The present disclosure relates to electric drive systems for motor vehicles. More specifically, the present disclosure relates to a two-speed electric drive module for electric and hybrid vehicles.
Automobile manufacturers are actively working to develop alternative powertrain systems in an effort to reduce the level of pollutants exhausted into the air by conventional vehicles equipped with internal combustion engines. Significant development has been directed to electric vehicles and fuel cell vehicles. These alternative powertrain systems are still under development. In addition, several different hybrid electric vehicles have recently been offered for sale. These hybrid vehicles are equipped with an internal combustion engine and an electric motor that can be operated independently or in combination to drive the vehicle.
There are two typical types of hybrid vehicles, namely, series hybrid and parallel hybrid. In a series hybrid vehicle, power is delivered to the wheels by the electric motor which draws electrical energy from the battery. The engine is used in series hybrid vehicles to drive a generator which supplies power directly to the electric motor or charges the battery when the state of charge falls below a predetermined value. In parallel hybrid vehicles, the electric motor and the engine can be operated independently or in combination pursuant to the running conditions of the vehicle. Typically, the control strategy for such parallel hybrid vehicles utilizes a low-load mode where only the electric motor is used to drive the vehicle, a high-load mode where only the engine is used to drive the vehicle, and an intermediate assist mode where the engine and electric motor are both used to drive the vehicle. Regardless of the type of hybrid drive system used, hybrid vehicles are highly modified versions of conventional vehicles that are expensive due to the componentry, required control systems, and specialized packaging requirements.
Hybrid powertrains have also been adapted for use in four-wheel drive vehicles and typically utilize the above-noted parallel hybrid powertrain to drive the primary wheels and a second electric motor to drive the secondary wheels. Obviously, such a four-wheel drive system is extremely expensive and difficult to package. Thus, a need exists to develop solely electrically powered or hybrid powertrains for use in four-wheel drive vehicles that utilize many conventional powertrain components so as to minimize specialized packaging and reduce cost.
An electric drive module for a motor vehicle includes an electric motor, a first input member, a first output member and a two-speed module selectively drivingly interconnecting the first input member and the first output member at one of two different drive ratios. A reduction unit includes a second input member being driven by the first output member and has a second output member being driven at a reduced speed relative to the second input member. A differential assembly has an input driven by said second output member. A first differential output drives a first output shaft, and a second differential output drives a second output shaft.
Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present disclosure, are intended for purposes of illustration only since various changes and modifications within the fair scope of this particular disclosure will become apparent to those skilled in the art.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
The present disclosure is related to an electric drive module assembly including an electric motor. The electric drive module is electrically-controlled for delivering motive power (i.e., drive torque) to a pair of ground-engaging wheels. The compact arrangement of the electric motor, a single speed gearbox and an optional two-speed module permits the use of the electric drive module in substitution for a conventional axle assembly. As such, conventional rear-wheel drive and front-wheel drive powertrains can be used in combination with the electric drive module so as to establish a hybrid drive system for a four-wheel drive vehicle. Alternatively, the electric drive module may be used in vehicles powered solely by batteries as well. Accordingly, various features and functional characteristics of the electric drive module will be set forth below in a manner permitting those skilled in relevant arts to fully comprehend and appreciate the significant advantages the present disclosure provides.
Referring to
In the particular layout shown in
As shown in
Referring now to
Electric drive module 32 further includes a gearbox 68 located within gearbox chamber 46 and which is comprised of a reduction unit 70 and a bevel differential 72. Reduction unit 70 includes a first reduction gearset 74 having a first drive gear 76 in constant meshed engagement with a first driven gear 78 as well as a second reduction gearset 80 having a second drive gear 82 in constant meshed engagement with a second driven gear 84. First drive gear 76 is fixed for rotation with a transfer shaft 86 providing power from two-speed drive module 50. First driven gear 78 and second drive gear 82 are fixed for rotation with a countershaft 88 rotatably supported by bearings 90. First drive gear 76 is fixed via a spline connection 92 for rotation with transfer shaft 86 while second driven gear 84 is fixed to a casing 94 of bevel differential 72. Thrust bearings 96 and 98 are provided on either side of first drive gear 76. Other bearing arrangements are possible.
