Anti-skid control apparatus for a vehicle braking system

• US 4,793,662 A
• Filed: 02/17/1988
• Issued: 12/27/1988
• Est. Priority Date: 02/18/1987
• Status: Expired due to Term

• Current Assignee: Bosch Braking Systems Corporation (Robert Bosch GmbH)
• Original Assignee: Nippon ABS Ltd.
• Inventors: Arikawa, Tetsuro
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US07/157,323
• Time in Patent Office: 314 Days
• Field of Search: 303/91-119, 303/61-63, 303/68-69, 303/10-12, 303/DIGS. 1-4, 188/181 A, 188/181 C, 188/181 T, 188/181 R, 180/197, 180/244, 364/426
• US Class Current: 303/149
• CPC Class Codes: B60T 8/1764 Regulation during travel on surface with different coefficients of friction, e.g. between left and right sides, mu-split or between front and rear
• CPC Class Codes: B60T 8/346 2 Channel systems B60T8/345 takes precedence
• CPC Class Codes: B60T 8/94 on a fluid pressure regulator

Abstract

An anti-skid control apparatus for a vehicle braking system includes first and second fluid pressure control valve devices for controlling the brake fluid pressure of the wheel cylinders of the front and rear wheels each arranged between respective fluid pressure generating chamber of a tandem master cylinder and the associated wheel cylinder of the associated front or rear wheel; first and second wheel speed sensors associated with the front or rear wheels, respectively; and a third wheel speed sensor associated in common with the rear or front wheels. The control unit discriminates the frictionally lower one of the sides of the road on which the wheels are running, from the measuring or judging results of the skid conditions of the rear and front wheels, or of the front or rear wheels on the basis of the outputs of the first, second and third wheel speed sensors, or of the first and second wheel speed sensors, the low side being able to change over in accordance with said measuring or judging results at any time, combines logically the measuring or judging results of the skid conditions of the rear or front wheels with the measuring or judging result of the skid condition of the one front or rear wheel running on the low side for generating the instruction for controlling the first or second fluid pressure control valve device, and generates the instruction for controlling the second or first fluid pressure control valve device.

Claims

1. An anti-skid control apparatus for a vehicle braking system comprising:

(A) a pair front wheels, and a pair of rear wheels;

(B) a first fluid pressure control valve device for controlling the brake fluid pressure of the wheel cylinder of one of said front wheels, arranged between a first fluid pressure generating chamber of a tandem master cylinder and said wheel cylinder of the one front wheel;

(C) a second fluid pressure control valve device for controlling the brake fluid pressure of the wheel cylinder of another of said front wheels, arranged between a second fluid pressure generating chamber of said tandem master cylinder and said wheel cylinder of the other front wheel;

(D) a first path which transmits the brake fluid pressure controlled by said first fluid pressure control valve device, to the wheel cylinder of the one of said rear wheels connected diagonally to said one front wheel;

(E) a second path which transmits the brake fluid pressure controlled by said second fluid pressure control valve device, to the wheel cylinder of the other of said rear wheels connected diagonally to said other front wheel;

(F) first and second wheel speed sensors associated with said front wheels, respectively;

(G) a third wheel speed sensor associated in common with said rear wheels, and

(H) a control unit receiving outputs of said first, second and third wheel speed sensors for measuring or judging the skid conditions of said front and rear wheels and for generating instructions for controlling said first and second fluid pressure control valve devices;

wherein said control unit discriminates the frictionally lower one (designated as "low side") of the sides of the road on which said wheels are running, from the measuring or judging results of the skid conditions of said rear and front wheels, or of said front wheels on the basis of the outputs of said first, second and third wheel speed sensors, or of said first and second wheel speed sensors, said low side being able to change over in accordance with said measuring or judging results at any time, combines logically the measuring or judging results of the skid conditions of said rear wheels with the measuring or judging result of the skid condition of the one front wheel running on the low side for generating the instruction for controlling said first or second fluid pressure control valve device, and generates the instruction for controlling said second or first fluid pressure control valve device, on the basis of the measuring or judging result of the skid condition of the other front wheel running on the high side (frictionally higher side) independently of those of said rear wheels.

2. An anti-skid control apparatus according to claim 1, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one front wheel which generates said brake maintaining signal sooner than the other front wheel, is made "low side", before anyone of said front and rear wheels generates said brake relieving signal, or when the rear wheels generate said brake maintaining signal sooner than said front wheels both, the side of the one front wheel whose slip is more than the other front wheel'"'"'s slip, is made "low side".

3. An anti-skid control apparatus according to claim 1, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one front wheel which generates said brake relieving signal sooner than the other front wheel, is made "low side", or when the rear wheels generate said brake relieving signal sooner than said front wheels both, the side of the one front wheel whose slip is more than the other front wheel'"'"'s slip, is made "low side".

4. An anti-skid control apparatus according to claim 1, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one front wheel which generates said brake maintaining signal sooner than the other front wheel, is made "low side", before anyone of said front and rear wheels generates said brake relieving signal, or when the rear wheels generate said brake maintaining signal sooner than said front wheels both, the side of the one front wheel whose speed is lower than the other front wheel'"'"'s speed, is made "low side".

5. An anti-skid control apparatus according to claim 1, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one front wheel which generates said brake relieving signal sooner than the other front wheel, is made "low side", or when the rear wheels generate said brake relieving signal sooner than said front wheels both, the side of the one front wheel whose speed is lower than the other front wheel'"'"'s speed, is made "low side".

