Suction pressure operated booster for automobile brake systems

摘要

A negative pressure booster for an automobile brake system includes a housing having an inside cavity, a power piston being provided in the housing for dividing the inside cavity of the housing into a suction pressure chamber and an atmospheric pressure chamber. An output rod is associated with the power piston and extends outwardly through the housing. A manually actuated control valve is carried by the power piston for controlling the communication between the suction pressure and atmospheric pressure chambers and the communication between the atmospheric pressure chamber and atmosphere. A pipe is provided for connecting the suction pressure chamber with a source of negative pressure. The power piston includes a hub made of a plastic material formed with a stepped axial hole having a large diameter hole section and a small diameter hole section which are connected together through a stepped shoulder portion, the output rod having a head axially slidably received in the large diameter portion and a radially extending annular flange adapted for abutting engagement with an end surface of the hub.