MASTER CYLINDER FOR VEHICLE

摘要

According to an embodiment of the present invention, a master cylinder for a vehicle includes: a cylinder housing; a piston which is installed to be able to reciprocate in the cylinder housing; and a sealing member which is installed between the cylinder housing and the piston. A plurality of inclined sides, formed to be inclined with respect to a center axis of the piston and are continuously arranged in a forward movement direction of the piston, are formed on the outside of the piston. On one of the inclined sides which is inclined toward the inside of the piston in the forward movement direction of the piston and supports a sealing member, pressed as internal pressure of the cylinder housing is applied from a front side when the piston moves forward and backward, through-holes are separately formed on different locations of columns in a lengthwise direction of the piston. According to the present invention, a section where an existing horizontal side and an existing inclined side are formed is replaced by one inclined side with a gradient which is relatively gentle compared to an existing inclined side. A first through-hole and a second through-hole are formed on locations of different columns in an axial direction on the inclined side. Accordingly, the master cylinder for a vehicle prevents the sealing member from being deformed suddenly when the piston moves forward and consequently prevents damage of the sealing member. The master cylinder for a vehicle prevents rotation of the sealing member by supporting the sealing member to which internal pressure of the cylinder housing is applied from the front side when the piston moves backward. Therefore, the master cylinder for a vehicle can enhance braking performance by maintaining a function of the sealing member.