ELECTRIC BRAKE SYSTEM

• US 20160159332A1
• Filed: 12/08/2015
• Published: 06/09/2016
• Est. Priority Date: 12/09/2014
• Status: Active Grant

• Current Assignee: HL Mando Corporation (Halla Holdings Corporation)
• Original Assignee: Mando Corporation (Halla Holdings Corporation)
• Inventors: Yang, I-Jin
• Granted Patent: US 9,643,581 B2
• Time in Patent Office: Days
• CPC Class Codes: B60T 13/142 Systems with master cylinder
• CPC Class Codes: B60T 13/146 Part of the system directly actuated by booster pressure
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 13/686 in hydraulic systems or parts thereof
• CPC Class Codes: B60T 13/746 and mechanical transmission of the braking action
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 8/348 4 Channel systems B60T8/345 takes precedence
• CPC Class Codes: B60T 8/4018 Pump units characterised by their drive mechanisms B60T8/4095 takes precedence
• CPC Class Codes: B60T 8/4081 Systems with stroke simulating devices for driver input B60T8/4077 takes precedence

Abstract

An electric brake system includes a reservoir, a master cylinder including first and second hydraulic ports, a simulation device providing reaction force in response to foot force applied to a brake pedal, a hydraulic-pressure supply device, a hydraulic-pressure control unit, and an electronic control unit (ECU). The hydraulic-pressure supply device converts rotational force of a motor into rectilinear motion upon receiving an electric signal from the pedal displacement sensor, and moves a double-acting piston designed to perform reciprocating motion within a hydraulic cylinder. The double-acting piston moves in both directions such that the first hydraulic chamber located at one side or the second hydraulic chamber located at the other side are pressed, resulting in formation of hydraulic pressure.

Claims

1. An electric brake system comprising:

a reservoir configured to store oil;

a master cylinder having first and second hydraulic ports, connected to the reservoir to receive oil from the reservoir;

a simulation device connected not only to a pedal displacement sensor sensing a displacement of a brake pedal, but also to the master cylinder, configured to provide reaction force in response to foot force applied to the brake pedal;

a hydraulic-pressure supply device configured to convert rotational force of a motor into rectilinear motion upon receiving an electric signal from the pedal displacement sensor according to operation of the brake pedal, and move a double-acting piston designed to perform reciprocating motion within a hydraulic cylinder,

wherein the double-acting piston moves in one direction to generate hydraulic pressure by pressing a first hydraulic chamber provided in one end thereof, and moves in another direction to generate hydraulic pressure by pressing a second hydraulic chamber provided in the other end thereof;

a hydraulic-pressure control unit including a first hydraulic circuit connected to the first hydraulic chamber via a first hydraulic passage, and a second hydraulic circuit connected to the second hydraulic chamber via a second hydraulic passage, configured to control flow of hydraulic pressure applied to a caliper brake installed in each wheel via a plurality of valves disposed in the first and second hydraulic circuits;

a first backup passage configured to connect the first hydraulic port to the first hydraulic chamber;

a second backup passage configured to connect the second hydraulic port to the second hydraulic chamber;

a first cut valve disposed in the first backup passage, configured to control flow of hydraulic pressure;

a second cut valve disposed in the second backup passage, configured to control flow of hydraulic pressure; and

an electronic control unit (ECU) configured to control a motor and one or more valves on the basis of hydraulic pressure information and pedal displacement information.

2. The electric brake system according to claim 1, wherein:

the first hydraulic circuit includes a first switching valve disposed in the first hydraulic passage, and a first dump valve disposed in a passage through which the first hydraulic passage is connected to a reservoir; and

the second hydraulic circuit includes a second switching valve disposed in the second hydraulic passage, and a second dump valve disposed in a passage through which the second hydraulic passage is connected to a reservoir.

3. The electric brake system according to claim 2, wherein:

the first and second dump valves are respectively connected to the first and second hydraulic chambers, are selectively opened or closed according to forward or backward movement of the double-acting piston, suction oil from the reservoir, allow the first hydraulic chamber or the second hydraulic chamber to be filled with the suctioned oil, and discharge the oil of the first hydraulic chamber or the second hydraulic chamber to a reservoir.

4. The electric brake system according to claim 2, wherein the first and second switching valves are implemented as normally opened (NO) solenoid valves that remain opened in a normal state and then closed upon receiving a closing signal.

5. The electric brake system according to claim 2, wherein the first and second dump valves are implemented as normally closed (NC) solenoid valves that remain closed in a normal state and then opened upon receiving a closing signal.

6. The electric brake system according to claim 2, wherein:

the hydraulic-pressure control unit further includes a balance valve disposed between the first and second hydraulic circuits such that the two hydraulic circuits are connected to each other or are disconnected from each other; and

one end of a passage in which the balance valve is disposed is connected to downstream of the first switching valve and the first dump valve, and the other end of the passage is connected to downstream of the second dump valve.

7. The electric brake system according to claim 6, wherein the balance valve is implemented as a normally closed (NC) solenoid valve that remains closed in a normal state and then opened upon receiving an opening signal.

8. The electric brake system according to claim 2, wherein the hydraulic control unit further includes:

a normally opened (NO) inlet valve disposed upstream of the caliper brake such that hydraulic pressure transmission to the caliper brake is controlled.

9. The electric brake system according to claim 1, wherein the first and second cut valves are implemented as normally opened (NO) solenoid valves that remain opened in a normal state and then closed upon receiving a closing signal from the electronic control unit (ECU).

10. The electric brake system according to claim 1, wherein:

the first hydraulic chamber and the second hydraulic chamber have different-sized hydraulic regions, and an elastic member is configured to elastically support a double-acting piston in one hydraulic chamber having a relatively smaller-sized hydraulic region.