GB2351331A

GB2351331A - A clutch assembly

Info

Publication number: GB2351331A
Application number: GB0023573A
Authority: GB
Inventors: Gordon Maurice Sommer
Original assignee: Midwest Brake Bond Co
Current assignee: Midwest Brake Bond Co
Priority date: 1996-06-27
Filing date: 1997-06-17
Publication date: 2000-12-27
Anticipated expiration: 2017-06-17
Also published as: GB2351331B; GB0023573D0

Abstract

A clutch assembly 214 comprises a clutch housing 306, a clutch hub 300, rotatably disposed with respect to the housing 306 and a clutch disposed between the clutch hub 300 and the clutch housing 306. The clutch is movable between an engaged and disengaged position. In the engaged position the clutch hub 300 is locked to the clutch housing 306. In the disengaged position the clutch housing 306 can rotate relative to the clutch hub 300. The clutch comprises a plurality of circular friction plates 302 alternately splined, respectively, to the clutch hub 300 and the clutch housing 306. A lubricant flow path (illustrated by arrows 369) extends through the clutch assembly for flow therethrough of lubricating oil in a direction from the clutch housing radially inward between two of the plurality of circular friction plates 302 to the clutch hub 300.

Description

23,51331 A CLUTCH ASSEMBLY This invention relates to clutch assemblies.

Dry friction clutch/brakes depend upon the rubbing of a dry friction material against dry reaction members to start and stop a press. This continuous dry rubbing causes wearing of both the friction material and the reaction members as well as causing the generation of heat in these members. The faster the press operates and the faster the flywheel rotates, greater is the amount of wear and heat which are generated. This generation of wear and heat requires periodic gap adjustment between the friction plates and the reaction members to keep the clutch/brakes functioning and the press operating correctly. The trip rate or cycle speed of a press equipped with a dry friction clutch/brake unit is limited because the mass of the unit determines its heat dissipation capacity. If the mass of the unit is increased to increase its heat dissipation capacity, the inertia that must be started and stopped is also increased. These factors define a closed loop from which it is impossible to escape when trying to substantially increase the performance of the system.

Oil shear brake and clutch units have been developed to eliminate the problems associated with the dry friction type of units. The oil shear systems use hydraulic actuation instead of air actuation and the units have been developed with key modules which can be easily adapted to be mated with the various types of presses. Properly designed oil. shear clutch/brake drives offer the advantage of little or no wear of plates in the disk stacks and no brake fade. This provides a more precise operation of the press and dramatically increases press up-time. The oil film between the adjacent disks carries the heat generated by the start-stops of the unit away from the disk stacks. This removal of heat offers the advantage that there is now no practical limit for the press trip rate and the flywheel speed. In addition, this removal of heat provides unlimited inching capabilities.

While these oil shear clutch/brake drive units have significantly improved the operation of the units, they have all been supplied as single units which have the clutch and brake units interfaced using various techniques for the engagement and disengagement of the clutch and for the application and release of the brake. One problem associated with these prior art oil shear clutch/brake drives has been the coordination between the operation of the brake unit and the operation of the clutch unit. Accordingly, what is needed is a press drive system which incorporates the flexibility to be applied to a wider variety, of presses where size and performance are of the utmost importance. In addition, the press drive system should simplify the coordination and operation of the brake and clutch units. According to a first aspect of the present invention there is provided a clutch/brake drive comprising: a brake housing., a brake hub rotatably disposed with respect to said brake housing; a clutch housing rotatably disposed with respect to said brake housing, a clutch hub rotatably disposed with respect to said clutch housing., a brake disposed between said brake housing and said brake hub, said brake being movable between an applied condition where said brake hub is locked to said brake housing and a released condition where said brake hub can rotate with respect to said brake housing, said brake comprising a first plurality of circular friction plates alternately splined, respectively, to said brake housing and said brake hub; a clutch disposed between said clutch hub and said clutch housing, said clutch being moveable between an engaged condition where said clutch/hub is locked to said clutch housing and a disengaged condition where said clutch housing can rotate relative to said clutch hub. said clutch comprising a second plurality of circular friction plates alternately splined, respectively, to said clutch hub and said clutch housing,lubricating oil disposed within said clutch/brake drive; and a lubricant flow path extending through said clutch/brake drive, said lubricating oil flowing through said lubricant flow path in a direction from said clutch housing radially inward between two of said second plurality of circular friction plates to said clutch hub.

