Why can't P/M gears have less than 17 teeth?

Why can't P/M gears have less than 17 teeth?

If you have carefully observed the P/M gears at ordinary times, you will find that they have a certain number of teeth, not random single digits, nor dozens of them, usually not less than 17. Why is there such a regulation? Many friends will be puzzled. Here is a detailed compilation of zhongwei:

Powder metallurgy gear

In order to ensure a very good transmission effect between two gears, generally speaking, the teeth of powder metallurgy gears will not be too few, otherwise problems will occur in the process of connection. Only when their connection is very smooth can the machine run in a stable state. The meshing between gears also requires precise measurement. The angle of inclination between them, their length, and the pressure generated when two gears mesh with each other are all calculated in great detail. If the index is too small, part of the root will be removed, which is called undercutting. However, there is a situation that if the following cutting part is relatively small, the strength and stability of the gear will be greatly reduced.

If we don't talk about the working efficiency of powder metallurgy gear, it can work and operate no matter how many teeth. In addition, 17 is a prime number, that is to say, the number of overlapping times of a gear tooth and other gears is the least under a certain number of cycles, so it will not be at this point for a long time when the force is applied. Gears are precision instruments. Although errors will occur on each gear, the probability of axle wear is too high for 17. Therefore, if it is 17, it will be OK for a short time, but not for a long time.

Therefore, the number of teeth of powder metallurgy gears has very strict regulations and requirements, which will not only require their height and width as well as the spacing between teeth, but also make continuous experimental improvements during manufacturing, and then select excellent solutions after thorough research