What is a Gear Tooth?

Common gear tooth profile: involute tooth profile and arc tooth profile. See GB / T1356-1988 for the basic profile of the involute tooth profile. Characteristics of involute tooth profile meshing transmission: 1. The transmission ratio is constant; 2. The change in center distance does not affect the transmission ratio; 3. The meshing line is a straight line passing through the nodes.

Gear is an important transmission part widely used in machines and instruments. There are many types of gears with different tooth shapes. The most widely used is involute gears. Gear tooth processing is often divided into chipless processing (such as cold extrusion,

Tooth milling is generally indexed by an indexing head on an ordinary milling machine, and a method of directly cutting the tooth profile of the gear by using a disk milling cutter and a finger milling cutter having the same shape as the gear cogging belongs to the forming method. Finger milling cutters for gears with a processing module greater than 8 and disc milling cutters for gears with a processing module less than 8. During milling, the milling cutter is mounted on the spindle of the milling machine spindle for rotary motion. The indexing head (or chuck) and tailstock center of the workpiece are clamped together and fixed on the working table of the milling machine. The table drives the workpiece and the indexing head to move linearly. After milling a cogging, use the indexing head to rotate the workpiece through one tooth and re-mill another cogging, so that all the cogging is milled in turn, as shown in the figure below.

The following figure is the principle diagram of gear shaping. It is processed by the meshing principle of a pair of cylindrical gears whose axes are parallel to each other.

Correction technology of gear tooth distortion

1. Gear tooth correction method

Through the hardness standard couple (piece of gear), the gear teeth that have been distorted after heat treatment can be corrected to improve its accuracy. Of course, the hardness of the tooth to be corrected cannot be too high, which is suitable for gears such as quenching and tempering, and the correction methods of the tooth of the helical gear and the tooth of the spur gear shaft are shown in a and b in the figure.

Gear tooth correction method

2. Cutting correction method for hard tooth surface

In order to correct the distortion of the gear after quenching and improve the gear meshing accuracy, the grinding tooth surface or grinding tooth surface correction methods are currently used. However, the grinding teeth have little effect on correcting the tooth shape, especially in the case of large gear distortion, but it is beneficial to improve the surface quality of the tooth surface; while the grinding section can not solve the large-scale production of gears because of the low tooth grinding efficiency Distortion problem. In this regard, in some cases, a hard tooth surface cutting method can be used. ^[2]