Master cylinder unit

Patent metadata

Field	Value
Publication number	US-10668909-B2
Application number	US-201615746436-A
Country	US
Kind code	B2
Filing date	Jul 25, 2016
Priority date	Jul 31, 2015
Publication date	Jun 2, 2020
Grant date	Jun 2, 2020

Abstract

Provided is a master cylinder unit including a simulator pressure chamber which communicates with a pressure chamber of a master cylinder and moves a simulator piston by means of an introduced fluid pressure; a biasing chamber in which a biasing mechanism biasing the simulator piston against a fluid pressure introduced into the simulator pressure chamber is disposed; a first seal member which partitions a simulator supply chamber, the simulator supply chamber, and the simulator pressure chamber communicating with a master supply chamber; and a second seal member which partitions the simulator supply chamber and the biasing chamber and allows a brake fluid to flow from the simulator supply chamber to the biasing chamber when a pressure difference occurs between the simulator supply chamber and the biasing chamber.

First claim

The invention claimed is:

1. A master cylinder unit comprising:
a master cylinder that generates a fluid pressure in a pressure chamber inside a cylinder in accordance with an operation amount of a brake pedal;
a reservoir that stores a brake fluid to be supplied to the pressure chamber; and
a stroke simulator that communicates with the pressure chamber, generates a reaction force corresponding to an operation force of the brake pedal, and applies the reaction force to the brake pedal,
wherein the master cylinder includes a master piston which moves inside the cylinder in response to an operation of the brake pedal, and a master supply chamber which is connected to the reservoir at all times and communicates with the pressure chamber when the brake pedal is not in operation,
wherein the stroke simulator has a simulator piston which moves inside a simulator cylinder, a simulator pressure chamber which communicates with the pressure chamber of the master cylinder on one end side of the simulator piston inside the simulator cylinder and moves the simulator piston by means of an introduced fluid pressure, a biasing chamber in which a biasing mechanism biasing the simulator piston against the introduced fluid pressure is disposed on the other end side of the simulator piston inside the simulator cylinder, a simulator supply chamber which is disposed between the simulator pressure chamber and the biasing chamber on an outer circumferential side of the simulator piston, a first seal member which partitions the simulator supply chamber and the simulator pressure chamber, and a second seal member which partitions the simulator supply chamber and the biasing chamber and allows the brake fluid to flow from the simulator supply chamber to the biasing chamber when a pressure difference occurs between the simulator supply chamber and the biasing chamber,
wherein the master cylinder and the stroke simulator are configured to be disposed in a cylinder main body which is integrally formed of one raw material, and
wherein a communication path through which the master supply chamber and the simulator supply chamber communicate with each other is formed by a hole having a central axis which is inclined with respect to a central axial line of the simulator cylinder and intersecting the simulator cylinder, and an opening portion of the hole outside the cylinder main body is closed.

2. The master cylinder unit according to claim 1 ,
wherein the second seal member is a cup seal which is in slide contact with an outer circumference of the simulator piston and is disposed in an annular groove of the simulator cylinder.

3. The master cylinder unit according to claim 1 ,
wherein the pressure chamber communicates with a power module which controls a braking cylinder provided in a wheel, and
wherein the biasing chamber communicates with a bleeder plug for opening and closing the biasing chamber with respect to outside air and communicates with the power module.

4. The master cylinder unit according to claim 1 ,
wherein a relief port is formed in the simulator piston, the relief port causing the simulator supply chamber and the biasing chamber to communicate with each other when the simulator piston comes into contact with a bottom of the simulator cylinder, the bottom facing the one end side of the simulator piston, and blocking communication between the simulator supply chamber and the biasing chamber when the simulator piston is separated from the bottom of the simulator cylinder.

5. The master cylinder unit according to claim 1 ,
wherein the master piston comprises a primary piston which is disposed on the brake pedal side, and a secondary piston which is disposed on a side opposite to the brake pedal of the primary piston,
wherein a primary pressure chamber is provided between the primary piston and the secondary piston, the primary pressure chamber allowing a fluid pressure to generate therein in accordance with an operation amount of the brake pedal,
wherein the pressure chamber is provided between the secondary piston and a bottom of the cylinder, wherein a primary supply chamber is partially formed by the primary piston, the primary supply chamber being connected to the reservoir at all times and communicating with the primary pressure chamber when the brake pedal is not in operation,
wherein the master supply chamber a primary supply is partially formed by the secondary piston.

6. A master cylinder unit comprising:
a master cylinder that generates a fluid pressure in a secondary pressure chamber inside a cylinder in accordance with an operation amount of a brake pedal;
a reservoir that stores a brake fluid to be supplied to the secondary pressure chamber; and
a stroke simulator that communicates with the secondary pressure chamber, generates a reaction force corresponding to an operation force of the brake pedal, and applies the reaction force to the brake pedal,
wherein the master cylinder includes a master piston which moves inside the cylinder in response to an operation of the brake pedal, and a secondary supply chamber which is connected to the reservoir at all times and communicates with the secondary pressure chamber when the brake pedal is not in operation,
wherein the master piston comprises a primary piston which is disposed on the brake pedal side, and a secondary piston which is disposed on a side opposite to the brake pedal of the primary piston,
wherein a primary pressure chamber is provided between the primary piston and the secondary piston, the primary pressure chamber allowing a fluid pressure to generate therein in accordance with an operation amount of the brake pedal,
wherein the secondary pressure chamber is provided between the secondary piston and a bottom of the cylinder,
wherein a primary supply chamber is partially formed by the primary piston, the primary supply chamber being connected to the reservoir at all times and communicating with the primary pressure chamber when the brake pedal is not in operation,
wherein the secondary supply chamber is partially formed by the secondary piston,
wherein the stroke simulator has a simulator piston which moves inside a simulator cylinder, a simulator pressure chamber which communicates with the secondary pressure chamber on one end side of the simulator piston inside the simulator cylinder and moves the simulator piston by means of an introduced fluid pressure, a biasing chamber in which a biasing mechanism biasing the simulator piston against the introduced fluid pressure is disposed on the other end side of the simulator piston inside the simulator cylinder, a simulator supply chamber which is disposed between the simulator pressure chamber and the biasing chamber on an outer circumferential side of the simulator piston, a first seal member which partitions the simulator supply chamber and the simulator pressure chamber, and a second seal member which partitions the simulator supply chamber and the biasing chamber and allows the brake fluid to flow from the simulator supply chamber to the biasing chamber when a pressure difference occurs between the simulator supply chamber and the biasing chamber,
wherein the master cylinder and the stroke simulator are configured to be disposed in a cylinder main body which is integrally formed of one raw material, and
wherein a communication path through which, the primary supply chamber, and the simulator supply chamber communicate with each other is formed by a hole having a central axis which is inclined with respect to a central axial line of the simulator cylinder and intersecting the simulator cylinder, and an opening portion of the hole outside the cylinder main body is closed.

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Koshimizu Naganori
• Owada Hiroshi
• Oosawa Toshiya
• Maruo Ryohei

Classifications

• B60T17/00

  Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features (air compressors per se F04) · CPC title

• B60T8/17552

  responsive to the tyre sideslip angle or the vehicle body slip angle · CPC title

• B60T11/26

  Reservoirs (integral with master controls B60T11/22) · CPC title

• B60T11/34 Primary

  Pressure reducing or limiting valves {(for arrangements for adjusting wheel-braking force responsive to vehicle weight or load B60T8/1831)} · CPC title

• B60T8/17

  Using electrical or electronic regulation means to control braking {(detecting or indicating faulty operation B60T8/885)} · CPC title