Case test of non Hertz contact gear design theory

The results show that the EHL center stress design results are very close to those based on Hertz theory, which further shows that EHL center stress can be used as the theoretical basis for gear contact fatigue strength design like Hertz stress. However, the calculation results of EHL center stress are different from the actual gear size, and the relative errors are more than 10%; The design result of non Hertz contact gear is very close to the actual size of the gear, which is in accordance with the requirements of anti scuffing ability.

We have noticed that most of the gears in the above examples are high-speed and heavy-duty gears for locomotives, ships, etc. generally, such gears are required to have high strength, life and reliability. The design of such gears must contain many experience and experimental factors. Therefore, the actual size is based on Hertz It is not surprising that the results obtained by traditional gear design methods are different, but the non Hertz contact gear design method proposed in this paper can surpass the influence of these unknown factors and conform to it quite well.

It must be pointed out that in practical engineering application, more examples reflect that ISO standard is conservative. The actual gear size listed is larger than that designed by ISO standard, and the design result of this method is also larger than that of ISO standard, but this does not mean that the design of ISO standard is unsafe. It is emphasized that the design method can not only ensure the safety of the design, but also ensure the safety of the design. In the case of high speed and heavy load, it is more important to realize EHL.

It should be further pointed out that for high-speed and heavy-duty gear transmission, in order to reduce the meshing impact and uneven load in the tooth direction, tooth surface modification has become a necessary part of the design. In this paper, the analysis and discussion of non Hertz contact based on EHL theory is only carried out in the range of standard involute tooth surface, and the influence of tooth surface modification is not involved. Modification has a great influence on the load distribution and oil film on the tooth surface. After modification, the load distribution and oil film on the tooth surface will change completely. The accurate contact design and modification design of gear must be carried out simultaneously. Therefore, further non Hertz contact analysis combined with tooth surface modification is very important to improve and improve the design of high-speed and heavy-duty gear transmission, which has important engineering application value and theoretical research value, and is an important research direction.

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