Determination of the modification amount of involute helical gear

Local stress concentration is very easy to damage the normal operation of helical gear. Adopting the method of helical gear drum trimming to improve the stress or make the stress uniformly distributed can prolong the service life of helical gear and improve the operation efficiency. The core of drum trimming is also the amount of shaping, which directly affects the bearing capacity of helical gears and the gear coupling stress state. How to reasonably select the amount of drum shape modification needs to consider many factors, the most important of which is the linear elastic deformation caused by the gear contact process. That is, the gear itself will produce torsional deformation. In fact, shear deformation does exist, but shear deformation is a secondary factor because its shape variable is very small, so its influence can be ignored. Centrifugal force will not be considered generally, but it will be considered only when the gear is at high speed and large load.

Under the action of centrifugal force, the helical gear teeth may become barrel shaped or drum shaped. During the operation of the helical gear, it is also necessary to consider the changes caused by temperature rise. Humidity generates thermal stress on the helical gear, resulting in the deformation of the helical gear. Similarly, during the actual operation of the helical gear, the distribution of lubricating oil is uneven, and the lubricating oil of the helical gear flows from one end to the other. During the whole process, the helical gear generates heat dissipation, and the humidity distribution of the helical gear changes, The tooth deformation caused by the temperature difference of seed feeding will lead to the contact stress concentration in the contact process of helical gears. Since the tooth deformation caused by the temperature rise of lubricating oil and helical gear is not considered in the analysis, this factor is not considered in the analysis and modification, but it is an aspect of the research in the actual test stage. Only the deformation caused by contact and the influence of centrifugal force during the contact movement are considered, and the drum modification in this regard is mainly considered.

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