Hybrid module including a torque converter inside an electric motor and having a remote compensation chamber

Abstract

A hybrid power module includes an electric motor having a rotor and a stator for driving the rotor; a torque converter located downstream of the electric motor; and a rotor input clutch capable of selectively engaging and disengaging to drivingly connect or disconnect the rotor with the output of the engine crankshaft. The rotor input clutch includes a piston and a clutch plate. The piston is configured to be pressed into the clutch plate in a first axial direction to engage with the rotor input clutch via an increase in pressure of a fluid in an apply chamber. The hybrid power module also includes a compensation chamber assembly. The compensation chamber assembly and the piston define a compensation chamber radially offset from the apply chamber. The compensation chamber assembly is configured to apply a force to the piston in a second axial direction opposite to the first axial direction via an increase in pressure of the fluid in the compensation chamber.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. non-provisional application No. 16 / 871,702, filed May 11, 2020, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to hybrid modules and, more particularly, to a hybrid module including a torque converter within an electric motor. Background Art

[0004] Hybrid modules comprising an electric motor and a torque converter are known. Summary of the Invention

[0005] A hybrid power module is configured to be arranged in a torque path upstream of a transmission and downstream of an internal combustion engine, the hybrid power module comprising: an electric motor including a rotor and a stator for driving the rotor; a torque converter located downstream of the electric motor; and a rotor input clutch capable of selectively engaging and disengaging to drivingly connect the rotor to or disconnect the rotor from the output of the engine crankshaft. The rotor input clutch comprises a piston and at least one clutch plate. The piston is configured to be pressed into the at least one clutch plate in a first axial direction to engage the rotor input clutch via an increase in pressure of a fluid in an apply chamber. The hybrid power module further comprises a compensation chamber assembly. The compensation chamber assembly and the piston define a compensation chamber radially offset from the apply chamber. The compensation chamber assembly is configured to apply a force to the piston in a second axial direction opposite to the first axial direction via an increase in pressure of the fluid in the compensation chamber.

[0006] A method for constructing a hybrid power module configured to be arranged in a torque path upstream of a transmission and downstream of an internal combustion engine, the method comprising: providing an electric motor including a rotor and a stator for driving the rotor; providing a torque converter downstream of the electric motor; and drivingly coupling an output of a rotor input clutch to the rotor. The rotor input clutch is selectively engageable and disengageable to drivingly connect the rotor to the output of the engine crankshaft or to disconnect the rotor from the output of the engine crankshaft. The rotor input clutch comprises a piston and at least one clutch plate. The piston is configured to be pressed into the at least one clutch plate in a first axial direction to engage the rotor input clutch via an increase in pressure of a fluid in an apply chamber. The method further comprises providing a compensating chamber assembly on the piston, such that the compensating chamber assembly and the piston define a compensating chamber radially offset from the apply chamber. The compensating chamber assembly is configured to apply a force to the piston in a second axial direction opposite to the first axial direction via an increase in pressure of the fluid in the compensating chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present disclosure is described below with reference to the following drawings, in which:

[0008] Figure 1 A hybrid module according to an embodiment of the present disclosure is shown; and

[0009] Figure 2 Shown Figure 1 The illustration of the hybrid module shown in FIG. 1 has an enlarged view of a portion of the remote compensation chamber assembly. DETAILED DESCRIPTION

[0010] The present disclosure provides a hybrid power module that includes a torque converter within an electric motor. The hybrid power module includes a compensation chamber, radially outside a clutch piston, for connecting the electric motor's rotor to the output of an internal combustion engine. Rotating the reservoir chamber generates a hydraulic head pressure acting on the compensation chamber. The reservoir inlet diameter is calculated to provide the necessary compensation force. Oil from an application circuit for engaging the clutch is supplied to the reservoir chamber, for example, by injection.

[0011] Figure 1A radial cross-section of a hybrid module 10 according to an embodiment of the present invention is shown. Module 10 includes a first side portion 10a configured for attachment to an internal combustion engine and a second side portion 10b configured for attachment to a transmission input shaft. Module 10 includes a flywheel assembly 12 having an input section 12a configured to connect to the crankshaft 14 of the internal combustion engine via bolts 16, and an output section 12b configured to connect to a drive hub 18. Flywheel assembly 12 includes a flywheel 12c secured to input section 12a and two spring packs driven by flywheel 12c: a radially outer spring pack 12d and a radially inner spring pack 12e. Torque is transmitted from flywheel 12c to outer spring pack 12d, then to inner spring pack 12e, and then to output section 12b. The inner circumferential surface of output section 12b is non-rotatably secured to the outer circumferential surface of drive hub 18.

