Torque vectoring drive mechanism having a power sharing control system

• US 20050176543A1
• Filed: 01/26/2005
• Published: 08/11/2005
• Est. Priority Date: 02/21/2003
• Status: Active Grant

• Current Assignee: Magna Drivertrain of America Incorporated
• Original Assignee: Magna Drivertrain of America Incorporated
• Inventors: Bowen, Thomas C., Kirkwood, Malcolm E.
• Granted Patent: US 7,211,019 B2
• Time in Patent Office: Days
• US Class Current: 475/5
• CPC Class Codes: B60K 17/35 including arrangements for suppressing or influencing the power transfer, e.g. viscous clutches differential gearing with locking devices F16H48/20
• CPC Class Codes: B60K 23/0808 for varying torque distribution between driven axles, e.g. by transfer clutch
• CPC Class Codes: F16H 48/10 with orbital spur gears

Abstract

A torque transfer mechanism is provided for controlling the magnitude of a clutch engagement force exerted on a multi-plate clutch assembly that is operably disposed between a first rotary and a second rotary member. The torque transfer mechanism includes a clutch actuator assembly for generating and applying a clutch engagement force on the clutch assembly. The clutch actuator assembly includes an electric motor/brake unit and a torque/force conversion mechanism. The motor/brake unit can be operated in either of a motor mode or a brake mode to cause bi-directional linear movement of an output member of the torque/force conversion mechanism. The thrust force generated by the torque/force conversion mechanism is applied to the clutch assembly. The dual mode feature of the electric motor/brake unit significantly reduces the power requirements. A torque vectoring drive axle is equipped with a pair of such torque transfer mechanisms.

Claims

1. A drive axle assembly for use in a motor vehicle having a powertrain and first and second wheels, comprising;

an input shaft driven by the powertrain;

a first axleshaft driving the first wheel;

a second axleshaft driving the second wheel;

a differential having an input component driven by said input shaft, a first output component driving said first axleshaft and a second output component driving said second axleshaft;

a first speed changing unit having a first sun gear driven by said first output component, a first ring gear, and a set of first planet gears meshed with said first sun gear and said first ring gear;

a second speed changing unit having a second sun gear driven by said second output component, a second ring gear, and a set of second planet gears meshed with said second sun gear and said second ring gear;

a first clutch selectively engageable to brake rotation of said first ring gear;

a first clutch actuator for controlling engagement of said first clutch by shifting a first electric motor between a motor mode and a brake mode;

a second clutch selectively engageable to brake rotation of said second ring gear;

a second clutch actuator for controlling engagement of said second clutch by shifting a second electric motor between a motor mode and a brake mode; and

a control system for selectively switching said first and second electric motors between their respective motor and brake modes.

2. The drive axle assembly of claim 1 wherein said first electric motor is operable in each of its motor and brake modes for generating an output torque that is converted by a first conversion mechanism into a clutch engagement force applied to said first clutch, and wherein said first motor is operable in its brake mode to regenerate electrical power that can be used by said control system to selectively actuate said second clutch actuator.

3. The drive axle assembly of claim 2 wherein said control system provides electrical power to drive said first motor when operating in its motor mode, and wherein said control system extracts electrical power to brake said first motor when operating in its brake mode.

4. The drive axle assembly of claim 2 wherein said first conversion mechanism includes first and second components with said first component adapted to move axially in response to relative rotation between said first and second components for applying said clutch engagement force to said first clutch, wherein said first electric motor includes a first rotor that is fixed for rotation with said second component of said first conversion mechanism, and wherein said first motor is operable in its motor mode to drive said first rotor so as to cause relative rotation between said first and second components and is further operable in its brake mode to brake rotation of said first rotor so as to cause relative rotation between said first and second components.

5. The drive axle assembly of claim 4 wherein said a second electric motor is operable in each of its motor and brake modes for generating an output torque that is converted by a second conversion mechanism into a clutch engagement force applied to said second clutch, and wherein said second motor is operable in its brake mode to regenerate electrical power used by said control system to selectively actuate said first electric motor.

