| 摘要 |
A master cylinder device includes a housing whose front side end is closed and which includes a third housing member separating an interior of the housing into a front side chamber and a rear side chamber and having an opening through the third housing member, a first pressurizing piston which includes a main body portion disposed in the front side chamber and which is moved forward by receiving a force for pressurizing the brake fluid to be supplied to a brake devices, and an input piston. In the master cylinder device, an input chamber into which a brake fluid is introduced is defined between a rear end of the main body portion of the first pressurizing piston and the third housing member. The input piston is fitted in the housing with seals, whereby, an inter-piston chamber across which the input piston and the pressure receiving piston face to each other. |
| 主权项 |
1. A master cylinder device for supplying a pressurized brake fluid to a brake device provided in a wheel, comprising:
a housing whose front side end is closed and which includes a partition portion separating an interior of the housing into a front side chamber and a rear side chamber and having an opening through the partition portion; a pressure receiving piston which includes (a) a main body portion having a flange on a rear end thereof and disposed in the front side chamber, and (b) an extension portion extending from the main body portion through the opening of the partition portion into the rear side chamber, the pressure receiving piston being moved forward by receiving a force for pressurizing the brake fluid to be supplied to the brake device; and an input piston which is disposed in the rear side chamber, which is connected to a brake operation member disposed behind the housing, and which can move forward by an operation force applied to the brake operation member, wherein the main body portion of the pressure receiving piston is fitted, at the flange and a portion in front of the flange, in the housing with respective seals therebetween and the extension portion of the pressure receiving piston is fitted in the partition portion of the housing with a seal, whereby: a pressurizing chamber in which the brake fluid to be supplied to the brake device is pressurized by a forward movement of the pressure receiving piston is defined in front of the main body portion of the pressure receiving piston; an input chamber into which a brake fluid from a high pressure source is introduced is defined between a rear end of the main body portion and the partition portion; and an opposing chamber which opposes the input chamber with the flange being interposed between the opposing chamber and the input chamber is defined around the main body portion, wherein the input piston is fitted in the housing with a seal, whereby, between the input piston and the pressure receiving piston, there is defined an inter-piston chamber such that a rear end of the extension portion and the input piston face to each other in a state in which any seal is not present between the input piston and the pressure receiving piston, wherein an inter-chamber communication passage which allows a communication between the opposing chamber and the inter-piston chamber is provided, and a pressurized area of the pressure receiving piston on which a pressure of a brake fluid in the opposing chamber acts and a pressurized area of the pressure receiving piston on which a pressure of a brake fluid in the inter-piston chamber acts are equal, and wherein the master cylinder device further comprises a reaction force applying mechanism which allows a forward movement of the input piston relative to the housing by the operation force, and which applies, to the input piston, a reaction force against the forward movement and with a magnitude according to an amount of the forward movement, as an operation reaction force against an operation of the brake operation member. |
