Cylinder device for a disk brake

摘要

It is an object of this invention to provide a cylinder device for a disc brake which facilitates the installation of thick ring portions of a dust boot into an inner circumferential groove in a cylinder bore and which also reduces the weight of a caliper. In this invention a piston is slidably received in the cylinder bore at an actuating portion of the caliper, one thick ring portion is installed into an outer circumferential groove of the piston and another thick portion is installed into an inner circumferential groove adjacent to the open end of the cylinder bore. The dust boot has an intermediate flexible portion received in a stepped large diameter bore stepped up from the cylinder bore. A cutout is formed on a peripheral portion of the stepped large diameter bore surrounding/covering said intermediate flexible portion of the dust boot.