The main reasons for dynamic loads generated by chain sprockets and chain drives during operation are

(1) The chain speed and the angular velocity of the driven sprocket vary periodically, resulting in an additional dynamic load. The greater the acceleration of the chain, the greater the dynamic load will be. The acceleration of the chain is

It can be seen thatSprocketsThe higher the speed, the larger the chain pitch and the smaller the number of teeth of the sprocket, the higher the dynamic load will be.

(2) The chain speed varies periodically along the vertical direction, which causes the chain to vibrate laterally, and this is one of the reasons for the dynamic load of the chain drive.

(3) The instant the chain link enters the sprocket, the link andSprocketsWheel The teeth are engaged at a certain relative speed, the chain and the teeth will be impacted and additional dynamic load will be generated. As shown in Figure 6.11, according to the principle of relative motion, the chain sprocket is regarded as stationary, and the chain link enters the wheel teeth with angular velocity -w and generates impact. This phenomenon increases with the increase of the sprocket speed and the increase of the chain pitch. It makes the transmission generate vibration and noise.

(4) If the chain tension is not good and the chain is slack, in the case of starting, braking, reversing and load change, it will produce inertia shock and make the chain drive produce great dynamic load.

Due to the dynamic load effect of chain drive, chain drive is not suitable for high speed.