How to Choose the Right V or Wedge Belt for the Job
When looking to purchase a V or Wedge belt, most people think it’s an easy process that requires little to no thought.
However, since the V belt’s inception in 1917, there has been a large amount of technological advancement, and there are various different kinds of V belt to suit different circumstances. Firstly, we will look at what a V or Wedge belt actually is, what they are used for, and how to decide which variant of belt is the right choice for you.
What are V or Wedge Belts?
A V or Wedge belt is rubber transmission belt that is used in pulley systems. The way it deviates from a traditional flat belt is by the possession of sidewalls that slip into corresponding sheave grooves; this provides a much greater surface area for the belt, which also produces a greater amount of stability.
As the belt operates, the tension in the belt produces a force perpendicular to the top of the V belt, which acts to push the sidewalls against the sheave grooves. This ultimately greatly increases frictional force, and thus allows the belt to carry much greater loads. The rubber material of the belt also allows great flexibility and can be bent around the sheaves in the drive system. All of these features combined give the V belt an advantage over traditional flat belts.
What are they used for?
V or Wedge belts have a wide array of applications. V belts are most commonly used in industrial, agricultural, and lower horsepower appliances. V belts clearly have many different applications, and it mostly depends on the size of the V belt (usually measured by the top width of the belt), the temperature and oil resistance of the belt, and what kind of load is expected to be carried by the belt.
V or Wedge belts typically come in a number of varieties that are suitable for different purposes, thus it is very important to make sure that you are selecting the right belt for the right job. The four main “profiles” or “cross-sections” of V or Wedge Belt are the following.
Classical V belts
Classical V belts are the most commonly used, most often for agricultural and industrial machinery. Temperature resistance is typically between -31F to 158F, but with a limited oil resistance. There are 5 types of classical belt, varying on their top width:
A – 1/2 inch top width
B – 21/32 inch top width
C – 7/8 inch top width
D – 1 ¼ inch top width
E – 1 ½ inch top width
Narrow V belts
Narrow V belts possess angled walls with a steeper gradient than classical V belts. This allows the narrow belts to have increased wedging in sheave grooves, and thus possess a higher load capacity, almost 3 times as much as a classical belt, making them useful in applications with high HP demand and temperatures. Temperature resistance is similar to a classical belt, but with a better resistance to oil. There are 3 types of narrow belt:
3V – 3/8 inch top width
5V – 5/8 inch top width
8V – 1 inch top width
Metric belts are mostly used in industrial applications, such as fan belts or vacuums. Transmission power is as much as 2 times greater than classical belts. Temperature resistance is similar to classical belts, and there are 4 types of metric belt:
Metric SPZ – 10mm top width
Metric SPA – 13mm top width
Metric SPB – 17mm top width
Metric SPC – 22mm top width
Fractional horsepower belts are mostly used for smaller applications such as lawnmowers or leaf blowers. Fractional belts possess a thinner profile and a smaller tensile cord, which makes them more flexible and thus easier to bend around small groove sheaves. Temperature resistance is similar to classical belts, and fractional belts have a good resistance to oil. There are 3 types of fractional belt:
Fractional 3L – 3/8 inch top width
Fractional 4L – ½ inch top width
Fractional 5L – 21/32 inch top width