Gear is a kind of spare parts that are widely used in life, whether it is aviation, freighter, automobile and so on. However, when the gear is designed and processed, its number of gears is required. If it is less than seventeen, it cannot rotate. Do you know why?
First of all, the reason why the gears can rotate is because a pair of good transmission relationship should be formed between the upper gear and the lower gear. Only when the connection between the two is in place, can its operation be a stable relationship. Taking involute gears as an example, two gears can only play their role if they mesh well. Specifically, they are divided into two types: spur gears and helical gears.
The coefficient of the height of the addendum of the standard spur gear is 1, the coefficient of the height of the dedendum is 1.25, and the degree of its pressure angle must reach 20 degrees. It's the same two gears.
If the number of teeth of the embryo is less than a certain value, a part of the root of the tooth root will be dug out, which is called undercutting. If the undercut is small, it will affect the strength and stability of the gear. The seventeen mentioned here are for gears.
In addition, seventeen is a prime number, that is to say, the number of overlaps between a certain tooth of the gear and other gears is the least under a certain number of turns, and it will not stay at this point for a long time when the force is applied. Gears are precision instruments. Although there will be errors on each gear, the probability of wheel shaft wear at Seventeen is too high, so if it is Seventeen, it will be fine for a short period of time, but it will not work for a long time.
Post time: Mar-15-2023