ANTI-LOCK HYDRAULIC BRAKE SYSTEM

摘要

An anti-lock hydraulic brake system is described having a bypass line to a pump used to evacuate and pressurize the wheel brakes during antilock control. A pressure control valve in the bypass line regulates the pressure in the pressure line to the master cylinder pressure level. A low pressure accumulator absorbs recirculated fluid flow from the bypass line. A pressure operated valve opens only when a difference in pressure between the master cylinder pressure and the pump outlet pressure line pressure develops. The consequence is that a non-return valve a and pressure operated valve in combination bring about isolation of the master cylinder during antilock control to prevent brake pedal reaction to pump pressure developed during a braking pressure control operation. When the accumulator is fully charged, the bypass line is closed by means of a shut-off valve operated by an accumulator piston so that the pump delivers fluid via the pressure valve (18) back into the master cylinder (1).