Hydraulic-pressure control device and hydraulic braking system

Patent metadata

Field	Value
Publication number	US-9663077-B2
Application number	US-201314382945-A
Country	US
Kind code	B2
Filing date	Feb 15, 2013
Priority date	Mar 16, 2012
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A hydraulic-pressure control device includes a regulator including a housing, a control piston in the housing, an input chamber at a rear of the piston, and an output chamber in front of the piston; and an input-hydraulic-pressure control device which controls hydraulic pressure in the input chamber to move the piston forward or backward to raise or reduce hydraulic pressure in the output chamber. The input-hydraulic-pressure control device includes a moving-direction control unit which, when a difference obtained by subtracting an actual hydraulic pressure in the output chamber from a target hydraulic pressure in the output chamber is less than a pressurization-side set value, controls the hydraulic pressure in the input chamber to move the piston backward; and when the difference is greater than a reduction-side set value, controls the hydraulic pressure in the input chamber to move the piston forward.

First claim

The invention claimed is:

1. A hydraulic-pressure control device comprising:
a regulator comprising: a housing; a control piston fluid-tightly and slidably fitted in the housing; an input chamber provided at a rear of the control piston; and an output chamber provided in front of the control piston; and
an input-hydraulic-pressure control device configured to control hydraulic pressure in the input chamber to move the control piston forward to raise hydraulic pressure in the output chamber and configured to control the hydraulic pressure in the input chamber to move the control piston backward to reduce the hydraulic pressure in the output chamber,
wherein the input-hydraulic-pressure control device comprises a moving-direction control unit configured to:
when a difference that is a value obtained by subtracting an actual hydraulic pressure in the output chamber from a target hydraulic pressure in the output chamber is less than a pressurization-side set value, control the hydraulic pressure in the input chamber to move the control piston backward; and
when the difference is greater than a reduction-side set value, control the hydraulic pressure in the input chamber to move the control piston forward, wherein

the input-hydraulic-pressure control device comprises a normal control unit configured to:
raise the hydraulic pressure in the input chamber when the difference is greater than a pressurization threshold value;
reduce the hydraulic pressure in the input chamber when the difference is less than a pressure-reduction threshold value; and
hold the hydraulic pressure in the input chamber when the difference is between the pressurization threshold value and the pressure-reduction threshold value, and

wherein the pressurization-side set value is a value greater than the pressurization threshold value, and the reduction-side set value is a value less than the pressure-reduction threshold value.

2. The hydraulic-pressure control device according to claim 1 , wherein each of at least one of the pressurization-side set value and the reduction-side set value is a value that is determined based on hydraulic pressure corresponding to a sliding resistance caused between the control piston and the housing.

3. The hydraulic-pressure control device according to claim 1 , wherein each of at least one of the pressurization-side set value and the reduction-side set value is a value that is proportional to hydraulic pressure corresponding to twice a sliding resistance caused between the control piston and the housing.

4. The hydraulic-pressure control device according to claim 1 , wherein an absolute value of each of at least one of the pressurization-side set value and the reduction-side set value is determined at a value that is greater in a case where at least one of the hydraulic pressure in the output chamber and the hydraulic pressure in the input chamber is high than in a case where the at least one of the hydraulic pressure in the output chamber and the hydraulic pressure in the input chamber is low.

5. The hydraulic-pressure control device according to claim 1 ,
wherein the regulator further comprises: a high pressure chamber communicable with the output chamber and with a high pressure source; and a high-pressure supply valve provided between the high pressure chamber and the output chamber and configured to establish or interrupt the communication between the output chamber and the high pressure chamber, and
wherein the control piston comprises a valve opening member configured to switch a state of the high-pressure supply valve from a closed state to an open state with the forward movement of the control piston.

6. The hydraulic-pressure control device according to claim 5 ,
wherein the high-pressure supply valve comprises: a seat provided in the housing; a body provided that is movable to and away from the seat; and a spring configured to urge the body toward the seat,
wherein the valve opening member is provided in an orientation in which the valve opening member extends in a direction of the movement of the control piston, and
wherein the control piston further comprises a low-pressure-port communication passage that couples an end portion of the valve opening member which is contactable with the body of the high-pressure supply valve, to a low pressure port formed in the housing so as to communicate with a low pressure source.

7. The hydraulic-pressure control device according to claim 1 , wherein the moving-direction control unit comprises a non-increasing-trend control unit configured to:
control the hydraulic pressure in the input chamber to move the control piston backward when the difference is less than the pressurization-side set value and is not on an increasing trend; and
control the hydraulic pressure in the input chamber to move the control piston forward when the difference is greater than the reduction-side set value, and an absolute value of the difference is not on the increasing trend.

8. The hydraulic-pressure control device according to claim 1 , wherein the moving-direction control unit comprises a change-gradient suppressing unit configured to:
when the difference is less than the pressurization-side set value, control the hydraulic pressure in the input chamber to reduce an increase gradient of the hydraulic pressure in the input chamber with respect to an increase gradient of the hydraulic pressure in the output chamber; and
when the difference is greater than the reduction-side set value, control the hydraulic pressure in the input chamber to reduce a reduction gradient of the hydraulic pressure in the input chamber with respect to a reduction gradient of the hydraulic pressure in the output chamber.

9. The hydraulic-pressure control device according to claim 1 ,
wherein the input-hydraulic-pressure control device comprises: a pressurization control unit configured to raise the hydraulic pressure in the input chamber to raise the hydraulic pressure in the output chamber; and a pressure-reduction control unit configured to reduce the hydraulic pressure in the input chamber to reduce the hydraulic pressure in the output chamber,
wherein the pressurization control unit comprises: a pressurization linear control valve provided between the input chamber and a high pressure source and configured to allow working fluid to flow at a flow rate that is higher in a case where a supply current value for a solenoid of the pressurization linear control valve is large than in a case where the supply current value for the solenoid of the pressurization linear control valve is small; and a first current control unit configured to control a supply current for the pressurization linear control valve and comprising: a pressurization current-value determination unit configured, when the difference is equal to or greater than the pressurization-side set value, to determine the supply current value for the pressurization linear control valve based on the difference and a predetermined pressurization rule; and a pressurization-holding-transition current-value determination unit configured, when the difference is less than the pressurization-side set value, to determine the supply current value for the pressurization linear control valve as a value that is less than the supply current value determined based on the difference and the pressurization rule, and
wherein the pressure-reduction control unit comprises: a pressure-reduction linear control valve provided between the input chamber and a low pressure source and configured to allow the working fluid to flow at a flow rate that is higher in a case where a supply current value for a solenoid of the pressure-reduction linear control valve is small than in a case where the

Assignees

• Kamiya Yusuke
• Uchida Kiyoyuki
• Toyota Motor Co Ltd

Inventors

• Kamiya Yusuke
• Uchida Kiyoyuki

Classifications

• B60T8/326 Primary

  Hydraulic systems · CPC title

• B60T8/4077

  Systems in which the booster is used as an auxiliary pressure source · CPC title

• B60T13/662

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

• B60T8/441

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

• B60T13/142

  Systems with master cylinder · CPC title