the entire oblong aperture 128 in the bottom surface 130.
-10-
_________ ._ _ ,_ _
The f1rst and second ~nlet depress~ons 132 and 136 cooperate to prov1de
unpressllr~zed flu~d to the gerotor cav~ty 118 for both pr1ming the gerotor
pump assembly 16 and provid1ng flu~d to be pressur1zed thereby~
Located 1n the gerotor cavlty 118 of the gerotor pump assembly lb
are an 1nner pump gear 142 and an outer pump gear 1449 shown only 1n Flgure
3. The 1nner and outer pump gears 142 and 144 have respect1ve ser~es of
lnner and outer pump teeth 154 and 15~ and pump teeth spaces 158 and 160
1nterven~ng therebetween. The lnner pun~ teeth 154 of the inner pump gear
~Q ~
142 ~r~formed to pumplngly seal an~ engage the outer pump teeth 156 and
teeth spaces of the outer pump gear 144, wh11e the outer pump teeth 156 of
the outer pump gear l44 are formed to pumpingly seal and engage the inner
pu~p teeth 154 and the teeth spaces 158 o~ the inner pump gear 142. The
outer pump gear 14~ has a cyllndrical external perlphery 162 that ts s11p-
f1tt1ngly rece1ved by and pos1tioned in the counterbore 116 of the gerotor
cav1ty 118. The inner pump gear 142 has a cen~ral bore 164 therethrough
wh1ch, as may be better understood with reference to F19ures 2 and 57 has a
tapered open1ng 166 ~aclng the bottom surface 130 of the counterbore 116 of
the ~nlet and pump hous1ng 14. The internal diameter ~f the inner gear central
bore
164 ls sl1ghtly greater (e.g., 0.001 lnches) than the external dlameter of
the armature sh~Ft 60 pass1ng therethrough and the ax1al length of the 1nner
gear central bore 164 is selected to be cQmDaratively short ~e.g., 0.005
inches
w1th respect to the lnternal d1ameter thereof so as to allow the armature
shaft 60 to p1vot sllglltly end-to-end relative to ~he inner ~ear
central bore l64
and thereby allow the 0-rin~ 70 to self-align the armature shaft 1nlet end
62 1n the bore 74 of the tubular hub 42. Such self-al19ning allows the
armature shaft 60 to effect small angles w1th respect to the central flow
DX15 78J such an~les lncreas1ng w1th 1ncreaslng manufackur1ng and assembl1ng
tolerances.
-11-
Wh~le thus allo~ed to self-al1gn relative to the lnner pump gear
142, the armature shdft fiO, as better seen ln Ftgures 3 and 9A~ nev~rtheless
dr~ves the Inner pump gear 142. The ~nner pump gear 142 has a palr of drl-
ven tangs or doys 172 and 174 extend~ng radially ~nwar~s therefrom ~nto the
dr~ve coupllng cav~ty 170. Form1ng a dr1ve coupl1ng 177D as best seen ~n
Flgures 3 and 9A, each bf the drive tangs 112 and 114 have an lncluded angle
of approxlmately one hundred and e1ghteen degrees ~118), and each of the
dr~ven tangs 172 and 174 have an tncluded angle of about f~fty-e~ght degrees
h~v 6
(58). The four tangs 112, 114, 172 and 174 thereby~Y~d total c1rcum-
ferent~al clearance of approx~mately e~ght degrees (~). 5uch clearance
allo~ls suff~ctent c~rcumferent1a1 plav to permit easy assembly of the clrlve
coupl1ng but also sllght ax~al misali3nment thereo~ to allow the end-for-end
self-al1gnment of the armature shaft ~0 relat~ve to the inner pump gear 142.
