During the operation of the mechanism, the location where railway bearings are installed is allowed to have a certain temperature. When touching the outer shell of the mechanism with hands, it should be normal not to feel hot, otherwise it indicates that the bearing temperature is too high.

The reasons for high bearing temperature include: the quality of lubricating oil does not meet the requirements or deteriorates, and the viscosity of lubricating oil is too high; Tight assembly of the mechanism (insufficient clearance); The bearing assembly is too tight; The bearing race rotates on the shaft or inside the housing; Excessive load; INA bearing cage or rolling element breakage, etc.

Rolling bearings allow for slight operating noise during operation. If the noise is too loud or there is abnormal noise or impact, it indicates that the bearing is faulty.

The reasons for the noise generated by rolling bearings are quite complex, one of which is the wear of the mating surfaces of the inner and outer rings of the bearings. Due to this wear, the fit between the bearings and the housing, as well as between the railway bearings and the shaft, is disrupted, resulting in the axis deviating from its correct position and producing abnormal noises during high-speed movement of the shaft. When the bearing is fatigued, the surface metal peels off, which can also increase the radial clearance of INA bearings and produce abnormal noise. In addition, insufficient lubrication of bearings, dry friction, and bearing breakage can all produce abnormal noises. After bearing wear and looseness, the cage becomes loose and damaged, which can also produce abnormal noises.

1. Key points for bearing maintenance and repair

Maintenance and repair

In order to maintain the original condition of the bearings in good condition for as long as possible, maintenance and repair are necessary to prevent accidents in advance, ensure the reliability of operation, and improve productivity and economy.

It is best to maintain the corresponding operating conditions of the machinery according to the operating standards and conduct regular maintenance. The content includes monitoring the operation status, supplementing or replacing lubricants, and conducting regular disassembly inspections.

(1) Maintenance of INA bearings under operating conditions for rotational sound, vibration, and temperature, as well as maintenance of lubricant properties, and determination of lubricant supplementation or replacement periods.

(2) During regular maintenance and replacement of machinery, the maintenance of bearings involves observing the removed railway bearings thoroughly, checking the condition and damage of the track surface, and confirming whether they can be reused.

2. Maintenance during operation

The maintenance items during operation include the rotational sound, vibration, temperature, and lubricant condition of the bearings.

(1) The rotational sound of bearings

Use stethoscopes and other devices to investigate the level and quality of noise.

Even if a few railway bearings experience abnormal and irregular sounds during fatigue peeling, it is still possible for them to be heard if they are proficient.

Representative abnormal sounds are shown on the following page

(2) Vibration of bearings

Using a bearing vibrator, quantitatively measure and analyze the amplitude and frequency of vibration, and infer the damage condition of the bearing based on this.

However, due to the different usage conditions and measurement positions of INA bearings, it is necessary to use mechanical measurement values to determine the judgment criteria.

(3) Temperature of bearings

The bearing temperature usually rises slowly after the start of operation and reaches saturation after a period of time. The constant temperature of railway bearings varies due to mechanical heat capacity, heat release, speed, and load.

When the bearing temperature rises abnormally before reaching saturation, consider the reasons shown on the following page, stop running and take necessary measures.

(4) Lubrication

Investigating the use of grease and lubricating oil is effective in understanding the operating condition of railway bearings. Of course, the leakage, discoloration, and deterioration of grease or oil can be determined by the moisture, impurities, iron powder, etc. contained in it.

When it is believed that there is lubricant leakage and foreign objects such as iron powder and metal powder are mixed in, the leakage amount, INA bearing temperature, and vibration should be quantitatively observed regularly. If abnormalities are found, early maintenance should be carried out.