Transmission is a key link in the energy conversion of motor products. Common transmission methods include gear transmission, coupling transmission and belt transmission. When coupling transmission is used, the towed equipment and the motor have the same rotation speed, that is, the angular velocity of the two is the same; while when gear or belt transmission is used, there is a speed change relationship between the two.
Belt drive is suitable for situations where the distance between the motor and the center of the shaft of the driven equipment is far. The transmission process is relatively smooth and there is not much noise. It has certain buffering and vibration absorption characteristics. Especially in the case of overload, the transmission belt will slip on the pulley, which provides a certain overload protection for the motor.
However, belt drives also have their performance limitations, and have the following defects: the tightness of the belt directly affects the transmission ratio, and the transmission accuracy is not high; during the transmission process, the motor shaft extension and the equipment shaft extension are both subject to bending moments, and high mechanical strength requirements are placed on the rotating shaft, otherwise there will be serious problems with shaft extension breakage; during the operation of the motor and equipment, the belt will age to varying degrees and its elastic properties will change. If it is not inspected and maintained in time, the belt will slip more seriously, directly affecting the stable operation level of the motor, especially for the situation where multiple belts are acting at the same time. If one or more of the belts slip, it will cause frequent failures during the operation of the equipment.
From the speed performance analysis of belt transmission, the theoretical match of the linear speeds of the two can be achieved. According to the diameter difference between the driving wheel installed on the motor shaft and the driven wheel installed on the equipment shaft, the constant speed, increasing speed and decreasing speed transmission of angular velocity can be achieved: when the driven wheel diameter is larger than the driving wheel diameter, it is in the decreasing speed state, otherwise it is in the increasing speed state; and when the driving and driven wheel diameters are equal, it is a typical constant speed dragging state.
As for the size of the driving wheel of the motor, when the wheel diameter is larger, the motor shaft extension will be subjected to greater torque under the same belt tension. If the belt is tight enough, the required mechanical power can be output stably and reliably; when the belt is too loose, the product of the belt tension and the pulley diameter does not match the rated torque of the motor, and slippage will occur. However, the belt tensioning force cannot be too large, otherwise the bending moment of the motor output shaft will be too large, and the stress in the shaft section will exceed the allowable limit stress, resulting in shaft bending or breaking.
From some actual cases of belt transmission, it is found that during equipment maintenance, only the damaged belt is replaced when replacing the belt, and as a result, only the new belt works, and the other belts are in a loose state, resulting in violent shaking during dragging, and the equipment cannot operate normally. Therefore, when it comes to belt replacement, remember to replace them at the same time to ensure that all belts have equal tension and work normally.
From a theoretical analysis, the specific transmission ratio of pulley transmission can be set according to the actual operating requirements. However, from the analysis of actual application effects, relatively matching transmission ratios, and transmission belt types and relative distance dimensions that have been verified by a large number of applications will result in longer belt life and higher transmission efficiency.
Post time: Feb-17-2025