Complet1ng the gerotor pump assembly l~ are an annular pump
outlet or port plate 180 and a thrust washer 182 made of Teflon loaded
Ultem. The
pump outlet plate 180 has an annular thrust surface 184 eounterbored tnto
the outlet slde 186 th~reof and d bore 188 therethrough of a diameter suf-
f~ctent to allow the dr1ve tangs 112 and 114 of the fibrnus central tubular
hub 106 to freely pass therethrough w1th a suitable clearance (e.g., 0.005
lnches).The annular pu~p outlet pla~e 180 also has a cylindrical outer
periphery
190 and an annular rad~al groove lS2 extending tnboard therefrom, the outer
perlpher21 surface 190 belng receiven in the outer bore 26 of the tubular
stepped cas~ 12 ~nd be~ng seated agatnst the face of the annular shoulder 32
there~n, provld~ng both rad~al ~nd ax~alp~sitioning relative to the m~tor flux
ring 17. The thrust washer 182 ts pressed against the annular thrust sur-
face 184 of the pump outlet plate 180 by the annular thrust shoulder 110 of
the f1brous central tubular hub l06. The thrust washer 182 has a palr of
dlametrlcally-opposed arcuate tan~s or dogs 193a and 193b extend~ng radlally
lnward to engage and be dr1ven by the dogs 112 and 114 of the fihrous
central tubular hub 106~
-12-
~ t7
On an axlal slde fac~ng the inner and outer pump ~ears 142 and
144, the pump outlet plate 180 also has an oblong depression 196
and outlet aper-
ture 19~ ~enerally rnatch~ng the s~ap~ and posit~on of the oblong depress~on
126 and the oblong aperture 128 ln the hottom surface 130 of the counterbor
~JD
116 of the gerotor cav1ty 118 of the inlet cm~ pump houslng 14. To afford
proper pur~ prlrn1ng and other deslrable pumping characterlstlcs, the oblong
aperture 128 an~ the oblong depression 196 are comnun~cated through,
respect~vely~ bores 120 and 188 by approprlate radial slots 2no and 202, as
best seen ~n Figures 2 and ~ oreover, to prov~de a sultable outlet port
for flu1d purnped to a f1uld pressure in -the gerotor cavi-ty 118, the
annular pump
outlet plate 180 has ~he oblong outlet aperture 198 formed therethrough
and posi-
t~oned and shaped to correspond with the oblong depress10n 126. To proper1.
posit~on the pump outlet plate 180 circun~erentlally w1th respect to the
~nlet and pump hous1ng 149 a pa~r of locAtor plns 204 and 2~6 are afflxed
thereto to extend ax1ally ~ronl .~n annular rad~al surface 208 to engage
suitable holes 205 and 207 throuqh an annular rad~al surface 209 of the pum
outlet plate.
Pressure flu~d from the oblong outlet aperture 198 of
the pun~ outlet
plate 180 is gulded there~rom anrl protected from the wtndage ef~ects of the
armature 84 by a tunnel and magnet keeper ~evice ZlC, best seen ~n F1gures
7 and 9. The tunnel and magnet keeper devlce Z10 conststs of a ftrst flow
channel or passage 211 shielded from the armature w~ndage extendlng substan-
t~ally the ent1re ax1al length of the motor chamber 28 between the pump
outlet plate 180 and the annular st-oulder 24 of the outlet housing 18.
Shaped generally ~n the form of an ~nverted staple, the tunnel and magnet
keeper dev~ce Z10 has a central brid~e port~on 212 bounded by a palr of leg
port~ons 214 and 216. The central bridge portion 212 has a sl~ghtly convex
shape, as seen from a po~nt external to the pump, to match the c~rcular con-
tour o~ the per~phery Qf the arrnature ~4, and the palr of le~ portlons 214
and 216 extend radlally outwards from the central br~dge portlon 212 to seal
-13-
on an inner per~pheral surface 218 oF -the cylindrical magnetic mo-tor flux
rlng 17. The flux rlng I~ also extends substant~a11y the entlre axSal
length between the pump out1et plate 180 and the out~ardly ~xtend~ng annular
shoulder 24 of the outlet housing 18.
