Patent ID: 6089676
Filing Date: 2000-07-18
Classification: B60T

Abstract:
A hydraulic brake apparatus for applying braking force to each wheel of a vehicle in response to depression of a manually operated braking member comprising:a cylinder body mountable on said vehicle;a reservoir for storing brake fluid;a master cylinder having a master piston slidably received in said cylinder body to define a pressure chamber ahead of said master piston and a power chamber behind said master piston, the brake fluid in said reservoir being fed into said pressure chamber, and said master piston being moved in response to operation of said manually operated braking member to discharge hydraulic brake pressure from said pressure chamber;an auxiliary pressure source for pressurizing the brake fluid in said reservoir to discharge power pressure of a predetermined value;a control piston slidably disposed in said cylinder body ahead of said master piston to be movable in response to movement of said master piston, said control piston defining ahead thereof a regulator chamber, and exposing a rear end thereof to said pressure chamber, said power chamber being communicated with said regulator chamber to assist forward movement of said master piston;pressure increase valve means for communicating said regulator chamber with said auxiliary pressure source or cutting off the communication therebetween in response to movement of said control piston;pressure decrease valve means for communicating said regulator chamber with said reservoir or cutting off the communication therebetween in response to movement of said control piston; andcounter-force control means for producing counter-force in response to the pressure generated in one of said pressure chamber, said auxiliary pressure source and said power chamber, and applying the counter-force to said pressure increase valve means and said pressure decrease valve means to be moved in a direction opposite to a direction thereof moved by said control piston, said counter-force control means continuously varying the counter-force to be regulated into a predetermined force.