With reference to
A parking pawl assembly 130 is provided to selectively ground a parking gear 132 integrally formed with first drive gear 76 to housing 42. Parking gear 132 includes a plurality of teeth 134 selectively engageable with a parking pawl 136 rotatably positioned on a pawl shaft 138. When parking pawl 136 is engaged with teeth 134, rotation of the components within reduction unit 70 is restricted. Accordingly, movement of vehicle 10 is also restricted. Parking pawl 136 may be rotatably displaced about pawl shaft 138 to become disengaged from teeth 134 to allow rotation of the components within reduction unit 70 as previously described.
In accordance with a use of electric drive module 32, output shafts 112 and 118 are adapted to be connected to corresponding ones of front axleshafts 36 and 40 for the hybrid powertrain arrangement shown in
It should be appreciated that electric drive module 32 may be configured as a single speed power transmission device as shown in
Referring once again to the two-speed arrangement, as best depicted in
First clutch 142 includes a drum 180 fixed to annulus gear 148 via a spline 182. A hub 184 of first clutch 142 includes a radially inwardly positioned collar 186 fixed for rotation with concentric shaft 162 and sun gear 156 via a spline connection 188. Hub 184 also includes a radially outwardly positioned cylindrical portion 190 integrally formed with collar 186 and radially extending webs 192.
First clutch 142 also includes a plurality of outer clutch plates 194 fixed for rotation with and axially moveable relative to drum 180 via a spline connection 196. A plurality of inner clutch plates 198 are fixed for rotation with and axially moveable relative to cylindrical portion 190. Outer clutch plates 194 are interleaved with inner clutch plates 198. Outer clutch plates 194 and inner clutch plates 198 of first clutch 142 are bounded by a flange 199 integrally formed as a portion of hub 184 and a reaction plate 200 that is restricted from axial movement in one direction by a snap ring 201 coupled to drum 180.
A load plate 202 is supported on concentric shaft 162 and restricted from axial motion relative thereto by a flange 204 and a snap ring 206. A thrust bearing 208 is positioned between carrier 158 and load plate 202. A spring 210 urges hub 184 away from load plate 202 and relative to drum 180. Spring 210 biases hub 184 toward a first position where flange 199 applies a compressive force to outer clutch plates 194 and inner clutch plates 198 to transfer torque through first clutch 142.
Second clutch 144 includes a plurality of inner clutch plates 250 fixed for rotation with hub 184 at cylindrical portion 190. A plurality of outer clutch plates 252 are interleaved with inner clutch plates 250 and fixed to case 52. A reaction plate 254 is also fixed to case 52. An actuator plate 256 is positioned on the opposite side of reaction plate 254 to capture inner clutch plates 250 and outer clutch plates 252 therebetween. Actuator plate 256 may be integrally formed with or drivingly coupled to a first cam plate 260 of actuator 146.
Actuator 146 is depicted as a ball ramp actuator including an axially moveable first cam plate 260 cooperating with a rotatable second cam plate 262. First cam plate 260 is restricted from rotation and second cam plate 262 is restricted from translation. Cam plates 260 and 262 each include tapered circumferentially extending grooves 264 and 266, respectively. A ball 268 is positioned within cam grooves 264, 266. Because the cam grooves are tapered, relative rotation between second cam plate 262 and first cam plate 260 induces axial movement of first cam plate 260 relative to second cam plate 262. A thrust bearing 272 is positioned between second cam plate 262 and case 52 to react the axial load generated by actuator 146. Cam plate 262 also includes a plurality of gear teeth 274 formed on an outer circumferential surface.
