Patent ID: 9199620
Filing Date: 2015-12-01
Classification: B60T

Abstract:
1. A vacuum booster comprising: a booster shell; a booster piston that is accommodated in the booster shell to define an interior of the booster shell into a front vacuum chamber and a rear operation chamber, wherein the front vacuum chamber is configured to be communicated with a vacuum source; a valve cylinder connected to the booster piston; an input rod provided in the valve cylinder; a control valve provided in the valve cylinder, the control valve selectively causing the operation chamber to communicate with one of the vacuum chamber and atmosphere in accordance with back and forth movement of the input rod; and an input return spring that is provided between the valve cylinder and the input rod in a compression state and that biases the input rod in a retraction direction, wherein the control valve comprises a first port and a second port are provided in the valve cylinder, the first port establishes a communication between an outer circumferential portion of the vacuum-pressure instruction valve seat and the vacuum chamber, the second port establishes a communication between (i) the operation chamber and (ii) a part between the vacuum-pressure introduction valve seat and the atmosphere introduction valve seat, at least when the input rod is released, a front surface of the flexible portion communicates with the first port, the valve element holder formed of a single member made of a sheet of steel, the single member comprising