The test gear test gear has the modulus m=4, the helix angle=10, and the tooth width b=8mm. The gear manufacturing process route is: blank-forging-normalizing treatment-roughing blank-inspection, testing-tempering treatment-semi-finishing Car - hobbing - carburizing - car carbon layer - finishing car - quenching - scraping. The average hardness of the tooth surface is greater than 59HRC, and the surface roughness of the tooth surface is Ra=0.8m1.6m. The chemical composition and mechanical properties of the material are in compliance with the general inspection requirements of GB/T8539.
The test machine and the test fixture test machine are HS-LETRY100kN microcomputer-controlled high-frequency fatigue test machine. The machine has high loading precision and the test data can be accurately displayed and recorded. The test machine loading frequency is f=126131, stress ratio R=0.2. Clamp As shown, the clamp has an automatic loading function that distributes the load evenly along the tooth direction.
The failure criterion shows visible cracks, load or frequency drop 510, and broken teeth along the root. The test protocol and the data test protocol use a single-tooth pulsation loading method. The tested gears were randomly drawn from all of the test gears and avoided that the tested teeth of the same stress level were from the same gear.
1) In the medium life zone, the stress level of 23 is selected, and the median fatigue life and safe life are determined by the group method; 2) Under the specified cycle number N0=3106, the conditional fatigue limit is determined by the lifting method. Basic assumptions for statistical analysis and processing of data 1) In the group test, the fatigue life follows a lognormal distribution; in the lift method test, the fatigue strength follows a lognormal distribution; 2) in the medium life region, the PSN curve Following equation (1), it is straight in logarithmic coordinates, that is, conforms to equation (2).
Test data analysis results Before the lifting method test, the rough fatigue limit value is estimated by the group method, and then the stress level difference is determined according to the estimated value. (Indicating that in this test, all stress parameters s are replaced by load F, the unit of F is kN) Lifting test data load Fj/kN test cycle number 21.001.2506E 061.1755E 062.4180E 0520.501.7326E 06>3.0E 068.0490E 05>3.0E 0620.00>3.0E 065.1060E 05>3.0E 0619.50>3.0E 06 Lifting method obtained by lifting method test data processing result median fatigue strength F5020.4167 subsample standard deviation / kN0.372790 - fatigue strength F90 /kN20.416795-Fatigue strength F95/kN19.938999-Fatigue strength F99/kN19.803699.9-Fatigue strength F99.9/kN19.5498 According to the above data analysis results, it can be clearly seen that the reliability is 90, 95, 99 respectively The fatigue strength at 99.9 is replaced by the ultimate load in this test for the convenience of recording.
Carrying capacity calculation The theoretical value of the bending fatigue limit of the ZY-1 double circular arc gear obtained by finite element analysis is used for the calculation of the bearing capacity of the universal reducer series. Taking the single-stage reducer as an example, the calculation results are as shown. The load capacity of the series of hardened involute gear reducers with the same specifications.
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