Technical information on Timing belts
The material and cabling of your Belt will depend on your application.
To transmit power: fast, constant speed on small Pulleys.
To transport products: slow speed and transport on the back of the belt.
The stresses on the Belt are therefore not the same.
Power transmission
The Poly Chain® type Belt has been designed for high-torque, low-speed transmissions. The Belt is reinforced with carbon fibre.
It guarantees dimensional stability and ensures perfect meshing of the Belt on the Pulley.
The advantages of this Polyurethane Synchronous belts :
- excellent mechanical strength of the tooth
- very good abrasion resistance
- the best thermal resistance of all power transmission belts: it can withstand temperatures from -54°C to 140°C, compared with only -20°C to 100°C for a Neoprene driving belt.
Nevertheless, the Neoprene driving belt offers very high fatigue strength (Neoprene being a softer, more flexible material than PU). However, the abrasion resistance of a Neoprene belt will be more moderate than that of a Polyurethane belt.
The specific manufacturing process for Polyurethane Synchronous belts also offers good resistance to oils, acids and chlorine. The most fire-resistant belt is Poly Chain®.
Transport
The polyurethane conveyor belt has the same technical characteristics as a belt (sleeve) made from the same material.
| APPLICATION | POWER TRANSMISSION | TRANSPORT | ||
|---|---|---|---|---|
| Material : | Neoprene | PU (sleeves) | PU (Poly Chain®) | PU |
| TEMPERATURE | -20 to 100°C | -5 to 70°C | -54 to 140°C | -5 to 70°C |
| Oil resistance : | Average | Excellent | Good | Excellent |
| Acid resistance : | Low | Good | Very good | Good |
| UV resistance : | Good | Poor | Good | Low |
| Fire resistance : | Very good | Good | Excellent | Good |
| Chlorine resistance : | Poor | Good | Very good | Good |
| Fatigue strength (bending) : | Excellent | Very good | Good | Very good |
| Hardness : | Medium | High | Maximum | High |
| Mechanical strength of the tooth : | Good | Very good | Excellent | Very good |
| Abrasion resistance | Average | Good | Excellent | Very good |
Timing belt Cords
There are 4 types of Cords in driving belts:
Fibreglass - Steel - Kevlar® or Aramid and Carbon
Fibreglass Cords: excellent fatigue strength and very good resistance to moisture; like carbon tensile strength rope.
Steel Cords: excellent tensile strength and very low elongation compared to fibreglass ropes.
| APPLICATION | POWER TRANSMISSION | TRANSPORT | |||||
|---|---|---|---|---|---|---|---|
|
Material : |
Fibreglass |
Steel |
Kevlar® |
Carbon |
Steel |
Kevlar®Steel |
HF steel |
|
Tensile strength : |
Average |
Excellent |
Good |
Very good |
Excellent |
Good |
Very good |
|
Fatigue strength : |
Excellent |
Average |
Average |
Good |
Average |
Average |
Good |
|
Resistance to humidity : |
Very good |
Average |
Good |
Very good |
Average |
Good |
Average |
|
Min. diameter : |
Very good |
Medium |
Average |
Good |
Average |
Average |
Good |
|
Pinch resistance : |
Medium |
Weak |
Low |
Low |
Low |
Low |
Low |
|
Relaxation : |
Medium |
Excellent |
Average |
Very good |
Excellent |
Average |
Excellent |
|
Stability over time (elongation): |
Average |
Excellent |
Average |
Very good |
Excellent |
Average |
Excellent |
|
Stiffness/ Rigidity : |
Low |
High |
Good |
Very good |
High |
Good |
High |
ANSWERS TO YOUR QUESTIONS ABOUT TOOTHED BELTS
Why use a Belt with Kevlar® rather than steel Cords?
There are a number of reasons for choosing to use Kevlar® instead of steel:
- Presence of a metal detector close to the Belt
- Application in the food industry
- Kevlar® does not deteriorate in a damp environment
- At high speeds, Kevlar® will not generate any electrical interference
Why use a polyurethane Timing belt instead of another type of timing belt?
- Unrivalled abrasion resistance compared to other plastics.
- Polyurethane does not shed particles through abrasion, which can contaminate essential components of the product or the environment.
- Highly elastic and resilient, helping it to absorb shocks.
- Maintains flexibility over a significant temperature range (from -30°C to 80°C; short-term to 120°C).
- Does not harden or degrade as quickly as neoprene.
In what chemical environments can polyurethane Belts be used?
Polyurethanes are generally resistant to ozone, hydrocarbons, greases, oils and ambient temperature. Belts are generally attacked by concentrated acids, chlorine compounds, hydrocarbons and high-temperature water. Certain chemicals known to attack polyurethane can be used with PU belts depending on the relative concentration, temperature and duration of chemical exposure. We are unable to control the environment under which a belt is used, so it is up to the customer to determine the suitability of the belt under these exact conditions.
Why use nylon on the tooth or back of the belt?
Nylon on the teeth is used on neoprene belts to improve the shear strength of the tooth, promote sliding during meshing and increase abrasion resistance.
Polyurethane belts use a nylon fabric on the teeth to reduce the coefficient of friction of the belt for conveying and, in some cases, to reduce the noise generated between the belt and the pulley in a relatively high-speed application.
The nylon on the back of the polyurethane belt is used to reduce the coefficient of friction if the product has to slide on the back of the belt or for other applications where low friction is desirable.