Modular powertrain component for hybrid electric vehicles

Abstract

Powertrain module (10) comprising the following: an entrance (16); a first partition wall (32) supporting the entrance; a rotor hub (40); an electric machine (28) comprising a stator (30) connected to the first partition (60) and a rotor (34) connected to the rotor hub (40); a coupling (22) for alternately opening and closing a drive connection between the input (16) and the rotor hub (40); a power amplifier which is supported on the input (16) for actuating the clutch (22); a second partition (60) that supports the rotor hub (40); a flexplate (42) connected to the rotor hub (40) for drive and connectable to a torque converter housing (48); first wedge teeth formed on the rotor hub (40); and Second wedge teeth formed on the flexplate (42) which can engage with the first wedge teeth.

Description

[0001] The present invention relates to a powertrain module that can be installed between and attached to an engine output and a transmission input.

[0002] Hybrid electric vehicles (HEVs) have both an internal combustion engine and an electric motor, which can be used alternately or together to propel the vehicle. Hybrid vehicles utilize a variety of powertrains, such as a parallel configuration, where the engine is connected to the motor by a clutch, with the motor driving the torque converter input of an automatic hydraulic transmission. The hydraulic transmission has an output connected to a differential coupled to the vehicle's two driven wheels.

[0003] There is a need in the industry for a hybrid electric powertrain that includes a modular subassembly for use with a wide variety of engines and transmissions, such that the powertrain module can be installed and secured between an output of one of a plurality of engines and an input of one of a plurality of transmissions. The assembled powertrain can then be used in a wide variety of vehicles. The powertrain module should include a hydraulically actuated disconnect clutch, the electric machine, and suitable power paths between the engine and electric machine to the transmission input. Preferably, the powertrain module provides a hydraulic connection from the transmission hydraulic system to the clutch, a balance dam, and the electric machine.The powertrain module must provide an oil sump containing hydraulic fluid to be delivered to the powertrain module and a path for continuously returning the fluid to the transmission oil sump so that the transmission pump is continuously and reliably supplied with fluid.

[0004] The powertrain module should have low manufacturing and assembly costs, require no vehicle body modification, and provide reliable performance.

[0005] From US 2008 / 0 093 135 A1, a hybrid vehicle drive unit is known which includes an intermediate shaft, a starting clutch, and a motor generator. The motor generator includes a stator fixed to an inner part of a motor housing, which is fixed to a housing of the transmission, a rotor support member coupled to the clutch drum and having an inner end portion rotatably supported by an end wall of the motor housing, a rotor support portion mounted in an axial direction on an outer peripheral surface of the clutch drum such that play exists between the rotor support portion and the outer peripheral surface, and a rotor supported by the rotor support portion of the rotor support member and arranged such that an outer peripheral surface of the rotor opposes an inner peripheral surface of the stator.

[0006] DE 10 2011 109 702 A1 discloses a torque converter device for a motor vehicle, comprising at least one integrally formed housing element intended to drive-connect a torque converter and an internal combustion engine. The housing element forms at least one plate carrier for receiving at least one plate of a torque converter lock-up clutch.

[0007] Against this background, the object of the invention is to provide an improved drive train module.

[0008] This object is achieved by a drive train module having the features according to claim 1. The subclaims relate to embodiments.

[0009] A powertrain module includes an input, a first bulkhead supporting the input for rotation, a hub, an electric machine including a stator connected to the first bulkhead and a rotor connected to the hub, a clutch for alternately opening and closing a drive connection between the input and the rotor, a power amplifier for actuating the clutch and supporting the input, and a second bulkhead supporting the hub for rotation.

[0010] A torque converter housing can be driven by the engine alone, provided the electric machine is off and the clutch is engaged; by the electric machine alone, provided the engine is off or the engine is operating and the clutch is disengaged; and simultaneously by both the engine and the electric machine.

[0011] The scope of applicability of the preferred embodiment will become apparent from the following detailed description, claims, and drawings. It should be understood that the description and specific examples, while showing preferred embodiments of the invention, are for illustrative purposes only. Various changes and modifications to the described embodiments and examples will be apparent to those skilled in the art. DESCRIPTION OF THE DRAWINGS

[0012] The invention will be more easily understood by reference to the following description taken in conjunction with the accompanying drawings, in which: Fig. 1A and Fig. 1B may include a side cross-sectional view of a powertrain module showing a front connection to an engine output and a rear connection to a transmission torque converter input.

[0013] Fig. 1A and Fig. 1B show a powertrain module 10 of a powertrain for a hybrid electric vehicle, including an engine having a rotary output 12; a torsional damper 14 attached to the engine output 12; an input shaft 16 attached by a spline 18 to an output 20 of the torsional damper 14; a disconnect clutch 22 supported on a clutch hub 24 attached to the input shaft 16 by a spline 26; an electric machine 28 including a stator 30 bolted to a front bulkhead 32 as the first bulkhead and a rotor 34 supported by a first leg 36 and a second leg 38 for rotation about an axis 39; a rotor hub 40 attached, preferably by welding, to the second leg 38;and a flexplate 42 secured at one end to the rotor hub 40 by a spline connection 44 and at the opposite end by bolts 46 to a torque converter housing 48 enclosing a hydrokinetic torque converter 49. The electric machine 28 may be an electric motor or an electric motor-generator.

