A Spherical Involute Straight Bevel Gear Pair and Its Tooth Profile Modification Method

Abstract

A spherical involute spur bevel gear pair and a method for reshaping a gear profile thereof. The spherical involute spur bevel gear pair comprises a driving gear (1) and a driven gear (2) engaging with each other. A gear profile of the gears is divided into two sections. A section AB is a theoretical spherical involute. A section BD' is a spherical reshaping curve. B is a starting point for reshaping. The reshaping method for a gear profile of a gear pair comprises the following steps: software modeling → manufacturing a reshaping mold → batch manufacturing, wherein gear profile reshaping of both the driving gear and the driven gear of the spherical involute spur bevel gear pair uses a tooth top edge shaping method; a reshaping curve is a curve of a spherical surface on which the spherical involute is located; a reshaping direction is a normal direction of the spherical involute; and a starting point for reshaping and a reshaping amount can be acquired by means of optimization according to a finite element algorithm. In the invention, the impact caused by engaging and disengaging of gears is reduced and vibrations and noise are also reduced, thereby improving engagement quality and service life of a gear pair.

Description

technical field [0001] The invention relates to the technical field of gear design and manufacture, in particular to a spherical involute straight bevel gear pair and a tooth profile modification method thereof. Background technique [0002] The transmission ratio change during gear meshing is considered to be one of the sources of gear vibration and noise. In order to ensure a constant transmission ratio, the tooth profile curve of the spur bevel gear pair should be a spherical involute; however, due to the transmission characteristics of the spherical involute I don’t know much about it. Straight bevel gears are generally modeled with back cone involutes. Although the back cone involute is very close to the spherical involute and the modeling is convenient, there are always errors in this modeling method. When the spherical radius The smaller the ratio to the gear modulus, the greater the error; the smaller the ratio of the spherical radius to the gear modulus of the strai...

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Problems solved by technology

[0002] The transmission ratio change during gear meshing is considered to be one of the sources of gear vibration and noise. In order to ensure a constant transmission ratio, the tooth profile curve of the spur bevel gear pair should be a spherical involute; however, due to the transmission characteristics of the spherical involute I don’t know much about it. Straight bevel gears are generally modeled with back cone involutes. Although the back cone involute is very close to the spherical involute and the modeling is convenient, there are always errors in this modeling method. When the spherical radius The smaller the ratio to the gear modulus, the greater the error; the smaller the ratio of the spherical radius to the gear modulus of the straight bevel gear in a car differential, the greater the tooth profile error, and the resulting change in transmission ratio The vibration and noise caused will be obvious; at present, although the batch forging of spherical involute bevel gears for differentials has not yet been realized, the transmission of spherical involute bevel gears is better than that of plane involute bevel gears. The advantages of it make it a hot spot in the research and development of universities and enterprises;

[0003] Due to the existence of loaded elastic deformation, when the gear pair engages in and out, the base joints of the planet and the half shaft are not equal, that is, the interference between the gear pair and the engagement occurs, which brings the vibration and noise of the gear pair. There have been some studies on tooth profile modification of open-line straight bevel gears. The common point of these studies is that the theoretical spherical involute is drawn in the 3D software, and the modified part is replaced by a straight line, parabola and other planar curves. The advantage is that the image is intuitive. It is easy to design, but the disadvantage is that the amount of modification and the direction of modification cannot accurately reflect the deformation direction and size of elastic deformation, and there may be problems of excessive or insufficient modification

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