As an important part of mechanical tools, precision gears have a crucial impact on the accuracy of automation applications. The main factors affecting the accuracy of gear transmission are: the machining accuracy of the gear, the accuracy grade of the gear, the clearance requirements of the gear pair and the contact point requirements of the gear pair.
The radial error of precision gears can generally be reflected by measuring the radial runout of the ring gear. The main reasons for the radial error of gears when cutting teeth are as follows:
1. During adjustment and fixture, the center of rotation of the mandrel and the machine tool table does not coincide.
2. There is a gap between the base hole of the gear blank and the spindle, which is biased to one side when clamping.
3. The positioning of the reference end face is not good, and the inner hole is eccentric to the rotation center of the table after clamping.
The tangential error of precision gears refers to the error that the relative theoretical position of the actual tooth profile moves along the circumference (tangential) when the gear is hobbed. When the tangential displacement occurs, it can be reflected by measuring the tolerance of the change in the length of the common normal.
The main cause of gear tangential error when cutting teeth is the transmission error of the transmission chain. Among the transmission elements of the split-tooth transmission chain, the indexing worm gear under the table has the greatest influence on the transmission error. During the manufacturing and installation process, the indexing worm gear does not coincide with the rotation center of the table (eccentric movement), which causes the rotation angle error of the table, which is reflected on the gear. Secondly, another important factor that affects the transmission error is the manufacturing and installation error of the indexing gear, and a large proportion of these errors are also transmitted to the workbench.
