Four wheel steer control system connected with limited slip differential

• US 4,716,982 A
• Filed: 11/12/1986
• Issued: 01/05/1988
• Est. Priority Date: 11/13/1985
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Hirayama, Kanae, Takahashi, Kotei, Ishii, Katsumi, Matsuoka, Yoshio
• Primary Examiner(s): Pekar, John A.
• Application Number:
  US06/929,276
• Time in Patent Office: 419 Days
• Field of Search: 180/140, 180/233, 180/244, 180/247, 280/91, 364/424
• US Class Current: 180/415
• CPC Class Codes: B60K 23/04 for differential gearing
• CPC Class Codes: B62D 7/1536 provided with hydraulic assistance
• CPC Class Codes: B62D 7/1545 provided with electrical assistance

Abstract

A four wheel steer control system includes a four wheel steer system, a differential between right and left driving wheels, a slip limiting system for limiting a differential action of the differential with a slip limiting resistive force whose magnitude is varied in accordance with a vehicle speed or other variable, a sensor for sensing the magnitude of the slip limiting resistive force, and a controller for controlling a ratio of a rear wheel steer angle to a steering wheel angle in accordance with the magnitude of the slip limiting resistive force.

Claims

1. A vehicle comprising;

a four wheel steer system for varying a rear wheel steer angle in response to a control signal,

a differential disposed between right and left drive wheels of said vehicle,

slip limiting means for limiting a differential action of said differential,

means for sensing a slip limiting amount of said slip limiting means, and

controlling means for producing said control signal and controlling a ratio of the rear wheel steer angle to a steering wheel angle in accordance with said slip limiting amount sensed by slip limiting amount sensing means.

2. A vehicle according to claim 1 wherein said controlling means comprises means for increasing said ratio when slip limiting amount decreases, and for decreasing said ratio when slip limiting amount increases.

3. A vehicle according to claim 1 wherein said controlling means comprises means for varying said ratio in accordance with slip limiting amount only when vehicle speed is higher than a predetermined speed.

4. A vehicle according to claim 3 where said controlling means comprises means for controlling said slip limiting means to vary slip limiting amount in accordance with vehicle speed.

5. A vehicle according to claim 4 wherein said controlling means comprises means for controlling said slip limiting means to increase slip limiting amount when vehicle speed increases.

6. A vehicle according to claim 5 wherein said slip limiting means comprises a friction clutch for limiting said differential action of said differential with a resistive force, and said slip limiting amount is a magnitude of said resistive force developed by said friction clutch.