Drive Belts & V Belts

A drive belt is a length of synthetic flexible material or rubber, joined to make a loop. Drive belts or V belts are used to join two or more pulleys together. The belts are designed to be fitted to the outer edge of the pulley. When tension is applied to the belt it creates friction, thus transferring friction into motion. How to identify the correct belt Identifying the correct size belt for your application is critical. As belts can stretch over time is it all too easy to make a mistake. One way to ensure you make the correct selection is by checking to see if the drive belt still has any manufacturers part numbers printed on the belt. If this is not possible due to wear then you need to measure the belt in two very specific ways. A drive belts size is determined by two things, the length and the width. Measuring the length The length of the drive or V belt is calculated by measuring the inner circumference of the belt. This can be done with either a specialist V belt measuring tool or a cloth tape. Do not try to measure with a steel tape or ruler. Once you have the circumference of the belt make the tape straight giving you the length. Measuring the width If you look at a belts cross section a V or wedge belt will have trapezoidal shaped teeth along the inner side of the belt. To measure the width simply measure across the top of the Vee and the height of the vee. The two measurements relate to ‘section’ size. Belt Types Once you have the two measurements the figures can be used to identify the belt ‘type’. The width measurement would generally appear as a single letter or three letters x the length. Typical belts would appear like, A Section x Length B Section x Length Z Section x Length XPZ Section x Length SPZ Section x Length SPB Section x Length Applications and uses Drive belts, V belts and wedge belts are used in a wide range of industrial power transmission applications that utilise pulleys, tensioners, sprockets and gears. Some of the most common are • Conveyor rollers • Generators • Air conditioning compressors • Water pumps • Alternators • Power steering pumps • Automotive engines • Lawn mowers