V-belts

V-belts are flexible drive belts with a distinctive trapezoidal (V-shaped) cross-section used to transmit power and torque between grooved pulleys (sheaves). Their unique shape causes them to wedge into the pulley grooves as tension increases, significantly enhancing grip, reducing slippage, and enabling efficient power transmission in a wide range of applications.

Design and Function
The function of a V-belt drive is based on friction and the wedging action within the pulley groove.
Wedging Action: The V-shape increases the effective friction between the belt and the pulley sidewalls, which means less tension is required to transmit the same amount of torque compared to flat belts.
Power Transmission: The belt is typically made of a flexible rubber compound and reinforced with high-strength tension members, or "cords," embedded within the rubber to provide the necessary strength and resistance to stretch.
Shock Absorption: The base rubber compound acts as a shock absorber during operations, which helps dampen vibrations and contributes to smoother, quieter system operation.
Protective Covering: A textile or plastic cover often wraps the belt, protecting the internal components from friction damage, oil, heat, and external contaminants.
Types of V-Belts
V-belts come in various types and standard sizes to meet specific application requirements.
Classical V-belts (A, B, C, D, E, Z): The oldest and most common type, capable of handling loads up to 500 horsepower in rough operating conditions, widely used in HVAC systems and industrial machinery.
Narrow V-belts (3V, 5V, 8V): Feature steeper angled sidewalls for enhanced wedging and load capacity, ideal for transmitting large loads in a compact space.
Raw Edge and Cogged Belts: These belts have raw, uncovered flanks or cogs (notches) on the underside to provide greater flexibility, allow for smaller pulley use, and improve efficiency by eliminating slippage.
Banded Belts: Consist of multiple V-belts joined by a common top band, used to prevent individual belts from turning over or jumping off the pulley grooves in vibrating or pulsating drives.
Poly-V Belts (Serpentine Belts): Combine the high flexibility of a flat belt with the grip of V-belts, featuring multiple longitudinal ribs. They are used for complex serpentine drives and transmit power by contact of the belt rib flanks.
Common Applications
Due to their versatility and reliability, V-belts are used in numerous applications.
Automotive Engines: Driving accessories such as the alternator, air conditioning compressor, power steering pump, and cooling fan.
Industrial Machinery: Powering components in air compressors, pumps, metalworking machinery, and material conveyors.
Agricultural Equipment: Utilized in various farm machines for power transmission under tough environmental conditions.
Consumer Goods: Found in vacuum cleaners, lawn mowers, washing machines, and treadmills.