Causes of Electric Motor Bearing Race

Most motors use rolling bearings. The friction between the bearing rolling element and the inner&outer rings is rolling friction, and the friction between the two contact surfaces is very small. The fit between bearing and shaft, bearing and end cover is generally interference fit, and a few cases are transition fit. The mutual extrusion force is relatively large, resulting in static friction. The bearing and shaft, bearing and end cover remain relatively stationary, and the mechanical energy is transmitted by the rotation between the rolling element and the inner ring (or outer ring).

Bearing Race

If the fit between the bearing and the shaft and the bearing chamber is clearance fit, the torque will destroy the relative static state and produce sliding, resulting in the so-called "race", the sliding between the bearing inner ring and the shaft is called race inner ring, and the sliding between the bearing outer ring and the bearing chamber is called race outer ring.

Appearance and Harm of Bearing Race

If the bearing race occurs, the temperature of the bearing will be too high and the vibration will be large. During disassembly and inspection, it will be found that there are slip marks on the surface of the shaft (bearing chamber), and even grooves are worn on the surface of the shaft or bearing chamber. From this situation, it can be concluded that the bearing race.

The running outer ring of bearing has a great negative impact on the equipment, which will aggravate the wear of mating parts, even scrap, and even affect the accuracy of supporting equipment; In addition, due to increased friction, a large amount of energy will be converted into heat and noise, which greatly reduces the efficiency of the motor.

Causes of Bearing Race

(1) Fit Tolerance: there are strict requirements for the fit tolerance between bearing and shaft. Different specifications, accuracy, stress conditions and operating conditions have different requirements for fit tolerance.

(2) Machining and Installation Accuracy: refers to the machining tolerance, surface roughness, assembly accuracy and other technical parameters of shaft, bearing and bearing chamber. Once the requirements are not met, the fit tolerance will be affected, resulting in bearing race.

(3) Material of Shaft and Bearing. Different types of bearings should be made of appropriate bearing steel, with high strength and stiffness, good wear resistance and small friction coefficient of bearing alloy, to ensure the normal use of bearings and reduce the possibility of race.

Common repair measures for bearing race: bushing, pitting, surfacing, brush plating, thermal spraying, laser cladding and so on.

Surfacing: surfacing is the welding process of depositing a layer of wear-resistant, corrosion-resistant and heat-resistant metal layer on the surface or edge of the work piece.

Thermal Spraying: thermal spraying is a metal surface processing method that atomizes and sprays the molten spraying material on the surface of parts through high-speed air flow to form a spraying layer.

Brush Plating: brush plating is the process of obtaining the coating on the workpiece surface by electrolytic method.

Laser Cladding: laser cladding is a new surface modification technology.