Which gear type is known for its smooth operation compared to spur gears?

Helical gears are known for their smooth operation because of the way their teeth are angled relative to the axis of rotation. Unlike spur gears, which have teeth that are parallel to the gear's axis, helical gears feature teeth that are set at an angle (helical) to the axis. This design allows for multiple teeth to engage at once during operation, which leads to a more gradual and smooth engagement. The inclined angle reduces the impact during the meshing process and helps to distribute the load evenly, resulting in quieter and more efficient performance.

In contrast, spur gears can generate more noise and vibrations during operation due to their direct engagement, where the teeth contact all at once. Other gear types, while they may offer unique advantages, do not necessarily match the smooth operation characteristic of helical gears in terms of noise and load distribution.