Gear transmission is the most common mechanical transmission in modern machines. It is a main form of transmission of machine power and motion and an important basic part of mechanical products. Compared with belt, chain, friction, hydraulic and other mechanical transmission, it has a series of characteristics, such as large power range, high transmission efficiency, high peripheral speed, accurate transmission ratio, long service life, long structure size and small structure size. Therefore, it has become an indispensable transmission part of many mechanical products, and it is also the transmission form with the largest proportion in the machine. In recent years, although the manufacturing technology and electric transmission technology of other mechanical parts have made great progress, the transmission form that dominates in production is still gear transmission. Gear drive has the following advantages and disadvantages:
Advantages include:
1) The instantaneous transmission ratio is constant and the working stability is high;
2) The non-circular gear is adopted, and the instantaneous transmission ratio can be designed according to the required change rule;
3) Wide range of transmission ratio variation, suitable for decelerating or increasing speed transmission;
4) The peripheral speed range of gear is large.
5) The transmission power range is large and the bearing capacity is high.
6) The transmission efficiency is high, especially the cylindrical gear pair with high precision.
7) Compact structure, such as the use of planetary transmission, small tooth difference transmission, or harmonic gear transmission, can make the components smaller and become coaxial transmission;
8) Easy to maintain.
Disadvantages include:
1) Vibration, impact and noise during operation, and generate dynamic load;
2) No overload protection;
3) When the precision of gear cutting is required to be high or with special tooth shape, high precision machine tools, special cutters and measuring instruments are needed to ensure that the manufacturing process is complex and the cost is high