The teeth of a helical gear are set at an angle (in accordance with axis of the gear) and take the shape of a helix. This enables the teeth to mesh steadily, starting as point get in touch with and developing into range get in touch with as engagement helical gear china progresses. One of the most noticeable benefits of helical gears over spur gears is definitely much less noise, especially at moderate- to high-speeds. Also, with helical gears, multiple teeth are at all times in mesh, which means much less load on each individual tooth. This 
outcomes in a smoother changeover of forces from one tooth to another, so that vibrations, shock loads, and wear are reduced.
But the inclined angle of the teeth also causes sliding contact between the teeth, which produces axial forces and heat, decreasing performance. These axial forces play a significant function 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 expensive) than the simple bearings used in combination with spur gears. The axial forces vary in proportion to the magnitude of the tangent of the helix angle. Although bigger helix angles offer higher rate and smoother motion, the helix position is typically limited to 45 degrees due to the creation of axial forces.