To allow substantially unlmpe~ed flo~/ of ~ressure fluid from the
oblong
outlet aperture 198 ~nto the tunnel an~ magnet keeper device 210 wh~le also
lmpart1ng a des1red clrcumferentlal posltlo~ to th~s ~evlce, the lnlet end
222 thereof 1s prov~ded w1th two ~x1ally extending protruslons 224 and 226
spaced radlally apart to provl~e a flu~d ~ntrance 22a therebetween. The
I0 axial protrusion 224 terminates ln a butt end 230 abuttln~ dlrectly against
the annular radlal surface 209 of the pump outlet plate l~0. The ax1al
protrus1On 226 termlnates ~n a stepped tab 232 ilavlng a butt end 232a
abutt1ng against the annular radial surface 20~ and a pin ~ortion 232b
ex*ending
~nto the outlet side of khe hole 207 provided to properly orlent the pump
outlet plate I80 w~th the 1nlet and pump hous1ng 14 as aforement1Oned.
The leg port~ons 214 and 2I6 of the tunnel and magnet keeper
devtce 210 cooperate w1th a pa~r of tabs 234 and 236 extending circumferen~-
t1ally outwards from the respective axial protrus~ons 224 and 226 to pro-
perly posit~on the palr of crescent shape~l motor magnets 240 and 242 both
c~rcumferent1ally and ax1ally w1th respect to the armature ~4. As may be
better understood w~th reference to Figures 7, 8 and 9, each crescent shaped
~otor magnet 240 ~nd 242 ls bounded along its Axtal length ~y a f1rst and a
second set of ~uxtaposed Dx1al surfaces 240a, 240b, 242a and 242b. and each
motor magn~ 240 and 242 ls bounded at its 1nlet and outlet ends by respec-
t1ve end surfaces 240c, 242c, 240d and 242d.
In assembly, the tunnel and magnet keeper devlce ?I0 ls f1rst
lnserted so that the ~ pln port~on 232b thereof is poslt~oned ln the
locator hnle 207 of the pump outlet plate I80. Thereafter, the crescent-
shaped motor magnets 240 and 242 are ~nserted so that the axlal surfaces
240a and 242a respect~Yely abut the leg port~ons 2I4 and 2I6 ~nd the end
-14-
surfaces 240c and 242c abut the ta~s 2~4 and 2~6. To properly space the
~otor magnets 240 and 242 from the outlet port plate 180 and provlde a
second ax1al channel 211a therebetween~ a Y-shaped compression spr1ng 246 ts
then inserted bet~"een the second set of juxtaposed ax~al surfaces 240b ~n~
2~2b to urge the ax1al surfaces 2~0a and 2~2a c~rcumferent~lly 1nto
abutt1ng contact with the leg port1Ons 214 and 21h~ of the tu~el ~ld
magnet keeper device 210.
F1nally, the outlet hous~nq 18 is inserted ~nto the tubular
stepped case 12. The c1rcumferentlal orientatlon of the outlet houslng 18
j5 ~pgr"t)
b~t~g determ1ned relat1ve to the tunnel and ~g~nt keeper dev1ce 210, as
best seen 1n F1gure 8, by an arcuate tab 2a8 extend1ng between the ax1al
surfaces 240b and 242b!of the crescent shaped motor magnets 240 and 242. A
pump outlet port or fitting 252, through the outlet housing 18, is
thereby aligned
along the same axlal plane 1ntersecting the center of the tunnel and magnet
IS keeper dev1ce 210 and the center of the outlet aperture 198 through the pump
outlet plate 180.
The ~orego~ng proper circumferent1al or~entation of the outlet
housing Ia relat1ve tn the tunnel and magnet keeper device 2l0 perm1ts a
flow of pressurized fluid smcothly ther~hrou~h directly fr~m the outlet aper-
ture 198, through the f1rst flow passage ~ to the pump outlet port 252
the outlet hous1ng 18.
