a. In, two kinds of test gears adopt the same material, the same machining and heat treatment process, only the difference between shot peening and non shot peening. The shot peening gears are processed in the same batch to ensure the consistency of shot peening strengthening effect on the gear surface.
b. The bending fatigue test was carried out on the same high frequency testing machine for the test gear with shot peening and without shot peening. The test fixture was loaded on the top of single tooth to ensure the consistency of loading position in each test.
c. In order to solve the problem of stability and reliability of test data, the test data obtained by group method is screened and processed by suspicious data, and the test data under low stress is about 12, which ensures the reliability of test data.
d. The tooth root stress calculation adopts the calculation method in GB / T 14230. Because the geometric parameters of the shot peened gear and the non shot peened gear are the same, the parameters selected in the calculation are the same, and the stress calculation results can reflect the difference of the tooth root stress between them.
e. Compared with the S-N curves of two kinds of gears, the power function index of P50 curve of shot peened gear is -0.075, the power function index of p99 curve is -0.083, the power function index of P50 curve of non shot peened gear is -0.077, and the power function index of p99 curve is -0.083. It can be seen that the power function index of S-N under the same survival rate of two kinds of gears is almost the same. It is shown that the power function index of the S-N curve of the same module and tooth width is similar.