According to a further aspect of the present Invention there is provided a clutch assembly comprising:

a clutch housing-, a clutch hub rotatably disposed with respect to said clutch housing; a clutch disposed between said clutch hub and said clutch housing, said clutch being movable between an engaged condition where said clutch hub is locked to id clutch housing and a disengaged condition where said clutch housing can rotate sai n relative to said clutch hub, said clutch comprising a plurality of circular friction plates alternately splined, respectively, to said clutch hub and said clutch housing; lubricating oil disposed within said clutch assembly; and a lubricant flow path extending through said clutch assembly, said lubricating oil flowing through said lubricant flow path in a direction from said clutch housing radially inward between two of said plurality of circular friction plates to said clutch hub.

An embodiment of apparatus in accordance with the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure I is a side view, partially in cross-section, of a brake and clutch unit in accordance with an embodiment of the present invention-, Figure 2 is an exploded view, partially in cross section of the first installation step for the brake and clutch unit shown in Figure 1, Figure 3 is an exploded view, partially in cross section of the second installation step for the brake and clutch unit shown in Figure I Figure 4 is an exploded view, partially in cross section of the third installation step for the brake and clutch unit shown in Figure 1; and Figure 5 is an exploded view, partially in cross section of the final installation step for the brake and clutch unit shown in Figure 1.

Referring to Figure 1, there is shown an embodiment of brake and clutch unit in accordance with the present invention, which is designated generally by the reference numeral 210.

Referring now to Figure 2, the brake and clutch unit 2 10 includes a separate brake assembly 212 and a clutch assembly 214. Brake assembly 212 includes a brake reaction hub 220, a plurality of brake friction plates 222, a plurality of brake reaction plates 224 and a brake housing assembly 226. Brake reaction hub 220 is drivingly connected to drive shaft 30 of the press to which clutch/brake apparatus 210 is being attached. Brake assembly 212 defines an internal oil tight chamber within housing assembly 226 to provide lubrication for the various components of brake assembly 212 as well as for supplying cooling oil for oil shear brake assembly 12.

The plurality of brake friction plates 222 have spline means 240 located on their interior surface for engagement with spline means 242 disposed on the exterior of hub 220. This spline engagement between plates 222 and hub 220 is such that plates 222 and hub 220 will rotate together but plates 222 are allowed to move axially along spline means 242. Interjected or interleaved between the plurality of brake friction plates 222 are the plurality of brake reaction plates 224. Brake reaction plates 224 have spline means 244 located on their exterior surface for the engagement with spline means 246 disposed on the interior of housing assembly 226. The engagement between plates 224 and housing assembly 226 is such that plates 224 are prohibited from rotating with respect to housing assembly 226 but plates 224 are allowed to move axially along spline means 246 of housing assembly 226. Housing assembly 226 in conjunction with brake reaction hub 220 defines a sealed chamber 23 8. Housing assembly 226 includes a brake ring adapter plate 250, a brake reaction member 252 and an actuator assembly 254.

Adapter plate 250 is fixedly secured to the frame or a stationary member 57 of the press or any other non-moving member adjacent to the press. A seal 259 located between adapter plate 250 and brake reaction hub 220 maintains the oil tightness of chamber 23 8.

Brake reaction member 252 is fixedly and sealingly secured to adapter plate 250 with a plurality of bolts 260 or by other means known well in the art. A seal 262 between plate 250 and reaction member 252 maintains the oil tightness of chamber 238.

Reaction member 252 includes spline means 246, and positions spline means 246 generally co-axial with spline means 242 such that plates 224 and plates 222 are positioned in their interleaved relationship. Actuator assembly 254 is fixedly and sealingly secured to reaction member 252 using a plurality of bolts 264 or by other means known well in the art. A seal 266 between actuator assembly 254 and reaction member 252 maintains the oil tightness of chamber 238. A plurality of spacers 267 are located between actuator assembly 254 and reaction member 252 to properly position actuator assembly 254 with respect to plate 250, plates 222 and plates 224. A fluid passage 272 extends through actuator assembly 254 to provide for the application and release of brake assembly 212 as will be described later herein.

