The transmission gear of heavy equipment used in the bending fatigue test is designed based on the gear applied in the actual factory. The success of gear design and manufacturing is related to the success or failure of the whole bending fatigue test. A successfully designed gear needs to meet the following conditions:

1) The gear test piece shall be similar to the actual gear as much as possible;

2) The material of gear sample shall be the same as that of simulated gear;

3) The machining process of gear specimen must be exactly the same as that of simulated gear.

During the processing of the test gear, the processing accuracy of the previous process shall be tested before processing, and each piece must be inspected to eliminate the waste products. All cold and hot processing of gears shall be carried out according to the design process, and corresponding records and inspections shall be made. If the data records are incomplete, it is not allowed to enter the next process. The heat treatment conditions are quenching and tempering plus surface quenching, the effective hardened layer thickness is 0.9-1.1mm, and the surface hardness is HRC58-62. The processing and heat treatment shall be carried out and inspected according to the requirements of me level (when the gear material quality and heat treatment quality are high, the fatigue strength limit shall be reached). During tooth grinding, excessive arc of tooth root shall not be damaged and grinding tempering shall not occur. All gears shall strictly ensure the consistency of materials and processing. There shall be no flash and burr, the ruler side chamfering is 0.5×45 degrees, and the tooth top side circle r = 0.5.

The gear sample designed and processed according to the above requirements is shown in the figure: