Both spur gear planetary reducers and helical gear planetary reducers belong to the category of precision planetary reducers, but among them, helical gear planetary reducers belong to high-precision planetary reducers. So some people who are not very familiar with planetary reducers are very puzzled. One is a straight tooth, and the other is a helical tooth, but it's just this difference. Why is one a precision planetary reducer and the other a high-precision planetary reducer? In fact, the difference between a spur gear planetary reducer and a helical gear planetary reducer is not just that. There are still many differences between them. Now let's take a look at the differences between a spur gear planetary reducer and a helical gear planetary reducer.
The main drawback of spur gears in planetary reducers is that they generate vibration. Regardless of design, manufacturing, or deformation reasons, some changes in the involute shape may occur along the entire tooth surface at the same time. This will lead to a regular, tooth to tooth excitation, which is often very strong.
The resulting vibration not only causes a large load on the gear, but also generates noise. Another disadvantage is that sometimes the additional strength obtained from the meshing of two pairs of teeth during contact time cannot be utilized, as the stress is limited by the condition of single tooth meshing in the cycle.
The helical gear used in the helical gear reducer can be seen as a cylindrical gear composed of a group of thin toothed gears that are misaligned. In this way, the contact of each plate is at different parts of the tooth profile, thereby generating a compensation effect for the error of each thin toothed gear. This compensation effect is very effective due to the elasticity of the teeth, and thus the result is that teeth with an error of less than 10mm can make the error average. Therefore, under load conditions, Can run smoothly like teeth with an error of within 1mm.
Because at any moment, approximately half of the time (assuming a coincidence of approximately 1.5) there will be two teeth meshing, which brings additional benefits in terms of strength. Therefore, stress can be established on the basis of 1.5 times the tooth width, rather than just one tooth width.
Manufacturing and assembling a large number of thin spur gears is both difficult and uneconomical, so it is necessary to manufacture gears that are connected as a whole and have teeth in the direction of the helix. Unlike spur gears, helical gears can cause poor axial force. But the benefits in terms of vibration and strength far outweigh the drawbacks caused by axial thrust and slightly increased manufacturing costs.
Straight tooth planetary reducer and helical tooth planetary reducer can be said to have their own advantages and disadvantages. The manufacturing cost of helical planetary reducers is higher than that of spur planetary reducers. However, helical gear planetary reducers have significant advantages in vibration and strength.
