What Are Power Transmission Belts?
The clue to what a transmission belt does is in the name—“transmission” means transferring mechanical power from one place to another. In this case, transmission belts transfer power between pulleys, including a powered driver pulley and one or more driven pulleys.
One of the many benefits of using a pulley system is that it can act as a sort of fail-safe should the drive jam. When shocks occur, the belt may fall off or break, thus preventing a transfer of extreme power to the rest of the machine. Without such a system, the jam could end up damaging more of the machine, making expensive repairs necessary.
Why Use Urethane Belts?
Urethane belts (or “polyurethane” belts) are one of the best alternatives to rubber. Prior to their invention, rubber was basically the only option for transmission belts.
No Dusting
Unfortunately, rubber tends to break down over time due to friction. It leaves tiny rubber shavings all over the inside of the machine, which can eventually cause buildup and maintenance problems. Urethane, on the other hand, doesn’t create dust as it ages.
Sunlight Resistance
Unlike urethane, rubber tends to break down the longer you expose it to sunlight and air. The process is invisible to the naked eye, but it’s extremely powerful. Like it does to many things, ultraviolet light from the sun penetrates the rubber and slowly breaks down its molecular structure, breaking apart the chains forming the rubber’s organic polymers.
Longer Lifespan
Because urethane resists UV radiation and doesn’t break down over time, it’s a far better choice than rubber for transmission belts. Part of this is also due to urethane belts’ construction. Manufacturers typically have to mix rubber with nylon fibers in order to create strong belts, but urethane belts have a more cohesive structure.
Installing a Urethane Transmission Belt
Even though they have a long lifespan, urethane belts will wear out eventually. Here’s a guide to help you replace the transmission belt in cars and trucks, since those are among the most common places to find a power transmission belt.
Many of the types of belts used in cars and trucks also appear in other machines, like bandsaws, conveyor belts, and HVAC systems. The belt types listed below offer descriptions that are relevant to many power transmission systems.
Vehicle Transmission Belts
Many belts in vehicles are power transmission belts. These include V-belts, serpentine belts, and timing belts (sometimes called camshaft belts). The exact replacement method will depend on your vehicle, but you typically need to put it into the service position first. You may also need two people working from above and below the vehicle for quicker replacement.
V-Belts
In older cars, most engines use multiple V-belts to drive things like the A/C compressor, alternator, and power steering. V-belts get their name because of their shape, which looks like a “V” on the ends. V-belts work by wedging into their pulleys to create torque.
One of the benefits of an older system is that when one of the belts breaks, the entire engine isn’t shut down. Since there are multiple belts, you only need to replace the one that’s broken.
Serpentine Belts
Newer cars tend to have one long belt that snakes through multiple pulleys—thus the name “serpentine belt.” Serpentine belts can be easy or difficult to install, depending on the vehicle’s design. You will most certainly want two people working on this replacement since there are so many pulleys to wind the belt around.
Timing Belts
The timing belt is one of the most important belts in the entire vehicle. It helps synchronize the camshaft and crankshaft so that the engine’s pistons and valves alternate correctly. Because the pistons and valves can’t exist in the same space at the same time, the timing belt’s job is vital to keeping an engine working properly.
Timing belts look different from V-belts because they are flat with large grooves on one side. These grooves lock into matching slots on the pulley wheels, ensuring proper tension and torque. In worn-out belts, you may notice some of these grooves are missing or damaged.
Maintaining Your Urethane Transmission Belts
If you want your belts to last as long as possible, then you need to properly maintain them. Here are some tricks to help get the maximum lifespan out of your polyurethane belts.
Keep the Drive Clean
Even though urethane belts don’t create dust like rubber belts do, it’s possible for dust or other particles in the air to get inside the drive. Removing these excess particles will help prolong the life of your belts.
Replacing Worn Out Sheaves
Sheaves are the grooved wheels that make up the various parts of a pulley drive system. When the grooves wear out, they can damage the belts and shorten their lifespan. To check your system’s sheaves, you may want to invest in a measuring tool so you can keep an eye on how much the sheaves have worn down.
When you’re checking your drive’s sheaves, keep an eye out for any notches or sharp points along the belt groove. These small imperfections can actually damage your belts, causing tears and other problems.
Ensure Proper Belt Coverage
Some belts, like the timing belt in a car engine, usually have a protective cover that keeps off dust, oil, and grime from the rest of the car’s interior. Always check that this cover is properly fitted and has no cracks. Oil from other systems dripping on the timing belt can lead to corrosion over time.
Finding Replacement Urethane Belts
If you’re looking to replace worn-out urethane belts in your vehicle, HVAC system, conveyor system, or bandsaw, check out our inventory at Texas Belting and Supply. We have an amazing variety of belts in all shapes and sizes. Here are some of the other specifications we offer:
- Flame-retardant
- Food grade
- Reinforced
- Anti-static
- Heavy duty
- Electro conductive
We hope this guide to installing and maintaining urethane power transmission belts has been helpful. Don’t hesitate to reach out with any questions you have.