An actuator gear 276 is in constant meshed engagement with gear teeth 274. An input spindle 278 is integrally formed with actuator gear 276. A source of torque such as an electric motor 280 is drivingly coupled to input spindle 278. Electric motor 280 may be controlled to rotate input spindle 278 in either direction. As such, second cam plate 262 may be rotated in either direction to move first cam plate 260 axially relative thereto. First cam plate 260 is moveable between a first position closest to second cam plate 262 and a second position furthest from second cam plate 262. Spring 210 urges hub 184 and first cam plate 260 toward the first position via a thrust bearing 290. When first cam plate 260 is in the first position, actuator plate 256 is located at a retracted position and a load is not applied to inner clutch plates 250 or outer clutch plates 252. At this time, torque is not transferred through second clutch 144.
It should be appreciated that while clutch actuator 146 is depicted as an electric motor driven ball ramp actuator, other actuators capable of providing an axial apply force to actuator plate 256 and hub 184 are also contemplated. Specifically, a hydraulically powered piston, an electrical solenoid, an electrically powered linear actuator or the like may be incorporated in lieu of the geared ball ramp arrangement.
In operation, the actuation of electric motor assembly 58 causes concurrent rotation of hub 150 and annulus gear 148. If the LOW gear ratio is desired, such as during vehicle launch, electric motor 280 is actuated to rotate input spindle 278 and actuator gear 276. Counter rotation of second cam plate 262 drives first cam plate 260 axially to provide an input force to actuator plate 256 and transfer torque through second clutch 144. At this time, hub 184 and sun gear 156 are restricted from rotation relative to case 52. The axial translation of first cam plate 260 also causes hub 184 to axially translate. Flange 199 is disengaged from outer clutch plates 194 and inner clutch plates 198 such that torque is not transferred through first clutch 142. With first clutch 142 being in the open, non torque-transferring condition, drum 180 and annulus gear 148 may rotate relative to hub 184 and sun gear 156. Based on the specific geometries of the meshing gears, a speed reduction ratio is provided by planetary gearset 140 with annulus gear 148 being the input and carrier 158 being the output of planetary gearset 140.
Power is transferred from carrier 158 through transfer shaft 86, first reduction gearset 74, second reduction gearset 80 and bevel differential 72. Power is then transferred through pinions 120 to side gears 108 and 114 and ultimately to output shafts 112 and 118. Variable speed control of motor assembly 58 permits the torque delivered to the wheels to be variably controlled.
When operation of electric drive module 32 in the HIGH gear ratio is desired, electric motor 280 is energized to rotate actuator gear 276 in the opposite direction from that previously described. Second cam plate 262 is rotated relative to first cam plate 260 such that ball 268 moves toward deeper portions of grooves 264, 266. Spring 210 biases hub 184 and first cam plate 260 toward the first position. Actuator plate 256 no longer applies a compressive force and second clutch 144 no longer transfers torque. Flange 199 applies a compressive force to the clutch plates of first clutch 142 and torque is transferred therethrough. At this time, annulus gear 148 is fixed for rotation with sun gear 156 to place planetary gearset 140 in a locked or direct-drive mode. Two-speed drive module 50 does not provide gear reduction when planetary gearset 140 operates in the direct drive mode. The overall speed reduction ratio provided by electric drive module 32 is defined by first gearset 74, second gearset 80 and bevel differential 72. The HIGH drive ratio may also be achieved when no power is provided to electric motor 280. Spring 210 provides the necessary energy to transfer torque through first clutch 142.
As shown in
In relation to the two-speed arrangement, controller 292 is operable to control clutch actuator 146 and execute an upshift from LOW to HIGH or a downshift from HIGH to LOW, as desired.
