Determining the profile modification quantity is a complicated problem. If the profile modification quantity is too large, the coincidence degree will be reduced and the excessive profile modification quantity will become error, which is not conducive to reducing vibration. If the profile modification quantity is too small, it will not play its due role. Nowadays, there is no uniform criterion for selecting the profile modification quantity.
In the research of tooth profile modification based on static characteristics, the selection criterion of the maximum modification quantity mostly uses the following two methods: for involute spur gear pairs with coincidence degree less than 2 under fixed design load, when only tooth top modification is carried out, the maximum modification quantity of tooth top is recommended as the comprehensive deformation quantity of the highest point of single tooth engagement under fixed permanent design load; in some modification standards, the maximum amount of tooth isThe modification quantity is recommended as epsilon aM, where epsilon A is the modification quantity coefficient and M is the module of the gear pair.Depending on factors such as gear accuracy, material and modulus, the recommended modification coefficients vary according to different standards, e.g. 0.02 recommended by UK standards and international standards, and 0.005 to 0.02 recommended by Soviet Union standards for cylindrical gears.
All of the above criteria are proposed to achieve smooth transition of load variation or minimum fluctuation of static transmission error during gear transmission.Although the above criteria are difficult to guide the research of tooth profile modification based on dynamic characteristics, they can provide boundary conditions for the optimal design of tooth profile based on dynamic characteristics.