Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to a self contained
wet clutch assembly and is of ~he type adapted to be mounted
on a transmission input shaft.
Dissipation of heat from friction linings of clutch
plates has long been a problem during operation of the
clutch to engage or disengage the manual transmission from a
vehicle engine. Fluid has been introduced wi~hin the clutch
assembly to be forced between the friction linings and the
pressure plate and fl~wheel as a solution to the problem, but
this solution is complicated by the centrifugal force developed
on the fluid whil~ the clutch is rotating tending to sling the
fluid radially outwardly of the plates. Even where the fluid
has been successfulin the cooling of the friction linings, a
further problem o~ leakage of the cooling fluid from the clutch
assembly is encountered because most wet clutches are adapted to
the engine flywheel to make up the containment package. The
present invention effectively solves the leakage problem in
providing a truly self-contained wet clutch assembly.
According to ~he present invention there is provided
a sel~-contained wet clutch assembly adapted to be mounted
on a transmission input shaft, the assembl~ having a front cover
assembly, a rear cover assembly, a clutch plate assembly, and
a concentric ~lave cylinder assembly. The front cover assembly
includes a front co~er having an outer peripheral flange and
the rear cover assembly includes a rear cover having outer and
inner peripheral flanges extending in opposite directions. The
outer peripheral flanges of the front and rear covers conform
telescopically and are seal welded together. The clutch pla~e
assembly is loca-ted within the sealed front and rear covers and
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is operatively connected onto -the transmission shaft. The slave
cylinder assembly is rigidly moun-ted on a transmission housing
receiving the transmission input shaft, and includes a bearing
and an oil seal receiving the inner flange of the rear cover
to provide a completely sealed assembly.
In a specific embodiment of the invention there is
provided a plurality of circumferentially spaced inertia
weights which are mounted on the front cover ancl are adapted
to be secured on a radial flange of an engine ou-tput shaft
providing the driving torque for the assembly.
The present invention thus comprehends the provision
of a self-contained wet clutch assembly that mates the wet ~`
clutch driven member to a cover wherein the assembly is
suitably sealed together as a unit. The sealed assembly may be
mounted on and operatively connected to the engine crankshaft
through the series oE mounting bosses or inertia we.ights on the
cover secured to a drive plate mounted on the cran~shaft. This
arrangement eliminates the necessity o a fl~heel on the
crankshafi. Without the flywheel, the sealed unit obviates
2~ the oil leakage problem of prior wet clutches.
A specific embodiment of the present invention also
comprehends the provision of a self~contained sealed wet clutch
assembly having a release or throw-out bearing to engage the
spring fingers of the Belleville spring within the sealed
assembly, wherein the bearing carrier takes the form of a con-
centric hydraulic piston in a hydraulic cylinder mounted to
the transmission face~ The piston .in the cylinder is actuated ....
through a master cyllnder that is hydraulically connected thereto
and is actuated through the clutch pedal by the vehicle operator.
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A specific embodiment oE the present invention further
comprehends the provision of a ratarding brake adapted to engage
the driven shaft when the clutch assembly .is disenga~ed through
actuation of the release bearing carrier by the vehicle operator.
The retarding brake is of the radial type and is housed in
the stationary cylinder portion carrying the actuating piston
for the release bearing. The retarding brake comprises a
pair of diametrically opposed bra~ing elements that are normally
biased away from the driven shaft and, upon movement o~ the
piston and release beaxing to disengage the clutch, the braking
elements are cammed into engagemen~ with the shaft.
A specific embodiment of the present inven~ion may also
comprehend the provision of turbulizer vanes on the interior
surface of the clutch housing to .increase oil splash and enhance
movement of the oil between the clutch plate and the pressure
plate and housing for cooling of the elements. The increase of
oil splash also reacts with protruding diverters on the
. periphery of the clutch plate and retards the clutch plate or
driven member.
20 The present invention further comprehends the provision
of a self-contained wet clutch that is adaptable to a single
clutch plate or a multi-plate clutch construction.
Further objects are to provide a construction oE
maximum simplicity, efficiency, economy and ease of
assembly and operation, and such further objects,
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advantages and capabilities as will later more ully
appear and are inherently possessed thereby.
One way of carrying out the invention is described
in det~l below with reference to drawings which illustrate
only one specific embodiment, in wh:ich:-
Figure 1 is a vertical cross sectional view througha self-contained wet clutch of the ~resent invention with
a master cylinder and clutch pedal being shown diagram-
matically.
Figure 2 is an enlarged vertical cross sectional
view through the release bearing9 carrier and actuating
piston with the clutch in disengaged position.
Figure 3 is a vertical cross sectional view taken on
the line 3-3 of Figure 1.
