Transmission advantages of pulley

The advantages of belt pulley transmission are: the belt pulley transmits kinetic energy to mitigate the impact of load; The belt pulley drives smoothly, with low noise and vibration; The structure of belt pulley transmission is simple and easy to adjust; Pulley drive is not as strict as meshing drive for the manufacturing and installation accuracy of pulley; The belt pulley transmission has the function of overload protection; The adjustment range of the center distance between the two shafts driven by the belt pulley is large. The disadvantages of belt transmission are: the pulley transmission has elastic sliding and slipping, the transmission efficiency is low and the accurate transmission ratio cannot be maintained; When the belt pulley transmission transmits the same large circumferential force, the outline size and the pressure on the shaft are larger than that of the meshing transmission; The service life of pulley drive belt is short. The diameter and other dimensions of the pulley of various mechanical equipment are matched according to the reduction ratio and designed according to the working speed and the speed of the motor. Working speed / motor speed = driving wheel diameter / driven wheel diameter * 0.98 (sliding coefficient). If steel pulley is used, the linear speed shall not be higher than 40m / s. if cast iron pulley is used, the linear speed shall not be higher than 35m / s. The conversion ratio between motor speed and pulley diameter, speed ratio = output speed: input speed = load pulley pitch diameter: motor pulley pitch diameter. The pitch diameter is the same as the reference diameter. Diameter - 2H = pitch diameter, h is the groove depth on the reference line, and H is different for different models of V-belt. Yzabcde, the groove depth on the reference line is h = 1.622.753.54.88.19.6 respectively. Pulley pitch diameter is the theoretical diameter of pulley pitch line position, which is a bit like the indexing circle diameter of gear It is generally expressed by PD, and the outer circle is generally expressed by OD The conversion formulas of pitch circle and outer circle of different groove types are different. Generally, we can easily measure the outer circle of the pulley and calculate the pitch circle according to the formula SPZ:OD=PD+4; SPA:OD=PD+5.5; SPB:OD=PD+7; SPC:OD=PD+9.6。 The minimum outer diameter of the pulley of a or spa is 80mm. If it is less than this size, especially at high speed, the belt is prone to delamination and cracks at the bottom. SPZ belt, small wheel not less than 63mm. At the same time, pay attention to the installation method and tension of the belt. If it is too small, it is easy to slip, and if it is too large, it is easy to damage the belt and bearing.