Clutch assembly with an oil pump clutch housing and a carrier engaged with a clutch pack outer circumference

The present invention broadly comprises a ring carrier with a wall arranged to engage at least a portion of an outer circumference of a clutch pack for a clutch assembly for a vehicle and a clutch housing with a wall arranged to engage at least a portion of an inner circumference of the clutch pack. The wall for the housing includes at least one opening and the clutch housing is arranged to pump fluid through the opening in the wall independent of the rotation of an output hub for the carrier. The clutch housing can be configured as an inner clutch housing. The clutch housing includes a connecter portion arranged to transfer engine torque to the cylindrical wall from an outer housing of the clutch assembly connected to an engine crankshaft. The present invention also includes a clutch assembly with the ring carrier and clutch housing.

FIELD OF THE INVENTION

The invention relates to improvements in apparatus for transmitting force between a rotary driving unit (such as the engine of a motor vehicle) and a rotary driven unit (such as the variable-speed transmission in the motor vehicle). In particular, the invention relates to a clutch housing engaging an inner circumference of a clutch pack and a ring carrier engaging an outer circumference of a clutch pack. Further, the invention relates to a clutch housing arranged to pump fluid through holes in a wall for the housing whenever a crankshaft is rotating.

BACKGROUND OF THE INVENTION

FIG. 14shows a dual clutch assembly700from commonly assigned, and therefore, uncitable, United States Patent Application No. 2005/0139442 filed Dec. 23, 2004 and published Jun. 30 2005, which application is incorporated herein by reference. InFIG. 14, clutch housing702is connected to outer housing704. Engine torque is transmitted to housing704and transmitted to housing702. Housing702transmits the torque to clutch plates706. In turn, the clutch plates, when engaged, transmit the torque to carrier708. Openings in the wall of the carrier are provided for oil flow through the assembly. The rotation of the carrier generates centripetal force that helps to pump oil through the openings. The carrier only rotates when the clutch pack is engaged. For example, axial force is applied to begin to engage plates in the clutch pack. The plates in the clutch pack go through a slippage mode and then fully engage. In parallel, the carrier begins to rotate, rotation increase through the slippage mode, and synchronizes with the engine torque input when the plates fully engage. The greatest amount of heat is generated during the slippage mode and consequently, oil cooling requirements are greatest during the slippage mode. Therefore, cooling requirements are typically greatest at the beginning of the slippage mode. The oil flow would be greater if the pumping action of the carrier were increased during the slippage mode.

Assembly700uses lever springs, for example, spring710, to provide the axial force necessary to engage plates in a clutch pack. Typically, separate fulcrum elements, such as element712, are used to transfer axial force from the springs to the clutch packs. If the fulcrum were eliminated, the parts count, cost, and complexity of a clutch assembly could be reduced.

Thus, there is a long-felt need for increasing oil flow through a clutch housing while plates in a clutch pack for the housing are slipping. Further, there is a long-felt need for a simplified means of transferring axial force from a lever spring to a clutch pack in a clutch housing.

BRIEF SUMMARY OF THE INVENTION

The present invention broadly comprises a ring carrier with a substantially cylindrical wall arranged to engage at least a portion of an outer circumference of a clutch pack for a clutch assembly for a vehicle. The carrier also includes an output hub. The clutch pack includes an inner circumference and in some aspects, the assembly includes a clutch housing arranged to engage the inner circumference.

The present invention also broadly comprises a clutch housing with a substantially cylindrical wall arranged to engage at least a portion of an inner circumference of a clutch pack in a clutch assembly for a vehicle. The cylindrical wall includes at least one opening, the assembly includes fluid and a rotatable output hub and the clutch housing is arranged to pump the fluid through the at least one opening independent of the rotation of the output hub. The clutch housing is arranged to pump the fluid through the at least one opening whenever an outer housing for the assembly is rotating. The outer housing is connected to an engine crankshaft for the vehicle and to the clutch housing. In some aspects, the clutch housing is configured as an inner clutch housing for the assembly.

