The automatic belt tensioner Timing

The main elements of the automatic tensioner (Fig. 3.6) the timing belt is spring and damper.

If the belt tension weakens, the plunger under the action of a spring and forced out oil flows through the check valve to the other side of the plunger as long as the pressure on both sides are equalized.

If the belt tension increases, the oil is squeezed out through the channel back behind the plunger as long as the pressure on both sides are not aligned. This maintains a uniform and correct belt tension independently of temperature.