It has been found through exper1mental test results, under stan-
dard condlt~ons, that the forego1ng apparatus substant1ally 1mproves pu~p
performanoe. Compared wlth wet pu~ps of sim11ar s12e and capaclty~ the
foregolng wet motor pump assembly prov1ded the des1red flu1d pressure at
substantlally 1ncreased flcw rates w1th substantlally decreased armature
currents. For examp1e, 1n one typ1cal appl~cat~on to a convent10nal
passenger car 1nternal ccmbust10n eng~ne~ flow rates were uniformly
~ncreased by at least three gallons per hour wh11e the correspond~ng arma-
ture currenlts were decreased at least twelve percent (l2%).
15-
Some portlon of this Improvemen-t Is attrlbuted -to
merely provldlng the axlal -Flow channel, such as the magnet
keeper 21Oa of the type shown In Flgure 9B. Such a keeper has a
central brldge portlon 212a abuttlng radlally outwards agalnst
the flux rlng 17 and bounded by a palr of leg por~lons 214a and
21~a openlng radially Inwards towards the armature 84. However,
such a keeper would allow the armature wlndage to Induce radlally
orlented hydraullc curls In the flow channels 211. But such tur-
bulence would reduce the effectlve cross-sectlonal area of the
axlal flow channel 211 to a small portlon of the actual cross-
sectloned area thereof. To avold such curls and turbulence and
substantlally Increase the effectlve area, the tunnel and magnet
keeper devlce 210 of the preferred embodlment Is provlded so that
the central brldge portlon 212 thereof shlelds the flow
therethrough from the armature wlndage. Should further Improve-
ments be deslred to avold hydraullc curls Induced wlth an orlen-
tatlon In the channel 211 by the flow restrlctlon Imposed by the
clrcumferentlal wldth thereof, the channel 211 could be further
subdlvlded Into subchannels of a plurallty of tubes or slots.
Such subchannels would provlde a lamlnar flow substantlally
Increaslng the effectIve cross-sectlonal area of the flow to the
actual cross-sectlonal area of the channel.
As best seen In Flgures 1 and 6, the outlet houslng 18
made of a molded plastlc, such as Ultem, Includes the pump outlet
vaIve 250 wlth the tubular outlet port or flttlng 252 adapted to
be coupled to an Internal combustlon englne. The tubular outlet
flttlng 252 has an Internal outlet PaSsage 251 wlth a slotted
seal 253 fltted Into an outlet bore 254 to enclose a ball valve
255 of a one-way check valve 256 thereln. The outlet houslng 18
provldes an annular seat 257 cooperatlng wlth the ball valve 255
to provlde the one-way check valve 256 whlch serves to prevent
backflow from the englne Into the pumP. To allow normal flow
from the pump 10 to the englne, the tubular outlet flttlng 252
termlnates In four tapered prongs 258 formlng slots 259 therebe-
tween, the tapered prongs 258 normally restralnlng the outward
- 16 -
3~7
movement of the ba I I va I ve 255 and the s I ots 259 a I I ow I ng the
fuel to f low out
1 5
ZO
Z5
3~
- 16a -
~ 6~
therebet~een. The angle formed by the tapered prongs 2~ is such as to
cradle the ball valve 255 so as to prevent oscillat10n of tl1e hall at cer~
ta1n flow rates~
A further feature o~ the ~et mot~r pump assem~ly is d vapor
vent valve 260 prov~ded in the outlet i-ousing 1~" as best seen in Flgures 6
and 6A. The vapor vent valve 260 ls locate~ diametrically opposite the
outlet valve 250, and lncludes a ball Z62 erlclosed ~n a valve bore 2~ by a
tubular vent f1tt~ng 266 havlng a ven1: passage 268 therethrough and having
an annular hub 270 seated agalnst an annular seating surface 272 of the
outlet housing la. A helical spr1ng ~74 blases the hall 26Z a~ay ~roln a
shoulder 276 encircling an annular internal hub 27~ of the tubular vent
fitting 266 and towards an imperfect seal in the form o~ a s~aure seat 280,
best seen ln F~gure 6A, at the end GT 1~ vent bore 282 forme~ ln the outlet
hous1ng 18. ~Ihen in cnntact h~ith the square seat 280, the ~all 262 touches
the square seat 280 at only four points 2~4a, 2~b, 284ct and 284dg such
arrangement prov~d1ng four sultahle bypass passages 2~aD ~86b, 286c, and
2~6d. With this arrangement, a vapor pressure oeveloped by the gerotor pump
assembly 16, especially t~uring self-pr1mlng thereof~ is unloaded through the
bypass passages 286a, 286b, 286c~ ar,d 286d unt~l liquid reaches the output
s1de of the pump1ng elenlents and the vent ~cre 282. Thereafter, the flu~d
pressure on the ball 262 w111 overcome the bias thereon by the hel~cal
spring 274 to seat the ball Z62 on the annular lnternal hub 278 formed at
the ~nboard end o~ the tubular vent fitting 266, thereby closlng the vent
passage 268 ancl allow~ng normal pumplng operation and outlet through the
2~ outlet port 252.
