Movable arm oil cylinder pin shaft fixing mechanism for excavator

The utility model discloses a movable arm oil cylinder pin shaft fixing mechanism for an excavator. The movable arm oil cylinder pin shaft fixing mechanism comprises a movable arm oil cylinder pin shaft limiting ring (1), a check block (2) and a movable arm oil cylinder pin shaft installing lug plate (3). The movable arm oil cylinder pin shaft limiting ring is fixedly connected with one end of a movable arm oil cylinder pin shaft (4) and provided with a notch (11), one side of the check block is provided with a step groove structure (21), the longitudinal section of the step groove structure is of an L-shaped structure, the check block is further provided with a mounting hole (22) penetrating the check block in the height direction, a thread mounting hole (31) is formed nearby a movable arm oil cylinder pin shaft mounting hole in the movable arm oil cylinder pin shaft installing lug plate, and the sum of the distance between the notch and the center of the movable arm oil cylinder pin shaft and the distance between the groove bottom plane of the step groove structure and the center of the mounting hole is matched with the distance between the center of the thread mounting hole and the center of the movable arm oil cylinder pin shaft mounting hole. According to the pin shaft fixing mechanism, the limitation of the axial-direction and radial-direction freedom degrees of the movable arm oil cylinder pin shaft can be achieved by only through one mounting bolt.