6. The drive axle assembly of claim 5 wherein said second conversion mechanism includes first and second components with said first component adapted to move axially in response to relative rotation between said first and second components for applying said clutch engagement force to said second clutch, wherein said second electric motor includes a second rotor that is fixed for rotation with said second component of said second conversion mechanism, and wherein said second motor is operable in its motor mode to drive said second rotor so as to cause relative rotation between said first and second components and is further operable in its brake mode to brake rotation of said second rotor so as to cause relative rotation between said first and second components.

7. The drive axle assembly of claim 1 wherein a first drive mode is established when said first clutch is engaged and said second clutch is released, whereby said first axleshaft is overdriven relative to said input component and said differential causes said second axleshaft to be underdriven relative to said input component;

and wherein a second drive mode is established when said first clutch is released and said second clutch is engaged, whereby said second axleshaft is overdriven relative to said input component and said differential causes said first axleshaft to be underdriven relative to said input component.

8. A drive axle assembly for use in a motor vehicle having a powertrain and first and second wheels, comprising:

an input shaft driven by the powertrain;

a first axleshaft driving the first wheel;

a second axleshaft driving the second wheel;

a differential having an input component driven by said input shaft and first and second output components;

a first speed changing unit having a first sun gear driving said first axleshaft, a ring gear driven by said first output component, and a set of first planet gears meshed with said first sun gear and said first ring gear;

a second speed changing unit having a second sun gear driving said second axleshaft, a second ring gear driven by said second output component, and a set of second planet gears meshed with said second sun gear and said second ring gear;

a first clutch selectively engageable to brake rotation of said first ring gear;

a first clutch actuator for controlling engagement of said first clutch by shifting a first electric motor between a motor mode and a brake mode;

a second clutch selectively engageable to brake rotation of said second ring gear;

a second clutch actuator for controlling engagement of said second clutch by shifting a second electric motor between a motor mode and a brake mode; and

a control system for controlling actuation of said first and second electric motors.

9. The drive axle assembly of claim 8 wherein said first electric motor is operable in each of its motor and brake modes for generating an output torque that is converted by a first conversion mechanism into a clutch engagement force applied to said first clutch, and wherein said first motor is operable in its brake mode to regenerate electrical power that can be used by said control system to selectively actuate said second clutch actuator.

10. The drive axle assembly of claim 9 wherein said control system provides electrical power to drive said first motor when operating in its motor mode, and wherein said control system extracts electrical power to brake said first motor when operating in its brake mode.

11. The drive axle assembly of claim 9 wherein said first conversion mechanism includes first and second components with said first component adapted to move axially in response to relative rotation between said first and second components for applying said clutch engagement force to said first clutch, wherein said first electric motor includes a first rotor that is fixed for rotation with said second component of said first conversion mechanism, and wherein said first motor is operable in its motor mode to drive said first rotor so as to cause relative rotation between said first and second components and is further operable in its brake mode to brake rotation of said first rotor so as to cause relative rotation between said first and second components.

12. The drive axle assembly of claim 11 wherein said a second electric motor is operable in each of its motor and brake modes for generating an output torque that is converted by a second conversion mechanism into a clutch engagement force applied to said second clutch, and wherein said second motor is operable in its brake mode to regenerate electrical power used by said control system to selectively actuate said first electric motor.

13. The drive axle assembly of claim 12 wherein said second conversion mechanism includes first and second components with said first component adapted to move axially in response to relative rotation between said first and second components for applying said clutch engagement force to said second clutch, wherein said second electric motor includes a second rotor that is fixed for rotation with said second component of said second conversion mechanism, and wherein said second motor is operable in its motor mode to drive said second rotor so as to cause relative rotation between said first and second components and is further operable in its brake mode to brake rotation of said second rotor so as to cause relative rotation between said first and second components.

