function of the tensioner is to adjust the tightness of the timing belt. The belt is easily stretched over time, and the tensioner can automatically adjust the tension of the belt, so that the belt runs more smoothly, with less noise, and can prevent slippage. The speed of the tensioner wheel is high, and the speed of the tensioner wheel is about 3000RPM when the engine is idling. The engine is at 3000RPM, and the speed of the tensioner is more than 10000RPM. The operating ambient temperature is 90°C. In such a harsh working environment, the tensioner is a vulnerable part of the auto parts. When the engine timing belt is replaced, the tensioner also needs to be replaced to avoid worries. The tensioner is also a safety part of auto parts. Once the tensioner fails, the belt breaks and the car loses power, which will cause major safety accidents.