ELECTRIC PARKING BRAKE CONTROL APPARATUS, ELECTRIC PARKING BRAKE SYSTEM, AND METHOD FOR CONTROLLING ELECTRIC PARKING BRAKE SYSTEM

• US 20080185235A1
• Filed: 01/29/2008
• Published: 08/07/2008
• Est. Priority Date: 02/01/2007
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: SUZUKI, Masakuni
• Granted Patent: US 8,366,211 B2
• Time in Patent Office: Days
• US Class Current: 188/1.11E
• CPC Class Codes: B60T 13/686 in hydraulic systems or parts thereof
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 8/32 responsive to a speed condition, e.g. acceleration or deceleration using electrical circuitry or regulation means B60T8/17 ; B60T8/28 takes precedence; electric devices on electrically propelled vehicles indicating the wheel slip B60L3/10; measuring linear or angular speed per se G01P3/00

Abstract

An electric parking brake control apparatus includes: an electric parking brake actuator that pulls cables connected to respective parking brake units of wheels; a brake actuator that controls braking pressures applied to the wheels by service brakes; a pressure-increase control unit that controls the brake actuator to increase the braking pressures to a predetermined value, when a tension of the cables falls below a predetermined target tension after the cables are pulled until the target tension is achieved; and a tension-increase control unit that controls the electric parking brake actuator to pull the cables until the tension of the cables exceeds the target tension, after the brake pressures are increased by the pressure-increase control unit.

Claims

1. An electric parking brake control apparatus, comprising:

an electric parking brake actuator that pulls cables connected to respective parking brake units of wheels;

a brake actuator that controls braking pressures applied to the wheels by service brakes;

a pressure-increase control unit that controls the brake actuator to increase the braking pressures to a predetermined value, when a tension of the cables falls below a predetermined target tension after the cables are pulled until the target tension is achieved; and

a tension-increase control unit that controls the electric parking brake actuator to pull the cables until the tension of the cables exceeds the target tension, after the braking pressures are increased by the pressure-increase control unit.

2. The electric parking brake control apparatus according to claim 1, wherein the pressure-increase control unit increases at least one of the braking pressures, which is applied to the wheel at which the tension decreases by a large amount, to the predetermined value.

3. The electric parking brake control apparatus according to claim 1, wherein the pressure-increase control unit decreases the braking pressures, after the cables are pulled until the tension of the cables exceeds the target tension.

4. The electric parking brake control apparatus according to claim 1, further comprising:

a malfunction determination unit that determines whether a malfunction has occurred in at least one of the parking brake units when the tension falls below the predetermined target tension after the cables are pulled until the target tension is achieved, and that notifies, if it is determined that a malfunction has occurred in at least one of the parking brake units, a driver of the malfunction.

5. An electric parking brake system, comprising:

an electric parking brake actuator that pulls cables connected to respective parking brake units of wheels;

a brake actuator that controls braking pressures applied to the wheels by service brakes; and

an electric parking control device which includes a pressure-increase control unit that controls the brake actuator to increase the braking pressures to a predetermined value, when a tension of the cables falls below a predetermined target tension after the cables are pulled until the target tension is achieved, and a tension-increase control unit that controls the electric parking brake actuator to pull the cables until the tension of the cables exceeds the target tension, after the braking pressures are increased by the pressure-increase control unit.

6. The electric parking brake system according to claim 5, wherein the pressure-increase control unit increases at least one of the braking pressures, which is applied to the wheel at which the tension decreases by a large amount, to the predetermined value.

7. The electric parking brake system according to claim 5, wherein the pressure-increase control unit decreases the braking pressures, after the cables are pulled until the tension of the cables exceeds the target tension.

8. The electric parking brake system according to claim 5, further comprising:

a malfunction determination unit that determines whether a malfunction has occurred in at least one of the parking brake units when the tension falls below the predetermined target tension after the cables are pulled until the target tension is achieved, and that notifies, if it is determined that a malfunction has occurred in at least one of the parking brake units, a driver of the malfunction.

9. A method for controlling an electric parking brake system including an electric parking brake actuator that pulls cables connected to respective parking brake units of wheels, and a brake actuator that controls braking pressures applied to the wheels by service brakes,

the method comprising:

controlling the brake actuator to increase the braking pressures to a predetermined value, when a tension of the cables falls below a predetermined target tension after the cables are pulled until the target tension is achieved; and

controlling the electric parking brake actuator to pull the cables until the tension of the cables exceeds the target tension, after the braking pressures are increased.

10. The method according to claim 9, wherein at least one of the braking pressures, which is applied to the wheel at which the tension decreases by a large amount, is increased to the predetermined value.

11. The method according to claim 9, wherein the braking pressures are decreased, after the cables are pulled until the tension of the cables exceeds the target tension.

12. The method according to claim 9, further comprising:

determining whether a malfunction has occurred in at least one of the parking brake units when the tension falls below the predetermined target tension after the cables are pulled until the target tension is achieved, and notifying, if it is determined that a malfunction has occurred in at least one of the parking brake units, a driver of the malfunction.