VEHICLE BRAKE SYSTEM HAVING PLUNGER POWER SOURCE

The invention relates to an improved plunger assembly for a vehicle brake system. The plunger assembly is operable as a pressure source to control brake fluid pressure supplied to one or more wheel brakes. The plunger assembly comprises a housing defining a cylinder; a reversible motor supported by the housing and having a rotor; and a linear actuator such as a ball screw/nut mechanism driven by the motor. A plunger head is mounted in the cylinder and driven by the linear actuator in first and second opposite directions. Improvements include a linear actuator rotationally supported on the housing by a bearing to actuate the plunger head connection to a ball screw.