| 摘要 |
A master cylinder comprises: a cylinder housing; a piston which is movably formed on the cylinder housing so as to form a pressure chamber and a fluid supply chamber; and a sealing member which is interposed between the cylinder housing and the piston. The piston has a recessed portion on the outer peripheral side thereof, wherein the rear-side wall of the recessed portion is formed as an inclined surface, a plurality of first communication ports are formed on the floor surface of the recessed portion, and a second communication port is formed on the rear-side wall of the recessed portion. A communication port, for forming a flow path for generating pressure, and a communication port, for forming a flow path for drag prevention, are formed on the front and the back, respectively, wherein the rear-side wall of the recessed portion formed on the outer peripheral side of the piston is an inclined surface, and the communication port formed on the back for drag prevention is formed on the rear-side wall that is formed as an inclined surface, such that the angle in which the sealing member comes in contact with a part that forms a mouth of the communication port decreases, thereby reducing damage of the sealing member. |
