Expansion fixing gear device for aviation gas turbine starter

The utility model discloses a gear expanding and fixing device for an aviation gas turbine starter, which comprises a fixing base used for being installed on the end face of a gear cavity provided with a gear, and an expanding sleeve coaxial with a rotating shaft where the gear is located is arranged on the fixing base. The bottom end of the expansion sleeve is provided with at least two clamping pieces used for clamping the outer wall of the rotating shaft where the gear is located, and the clamping pieces are made of elastic materials. The clamping pieces are made of rubber or plastic or spring pieces. A push rod coaxial with the expansion sleeve is arranged in the expansion sleeve in a sleeved mode, and the bottom end of the push rod is in a plane shape. According to the utility model, the gear can be expanded and fixed, and the gear is prevented from shaking left and right, so that the meshing clearance between the gears is fixed, the meshing clearance between the gears is conveniently measured, and the r