Engineers must know the knowledge of timing belt

Foreword Timing belt is a product designed by combining the advantages of belt transmission, chain transmission and gear transmission, so it has many advantages. But how to use it correctly, still need to understand the following knowledge points. 01 When to use timing belt Long wheelbase, up to 10m low noise The transmission accuracy is relatively high (generally up to 20, if you want higher, you need to add closed-loop feedback) Speed ??<50m/s Power P<300kw Transmission ratio i<10 Temperature -30-90 degrees Celsius 02 Know the synchronous belt If you want to find more synchronous belt parameters, please click synchronous belt parameters 1 Tooth profile Trapezoid Applicable occasions: occasions with low speed and low power transmission. Advantages: high transmission accuracy and cheap Disadvantages: The tooth root is easy to stress concentration, so the load capacity is low; the noise and vibration are large Arc tooth Applicable occasions: small tooth pitch and small backlash, more suitable for positioning and high torque Advantages: high transmission accuracy, large transmission torque, low noise, can prevent interference during tooth meshing Disadvantages: expensive 02 Material Rubber timing belt Use occasion: mainly transmit power Advantages: high transmission power, high fatigue resistance, long life, Disadvantages: not wear-resistant, large deformation, easy to fall off powder. Polyurethane timing belt Use occasions: mainly transfer sports Advantages: small deformation, high transmission accuracy, less flying debris Disadvantages: not water resistant, poor high and low temperature performance, low load 03 Selection timing belt Explanation Although the steps of synchronous belt selection and calculation of each brand are similar, but there will be certain differences, and many brand synchronous belts have written very detailed how to calculate the synchronous belt of their own brand, so I will not explain it here. When using the model, you can refer to the calculation formula of the corresponding brand. 04 Attention to the design of synchronous belt 1 The parallelism of the axis of the pulley must be guaranteed, otherwise the synchronous belt is easy to run off, or climb up the retaining ring. 2 It must be possible to adjust the preload. The shaft spacing is designed to be adjustable as much as possible. When the shaft spacing is not adjustable, in order to ensure that the synchronization has a certain preload, a tensioner can be used for tensioning. Note: The tensioner should be set on the slack side of the belt. If the tensioner is installed on the outside of the slack side, the diameter> the diameter of the small pulley in the transmission; if it is set on the inside, the number of teeth on the tensioner should be> the number of small pulleys. 3 The transmission device and the shaft must have a certain rigidity, otherwise the load is easily unevenly distributed, aggravating the wear of the teeth and the edges. 4 Excessive twists and turns are strictly prohibited. Whether the timing belt is placed or in use, it should avoid excessive bending, which is easy to cause the tensile layer to break. 5 Avoid direct sunlight. Because the material of the timing belt is mainly rubber or polyurethane, it is not suitable for long-term exposure under the sun, which will accelerate their aging. 6 Design shield. On the one hand, it can protect the safety of the operator, on the other hand, it can also protect the safety of the timing belt. 7 oil-proof. The transmission parts of the synchronous belt with high precision are easy to slip the teeth if they are stained with oil, which causes the load to drop and the transmission position is not accurate.