Gear tooth profile error on gears machined by skiving

This study focuses on the theoretical gear tooth profile error of gears machined by conventional skiving. The influences of skiving cutter rake angle on tooth profile errors of gears are analyzed. It is found that the inherent error of skiving cutter and the longitudinal deviation of cutting-edge contributed to the gear profile errors. The influences of skiving cutter resharpening are then analyzed, and it is found that the resharpening amount of skiving cutter has an obvious influence on the tooth profile error of workpiece. Therefore, conventional skiving tools are defective in high accuracy gear machining.

Skiving is an efficient and promising gear cutting technology, which can be used in cylindrical gear machining and is especially excellent in internal gear machining. In recent years, with the developments of CNC technology and tool material, skiving has gradually shown its great potential advantages. The design and manufacture technologies of skiving cutter have made great progress, and various new kinds of skiving cutters have been developed, such as stick blade cutting wheel which is composed of a base wheel and several cutter bars that are assembled on the base wheel and cylindrical skiving tool. Of all the skiving cutters, conventional skiving tool, with a shaper-cutter-shaped structure, is most widely used and studied. However, researches on the tooth profile error of gears machined by the conventional skiving tools are deficient, and some opinions are inaccurate, in which the tooth profile errors are only ascribed to the inherent errors of the skiving tools, and the cutting edges longitudinal deviations of the skiving tools are ignored. Besides, it is also necessary to study the influence of the resharpening of skiving tools, which relates to the tool life and the machining accuracy maintenance of the gears.

Some research is carried in this paper in order to solve the problems of gear tooth profile error. Firstly, the calculating method of tooth profile error of gears machined by conventional skiving is studied and the influences of skiving cutter rake angle on the tooth profile errors of the gears are analyzed. Secondly, the contributing factors of tooth profile error of the gears are investigated. Finally, the influences of skiving cutter resharpening on tooth profile error are analyzed, and the disadvantages of conventional skiving tools, compared with cylindrical skiving tools, are discussed in terms of high accuracy gear machining.

Calculation of gear tooth profile error by skiving

In conventional gear skiving, the relative motion of a skiving cutter and workpiece, at skew axes, is that of rolling of the cutter pitch circle existing in its tooth-end transverse plane (as if it was of zero rakes) on the gear pitch cylinder. The conventional skiving cutter resembles a gear shaper cutter. According to the cutting edge curves of the tool and the relative motion between the workpiece and the tool, the tooth profile coordinates of the workpiece and the tooth profile errors can be calculated.

Further information and calculation detail, you can refer to Guo, Zheng & Mao, Shi-Min & Li, Xiao-E & Ren, Zhong-Yi. (2016). Research on the theoretical tooth profile errors of gears machined by skiving. Mechanism and Machine Theory. 97. 1-11. 10.1016/j.mechmachtheory.2015.11.001.

Through the above analyses on gear tooth profile error, it could be concluded that the resharpening amount of skiving cutter has obvious influence on the tooth profile error of workpiece, and the tooth profile errors of the gears skived by the resharpened skiving cutters are mainly from the inherent errors of the skiving cutters, the cutting edge longitudinal deviations and the extra errors caused by skiving cutter resharpening. If the tooth profile error of workpiece is reduced by cutter tooth profile modification, the skiving cutter flanks should be ground to complicated surfaces with different normal section curves, which is unpractical and difficult to achieve. If the skiving cutter flanks are ground to simple helicoid surfaces with identical normal section curves which are easier to achieve, there must be tooth profile error of the workpiece after the skiving cutter is resharpened, so the machining accuracy of the workpieces cannot be maintained.

Cylindrical skiving tools can avoid the above problems of conventional skiving tool. This is because the cylindrical skiving tool is similar to a cylindrical gear, and when the tool is resharpened, the shape of the cutter edge and the addendum radius of the cutter will not change, so the tool can be resharpened for many times, and the machining accuracy of the workpieces can be maintained. What’s more, the tool design and manufacture methods are simple.

In contrast with conventional skiving tool, if the relief angle of the tool is sufficient during the skiving process, cylindrical skiving tool is more practical in terms of high accuracy gear machining. Different from the conventional skiving tool, the installation of the tool relative to the workpiece needs to be adjusted so as to get the necessary relief angle, and the cutter edges are curves on the rake face enveloped by the tooth flanks of the workpiece.

gear tooth profile error by skiving cutter

Conclusion

Theoretical analysis is carried out to study gear tooth profile error of gears machined by conventional skiving tool. The influences of skiving cutter rake angle on the tooth profile errors of gears are extensively investigated. The contributing factors of the tooth profile errors of the workpieces are studied, and the influences of tool resharpening on the tooth profile errors are further analyzed.

Finally, the disadvantages of conventional skiving tools, compared with cylindrical skiving tools, are discussed. It can be concluded as follows:

  1. There is gear tooth profile error of the gears skived by conventional skiving tools, and the rake angle of the skiving cutter has an obvious influence on the tooth profile error of workpiece.
  2. The gear tooth profile error of the gears skived by conventional skiving tools mainly come from the inherent errors of the skiving cutters and the cutting edge longitudinal deviations, and inherent-error-corrected cutters cannot eliminate the tooth profile errors of the gears completely only by eliminating the inherent errors of the skiving cutters.
  3. The gear tooth profile error of the gears skived by resharpened conventional skiving tools are mainly from the inherent errors of the skiving cutters, the cutting edge longitudinal deviations and the extra errors caused by skiving cutter resharpening. Cylindrical skiving tools are more practical than the conventional skiving tools in terms of high accuracy gear machining.

Reference

Guo, Zheng & Mao, Shi-Min & Li, Xiao-E & Ren, Zhong-Yi. (2016). Research on the theoretical tooth profile errors of gears machined by skiving. Mechanism and Machine Theory. 97. 1-11. 10.1016/j.mechmachtheory.2015.11.001.

Artikel Terkait

Belajar Matematika Lanjut menjadi mudah dengan sof... Belajar matematika lanjut atau yang sering kita kenal dengan istilah Apllied Mathematics merupakan hal yang sangat menakutkan bagi sebagian besar maha...
Cara mengasah endmill dengan menggunakan grinding ... Sobat Mesin...Salah satu hal yang sangat menentukan terhadap kualitas hasil praktik pemesinan frais adalah kemampuan operator dalam mengelola peralata...