Drive belts operate the accessories of a vehicle by riding along a track of pulleys. The belts are driven directly by the engine's crankshaft. Drive belts operate the water pump, alternator, power-steering pump and air-conditioner compressor. An idler may also be present to aid belt tension.
The drive belt dates back to the industrial revolution. When front-wheel drive was not the norm, drive belts were sometimes referred to as fan belts because they also drove the engine's cooling fan along with the engine accessories.
The drive belt is inexpensive and does not require alignment or shafts. They protect against jams or overload. The belts also isolate against noise and vibration. Load fluctuations are cushioned. No lubrication and minimum maintenance is required. Efficiency rates are 90 to 98 percent.
The Vee Belt (or V belts) are the basic belt for power transfer. They provide the best speed, traction, bearing load and a long life. The V belt was developed in 1917 by John Gates of the Gates Rubber Co. These types of belts got their name from the v-shaped cross section. They were once the most common type of belt used in automobiles.
A development in drive-belt technology emerged in the 1980s. The newer belt has longitudinal grooves fit into a grooved surface of a special pulley. Serpentine belts drive all accessories of the engine because both sides of the belt drives the pulleys. Power transfer is better as compared to the V belt.
The timing belt is a cogged belt and is used in lieu of gears or chains in many overhead-cam four-cylinder engines. The belt has teeth that fit into a matching tooth pulley. They are less noisy than chains. The belts are used for direct motion for indexing or timing purposes, hence the name.
