The Method of Improving the Machining Accuracy of Gear Grinding
Reasonably choose the form of the grinding allowance and the grinding allowance: If you want to comprehensively improve the precision of the grinding process, you should first choose the corresponding form of the grinding allowance reasonably and scientifically.
In order to completely eliminate the deformation of the tooth shape of the gear and make the gear have a certain grinding accuracy, it is necessary to choose the form of the grinding allowance reasonably. Commonly used grinding allowances include:
A certain amount of grinding allowance is reserved on the tooth surface and the root of the gear. The advantage of this method is that the tooth surface of the gear and the root of the gear are ground at the same time, which not only enables the smooth connection and transition of the tooth surface of the gear and its root, but also greatly improves the bending strength of the gear root. Effectively alleviate the problem of relatively concentrated thermal stress at the root of the gear. With this method of hobbing, the hob does not need to have horns, so there is no need for undercut at the root of the gear. The disadvantages of this method are: on the one hand, there is a relatively large grinding force at the tooth top of the grinding wheel, and the overall production efficiency of this method is relatively low. On the other hand, using this method will cause a large grinding contact surface at the root of the gear, and the cooling is usually not sufficient. Therefore, adverse phenomena such as grinding and cracking often occur, which will seriously affect the fatigue strength of the gear. As well as the bending strength, the service life of the gear is greatly shortened.
There is a uniform residual grinding allowance on the 2 tooth surfaces of the gear. Moreover, when hobbing, the gear root position has a certain amount of digging, and the root of the gear does not leave a grinding allowance. The advantage of this method is: because there is a certain amount of digging at the root of the gear, which makes the outer circle of the grinding wheel have enough space for the knife when grinding, which greatly reduces the threshing of the outer diameter of the grinding wheel quantity. Using this grinding method can greatly improve the service life of the grinding wheel. Studies have shown that this method can increase the life of the grinding wheel by 10%-15% compared with the previous method. In addition to the selection of the form of the grinding allowance, the determination of a reasonable grinding allowance will also have a direct impact on the production efficiency and grinding accuracy of the grinding gear. If the grinding allowance is too large, it is easy to cause a decrease in the hardness of the tooth surface, and it is easy to reduce the bearing capacity and wear resistance of the gear, and the tooth surface is also prone to pitting and other adverse phenomena. If the grinding allowance is too small, it can improve production efficiency to some extent. However, in the actual grinding process, once defects such as uneven grinding allowance or excessive heat treatment deformation occur, black spots are easily left on some tooth surfaces.
Basic conditions for reasonable clamping of the workpiece: the accuracy of gear grinding also depends to a large extent on the clamping accuracy and reliability of the workpiece. In order to ensure the clamping quality of the workpiece, it is first necessary to ensure that the workpiece can be properly clamped when designing the gear. At the same time, designers should attach great importance to the rationality and accuracy of the positioning datum required for gear clamping. In addition, the design of the grinding jig should be as simple and reliable as possible, and the related connecting parts should be minimized to minimize the influence of accumulated errors.
