Helical gear, also known as helical cylindrical gear, is a common type of gear transmission device. Unlike spur gears, the teeth of helical gears are in the form of slanted lines rather than straight lines. Helical gears are typically used in non-parallel axis transmission systems, enabling rotational transfer between two shafts and solving situations where parallel axis transmission is not suitable.

The teeth slots of Helical gears are inclined at a certain angle to the gear axis, known as the pressure angle. The choice of pressure angle affects the transmission performance and efficiency of Helical gears. The number of teeth and module of helical gears are essential parameters used to describe the gear size, similar to spur gears.

Key features of helical gears include:

Parallel Axis Transmission: Helical gears can transmit rotational motion between parallel axes, allowing both shafts to rotate simultaneously.

High Transmission Efficiency: Due to the slanted tooth profile, helical gears enable smoother meshing during transmission, resulting in improved transmission efficiency.

Strong Load-Carrying Capacity: The wider tooth slots of helical gears give them a strong load-carrying capacity, suitable for transmitting higher torque.

Smooth Transmission: The inclined tooth slots of helical gears ensure a more stable transmission, with relatively low noise.