Patent ID: 8840199

Claim:
A slave cylinder comprising: a piston cylinder housing a first piston to be moved forward by a motor and; a second piston disposed in front of the first piston, wherein the piston cylinder has a first slave hydraulic chamber formed between the first piston and the second piston, wherein the piston cylinder defines a first input port communicating with the first slave hydraulic chamber, wherein the first input port is connected to a master cylinder and is to be cut off from the master cylinder by a first shut-off valve, wherein the piston cylinder has a second slave hydraulic chamber formed between the second piston and an end of the piston cylinder, wherein the piston cylinder defines a second input port communicating with the second slave hydraulic chamber, wherein the second input port is connected to the master cylinder and is to be cut off from the master cylinder by a second shut-off valve, wherein the piston cylinder defines: a first atmosphere port communicating with a first back chamber which is disposed in rear of the first slave hydraulic chamber and which moves together with the first piston; and a second atmosphere port communicating with a second back chamber which is disposed in front of the first slave hydraulic chamber and in rear of the second slave hydraulic chamber and which moves together with the second piston, wherein the slave cylinder further comprises a restricting structure to restrict the second piston from moving backward, wherein the restricting structure comprises a hole formed in the second piston, and a stopper fixed to the first piston, wherein the stopper is disposed in the hole of the second piston and engaged with the second piston, and wherein the second atmosphere port is disposed in the vicinity of the restricting structure in an axial direction of the piston cylinder.