The present invention further broadly comprises a clutch assembly for a vehicle including a clutch housing arranged to engage an inner circumference of a clutch pack and a carrier arranged to engage an outer circumference of the clutch pack. The carrier includes a substantially cylindrical carrier wall arranged to engage the outer circumference. The clutch housing includes a substantially cylindrical housing wall arranged to engage the inner circumference. In some aspects the assembly includes fluid, the carrier includes a rotatable output hub, the housing wall includes at least one opening, and the clutch housing is arranged to pump the fluid through the at least one opening independent of the rotation of the output hub. The clutch housing also is arranged to pump the fluid through the at least one opening whenever an outer housing for the assembly is rotating. The outer housing is connected to an engine crankshaft for the vehicle and to the clutch housing.

The clutch housing is arranged to transfer torque from the engine to the clutch pack. The clutch housing further comprises an annular housing disc connected to the outer housing of the assembly. The outer housing is connected to an engine crankshaft for the vehicle. In some aspects the first annular housing disc includes at least one connection point, the assembly includes a fulcrum engaged with the clutch pack and a first lever spring, the first lever spring has an outer circumference engaged with the at least one connection point, and the first spring is arranged to engage the fulcrum. In some aspects, the assembly includes a second lever spring and the clutch housing includes a second annular disc with a fulcrum portion arranged to engage the second lever spring and a clutch portion arranged to engage the clutch pack. In some aspects, the clutch housing is an inner clutch housing.

The present invention also broadly comprises a method for optimizing fluid flow through a clutch housing in a clutch assembly in a vehicle.

It is a general object of the present invention to provide a clutch housing able to pump cooling fluid independent of the rotation of an output hub for an assembly for the clutch housing.

It is another object of the present invention to provide a clutch housing able to pump cooling fluid whenever a crankshaft, associated with a clutch assembly for the clutch housing, is rotating.

It is a further object of the present invention to provide a clutch housing that provides maximum oil flow while plates in a clutch pack for the housing are slipping.

These and other objects and advantages of the present invention will be readily appreciable from the following description of preferred embodiments of the invention and from the accompanying drawings and claims.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1,2, and3are perspective back, back, and side views, respectively, of ring carrier10. The following should be viewed in light ofFIGS. 1 through 3. Ring carrier10includes ring carrier wall12and output connection section14. In general, wall12is substantially cylindrical about longitudinal axis16. That is, although wall12may be formed with splines or other surface features, the wall, splines, or surface features are in a cylindrical configuration. However, it should be understood that wall12is not limited to the shape shown in the figures and that other shapes for wall12are included within the spirit and scope of the invention as claimed. For example, wall12is not limited to a particular height17or diameter18. Section14extends from wall12, specifically, radially inward with respect to the wall and axis16and is connected to output hub20. Ring carrier10is described in the context of a clutch assembly infra. Wall12and section14are integral, or formed from a same piece of material, in the figures. However, it should be understood that the wall and section can be formed from separate, joined pieces. Such pieces can be attached, secured, or connected by any means known in the art, including, but not limited to welding, riveting, or press fitting.

In some aspects, section14is a continuous/integral piece from wall12to hub20. It should be understood that section14is not limited to the shape shown in the figures and that other shapes for section14are included within the spirit and scope of the invention as claimed. For example, section14is not limited to a particular radial dimension22. In some aspects (not shown), two or more fixedly attached segments or pieces form section14. The two or more segments are joined by any means known in the art, including, but not limited to, welding or riveting. Hub20can be connected to section14by any means known in the art, including but not limited to, riveting and welding. Hub20is configured for connection to an input shaft for a transmission (not shown) by any means known in the art, including, but not limited to, splines, notches, welding, or riveting.

When disposed in a clutch assembly, ring carrier10is arranged to receive and engage a clutch pack (not shown). Typically, ring carrier10is used with an inner clutch housing in a clutch assembly, however, it should be understood that other uses for the carrier are included in the spirit and scope of the claimed invention. Specifically, wall12includes inner surface24, arranged to engage at least a portion of an outer circumference of the clutch pack. Any means known in the art can be used to engage surface24and the clutch pack, for example, complementary splines and notches. In some aspects, the carrier is used in a clutch assembly including a clutch housing (not shown, but described infra) engaged to an inner circumference of the clutch pack. The wall of ring carrier10is arranged to a receive engine torque from the clutch pack and transfer the torque to output hub20through segment14. The housing receives the engine torque and transfers the torque to the clutch pack. In contrast, in the arrangement shown inFIG. 14, the inner clutch housing receives the torque and transfers the torque to the outer circumference of the clutch pack. In some aspects, openings26in wall12enable cooling fluid flow.

