Anti-skid control apparatus with brake failure detection means

• US 5,752,751 A
• Filed: 12/26/1995
• Issued: 05/19/1998
• Est. Priority Date: 12/28/1994
• Status: Expired due to Fees

• Current Assignee: Advics Company Limited (Aisin Corp.)
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation), Suzuki Motor Corporation
• Inventors: Suzuki, Shigeki, Tanabe, Yasushi, Nakaura, Tohru, Suzuki, Yoshitaka
• Primary Examiner(s): Poon, Peter M.
• Application Number:
  US08/578,278
• Time in Patent Office: 875 Days
• Field of Search: 303/122, 303/122.02, 303/122.06, 303/122.07, 303/122.09, 303/DIG. 1, 303/DIG. 2, 303/170
• US Class Current: 303/122.06
• CPC Class Codes: B60T 2270/402 Back-up
• CPC Class Codes: B60T 2270/403 Brake circuit failure
• CPC Class Codes: B60T 8/26 characterised by producing differential braking between front and rear wheels using electrical circuitry or regulation means B60T8/17
• CPC Class Codes: B60T 8/347 3 Channel systems B60T8/345 takes precedence
• CPC Class Codes: B60T 8/885 using electrical circuitry
• CPC Class Codes: B60T 8/96 on speed responsive control means
• CPC Class Codes: Y10S 303/02 Brake control by pressure comparison

Abstract

A vehicular anti-skid control apparatus comprises a differential pressure detector for detecting the pressure difference inside brake lines of separate brake channels, a brake failure detector for detecting failure in one of the brake channels based on the anti-skid control state of each brake channel, a brake failure evaluator for evaluating failure of the brake system based on both output signals of the differential pressure detector and brake failure detector wherein the anti-skid control method is changed from normal anti-skid control to a particular anti-skid control when a brake failure occurs.

Claims

1. A vehicular anti-skid control apparatus comprising:

a differential pressure detection means for detecting the pressure difference inside the brake lines of the separate brake channels, and

outputting a differential pressure detection signal when the pressure difference exceeds a predetermined level;

a brake failure detection means for detecting failure in one of the brake channels based on the anti-skid control state of each brake channel, and

outputting a brake failure detection signal when a brake channel failure is detected; and

a brake failure evaluating means for evaluating failure of the brake system when both the differential pressure detection signal and the brake failure detection signal are detected, and

outputting a brake failure evaluation signal;

whereby the anti-skid control method is changed from normal anti-skid control to a particular anti-skid control method while the brake failure evaluating means outputs the brake failure evaluation signal.

2. An anti-skid control apparatus according to claim 1 wherein:

the brake failure detection means outputs the brake failure detection signal when anti-skid control is applied to one of the rear wheels but is not applied to either of the front wheels.

3. The anti-ski control apparatus according to claim 2, wherein said particular anti-skid control method accomplishes anti-skid control by setting the wheel slip threshold value used to evaluate wheel slipping to a higher than normal value.

4. The anti-ski control apparatus according to claim 2, wherein said particular anti-skid control method accomplishes anti-skid control by setting the pressure reducing time of the rear brake fluid pressure to a shorter than normal time.

5. The anti-ski control apparatus according to claim 2, wherein said particular anti-skid control method accomplishes anti-skid control by switching rear wheel braking force control between select-low control and select-high control,

select-low control being a method wherein the right and left wheels are evaluated for a locking tendency, and the brake fluid pressure of the right and left wheels is simultaneously controlled based on the wheels exhibiting a tendency to lock, and

select-high control being a method wherein the right and left wheels are evaluated for a locking tendency, and the brake fluid pressure of the right and left wheels is simultaneously controlled based on the wheels not exhibiting a tendency to lock.

6. An anti-skid control apparatus according to claim 1 wherein:

said particular anti-skid control method accomplishes anti-skid control by setting the wheel slip threshold value used to evaluate wheel slipping to a higher than normal value.

7. An anti-skid control apparatus according to claim 1 wherein:

said particular anti-skid control method accomplishes anti-skid control by setting the pressure reducing time of the rear brake fluid pressure to a shorter than normal time.

8. An anti-skid control apparatus according to claim 1 wherein:

said particular anti-skid control method accomplishes anti-skid control by switching rear wheel braking force control between select-low control and select-high control,

select-low control being a method whereby the right and left wheels are evaluated for a locking tendency, and the brake fluid pressure of the right and left wheels is simultaneously controlled based on the wheels exhibiting a tendency to lock, and

select-high control being a method whereby the right and left wheels are evaluated for a locking tendency, and the brake fluid pressure of the right and left wheels is simultaneously controlled based on the wheels not exhibiting a tendency to lock.