Patent ID: 8578711
Filing Date: 2013-11-12
Classification: B60T

Abstract:
1. A master cylinder comprising: a cylinder body which an operating fluid is introduced from a reservoir; a piston which is slidably fitted in the cylinder body and defines a pressure chamber inside the cylinder body; a supply pathway which is formed in the cylinder body and supplies the operating fluid from the reservoir to the pressure chamber; a bypass pathway which bypasses the supply pathway and allows the reservoir to communicate with the pressure chamber; and a check valve which is installed in the bypass pathway and opens a valve when a pressure inside the pressure chamber is lower than a pressure of the reservoir, wherein the check valve comprised of a cup seal disposed inside the bypass pathway, and configured to permit the flow of the operating fluid from the reservoir to the pressure chamber in such a manner that a lip portion of the cup seal is bent to be away from an inner circumferential surface of the bypass pathway, and to interrupt the flow of the operating fluid in a reverse direction in such a manner that the lip portion comes into contact with the inner circumferential surface.