초록 ▼

A brake system includes a pedal feel emulator and a master cylinder with a damping mechanism having a damping piston. When the emulator piston is moved from the at-rest position, fluid is displaced from the emulator through a compensation port and through a flow restrictive orifice in the damping pi

A brake system includes a pedal feel emulator and a master cylinder with a damping mechanism having a damping piston. When the emulator piston is moved from the at-rest position, fluid is displaced from the emulator through a compensation port and through a flow restrictive orifice in the damping piston to the reservoir. Flow rate of the fluid is dependent on the apply rate of the brake pedal. When the brake pedal is applied relatively slowly, sufficient flow volume will occur through the flow restrictive orifice and the damping piston will remain unmoved. As apply rates increase, a sufficient pressure differential will eventually be established across the damping piston to cause it to move. Damping piston movement compensates for rapid fluid displacement out of the variable chamber and enables a desirable pedal feel characteristic where pedal force increases relatively slowly as pedal velocity increases relatively rapidly. As the damping piston movement provides increasing volume, the pressure differential drops across the damping piston and it will cease to move as flow is accommodated solely through the flow restrictive orifice. As this occurs, pedal force will increase more rapidly providing a two-stage damping characteristic.

대표청구항 ▼

[ We claim:] [1.] An emulator damping mechanism comprising:a master cylinder having a body with a stepped master cylinder bore and a transverse bore open to the master cylinder bore;a brake pedal for actuating the master cylinder;a reservoir carried near the body and communicating with the transvers

[ We claim:] [1.] An emulator damping mechanism comprising:a master cylinder having a body with a stepped master cylinder bore and a transverse bore open to the master cylinder bore;a brake pedal for actuating the master cylinder;a reservoir carried near the body and communicating with the transverse bore with a compensation port extending through the body between the transverse bore and the master cylinder bore;a primary piston unit slidably carried in the master cylinder bore;an emulator piston received in an emulator bore wherein the emulator piston is slidable within the emulator bore when the primary piston is substantially unslidable in the master cylinder bore, wherein a variable chamber is defined adjacent the emulator piston and within the emulator bore so that the emulator piston is movable between an at-rest position and a plurality of apply positions while the primary piston unit remains substantially unmoved wherein the variable chamber is contractible creating a fluid displacement wherein the fluid displacement is proportional to an apply rate of the brake pedal; anda damping piston slidably carried in the transverse bore and separating the transverse bore into a damping chamber and a compensation chamber wherein the damping piston has a first bore providing a flow restrictive orifice that is continuously open between the damping chamber and the compensation chamber and wherein when the apply rate is low fluid is displaced from the variable chamber to the reservoir through the flow restrictive orifice without moving the damping piston and when the apply rate is high fluid displaced from the variable chamber is accommodated in the damping chamber as the damping chamber expands by movement of the damping piston.