The square seat Z80 1n the forego1ng vapor vent valve 260 may be
replaced by other sultable non-circular, or imperfect, valve seats ~nclud1ng~
for example, partlally-c1rcular valve seats as might ~e effected by a c~r-
cular valve seat havlng ax1ally extend1ng slots therethrough.
-17-
A further appllcat~on of an ~mperfect valve seat is ~n coMbinatlon
w~th a vent-rellef valve 290 shown Inolded into the alternate outlet housing
19 ~n Figures 10 and 11. As mdy be better understood hith reference
thereto, 3 ball 292 is enclosed in a bore ~94 provlded in the outlet hous~ng
19, the bore 294 def~n~ng theretn a valve chamb~lr 295. One end of the bore
~g4 ~s ln constant commun~cat~on with a vent-rel~ef passage 296 prov~ded
through the end of the outlet housing lY, and the other end of the bore 294
~s sultably secured, such as by ultrasonic welrls, to a valve seat member 298
havlng a central passaue 300 therethrough in constant co~ourlicatlon with the
motor chamber 28. rhe central passage 300 opens ~nto an oblong valve seat
301 ln the form of an oblong counterbnre having a width equal to the
diameter of the central passage 300 and a length twlce thereof. When 1n
c~ntact wlth the valve seat menber 298, the ball 292 can contact the oblong
valve
seat 301 e~ther at two diametrically oppos~-te points i~ centrally located
thereon~ or in a semi~circle 11ne cnntact i~ sh~fted to e~ther extreme s~de
thereof. E~ther way, there is a tlypass passage con~tantlv open between the
ball 292 and the oblong valve seat 301.
Also located ~n the valve chamber ~95 formed by the bore 294 and
the valve seat member 2~8 i~ a tuhular pop-o~f or rellef v31ve 302, a f1rst
hel1cal spr~ng 304~ a second hel~cal spr~ng 306, and an O-rlng 308~ One end
of the first helical spring 304 is biased against an annular shoulder 310
formed
~n the vent-rellef passage 29b, and the other end of the first helical
spring 304
~s biased against an annular top surface 312 formed at the top of the pop-
off valve 302 and enclrcl~ng a central vent ~assage 314 therethrough. The
first helical spring 304 biases the tubuL~r pcp-off valve 302 to normall~ seat
and
seal aga1nst the O-rlng 308, the O-rlng 308 belng normally seated on an
annular seat surface 316 provlded cn the vdlvc seat member 298 about the
oblon~ valve seat 301 thereo~. ~Ihen the ~op-ofF va1ve 302 ~s~thus~nor~dlly
urged aga~nst the O-r1ng 308 to seal agalnst the annuldr seat surface 316t a
normally-open bypass passage ~s estJbl-ished from the central passage 300 of
the valve seat member 298, through the central vent passage 314 of the pop-
-18-
of~ valve 3029 and the vent-rellef passage 29fi of the outlet housing 190
lh~s vent bypass passage~ clnse~ as ~/ill be ~escr~b~d ~/hen the pu~p
assembly 10 produces a fluid pressure in excess of a predeterm~ned maxlmum
venting pressure 1n the form of a llquid at the ball 2q2.
