Analyze the bearing capacity of the servo reducer gear

Compared with ordinary cylindrical gear reducers and worm gear reducers, involute small tooth difference servo reducers have the advantages of small volume, light weight, large transmission ratio, high efficiency, large load-bearing capacity, reliable operation, and long service life; Compared with cycloidal pinwheel planetary reducers, in addition to the above advantages, in terms of machining, universal cutting tools can be used on universal gear machining machines, thus having the advantages of lower cost. What is the load-bearing capacity? This article analyzes and discusses the load-bearing capacity of a two tooth difference servo reducer gear using the finite element method.

The planetary reducer with small tooth difference is an internal meshing transmission. It is generally believed that a pair of meshing tooth surfaces are convex and concave, with their curvature centers on the same side of the tooth surface and the same concave direction. The difference in curvature radius is small, and the contact deformation results in a larger contact area. Therefore, the contact stress of the gear teeth is greatly reduced, and the contact strength is correspondingly increased. At the same time, bending stress can also be reduced by reducing the tooth top height, thereby improving bending strength. In addition, due to the small tooth difference, there are multiple pairs of small clearance tooth surfaces that are close to meshing around the theoretical meshing point. The small deformation caused by the force on the gear teeth causes these small clearances to disappear, causing these tooth surfaces to come into contact with each other, and thus enter the meshing state. If this judgment is in line with the actual situation, multiple pairs of gear teeth will mesh simultaneously, obviously reducing transmission impact, making operation smoother and noise less. In addition, when the modulus is the same, the transmission capacity should be significantly improved compared to ordinary external meshing cylindrical gear reducers: this judgment has been confirmed by application examples in engineering practice.

The value of involute planetary reducers with small tooth differences lies in the fact that smaller modules transmit larger power. However, determining how much load-bearing capacity can be improved by multi tooth meshing compared to single tooth meshing becomes crucial. As mentioned above, the improvement in load-bearing capacity is mainly due to the engagement of multiple pairs of teeth. How to distribute the force on each pair of teeth is a statically indeterminate problem, and it is impossible to find a Analytical expression. Therefore, traditional algorithms only have to calculate based on a pair of teeth meshing. Although many factors such as tooth shape have been fully considered, it is not possible to consider the changes brought about by multi tooth meshing. Therefore, such calculation results are largely conservative and cannot develop the load-bearing potential of multi tooth meshing. By using the finite element analysis software COSMOSDesign STAR for calculation, this problem can be effectively solved. This article introduces the use of finite element method to compare the load capacity of one pair of teeth meshing and multiple pairs of teeth meshing when the maximum stress is equal, in order to illustrate the difference in load capacity between two tooth difference planetary reducers calculated based on one pair of teeth meshing and multiple pairs of teeth meshing.