On the one hand, the function of the bearing of the high-power reducer is to keep the gear lubricating oil inside the bearing from losing in use, so as to ensure that the bearing is in a lubricating state; on the other hand, it is to protect the dust or harmful gas outside the bearing from entering the bearing cavity, so as to prevent damage to the bearing. The bearing can support the gear shaft or connecting rod between rotations in high-power reducer. Therefore, we discussed the bearing fault diagnosis method of the reducer.
1. Shaft unbalance
Unbalance is the most common fault of high-power reducer. The causes of rotor imbalance include unreasonable structure design, manufacturing and installation errors, uneven materials, corrosion, wear, scaling of rotor in operation, looseness and falling off of parts, etc. Main fault characteristics of shafting imbalance: (1) peak value of shaft frequency or fundamental frequency occurs, and amplitude of other frequency multiplication is small; (2) Large radial vibration; (3) The axis track becomes an ellipse; (4) The intensity of vibration is very sensitive to the change of working speed.
2. Axis misalignment
Shaft misalignment usually refers to the inclination or offset degree between the shaft centerline of two adjacent rotors and the bearing centerline. Shaft misalignment can be divided into coupling misalignment and bearing misalignment, and coupling misalignment can be divided into three situations: parallel misalignment, deflection angle misalignment and parallel deflection angle misalignment. Main fault characteristics of shaft misalignment: (1) The first and second harmonic peaks of the shaft appear in the radial direction of the parallel misalignment, especially the second harmonic. (2) The deflection angle is misaligned, the axial vibration is large, and there are stable peaks at the fundamental frequency, double frequency and even triple frequency. (3) Both axial and radial vibrations occur when the parallel deflection angle is misaligned.