[0012] Drive hub 18 extends axially away from flywheel assembly 12 to couple with input portion 20 of rotor input clutch 22. Input portion 20 can be formed as a single piece with drive hub 18 and has a cup-like shape defined by a radially extending plate segment 20a extending from drive hub 18 and an annular rim segment 20b extending axially from the radially outer edge of segment 20a toward flywheel assembly 12. In other embodiments, input portion 20 can often be manufactured as a two-piece structure and non-rotatably secured by welding or a spline / snap ring / riveted connection. Annular rim segment 20b defines the inner clutch plate carrier of clutch 22. Rotor input clutch 22 includes at least one input plate 24a, at least one output plate 24b, and a piston 26 for forcing plates 24a, 24b into axial frictional engagement to transfer torque from crankshaft 14 via flywheel assembly 12 and drive hub 18 to rotor 28 of electric motor 30. The rotor input clutch 22 is arranged and configured for drivingly connecting the rotor 28 to the internal combustion engine.

[0013] The electric motor 30 includes a stator 32 surrounding a rotor 28, wherein the stator 32 is non-rotatably fixed to a housing 34 of the hybrid module 10. Because the rotor 28 includes a plurality of annular rotor segments, each of which includes a plurality of circumferentially spaced magnets that, in at least some preferred embodiments, are permanent magnets energized by current in the coils of the stator 32, the rotor 28 rotates about the central axis CA of the hybrid module 10 when current is supplied to the coils of the stator 32. As used herein, the terms axially, radially, and circumferentially are used relative to the central axis CA. In some embodiments, the electric motor 30 is a generator or can function as a motor or generator. The rotor 28 is non-rotatably fixed to a cylindrical section 36a of a rotor carrier 36 at its inner circumferential surface, such that the rotor 28 and the rotor carrier 36 rotate together about the central axis CA.

[0014] Electric motor 32 also includes a rotor clamping ring 37a secured to cylindrical segment 36a for axially retaining rotor 24 on rotor carrier hub 28. Rotor clamping ring 37a is disposed at a first axial end of rotor carrier 36, opposite a second axial end of rotor carrier 36, comprising radially extending disk-shaped segment 36b, such that the magnet segments of rotor 28 are axially clamped between segment 36b and ring 37a. A first non-ferrous metal plate 37b is axially disposed between rotor 28 and ring 37a, and a second non-ferrous metal plate 37c is axially disposed between rotor 28 and segment 36b. Plates 37b, 37c may be formed of aluminum and contact the rotor magnets to prevent eddy currents, which essentially short-circuit the magnetic flux field and lead to lower electric motor efficiency.

[0015] The rotor flange 38 is fixed to the rotor carrier 36 in a non-rotatable manner and extends radially inward from the cylindrical section 36a. The rotor hub 40, through which the central axis CA passes, is fixed to the inner radial end of the rotor flange 38 in a non-rotatable manner, so that the rotor flange 38 is directly connected to the rotor carrier 36 and the rotor hub 40. Figure 1 In the embodiment of FIG, the rotor carrier 36, the rotor flange 38, and the rotor hub 40 are formed together as a single piece. The rotor hub 40 is received in a blind hole in the drive hub 18, wherein the rotor hub 40 is centered in the drive hub 18 by a bushing 42. The bushing 42 contacts the inner circumferential surface of the drive hub 18 and the outer circumferential surface of the rotor hub 40 at the blind hole, so that the rotor hub 40 can rotate relative to the drive hub 18.

[0016] The module 10 also includes a rotor output clutch 44, which forms a lockup clutch for a hydraulic torque converter 45 arranged radially inside the rotor 28. The rotor output clutch 44 includes at least one input plate 46a, at least one output plate 46b, and a piston 48 for forcing the plates 46a, 46b axially together into frictional engagement to transfer torque from the rotor 28 to the transmission input shaft 50 of the planetary transmission via an inner clutch plate carrier 52, a torque output plate 53, and a turbine hub 54. The rotor output clutch 44 is arranged in parallel with the hydraulic torque converter 45 for drivingly connecting the rotor 28 to the transmission input shaft 50.

