I. Vibration of Bearings
Vibration damage of TIMKEN bearings is very sensitive, such as spalling, indentation, rust, crack, wear and tear, etc. can be reflected in vibration measurement. Therefore, the vibration can be measured by using special flange bearing vibration measuring device (frequency analyzer, etc.). The abnormal situation can not be deduced by frequency. The measured values vary with the use conditions of bearings or the installation position of sensors, so it is necessary to analyze and compare the measured values of each machine before determining the judgment criteria.
Two, temperature
Bearing temperature, generally outside the room temperature can be inferred, if the use of oil holes can directly measure the temperature of the outer ring, it is more appropriate.
Usually, the temperature rises slowly with the start of operation and reaches a stable state after 1-2 hours. Normal temperature varies with the heat capacity, heat dissipation, speed and load of the machine. If the lubrication and installation parts are suitable, the temperature will rise sharply and abnormal high temperature will occur. At this time, the operation must be stopped and necessary preventive measures should be taken.
The use of heat sensors can monitor the working temperature at any time, and realize automatic alarm or stop to prevent the occurrence of burning shaft accidents when the temperature exceeds the specified value.
High temperature is often used to indicate abnormal conditions. High temperatures are also harmful lubricants. Sometimes the overheating of flange bearings can be attributed to lubricants. Long-term continuous transfer at temperatures above 125 C will reduce life. Causes of high temperature include: insufficient or excessive lubrication, lubricants. It contains impurities, excessive load loss ring, insufficient clearance, and high friction caused by oil seal, etc.
Secondly, check the condition of raceway surface, rolling surface and mating surface of bearings, as well as the wear condition of cage, etc. without damage and abnormality, especially to observe the track of raceway surface. To judge whether Wuxi bearings can be used again, it is necessary to consider the degree of flange bearing damage, machine performance, importance, operating conditions, inspection cycle and so on.
Inspection results, if found TIMKEN bearing damage and abnormal situation, please according to the phenomenon of bearing damage to identify the causes, formulate countermeasures. In addition, the inspection results show that if there are several defects below, the flange bearings can no longer be used, and new bearings need to be replaced.
A. Any of the inner and outer rings, rolling bodies and cages with cracks and debris.
B. Any one of the inner and outer rings or rolling bodies is peeled off.
C. The surface of raceway, baffle and rolling element have obvious sticking injury.
D. The cage is badly worn or rivets are loosened.
E. Rust and scar on raceway surface and rolling element.
F. There are notable indentations and scratches on the rolling surface and the rolling body.
G. There is creep on the inner diameter or outer diameter of the inner ring.
H. Excessive heat and discoloration.
I. Grease seal TIMKEN bearing seal ring and dust cover damage to serious.
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INA rolling bearing installation basic conditions and daily maintenance points
If there are foreign objects such as iron filings, burrs, dust, etc. in the INA bearing, the rolling bearing will generate noise and vibration during operation, and even damage the raceway and rolling elements. Therefore, before installing the bearings, you must ensure that the mounting surface and the installation environment are clean.
Lubrication has a very important influence on the operation and life of INA bearings. Here is a brief overview of the general principles for selecting greases. Grease is made of base oil, thickener and additives. The grease performance of different types and different grades varies greatly. The allowable rotation limit is different. Be careful when selecting. The performance of grease is mainly determined by the base oil. Generally, the low viscosity base oil is suitable for low temperature, high speed and high viscosity for high temperature and high load. The thickener is also related to the lubricating properties, and the water resistance of the thickener determines the water resistance of the grease. In principle, the different greases of the brand cannot be mixed, and even the grease of the same thickener may have a bad influence on each other due to the different additives.
1) Installation space of rolling bearing Bearing type that can be accommodated in the bearing installation space Since the rigidity and strength of the shaft are important when designing the shafting, the shaft diameter is generally determined first, that is, the inner diameter of the INA bearing. However, rolling bearings are available in a variety of sizes and types, and the most suitable bearing type should be selected.
2) The size, direction and nature of the load bearing load [The bearing capacity of the bearing is expressed by the basic rated load, and its value is shown in the bearing size table] The rolling bearing load is subject to change, such as the magnitude of the load, whether there is only radial load, axial load Whether it is one-way or two-way, the degree of vibration or shock, and so on. After considering these factors, choose the most suitable bearing type.
3) The bearing type whose speed can adapt to the mechanical speed [the limit value of the bearing speed is expressed by the limit speed, and its value is shown in the bearing size table] The limit speed of the INA bearing is not only determined by the bearing type but also the bearing size, cage type, precision. Grades, load conditions, lubrication methods, etc. Therefore, these factors must be considered when selecting.
4) Rotational accuracy Bearing type with required rotation accuracy [The dimensional accuracy and rotation accuracy of bearings have been standardized by GB according to bearing type] Machine spindles, gas turbines and control machines require high rotational accuracy, high speed and low friction, respectively. Rolling bearings with a precision of 5 or more should be used.
