A pulley is a wheel that has a groove or rim along its outer edge. It is a movable part of the belt drive or wireline and serves to transfer the rotational movement of some parts or mechanisms to others. Pulleys are sometimes used on camshafts in mechanical blocks. But the pulley, unlike the block, which itself rotates on the axis and serves only to change the direction of movement of the belt or rope, is stationary and transfers movement from the belt or rope to the axis.
A rather large percentage of drives of modern technology belongs to belt drives with pulleys (fixedly fixed two pulleys with a belt stretched over them). It is easy to understand, knowing about their merits:
• V-belt transmissions are capable of transmitting huge power flows (up to 400,000 W of energy), jagged and poly-V-belt drives, and even more (up to 500,000 W-toothed and up to 1,000,000 W-poly-wedge); wedge and poly-clay transmissions can operate at high speeds (30-50 m / s – wedge and 100 m / s – poly-wedge);
• belt drives with pulleys ensure the transmission of rotational motion over long distances to parts with any location in space, even vertical;
• smooth running,
• practically no noise during operation,
• Low level of vibrations and loads on parts of equipment, as a result of the increase in the service life
• A fairly simple design.
Depending on the shape of the groove (grooves), the pulleys are divided into several types:
– pulleys for flat belts (their working surface has a small bulge in order to prevent the belts from falling off). They protect aggregate assemblies from breakage, reducing vibration;
– pulleys for V-belts (their grooves have the form of a trapezoid). Wedge-shaped pulleys are used much more often than others. They consist of the main and secondary pulleys and wedge-shaped belts connecting them;
– pulleys for belts with a circular cross-section (at their recesses rounded bottom);
– pulleys for toothed belts (they have special teeth directed along the axis). Such pulleys are used for high power. Their main drawback is that they are not very durable;
– pulleys with multiwheel belts. By crochet pulleys belts, often, apply standard. They can have up to 10 streams. They are used at high loads;
– brake pulleys. They look like a wheel with a wide rim, they are used in the production of all crane mechanisms. They are used to stop and fix shafts with the motor disconnected. Such pulleys are more thoroughly tested for all indicators.
Also, pulleys are welded and all-metal. Welded pulleys are used only at small speeds of equipment operation (no more than 30 m / s). If the speed of operation is higher, then there is a risk of rupture of the pulley, in such cases it is better to use an all-metal pulley.
Among the materials from which pulleys are made, cast iron, steel, aluminum, caprolin, textolite and fluoroplastic are very popular. The choice of material for the pulley depends on the further use of the pulley.
All kinds of pulleys are produced by turning metalwork. This is an extremely complex and time-consuming process that requires special precision in the grinding and balancing of the product. PP Yagotinsky Mechanical Plant is ready to take orders for the manufacture of pulleys and other metal products of any complexity.