[0017] Rotor carrier 36 includes teeth or splines 56a on its inner circumference and forms an outer clutch plate carrier 56, to which clutch output plate 46a is non-rotatably connected and axially slidable. Inner clutch plate carrier 52 includes teeth or splines on its outer circumference, to which clutch output plate 46b is non-rotatably connected and axially slidable. The radially outer end of piston 48 can slide axially and sealingly along the inner circumferential surface of rotor carrier 36, and the radially inner axial extension of piston 48 can slide axially along a support plate 58, which is non-rotatably fixed to rotor flange 38, such as by laser welding. Piston 48 can slide axially away from rotor flange 38 to force clutch plates 46a, 46b into clutch backing plate 60, thereby engaging rotor output clutch 44 and thereby bypassing torque converter 45. The piston 48 is also non-rotatably connected to the support plate 58, such as via a toothed connection at the inner diameter of the piston 48 to the outer diameter of the support plate 58. In other embodiments, the support plate 58 may be omitted and the piston 48 may directly engage the turbine hub 54 and be connected to the rotor flange 38 via leaf springs.

[0018] The torque converter 45 includes a hydraulic coupling device formed by an impeller 62 and a turbine 64. A cover 68, which forms the housing for the impeller 62 and delimits the transmission side of the torque converter 45, is non-rotatably fixed, for example, by welding, to the inner circumferential surface of the cover forming the engine side of the torque converter 45 on the rotor carrier 38. The impeller 62 includes a plurality of impeller blades 62a fixed to the cover 68. The turbine 64 includes a turbine housing 64a supporting a plurality of turbine blades 64b. When the clutch 44 is disengaged, the impeller 62 receives torque input from the rotor 28, and the fluid flows from the impeller blades 62a to the turbine blades 64b, driving the turbine 64. The turbine 64 then drives the transmission input shaft 50 via its non-rotatably connected connection to the turbine hub 54. The torque converter 45 also includes a stator 66 located axially between the turbine 64 and the impeller 62. The stator includes a plurality of circumferentially spaced stator blades 66a that redirect fluid flowing from the turbine blades 64b before reaching the impeller blades 62a to improve the efficiency of the torque converter 45. The stator 66 is fixed to the non-rotatable shaft 70 by a one-way clutch 72.

[0019] The housing 34 encloses the electric motor 30, the torque converter 45, and the clutches 22 and 44. The housing 34 includes a cylindrical housing section 34a, which is fixed to the stator 32 and radially surrounds the stator; a transmission side plate section 34b, which axially faces the motor 30 and a portion of the cover 68 and extends radially inward from the transmission-side end of the section 34a; and an engine side plate section 34c, which is disposed between the clutch 22 and the flywheel assembly 12 and extends radially inward from the engine-side end of the section 34a. The housing 34 also includes a rim section 34d, which radially surrounds the flywheel assembly 12 and protrudes axially from the transmission-side portion of the section 34c.

[0020] The hybrid module 10 also includes a compensation chamber assembly 74 located axially between the clutch 22 and the engine side plate section 34 b.

[0021] Figure 2 Shown Figure 1 The hybrid module 10 shown in FIG has an enlarged view of a portion of a compensation chamber assembly 74. The compensation chamber assembly 74 includes a first compensation portion 76 for defining a balance chamber 78 having the piston 26 and a second compensation portion 80 for defining a rotating reservoir 82.

[0022] Piston 26 includes a radially inner portion 26a, a middle portion 26b located radially outward of inner portion 26a, and a radially outer portion 26c located radially outward of middle portion 26b. Inner portion 26a is resiliently connected to support plate 83a via spring 83b and includes a radially inner end that contacts first seal 84a and a radially outer end that contacts second seal 84b. Middle portion 26b includes a first radially extending surface for contacting one of clutch plates 24b and an opposing second radially extending surface for contacting second compensating portion 80. Radially outer portion 26c includes an inner axially extending section 26d that defines the radially inner boundary of balancing chamber 78, and an outer radially extending section 26e that defines the engine-side axial boundary of balancing chamber 78. Inner axially extending section 26d includes a radially extending channel 86a that provides fluid radially outward to balancing chamber 78. The inner circumferential surface of the inner axially extending section 26d contacts the third seal 84c, while the outer circumferential surface of the inner axially extending section 26d contacts the fourth seal 84e. The outer circumferential surface of the outer radially extending section 26e contacts the fifth seal 84e.