In some aspects, ring carrier10is stamped, reducing fabricating cost and complexity. However, it should be understood that other fabrication methods can be used to form ring carrier10.

FIGS. 4,5, and6are perspective back, back, and side views, respectively, of present invention clutch housing100. The following should be viewed in light ofFIGS. 4 through 6. Clutch housing100includes wall102and connector portion104. Wall102is substantially cylindrical, as described for wall12inFIGS. 1 through 3. However, it should be understood that wall102is not limited to the shape shown in the figures and that other shapes for wall102are included within the spirit and scope of the invention as claimed. For example, wall102is not limited to a particular height105or diameter106. Wall102, specifically outer surface108is arranged to engage at least a portion of an inner circumference of a clutch pack (not shown) for a clutch housing (not shown). Clutch housing100is described in the context of a clutch assembly infra.

Portion104is arranged to transfer engine torque to wall102. In some aspects, portion104is an annular disc substantially orthogonal to wall102with respect to longitudinal axis110. However, it should be understood that portion104is not limited to the shape shown in the figures and that other shapes for portion104are included within the spirit and scope of the invention as claimed. For example, portion104is not limited to a particular diameter112. In some aspects, the crankshaft (not shown) for a vehicle (not shown) in which the clutch assembly is installed, is connected to an outer housing of the assembly. Torque from the engine of the vehicle is transferred from the crankshaft to the outer housing to clutch housing100. The connection of clutch housing100to an outer housing is discussed infra.

Wall102includes at least one opening116. Clutch housing100is not limited to the number, size, configuration, and orientation of openings shown and it should be understood that other numbers, sizes, configurations, or orientations of openings are included in the spirit and scope of the claimed invention. A wet clutch assembly includes a fluid, typically an oil, to cool the assembly, in particular, clutches or clutch packs in the assembly. Openings116are configured to enable fluid flow radially outward from axis110, for example, in direction118, from cavity120, past outer circumference108. The rotation of clutch housing100about axis110creates centripetal force in direction118.

In some aspects, clutch housing100is stamped, reducing fabricating cost and complexity. However, it should be understood that other fabrication methods can be used to form clutch housing100.

FIG. 7is an exploded back view of present invention dual clutch assembly200.

FIG. 8is a side view of assembly200.

FIG. 10is the cross-section of assembly200with background lines removed. The following should be viewed in light ofFIGS. 1 through 10. Assembly200includes ring carrier10and clutch housing100. The assembly also includes outer housing202, clutch pack203(shown inside housing202), clutch pack204, dam/fulcrum206, snap rings208and210, dam/fulcrum212, outer lever spring214, and inner lever spring216. Assembly200can be formed in any way known in the art. Therefore, it should be understood that the present invention is not limited to use with the number, type, and configuration of components shown for assembly200and other number, type, and configuration of components can be used with the present invention.

It should be understood that any means known in the art, for example, complimentary splines and notches or welding, can be used to connect clutch housing100to outer housing202. In addition, in some aspects, a tab and slot arrangement as described in the commonly assigned U.S. patent application Ser. No. 11/706,656 titled “CLUTCH HOUSING WITH WIDE LEVER SPRING RETENTION SLOTS AND CLUTCH HOUSING WITH AXIALLY OFF-SET TABS,” inventor Adam Uhler, filed Feb. 15, 2007, can be used. For example, tabs114engage with openings218in housing202to rotationally lock clutch housing100with housing202. Hub220, is connected to a crankshaft (not shown) for an engine and torque from the engine is transferred from hub220to clutch housing100via openings218and tabs114. Any means known in the art can be used to connect hub220and the crankshaft. Ring carrier10and housing100are connected to clutch pack204using any means known in the art, for example, a spline and notch arrangement.

Spring214can be engaged with housing202using any means known in the art. In addition, in some aspects, an arrangement of spring tabs and slots in the housing as described in the commonly assigned U.S. patent application Ser. No. 11/706,584 titled “CLUTCH HOUSING WITH LEVER SPRING RETENTION SLOTS AND METHOD OF INSTALLING A LEVER SPRING,” inventors Todd Sturgin and Adam Uhler, filed Feb. 15, 2007, can be used. For example, tabs221of spring214are inserted in openings218.

