Timing Belt Noise Causes and Solutions

What causes timing belt belt noise and how to reduce it? There are 4
common causes for belt noise. They are by no means the only causes of noise but
they are a good starting point.

They are:

• Impact of the belt teeth on the pulley
• Air Displacement by the teeth on the pulley
• Friction between the belt and the pulley
• Resonance frequencies

Impact Noise

You’ll find impact noise and friction noise are more common at lower belt speeds whereas air volume displacement is common at higher RPMs.

Problem

Impact noise is when the belt tooth engages with the pulley.

Solution

1. To solve this problem, you can minimize the polygonal effect with continuous tooth engagement using belts such as ARC Power.
2. Reduce the belt width or used a lower tooth.
3. Switching to a belt such as AT10move-series which has a lower tooth face and a friction reducing coating will reduce noise.

Friction Noise

Friction noise is not only a nuisance, but it is damaging to the belt over time.

Problem

If there is a meshing differential between the belt and the pulley you will get friction noises.

Solution

1. When you use BRECOflex timing belts and pulleys together, we guarantee perfect meshing.  So as long as you are using the correct belt with the correct pulley, timing belt noise from friction should not be an issue.
2. For friction noises at lower RPMs, we recommend that you minimize the coefficient of friction by using a nylon covering on the tooth side, which we refer to as a PAZ. You can also opt for a dry lube or silicone grease which can be very effective.
3. Another solution for friction noise is to choose ARC Power also known as BATK timing belts. The dynamics of the belt reduces friction and the curved technology vents air toward the belt edges. Furthermore, this belt eliminates flange friction because it is self-tracking.

Air volume displacement

Air volume displacement has a distinct sound and if often described as sounding like air escaping from a balloon.

Problem

Air volume displacement is caused when there is a space between the belt and the pulley. This type of timing belt noise will increase with belt speed.

Solution

1. You can maximize air permeability which is especially helpful with high-speed drives. Ways to achieve air permeability is by using multiple smaller belts or by cutting air grooves on the pulley.

Resonance

Problem

Resonance happens when you have overlapping vibrations in your system. Resonance is dependent on belt width.

Solution

1. You can change your driving RMP and try to change variables to quite the drive. You can also opt for a belt such as BATK to reduce polygonal effect and belt oscillation.

For an example of a belt noise problem and solution, please watch the video.

When dealing with issues of noise, examine each of the above variables as a possible cause. It is important to note that noise could be indicative of a bigger issue that could cause damage to your belt, pulley or drive over time.  If you need assistance in determining the cause and solution for our belt noise, please contact a BRECOflex applications engineer.