Vehicle brake apparatus

Patent metadata

Field	Value
Publication number	US-9751508-B2
Application number	US-201214416343-A
Country	US
Kind code	B2
Filing date	Aug 31, 2012
Priority date	Aug 31, 2012
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A holding valve ( 61 ) is provided on an individual flow passage ( 51 ) connecting a main flow passage ( 52 ) and a wheel cylinder ( 42 ) to each other. The holding valve ( 61 ) permits communication between an upstream side and a downstream side in an open state to transmit the hydraulic pressure from an accumulator ( 32 ) to the wheel cylinder ( 42 ), and shuts off the communication between the upstream side and the downstream side in a closed state. Moreover, a pressure reducing valve ( 62 ) for realizing communication or shutoff between a reservoir ( 22 ) and a main flow passage ( 52 ) and between the reservoir ( 22 ) and the wheel cylinder ( 42 ) is provided on a pressure reducing individual flow passage ( 56 ) for connecting a reservoir flow passage ( 57 ) and the individual flow passage ( 51 ) to each other. Then, when a driver carries out a return operation on a brake pedal ( 10 ) during antiskid control, a brake ECU ( 100 ) inhibits the holding valve ( 61 ) in the closed state from shifting to the open state, maintains the holding valve ( 61 ) in the open state, and controls the pressure reducing valve ( 62 ) corresponding to this holding valve ( 61 ) to shift to the open state. As a result, a hydraulic pressure in the main flow passage ( 52 ) is decreased via the holding valve ( 61 ) and the pressure reducing valve ( 62 ) in the open state.

First claim

The invention claimed is:

1. A brake device for a vehicle, comprising:
a master cylinder for generating a hydraulic pressure in response to an operation by a driver on a brake pedal;
a power hydraulic pressure source for generating a hydraulic pressure through drive of a pressure pump;
a valve mechanism comprising a plurality of electromagnetic valves to be controlled by electric signals, for carrying out transmission of the hydraulic pressure output from the master cylinder or the power hydraulic pressure source;
a wheel cylinder for applying a braking force to each of wheels through the transmission of the hydraulic pressure output from the master cylinder or the power hydraulic pressure source via the valve mechanism; and
control means for controlling an operation of the valve mechanism,
the valve mechanism comprising:
holding valves, which each comprise an electromagnetic on-off valve, provided for the respective wheels so as to realize at least communication or shutoff between an upstream side to which the hydraulic pressure is transmitted from the power hydraulic pressure source and a downstream side to which the wheel cylinder is connected;
pressure reducing valves, which each comprise an electromagnetic on-off valve, provided in correspondence to the respective holding valves so as to realize at least communication or shutoff between the wheel cylinder and a reservoir; and
a pressure increasing valve, which comprises an electromagnetic valve, for increasing the hydraulic pressure on the upstream side by using the hydraulic pressure from the power hydraulic pressure source,
the control means being configured to, during antiskid control for suppressing an excessive slip in a longitudinal direction of a wheel to which the braking force is applied, when the brake pedal subjected to a depressing operation is operated toward a return direction by the driver:
inhibit, out of the holding valves provided for the respective wheels, the holding valve controlled to be in a closed state based on the antiskid control from shifting to an open state; and
control the pressure reducing valve provided in correspondence to the holding valve in the open state based on the antiskid control to shift to an open state.

2. A brake device for a vehicle according to claim 1 , wherein when the control means controls all the holding valves to be in the closed state based on the antiskid control, the control means cancels the inhibition of the shift to the open state in the holding valve provided for the wheel having the maximum hydraulic pressure in the wheel cylinder, and controls the corresponding holding valve to shift to the open state.

3. A brake device for a vehicle according to claim 2 , wherein the control means estimates the hydraulic pressure in the wheel cylinder for each of a front right wheel, a front left wheel, a rear right wheel, and a rear left wheel of a vehicle, and selects, based on the estimated hydraulic pressure, the holding valve provided for the wheel having the maximum hydraulic pressure in the wheel cylinder.

4. A brake device for a vehicle according to claim 1 , wherein the holding valve in the open state is the holding valve controlled to be in the open state for a predetermined period or more.

5. A brake device for a vehicle according to claim 1 , wherein, during an abnormal state in which there is a possibility of a leak of a working fluid in any of brake systems for transmitting the hydraulic pressure from the power hydraulic pressure source to the wheel cylinders provided on a front right wheel, a front left wheel, a rear right wheel, and a rear left wheel of a vehicle, the control means controls the holding valves to be in the open state so as to maintain the communication between the wheel cylinders provided on rear right and left wheel sides of the vehicle and the power hydraulic pressure source, and controls the holding valves to be in the closed state so as to shut off the communication between the wheel cylinders provided on front right and left wheel sides of the vehicle and the power hydraulic pressure source and to transmit at least the hydraulic pressure from the master cylinder to the wheel cylinders provided on the front right and left wheel sides of the vehicle.

6. A brake device for a vehicle according to claim 1 , further comprising a pressure increasing mechanism connected to the master cylinder and the power hydraulic pressure source, for generating a hydraulic pressure having a predetermined ratio with respect to the master cylinder by using the hydraulic pressure from the power hydraulic pressure source.

7. A brake device for a vehicle according to claim 6 , wherein the pressure increasing mechanism is mechanically operated by the hydraulic pressure output from the master cylinder in response to the operation by the driver on the brake pedal.

Assignees

• Miyazaki Tetsuya
• Toyota Motor Co Ltd

Inventors

• Miyazaki Tetsuya

Classifications

• B60T8/36 Primary

  including a pilot valve responding to an electromagnetic force · CPC title

• B60T8/441

  using hydraulic boosters (B60T8/445, B60T8/446, B60T8/447 take precedence) · CPC title

• B60T13/662

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

• B60T13/142

  Systems with master cylinder · CPC title

• B60T13/686

  in hydraulic systems or parts thereof · CPC title