The teeth of a helical gear are set at an angle (in accordance with axis of the apparatus) and take the form of a helix. This allows the teeth to mesh steadily, gear rack starting as point get in touch with and developing into collection get in touch with as engagement progresses. One of 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 constantly in mesh, this means less load on each individual tooth. This results in a smoother changeover of forces from one tooth to the next, so that vibrations, shock loads, and wear are reduced.

However the inclined angle of one’s teeth also causes sliding contact between your teeth, which produces axial forces and heat, decreasing efficiency. These axial forces enjoy a significant part in bearing selection for helical gears. Because the bearings have to endure both radial and axial forces, helical gears require thrust or roller bearings, which are typically larger (and more costly) compared to the simple bearings used with spur gears. The axial forces vary compared to the magnitude of the tangent of the helix angle. Although larger helix angles provide higher acceleration and smoother motion, the helix angle is typically limited by 45 degrees due to the creation of axial forces.