variaattorit

Variaattorit, also known as variable pitch pulleys or continuously variable transmissions (CVTs) in some contexts, are mechanical devices used to change the speed ratio between two rotating shafts. They typically consist of two pulleys, each with adjustable sheave halves. The effective diameter of each pulley can be changed by moving the sheave halves closer together or further apart.

When the sheaves on one pulley move closer, its diameter increases, and conversely, when they move apart, its diameter decreases. This change in diameter is synchronized with the opposing pulley. For example, if one pulley's diameter increases, the other's must decrease to maintain tension in the belt or chain connecting them. This continuous adjustment allows for an infinite number of speed ratios within a certain range, unlike traditional gearboxes that offer a fixed number of discrete ratios.

Variaattorit are commonly found in applications where smooth and stepless speed adjustment is desirable. This includes snowmobiles, scooters, ATVs, and some agricultural machinery. Their ability to keep an engine operating at its most efficient speed, regardless of vehicle speed, contributes to fuel economy and improved performance. The mechanism relies on a belt or chain running between the two variable-diameter pulleys. The tension in the belt is crucial for proper operation and is often maintained by a spring-loaded system or hydraulic pressure.