kehäpyöräksi

Kehäpyörä, often translated as "ring gear" or "annular gear" in English, is a type of gear with teeth on the inner surface of a ring or cylinder. Unlike conventional gears that have teeth on the outer circumference, the teeth of a kehäpyörä face inwards. This unique design allows it to mesh with an external gear, known as a aurinkopyörä (sun gear), and often one or more planetaaripyörä (planet gears) to form a planetary gear system.

The primary function of a kehäpyörä in a planetary gear set is to provide the outer boundary of the system and dictate the output speed and torque in conjunction with the sun and planet gears. As the planet gears rotate, they roll along the inner teeth of the kehäpyörä, causing the central sun gear and the entire assembly to rotate. The ratio of the number of teeth on the kehäpyörä to the number of teeth on the sun gear determines the overall gear ratio of the system.

Kehäpyörä are commonly found in applications requiring high torque density and compact design, such as automatic transmissions in vehicles, industrial gearboxes, and wind turbines. Their ability to achieve significant gear reduction within a small space makes them highly versatile. The meshing of the planet gears with the internal teeth of the kehäpyörä also contributes to the smooth and balanced operation of planetary gear systems. The manufacturing of kehäpyörä typically involves precision machining to ensure proper meshing and durability.