Figure 4 is a vertical cross sectional view taken on
the line 4-4 of Figure 1.
Figure 5 is a vertical cross sectional view taken on
the line 5-5 of Figure 1.
Figure 6 is a partial vertical cross sectional view
similar to Figure l but._sh"o,wing a.m,ulti-plate clutch
assembly.
Referring more particularly to the disclosure in the
drawings wherein are shown illustrative embodiments of
the present invention, Figure l discloses a self-contained
clutch assembly 10 that is suitably sealed and eliminates
the necessity for a flywheel as is conventionally found
mounted on an engine crankshaf~ ll. A drive plate 12 is
substituted for the flywheel and is secured to the crank-
shaft by bolts 13. The drive plate has an outer peri-
pheral flange 14 with a starter gear 15 suitably securedthereto, such as by welding. A bell housing 16 encompasses
the clutch assembly 10 and is adapted to be secured to
the engine or the vehicle and to the transmission
housing.
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The clutch assembly 10 includes a rear cover assembly
A and a front cover assembly B. The rear cover assembly
A comprises a rear cover 17 having an outer for~ardly
extending annular flange 18 and an inner rearwardly
extending annular flange 19 defining a central opening 21
for a transmission input shat 22. .A plurality of rivets
23 are secured in the cover 17 to support a Belleville or
diaphragm type spring 24 and annular fulcrum wires 25,
25, with an annular ring 26 s~.cured to the inner ends of
the rivets 23. A pressure plate 27 has a rearwardly
extending annular fulcrum surface 28 engaging the spring
24 and a plurality of radial lugs 29. A plurality of
drive straps 31 are secured at their ends to the lugs 29
and at their opposite ends to the cover 17 by rivets 32
so as to provide a driving connection between the pressure
plate 27 and the cover 17. The drive straps 31 are also
deformed 90 as to act as retractor springs for the
pressure plate when the clutch is disengaged. A blower
33 is spot welded to the exterior surface of the cover 17
for cooling purposes, and a fluid fill plug 34 is located
in the cover 17.
The front cover assembly B includes a front cover 35
having an outer rearwardly extending annular flange 36
and an inner pilot bushing 37 for pilo~ing the inner end
of the transmission input shaft 22. A plurality of
: segmental inertia weights 38 (Figures 1 and 5) are welded
to the cover 35 and are provided with threaded openings
39.to receive bolts 41 securing the drive plate 12 to the
front cover assembly B. Turbulizer vanes 42 are secured,
as by spot welding, to the interior surface of the flange
36 to aid in fluid distribution. The rear cover assembly
~ A and the front cover assembly B are mated together with
: the flanges 18 and 36 nested and seal welded at 43 to
form a completely self-contained unit to contain the
cooling fluid.
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Housed in the sealed cover assembly is a driven
member assembly C comprising an internally splined hub 44
receiving an exteriorly splined port:ion 45 of the shaft
22, the hub having an integral radial 1ange 46. A
clutch plate 47 and a spring retainer plate 48 sandwich
the flange 46 and are secured together by shouldered
rivets 49 and piloted on the hub by eompression sprlngs
51 received in pockets defined by al:igned openings in the
flange 46 and plates 47 and 48. The flange 46 has
circumferentially spaced notches 52 receiving the rivets
49 to limit the relative rotation between the flange and
the plates allowed by the compression springs. The
clutch plate 47 has oppositely disposed friction material
surfaces 53, 53 positioned adjacent the outer periphery
of the plate so as to engage an annular friction surface
54 ormed in the cover 35 and the friction surface 55 of
the pressure plate 27.
A slave cylinder assembly D is provided at the rear
end of the clutch assembly and includes a hollow ram-type
cylinder housing 56 having a radial flange 57 at the rear
end secured by bolts 58 to the bell housing 16. The
housing provide~ a central passage 59 receiving the
transmission input shaft 22 and an annular chamber 60
receiving a reciprocable bearing carrier 61 with a clutch
throw-out bearing 62 press-mounted on the fo~ard end and
~ an enlarged piston 63 forming the rear end of the carrier.
A lip-type seal 64 is provided in an annular groove 65 on
the exterior surface of the piston, and an 0-ring type
seal 66 is provided in an annular groove 67 on the
internal diameter of the piston, with the seals slidingly
engaging the chamber walls. Also, a snap ring 68 is
provided in an annular groove 69 in the wall of the
chamber 60 to limit ~he forward travel of the piston; the
piston having an annular flange 71 at its rear end adapted
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to abut ~he rear end of the chamber to limit rearward
travel and provide a substantial area of the piston face
72 exposed to actuating hydraulic fluid.
