What is Belt Drive?
A belt drive is a frictional drive that uses pulleys and an elastic belt to transmit power between two or more shafts. It is usually driven by friction, although it can also be a positive drive. It can function at various ranges of speed and power needs. It's also really effective. When it comes to cost, a belt drive is substantially cheaper than gear and chain drives. It is less expensive to install and maintain. When compared to chain-drive sprockets, belt drive sheaves or pulleys are less likely to wear out over time.
Power is transmitted from the driver pulley to the belt and from the belt to the driven pulley with the help of friction. The power transmitted by belt drive depends upon friction between the belt and pulley surface. Once the limiting value is exceeded, slipping of the belt occurs.
Types of Belts
Belt designs, like belt drives, have been customized for specific needs. In different scenarios, each of them has an advantage over the others. The following five are the most common belt types used in belt drives.
- Round belt
- Flat belt
- Toothed belt
Round Belt Drive
Round belts have a circular cross-section and are designed to fit into U or V-shaped pulley grooves. round belts are ideal for applications where belts are expected to twist and turn a lot while contacting several pulleys. These belts may transmit power and provide friction from any region of their round surface by their very nature. Other advantages of round belts include:
- Available in different sizes, colors, and textures
- There is no fraying.
- Strong and long-lasting
- Cleaning is simple.
- Fit different pulley shapes
- Can be strengthened for added durability
- Abrasion resistance and UV resistance can be enhanced as necessary.
Flat Belt Drive
One of the most prevalent types of industrial belts are flat belts. The rectangular cross-section of these belts allows them to operate by resting on top of flat pulleys. Depending on the design, they transmit power from one or both sides. Flat belts were the first application of a leather belt. However, as new materials such as rubber and synthetic polymers have been discovered, leather belts have decreased.
Flat belts have the following advantages:
- At high belt speeds, a flat belt can deliver significant power.
- Operation with minimal noise
- High efficiency (up to 98%)
- Because of the narrow bending cross-section, there is less bending loss.
- High flexibility
- No need for groove
- long service life due to their ability to handle dust and filth.
- It can be reinforced for increased strength.
Flat belts aren't ideal for applications with short distances between pulleys. V-belts have mainly taken their place in these applications. V-belts are, in fact, the most popular belt type nowadays. The cross-section of a V belt is trapezoidal (V-shaped), and it fits into a corresponding groove on pulleys and sheaves. V-belt drives can transmit more power for the same dimensions because they have a wider contact surface between the pulley and the belt section (bottom + 2 sides).
The following are some key characteristics of V belts:
- Available in a broad range of sizes, strengths, and materials,
- high power transmission capacity.
- Low cost
- Installation is simple and inexpensive.
- The arrangement is compact.
- Due to the wedging effect with pulleys, flat belts have a lower efficiency than flat belts.
Toothed Belt Drive
Although flat, round, and V belts are excellent at transferring motion, they do have some drawbacks. Belt slip, for example, can not be eliminated in any of them. We must employ toothed belts in instances where there is no room for slippage. A toothed belt is a positive transfer belt that transfers power without friction. It delivers forces through teeth in the same way that chain or gear drives do, but with far less noise and no need for excessive lubrication. As a result, these belts are often referred to as synchronous belts or timing belts. They are often used to power camshafts in vehicles and motorcycle engines.
A link belt is a form of a belt that is made up of several individual links. To adjust the length of the belt, these links can be attached and detached as needed. Polyurethane linkages are commonly used, with a multilayer woven polyester fabric for reinforcement. Link belts are similar to endless belts in that they do not require special pulleys to operate. They have the same power and speed ratings as endless belts of similar size. Because the machine does not need to be disassembled, it is simple and quick to install.
Link belts are more expensive than other options, limiting their use in budget-conscious situations. However, they do have superior vibration dampening properties and are far more resistant to external variables than rubber belts.
Advantages and Disadvantages of Belt Drives
Advantages of Belt Drives
Belt drives offer the following advantages compared with other types of drives:
(i) They can be used for power transmission between the axes of driving and driven shafts having considerable distances between them.
(ii) The belt drive operation is smooth and silent.
(iii) Simple design and low initial cost.
Disadvantages of Belt Drives
(i) Have large dimensions and thus occupy space.
(ii) The velocity ratio is not constant due to belt slip.
(iii) They impose heavy loads on shafts and bearings.
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