Brake control systems

• US 5,938,296 A
• Filed: 12/23/1997
• Issued: 08/17/1999
• Est. Priority Date: 12/26/1996
• Status: Expired due to Fees

• Current Assignee: Unisia Jecs Corporation (Hitachi, Ltd.)
• Original Assignee: Unisia Jecs Corporation (Hitachi, Ltd.)
• Inventors: Nakazawa, Chiharu
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US08/996,992
• Time in Patent Office: 602 Days
• Field of Search: 303/113.2, 303/113.1, 303/116.1, 303/119.1, 303/116.2, 303/116.3, 303/116.4, 303/10-12, 303/156, 303/139, 303/144, 180/197, 188/181 A, 188/181 R
• US Class Current: 303/113.2
• CPC Class Codes: B60T 8/4881 having priming means

Abstract

A brake control system includes in a main circuit connecting a master cylinder and a wheel cylinder a normally-open OUT-side gate valve and a fluid-pressure control valve comprising inlet and outlet valves. The system also includes a main pump for discharging brake fluid within a reservoir to the fluid-pressure control valve, and an auxiliary pump for discharging brake fluid to the suction side of the main pump. A normally-closed IN-side gate valve is arranged in an auxiliary suction circuit. A bypass circuit is arranged in parallel with the auxiliary pump, and a circulation solenoid valve is arranged therein. After finishing stabilizing control, a control unit opens the OUT-side gate valve and closes the IN-side gate valve, and opens the circulation solenoid valve during a predetermined period of time.

Claims

1. A system for controlling a brake device for a vehicle with a wheel cylinder for producing braking force, comprising:

a fluid-pressure source, said fluid-pressure source producing a fluid pressure in accordance with driver'"'"'s brake operation;

a main circuit arranged between the wheel cylinder and said fluid-pressure source;

a control valve arranged in said main circuit, said control valve controlling a fluid pressure within the wheel cylinder;

a drain circuit connected to said control valve;

a reservoir arranged in said drain circuit;

a first pump provided with a first suction circuit with a suction valve and a first discharge circuit with a discharge valve, said first suction circuit being connected to said reservoir, said first discharge valve being connected to said control valve;

a second pump provided with a second suction circuit with a suction valve and a second discharge circuit with a discharge valve, said second suction circuit being connected to said fluid-pressure source, said second discharge circuit being connected to said first suction circuit;

a bypass circuit arranged in parallel with said second pump, said bypass circuit connecting said second discharge circuit and said second suction circuit;

a solenoid valve arranged in said bypass circuit;

a motor connected to said first and second pumps, said motor driving said first and second pumps;

a first gate valve arranged between said fluid-pressure source and said suction valve of said second suction circuit, said first gate valve being normally closed;

a second gate valve arranged between said fluid-pressure source and said control valve, said second gate valve being normally open; and

a control unit connected to said control valve, said motor and said first and second gate valves, said control unit carrying out an anti-lock brake control during operation of said fluid-pressure source and a vehicle stabilizing control during non-operation of said fluid-pressure source, said control unit actuating said first and second pumps through said motor and opening said first gate valve and closing said second gate valve during said vehicle stabilizing control, said control unit carrying out a finishing control to open a solenoid valve as normally closed during a predetermined period of time after completion of said vehicle stabilizing control.

2. A system as claimed in claim 1, wherein said solenoid valve is provided with a relief valve for relieving brake fluid to said second suction circuit when with said bypass circuit being closed, a fluid pressure within said second discharge circuit is greater than a predetermined value.

3. A system as claimed in claim 1, wherein said main circuit comprises first and second channel circuits having the same structure,

said control unit controlling said first and second channel circuits such that while said first channel circuit carries out said finishing control, said second channel circuit opens a corresponding first gate valve.

4. A system as claimed in claim 1, wherein said control valve comprises a normally-open inlet valve arranged in said main circuit and a normally-closed outlet valve arranged in said drain circuit,

said control unit opening said outlet valve during said finishing control.

5. A vehicle, comprising:

a wheel cylinder, said wheel cylinder producing braking force;

a fluid-pressure source, said fluid-pressure source producing a fluid pressure in accordance with driver'"'"'s brake operation;

a main circuit arranged between said wheel cylinder and said fluid-pressure source;

a control valve arranged in said main circuit, said control valve controlling a fluid pressure within said wheel cylinder;

a drain circuit connected to said control valve;

a reservoir arranged in said drain circuit;

a first pump provided with a first suction circuit with a suction valve and a first discharge circuit with a discharge valve, said first suction circuit being connected to said reservoir, said first discharge valve being connected to said control valve;

a second pump provided with a second suction circuit with a suction valve and a second discharge circuit with a discharge valve, said second suction circuit being connected to said fluid-pressure source, said second discharge circuit being connected to said first suction circuit;

a bypass circuit arranged in parallel with said second pump, said bypass circuit connecting said second discharge circuit and said second suction circuit;

a solenoid valve arranged in said bypass circuit;

a motor connected to said first and second pumps, said motor driving said first and second pumps;

a first gate valve arranged between said fluid-pressure source and said suction valve of said second suction circuit, said first gate valve being normally closed;

a second gate valve arranged between said fluid-pressure source and said control valve, said second gate valve being normally open; and

a control unit connected to said control valve, said motor and said first and second gate valves, said control unit carrying out an anti-lock brake control during operation of said fluid-pressure source and a vehicle stabilizing control during non-operation of said fluid-pressure source, said control unit actuating said first and second pumps through said motor and opening said first gate valve and closing said second gate valve during said vehicle stabilizing control, said control unit carrying out a finishing control to close said solenoid valve normally and open it during a predetermined period of time after completion of said vehicle stabilizing control.