Actuator assembly 254 includes a brake housing 271 and a brake engagement assembly 273. Brake engagement assembly 273 comprises an application member 274 and an annular stationary plate 276. Application member 274 is slidingly received over brake housing 271 and moves axially along housing 271 In order to apply or release brake assembly 212. A seal 278 is disposed between housing 271 and application member 274 in order to isolate an activation chamber 280 from chamber 238. Stationary plate 276 is disposed between housing 271 and application member 274, and with member 274 and housing 271 define chamber 280. Stationary plate 276 is fixedly secured to housing 271 using a plurality of bolts 282 and a plurality of retainers 284. A seal 286 is disposed between plate 276 and housing 271 to isolate chamber 280 from chamber 238. A second seal 288 is disposed between plate 276 and application member 274 to complete the isolation of chamber 280 from chamber 238. Chamber 280 is isolated from chamber 238 with the only access to chamber 280 being through passage 272. A plurality of coil springs 290 are disposed within a plurality of bores 292 extending into application member 274. Springs 290 extend between housing 271 and application member 274 in order to urge brake assembly 212 into the applied condition.

The operation of brake assembly 212 begins with brake assembly 212 being in the applied condition due to the biasing of application member 274 by the plurality of coil springs 190. Application member 274 compresses the plurality of friction plates 222 and the plurality of reaction plates 224 together and against adapter plate 250. In this applied condition, rotation of drive shaft 30 is prohibited by the fact that brake reaction hub 220, which is locked to drive shaft 30, is locked to adapter plate 250 which is in turn secured to stationary member 57. When it is desired to release brake assembly 212, fluid under pressure is supplied to chamber 280 through passage 272. Pressurized fluid within chamber 280 causes application member 274 to move axially to the left as shown in Figure I against the biasing of coil springs 290. When application member 274 moves to the left, the compression between the plurality of friction and reaction plates 222 and 224, respectively, is released and plates 222 are free to rotate relative to plates 224 which allows drive shaft 30 to rotate. When the pressurized fluid is released from chamber 280, brake assembly 212 is again urged into its applied condition due to the biasing of coil springs 290.

Clutch assembly 214 includes a clutch reaction hub 300, a plurality of clutch friction plates 302, a plurality of clutch reaction plates 304 and a clutch housing assembly 306. Clutch reaction hub 300 is drivingly connected to drive shaft 30 of the Z> press to which clutch/brake apparatus 210 is being attached.

The plurality of clutch friction plates 302 have spline means 320 located on their interior surface for the engagement with spline means 322 located on the exterior surface of hub 300. This spline en agement between plates 302 and hub '300 is such that plates 9 11 302 and hub 300 will rotate together but plates 301 are allowed to move axially along spline means 322. Interjected or interleaved between the plurality of clutch friction plates 302 are the plurality of clutch reaction plates 304. Clutch reaction plates 304 have spline means 324 located on their exterior surface for the engagement with spline means 326 disposed on the interior of housing assembly 306. The engagement between plates 304 and housing assembly 306 is such that plates 304 are prohibited from rotating with respect to housing assembly 306 but plates 304 are allowed to move axially along spline means 326 of housing assembly 306.

Housing assembly 306 in conjunction with reaction hub 300 defines a sealed chamber 328. Housing assembly 306 includes a flywheel adapter plate 330, a clutch drive ring 332 and an actuator assembly 3-34. Adapter plate 330 is fixedly secured to a flywheel 138 of the press to which brake/clutch assembly 210 is being attached. A seal 33339 located between adapter plate 330 and clutch reaction hub 300 maintains the oil tightness of chamber 328.

Clutch drive ring 332 is fixedly and sealingly secured to adapter plate 330 by a plurality of bolts 340 or by other means known well in the art. A seal 342 between plate 3 330 and drive ring 332 maintains the oil tightness of chamber 328. Drive ring 332 includes spline means 326, and positions spline means 326 generally co- axial with spline means 322 such that plates 304 and plates 302 are positioned in their interleaved relationship. Actuator assembly 334 is fixedly and sealingly secured to drive ring 332 using a plurality of bolts 344 or by other means known well in the art. A seal 346 between actuator assembly 334 and drive ring 332 maintains the oil tightness of chamber 328. A plurality of spacers 347 are located between actuator assembly 334 and drive ring 332 to properly position actuator assembly 334 with respect to plate 330, plates 302 and plates 304. Actuator assembly 334 includes an internal housing 348, an external housing 3349, a housing cap assembly 350 and a clutch engagement assembly 35 1.