[0023] The first compensating portion 76 axially abuts the axial ends of the rotor clamping ring 37a and the cylindrical section 36a of the rotor carrier 36, and sealingly abuts the piston 26 at two different locations—via seals 84d and 84e. The first compensating portion 76 is non-rotatably fixed to the rotor carrier 36, for example, via welding or bolts, and the portion 80 is fixed to the component 76, and thus to the rotor carrier 36, via welding or bolts. The first compensating portion 76 includes a stepped inner circumferential surface defined by a radially inner narrower section 76a and a radially outer wider section 76b. The radially extending surface of the radially inner narrower section 76a and the inner circumferential surface of the radially outer wider section 76b define a portion of the chamber 78.

[0024] Second compensating portion 80 includes a radially inner portion 80a, which forms an axially extending hub of portion 80; an intermediate portion 80b, which extends radially outward from portion 80a; and a radially outer portion 80c, which extends radially outward from portion 80b. Radially inner portion 80a axially abuts radially extending plate segment 20a of input portion 20 via thrust washer 88 and radially and axially contacts outer race 90a of bearing 90. The inner race 90b of bearing 90 is radially supported on radially inner hub portion 92a of housing segment 34c and is rotatable relative to outer race 90a via rolling elements 90c. Hub portion 92a is rotatably supported on the outer circumferential surface of drive hub 18 via outer race 94a of bearing 94. The inner race 94b of bearing 94 is radially supported on the outer circumferential surface of drive hub 18 and is rotatable relative to outer race 94a via rolling elements 94c. The hub portion 92a is sealed relative to the drive hub 18 by seals 18a, 18b. The inner peripheral surface of the radially inner portion 80a is sealed relative to the outer peripheral surface of the hub portion 92a via a seal 84f.

[0025] Intermediate portion 80b includes a passage 86b that passes through the intermediate portion for supplying fluid to an apply chamber 96a for forcing piston 26 to axially press plates 24a, 24b against rotor flange 38, thereby forming a clutch backing for clutch 22. Radially outward of seal 84f, intermediate portion 80b is sealed against a protrusion on housing segment 34c by seal 84g. Housing segment 34c includes a radially extending passage 86c therein for supplying fluid via an axially extending passage 86d in housing segment 34c, through a space 96b defined between seals 84f, 84g, and then through passage 86b to apply chamber 96a. When apply chamber 96a becomes fully pressurized, piston 26 is forced in an axial direction D1 to engage clutch 22. Housing segment 34b is formed by two axially offset wall segments 92b, 92c, defining radially extending passage 86c therebetween. Hub portion 92a also includes a channel 92d formed therein for supplying fluid from channel 86c for splash cooling clutch 22, wherein the coolant exits clutch 22 via outlet aperture 36c formed in rotor carrier 36. Radially outwardly of seal 84g, intermediate segment 80b defines a rotating reservoir 82 for supplying fluid from radially extending channel 86c to balancing chamber 78. Intermediate segment 80b is divided into two plate segments 81a, 81b defining rotating reservoir 82, wherein plate segment 81b is formed from the main portion of portion 80, and plate segment 81a is formed from a secondary plate secured to the main portion, for example, by laser welding. Wall segment 92b is provided with a supply port 86e for supplying fluid from channel 86c to reservoir 82 through inlet 82a of reservoir 82, which is formed by the inner diameter of plate segment 81a and intermediate segment 80b. Radially outwardly of plate segment 81b, intermediate segment 80b includes an axially projecting segment 81c projecting from plate segment 81b. Projecting segment 81c is provided with a passage 86f for providing fluid from rotary reservoir 82 radially outwardly to chamber 78 via passage 86a in piston 26.

[0026] The outer portion 80c is provided with a drain hole 86g axially therethrough for preventing a pressure buildup in the chamber 78 due to leakage from the seals 84c, 84e. The outer portion 80c is held in axial contact with the radially outer wider section 76b of the portion 76. The outer portion 80c and the plate section 81a are axially spaced from the wall section 92b to provide a space 97 into which the hole 86g opens.

[0027] During operation of the hybrid module, compensation chamber 78 is filled with fluid to apply a force in an axial direction D2 opposite to the clutch apply direction D1 to counteract the effects of rotational dynamic pressure on clutch 22. Compensation chamber 78 is advantageously radially offset from apply chamber 96a and from clutch contact location 99, where piston 26 contacts one of clutch plates 24b by being located radially outboard of location 99 and the apply chamber. In contrast to designs in which the compensation chamber and apply chamber 96a are axially stacked and radially overlap or radially aligned with the apply chamber 96a—i.e., where a line extending parallel to central axis CA can be drawn through the compensation chamber and the apply chamber—the radial offset of chamber 78 relative to apply chamber 96a saves axial space.

