But many people say that the number of teeth in a gear cannot be less than 17. The source of this number should start with the processing method of gears. Among many processing methods, generating method is the most widely used.
When workers process gears in this way, undercutting often happens. The bad influence is that the thickness of gear tooth root becomes soft, and then the bending resistance is reduced, so the stability will be damaged during operation. To put it bluntly, undercut refers to the intersection of meshing angle and gear meshing line, which exceeds the limit meshing point of cutting off the gear. This phenomenon is undercut.
Finally, through the research of employees, it is found that the reason for this phenomenon is that there are too few teeth in gears. If the number of gear teeth exceeds 17, the undercut phenomenon can be well prevented.
If the total number of gears is less than 17, is it really impossible to rotate? But in our daily life, we often see gears with the number of teeth less than 17. Can we say that these gears are "fake" and can't turn? The answer is naturally not like this.
Generally, under the premise of reaching the bending strength of the transmission gear, we will choose to reduce the number of teeth and get a more compact structure. Therefore, at this time, a slight undercut is allowed. Naturally, this one also has a certain degree of teeth, generally 14.
In fact, from another point of view, the number of teeth of 17 is to better prevent the undercutting phenomenon of gears, but the undercutting phenomenon is also closely related to the machining method. If we improve or change a machining method, such as forming or displacement machining, undercutting will not occur easily, so the gear will not be limited by the data of 17.
In addition, even if the gear is undercut, the gear will become soft during the whole working process, so everyone can increase the thickness of the gear and achieve the practical effect of daily application. The gear without undercut has stronger practical effect and longer service life. Regardless of service life and high application efficiency, no matter how many teeth there are, gears can actually rotate.
The raw materials of gears, common gears, are basically rigid steel raw materials. Because of the working characteristics of gears, they must have high wear resistance, pitting corrosion resistance and fracture resistance. Therefore, the first rule of making raw materials is that the journal should be hard and the tooth core should be tough. Of course, there are some exceptions. For example, in some micromotors and electronic equipment, plastic gears, such as polyester and polyoxymethylene, are often used. Its highest characteristics are convenient production and manufacturing, low cost and strong corrosion resistance, and now it is widely used in many mechanical equipment industries.