Banddrivare

Banddrivare, or belt drive, is a mechanism for transmitting power and motion between rotating shafts using a belt that loops around two or more pulleys. The belt is driven by a driving pulley and transfers torque to a driven pulley through friction, with belt tension maintained by a take-up device or by fixed length. Belt drives are valued for their simplicity, low cost, and ability to absorb shocks.

There are several configurations. An open belt drive places the pulleys in the same plane so the belt runs straight; a crossed belt drive twists the belt between pulleys, reversing rotation and increasing friction. In multi-pulley systems, belts or stepped pulleys provide different speed ratios. Synchronous or timing belts use toothed profiles to prevent slip. Belt materials include flat belts, V-belts, and timing belts made from rubber, polymers and fabric cords.

Key components include the belt, drive and driven pulleys, and tensioning or idler devices. Proper alignment and appropriate belt tension are essential to prevent wear, noise, and slippage. Wear can be accelerated by heat, contamination, or misalignment.

Banddrivare are used where gradual power transmission is sufficient and where a buffer against overload or vibration is beneficial. They remain common in automotive accessory drives (alternator, water pump, air conditioning) and in various machinery and conveyors. In many applications, timing belts are used to maintain a fixed speed ratio and reduce the risk of belt slip, while serpentine or multiple-V-belt layouts provide compact power transmission in engines.