| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic brake device for a vehicle capable of providing a suitable pedal operating feel while preventing over-braking and under-braking. SOLUTION: The pressure of brake fluid in a control chamber R4 is built up by the operation (advance) of a brake pedal 10, and hydraulic pressure within a power chamber R1 adds an assisting force to a brake pedal operating force so as to compress brake fluid in a pressure chamber R3 and output the brake hydraulic pressure. When the hydraulic pressure of brake fluid in a reaction chamber R5 is greater than a predetermined pressure, a reaction disc 39 is elastically deformed by the hydraulic pressure within the reaction chamber R5 to cause sliding movement of a reaction transmitting means 38 and vary the balance of forces acting on a control piston 33 so as to reduce the gradient of pressure buildup of the brake fluid in the control chamber R4 and also to reduce the assisting force produced by the hydraulic pressure within the power chamber R1. When the hydraulic pressure within the reaction chamber R5 is greater than an actuation starting pressure set to be greater than the predetermined pressure, the pressure-receiving area of the reaction transmitting means 38 during its sliding movement is set to be larger than it is when the hydraulic pressure within the pressure chamber R5 is smaller than the actuation starting pressure. |
