In order to ensure the long service life of Timken self-aligning ball bearing, which can not meet the general installation and adjustment requirements, the following measures should be taken:
(1) Timken self-aligning ball bearings are grouped according to the size of their interference fit surface, and Timken self-aligning ball bearings are sequentially arranged according to their clearance in each group.
Group the corresponding shaft or seat hole diameters in the same way. The Timken self-aligning ball bearing group with large interference fit surface size is matched with the shaft group or seat hole group with large diameter,
while the Timken self-aligning ball bearing group with small size is matched with the corresponding group with small diameter. In each matched corresponding group, the Timken self-aligning ball bearing with large clearance shall take a tighter fit, and the Timken self-aligning ball bearing with small clearance shall take a looser fit.
As a result of this matching, in the machines installed in the same batch, the fitting interference of Timken self-aligning ball bearing is relatively consistent, which is neither loose nor too tight, and the clearance is relatively uniform, so as to ensure that the prestress of
Timken self-aligning ball bearing after installation is appropriate, and avoid creep, ring expansion crack, impact, vibration or heating caused by improper clearance Failure of abnormal Timken self-aligning ball bearings such as clutching.
(2) The coaxiality of the journal and seat hole at both ends of the support and the perpendicularity with the end face of the support shall be strictly guaranteed to prevent the generation of additional load.
If possible, the mechanical components acting on the load other than Timken self-aligning ball bearing should be slightly away from the easily damaged Timken self-aligning ball bearing at the end. At the same time, the shaft and rotating parts system should operate as smoothly as possible.
The life of bearing is basically divided into fatigue life, service life, wear life and fault life.
1. Fatigue life: the cumulative time before the material of the main moving parts of the bearing Timken Self-Aligning Ball Bearing reaches the limit and causes bearing failure.
Rated dynamic load: the load that the bearing can bear when the service life is 10000 revolutions.
Equivalent dynamic load: refers to the assumed load that the actual load of the imported bearing is converted according to the operating conditions of the determined dynamic load.
2. Service life: it is a general reference to the above three kinds of life. In theory, it refers to the fatigue life of the bearing. Under normal service conditions, it shows the wear life of the bearing. Under abnormal conditions and no manufacturing defects, it represents the failure life.
3. Wear life: the cumulative Timken Self-Aligning Ball Bearing working time before the clearance of the bearing increases to the specified limit due to normal wear. In terms of today’s bearing industry level, the wear life should be > fatigue life, but in fact, the traction motor is just the opposite.
4. Failure life: bearing failure is the accumulated working time before losing working capacity.
Then what is the relationship between bearing lubrication and bearing life? Look at the purpose of bearing lubrication
Purpose of bearing lubrication:
1. Prolong fatigue life.
The rolling fatigue life of imported bearings is prolonged when the rolling contact surface is well lubricated during rotation. This is the great advantage of lubricating bearings, which can increase fatigue life and prolong bearing life.
2. Reduce friction and wear.
The contact parts of the ring, rolling element and retainer constituting the bearing prevent metal contact and reduce friction and wear.
3. Discharge friction heat and cooling
Circulating oil supply method can use oil to discharge the heat generated by friction or the heat transmitted from the outside for cooling. Prevent the bearing from overheating and the lubricating oil from aging.
Colleagues can also prevent foreign matters from invading the interior of the bearing or prevent the bearing from rusting and corrosion.
The selection of imported bearing grease must be considered from the following aspects:
1. Rust resistance
Antirust agents are insoluble in water. The grease shall have good adhesion, and the grease used in the imported bearing must have anti rust effect. And an oil film can be formed on the surface of the steel.
2. Mechanical stability
Cause leakage. The grease will become soft during mechanical processing. The grease will be thrown into the inlet bearing by the bearing seat.
If the mechanical stability of the grease is not enough, the structure of the soap of the grease will be mechanically disintegrated during operation, resulting in the destruction of the grease and loss of lubrication.
3. Oil seal
During the operation of imported bearings, oil seals are necessary to protect imported bearings and lubricants from foreign pollution. No matter sundries or moisture can penetrate into the inlet bearing to prevent damage to it.
Proper device maintenance is an important factor to give full play to the long service life of imported bearings. At the same time, attention must be paid to the cleanliness of bearings, the correctness of the selection of imported bearings and the selection of appropriate devices and maintenance tools.
In addition, the bearing must be protected from contamination by pollutants and moisture, and the correct device and lubrication must be ensured. Therefore, the design of imported bearing arrangement, the condition of oil seal, the type and lubrication cycle of lubricant, and even special maintenance all play the same and important role.
4. Mixed grease
Never mix the two oils if they are incompatible. Usually its consistency will soften, and the imported bearing may be damaged due to the easy loss of grease. If you don’t know which kind of grease the bearing used originally, you must completely remove the old grease inside and outside the imported bearing before adding new grease.
5. Classification of grease
The consistency and lubricating ability of grease are affected by the working temperature. For imported bearings operating at a certain temperature, it is necessary to select grease with correct consistency and good lubricating effect at the same temperature.
Grease is produced in different working temperature ranges, which can be roughly divided into low temperature, medium temperature and high temperature grease. At the same time, it is mainly distinguished according to temperature and working conditions: grease can be classified according to its allowable working temperature.
There is a kind of grease called extrusion resistance or extrusion resistance, and molybdenum disulfide is added. At the same time, additives are added to strengthen the strength of lubricating oil film.
6. Important factors for oil selection
Choose a grease. If the grease is selected incorrectly, all measures to prevent imported bearings are also futile. It is very important that the viscosity of base oil can provide sufficient lubrication effect at the working temperature. The viscosity is mainly affected by the temperature.
It decreases with the increase of temperature, and increases when the temperature decreases. Therefore, it is necessary to know the base oil viscosity at operating temperature. Machinery manufacturers usually specify the use of a certain grease, but most standard greases are applicable to a wide range.
If the direction of vibration and spindle is horizontal or vertical; Cooling condition; Sealing effect; Peripheral environment. The following are several important factors for selecting grease: type of machinery; Type and size of imported bearings; Operating temperature; Workload; Speed range; Working conditions.