6. An anti-skid control apparatus according to claim 1, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one front wheel which generates said brake maintaining signal sooner than the other front wheel, is made "low side", before anyone of said front and rear wheels generates said brake relieving signal, or when the rear wheels generate said brake maintaining signal sooner than said front wheels both, the side of the one front wheel whose deceleration is lower than the other front wheel'"'"'s deceleration, is made "low side".

7. An anti-skid control apparatus according to claim 1, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one front wheel which generates said brake relieving signal sooner than the other front wheel, is made "low side", or when the rear wheels generate said brake relieving signal sooner than said front wheels both, the side of the one front wheel whose deceleration is more than the other front wheel'"'"'s deceleration, is made "low side".

8. An anti-skid control apparatus according to claim 1, in which a valve apparatus for generating a fluid pressure in accordance with the lower one of the brake fluid pressures of said front wheels controlled with said first and second fluid pressure control valve devices, is arranged between said first and second paths.

9. An anti-skid control apparatus for a vehicle braking system comprising:

(A) a pair front wheels, and a pair of rear wheels;

(B) a first fluid pressure control valve device for controlling the brake fluid pressure of the wheel cylinder of one of said rear wheels, arranged between a first fluid pressure generating chamber of a tandem master cylinder and said wheel cylinder of the one rear wheel;

(C) a second fluid pressure control valve device for controlling the brake fluid pressure of the wheel cylinder of another of said rear wheels, arranged between a second fluid pressure generating chamber of said tandem master cylinder and said wheel cylinder of the other rear wheel; and

(D) a first path which transmits the brake fluid pressure controlled by said first fluid pressure control valve device, to the wheel cylinder of the one of said front wheels connected diagonally to said one rear wheel;

(E) a second path which transmits the brake fluid pressure controlled by said second fluid pressure control valve device, to the wheel cylinder of the other of said front wheels connected diagonally to said other rear wheel;

(F) first and second wheel speed sensors associated with said rear wheels, respectively,

(G) a third wheel speed sensor associated in common with said front wheels, and

(H) a control unit receiving outputs of said first, second and third wheel speed sensors for measuring or judging the skid conditions of said front and rear wheels and for generating instructions for controlling said first and second fluid pressure control valve devices;

wherein said control unit discriminates the frictionally lower one (designated as "low side") of the sides of the road on which said wheels are running, from the measuring or judging results of the skid conditions of said rear and front wheels, or of said rear wheels on the basis of the outputs of said first, second and third wheel speed sensors, or of said first and second wheel speed sensors, said low side being able to change over in accordance with said measuring or judging results at any time, combines logically the measuring or judging results of the skid conditions of said front wheels with the measuring or judging results of the skid condition of the one rear wheel running on the low side for generating the instruction for controlling said first or second fluid pressure control valve device, and generates the instruction for controlling said second or first fluid pressure control valve device, on the basis of the measuring or judging result of the skid condition of the other rear wheel running on the high side (frictionally higher side) independently of those of said front wheels.

10. An anti-skid control apparatus according to claim 9, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one rear wheel which generates said brake maintaining signal sooner than the other rear wheel, is made "low side", before anyone of said front and rear wheels generates said brake relieving signal, or when the front wheels generate said brake maintaining signal sooner than said rear wheels both, the side of the one rear wheel whose slip is more than the other rear wheel'"'"'s slip, is made "low side".

11. An anti-skid control apparatus according to claim 9, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one rear wheel which generates said brake relieving signal sooner than the other rear wheel, is made "low side", or when the front wheels generate said brake relieving signal sooner than said rear wheels both, the side of the one rear wheel whose slip is more than the other rear wheel'"'"'s slip, is made "low side".

12. An anti-skid control apparatus according to claim 9, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one rear wheel which generates said brake maintaining signal sooner than the other rear wheel, is made "low side", before anyone of said front and rear wheels generates said brake relieving signal, or when the front wheels generate said brake maintaining signal sooner than said rear wheel both, the side of the one rear wheel whose speed is lower than the other rear wheel'"'"'s speed, is made "low side".

13. An anti-skid control apparatus according to claim 9, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one rear wheel which generates said brake relieving signal sooner than the other rear wheel, is made "low side", or when the front wheels generate said brake relieving signal sooner than said rear wheels both, the side of the one rear wheel whose speed is lower than the other rear wheel'"'"'s speed, is made "low side".

14. An anti-skid control apparatus according to claim 9, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one rear wheel which generates said brake maintaining signal sooner than the other rear wheel, is made "low side", before anyone of said front and rear wheels generates said brake relieving signal, or when the front wheels generate said brake maintaining signal sooner than said rear wheel both, the side of the one rear wheel whose deceleration is more than the other rear wheel'"'"'s deceleration, is made "low side".

15. An anti-skid control apparatus according to claim 9, in which said measuring or judging results of the skid conditions include a brake increasing signal, a brake maintaining or holding signal and a brake relieving signal, and the side of the one rear wheel which generates said brake relieving signal sooner than the other rear wheel, is made "low side", or when the front wheels generates said brake relieving singal sooner than said rear wheels both, the side of the one rear wheel whose deceleration is made than the other rear wheel'"'"'s deceleration, is made "low side".

16. An anti-skid control apparatus according to claim 9, in which valve apparatus for generating a fluid pressure in accordance with the lower one of the brake fluid pressures of said rear wheels controlled with said first and second fluid pressure control valve devices, is arranged between said first and second paths.