As force is applied in axial direction222by spring216on clutch pack204, the clutch pack engages and engine torque is transferred to ring carrier10. Hub20is connected to an input shaft for a transmission (not shown) and the hub transfers the torque to the shaft. Any means known in the art can be used to connect hub20and the shaft.

It should be understood that any means known in the art, for example, complimentary splines and notches can be used to connect clutch pack203to housing202. In addition, in some aspects, a tab and slot arrangement as described in the commonly assigned U.S. patent application Ser. No. 11/706,661 titled “CLUTCH HOUSING WITH OPENINGS TO ENGAGE A CLUTCH PLATE,” inventors Sturgin et al., filed Feb. 15, 2007, can be used.

FIG. 11is a cross-section of present invention dual clutch assembly300. Assembly300includes ring carrier302and clutch housing304. The following should be viewed in light ofFIGS. 1though11. The ring carrier and clutch housing are similar in function and configuration to ring carrier10, described inFIGS. 1 through 3, and clutch housing100, described inFIGS. 4 through 7, respectively and the discussions supra regarding ring carrier10and clutch housing100are generally applicable to ring carrier302and clutch housing304, respectively. Ring carrier302, specifically hub306of portion308, is connected to an input shaft for a transmission (not shown). Any means known in the art can be used to connect hub306and the shaft. Portion312is connected to housing314using any means known in the art, for example, snap ring315. In addition, in some aspects, the tabs arrangement described forFIGS. 4 through 6can be used. Inner clutch pack316is connected to housing wall318and carrier wall320using any means known in the art, for example, the spline and notch arrangements shown in the figures.

Assembly300includes inner lever spring322engaged with connection elements324. In some aspects, elements324are tabs or other such protrusions from portion312. Fulcrum326is engaged with plate328and passes through openings330in the housing. Since clutch housing304is axially fixed with respect to housing314by snap ring315, clutch housing304provides the necessary reaction points for the spring. Elements324are located a radial distance332from longitudinal axis334of assembly300. In some aspects, distance332is less than radial distance336. In some aspects, distance332is substantially equal to radial distance338from axis334to carrier wall320. By substantially equal, we mean that distance332may be slightly less than, equal to, or slightly more than distance338. Thus, it is not necessary to extend spring322all the way to housing314, reducing the outside diameter of the spring. In this manner, the size, weight, and cost of the spring are all advantageously reduced. It should be understood that assembly300is not limited to a particular distance332and that distance332can be selected according to the material characteristics of spring322and operational parameters for assembly300.

Outer housing314is connected to hub340, which is connected to a crankshaft (not shown) for an engine (not shown). Torque from the engine is thus transferred from housing314to clutch pack316via portion312. In response to axial force in direction342, lever spring322reacts against elements324to move fulcrum326in direction342, engaging clutch pack316. Thus, engine torque is transferred from clutch housing304to ring carrier302via the clutch pack. Ring carrier302then transfers the torque to the output hub. It should be understood that fulcrum326and element324are not limited to the shapes, sizes, and configurations shown in the figures and that other respective shapes, sizes, and configurations are included in the spirit and scope of the claimed invention.

Ring carriers302and344are both able to move axially in assembly300. Therefore, thrust bearing346is provided to separate outer housing314and carrier344and thrust bearing348is provided to separate carriers344and302. That is, as axial forces push ring housing314and carriers302and344in direction342, the thrust bearings separate the housing and carriers as described supra and allow ring carriers302and344and clutch housing314to rotate independently about axis334.

As noted supra, cooling fluid is used in clutch assemblies, such as assembly300to cool clutch packs, such as clutch packs316and341. Fluid flow352is introduced to cavity354, formed in part by wall318. Holes in wall318, similar to openings116shown inFIGS. 4 through 6, enable flow352to continue past wall318to the clutch packs. That is, the fluid flows through the openings. Returning toFIGS. 4 through 6, the centripetal force generated by the rotation of clutch housing100boosts the flow of fluid though openings116. Therefore, increasing the time period, during the operation of a clutch assembly, in which the clutch housing is rotating optimizes the flow of fluid through the openings. Increasing the flow through the openings increases the cooling of the clutch packs, optimizing the life-time and performance of the clutch packs. Returning toFIG. 11, engine torque is directly linked to carrier304via housing314and hub340. That is, whenever the crankshaft and the outer housing are turning, carrier304is turning and generating centripetal force to abet the fluid flow. Alternately stated, the flow of fluid to clutch pack316is independent of the rotation of an output hub for the assembly. The preceding arrangement optimizes the time period mentioned supra, since clutch housing304is rotating whenever the engine is operating and the crankshaft is rotating. Thus, the preceding arrangement advantageously optimizes the oil flow to the clutch packs. Returning toFIG. 14, in contrast and as described supra, the carrier in assembly700only rotates when the clutch pack is engaged and engine torque is transferred from the housing through the clutch plates to the carrier.

