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An annulus, in mechanical engineering and gear terminology, refers to a type of gear that is ring-shaped and features teeth on its inner circumference rather than the outer circumference. Here are the key characteristics of an annulus:

  1. Shape: An annulus is a circular gear that resembles a ring. It has a hollow center and teeth cut along the inside diameter of the ring.
  2. Function: An annulus is designed to mesh with an external pinion gear whose teeth engage with the internal teeth of the annulus. This gearing arrangement allows for the transfer of rotational motion and torque.
  3. Applications: Annuli are commonly used in various mechanical systems where space constraints or specific design requirements necessitate a ring-shaped gear with internal teeth. They can be found in applications such as planetary gear systems, where they serve to transmit motion and power within a compact assembly.
  4. Design Considerations: The design of an annulus ensures that the teeth are properly aligned and engage smoothly with the pinion gear, providing efficient power transmission and reducing wear on the gear teeth.

Annuli are critical components in gearboxes, transmissions, and other machinery where rotational motion needs to be transmitted with precision and efficiency. Their design allows for effective torque transfer while optimizing space utilization in mechanical systems.

See Related Term:

  • Epicyclic gearbox
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