The teeth of a helical gear are set at an angle (in accordance with axis of the gear) and take the form of a helix. This allows one’s teeth to mesh steadily, starting as point get in touch with and developing into line get in touch with as engagement progresses. One of the most noticeable advantages of helical gears over spur gears is less noise, especially at medium- to high-speeds. Also, with helical gears, multiple tooth are generally in mesh, this means less load on each individual tooth. This results in a smoother changeover of forces in one tooth to the next, so that planetary gearbox vibrations, shock loads, and wear are reduced.

However the inclined angle of the teeth also causes sliding contact between your teeth, which generates axial forces and heat, decreasing performance. These axial forces enjoy a significant function in bearing selection for helical gears. As the bearings have to endure both radial and axial forces, helical gears need thrust or roller bearings, which are usually larger (and more costly) than 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 larger helix angles offer higher quickness and smoother movement, the helix angle is typically limited by 45 degrees due to the production of axial forces.