It should be understood that the present invention is not limited to use with the number, type, and configuration of ancillary components, for example, as shown for assembly300, and other number, type, and configuration of ancillary components can be used with the present invention.

FIG. 12is a cross-section of present invention dual clutch assembly400. Assembly400includes ring carrier402and clutch housing404. The following should be viewed in light ofFIGS. 1though12. Ring carrier402is connected to output hub406. Clutch housing404is connected to outer housing414. Inner clutch pack416is connected to clutch housing404and ring carrier402. Outer housing414is connected to hub440, which is connected to a crankshaft (not shown) for an engine (not shown). Clutch pack441engages outer housing414. The components of assembly400are similar in function and configuration to the respective components shown for assembly300inFIG. 11, except for lever spring460, and the discussions supra regarding such components in assembly300are applicable toFIG. 12. In particular, assembly400does not include a snap ring to axially fix housing404. Instead, end462is axially fixed by the housing itself.

FIG. 13is a cross-section of present invention dual clutch assembly500. The following should be viewed in light ofFIGS. 1though13. Assembly500includes ring carrier502and clutch housing504. Ring carrier502is connected to output hub506. Clutch housing504is connected to outer housing514. Inner clutch pack516is connected to clutch housing504and ring carrier502. Outer housing514is connected to hub540, which is connected to a crankshaft (not shown) for an engine (not shown). Clutch pack541engages outer housing514. Lever spring560engages outer housing514. The components of assembly500are similar in function and configuration to the respective components shown for assembly400inFIG. 12, except as follows, and the discussions supra regarding such components in assembly400are applicable toFIG. 13. Rather than including a separate fulcrum, such as fulcrum326inFIG. 11, housing504includes fulcrum portion572to engage spring560and clutch portion574engaged with pack516. As axial force is applied to spring560in direction576, spring560engages portion572and moves portion574in direction576, engaging clutch pack516. The configuration shown for carrier504eliminates the need for a separate fulcrum and thus reduces the parts count and complexity of assembly500.

FIG. 15is a flow chart illustrating a present invention method for optimizing fluid flow through a clutch housing in a clutch assembly in a vehicle. Although the method inFIG. 15is depicted as a sequence of numbered steps for clarity, no order should be inferred from the numbering unless explicitly stated. The method starts at Step600. Step602engages an inner circumference of a clutch pack with the clutch housing. Step604rotationally locks the clutch housing with an engine crankshaft. In some aspects, the assembly comprises a ring carrier and an output hub and the clutch pack further comprises an outer circumference. Then, Step606engages the outer circumference of the clutch pack with the ring carrier and Step608rotationally locks the ring carrier and the output hub. In some aspects, the assembly further comprises cooling fluid, the engine comprises a crankshaft, and the clutch housing comprises a wall engaging the inner circumference and having at least one opening. Then, Step610rotates the clutch housing independent of the output hub and Step612pumps the fluid through the at least one opening whenever the crankshaft is rotating.

Respective present invention clutch housings and carriers have been shown in dual clutch assemblies200,300,400, and500(FIGS. 7, and11through13, respectively). However, it should be understood that present invention clutch housings and carriers are not limited to dual clutch assemblies. For example, a present invention clutch housing and carrier can be used in a single clutch arrangement (not shown), for example, in a launch clutch.

It should be understood that any means known in the art can be used to adjust the clutch assemblies shown in the figures. In addition, in some aspects, the method described in the commonly assigned U.S. patent application Ser. No. 11/706,663 titled “DUAL CLUTCH PACK DUAL OPERATING CLUTCH AND METHOD FOR ADJUSTING SAME,” inventors Uhler et al., filed Feb. 15, 2007, can be used.