[0028] In the foregoing description, the present invention has been described with reference to specific exemplary embodiments and examples thereof. However, it will be apparent that various modifications and changes may be made thereto without departing from the broader spirit and scope of the present invention as set forth in the appended claims. Accordingly, the description and drawings are to be regarded in an illustrative manner rather than in a restrictive sense.

[0029] Description of Reference Numerals

[0030] CA Central Axis

[0031] D1, D2 axial direction

[0032] 10 Hybrid Module

[0033] 10a Anterior side

[0034] 10b rear side

[0035] 12 Flywheel assembly

[0036] 12a Input section

[0037] 12b Output section

[0038] 12c cassette

[0039] 12d radial outer spring assembly

[0040] 12e radial inner spring set

[0041] 14 Crankshaft

[0042] 16 bolts

[0043] 18 drive hub

[0044] 20 Input section

[0045] 20a Radially extending plate segment

[0046] 20b Annular rim segment

[0047] 22 Rotor input clutch

[0048] 24a Clutch input plate

[0049] 24b Clutch output plate

[0050] 26 Piston

[0051] 26a Radially inner portion

[0052] 26b Middle section

[0053] 26c radially outer portion

[0054] 26d Inner axially extending section of the radially outer portion

[0055] 26e Outer radially extending section of the radially outer portion

[0056] 28 rotors

[0057] 30 electric motors

[0058] 32 stator

[0059] 34 Shell

[0060] 34a Cylindrical housing section

[0061] 34b Transmission side plate section

[0062] 34c engine side panel section

[0063] 34d edge segment

[0064] 36 rotor carrier

[0065] 36a Cylindrical section

[0066] 36b Radially extending disc-shaped segment

[0067] 37a Rotor clamping ring

[0068] 37b, 37c Nonferrous metal plates

[0069] 38 rotor flange

[0070] 40 rotor hub

[0071] 42 Bushing

[0072] 44 Rotor output clutch

[0073] 45 hydraulic torque converter

[0074] 46a Clutch input plate

[0075] 46b Clutch output plate

[0076] 48 piston

[0077] 50 Transmission input shaft

[0078] 52 Inner clutch plate carrier

[0079] 53 Torque output plate

[0080] 54 turbine hub

[0081] 56 Outer clutch plate carrier

[0082] 56a Teeth or splines

[0083] 58 Support Plate

[0084] 60 Clutch backing plate

[0085] 62 impeller

[0086] 62a Impeller blades

[0087] 64 Turbine

[0088] 64a turbine housing

[0089] 64b turbine blades

[0090] 66 stator

[0091] 68 Cover

[0092] 70 Non-rotatable shaft

[0093] 72 One-way clutch

[0094] 74 Compensation chamber assembly

[0095] 76 First Compensation Part

[0096] 76a Radially inner narrow section

[0097] 76b radially outer wider section

[0098] 78 Balance Room

[0099] 80 Second compensation part

[0100] 80a radially inner portion

[0101] 80b middle section

[0102] 80c radially outer portion

[0103] 81a, 81b plate segments

[0104] 82 Rotary Receiver

[0105] 83a Support plate

[0106] 83b spring

[0107] 84a First seal

[0108] 84b Second seal

[0109] 84c Third seal

[0110] 84d Fourth seal

[0111] 84e Fifth Seal

[0112] 84f Sixth seal

[0113] 84g Seventh Seal

[0114] 86a radial extension channel

[0115] Channel 86b

[0116] 86c radial extension channel

[0117] 88 thrust washer

[0118] 90 bearings

[0119] 90a outer ring

[0120] 90b inner ring

[0121] 90c rolling element

[0122] 92a radial inner hub portion

[0123] 92b, 92c wall segments

[0124] Channel 92d

[0125] 94 bearings

[0126] 94a outer ring

[0127] 94b inner circle

[0128] 94c rolling element

[0129] 96a Application Chamber

[0130] 96b Space

[0131] 97 Space

[0132] 99 position

Claims

1. A hybrid module configured for placement in a torque path upstream of a transmission and downstream of an internal combustion engine, the hybrid module comprising: an electric motor comprising a rotor and a stator for driving the rotor; a torque converter located downstream of the electric motor; a rotor input clutch selectively engageable and disengageable to drivingly connect or disconnect the rotor from an output of an engine crankshaft, the rotor input clutch comprising a piston and at least one clutch plate, the piston configured to be pressed into the at least one clutch plate in a first axial direction to engage the rotor input clutch via a pressure increase of a fluid in an apply chamber; as well as a compensation chamber assembly, the compensation chamber assembly and the piston defining a compensation chamber radially offset from the apply chamber, the compensation chamber assembly configured to apply a force to the piston in a second axial direction opposite the first axial direction via a pressure increase of a fluid in the compensation chamber; Wherein, the compensation chamber assembly includes a second compensation part, the second compensation part defines a fluid reservoir located radially inside the compensation chamber, the fluid reservoir is used to pressurize the fluid to the compensation chamber through rotation of the compensation chamber assembly and the piston, the application chamber is formed by the second compensation part and the piston, the second compensation part includes a channel extending radially outward from the reservoir through the second compensation part, and the channel is configured to supply fluid from the fluid reservoir to the compensation chamber via a channel in the piston.

