The driving advantage of pulley
When overloaded, the belt will be skidded on the belt, preventing weak parts from being damaged and protecting the safety. (4) does not guarantee accurate ratio. The pulley material is cast iron, etc. The characteristics of the chain: (1) compared with gear transmission, it can be far apart in the center of the two shaft under the condition of transfer movement and power; To work in low-speed, heavy-duty, and high-temperature conditions and in dusty and dusty environments; Compared with the belt transmission, it can guarantee the accurate average transmission ratio, the transmission power is larger, and the force acting on the shaft and bearing is smaller; The transmission efficiency is higher, which is generally 0.95 ~ 0.97. When the hinge of the chain is worn down, the pitch of the pitch becomes large and causes the shedding phenomenon. 6. Installation and maintenance requirement is higher. The chain material is generally constructional steel, etc. The characteristics of gear transmission: (1) can guarantee the instantaneous transmission ratio is constant, high stability, accurate and reliable transmission motor; The range of power and speed of transmission; The structure is compact and reliable, which can realize a large transmission ratio. High transmission efficiency, long service life; The manufacturing of the gears and the installation requirements are higher. The gear materials are usually cast iron and so on.
The advantages of pulley drive are: the belt wheel drive can mitigate the load impact. The belt wheel drive is smooth, low noise and low vibration. The structure of the pulley drive is simple and easy to adjust. The belt wheel's manufacturing and installation accuracy is not as strict as meshing drive; The belt wheel drive has the function of overload protection; The two shafts of the pulley drive are larger in range. The disadvantages of belt drive are: the belt wheel drive is flexible and smooth, the transmission is less efficient and cannot maintain accurate transmission ratio. When the belt wheel drives the same large circle force, the size of the outline and the pressure on the shaft are greater than the meshing drive. The belt has a shorter life span. The diameter of the belt wheel of various kinds of mechanical equipment is based on the speed of deceleration, and the speed of the machine is designed according to the speed of the machine.
Work speed/motor speed driving wheel diameter/driven wheel diameter * 0.98 = (sliding coefficient), such as using steel belt pulley for materials, for linear velocity is not higher than 40 m/s, such as the use of cast iron material, require linear velocity is not higher than 35 m/s, motor speed and pulley diameter conversion ratio, speed ratio = output rotational speed, input speed = load pulley pitch diameter, pitch circle diameter of the motor pulley. Pitch diameter and benchmark is the same diameter, diameter - 2 h = pitch diameter, h is on the line groove depth, different models of V belt h is not the same, A B C D E, Y, Z line groove depth respectively in 2 h = 1.6 1.6 3.5 4.8 8.1 2.75. Pulley pitch diameter is pulley diameter section line theory, a bit like gear pitch circle diameter. Generally expressed in PD, cylindrical generally expressed in OD. Different type slot pitch circle and cylindrical conversion formula is different, generally we tend to measure to the pulley cylindrical, in according to the formula to calculate the pitch circle. SPZ: OD = PD + 4; SPA: OD = PD + 5.5; .spb: OD = PD + 7; SPC: OD = PD + 9.6. The minimum diameter of A or SPA is 80mm, if it is less than that, especially at high speed, the belt is prone to cracks and cracks in the bottom. The SPZ band, the small wheel is not less than 63mm. Also pay attention to the belt mounting technique and the tension, too small and easy to slip, too big to damage the belt and bearing.