5) Rigidity The bearing type that satisfies the rigidity required for the mechanical shafting [When the bearing is subjected to load, the contact portion between the rolling element and the raceway is elastically deformed. "High rigidity" means that the amount of deformation of the elastic deformation is small.] In the machine tool spindle and the final stage of the vehicle, the rigidity of the shaft must be increased, and the rigidity of the bearing must be increased. The rolling bearing is subjected to load deformation smaller than the ball bearing. Applying a pre-tightening (negative clearance) to the INA bearing increases the rigidity. This method is suitable for angular contact ball bearings and tapered roller bearings.
6) The relative inclination analysis of the inner ring and the outer ring makes the inner ring and the outer ring of the bearing relatively inclined (such as the deflection of the shaft caused by the load, the accuracy of the shaft and the outer casing or the installation error), and is selected to adapt to this The type of INA bearing used. If the relative inclination of the inner ring and the outer ring is too large, the bearing may be damaged by internal load. Therefore, you should choose the type of bearing that can withstand this tilt.
7) Installation and disassembly Regular installation and disassembly frequency and assembly and disassembly method When assembling and disassembling frequently, it is convenient to use cylindrical roller bearings with separate inner and outer rings, needle roller bearings and tapered roller bearings. Tapered bore self-aligning ball bearings and tapered bore spherical roller bearings are easy to assemble and disassemble by using fasteners or withdrawal sleeves.
The surface of the rolling bearing is coated with anti-rust oil. You must carefully clean it with clean gasoline or kerosene, and then apply it with clean high-quality or high-speed high-temperature grease. The effect of cleanliness on INA bearing life and vibration noise is very large. But we must remind you that the fully enclosed bearings do not need to be cleaned and refueled.
Lubrication has a very important influence on the operation and life of INA bearings. Here is a brief overview of the general principles for selecting greases. Grease is made of base oil, thickener and additives. The grease performance of different types and different grades varies greatly. The allowable rotation limit is different. Be careful when selecting. The performance of grease is mainly determined by the base oil. Generally, the low viscosity base oil is suitable for low temperature, high speed and high viscosity for high temperature and high load. The thickener is also related to the lubricating properties, and the water resistance of the thickener determines the water resistance of the grease. In principle, the different greases of the brand cannot be mixed, and even the grease of the same thickener may have a bad influence on each other due to the different additives.
1) Installation space of rolling bearing Bearing type that can be accommodated in the bearing installation space Since the rigidity and strength of the shaft are important when designing the shafting, the shaft diameter is generally determined first, that is, the inner diameter of the INA bearing. However, rolling bearings are available in a variety of sizes and types, and the most suitable bearing type should be selected.
2) The size, direction and nature of the load bearing load [The bearing capacity of the bearing is expressed by the basic rated load, and its value is shown in the bearing size table] The rolling bearing load is subject to change, such as the magnitude of the load, whether there is only radial load, axial load Whether it is one-way or two-way, the degree of vibration or shock, and so on. After considering these factors, choose the most suitable bearing type.
3) The bearing type whose speed can adapt to the mechanical speed [the limit value of the bearing speed is expressed by the limit speed, and its value is shown in the bearing size table] The limit speed of the INA bearing is not only determined by the bearing type but also the bearing size, cage type, precision. Grades, load conditions, lubrication methods, etc. Therefore, these factors must be considered when selecting.
4) Rotational accuracy Bearing type with required rotation accuracy [The dimensional accuracy and rotation accuracy of bearings have been standardized by GB according to bearing type] Machine spindles, gas turbines and control machines require high rotational accuracy, high speed and low friction, respectively. Rolling bearings with a precision of 5 or more should be used.
5) Rigidity The bearing type that satisfies the rigidity required for the mechanical shafting [When the bearing is subjected to load, the contact portion between the rolling element and the raceway is elastically deformed. "High rigidity" means that the amount of deformation of the elastic deformation is small.] In the machine tool spindle and the final stage of the vehicle, the rigidity of the shaft must be increased, and the rigidity of the bearing must be increased. The rolling bearing is subjected to load deformation smaller than the ball bearing. Applying a pre-tightening (negative clearance) to the INA bearing increases the rigidity. This method is suitable for angular contact ball bearings and tapered roller bearings.
6) The relative inclination analysis of the inner ring and the outer ring makes the inner ring and the outer ring of the bearing relatively inclined (such as the deflection of the shaft caused by the load, the accuracy of the shaft and the outer casing or the installation error), and is selected to adapt to this The type of INA bearing used. If the relative inclination of the inner ring and the outer ring is too large, the bearing may be damaged by internal load. Therefore, you should choose the type of bearing that can withstand this tilt.
7) Installation and disassembly Regular installation and disassembly frequency and assembly and disassembly method When assembling and disassembling frequently, it is convenient to use cylindrical roller bearings with separate inner and outer rings, needle roller bearings and tapered roller bearings. Tapered bore self-aligning ball bearings and tapered bore spherical roller bearings are easy to assemble and disassemble by using fasteners or withdrawal sleeves.
The surface of the rolling bearing is coated with anti-rust oil. You must carefully clean it with clean gasoline or kerosene, and then apply it with clean high-quality or high-speed high-temperature grease. The effect of cleanliness on INA bearing life and vibration noise is very large. But we must remind you that the fully enclosed bearings do not need to be cleaned and refueled.
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