2. The hybrid module according to claim 1, wherein: The compensation chamber assembly includes a first compensation portion located radially outward of a location where the piston is configured to contact the at least one clutch plate.

3. The hybrid module according to claim 2, wherein: The first compensating portion is sealed relative to the piston by at least one seal to define the compensating chamber, and the piston is axially slidable relative to the first compensating portion along the at least one seal.

4. The hybrid module according to claim 2, wherein: The first compensation portion includes a radially inner narrower section and a radially outer wider section, and an inner peripheral surface of the radially outer wider section and a radially extending surface of the radially inner narrower section define the compensation chamber having the piston.

5. The hybrid module according to claim 1, wherein: The second compensating portion includes a first plate segment and a second plate segment, the reservoir being axially defined between the first plate segment and the second plate segment.

6. The hybrid module according to claim 1, wherein: The second compensating portion comprises a channel through the second compensating portion for supplying fluid to the application chamber.

7. The hybrid module according to claim 1, further comprising: a rotor carrier non-rotatably fixed to the rotor; and a rotor flange non-rotatably fixed to and extending radially inwardly from the rotor carrier, the piston being configured to press the at least one clutch plate into the rotor flange to engage the rotor input clutch.

8. The hybrid power module according to claim 1, wherein: The torque converter is located radially inside the rotor.

9. The hybrid module of claim 8 further comprising a rotor output clutch that is selectively engageable and disengageable such that the rotor drivingly transmits torque to the turbine hub via fluid flow from the torque converter when the rotor output clutch is disengaged and bypasses the fluid flow from the torque converter when the rotor output clutch is engaged.

10. A method of configuring a hybrid module configured for placement in a torque path upstream of a transmission and downstream of an internal combustion engine, the method comprising: An electric motor is provided comprising a rotor and a stator for driving the rotor; A torque converter is provided downstream of the electric motor; drivingly coupling an output of a rotor input clutch to the rotor, the rotor input clutch being selectively engageable and disengageable to drivingly connect the rotor to or disconnect the rotor from an output of an engine crankshaft, the rotor input clutch comprising a piston and at least one clutch plate, the piston being configured to be pressed into the at least one clutch plate in a first axial direction to engage the rotor input clutch via a pressure increase of a fluid in an apply chamber; as well as A compensation chamber assembly is provided on the piston, the compensation chamber assembly and the piston defining a compensation chamber radially offset from the application chamber, the compensation chamber assembly being configured to apply a force to the piston in a second axial direction opposite to the first axial direction via a pressure increase of a fluid in the compensation chamber, The compensation chamber assembly includes: a first compensation portion, which is located radially outside the position where the piston is configured to contact the at least one clutch plate; and a second compensation portion, which defines a fluid reservoir radially inside the compensation chamber, and the fluid reservoir is used to pressurize the fluid to the compensation chamber through the rotation of the compensation chamber assembly and the piston, and the application chamber is formed by the second compensation portion and the piston.

11. The method according to claim 10, wherein: The torque converter is located radially inwardly of the rotor, and the method further includes providing a rotor output clutch that is selectively engageable and disengageable, such that the rotor drivingly transmits torque to the turbine hub via a fluid flow through the torque converter when the rotor output clutch is disengaged, and bypasses the fluid flow through the torque converter when the rotor output clutch is engaged.

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