Compared with the helical gear reducer, the disadvantage of the spur gear reducer is that it will generate vibration.Whether due to design, manufacturing, or deformation, some variation in the involute shape may occur simultaneously along the entire tooth flank.This causes each tooth to touch once, usually very firmly.The resulting vibrations not only place high loads on the gears, but also generate noise.
Another disadvantage of spur gear reducers is that it is sometimes impossible to take advantage of the additional strength gained by meshing when two pairs of teeth are in contact, because the stresses generated by the meshing of a single tooth in a cycle are limited.
Then the helical gear reducer is different.Its helical gear can be regarded as a cylindrical gear formed by a set of thin plate gears misaligned.In this way, the contact of each plate is at a different part of the tooth profile, thereby compensating for the error of each thin plate gear.This compensating effect is very effective for the elasticity of the teeth and is also beneficial for the load-bearing strength.
Furthermore, it is complex, difficult and uneconomical to manufacture and assemble large numbers of thin spur gears.Therefore, manufacturers make connecting gears that have teeth in the helical direction.Although helical gears are not like spur gears, they generate very little axial force.However, the advantages of reducing vibration and improving bearing strength are far better than the disadvantages of slightly increasing axial thrust and manufacturing cost.Therefore, in the manufacture of gear reducers, helical gears are often used instead of spur gears.
