Mechanical displacement detection mechanism suitable for closed oil cavity brake

The invention discloses a mechanical displacement detection mechanism suitable for a closed oil cavity brake, and the mechanism comprises a first-stage installation sleeve and an oil plug assembly which is fixedly disposed outside the first-stage installation sleeve in a sleeving manner, and the interior of the first-stage installation sleeve is movably provided with a push rod in a sealing manner in the axial direction, the front end of the push rod is sequentially and movably connected with a first-stage measuring rod and a second-stage measuring rod, and the front end of the first-stage mounting sleeve is movably provided with a second-stage mounting sleeve which is arranged on the push rod in a threaded and sleeving mode. Three different measurement states are realized by changing the relative positions of the first-stage measurement rod, the second-stage measurement rod and the second-stage installation sleeve, the mechanism can be used as a traditional straight-through type mechanical displacement detec