The motion law of gears when the center hole of the gear is eccentric

When the center hole of the gear is eccentric, its motion pattern will be significantly affected, mainly reflected in the following aspects:

1、 Increased transmission error

Change in meshing angle: Gear eccentricity can cause a change in the angle of gear meshing, which directly affects the accuracy of transmission. Due to the deviation of meshing angle, gears will generate additional transmission errors during the transmission process.

Increased backlash: Eccentricity can also increase the backlash of gears, that is, the clearance between teeth will increase during the meshing process. Excessive backlash can lead to increased impact and vibration between gears, further affecting the smoothness of transmission.

2、 Increased vibration and noise

Dynamic load variation: Gear eccentricity can cause changes in the dynamic load of the transmission system, resulting in uneven load distribution. This uneven load distribution can cause system vibration, and an increase in vibration amplitude and frequency will further exacerbate the generation of noise.

Mesh stiffness variation: In the process of gear transmission, mesh stiffness is an important parameter. When the gear is eccentric, the meshing stiffness will change, especially when the gear enters the double meshing zone from the single meshing zone, the sharp change in meshing stiffness will lead to increased vibration.

3、 Wear and tear and increased energy consumption

Increased wear: Due to transmission errors, vibrations, and impacts caused by eccentricity, gear wear will intensify. Wear not only affects the transmission accuracy and lifespan of gears, but also increases the maintenance cost of the system.

Increased energy consumption: Transmission errors and vibrations caused by eccentricity can lead to a decrease in transmission efficiency, thereby increasing the energy consumption of the system. In addition, in order to overcome the additional resistance and vibration caused by eccentricity, the transmission system needs to consume more energy.

4、 Specific phenomena

Time domain waveform variation: In the time domain waveform, the phenomenon of gear eccentricity is manifested as the appearance of speed modulation components, that is, the waveform amplitude fluctuates up and down with the gear rotation frequency period.

Spectral characteristics: In spectral analysis, the characteristic of gear eccentricity is manifested as an increase in the meshing frequency and its harmonic amplitude of the gear, especially in the 1st and 3rd harmonics. At the same time, multiple sidebands modulated by gear rotation frequency will appear on both sides of the gear meshing frequency and its harmonics.