Housing cap assembly -3) 50 is rotatably supported by internal housing 348 and comprises a center hub 3 52 for interfacing with internal housing 348 and a protective cover 353. Center hub 352 is rotatably supported on internal housing 348 and external housing 349.by a pair of bearings 354. A seal 356 maintains the oil tightness of chamber 328. An inlet port 358 and an outlet port 359 extend through center hub 352 to provide for the attachment of fluid lines 360 and 361, respectively, which allow for the entrance and exit of oil for oil shear clutch assembly 214. Protective cover 253 is fixedly secured to center hub 352 by a plurality of bolts 362 or by other means known well in the art.

Cover 353 provides for the connection of a fluid line 364 for the engagement and release of clutch assembly 214 as will be described later herein. A seal 366 located between -8 cover 353 and center hub 352, and a seal 368 located between cover 35, and internal housing 348 maintain the oil tightness of chamber 328.

The oil flow for clutch assembly 214 is illustrated by arrows 369. Oil enters chamber 328 through fluid line 360 and inlet port 358 and this oil is directed to the outside portion of chamber 328 by an oil passage 371. The oil proceeds through plates 3 302 and 304 to provide the oil for the oil shear operation of clutch assembly 214 and the removal of heat from plates 302 and 304. The oil continues to the inside portion of chamber 328 to an oil passage 373 which mates with outlet port 359 and the oil is removed from clutch assembly 214 by fluid line 361.

The direction of the oil flow for the present invention is opposite to the direction of fluid flow normally utilized in the prior art. Prior art lubrication systems supply oil to the inside portion of the clutch and subsequently remove the oil from the outside portion of the clutch. The rotation of the clutch and the associated centrifugal force for the oil which is produced in the prior art clutches is in the direction of flow of the oil. Thus, there is a tendency in the prior art to increase the flow rate of the oil. Thus, should there be a momentary delay in the supply of oil to the inside portion of the prior art clutch, the friction plates which are located on the outside portion of the clutch would be momentarily starved of oil. This oil starving will result in the generation of heat and excessive wear between the plates.

The present invention by reversing the direction for the flow of the oil resolves prior art problems associated with momentary delay in the supply of oil, producing an unexpected increase in the performance of clutch assembly 214. The centrifugal force created by the rotation of clutch assembly 214 will impede the oil flow of the present invention because oil is fed to the outside of chamber 328 and oil is removed from the inside of chamber 328. The supply of oil to the outside of chamber 328 in combination with the centrifugal force produced by the rotation of clutch assembly 214 will tend to keep the oil in the outside portion of chamber 328 in contact with plates 302 and 304.

Thus, any momentary delay in the supply in oil will not starve clutch assembly 214 and plates 302 and 304 will remain bathed in oil. In addition, any "hot spots" which may be created between adjacent plates 302 and 304 will increase the temperature of the oil in that localized area making this higher temperature oil lighter and thus less affected by centrifugal force. This lighter oil will tend to migrate to the inside of chamber 3-18. The cooler, heavier oil will be forced by centrifugal force to the outside of chamber 328 and into contact with plates 302 and 304 increasing the cooling rate for the developed "hot spot. ', Clutch engagement assembly 351 is disposed within sealed chamber 328 defined by housing assembly 306 and clutch reaction hub 300. Clutch engagement assembly 351 comprises an application member 370 and a plurality of coil springs 372.

Application member 370 is slidingly received over internal housing 348 and moves axially along internal housing 348 in order to engage and release clutch assembly 214.

A seal 374 is disposed between internal housing 348 and application member 370 in order to isolate an activation chamber 376 from chamber 328. Application member 370 with external housing 349 and intemal housing 348 define a chamber 3 76. Chamber 3 76 is isolated from chamber 328 with the only access to chamber 376 being through a passage 3)86 extending through internal housing 348 to connect chamber 376 with fluid line 364 which extends through cover 353. The plurality of coil springs 372 are disposed within a plurality of bores 390 extending into application member 370.

Springs 388 extend between internal housing 348 and application member 370 in order to urge clutch assembly 214 into a disengaged condition.

The operation of clutch assembly 214 begins with clutch assembly 214 being in the disengaged condition due to the biasing of application member 370 by, the plurality of coil springs 388 to cause application 370 to move away from friction plates 302 and reaction plates 304. In this released position, flywheel 138 is free to rotate with respect to drive shaft 30 due to the fact that the plurality of friction plates 302 are free to rotate relative to the plurality of reaction plates 304. When it is desired to power drive shaft 30 by flywheel 138, fluid under pressure is supplied to chamber 376 through passage 386.

