GEAR TOOTH ERROR CAUSED BY HOB MISALIGNMENT

摘要

The hobbing is advantageous in tooth spacing accuracy of the gear being cut or in productivity of it. A good hobbing machine and a hob are necessary to generate good gear teeth. And those have to be used correctly to finish the gear up in high accuracy. But as the machine and the hob generally have not been operated ideally, the gear has troubles of such as the tooth profile error, the pitch error, and the lead error. Especially, the misalignment of the hob decreases the accuracy of the tooth profile of the gear, and the error causes the noise on the gear operation. As the action of the hobbing is as same as it of crossed helical gear, it is necessary to think about the complicated movement in space to estimate the tooth profile errors. We show a relatively simple method to estimate the tooth profile errors caused by misalignment of the hob. In this report, the profile of the gear cut by an involute hob or a standard hob that has straight cutting edge and also the relation between the profile of the gear and radial run-out of the hob are shown. And it is possible to simulate the situation that the tooth profile is waved on one side of tooth flank and it becomes considerably true on the other side in the actual gear