Rear wheel steering system for motor vehicle

• US 5,225,983 A
• Filed: 12/20/1990
• Issued: 07/06/1993
• Est. Priority Date: 12/21/1989
• Status: Expired due to Fees

• Current Assignee: Mazda Motor Corporation No 3-1 Shinchi Fuchu-Cho Aki-Gun Hiroshima-Ken Japan
• Original Assignee: Mazda Motor Corporation
• Inventors: Murai, Takeshi, Tomoda, Atuo, Nakashima, Takashi, Ohmura, Hiroshi, Kageyama, Fumio, Okazaki, Haruki, Edahiro, Takeshi, Akita, Ryuya
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/631,924
• Time in Patent Office: 929 Days
• Field of Search: 364/424.05, 364/426.02, 303/92, 303/96, 303/100, 180/197, 180/140, 180/141, 180/142, 180/79.1
• US Class Current: 701/48
• CPC Class Codes: B60T 2260/022 Rear-wheel steering; Four-wheel steering
• CPC Class Codes: B60T 2260/024 Yawing moment compensation during mu-split braking
• CPC Class Codes: B60T 2270/304 during driver brake actuation
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60T 8/4291 having means to reduce or eliminate pedal kick-back
• CPC Class Codes: B62D 7/159 characterised by computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition

Abstract

A rear steering control system for a motor vehicle includes an antiskid braking system which controls a braking force in a brake device in a respective wheel in accordance with a deceleration condition of the respective wheel so as to prevent wheel locking in a braking operation. The sytem includes a rear steering control system for establishing a ratio of steering amount of the rear wheels to that of the front wheels as a predetermined steering ratio characteristic. An input device inputs an operation condition of the antiskid braking system and an control condition of the brake device for the respective wheel conducted by the antiskid braking system to the rear steering control system. A device is provided in the system for amending the predetermined steering ratio characteristic in accordance with the control condition of the brake device for the respective wheel when the antiskid braking system is in operation.

Claims

1. A steering control system for a motor vehicle, including an antiskid braking system which controls a braking force in a brake device for a respective wheel in accordance with a deceleration condition of the respective wheel so as to prevent wheel locking in a braking operation, the system comprising:

a rear steering control system for establishing a ratio of a steering amount of the rear wheels to a steering amount of the front wheels as a predetermined steering ratio characteristic;

means for inputting signals representing an operation condition of the antiskid braking system and a control condition of the brake device for the respective wheel conducted by the antiskid braking system to the rear steering control system;

means for amending the predetermined steering ratio characteristic to a second steering ratio characteristic in accordance with the control condition of the brake device for the respective wheel when the antiskid braking system is in operation; and

means for sensing respective lock conditions of respective front and rear wheels;

wherein said means for amending the predetermined steering ratio characteristic amends the predetermined steering ratio characteristic to a third steering ratio characteristic which is positioned in a positive steering direction area relative to the predetermined steering ratio characteristic when said respective lock conditions of the respective front and rear wheels are substantially equal to each other, (b) the predetermined steering ratio characteristic to a fourth steering ratio characteristic which is positioned in said positive steering direction area relative to the predetermined steering ratio characteristic and in a negative steering direction area relative to the third steering ratio characteristic when the front wheels are locked earlier than the rear wheels, and (c) the predetermined steering ratio characteristic to a fifth steering ratio characteristic which is positioned in said positive steering direction area further from the third steering ratio characteristic when the rear wheels are locked earlier than the front wheels.

2. A rear steering control system in accordance with claim 1 in which said antiskid braking system controls the brake device in both the front and rear wheels independently.

3. A rear steering control system in accordance with claim 1 in which said rear steering control system is responsive to vehicle speed for establishing said predetermined steering ratio characteristic.