Pressurized fluid within chamber 376 causes application member 370 to move axially to the left as shown in Figure 1 against the biasing of coil springs 388. When application member 370 moves to the left, the plurality of friction plates 3)02 are urged against the plurality of reaction plates 304 causing engagement of clutch assembly 214 and the transferTing of power from flywheel 13 8 to drive drive shaft 3 0. When the pressurized fluid is released from chamber 376, clutch assembly 214 is again urged into its disengaged condition due to the biasing of coil springs 398.

Brake assembly 212 operates to stop drive shaft 30 from rotating with respect to flywheel 138 and clutch assembly 214 operates to cause drive shaft 30 to be rotated by flywheel 138. Because these operations are opposite to each other, it is necessary to coordinate the application and release of brake assembly 212 with the engagement and disengagement of clutch assembly 214 to insure that there is no overlap between the two assemblies. Operation of brake assembly 212 and clutch assembly 214 can be coordinated by designing the two assemblies 212 and 214 such that the coordination of their operation is designed into the assemblies. In one embodiment, the plurality of coil springs 290 and the plurality of coil springs 388 are designed to be generally identical in strength and number. Thus the urging force that applies brake assembly 212 and the urp-ina force that disengages clutch assembly 214 is generally identical. In addition, the size and dimensions of chamber 280 are generally identical to the size and dimensions of chamber 376. Thus when the same pressurized fluid is supplied to both chambers 280 and 376 simultaneously, brake assembly 212 will release simultaneously to the engagement of clutch assembly 214. In a similar manner, the disengagement of clutch assembly 214 and the application of brake assembly 212 will also occur simultaneously with the simultaneous release of pressurized fluid from chambers 280 and 376 and the reaction caused by springs 290 and 388. This eliminates the overlap between brake assembly 212 and clutch assembly 214 without the need for mechanically interlocking the two assemblies.

In another embodiment, the plurality of coil springs 290 and the plurality of coil springs 389 are designed to be different in number and/or different in strength. Thus the urging force that applies brake assembly 212 and the urging force that disengages clutch assembly 214 will be different. In order to maintain the commonization of components, -li- the size and dimensions of chamber 280 are left generally, identical to the size and dimensions of chamber 376 although this is not a requirement. Thus when the same pressurized fluid is supplied to both chambers 280 and 376 simultaneously, brake assembly 212 will release either prior to or after the engagement of clutch assembly 214.

Normally, the release of brake assembly 212 is designed to be after the engagement of clutch assembly 214 to provide a specified amount of overlap between the two assemblies. In a similar manner, the disengagement of clutch assembly 214 and the application of brake assembly 212 will not occur simultaneously with the simultaneous release of pressurized fluid from chambers 280 and 3) 76 and the reaction caused by springs 290 and 388. Normally, the application of brake assembly 212 is designed to be before the disengagement of clutch assembly 214 to again provide a specific amount of over lap between the two assemblies, Thus, a specified amount of overlap can be designed into the assemblies without the need of mechanically interlocking the two assemblies.

As shown in Figures 2 through 5, the design of brake and clutch unit 2 10 allows for the communication of components between presses. This leads to the simplification of manufacture and assembly as well as the reduction in costs of the units. The only components which have to be designed for a specific press are adapter plates 250 and 330; brake reaction hub 220 and clutch reaction hub 300. The remaining components.

including brake friction plates 222, brake reaction plates 224, brake reaction member 252, brake actuator assembly 254, clutch friction plates 302, clutch reaction plates 304, clutch drive ring 332 and clutch actuator assembly 34, are identical for all similarly sized presses.

