Brake apparatus

Patent metadata

Field	Value
Publication number	US-9988028-B2
Application number	US-201515508324-A
Country	US
Kind code	B2
Filing date	Aug 31, 2015
Priority date	Sep 3, 2014
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A brake apparatus activates a stroke simulator OUT valve in a valve-closing direction to increase a pressure in a wheel cylinder with use of brake fluid flowing out of the stroke simulator according to a state of an operation performed by a driver on a brake pedal. Further, when the hydraulic pressure in the wheel cylinder or a first oil passage is brought into a predetermined state, the brake apparatus activates the stroke simulator OUT valve in a valve-opening direction to cause the brake fluid in the stroke simulator to flow out to a low-pressure portion while restricting the brake fluid in the stroke simulator to a predetermined flow amount.

First claim

The invention claimed is:

1. A brake apparatus comprising:
a hydraulic source configured to generate a hydraulic pressure in a first oil passage with use of brake fluid supplied from a reservoir to generate a hydraulic pressure in a wheel cylinder;
a stroke simulator configured to be axially activated in a cylinder by the brake fluid supplied from a master cylinder, the stroke simulator being configured to generate an operation reaction force accompanying a brake operation performed by a driver by activation of a piston dividing at least an inside of the cylinder into two chambers;
a second oil passage provided between one of the two chambers of the stroke simulator and the master cylinder;
a third oil passage provided between the other chamber of the stroke simulator and the first oil passage, the third oil passage being configured to transmit the brake fluid flowing out of the other chamber to the first oil passage;
a stroke simulator IN valve provided in the third oil passage;
a fourth oil passage connecting a portion in the third oil passage between the other chamber and the stroke simulator IN valve, and a low-pressure portion;
a stroke simulator OUT valve provided in the fourth oil passage; and
a pedal feeling generator configured to activate the stroke simulator OUT valve in a valve-closing direction to increase the pressure in the wheel cylinder with use of the brake fluid flowing out of the other chamber into the third oil passage via the stroke simulator IN valve according to a state of an operation performed by the driver on a brake pedal, the pedal feeling generator being further configured to, when the hydraulic pressure in the wheel cylinder or the first oil passage is brought into a predetermined state, activate the stroke simulator IN valve in the valve-closing direction to cause the brake fluid in the other chamber to flow out to the low-pressure portion via the stroke simulator OUT valve while restricting the brake fluid in the other chamber to a predetermined flow amount, thereby generating a pedal feeling of the brake pedal.

2. The brake apparatus according to claim 1 , wherein the pedal feeling generator includes the stroke simulator OUT valve.

3. The brake apparatus according to claim 2 , wherein the stroke simulator OUT valve includes an orifice portion.

4. The brake apparatus according to claim 3 , wherein the orifice portion is provided on one side of the stroke simulator OUT vale that is located closer to the low-pressure portion.

5. The brake apparatus according to claim 2 , wherein the stroke simulator OUT valve is a proportional control valve, and the pedal feeling generator is formed by controlling the proportional control valve to a predetermined valve-opening amount.

6. The brake apparatus according to claim 2 , wherein the stroke simulator OUT valve is a two-position valve, and the pedal feeling generator is formed by repeatedly opening and closing the two-position valve.

7. The brake apparatus according to claim 1 , wherein the pedal feeling generator adjusts an operation speed when the brake pedal is operated.

8. The brake apparatus according to claim 1 , wherein the pedal feeling generator adjusts an operation pressing force when the brake pedal is operated.

9. The brake apparatus according to claim 1 , wherein the pedal feeling generator includes the stroke simulator IN valve, and the stroke simulator IN valve is a one-way valve that permits only a flow of the brake fluid from the other chamber to the first oil passage.

10. A brake apparatus comprising:
a first oil passage connecting a master cylinder configured to be activated according to a brake operation performed by a driver to generate a hydraulic pressure, and a wheel cylinder provided at a wheel;
a pump configured to generate the hydraulic pressure in the first oil passage with use of brake fluid supplied from a reservoir;
a cut valve provided in the first oil passage between the pump and the master cylinder;
a stroke simulator including a piston configured to be axially activated in a cylinder by the brake fluid and dividing at least an inside of the cylinder into two chambers, the stroke simulator being configured to generate an operation reaction force accompanying the brake operation performed by the driver by the activation of the piston;
a second oil passage connecting one of the two chambers of the stroke simulator and a portion in the first oil passage between the cut valve and the master cylinder;
a third oil passage connecting the other chamber of the stroke simulator and a portion in the first oil passage between the cut valve and the wheel cylinder;
a fourth oil passage connecting the third oil passage and a low-pressure portion;
a stroke simulator OUT valve provided in the fourth oil passage; and
a control unit configured to control the pump, the cut valve, and the stroke simulator OUT valve,
wherein the control unit includes
a wheel cylinder pressure increase control unit configured to, according to a state of the brake operation performed by the driver, drive the pump and activate the cut valve and the stroke simulator OUT valve in a valve-closing direction, cause the brake fluid to flow from the master cylinder into the one chamber by an amount according to an amount of the brake operation to activate the piston, and increase a pressure in the wheel cylinder by the brake fluid as much as the amount according to the amount of the brake operation that flows out from the other chamber via the third oil passage due to an increase in a volume of the one chamber, thereby assisting the generation of the hydraulic pressure in the wheel cylinder using the pump, and
a pedal feeling generation unit configured to, when a state of the wheel cylinder, the first oil passage, or the third oil passage shifts to a predetermined state, activate the stroke simulator OUT valve in a valve-opening direction to cause the brake fluid in the other chamber to flow out to the low-pressure portion via the fourth oil passage while restricting the brake fluid in the other chamber to a predetermined flow amount.

11. The brake apparatus according to claim 10 , wherein the pedal feeling generation unit controls a valve-opening state of the stroke simulator OUT valve.

12. The brake apparatus according to claim 10 , further comprising an orifice portion in the fourth oil passage.

13. The brake apparatus according to claim 12 , wherein the orifice portion is provided the low-pressure portion side with respect to the stroke simulator OUT valve.

14. The brake apparatus according to claim 10 , wherein the stroke simulator OUT valve is a proportional control valve, and the pedal feeling generation unit is formed by controlling the proportional control valve to a predetermined valve-opening amount.

15. The brake apparatus according to claim 10 , wherein the stroke simulator OUT valve is a two-position valve, and the pedal feeling generation unit is formed by repeatedly opening and closing the two-position valve.

16. A brake apparatus comprising:
a pump configured to generate a hydraulic pressure in a first oil passage with use of brake fluid supplied from a reservoir to generate a hydraulic pressure in a wheel cylinder, the pump including a first one-way valve that permits a flow of the brake fluid to the first oil passage;
a stroke simulator including a piston configured to be axially activated in a cylinder by the brake fluid supplied from a master cylinder and dividing at least an inside of the cylinder into two chambers, the stroke simulator being configured to generate an operation reaction force accompanying

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Oosawa Toshiya
• Watanabe Asahi

Classifications

• B60T7/042

  by electrical means, e.g. using travel or force sensors · CPC title

• B60T8/409 Primary

  characterised by details of the stroke simulating device · CPC title

• B60T13/66

  Electrical control in fluid-pressure brake systems · CPC title

• B60T13/143

  Master cylinder mechanically coupled with booster · CPC title

• B60T8/4081 Primary

  Systems with stroke simulating devices for driver input (B60T8/4077 takes precedence) · CPC title