A tensioner is the tensioning device of a belt drive, which adds tension to the belt when the belt’s center distance cannot be adjusted.

The tensioner is generally arranged on the inner side of the loose side, made only with unidirectional bending.  At the same time, the tension wheel should be installed as close as possible to the big belt pulley. This will ensure the belt wheel angle does not decrease too much.

The life range of belt elongation with abrasion and the different thermal expansion coefficients between the engine body and the belt causes the size to change so that the tension of the engine in the operation process is not stable. If the tension is too large, the driving device will make a noise and shorten the life of the belt. If the tension is too small, the belt will easily vibrate and make noise. In addition, the belt will easily wrinkle and break, thus shortening the life of the belt. The tracking performance of automatic vehicles tends to have tension with smaller fluctuation. This reduces the noise of the system effectively and prolongs the life of the belt.