14. The drive axle assembly of claim 8 wherein a first drive mode is established when said first clutch is engaged and said second clutch is released, whereby said first axleshaft is overdriven relative to said input component and said differential causes said second axleshaft to be underdriven relative to said input component, and wherein a second drive mode is established when said first clutch is released and said second clutch is engaged, whereby said second axleshaft is overdriven relative to said input component and said differential causes said first axleshaft to be underdriven relative to said input component.

15. A drive axle assembly for use in a motor vehicle having a powertrain and first and second wheels, comprising:

an input shaft driven by the powertrain;

a first axleshaft driving the first wheel;

a second axleshaft driving the second wheel;

a differential having an input component driven by said input shaft, a first output component driving said first axleshaft and a second output component driving said second axleshaft;

a first gearset having a first ring gear driven by said input component, a first sun gear, a first planet carrier driven by said first output component, and a set of first planet gears supported by said first planet carrier and meshed with said first sun gear and said first ring gear;

a second gearset having a second ring gear driven by said input component, a second sun gear, a second planet carrier driven by said second output component, and a set of second planet gears supported by said second planet carrier and meshed with said second sun gear and said second ring gear;

a first clutch selectively engageable to brake rotation of said first sun gear;

a first clutch actuator including a first electric motor that is operable in a motor mode and a brake mode to control engagement of said first clutch;

a second clutch selectively engageable to brake rotation of said second sun gear;

a second clutch actuator including a second electric motor that is operable in a motor mode and a brake mode to control engagement of said second clutch; and

a control system for controlling actuation of said first and second electric motors.

16. The drive axle assembly of claim 15 wherein said first electric motor is operable in each of its motor and brake modes for generating an output torque that is converted by a first conversion mechanism into a clutch engagement force applied to said first clutch, and wherein said first motor is operable in its brake mode to regenerate electrical power that can be used by said control system to selectively actuate said second clutch actuator.

17. The drive axle assembly of claim 16 wherein said control system provides electrical power to drive said first motor when operating in its motor mode, and wherein said control system extracts electrical power to brake said first motor when operating in its brake mode.

18. The drive axle assembly of claim 16 wherein said first conversion mechanism includes first and second components with said first component adapted to move axially in response to relative rotation between said first and second components for applying said clutch engagement force to said first clutch, wherein said first electric motor includes a first rotor that is fixed for rotation with said second component of said first conversion mechanism, and wherein said first motor is operable in its motor mode to drive said first rotor so as to cause relative rotation between said first and second components and is further operable in its brake mode to brake rotation of said first rotor so as to cause relative rotation between said first and second components.

19. The drive axle assembly of claim 18 wherein said a second electric motor is operable in each of its motor and brake modes for generating an output torque that is converted by a second conversion mechanism into a clutch engagement force applied to said second clutch, and wherein said second motor is operable in its brake mode to regenerate electrical power used by said control system to selectively actuate said first electric motor.

20. The drive axle assembly of claim 19 wherein said second conversion mechanism includes first and second components with said first component adapted to move axially in response to relative rotation between said first and second components for applying said clutch engagement force to said second clutch, wherein said second electric motor includes a second rotor that is fixed for rotation with said second component of said second conversion mechanism, and wherein said second motor is operable in its motor mode to drive said second rotor so as to cause relative rotation between said first and second components and is further operable in its brake mode to brake rotation of said second rotor so as to cause relative rotation between said first and second components.

21. The drive axle assembly of claim 15 wherein a first drive mode is established when said first clutch is engaged and said second clutch is released, whereby said first axleshaft is underdriven relative to said input component and said differential causes said second axleshaft to be overdriven relative to said input component, and wherein a second drive mode is established when said first clutch is released and said second clutch is engaged, whereby said second axleshaft is underdriven relative to said input component and said differential causes said first axleshaft to be overdriven relative to said input component.

