Why are helical gears used in the manufacture of reducers?

The main disadvantage of spur gears is that they generate vibrations.Some variation in the involute profile may occur along the entire flank at the same time, whether due to design, manufacturing or deformation reasons.This will result in a regular, once per tooth excitation, which is often very strong.The resulting vibrations cause both large loads on the gears and noise.A further disadvantage is that the additional strength sometimes obtained by the meshing of two pairs of teeth during the contact time cannot be utilized because the stress is limited by the condition of the meshing of the single teeth during the cycle.

  The helical gear can be regarded as a cylindrical gear formed by dislocation of a group of thin-toothed gears, so that the contact of each piece is at different parts of the tooth profile, thus compensating for the error of each thin-film gear. The elasticity of the teeth is very effective, which leads to the result that teeth within 10mm of error can average the error and thus run as smoothly under load as teeth within 1mm of error.

  Since at any instant there will be two teeth meshing about half the time (assuming a coincidence of about 1.5) this provides an additional benefit in terms of strength.Therefore the stress can be based on 1.5 times the tooth width instead of one tooth width.

  It is difficult and uneconomical to manufacture and assemble a large number of lamellar spur gears, so one-piece gears with teeth in the helical direction are manufactured.Unlike spur gears, helical gears can cause undesirable axial forces.But the benefits in terms of vibration and strength far outweigh the disadvantages caused by axial thrust and slightly increased manufacturing costs.Therefore, helical gears are used instead of spur gears in the manufacture of reducers. For example, four series: R series coaxial helical gear reducers, K series spiral bevel gear reducers, S series helical worm gear reducers, F series parallel shafts Helical gear reducer. Note 1: What is a spur gear: A spur gear is a gear whose teeth are parallel to the axis of rotation.We only discuss the theory of parallel shaft gear transmission, so any cross section perpendicular to the two gear shafts is exactly the same.