[0014] Torque converters suitable for use in the powertrain are listed in the Fig. 4a, Fig. 4b, Fig. 12 and Fig. 15 of U.S. Patent Application No. 13 / 325,101, filed December 14, 2011, the entire disclosure of which is hereby incorporated by reference.

[0015] The torque converter 49 includes a bladed impeller positioned within and secured to the housing 48; a bladed turbine hydrokinetically driven by the impeller and splined to the input shaft 52 of an automatic transmission 54; and a bladed stator wheel positioned between the turbine and the stator and secured to a stator shaft 56 that is non-rotatably supported on a transmission housing 58.

[0016] A rear partition 60 as a second partition, which is fastened to the gearbox housing 58 by screws 62, is provided on its radial inner surface with a hydraulic seal 64 which contacts the radial outer surface of the rotor hub 40.

[0017] A flywheel 66, which is fastened by screws 68 to the rotary output 12 of the engine, carries a starter ring gear 70, which is fastened by a disc 72 welded to the starter ring gear and the flywheel 66.

[0018] A bearing 74 supports the first leg 36 for rotation on the front bulkhead 32. A bearing 76 supports the second leg 38 for rotation on the rotor hub 40.

[0019] A tube 78 aligned with the axis 39 and supporting the windings of the rotor 34 for rotation about the axis is attached to the first leg 36 and the second leg 38. Lips 80, 82 at the front and rear ends of the tube 78, respectively, may be rolled radially outward to secure the rotor 34 to the tube 78 and prevent axial displacement of the rotor 34 relative to the tube. The inner surface of the tube 78 is formed with an axial spline 80 that is engaged by alternating plates 83 of the disconnect clutch 22. The friction plates 84 of the clutch 22 are secured by an axial spline formed on the radially outer surface of the clutch hub 24.

[0020] A hydraulic booster for actuating clutch 22 includes a piston 86, a reaction wall 88 (sometimes called a balance dam), a return spring 90, and hydraulic lines for transmitting actuating pressure to the pressure control volume 92 on the right side of piston 86 and to the pressure balance volume 94 on the left side of the piston. Piston 86 moves leftward within a cylinder defined by second leg 38 and rotor hub 40 when actuating pressure and hydraulic fluid are supplied to pressure control volume 92, causing clutch 22 to engage and driveably connect rotor 34 and engine output 12 through torsional damper 14, input shaft 16, clutch hub 24, and clutch 22.

[0021] Since the clutch hub 24 is fixed to the input shaft 16 by the spline 26 and the piston 86, the reaction wall 88 and the return spring 90 are supported on the clutch hub, the rotational inertia of the piston 86, the balance dam 88, the clutch hub 24 and the return spring 90 is on the input side, that is, the engine side, of the clutch 22.

[0022] The rotor 34 is continuously drivingly connected to the transmission input shaft 52 through the torque path including the second leg 38, the rotor hub 40, the flexplate 42, the torque converter housing 48, the hydrodynamic drive connection between the torque converter impeller and the turbine connected to the transmission input shaft 52.

[0023] A resolver 100, a high-precision type of electrical rotary transducer used to measure degrees of rotation, is attached to the front partition 32 by screws 102, is supported on the front partition 32 and the first leg 36, and is positioned axially between the front partition 32 and the rear partition 60.

[0024] The teeth of the spline 44, which creates a rotary drive connection between the flexplate 42 and the rotor hub 40, are fitted together so that no backlash is created when torque is transmitted between the flexplate and the rotor hub. The flexplate 42 is formed with a heavy-walled portion 104 having a threaded hole 106 terminating at a web 108. The outer spline teeth on the flexplate 42 are urged axially into engagement with the inner spline teeth on the rotor hub 40 by screws 110 that engage threaded holes in the right end of the rotor hub 40. The engaged spline teeth on the spline connection 44 are disengaged upon removal of the screws 110 and insertion of a larger screw into the hole 106 so that the screw contacts the web, thereby forcing the flexplate axially to the right.

[0025] The input shaft 16 is formed with an axially directed hydraulic passage that communicates with a laterally directed passage that carries hydraulic fluid and pressure from the hydraulic system of the transmission 54 to the powertrain module 10. The axial passage 120 and the lateral passage 122 carry hydraulic fluid and pressure to the pressure equalization volume 94 between the hub 24 and the piston 86. The axial passage 124 and the radial passage 126 carry hydraulic fluid and pressure to the clutch pressure control volume 92. The front bulkhead 32 is formed with a passage 128 that is in hydraulic communication with a variable force solenoid (VFS) 130. Other passages carry hydraulic fluid to the surfaces of the rotor 34 and the stator 30, which surfaces are cooled by the fluid.

