The vibration and noise generated by the mechanical bearings of the motor are generally caused by the unbalance of the rotor. 3.2 The vibration of the bearing resonates with the motor, or poor lubrication produces frictional noise. 3.3 The brush slides, causing vibration and noise of the motor. 3.4 The fluid vibration noise of the motor, the fan or the rotor caused the ventilation motor vibration noise is difficult to avoid for the motor. In many cases, the overall motor vibration and noise of the motor, in addition to the air whistle sound caused by the fan blades or iron core teeth, also pay attention to the ventilation. Vibes. The electromagnetic vibration noise of the motor is the motor vibration noise caused by the unbalanced magnetic circuit or the unbalanced magnetic force and the electromagnetic force wave of the air gap, or the magnetic motor vibration noise caused by the saturation of the magnetic flux density or the eccentricity of the air gap. Abnormal bearing produces motor vibration and motor vibration noise. Countermeasures: · Replace the bearing. ·Appropriately preload the spring in the axial direction to avoid the change of the axial clearance of the bearing. Choose soft grease or grease with excellent low temperature properties, and the remaining gap should be small (but pay attention to the temperature rise). The main parameter table of each structure type bearing used in the motor Reason: There may be damage inside the bearing. ·The axial abnormality of the bearing causes the motor to vibrate, and the axial spring constant and the rotor mass form the excitation effect of the motor vibration system. ·Friction noise: Cylindrical rolling bearings or large-diameter high-speed ball bearings are caused by poor lubrication and bearing clearance.