One’s teeth of a helical gear are set at an angle (relative to axis of the gear) and take the form of a helix. This allows the teeth to mesh gradually, starting as point get in touch with and developing into collection get in touch with as engagement progresses. Probably the most noticeable benefits of helical gears over spur gears is usually much less noise, especially at medium- to high-speeds. Also, with helical gears, multiple teeth are often in mesh, this means less load on each individual tooth. This results in a smoother transition of forces in one tooth to another, so that vibrations, shock loads, and wear are reduced.
However the inclined angle of the teeth also causes sliding get in touch with between the teeth, which generates axial forces and heat, decreasing performance. These axial forces perform a significant part in bearing selection for helical gears. Because the bearings have to helical gear china endure both radial and axial forces, helical gears need 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 movement, the helix position is typically limited to 45 degrees because of the production of axial forces.