The assembly of brake and clutch unit 2 10 to the press begins by first attaching brake adaptor plate 250 to stationary member 57 such as the brake ring of the press and clutch adapter plate 330 to flywheel 138 of the press as shown in Figure 2. These two components are designed for a specific press. Next, brake reaction hub 220 and clutch reaction hub 300 are attached to drive shaft 30 as shown in Figure 3. These two components are also designed for a specific press. Also shown in Figure 3 is the attachment of brake reaction member 252 to brake adaptor plate 250 and clutch drive ring 332 to clutch reaction hub 300. These two components are identical for all presses of similar size. Next, friction plates 222 and reaction plates 224 are assembled to brake reaction hub 220 and brake reaction member 252; and friction plates 302 and reaction plates 304 are assembled to clutch reaction hub 300 as shown in Figure 4. The friction and reaction plates are identical for all presses of similar size. Finally, brake actuator assembly 254 is attached to brake reaction member 252 and clutch actuator assembly 334 is attached to clutch drive ring 332 as shown in Figure 5. Spacers 267 located between brake actuator assembly 254 and brake reaction member 252 accurately set the clearances required within brake assembly 212 for its proper operation. Due to the commonization of components, the required thickness of spacers 267 are known prior to the assembly of unit 10 to the press, thus eliminating the need for custom fitting the assembly at the time of fitting it to the press. Thus, spacers 267 control the clearances between friction plates 222 and reaction plates 224 and these clearances determine the stroke required for the operation of brake assembly 212. By selecting different thicknesses for spacers 267, the stroke of assembly 212 can be selected. In a similar manner, spacers 347 located between clutch actuator assembly 334 and clutch drive ring 33 3 32 accurately set the clearances desired within clutch assembly 214 for its proper operation. Due to the commonization of components, the required thickness of spacers '347 are also known prior to the assembly of the unit 10 to the press, thus eliminating the need for custom fitting the assembly at the time of fittin it to the press. Thus, spacers 9 3 )47 control the clearances between friction plates _302 and reaction plates 304 and these clearances determine the stroke required for the operation of clutch assembly 214. By selecting different thicknesses for spacers 347, the stroke of assembly 214 can be 25 selected.

The modular and standard component design of brake and clutch unit 210 also provides for the pre-assembly testing of brake actuator assembly 254 and clutch actuator assembly 3 34 at the time of manufacture and not at the time of fitting of unit 210 to the press. This feature significantly reduces the time, complexity and costs associated with brake and clutch unit 2 10.

While the above detailed description describes the preferred embodiment of the present invention, it should be understood that the present invention is susceptible to modification, variation and alteration without deviating from the scope of the subjoined claims.

Claims

A clutch/brake drive comprising:

a brake housing-, a brake hub rotatably disposed with respect to said brake housing; a clutch housing rotatably disposed with respect to said brake housing; a clutch hub rotatably disposed with respect to said clutch housing-, a brake disposed between said brake housing and said brake hub, said brake being movable between an applied condition where said brake hub is locked to said brake housing and a released condition where said brake hub can rotate with respect to said brake housing, said brake comprising a first plurality of circular friction plates alternately splined, respectively, to said brake housing and said brake hub; a clutch disposed between said clutch hub and said clutch housing, said clutch being moveable between an engaged condition where said clutch hub is locked to said clutch housing and a disengaged condition where said clutch housing can rotate relative to said clutch hub, said clutch comprising a second plurality of circular friction plates alternately splined, respectively, to said clutch hub and said clutch housingl lubricating oil disposed within said clutch/brake drive; and a lubricant flow path extending through said clutch/brake drive, said lubricating oil flowing through said lubricant flow path in a direction from said clutch housing radially inward between two of said second plurality of circular friction plates to said clutch hub.
2. The clutch/brake unit according to claim I wherein said lubricant flow path is partially defined by a radial passage in said clutch housing.
3. The clutch/brake unit according to claim I or claim 2, wherein said lubricant flow path is partially defined by an axial passage in said clutch housing.
4. A clutch assembly comprising:

a clutch housing; a clutch hub rotatably disposed with respect to said clutch housing; a clutch disposed between said clutch hub and said clutch housing, said clutch being movable between an engaged condition where said clutch hub is locked to 5 said clutch housing and a disengaged condition where said clutch housing can rotate C.

relative to said clutch hub, said clutch comprising a plurality of circular friction plates alternately splined, respectively, to said clutch hub and said clutch housing; lubricating oil disposed within said clutch assembly; and a lubricant flow path extending through said clutch assembly, said lubricating oil flowing through said lubricant flow path in a direction from said clutch housing radially inward between two of said plurality of circular friction plates to said clutch hub.
5. The clutch assembly according to claim 4, wherein said lubricant now path is partially defined by a radial passage in said clutch housing.
6. The clutch assembly according to claim 4 or 5, wherein said lubricant flow path is partially defined by an axial passage in said clutch housing.

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