Rear wheel steering apparatus

• US 6,510,917 B2
• Filed: 03/28/2001
• Issued: 01/28/2003
• Est. Priority Date: 03/28/2001
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations Incorporated (General Motors Company), Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Cole, Michael James
• Primary Examiner(s): Lerner, Avraham
• Assistant Examiner(s): ROYAL, PAUL
• Application Number:
  US09/819,502
• Publication Number:
  US 20020140198A1
• Time in Patent Office: 671 Days
• Field of Search: 280/93.512, 180/414, 180/415, 180/417, 180/434, 180/436, 180/437
• US Class Current: 180/437
• CPC Class Codes: B60G 2200/314 with longitudinally arranged arms articulated on the axle
• CPC Class Codes: B60G 2200/44 steerable
• CPC Class Codes: B62D 5/0418 Electric motor acting on road wheel carriers
• CPC Class Codes: B62D 7/1581 characterised by comprising an electrical interconnecting system between the steering control means of the different axles

Abstract

A rear wheel steering apparatus for steering the rear wheels of a vehicle supported on a multi-link suspension includes a live axle and a track bar pivotally connecting the axle to a vehicle frame. Steering knuckles at opposite ends of the axle support road wheels for rotation and for steering. Steering arms extend from the steering knuckles and a drag link extends between and interconnects the steering arms. An actuator is connected between the frame and the drag link and steers the rear road wheels by alternately pushing and pulling on the drag link.

Claims

1. An apparatus for steering the rear wheels of a vehicle, the apparatus comprising:

a multi-link suspension including an axle and a track bar pivotally connecting the axle to a vehicle frame;

first and second steering knuckles supported at respective opposite ends of the axle and configured to support respective road wheels for rotation about respective generally horizontal road wheel rotational axes and for pivotal motion about respective generally vertical steering axes;

first and second steering arms extending generally horizontally from the respective first and second steering knuckles in a direction generally perpendicular to the respective steering axes;

a drag link extending between and interconnecting respective outer ends of the steering arms spaced from the respective steering knuckles; and

an actuator having a first end connected to the frame and a second end connected to the drag link, the actuator positioned and configured to pivot the roadwheels about their respective steering axes by alternately pushing and pulling on the drag link.

2. A rear wheel steering apparatus as defined in claim 1 in which the actuator is connected in parallel with the track bar, a first end of the actuator being connected to the frame at an actuator-frame connection point disposed adjacent a track bar-frame connection point.

3. A rear wheel steering apparatus as defined in claim 1 in which the actuator is a double-acting linear actuator.

4. A rear wheel steering apparatus as defined in claim 1 and further including:

a controller connected to the actuator; and

a handwheel position sensor connected to the controller and configured to sense handwheel steering inputs, the controller being configured to control the actuator to move the drag link in response to signal inputs from the handwheel position sensor.

5. A rear wheel steering apparatus as defined in claim 4 and further including a vehicle speed sensor connected to the controller and configured to sense vehicle speed, the controller configured to control the actuator to move the drag link in response to signal inputs from the vehicle speed sensor.

6. A rear wheel steering apparatus as defined in claim 4 and further including a front wheel angle sensor connected to the controller and configured to sense respective steering angles of front wheels of the vehicle, the controller configured to control the actuator to move the drag link in response to signal inputs from the front wheel angle sensor.

7. A rear wheel steering apparatus as defined in claim 3 in which a first end of the linear actuator is a body origin of the actuator.

8. A rear wheel steering apparatus as defined in claim 3 in which the linear actuator is configured and positioned to operate in parallel with the track bar.

9. A rear wheel steering apparatus as defined in claim 3 in which respective frame connection points of the actuator and track bar are at the same approximate point.

10. A rear wheel steering apparatus as defined in claim 3 in which the actuator and track bar are configured and positioned such that when the drag link and steering bars are in a position that does not angulate the rear wheels, the linear distance from the actuator-frame connection point to an actuator-drag link connection point is generally equal to the linear distance from the track bar-frame mounting point to a track bar-axle mounting point.

11. A rear wheel steering apparatus as defined in claim 10 in which the actuator and track bar are configured and positioned such that inequalities in the respective linear distances between actuator and track bar mounting points are small enough compared to track bar length, vertical axle travel and steering arm length, to preclude significant uncommanded steering inputs.

12. A rear wheel steering apparatus as defined in claim 4 in which the controller is configured to angulate the rear road wheels by an amount that decreases as the speed of the vehicle increases.

13. A rear wheel steering apparatus as defined in claim 4 in which the controller is configured to steer the rear road wheels out of phase with the front road wheels when the vehicle is traveling at less than a predetermined speed.

14. A rear wheel steering apparatus as defined in claim 4 in which the controller is configured to limit rear wheel steering to a maximum of half the steering angle of the front wheels.

15. A rear wheel steering apparatus as defined in claim 4 in which a vehicle attitude sensor is supported in the vehicle, is connected to the controller and is configured and positioned to detect vehicle attitude changes, the controller being configured to receive vehicle attitude signals from the vehicle attitude sensor and to command changes in actuator length to counter uncommanded steering inputs that the vehicle attitude changes would otherwise have caused.

16. An apparatus for steering the wheels of a vehicle having a multi-link suspension including an axle and a track bar pivotally connecting the axle to a vehicle frame, the apparatus comprising:

first and second steering knuckles supported at respective opposite ends of the axle and configured to support respective road wheels for rotation about respective generally horizontal road wheel rotational axes and for pivotal motion about respective generally vertical steering axes;

first and second steering arms extending generally horizontally from the respective first and second steering knuckles in a direction generally perpendicular to the respective steering axes;

a drag link extending between and interconnecting respective outer ends of the steering arms spaced from the respective steering knuckles;

an actuator having a second end connected to the drag link and configured to pivot the roadwheels by alternately pushing and pulling on the drag link; and

characterized by;

the actuator being connected in parallel with the track bar with a first end of the actuator connected to the vehicle frame to reduce the weight of the axle and to minimize ride steer.