Advantages and disadvantages of the spur gear and helical gear

Large range of transmission ratio, high efficiency, and easy processing.

Disadvantages as below:
1. The main reason is that they generate vibration;
2. Whether it is due to design, manufacturing, or deformation, some changes in the involute shape may occur along the entire tooth surface at the same time;
3. This will result in a regular, one-to-one excitation, which is often very strong. The resulting vibrations cause both large loads and noise on the gears;
4. Also, the additional strength sometimes obtained by the meshing of two pairs of teeth during the contact time cannot be used because the stress is limited by the condition of the single meshing in the cycle;
5. It can only bear radial load and not axial load, which causes unreasonable load distribution and shortens the overall life of the gearbox.

Advantages:
The helical gear used in the helical gear reducer can be regarded as cylindrical gear made of a group of thin toothed gears. In this way, the contact of each piece is at a different part of the tooth profile, thereby compensating for the error of each thin gear. This compensation effect is very effective due to the elasticity of the gear teeth. Therefore, this result is obtained. Gear teeth with an error within 10mm can make the error average, so under load, it can be used for wheels with an error within 1mm. The tooth runs smoothly. Because at any instant, about half the time (assuming a coincidence of about 1.5), two teeth will mesh, which brings additional benefits in terms of strength. Therefore, the stress can be based on 1.5 times the tooth width instead of a tooth width.

Disadvantages:
1. Causes bad axial force;
2. Slightly increased manufacturing costs.

Overview of spur and helical gears
1. It is difficult and uneconomical to manufacture and assemble a large number of thin spur gears. Therefore, it is manufactured into gear with the teeth along the spiral direction.
2. A helical gear is not like spur gear, it will cause bad axial force. 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.

 

Please SDT Transmission Team if you have any queries.