Patent ID: 6938536

Claim:
Central release device ( 10 ) for a hydraulic clutch actuation system having a cylinder housing ( 12 ), with a cylindrical wall ( 14 ), and a guide sleeve ( 16 ), which is arranged concentrically inside the cylindrical wall ( 14 ) and on which an annular piston ( 18 ), which can be operatively connected to a clutch and can be hydraulically actuated, as required, by way of a pressure chamber ( 20 ) defined by the cylindrical wall ( 14 ) and the guide sleeve ( 16 ), is displaceably guided in order to release the clutch, the guide sleeve ( 16 ) at its end having an annular flange ( 22 ) with an end face ( 24 ) facing away from the annular piston ( 18 ) and a radially outer circumferential surface ( 26 ), by way of which flange the guide sleeve ( 16 ) is fixed to an end face ( 28 ) of the cylinder housing ( 12 ), characterized in that at least one axial groove ( 30 ), which starts at the end face ( 28 ) and in which an insert ( 32 ) is firmly fitted, gripping behind the circumferential surface ( 26 ) of the annular flange ( 22 ), is formed in the cylinder housing ( 12 ) adjacent to the annular flange ( 22 ) in order to fix the guide sleeve ( 16 ) to the cylinder housing ( 12 ), an upper side ( 34 ) of the insert ( 32 ) facing away from the annular piston ( 18 ) lying in a plane defined by the end face ( 24 ) of the annular flange ( 22 ) or in front of this plane, viewed from the annular piston ( 18 ).