The tubular pop-off valve 302 a1so has an ~xternally slotted tubu-
lar portion 318 hav~ng a tube bore 320, at one end clearin~ the outer
diameter of the ball 2~2 and hav~n~ an annular hub seat 322 dependlng lnter-
nally from the ~ther end~ One en(J o~ the cecon~ helical spring 306 is
seated about the annular ilub seat ~,2, an~ the other end engages a
perlpheral surface of the ball 292 to nor~ally urge the ball 2~2 to seat on
the oblong valve seat 301. ~o~ever, when the flu1d pressllre experienced by
the pump lO cxceeds the maximum venting presslJre, such excess pressure over
comes the bias of the second helical spr~ng 306 orl the ball 292 and moves
the ball 292 towards the annular hllt seat 3~2, seating on th~ same when the
pump pressure exceeds the predetermined m~ximum ver1ting pressllre. At pump
pressures between the maximum vent~ng pressure and a predetermined rel1ef
pressure, the ball 2~2 closes the fluid passage hetween the central-s-eat_.
pass~ge 300 and the vent-relief passage 26.
To prov1de a rellef capah~llty or condition when the pump
experlences a flu1d pressur~ 1n excess of the predeterm~ned relief pressure,
the ax~al periphery 324 of the pop-off valve 302 is provided wlth slx ribs
32~a, 326b, 326c, 326d, 326e, and 326f, exterl~ln~ ra~idlly outwards and
~ 6D -ruB~
spaced equlan~ularly thereabout on the~be portion 31~, the r1bs 326a
through 326f also guld~ng and centrally pnsltinning the pop-off va1ve 302
wlth respect to the bore 294. Each of the axlal rlbs 326a through 3?6f ~s
cont1guous w1th a respect1ve spacer tab 32~a through 32~f upstand1ng ax1al1y
from and about the annular top surface 312 and the central vent passage 314
therethrough~ The tabs 328a -~rough 328f are adapted to abut against and
space the rem~1nder of the pop-off valve 302 ax~ally from an annular stop
-19-
sur~ace 330 counterbored In the outlet houslng 19 about the vent-
rellef passage 296. The rIbs 326a through 326f and the respec-
tlve tabs 328a through 328~ form passages or slots 332a through
332f therebetween spaced equlangularly about the axlal perlphery
324 of the pop-off valve 302. The slots 332a through 332f coop-
erate wlth the vent-relleF passage 296 to contlnually communlcate
the entlre space between the bore 294 and the axlal perlphery 32
of the pop-off valve 302 wlth the vent-rellef passage 296. How-
ever, thls space Is not communclated wlth the central passage 300
untll the pump experlences a fluld pressure In excess of the
rellef pressure, such excess pressure then overcomlng the seatlng
blas of the flrst hellcal sprlng 304 agalnst the 0-rlng 308 to
thereby move the pop-off valve 302 away from the annular seat
surface 316 and towards the annular stop surface 330. Such
excess pump pressure thereby urges the pop-off valve away from
the 0-rlng 308 to unseat from the annular seat surface 316
thereby openlng a passage from the central passage 300, between
the bore 294, the perlphery 324 of the pop-off Yalve 302, through
the slots 332a through 332f, and out through the vent-rellef pas-
sage 296.
