Type and structure of drive belt

　　Drive BeltIt is also called belt transmission. As a type of mechanical transmission, it often uses one or several belts to cover the two wheels. The two wheels are respectively installed on the driving shaft of the transmission belt. And on the transmission shaft, and then the friction between the transmission belt and the two wheels is used to transmit motion and power. The transmission belt can rely on the friction generated by the pulley and the belt during the tensioning process, the power generated by one is thus transmitted to the other so that the transmission belt can be used for transmission of a larger distance between the working machine and the power machine.

Because the belt itself is elastic, it can buffer the impact during the transmission process, making the transmission more stable and reducing vibration. However, the transmission belt cannot guarantee a strict transmission ratio, that is, the speed of the driving wheel per minute. The ratio of the revolutions per minute of the driven wheel is not fixed. When the bed moving belt encounters obstacles or is overloaded, the transmission belt will slip on the pulley, thus preventing tendon damage. The transmission method of the transmission belt is relatively simple, and it is also relatively easy to maintain. It can also be disassembled and replaced, and the working cost is relatively low. However, because the belt is easy to slip on the pulley, the efficiency of using the transmission belt is still relatively low, and because the durability of the belt itself is relatively poor, if it is used for a long time, it will gradually stretch, so everyone needs to adjust the length of the belt at any time after a certain period of time during the use process.

According to the cross-sectional shape of the transmission belt, we can divide it into triangular belt transmission, flat belt transmission and round belt transmission. The section of the flat belt is a flat rectangle, the surface of the pulley is a smooth cylindrical shape, and when the belt works on the pulley, its inner surface is a working surface. The triangle belt profile is trapezoidal, and the triangle belt and the pulley groove are in contact on both sides, so its side is the working surface. Under the same Q force, the positive pressure generated by the V-belt on the working surface is larger than that of the flat belt. Therefore, when other conditions are the same, the V-belt can transmit a large circumferential force. Round belt is generally only suitable for small power transmission, such as sewing machine and some equipment on the transmission device. Triangular belt drive is more widely used than flat belt drive, and the calculation principle of the two is basically the same.

　　Drive BeltIt is composed of a driving wheel, a driven wheel and an endless belt tensioned on two pulleys; due to tension, a pressing force is generated in the contact part of the belt and the pulley. When the driving wheel is running, it drives the belt by friction, and the belt drives the driven wheel to run. In this way, the power of the driving shaft is transmitted to the driven shaft.

Cut three samples with a length of 250 mm from one PJ V-ribbed belt, and mark a marking line with a spacing of 100mm at the middle position of the PJ V-ribbed belt. When more than three samples cannot be taken from one PJ V-ribbed belt, samples can be cut from the same batch of PJ V-ribbed belt, but must be indicated in the report. 7.4.2 High temperature resistance test method
Place the sample at 100 ℃ ± 2 ℃ for 96 h ± 1 h and then take it out. After standing at laboratory temperature for more than 2h, bend it along a cylinder with a diameter of 20 mm at a contact angle of at least 90 °.