PISTON FOR DISC BRAKE FOR FORMING UNIFORM HYDRAULIC PRESSURE IN HOUSING MAIN BORE BY ADDING OIL THROUGH-HOLES

摘要

PURPOSE: A piston for a disc brake is provided to obtain airtightness sealing without reducing the durability of a cylinder body by forming a groove on the outer peripheral surface of a piston and to improve a behavior of the piston by keeping the hydraulic pressure of a main bore in the piston equal by through-holes formed at constant intervals along the circumferential direction of the groove to flow oil. CONSTITUTION: A piston for a disc brake is composed of a disc synchronizing and rotating with a wheel; a caliper bracket having inner and outer pads sliding about both sides of the disc; a caliper body sliding through the caliper bracket to contact the inner and outer pads to the disc; and a cylinder bore formed in the caliper body to receive a piston(132) for reciprocating according to the pressure of oil and pressurizing each pad disposed at the caliper bracket to the disc. The piston comprises a seal groove(132b) combined with a seal and formed on the outer peripheral surface along the circumferential direction; a boot groove(132a) assembled with a boot covering the outside of the piston; and oil through-holes(132c) arranged at the constant interval along the circumferential direction.