Further alterna~e features of the pump 10, as shown InFlgures 10 and 10A are alternate tubular bushlngs 340 and 340a,
the axlal length of whlch has a convex form or ralsed portlon In
the shape of an outwardly extendlng bowl or crown 342 that con-
tacts a bore 344 In ~he outlet houslng 19 to allow a sllg~1t 0nd-
for-end self-alIgnment of the armature shaft 60. To restraln the
tubular bushlng from rotatlng In the bore 344, an antl-rotatlon
devlce Is provlded In the form of a slot and key arrangement 348
whereln a slot 348a In the tubular bushlng 340 Is clrcumferen-
tlally somewhat wlder and radlally somewhat deeper than a key
348b,
A further feature of the wet motor gerotor pUmP 10 Is
the utlllzatlon of otherwlse exlstlng structure In the alternate
outlet houslng 19 In comblnatlon wlth addltlonal passages formed
- 20 -
~lq~
thereln to cool and lubrlcate a portlon of a tubular bushlng 340
between the polnt of contact of the ralsed portlon 346 wlth a
bore 344 and the roof 860 of the outlet houslng. As may be bet-
ter understood wlth reference to the outlet houslng 19 shown In
Flgures 10 through 16, a bearlng lubrlcatlon and coolIng system
350 In -the form of a flow network 354 Is provlded between a
ralsed cap portlon 352, a cylIndrlcal perlpheral surface 89 of
the commutator 8~, the bore 344, and a palr of brush support
rldges 356 and 358 ~or supportlng the brushes 90 and 92, respec-
tIvely.
As best seen In Flgure 12, the ralsed cap portlon 352Includes the generally flat roof 360 supportlng the outlet valve
250 and the vent-rellef valve 290 hose fIttlng, and further
Includes a palr of slde walls 362 and 364, and a Palr of curved
end walls 366 and 368.
The flow network 354, when vlewed In the transverse radlal plane
of Flgure 13, Is shaped generally In the form o~ the Roman
numeral X. More partlcuiarly, the flow network 354 Includes four
branches 370, 372, 374 and 376, each In the shape of a dog leg
and each communlcatlng wlth the axlal length of the bore 344 as
well as an annular recess 378 enclrclIng a stop hub 380
proJectlng Into the bore 344 from the roof 360. Each of the
branches 370 through 376 extends axlally along the bore 344to the
Inner surface 361 of the roof 360. Eachlncludes a slde wall
branch portlon 370a, 372a, 374a and 376a. Each such slde wall
branch portlon Is generally parallel to one of the slde walls 362
and 364, wlth the slde wall branch portlons 370a and 372a gener-
ally spannlng the vent-rellef valve 290 whlle the slde wall
branch portlons 374a and 376a generally span the outle-t portlon
252. Each of the branches 370, 372, 374 and 376 also Include a
radlal branch portlon 370b, 372b, 374b and 376b, each termlnatlng
In a respectlve slde wall branch portlon wlth a respectlve radlal
- 21 -
slot 370c, 372c, 374c and 376c formed clrcumferentlally through a
bore wall 382 provldlng the bore 344.
The brush suPport rIdges 356 and 358 Include an arcuate
rldge
1 0
~ 21a -
crown or Yall ele~ent 35Ca and 3582 faclna t ~di~lly 1m~ar(l, the arcuate ~idgecrcwn 356a being bolmcled by a pair of radial rid~e side walls 356b and
356c while the arcuate r~ge crow~ wall 358a ~s bounded ~y a pa1r o~ radidl
ridge slde walls 35~h and 358c Each set of the radlal rldge slde ~alls
356b, 35~c, 358b, and 358c are spaced rad~ally apart by an included angle of
about ninety degrees (gO) ancl; to~ether ~Jith the1r respective arcuate rldge
cro~n ~alls 356a and 358a, extend dxially tc an arcuate ridge ~all counter-
bore 384 at a depth corresponding with the axlal ~vidth of the commutator 88.
The arcua-te ridge crowns or walls 356a and 358a are of a dia~e-ter slightly
greater than that of the commutator~ 88 to allow clearance therebetween for
approprlate brush co~mutator interaction. The bore 34q conmences at the
depth of the arcuate ridge counterbore 384 ~nd extends axially to the inner
stde 36I of the roof 360. With the bnre 344 starting belo~/ the brush sup-
port rldges ~56 and 358, there ~s an arcuate opening of approxi~ately nlnety
degrees (90) between the radlal ridge side walls of the opposing brush
support
rldges 356 and 358. In other words, there 1s a circumferent1al gap of about
ninety degrees ~9~) extending the axial lcngth of the commutator ~8 between
the radlal ridge side walls 356b and 358b and a si~ilar gap extends circum-
ferentially between the radlal r~dge slde walls 356c and 358c.
