The synchronous belt pulley is a kind of hub part, and its relative size is generally large. The manufacturing process is generally dominated by casting and forging. Generally, the design with large size is cast, and the materials are generally cast iron (good casting performance), and rarely cast steel (poor casting performance of steel); Generally, the small size can be designed as forging and the material is steel. The selection of various indexes and materials of synchronous belt pulley is based on the selection principle of minimizing raw materials, feasible technology and ultra-low cost on the premise of meeting the use requirements! Synchronous pulley is mainly used for long-distance power transmission, such as small diesel power output, agricultural vehicles, tractors, automobiles, mining machinery, machining equipment, textile machinery, packaging machinery, lathes, forging machines, power transmission of some small horsepower motorcycles, power transmission of agricultural machinery, air compressors, reducers, reducers, generators, Gin, etc.
The advantages of synchronous pulley drive are: synchronous pulley drive can alleviate the load impact; The synchronous pulley drive runs smoothly, with low noise and vibration; The structure of synchronous pulley drive is simple and easy to adjust; The manufacturing and installation accuracy of synchronous belt pulley is not as strict as meshing transmission; The synchronous pulley drive has the function of overload protection; The adjustment range of the center distance between the two axles of the synchronous belt pulley drive is large. The disadvantages of belt drive are: the synchronous pulley drive has elastic sliding and slipping, low transmission efficiency and can not maintain accurate transmission ratio; When the synchronous pulley transmission transmits the same large circumferential force, the outline size and shaft pressure are larger than those of meshing transmission; The service life of synchronous pulley drive belt is short. The diameter and other dimensions of the synchronous pulley of various mechanical equipment are matched according to the reduction ratio and designed according to the working speed and motor speed. Working speed / motor speed = driven wheel diameter / driving wheel diameter * 0.98 (sliding coefficient). If steel synchronous pulley is used, the linear speed shall not be higher than 40m / s. if cast iron is used, the linear speed shall not be higher than 35m / s. The conversion ratio between motor speed and synchronous pulley diameter, speed ratio = output speed: input speed = load synchronous pulley pitch diameter: motor synchronous 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. Y Z a B C D E, the groove depth on the reference line is h = 1.6 2.75 3.5 4.8 8.1 9.6 respectively. The pitch circle diameter of synchronous belt pulley is the theoretical diameter of the pitch line position of synchronous belt pulley, 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 synchronous belt 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 outer diameter of the pulley of a or spa is 80mm. If it is smaller 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.
