POWER TRANSMISSION UNIT AND BRAKE SYSTEMS USING SAME

A power transmission unit of a single-acting plunger type includes a ball screw, a ball nut driven by the ball screw, and a plunger piston coupled to the ball nut. A block housing at least partially encloses the plunger piston and the ball screw. A plunger chamber is at least partially defined by the block housing and a face of the plunger piston. The plunger chamber is selectively pressurized by reciprocal motion of the plunger piston with respect to the block housing driven by longitudinal motion of the ball nut. An electric motor selectively drives the ball screw to responsively reciprocate the plunger piston within the plunger chamber. A motor housing at least partially encloses the ball nut, the electric motor, and the plunger piston. The motor housing includes a block lip which is crimped to the block housing to maintain the motor housing in relation to the block housing.