Several Measures to Improve the Performance of Planetary Reducer
Several Measures to Improve the Performance of Planetary Reducer
Feb 27, 2019

Several ways to improve the performance of reducer from design and manufacture are as follows:

1. reasonable design of gear number and modulus.

The tooth number of the reducer determines the transmission speed reduction ratio, while the tooth number and modulus of the gear determine the load bearing capacity of the reducer. Among all kinds of gears of the reducer, the working condition of the sun wheel is worse, so it is necessary to choose the number of teeth and modulus according to the specific working condition of the reducer, and check the force of the sun wheel first. At the same time, in order to reduce the errors that may occur in the manufacture of gears, when the number of teeth is selected, the transmission ratio is a non-integer of prime numbers. This number of teeth can avoid periodic manufacturing errors of gears, resulting in vibration or abnormal sound.

2. set reasonable tooth side clearance.

The meshing of backlash gears can avoid the interference between teeth caused by manufacturing errors and thermal deformation, and facilitate the storage of lubricating oil. However, excessive clearance can obviously lead to the impact of gear on mesh, and then increase vibration and noise.

3. increase the coincidence degree of gear engagement.

The degree of coincidence of gear engagement represents the mean value of the logarithm of the teeth at the same time. The greater the coincidence degree, the more stable the gear transmission, the smaller the impact of gear engagement, the lower the noise.

4. gear modification

Gear modification includes tooth crown modification and tooth profile modification. The tooth profile of the gear is elastically deformed when it is meshed. When it is cut in or out of meshing, the top and root of the driven gear interfere, and the meshing stiffness changes sharply at the same time, which causes serious excitation. Gear modification can not only avoid interference, reduce excitation and dynamic load, but also reduce the effect of additional dynamic load caused by the pitch error of base circle.

5. gear material and surface treatment

The bearing capacity of the reducer is not only related to the tooth number modulus, but also directly related to the material selection of the gear and planetary frame. Generally, materials such as 40Cr, 42CrMo and 20CrMnTi are used under high speed and heavy load condition. In order to further improve the bearing capacity of gears and planetary frames. After heat treatment, the gear face has a certain thickness of hardening layer, the hardness can reach HRC60, has a high bearing capacity, and the gear heart hardness is low, making the gear has a certain degree of toughness.

6. manufacturing accuracy

The manufacturing accuracy of any machine will directly affect the mechanical properties of the machine, especially the machinery with high precision requirements. The accuracy of planetary gear reducers used for large machinery used in general engineering is above 7 grade.

The accuracy of gear manufacturing is one of the most important aspects of gear surface roughness. Because the gear pair transfers torque by contact and slides between teeth during transmission, the smaller surface roughness can reduce the wear between teeth, reduce the heat of the gear, improve the life of the gear transmission and the bearing capacity of the gear. In order to obtain high surface topography, gear grinding process is needed.

The manufacturing precision of gears also involves the accumulated error of gear pitch, the radial runout deviation of gear ring and the deviation of tooth orientation. These precision indexes are used to measure the deviation between the actual tooth profile and the ideal tooth profile. If the total deviation of the machined tooth profile is large, the force will be uneven, resulting in vibration and noise.

7. reasonable load sharing mechanism

In reality, the manufacturing error of gears always exists, and the load-sharing mechanism used in gear transmission device can automatically compensate various manufacturing and installation errors between gears and planetary frames, so as to achieve load balance. The planetary gear reducer usually adopts the floating load sharing mechanism with basic frame, which is divided into single component floating and two components floating simultaneously. A single component floats with a sun wheel, an internal gear and a planetary frame. The two components float with a sun wheel and an internal gear simultaneously, and the sun wheel and the planetary frame float. The floating effect of two components is better than that of a single component.

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