Rolling bearing is a precise mechanical element that reduces the friction loss by changing the sliding friction between the running shaft and the shaft seat into rolling friction. Rolling bearings are generally composed of four parts: inner ring, outer ring, rolling elements and cage. The function of the inner ring is to cooperate with the shaft and rotate with the shaft; the function of the outer ring is to cooperate with the bearing seat and play a supporting role; Because the cage evenly distributes the rolling elements between the inner ring and the outer ring, its shape, size and number directly affect the performance and life of the rolling bearing; the cage can evenly distribute the rolling elements and guide the rolling elements to rotate for lubrication.

Structure

Rolling bearing

The structure of rolling bearing consists of parts

1. Outer ring - installed in the bearing seat hole, generally does not rotate 2. Inner ring - mounted on the journal and rotates with the shaft 3. Rolling body - the core element of the rolling bearing 4. Cage - evenly spaced the rolling body to avoid friction The fifth largest piece, it mainly plays the role of lubrication, cooling, cleaning, etc.

The bearing problems and preventive measures are as follows:

Failure characteristics

Cause analysis< /p>

Prevention measures

Bearing turns blue or black

1. During use, it was burned due to excessive temperature

2. When the bearing is installed by the heating method, the heating is too high and the bearing is annealed, which reduces the hardness.

1. Pay attention to the installation quality

2. When installing the bearing by the heating method, it should be controlled according to the regulations. Heating temperature

Bearing temperature rise is too high

1. During installation and operation, there are impurities or dirt intrusion

2. Use inappropriate lubricants Or insufficient grease (oil)

3. Friction or loose fit between seals, gaskets, bushings, etc., causing friction

4. Improper installation, such as inner and outer rings Deflection, non-concentric mounting seat holes, raceway deformation and improper clearance adjustment

5. Wrong type selection, when an inappropriate bearing is selected, it will heat up due to overload or high speed

1. Pay attention to installation quality

2. Strengthen maintenance

3. Bearings should be selected according to relevant information

There are abnormal noises during operation

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1. Serious peeling of rolling elements or raceways, uneven surface

2. Improper installation of bearing parts, looseness and friction of bearing accessories

3. Lack of lubricant

4. There are iron filings or dirt in the bearing

1. Pay attention to the installation quality

2. Add lubricant regularly as required

Severe wear of the rolling elements

1. The bearing is subjected to improper axial load

2. The rolling elements are installed skewed

3. The lubricant is too thick

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4. The rolling elements do not roll, resulting in sliding friction, resulting in wear and tear

5. The bearing temperature rises too high, causing damage to the rolling elements

6. Mechanical vibration or bearing Improper installation, the rolling elements are crushed

7. The bearing manufacturing accuracy is not high, the heat treatment is improper, the hardness is low, and the rolling elements are ground into a polygonal shape

1. Ensure the installation as required Quality

2. Use lubricants as specified, or replace lubricants regularly

3. Pay attention to use and maintenance

Scars appear on raceways

1. Metal peeling, rust

2, lack of lubricant

3, improper use of materials

4, bearing impact load Load

5. The current passes through the bearing, resulting in local high temperature and the metal melts.

1. Select the bearing correctly according to the working performance of the bearing

2. Lubricating oil

3. Electricity leakage of electrical equipment is strictly prohibited, and the machine must have a grounding device.

There are cracks in the inner and outer rings of the bearing

1. The matching surface of the journal or bearing seat hole Poor contact, there are gaps in the stressed parts of the raceway, the bearing is subjected to large and uneven force, resulting in fatigue cracks

2. Improper disassembly and assembly, knocked during installation

3. Bearing clearance Shock and vibration caused by grinding

4. The bearing manufacturing quality is poor, and there are cracks inside.

1. Ensure the installation quality as required

2. Replace the worn bearings in time

3. Strictly check the manufacturing quality of the bearing

Bearing metal spalling

1. The bearing is subjected to impact force and alternating load and the contact stress on the surface of the rolling element changes repeatedly

2. The inner and outer rings are installed skewed, the axial matching step is not vertical, and the shaft hole is not concentric

3. The bearing clearance is adjusted too tightly

4. The bearing fits Iron filings or hard dirt fall between the surfaces

5, the journal or bearing seat hole is oval, causing the raceway to be overburdened locally

6, the selected substitute The bearing model does not meet the regulations

1. Ensure the installation quality as required

2. Use the bearing correctly

3. Be careful not to drop iron filings and other dirt Into the bearing

4. Correctly select the bearing.

The rolling element is crushed, which mostly occurs in the thrust bearing.

1. The installation clearance is too small, and the extrusion force Too large

2. Severe impact during use

3. Dirt such as hard iron filings mixed in the lubricant

4. The rolling element originally had cracks Or the bearing runs for too long

1, adjust the clearance reasonably

2, pay attention to the cleanliness of the lubricant

3, replace or repair the bearing according to the specified time

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The hand does not turn after installation

1. The bearing is not clean, and there are sand or iron filings between the rolling element and the raceway

2. The cage is deformed and rolled The body touches the bearing ring

3, the fit between the bearing and the shaft (or the shell hole) is too tight (the interference is too large, the bearing clearance is reduced) or the original bearing clearance is too small

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