Cylinder device

Abstract

Provided is a cylinder device provided with a mechanism for detecting, in three stages, the position of an output member by using the outer periphery of a piston rod of the output member, and the inner wall of a housing. A housing () is provided with an A passage (Ap) for supplying compressed gas, and a B passage (Bp) for discharge to the atmosphere. A piston rod () is provided with a projection () that pulls and pushes down the seal member () together with an annular valve member (). The hollow inner wall inside the housing is provided with a sliding region () having an inner diameter such that a seal member () makes contact therewith to effectively enable the seal function, a loose insertion region () having a large inner diameter such that the sealing function of the seal member () does not work at all and a valve member region () which has a large inner diameter such that the annular valve member () can move up/down, and which stores the annular valve member () while the upper side is surrounded by a ring surface (), the valve member region communicating with the B passage (Bp).