- There are many different mechanisms by which drive belts generate noise.
- Produced from the impact between timing belt and pulley. The resultant displacement of the belt will propagate away from the impact point. The impact will result in the pulley vibrating and hence radiating noise. The design of the pulley should be such that the first mode of vibration is greater than the impact frequency over the operating speed range of the pulley. The impact frequency can be calculated from the rotational speed of the pulley and the number of teeth on the pulley.
- Belt vibration
- Transverse and torsional belt vibration (goose noise or whine).
- Air pumping
- Flow of air between the belt and pulley. The air will be squeezed out when the belt teeth engage the pulley and air will rush in when the belt disengages from the pulley.
- Friction between the pulley and timing belt.
- Pulley vibration
- Due to fluctuating torque.
See also: Belt Drive.