[0026] The front bulkhead 32 supports a module sump 132 containing fluid supplied to the powertrain module 10 from the hydraulic system of the transmission 54. The transmission 54 includes a transmission sump 136 containing hydraulic fluid supplied to the transmission hydraulic system by a transmission pump 134, from which fluid and control pressure are supplied to the powertrain module 10, the torque converter 49, the transmission clutches and brakes, bearings, shafts, gears, etc.

[0027] A seal 140 mounted in the front bulkhead 32 and a bearing 142 mounted in the rotor hub 40 support the input shaft 16 during its rotation about the axis 39. The front bulkhead 32 further supports the stator 30 in its proper axial and radial position relative to the rotor 34.

[0028] The bearing 76 and bearing 142 mounted between the rear bulkhead 60 and the rotor hub 40 support the rotor hub 40 during its rotation about the axis 39. The front and rear bulkheads 32, 60 together support the rotor 34 during its rotation about the axis 39 through the bearing 74 mounted in the front bulkhead 32 and the bearing 76 mounted in the rear bulkhead 60.

[0029] The seal 64 mounted in the rear bulkhead 60 and the seal 140 mounted in the front bulkhead 32 prevent the passage of fluid from the powertrain module 10 positioned between the front and rear bulkheads 32, 60. Another dynamic seal 144 prevents the passage of contaminants between the engine compartment 146 and the powertrain module 10.

[0030] The components of the powertrain module 10 are installed and assembled within the powertrain module. The assembled powertrain module can then be installed between the engine output 12 and the torque converter housing 48.

[0031] In operation, when the engine output 12 is driven by an engine, torque is transferred from the engine through the rotor hub 40 and flexplate 42 to the torque converter housing 48, provided the clutch 22 is engaged. The rotor 34 of the electric machine 28 is continuously drivingly connected to the torque converter housing 48 through the tube 78, the second leg 38, the rotor hub 40, and the flexplate 42. Therefore, the torque converter housing 48 can be driven solely by the engine, provided the electric machine 28 is off and the clutch 22 is engaged; solely by the electric machine, provided the engine is off or the engine is operating and the clutch is disengaged; and simultaneously by both the engine and the electric machine.

[0032] The preferred embodiment has been described in accordance with the provisions of the patent statutes. However, it should be understood that alternative embodiments may be practiced otherwise than specifically illustrated and described.

Claims

[1] Powertrain module (10) comprising: an entrance (16); a first partition wall (32) supporting the entrance; a rotor hub (40); an electric machine (28) including a stator (30) connected to the first partition (60) and a rotor (34) connected to the rotor hub (40); a clutch (22) for alternately opening and closing a drive connection between the input (16) and the rotor hub (40); a power amplifier supported on the input (16) for actuating the clutch (22); a second partition wall (60) supporting the rotor hub (40); a flexplate (42) drive-connected to the rotor hub (40) and connectable to a torque converter housing (48); first spline teeth formed on the rotor hub (40); and second spline teeth formed on the flexplate (42) which can be brought into engagement with the first spline teeth. [2] The powertrain module (10) of claim 1, further comprising a torsional damper (14) connected to the input (16) and connectable to an engine output (12), the torsional damper (14) being positioned in a torque delivery path between the engine output (12) and the input (16). [3] The powertrain module (10) of claim 1, further comprising: a clutch hub (24) drive-connected to the input; a tube (78) attached to the rotor (34); a first leg (36) attached to the tube (78) and supported for rotation by a first bearing (74) on the first partition wall (32); a second leg (38) attached to the tube (78) and supported for rotation by a second bearing (76) on the second partition wall (60). [4] The powertrain module (10) of claim 3, further comprising a resolver (100) secured to the first partition wall (32) and the first leg (36) and positioned between the first (32) and second partition walls (60). [5] The powertrain module (10) of claim 3, further comprising a third bearing (142) mounted in the first partition wall (32) for supporting the input (16) during rotation. [6] The powertrain module (10) of claim 1, further comprising: a clutch hub (24) attached to the input (16); a tube (78) attached to the rotor (34); wherein the coupling (22) further comprises: first clutch plates attached to the clutch hub (24); and second coupling plates attached to the tube (78); and the power amplifier also contains: a piston (86) movable within a cylinder for urging the first and second clutch plates into mutual frictional engagement, thereby engaging the clutch (22); and a return spring (90) which urges the piston (86) away from the clutch plates, allowing the clutch plates to move apart and thus disengage the clutch (22). [7] Powertrain module (10) according to claim 6, further comprising: a clutch hub (24) drivingly connected to the input (16) and supporting the power amplifier; and Hydraulic lines formed in the input (16) and the clutch hub (24) and in hydraulic connection with the power booster. [8] The powertrain module (10) of claim 1, wherein the first partition wall (32) further includes: a module sump (132) for receiving hydraulic fluid; an electromagnetically operated valve (130); and a line (128) which is in hydraulic connection with the electromagnetically operated valve (130).

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