Sisähammaspyörät

Sisähammaspyörät, also known as internal gears, are gears where the teeth are cut on the inside surface of a ring or cylinder. This is in contrast to external gears, where the teeth are on the outside. The teeth of an internal gear mesh with the teeth of an external gear. When meshed, the internal gear rotates in the same direction as the external gear. This is a key difference from external gear pairs, which rotate in opposite directions.

Internal gears are often used in applications where a compact design is desired, or where a high gear reduction is needed. They can be found in planetary gear systems, where a sun gear meshes with one or more internal gears (often called ring gears). They are also utilized in certain types of transmissions and some specialized machinery. The internal gearing design can offer advantages in terms of load distribution and torque capacity compared to some external gear configurations of similar size. The manufacturing process for internal gears can be more complex than for external gears, often requiring specialized tooling like hobbing or broaching.