Gear transmission is the most widely used transmission form in mechanical transmission. Its transmission is more accurate, high efficiency, compact structure, reliable work, long life.

Advantages: compact structure, suitable for short-distance transmission; Wide applicable circumferential speed and power range; Accurate and stable transmission ratio and high efficiency; High working reliability and long service life; Transmission among parallel axes, intersecting axes at any angle and staggered axes at any angle can be realized. 

Disadvantages: high manufacturing and installation accuracy and high cost; Not suitable for long-distance transmission between two shafts; No overload protection. 

● worm gear and worm drive

 It is suitable for the motion and power between two axes which are vertical and disjoint in space.

Advantages: large transmission ratio and compact structure and size.

 Disadvantages: large axial force, easy heating, low efficiency, only one-way transmission.

● belt drive 

Belt drive is a kind of mechanical drive that uses flexible belt stretched tightly on pulley to move or transmit power. Belt drive usually consists of a driving wheel, a driven wheel and an endless belt stretched tightly on the two wheels.

Advantages: it is suitable for transmission with large center distance between two shafts, and the belt has good flexibility, which can alleviate impact and absorb vibration; Slip during overload to prevent damage to other parts; Simple structure and low cost.

 Disadvantages: the outer dimension of the transmission is large; Need to expand the device; Due to slippage, a fixed transmission ratio cannot be guaranteed; The belt has short service life and low transmission efficiency. 

● chain drive

 Chain drive is a transmission mode that transmits the movement and power of the driving sprocket with special tooth shape to the driven sprocket with special tooth shape through chain. Comprises a driving chain, a driven chain and an endless chain.

Advantages: compared with belt drive, it has no elastic sliding and slipping phenomenon, accurate average transmission ratio, reliable operation and high efficiency; Large transmission power, strong overload capacity and small transmission size under the same working condition; The required expansion force is small, and the pressure acting on the shaft is small; Able to work in harsh environments such as high temperature, humidity, dust and pollution. 

Disadvantages: It can only be used for transmission between two parallel shafts; High cost, easy wear and elongation, poor transmission stability, and additional dynamic load, vibration, impact and noise will be generated during operation, so it is not suitable for rapid reverse transmission. 

● gear train transmission

 Features: The transmission composed of more than two gears is called gear train. Gear transmission can be divided into ordinary gear transmission and planetary gear transmission according to whether there are gears with axial movement in the gear train, and the gears with axial movement in the gear train are called planetary gears.

Suitable for transmission between two shafts far apart; It can be used as a transmission to realize variable speed transmission; A larger transmission ratio can be obtained; Realize the synthesis and decomposition of motion.