Brake device

Patent metadata

Field	Value
Publication number	US-9428168-B2
Application number	US-201314384201-A
Country	US
Kind code	B2
Filing date	Mar 7, 2013
Priority date	Mar 14, 2012
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

Provided is a brake device that can increase energy efficiency. The present invention is provided with: a master cylinder ( 5 ) that generates fluid pressure alongside the operation of a brake by a driver; and a booster device that reduces the force of operation of the brake by the driver by means of an energy source (fluid pressure unit 86 )). In a predetermined brake operation region, the operation of the booster device is suppressed.

First claim

The invention claimed is:

1. A brake apparatus comprising:
a master cylinder arranged to generate a hydraulic pressure in accordance with a brake operation of a driver;
a brake operation sensing section configured to sense a brake operation amount of the driver;
a reservoir arranged to supply the brake fluid to the master cylinder;
a pump arranged to suck the brake fluid within the master cylinder or the reservoir, and to discharge the brake fluid to a wheel cylinder provided to a wheel; and
a hydraulic pressure control section configured to control a hydraulic pressure of the wheel cylinder by operating the pump and a solenoid valve in accordance with the brake operation amount sensed by the brake operation amount sensing section;
the hydraulic pressure of the wheel cylinder being generated by the hydraulic pressure generated by the master cylinder in a predetermined brake operation region after a start of the brake operation of the driver;
wherein the master cylinder generates the hydraulic pressure by moving a piston in accordance with a displacement of a brake operation member arranged to receive an input of the brake operation of the driver, and the master cylinder includes an operation force varying mechanism arranged to vary a variation rate of a thrust force of the piston to the brake operation force of the driver, or a variation rate of the brake operation force to a displacement amount of the brake operation member, in accordance with the brake operation amount of the driver.

2. The brake apparatus as claimed in claim 1 , wherein the master cylinder generates the wheel cylinder hydraulic pressure when the brake operation amount sensing section senses a start of the brake operation of the driver.

3. The brake apparatus as claimed in claim 1 , wherein the operation force varying member includes a fluid amount varying mechanism arranged to vary a variation rate of a fluid amount supplied from the master cylinder toward the wheel cylinder, to the displacement amount of the brake operation member, in accordance with the brake operation amount of the driver, or a hydraulic pressure varying mechanism arranged to vary a variation rate of the hydraulic pressure supplied from the master cylinder to the wheel cylinder, to the brake operation force of the driver, in accordance with the brake operation amount of the driver.

4. The brake apparatus as claimed in claim 1 , wherein the brake apparatus further comprises a target wheel cylinder hydraulic pressure calculating section configured to calculate a target wheel cylinder hydraulic pressure based on the brake operation amount sensed by the brake operation amount sensing section; and the pump and the hydraulic pressure control section generate the wheel cylinder hydraulic pressure when the calculated target wheel cylinder hydraulic pressure is higher than a predetermined hydraulic pressure.

5. The brake apparatus as claimed in claim 4 , wherein the hydraulic pressure control section includes:
the pump,
a first hydraulic passage connecting a discharge portion of the pump and a discharge port of the master cylinder,
a shutoff valve provided in the first hydraulic passage,
a second hydraulic passage which is bifurcated from a portion of the first hydraulic passage between the discharge portion of the pump and the shutoff valve, and which is connected to the wheel cylinder,
a pressure increasing valve provided in the second hydraulic passage;
a suction hydraulic passage connecting the suction portion of the pump, and the master cylinder or the suction port of the reservoir,
a first pressure decreasing hydraulic passage connecting the second hydraulic passage and the suction hydraulic passage,
a first pressure decreasing valve provided in the first pressure decreasing hydraulic passage,
a second pressure decreasing hydraulic passage which is bifurcated from a portion of the first hydraulic passage between the discharge port of the master cylinder, and the shutoff valve, and which is connected to the suction hydraulic passage,
a second pressure decreasing valve provided in the second pressure decreasing hydraulic passage,
a third pressure decreasing hydraulic passage which is bifurcated from a portion of the first hydraulic passage between the discharge portion of the pump and the shutoff valve, and which is connected to the suction hydraulic passage, and
a third pressure decreasing valve provided in the third pressure decreasing passage.

6. The brake apparatus as claimed in claim 1 , wherein the hydraulic pressure control section includes a suction hydraulic passage directly connecting the suction portion of the pump, and the master cylinder or the suction port of the reservoir.

7. The brake apparatus as claimed in claim 6 , wherein the hydraulic pressure control section includes
the pump,
a shutoff valve provided in a first hydraulic passage connecting the discharge portion of the pump, and the discharge port of the master cylinder,
a second hydraulic passage which is bifurcated from a portion of the first hydraulic passage between the discharge portion of the pump, and the shutoff valve, and which is connected to the wheel cylinder,
a pressure increase valve provided in the second hydraulic passage,
a first pressure decreasing hydraulic passage connecting the second hydraulic passage and the suction hydraulic passage, and
a first pressure decreasing valve provided in the first pressure decreasing hydraulic passage.

8. The brake apparatus as claimed in claim 1 , wherein the hydraulic pressure control section includes a second pressure decreasing hydraulic passage which is bifurcated from a portion of the first hydraulic passage between the discharge port of the master cylinder and the shutoff valve, and which is connected to the suction hydraulic passage, and a second pressure decreasing valve provided in the pressure decreasing hydraulic passage, and the hydraulic pressure generated by the master cylinder and the hydraulic pressure generated by the hydraulic pressure control section are separated by controlling the shutoff valve in a valve closing direction, and by controlling the second pressure decreasing valve in a valve opening direction.

9. The brake apparatus as claimed in claim 7 , wherein the brake apparatus further comprises a third pressure decreasing hydraulic passage which is bifurcated from a portion of the first hydraulic passage between the discharge portion of the pump and the shutoff valve; and a proportional control valve is provided in the third pressure decreasing hydraulic passage.

10. The brake apparatus as claimed in claim 7 , wherein the hydraulic pressure control section is configured to perform a pressure increasing control, to control the shutoff valve in a valve closing direction, to control the pressure increasing valve in a valve opening direction, to control the first pressure decreasing valve in the valve closing direction, and to drive the pump.

11. The brake apparatus as claimed in claim 9 , wherein the hydraulic pressure control section is configured to perform a pressure decreasing control to control the shutoff valve in the valve closing direction, to control the pressure increasing valve in the valve opening direction, to control the third pressure decreasing valve in the valve opening direction, and to stop the pump.

12. A brake apparatus used for a vehicle provided with a regenerative braking device, the brake apparatus comprising:
a master cylinder arranged to generate a brake hydraulic pressure in accordance with an operation of a brake pedal by a driver;
a brake pedal operation amount sensing section configured to sense an operation amount of the brake pedal;
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Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Maruo Ryohei
• Saito Masayuki
• Nakazawa Chiharu

Classifications

• B60T13/662 Primary

  characterised by specified functions of the control system components · CPC title

• B60T8/4081

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

• B60T13/686

  in hydraulic systems or parts thereof · CPC title

• B60T11/224

  with pressure-varying means, e.g. with two stage operation provided by use of different piston diameters including continuous variation from one diameter to another · CPC title

• B60T8/38

  including valve means of the relay or driver controlled type · CPC title