Patent ID: 6935112
Filing Date: 2005-08-30
Classification: B60T

Abstract:
1. A master cylinder comprising: a cylinder body in a cylindrical form having one end closed and including a discharge passage and a supply passage for a brake fluid, said supply passage being communicated with a reservoir; a piston slidably disposed in said cylinder body, said piston and said cylinder body forming a pressure chamber therebetween for supplying a fluid pressure to said discharge passage; and a piston seal provided in a circumferential groove formed in said cylinder body, said piston seal having an inner circumferential surface thereof in slidable contact with said piston and being capable of sealingly disconnecting said supply passage and said pressure chamber, wherein: said cylinder body includes a communication groove which opens into said circumferential groove and extends from the circumferential groove toward the closed end of the cylinder body to thereby connect said circumferential groove and said discharge passage; and said communication groove is formed outwardly beyond an outer circumferential surface of the piston seal relative to a radial direction of the cylinder body.