As a transmission mechanical component, gears have gradually become closely related to life. For example, driving cars need to use gears, and electric vehicles and bicycles also need gears. In addition, gears mainly refer to gears continuously meshing on the rim to transmit power, which first appeared at the end of the 19th century. At that time, Switzerland developed the variable drawing method and also processed gears. Subsequently, the United Kingdom, the United States, and Germany also developed gears. And with the development of science and technology, the materials and processing methods of gears have also been upgraded and transformed, and finally established as arc gears.
It is reported that China, through decades of hard work and development, once reached 68.3 billion yuan in gear production value in 2005, and it is also the industry with the fastest growth rate in the output value of my country's machinery industry. The most important thing is that in addition to a certain mold, the development of gears also requires an extremely advanced machine tool as a support, and also has extremely stringent requirements for the number of teeth.
According to our understanding, most gears have around 17 teeth, of course, at least 14 teeth. However, in real life, there are not many types of gears with gears less than 17. The reason why the number of gears is set at 17 is entirely due to safety considerations in the manufacturing process. If the number of gears is too small, the root thickness may become thinner when the machine is cutting. <span data-bjh-target=" is also called undercutting. After continuous testing, it is found that if the number of teeth is controlled at around 17, Then it can greatly avoid the phenomenon that the root is damaged by the rack knife. Of course, this also needs to be calculated in detail before the specific cutting method can be known. It can be said that avoiding undercutting is the greatest protection for the gear.
However, usually gears are mainly straight teeth, and helical teeth rarely appear, but why are automobile gears arranged in helical teeth? In fact, the gearbox of a car is composed of multiple gears. During driving, it is necessary to bring power through the meshing of the gears. The use of helical teeth can make the gears mesh better. Moreover, under full load, the helical teeth can be made step by step like a screw, which not only has a higher degree of coincidence, but also has a lower degree of wear. At the same time, in order to make the shifting process smoother, most of the gears of automobile gearboxes are helical teeth.
Then, can gears with less than 17 teeth be unable to rotate? This is of course not, but gears with less than 17 teeth will undercut. This will cause more serious gear wear and increase the cost of use. Therefore, most of the time, 17-tooth gears are recommended. It can be said that this proposal is also out of consideration for consumers.
Of course, with the continuous development and progress of global science and technology, there are not too many requirements for the number of teeth. In some high-precision machine tools, there is no difficulty in processing a gear. Therefore, whether future gears will continue to use 17 teeth is still uncertain.