One’s teeth of a planetary gearbox helical gear are set at an angle (relative to axis of the gear) and take the shape of a helix. This allows one’s teeth to mesh steadily, starting as point get in touch with and developing into series contact as engagement progresses. Probably the most noticeable advantages of helical gears over spur gears can be less noise, especially at moderate- to high-speeds. Also, with helical gears, multiple tooth are at all times in mesh, this means much less load on every individual tooth. This results in a smoother changeover of forces from one tooth to the next, to ensure that vibrations, shock loads, and wear are reduced.

However the inclined angle of the teeth also causes sliding get in touch with between your teeth, which produces axial forces and heat, decreasing effectiveness. These axial forces enjoy a significant role in bearing selection for helical gears. As the bearings have to endure both radial and axial forces, helical gears require thrust or roller bearings, which are typically larger (and more expensive) compared to the simple bearings used in combination with spur gears. The axial forces vary compared to the magnitude of the tangent of the helix angle. Although bigger helix angles offer higher velocity and smoother movement, the helix position is typically limited by 45 degrees due to the production of axial forces.