Complete Guide to Transmission Belting

What Are Transmission Belts?

Transmission belts are continuous loop belts set between two ‘pulleys’ to transmit power through the transmission belting into the machinery the belting is situated.

Transmission belting is used across an array of industries, from automotive manufacturing and performance through to industrial belting production and manufacturing, as well as a source of motion

Positive Drive vs Friction Drive Transmission

Fundamentally there are two forms of transmission belting for power transmission. These are either friction drive or positive drive. Friction drive belts utilize the belt’s and pulley’s friction to transmit power. The friction drive belting requires balanced tension to maintain the right friction levels. These are traditionally flat belts.

Positive drive belts will rely on the engagement of what is referred to as ‘teeth’ on the belt within the grooves on the pulley(s). There is no slippage with this transmission belt unless the teeth between the grooves’ jump’.

Different Types of Friction Drive Transmission Belting

Depending on the power transmission requirement, the belt type will be fundamental to either friction or positive drive belts.

Woven transmission belts are used specifically for friction drive belts outside of plastic or rubber drive belts. The types of friction drive belts are typically dropping stamps, flat nylon belts or hair belting.

Drop Stamp Belts

Dock stamp belts (also referred to as ‘hammer belts’) are a type of heavy-duty lifting transmission belt used specifically in the forging industry.

The belt drop hammer is one of many drop forging machine tools used within the industry. How the drop stamp belt is used by rollers that grip the belt connecting it to the ‘ram’. The rollers allow the belt to raise the hammer, which causes the belt to slack. The next stage of the process is pulling apart the rollers, which releases the belt, allowing the hammer to fall using gravitated force to hammer the metal sheet in place.

The drop stamp belt is made from polyester multi-filament and ply yarn, covered by play layers of cotton on the top and bottom of the polyester core layer.

The drop stamp belt is treated with a temperature-resistant coating to increase durability and avoid abrasion during lifting. Treating the media this way gives the drop stamp belt an increased friction property.

The key components of a drop stamp belt are:

Long Lifespan 

Due to the multi-filament yarn, weave construction and temperature resistance coating, a drop stamp belt is extremely durable with high levels of strength. This makes a longer living belt solution perfect for the lifting and forging industries.

Special Impregnation

The temperature resistance impregnation of the polyester filament layer means that the drop stamp belt can perform at much tougher temperatures than other transmission beltings.

High Friction Coefficient

The frictional force derived from the drop stamp belt is greater than rubber or PVC transmission belts. This allows for no sticking and a smoother transition between the rollers of the drop stamp machine.

Hair Belting

Unlike drop stamp belts, hair transmission belts are used within power transmission and are made from a combination of nylon and wool hair woven into the ‘wrap’ ply of the belt before cotton is added to the loom. It is then treated with bitumen impregnated into the cotton for additional strength, power and the prevention of fungus properties.

These transmission belts are woven using the traditional ‘warp and weft’ technique, ensuring a robust and highly durable power transmission belt. Hair belting uses a ‘twisted cord’ edge to avoid fraying from the belt, providing a longer lifespan to the belt.

Hair belting is used across all industries powering the drive shaft and is preferred to other beltings due to the belt’s ability to bite on the pulley, which avoids slippage and power losses. In hotter climates, hair belting performs at a much higher capacity than its compatriot transmission belts.

Flat Nylon Belting

Flat transmission belts are friction drive belts relying on the friction between the belt and pulley to transmit power across the machinery. These belts are used in high-performance areas with smaller pulleys in central areas.

The belt comes in endless and connected forms depending on the requirements of the pulley and power transmission required. Flat belts use tension to maintain the correct level of friction across the belting – this allows for a balanced friction coefficient and transmission of power from the drive shaft through to the pulley.

Flat belts are traditionally manufactured using nylon for short and high-ratio drives, performing better when crowning one pulley larger than the other.

The flat transmission belt relies heavily on alignment; when aligned correctly, the belt’s lifespan increases tenfold. Due to the belting’s lack of grooves, energy loss and wear and tear are minimal.

Flat Belt Drive vs V-Belt Drive

Often, there is a common misconception between flat belt drives and v-belt drives. While both belts are used in friction transmission, ultimately, there are substantial differences in how the belts are executed and performed within the pulley.

Woven Transmission Belts vs Other Transmission Belting

Across transmission belting, multiple materials are used in the execution of friction transmission. These range from woven materials such as nylon, cotton etc. and thermoplastic such as PVC or rubber belting materials.

A true transmission belt manufacturer needs to understand the nuances and differences in performance between positive drive and friction drive transmission belting while also understanding the material best suited to the machinery, drive solution and pulleys.