Underutväxling

Underutväxling, often seen in the context of mechanical engineering and vehicle transmissions, refers to a gear ratio where the output shaft rotates faster than the input shaft. This is achieved by having a smaller gear driving a larger gear, or by a specific arrangement of gears within a gearbox. The primary effect of underutväxling is an increase in rotational speed at the expense of torque.

In practical applications, underutväxling is commonly found in the highest gears of a vehicle's transmission. For instance, in a car's overdrive gear, the engine might be turning at a relatively high RPM, but the wheels are rotating at a slower rate relative to the engine's speed. This allows for more fuel-efficient cruising at highway speeds, as the engine operates at a lower, less demanding RPM. Conversely, in situations requiring high torque, such as starting from a standstill or climbing a steep incline, a lower gear ratio (overutväxling) is typically employed. The concept is also relevant in other mechanical systems where speed multiplication is desired, though the term "underutväxling" is most frequently associated with automotive transmissions.