Introduction to the method of preventing the failure of the Endian bearing by lubrication

1. The raceway is peeled off:

It is inclined to peel off the belt on the working surface of the Entine bearing, which indicates that the bearing is working under the inclined state. When the inclination angle reaches or exceeds the critical state, it is easy to form abnormal sharp wear and peeling at an early stage. The main reason is that the installation is poor, the shaft has deflection, the journal and the shell hole have low precision, and the countermeasures are taken to ensure the quality of the bearing installation and improve the axial runout accuracy of the shoulder and the shoulder.

2. Ferrule break:

Fracture failure of ferrules is generally less common and is often caused by sudden overloads. The causes are more complicated, such as raw material defects (bubbles, shrinkage holes), forging defects (overburning), heat treatment defects (overheating), processing defects (partial burns or surface microcracks), host defects (unstable installation, Lack of lubrication, transient overload, etc., may cause the ferrule to break once it is subjected to an overload shock load or severe vibration. Take measures to avoid overload shock loads, select appropriate interference, improve installation accuracy, improve operating conditions, and enhance quality control during bearing manufacturing.

3. The channel is peeled off at a symmetrical position in the circumferential direction:

The symmetrical position spalling shows that the inner ring is spalled around the inner ring, and the outer ring is peeled off in a circumferentially symmetric position (ie, the short axis direction of the ellipse). The reason for this is mainly because the outer hole of the outer shell is too large or the two half are separated. This is particularly evident in camshaft bearings for motorcycles. When the needle bearing is pressed into the elliptical housing hole or the two halves are fastened, the outer ring of the Endian bearing is elliptical, and the clearance in the short axis direction is significantly reduced or even negative.

Under the action of the load, the inner ring rotates to produce circumferential peeling marks, and the outer ring only produces peeling marks at the symmetrical position in the short axis direction. This is the main reason for the early failure of the bearing. After testing the failure of the bearing, the roundness of the outer diameter of the bearing has been changed from 0.8μm to 27μm. This value is much larger than the radial clearance value. Therefore, it can be confirmed that the bearing is working under severe deformation and negative play, and it is easy to form abnormal sharp wear and peeling at the early stage. The countermeasures taken are to improve the machining accuracy of the outer casing hole or to use the two-half separation structure of the outer casing hole as much as possible.

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Ntn tapered roller bearing to adjust the rotation accuracy of regular lubrication maintenance

After the ntn bearing is installed in the main machine, if the radial runout of the tapered roller bearing main shaft is measured, it can be found that the measured value of each revolution has a certain change; when the measurement is continuously performed, it can be found that after a certain number of revolutions, this Changes will repeat approximately. The index for measuring the degree of change is the cyclic rotation precision, and the change approximately repeats the required number of revolutions to represent the "quasi-period" of the cycle rotation accuracy. The magnitude of the magnitude change in the quasi-period is large, that is, the cycle rotation precision is poor. .

1, grease lubrication

Relubrication of ntn bearings is best carried out during planned equipment downtime and is periodically replenished, while removing old grease or extruding old grease through the drain. Wipe the grease fittings clean before adding fresh grease. If the bearing housing does not have a grease fitting, the bearing housing cover or end cap should be opened to remove the old grease and, after cleaning, replenish the same type of fresh grease.

2, lubricating oil lubrication

Regularly check the oil level and oil quality of the lubricating oil. Under normal circumstances, the normal oil level should be within the range of 1/3-2/3 of the equipment oil level window or mark. The oil filling method is oil cup, the oil level shown only represents the oil replenishing capacity, and the bearing tank oil level is to meet the operation requirements. The oil level in the oil cup is less than 1/4 of its total volume.

Check and replenish the oil method, take a small amount of lubricating oil as a sample and compare it with fresh oil. The competent unit can consider the oil quality test to ensure the oil quality is qualified. If the sample looks cloudy, it may be the result of mixing with water, which is commonly referred to as oil emulsification. At this point, the lubricant should be replaced. Installation of the fixed-end front bearing on the shaft: Thoroughly clean the tapered roller bearing with clean cleaning kerosene. For grease lubrication, firstly inject the organic solvent containing 3% to 5% grease into the ntn bearing for degreasing and cleaning. Use a grease gun to fill the bearing with a certain amount of grease (10% to 15% of the bearing space volume); heat the bearing to raise the temperature by 20 to 30 °C, load the bearing into the shaft end with a hydraulic press; press the adapter sleeve on the shaft And axially position the bearing end face with appropriate pressure; wind the belt of the spring balance on the outer ring of the bearing, and check whether the specified preload has a large change by measuring the starting torque (even if the taper rolls The sub-bearings are correct, but the preload is also subject to change due to the deformation of the fit or cage.

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