Referring to
Dog clutch 144A includes an axially moveable sleeve 300 fixed for rotation with sun gear 156A via a spline connection 302. Spring 210A biases sleeve 300 toward the position depicted in the bottom of
To shift two-speed module 50A from LOW to HIGH, pressurized fluid is provided to a cavity 314 containing piston 146A. Translation of piston 146A causes an apply ring 316 to also be axially translated in the same direction. Apply ring 316 is supported by a bearing 318 journaled on sleeve 300. Concurrent translation of sleeve 300 occurs to disengage dog teeth 304 from dog teeth 306 thereby allowing sun gear 156A to rotate relative to case 52A. At approximately the same time, bulbous portion 312 applies a compressive force to first clutch 142A to fix annulus gear 148A and sun gear 156A for rotation with one another. As previously described, these actions place planetary gearset 140A in a direct drive mode.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
This application is a U.S. National Phase of PCT/US2009/062142 filed on Oct. 27, 2009 which claims the benefit of U.S. Provisional Application No. 61/112,339 filed Nov. 7, 2008. The entire disclosure of each of the above applications is incorporated herein by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US2009/062142 | 10/27/2009 | WO | 00 | 5/6/2011 |
Publishing Document | Publishing Date | Country | Kind |
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WO2010/053745 | 5/14/2010 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
613894 | Vaughan-Sherrin | Nov 1898 | A |
2225720 | Snow | Dec 1940 | A |
3153158 | Schmitter | Oct 1964 | A |
4362065 | Baratti | Dec 1982 | A |
4418777 | Stockton | Dec 1983 | A |
4501982 | McMinn | Feb 1985 | A |
4774857 | Heine et al. | Oct 1988 | A |
5104056 | Jannotta et al. | Apr 1992 | A |
5419406 | Kawamoto et al. | May 1995 | A |
5427196 | Yamaguchi et al. | Jun 1995 | A |
5554080 | Dangel | Sep 1996 | A |
5678646 | Fliege | Oct 1997 | A |
5713427 | Lutz et al. | Feb 1998 | A |
5735767 | Forsyth | Apr 1998 | A |
5743348 | Coppola et al. | Apr 1998 | A |
5751081 | Morikawa | May 1998 | A |
5919109 | Fleckenstein | Jul 1999 | A |
6022048 | Harshbarger et al. | Feb 2000 | A |
6022287 | Klemen et al. | Feb 2000 | A |
6571654 | Forsyth | Jun 2003 | B2 |
6595308 | Bowen | Jul 2003 | B2 |
6598691 | Mita et al. | Jul 2003 | B2 |
6604591 | Bowen et al. | Aug 2003 | B2 |
6743135 | Klemen et al. | Jun 2004 | B2 |
6864607 | Hashimoto | Mar 2005 | B2 |
6872161 | DiCarlo | Mar 2005 | B2 |
6892837 | Simmons et al. | May 2005 | B2 |
7129595 | Reed et al. | Oct 2006 | B2 |
7247117 | Forster | Jul 2007 | B2 |
7268451 | Hertz et al. | Sep 2007 | B2 |
7549940 | Kira et al. | Jun 2009 | B2 |
7586225 | Raszkowski et al. | Sep 2009 | B2 |
7624828 | Kozarekar | Dec 2009 | B2 |
7762366 | Janson | Jul 2010 | B2 |
20030094322 | Bowen | May 2003 | A1 |
20030203782 | Casey et al. | Oct 2003 | A1 |
20060058146 | Brissenden et al. | Mar 2006 | A1 |
20070087890 | Hamrin et al. | Apr 2007 | A1 |
20080004149 | Mohan et al. | Jan 2008 | A1 |
20080058145 | Holmes | Mar 2008 | A1 |
20080182693 | Holmes | Jul 2008 | A1 |
20090188732 | Janson | Jul 2009 | A1 |
20090211824 | Knoblauch et al. | Aug 2009 | A1 |
Number | Date | Country |
---|---|---|
WO 2008034520 | Mar 2008 | WO |
Number | Date | Country | |
---|---|---|---|
20110218070 A1 | Sep 2011 | US |
Number | Date | Country | |
---|---|---|---|
61112339 | Nov 2008 | US |