What is the helix direction of gear teeth?
Some types of gears have twisted teeth, such as helical gears, and others have curved teeth, such as spiral bevel gears.
The helix direction of gear teeth means the direction in which the teeth of those gears are inclined, and is expressed as Right or Left.
In the case of a pair of helical gears that mesh with each other, the helix directions of the teeth of both gears are opposite (Right and Left). In the case of a helical rack and helical gear combination or spiral bevel gears, the helix directions of their teeth are also opposite.
On the other hand, in the case of screw gears used on nonparallel and nonintersecting axis and worm gears (a combination of worm and worm gear), the helix direction of a pair of gear teeth is the same (Right and Right or Left and Left).