22. A drive axle assembly for use in a motor vehicle having a powertrain and first and second wheels, comprising:

an input shaft driven by the powertrain;

a first axleshaft driving the first wheel;

a second axleshaft driving the second wheel;

a differential assembly having an input component driven by said input shaft, a first output component fixed for rotation with said first axleshaft, and a second output component fixed for rotation with said second axleshaft;

a first gearset having a first sun gear, a first ring gear, a first planet carrier fixed for rotation with one of said input component and said second output component of said differential, and first planet gears rotatably supported by said first planet carrier and meshed with said first sun gear and said first ring gear;

a second gearset having a second sun gear, a second ring gear fixed for rotation with said first planet carrier, a second planet carrier fixed for rotation with said first axleshaft, and second planet gears rotatably supported by said second planet carrier and meshed with said second sun gear and said second ring gear;

a first clutch for selectively braking rotation of said first sun gear;

a first clutch actuator for controlling engagement of said first clutch and including a first electric motor operable in a motor mode and a brake mode;

a second clutch for selectively inhibiting rotation of said second sun gear;

a second clutch actuator for controlling engagement of said second clutch and including a second electric motor operable in a motor mode and a brake mode; and

a control system for controlling actuation of said first and second electric motors between their respective motor and brake modes.

23. The drive axle assembly of claim 22 wherein said first electric motor is operable in each of its motor and brake modes for generating an output torque that is converted by a first conversion mechanism into a clutch engagement force applied to said first clutch, and wherein said first motor is operable in its brake mode to regenerate electrical power that can be used by said control system to selectively actuate said second clutch actuator.

24. The drive axle assembly of claim 23 wherein said control system provides electrical power to drive said first motor when operating in its motor mode, and wherein said control system extracts electrical power to brake said first motor when operating in its brake mode.

25. The drive axle assembly of claim 23 wherein said first conversion mechanism includes first and second components with said first component adapted to move axially in response to relative rotation between said first and second components for applying said clutch engagement force to said first clutch, wherein said first electric motor includes a first rotor that is fixed for rotation with said second component of said first conversion mechanism, and wherein said first motor is operable in its motor mode to drive said first rotor so as to cause relative rotation between said first and second components and is further operable in its brake mode to brake rotation of said first rotor so as to cause relative rotation between said first and second components.

26. The drive axle assembly of claim 25 wherein said a second electric motor is operable in each of its motor and brake modes for generating an output torque that is converted by a second conversion mechanism into a clutch engagement force applied to said second clutch, and wherein said second motor is operable in its brake mode to regenerate electrical power used by said control system to selectively actuate said first electric motor.

27. The drive axle assembly of claim 26 wherein said second conversion mechanism includes first and second components with said first component adapted to move axially in response to relative rotation between said first and second components for applying said clutch engagement force to said second clutch, wherein said second electric motor includes a second rotor that is fixed for rotation with said second component of said second conversion mechanism, and wherein said second motor is operable in its motor mode to drive said second rotor so as to cause relative rotation between said first and second components and is further operable in its brake mode to brake rotation of said second rotor so as to cause relative rotation between said first and second components.

28. The drive axle assembly of claim 22 wherein said first clutch is operable in a first mode to permit unrestricted rotation of said first sun gear and in a second mode to prevent rotation of said first sun gear, wherein said second clutch is operable in a first mode to permit unrestricted rotation of said second sun gear and in a second mode to prevent rotation of said second sun gear.

29. The drive axle assembly of claim 28 wherein an overdrive mode is established when said first clutch is in its second mode and said second clutch is in its first mode such that said first axleshaft is driven at an increased rotary speed relative to said input component which causes said second axleshaft to be driven at a decreased rotary speed relative to said input component.

30. The drive axle assembly of claim 28 wherein an underdrive mode is established when said first clutch is in its first mode and said second cutch is in its second mode such that said first axleshaft is 8 driven at a reduced rotary speed relative to said input component which causes said second axleshaft to be driven at a corresponding increased rotary speed.