Electric traction shearer is a multi-motor driven shearer with transverse arrangement of motors and normal speed of mining adjusted in the range of 0~12m/min.The traction department not only bears the movement during working and adjustment during non-working of the shearer, but also directly affects the working efficiency and quality of the shearer as well as the production capacity and working performance of the whole shearer.

The traction part is composed of left and right traction reduction gearbox, left and right walking boxes, sliding boots, etc., and is the actuating mechanism for machine walking.Failure of gear reduction box in right traction part of AC traction shearer.The reduction gear motor gear is rated at 110 kW with a maximum traction of 1000 kN.During coal mining, it is found that the left and right traction parts are not synchronized and the right traction efficiency is obviously low. Therefore, after stopping the machine, the gear in the reduction box is moved out of the mine and failure analysis is carried out.

(1) Failure of traction gear is due to breakage of motor gear and wear of idler and shaft gears, and their damage is gradually reduced.

(2) The thickness and hardness of carburized layer of motor gear are not up to the standard, which is the direct cause of failure. The high amount of net carbide and residual austenite in the microstructure results in low fatigue resistance.

(3) It is recommended to temper at high temperature before carburizing, then carburizing and quenching.