Assuming that the armature 8~ is ener~ized to rotate ln a coun-
terclockwlse dlrectlon as viewed in Fi~ure 13, the c~lindrical periphery
surfaoe 89
of the commutator 88 vlscollsly draqs Fluid therewlth, such ~luld belng
picked up by the rotation of the commlJtator at the radial slots 376c and 372c
hav1ng, respect~vely~ the radlal ridge side walls 356c and 358b and belng
delivered or thro~ln oFf against the next radial riclge side walls 358c and
356c~ respect1vely~ of the radial slots 374c and 370c. The fluid picked
up at the
diametrically oppos~ite radial rid~e side walls 35~c and 358~ therefore~
experiences a h19her veloc=ity thdn the fluid -impacting ~nd collecting at the
diametrically opposite radial rid~e side walls 356b and 358c. This
differenoe in
veloclt es causes the fluld ln the radial slots 370c and 374c to
r~ve slower and~therefore~be at a pressure h igher than the fluid at the
-22-
~ 37
radial slot port~ons 37LC and 376c. A sf~llar ~ressure ~ifferential could
be effected by other struc-tures~s-lcl- as a vane or otiler form of -flo~
res~stance, the ridge ~alls fn -the ~rosent e~ho(~=iment servlllg a dual func-
tion oF supporting the hrushes ~/hile also prcv~ding the necessary pressure
differentfal.
In any event, the resultfng pressure dlfferentlal created by the
,~ C ~ L - N D ~\ C A ~ q t 6,
drag forces of the ccmmutator\perlp~ery~89 on the flu-ld at the lndicated
radlal ridge s1de ~alls effects a pumplng actlon of fluid in the radial
branch portfons 370b and 374b. ~uch pumplng actfon is axially outwards
towards the inner surface 361 of the roof, then radially inwards lnto the
annular recess 378, then axlally about the tubular bushing 3~0, then
radially out-
wards from the annular recess 37~, an~ finally back through the opposlng
radial brancll portlons 372b and 37fih. In other words, the co~mutator
cylindrical peripheral surface 89, the brush supp~rt ridg~s 356 and
358 , and the flcw ne~w~rk 354
establlsh two parallel pumping chambers or circuits separated by the com-
mut~tor 88 but ~o1ned at the annular recess 378. The pressure dffferentials
created by the dlf~erence in velocit~es at the indlcated ra~tal r~dge side
~al1s provfdes two 1ncomlng and t~o outgo~n~ flo~/s of fluid thereatg both
flows cGmblnfng to cool an(l lubr~cnte the tuhular hushing 340 and the bore
344. Wlth such coolfng and lubrication, the life of the upper tubular
bushing 3~0
has been found to be slgn~ficantly fncreased over the life of the same
bearfng wlthout such luhrlcatlon and coollrg. MoreoYer, an acceptable
lubrlcatfon w~ll als~ occur by provldfng just a slngle circult com-
municat1ng ~Ath the annular recess 378 co~lunicatlng w~th the upper end por-
tion of the~tubular bush mg 340 above the point its crown 342 oontacts
the bore 344.
Such lubr~catlon would be less than that provlde~ by the dual parallel c1r-
cu~t shown. Also, a sl1ght fl~ of fluld mlght be prov~ed by such a s~ngle
circu~t should the lnternal structure by happenstance prov~de a sufficient
pressure differential between the ~nlet and the outlet to the annular recess
378, wlthout the benefit of addit~onal pressure bulld~ng structures.
23-
l~1though the bPst Ino~e conten-p7..lted by the Inven~or for carrylng
ou-t the present lnvent~nn as of the fllir(7 (late hereof has ~een shown as
descr7i~e~ herE7n9 it wi11 be apparent to those s~llled in the art that
su-itable modificatlons, vari~7t70ns, and e~ulvalents mdy be ma(Je ~lthout
departing from the scopc of the invention. Tilis invention is to be limited
so7ely by the tcrms oF the clair1s appen(led hcretc!.
-24-
