Initialization method for electro-mechanical brake

Patent metadata

Field	Value
Publication number	US-9758141-B2
Application number	US-201514701347-A
Country	US
Kind code	B2
Filing date	Apr 30, 2015
Priority date	Jul 9, 2014
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

An initialization method for an EMB may include: opening an in-valve for controlling a flow path through which brake oil is introduced from a master cylinder, closing an out-valve for controlling a flow path through which the brake oil is transferred to an accumulator part, and driving a motor to move a master piston forward; when the master piston is moved by a preset distance after coming in contact with a slave piston which is brought in contact with an inner pad, closing the in-valve and driving the motor to move the master piston backward; when the contact between the master piston and the slave piston is released, determining whether a gap between the master piston and the slave piston is equal to or more than a preset gap; and when the gap is equal to or more than the preset gap, ending initialization of the EMB.

First claim

What is claimed is:

1. An initialization method for an electro mechanical brake (EMB), comprising:
opening an in-valve for controlling a flow path through which brake oil is introduced from a master cylinder, closing an out-valve for controlling a flow path through which the brake oil is transferred to an accumulator part, and driving a motor to move a master piston forward;
when the master piston is moved by a preset distance after coming in contact with a slave piston which is brought in contact with an inner pad for forming a braking force, closing the in-valve and driving the motor to move the master piston backward;
when the contact between the master piston and the slave piston is released, determining whether a gap between the master piston and the slave piston is equal to or more than a preset gap; and
when the gap is equal to or more than the preset gap, ending initialization of the EMB.

2. The initialization method for claim 1 , wherein the determining of whether the gap between the master piston and the slave piston is equal to or more than the preset gap comprises:
when it is determined that the gap is less than the preset gap, opening the out-valve, and driving the motor to move the master piston forward until the master piston comes in contact with the slave piston;
when the master piston comes in contact with the slave piston, opening the in-valve, closing the out-valve, and driving the motor to move the master piston forward by the preset distance; and
when the master piston is moved by the preset distance after coming in contact with the slave piston, closing the in-valve, opening the out-valve, and driving the motor to move the master piston backward.

3. The initialization method for claim 1 , wherein the slave piston is moved by hydraulic pressure which is formed according to the movement of the master piston.

4. The initialization method for claim 1 , wherein as the master piston has a smaller cross-sectional area than the slave piston, the master piston has a larger displacement than the slave piston.

5. The initialization method for claim 1 , wherein as the in-valve is opened, the brake oil is introduced into the slave piston from the master cylinder.

6. The initialization method for claim 1 , wherein as the out-valve is opened, the brake oil introduced into the slave piston is transferred to the accumulator part.

7. The initialization method for claim 1 , wherein when a current of the motor is equal to or more than a preset current while the master piston is moved forward, it is determined that the master piston is brought in contact with the slave piston.

8. The initialization method for claim 1 , wherein the determining of whether the gap between the master piston and the slave piston is equal to or more than the preset gap comprises determining whether the gap between the master piston and the slave piston is equal to or more than the preset gap, by referring to the backward moving distance of the master piston and the displacement of the slave piston which is moved through hydraulic pressure formed by the brake oil introduced into the slave piston.

9. The initialization method for claim 1 , wherein the EMB comprises a hydraulic EMB (hEMB) which brakes a vehicle using the master piston which is moved by the motor and the slave piston which is moved through hydraulic pressure formed by the brake oil introduced into the slave piston according to the movement of the master piston.

10. An initialization method for an EMB, comprising:
a contact determination step of determining whether a master piston and a slave piston are brought in contact with each other before a brake pad and a brake disk are brought in contact with each other by the slave piston moved in connection with the master piston, when an in-valve for controlling entry and exit of brake oil to and from a master cylinder is closed, an out-valve for controlling entry and exit of brake oil to and from an accumulator part is closed, and a motor is rotated to move the master piston forward;
a piston gap determination step of determining whether a moving distance required until the master piston comes in contact with the slave piston corresponds to a first section, when the master piston is moved forward in state where the out-valve is opened, in case where it is determined that the brake pad and the brake disk were brought in contact with each other before the master piston and the slave piston were brought in contact with each other; and
a pad gap securing step of moving the master piston backward until a pad gap between the slave piston and the brake pad corresponds to a second section, when the moving distance of the master piston corresponds to the first section, and ending initialization of the EMB.

11. The initialization method for claim 10 , wherein the piston gap determination step comprises:
an additional forward movement step of moving the master piston forward until the brake pad and the brake disk are brought in contact with each other in a state where the in-valve is opened, when it is determined that the brake pad and the brake disk were brought in contact with each other after the master piston and the slave piston were brought in contact with each other; and
an oil injection step of moving the master cylinder backward by a distance corresponding to the first section by injecting brake oil through the in-valve, when the brake pad and the brake disk are brought in contact with each other through the additional forward movement step.

12. The initialization method for claim 10 , wherein the slave piston is moved by hydraulic pressure which is formed according to the movement of the master piston.

13. The initialization method for claim 10 , wherein as the master piston has a smaller cross-sectional area than the slave piston, the master piston has a larger displacement than the slave piston.

14. The initialization method for claim 10 , wherein as the in-valve is opened, the brake oil is introduced into the slave piston from the master cylinder.

15. The initialization method for claim 10 , wherein as the out-valve is opened, the brake oil introduced into the slave piston is transferred to the accumulator part.

16. The initialization method for claim 10 , wherein the contact determination step comprises determining that the brake pad and the brake disk were brought in contact with each other before the master piston came in contact with the slave piston, when a pressure measured through a pressure sensor connected to a hydraulic pressure chamber is equal to or more than a preset pressure while the master piston is moved forward.

17. The initialization method for claim 10 , wherein the piston gap determination step determines that the master piston is brought in contact with the slave piston, when a current of the motor is equal to or more than a preset current while the master piston is moved forward.

18. The initialization method for claim 10 , wherein the EMB comprises an hEMB which brakes a vehicle using the master piston which is moved by the motor and the slave piston which is moved through hydraulic pressure formed by the brake oil introduced into the slave piston according to the movement of the master piston.

Assignees

• Hyundai Mobis Co Ltd

Inventors

• Kim Jong Sung
• Park Soung Jun

Classifications

• B60T13/08 Primary

  Overrun brakes · CPC title

• B60T8/4872

  pump-back systems · CPC title

• B60T7/20

  specially for trailers, e.g. in case of uncoupling of {or overrunning by} trailer (inertia-actuated overrun brakes B60T13/08) · CPC title