Protection device for copper plating of gear inner hole

The invention relates to a protection device for a mechanical device, in particular to a protection device for copper plating of an inner hole of a gear, and solves the technical problem that the service life of a gear part is influenced due to high difficulty and complex operation of copper plating protection operation when the gear part is subjected to copper plating protection at a non-carburized part. The gear inner hole copper plating protection device comprises a first sleeve, a second sleeve, an inner anode and an outer cathode, one end of the first sleeve is connected with one end of the second sleeve to form a sealed cavity, and the sealed cavity is used for arranging a gear to be plated with copper; a first anode fixing block is arranged at the other end of the first sleeve, a second anode fixing block is arranged at the other end of the second sleeve, and the first anode fixing block and the second anode fixing block are used for fixing an inner anode; the inner anode is used for conducting copper