Basic characteristics of planetary gear mechanism

Through the analysis of the above three kinds of transmission relations, the kinematic characteristics of simple planetary gear mechanism can be summarized as follows:

1.When the planet carrier is the driving part, the driven part is overspeed.

2.When the planet carrier is a follower, the speed of the planet carrier must be lower than that of the driving part.

3.When the planet carrier is fixed, the driving part and the driven part rotate in the opposite direction.

4.When the sun wheel is the driving part, the speed of the driven part will decrease.

5.If the planet carrier is a passive part, its rotation direction is the same as that of the active part.

6.If the planet carrier is the active part, the rotation direction of the passive part is the same as that of the active part.

7.In the simple planetary gear mechanism, the number of sun gear teeth is the least, the equivalent number of planet carrier teeth is the most, and the number of ring gear teeth is in the middle. (Note: the equivalent number of teeth of planet carrier = dozens of ring gear teeth of sun gear.)

8.If any two components of the planetary gear mechanism rotate at the same speed and in the same direction, the speed and direction of the third component must be the same as the first two components, that is, the mechanism is locked and becomes a direct gear. (this is a very important feature, although the above examples do not cover it.)

9.When there is only one driving part and two other parts are not fixed, it is in neutral.

The kinematic relationship of simple planetary gear mechanism is often encountered. When determining the relationship among the three, first fix one of them, and then determine the active and passive relationship between the other two. In fact, the simple planetary gear mechanism also has a very important feature, allowing two pieces to be input at the same time as the active part, while the passive part still has a unique output, which is a very important feature of the planetary gear mechanism, and widely used in automatic transmission.

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