Parking brake mechanism for rail vehicle

The utility model provides a parking brake mechanism for a rail vehicle. The parking brake mechanism for the rail vehicle comprises a cylinder body, a cylinder cover, a piston, a lead screw and compression springs, wherein a rotatable ratchet barrel is arranged in the cylinder cover, a one-way ratchet is arranged on the top of the ratchet barrel, the lower end of the lead screw is connected with an extension bar, a rotation-preventing sleeve is arranged in the center of the piston, a rotation-preventing bushing is fixedly arranged in the rotation-preventing sleeve, and is used in cooperation with the lead screw through feather keys, the rotation-preventing sleeve is sleeved with a rotatable sleeve nut, the sleeve nut and the rotation-preventing sleeve are locked in the axial direction, the inner side of the sleeve nut and the lead screw are in screw thread fit, and the outer side of the sleeve nut is used in cooperation with the ratchet barrel through feather keys. According to the parking brake mechanism for