The cylinder housing includes an outer wall 73
counterbored at 74 to receive a bearing 75, such as a
bronze bushing, and having an enlarged counterbore 76 to
receive an oil seal 77 pressed thereinto. The inner
flange 19 of the rPar cover 17 is sealingly received
within the oil seal 77 and rotatably received in the
bearing 75 so that the rear covPr assembly A, front cover
assembly B and driven member assembly C can rotate
relative to the stationary slave cylinder assembly D. A
hydraulic fitting 78 is positioned in the housing 56 to
communicate with the rear end of the chamber 60 and to
connect the chamber with a master cylinder 79 removed
from the clutch assembly.
A transmission input shaft retarder 81 is provided
in the housing passage 59 to retard or brake rotation of
the transmission input shaft 22 when the clutch is
; 20 disengaged. The retarder comprises a pair of arcuate
metallic shoes 82, 82 on diametrically opposite sides of
the shaft 22 with bonded friction linings 83, 83 on the
inner curved suraces of the shoes facing the shaft.
Each shoe has a central projection 84 rec2ived in a slot
85 in the inner wall 86 of the housing 56 with a curved ~-
upper surface 87 extending into the chamber 60. A central
groove 88 in each shoe receives a spring clip 89 to hold
the shoes in place and act as a retractor spring at the
time of clutch re-engagement. The interior wall of the
bearing carrier 61 is provided with an annular groove 90
receiving the curved end surfaces 87, 87 of the projections
84, 84; the rear end of the groove being provided with a
c~mming ramp ~1 acting to urge the shoes 82, 82 inwardly
to contac~ the shaft 22 as will be later described.
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077080-BB 7
The master c~linder 79 comprises a housing 92 for a
reciprocable piston 93 having a seal 94, and a push rod
95 secured to the piston and extending from the cylinder
to be pivo~ally mounted at the free end on a push-type
pedal 96 to be actuated by the vehicle operator. The
cylinder 79, ccnnecting conduit 97 and chamber 60 behind
the piston 63 are filled with hydrau,lic fluid; the
cylinder housing 56 having a bleeder valve 98 acting to
purge the hydraulic system of entrapped air.
As more clearly seen in Figure 4, ~he clutch plate
47 is provided with several diagonally extending slots 99
partially dividing the plate into a plurality of circum-
ferentially spaced segments 101, the slots 99 extending
from the outer periphery 102 of the plate to an inner
peripheral portion thereof. Associated with the slots
are fluid diverters or scoops 103 at the outer edge of
each segment 101; each diverter being integral with the
plate and having an outer peripheral edge 104 with the
forward or leading portion formed as a finger lOS in
overlapping relation to the slot 99 immediately ahead of
the segment. The inner edge 106 of the finger is a
curved fluid scooping surface generally parallel with the
curved edge 107 of the adjacent trailing portion of the
segment thereahead. At the trailing edge of each scoop
103 is a pocket 108 defined by a rearwardl~ and slightly
outwardly extending finger 109 having a concave edge llI
joining the ~inger to the plate periphery.
It should be understood that the terms "leading" and
"trailing" used with reference ~o the fluid diverters refer
to the direction of relative rotation between the cover
assembly A and B and the driven clutch plate 47. The
clutch plate 47 is rotating in the same direction as the
cover assembly, however, until full clutch engagement, the
plate 47 rotates slower than the cover assembly; thus
having a direction of reIative rotation opposite to the
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arrow X of Figure 4. The friction pads 53 on ~he clutch
plate segments 101 each has a waf1e grid formed thereon by
intersecting grooves 112 and 113.
With the vehicle engine running, the clutch assembly
10 is normally engaged ~hrough the load imparted by the
Belleville spring 24 against -the fulcrum surface 28 of the
pressure plate 27 to urge the pressure plate against the
clutch plate 47 and the friction surface 5h of the front
cover 35 so that the driven member assembly C rotates with
the sealed rear cover assembly A and front ccver assembly B
to rotate the transmission input shaft 22. The positioning
of the parts of the clutch assembly with the clutch engaged
is shown in Figure l. The inner ends of the spring fingers
114 of the spring 24 are in constant engagement with the
clutch throw-out bearing 62.
To release the driven member C from the pressure plate
27 and the front cover 35 for the purpose of shifting
gears, the operator depresses the clutch pedal 96 to force
fluid from the cylinder 79 by means of the piston 93 into
the annular chamber 60 behind the piston 63, thus imparting
hydraulic force against the piston face 72 to shif~ the
bearing carrier 61 forwardly to the position shown in
Figure 2. The throw-out bearing 62 moves against the
fingers 114 of the Bellevil~e spring 24 to unload the
pressurP plate 27, with the drive straps 31 acting to
retract the pressure plate.
