Gear couplings are suitable for the connection of heavy-duty high-speed horizontal transmission shafts. Generally, the failure of gear transmission equipment is mainly related to the original design, heat treatment process, installation accuracy, lubrication conditions, etc. The main forms of failure include tooth surface wear, gluing, deformation, indentation, tooth surface fatigue, cracks and tooth breakage. The load-bearing capacity of a gear coupling is related not only to the material and heat treatment, but also to the direction and magnitude of the relative displacement between the two shafts, as well as to the sliding speed and lubrication state between the meshing tooth surfaces.

The gear coupling is characterized by its compact structure, large load-bearing capacity, wide range of operating speeds and reliable operation. By taking samples of the gear pair of the coupling for metallographic and hardness analysis, and based on the remeasurement of the installation dimensions, we verified the gear coupling in combination with the design parameters and actual working conditions. Through the surface analysis of the damaged parts on site, it was concluded that the damage of the carbon brush of the motor led to the inability to effectively release the shaft current, and a breakdown effect occurred between the teeth and the end face clearance of the gear coupling. Pitting occurs on the gap surface and causes the grease in that area to fail.