At the same time, the camming ræmp 91 is moved relative
to the retarder 81 and engage the curved surfaces 87, 87 to
urge the shoes 82, 82 and riction linings 83, 83 radially
inward against the force of the spring 89 to engage the
rotating shaft 22. The engagement between the shoes and ^
the shaft acts to retard rotation thereof and, as -the
housing assembly A and B is decreasing in rotation due to
the closed throttle of the engine, the fluid tends to
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077080-BB - 9 -
continue at a high velocity due to its inertia, thus
impinging on the turbulizer vanes 42 and forcing the fluid
into the path of the fingers 109 of the diverters 103 (as
seen in Figure 4) to aid in retardat:ion of the clutch plate
47 and driven member assembly C. The fluid acting on the
vanes 42 and the diverters 103 aids :in heat dissipation and
lubrication of the clutch wi~h a portion of the fluid being
forced ~hrough the slots 99 and the Lining grooves 112, 113
toward the center of the unit.
Another purpose of the turbulizer vanes 42 is to act
as a reserve means of diverting fluid onto the driven
member 47 in the event that the dynamic oil level falls
below the required level, thereby rendering the driven
member diverters 103 inopera~ive.
Once the gears are shifted, the operator gradually
releases the pedal 96 and the spring 24 through the fingers
114 acts to urge the bearing 62 and bearing carrier 61
rearwardly to force the fluid back into the cylinder 79.
Initial movement of the carrier 61 releases the shaft
retarder shoes 82, 82 from the camming ramp 91 for re-
traction by the spring 89, and the spring 24 fulcrums about
the wire 25 to urge the pressure plate 27 against the
clutch plate 47 and the front cover 35. As the ~riction
surfaces begin to engage and the throttle causes rotation
of the cover assembly A and B, the fluid is moved in the
cover assembly ~aster than rotation of the clutch plate and
a portion of the fluid is scooped up by the diverters 103
to ente~ the slots 99 and travel toward the center of the
unit and then urged outward through the grooves 112, 113 by
centrifugal force to cool and lubricate the assembly. When
the clutch is fully engaged, the scooping o~ the fluid
ceases as there is no relative rotation be-tween the cover
assembly A and B and the clu~ch driven assembly C.
Figure 6 discloses an alternate embodiment of self-
contained wet clutch utilizing a multi-plate driven mem~er,
and parts identical to those o~ the previously described
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assembly will have the same reference numeral with a script
a. In this embodiment, the clutch assembly lOa includes a
rear cover 17a with an outer flange 18a and an inner flange
19a, shouldered rivets 23a supporting the fulcrum wires 25a
and support ring 26a for the Belleville spring 24a, and the
blower 33a secured to the outer rear surface of the cover.
A front cover 35a has an outer flang~e 36a telescopingly
receiving the flange 18a, segmental inertia weights 38a
welded to the cover 35a and an inner pilot bushing 37a
receiving the inner end of the transmission input shaft
22a. A drive plate 12a secured to the engine crankshaft
(not shown~ is secured to the segmental weights 38a by
bolts 41a. The ~langes 18a and 36a are seal welded at 43a.
The driven member assembly includes a pair of clutch
members 115 and 116, each clutch member having a hub 44a on
the splined portion 45a of the transmission input shaft 22a
with an integral radial ~lange 46a. Each hub flange is
sandwiched between a clutch plate 47a, 117 and spring
retainer plates 48a, 48a, and compression springs 51a are
received in aligned windows for a vibration damper. Each
clutch plate has clutch friction pads 53a similar to those
shown in Figure 4. The clutch plate 47a is adapted to
engage the fxiction surface 54a of the front cover 35a
while the clutch plate 117 has an offset ll8 so as to
contact the friction surface 55a of the pressure plate 27a.
~ An intermediate pressure plate 119 is interposed between
the clutch plates 47a, 117 to frictionally engage the
friction pads~53a of each; the intermediate plate being
connected to the pressure plate 27a by drive straps 121
secured to each member by rivets 122.
The concentric hydraulic slave cylinder includes a
housing 56a or a bearing carrier 61a in a chamber 60a
supporting a clutch ~hrow-out bearing 62a. Shaf~ retarder
shoes 82a are mounted in the housing to cooperate with the
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077080-BB
camming ramp 91a to engage the input shaft 22a when the
clutch is disengaged. A bushing 75a and an oil seal 77a
are pressed in the housing 56a to rotatably support the
inner flange l9a of the rotating cover assembly. This
clutch arrangement operates in substantially the same
manner as previously described for the embodiment of
Figures 1 through 5.
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