Writer: Eric Bearing Limited
The installation of separate bearing can be easily installed on the shaft or bearing seat because the inner ring and the outer ring are convenient. At this point, it should be noted that when the shaft with the inner ring installed is inserted into the bearing box with the outer ring installed, it should be kept concentric as much as possible to prevent the rolling body and the raceway from being scratched.
When installing non-separable bearings where the inner ring of the KOYO bearing is tightly fitted with the shaft and the housing seat of the outer ring is loosely fitted, the installation of the separable bearing can be easily installed on the shaft or the bearing seat due to the inner ring and the outer ring. At this time, it should be noted that when the shaft with the inner ring installed is inserted into the bearing box with the outer ring installed, it should be kept concentric as much as possible to prevent the rolling body and the raceway from being scratched.
When installing the non-separable bearing with tight fit between the inner ring and the shaft of the KOYO bearing and the loose fit of the outer ring bearing seat, you can use a press to install the bearing on the shaft, and then install the shaft and the bearing together in the bearing seat In the hole, if the bearing is small, you can use a soft metal hammer to lightly tap the end surface of the ring to force the bearing to work, but the striking force must be evenly distributed on the bearing ring. When the outer ring of the bearing and the hole of the bearing seat are tightly fitted, and the inner ring and the shaft are loosely fitted, the bearing can be installed on the shaft first.
When the bearing ring and the shaft or bearing seat hole are tightly matched, a special installation sleeve barrel should be used to press the bearing onto the shaft or bearing seat at the same time.
When the size of the KOYO bearing is large, it is difficult to use cold installation due to the large installation force required or the large interference of the bearing under heavy load, so it is necessary to heat the bearing inner ring or bearing seat in advance Then install. During hot installation, the heating temperature should be strictly controlled. KOYO 32215 JR bearings online , pls click here :
When heating bearings, the maximum heating temperature should not exceed 1200C, generally 80~1000C. Bearings with dust caps or seals cannot be heated, otherwise lubricant will be lost. The heating method can use electric induction beauty, oil bath heating and other methods.
In order to choose the most suitable fit, the following must be considered:
1. The direction of the load
2. Load characteristics
3. The size of the load
4. Temperature conditions
5. Installation and disassembly conditions
About KOYO bearings installed in thin-walled bearing housing holes or hollow shafts, you must provide an interference fit that is larger than normal.
Split bearing housings are not recommended for high-precision or tight seat hole matching, otherwise the split bearing housing may cause deformation of the outer ring.
The abnormal sound of KOYO bearings is a new problem and an old one.
It is a new problem because it is a problem exposed in the process of bearing development from low vibration value to quiet direction in recent years, and the quality of bearings is constantly improving.
Said it is an old problem, because in the early pursuit of low vibration, there is no higher requirement for the sound quality of the bearing, but the abnormal sound of the bearing exists objectively. Once the vibration value of the bearing is steadily reduced to a certain level, the abnormal The sound popped out.
For most types of KOYO bearings with low noise, large vibration value and abnormal noise, their vibration peaks are arranged in order from low to high: low noise bearings, bearings with abnormal noise, and large vibration values Bearing.
This shows that the peak value of the vibration acceleration level of the bearing with abnormal sound is between the low noise and the bearing with large vibration value. Therefore, the misjudgment rate of using the vibration effective value to evaluate the abnormal sound of the bearing is high.
Several issues that should be paid attention to after installation of KOYO seated spherical ball bearings
1. Press fit
The inner ring of the outer spherical ball bearing with the seat is tightly fitted with the shaft. When the outer ring and the hole of the bearing seat are loosely matched, the KOYO bearing can be pressed on the shaft with a press, and then the shaft and the bearing are fitted into the bearing hole Inner, an assembly sleeve (copper or mild steel) made of a soft metal material is placed on the end face of the inner ring of the bearing during press fitting.
The outer ring of KOYO bearing fits tightly with the hole of the bearing seat. When the inner ring is loosely fitted with the shaft, the bearing can be pressed into the hole of the bearing seat first. At this time, the outer diameter of the assembly sleeve should be slightly smaller than the diameter of the seat hole.
If the bearing ring and the shaft and the seat hole are tightly fitted, the installation of the inner ring and the outer ring must be pressed into the shaft and the seat hole at the same time. The structure of the assembly sleeve should be able to press the end surfaces of the inner and outer rings of the bearing at the same time.
2. Heating coordination
By heating the bearing or bearing housing, the thermal expansion is used to transform the tight fit into a loose fit installation method. It is a common and labor-saving installation method. This method is suitable for the installation of KOYO bearings with a large interference. Before the hot assembly, the bearing or the separable bearing ring is placed in the oil tank and heated evenly at 80-100 ℃, and then removed from the oil and installed on the shaft as soon as possible. In order to prevent the end face of the inner ring and the shaft shoulder from fitting tightly after cooling, the spherical ball bearing with seat can be axially tightened after cooling. When the outer ring of the bearing is tightly fitted with the bearing seat made of light metal, the hot fitting method of heating the bearing seat can be used to prevent the mating surface from being scratched.
When heating the bearing with the oil tank, there should be a grid at a certain distance from the bottom of the tank, or use a hook to hang the spherical ball bearing with the seat. The KOYO bearing cannot be placed on the bottom of the tank to prevent sunken impurities from entering the bearing or uneven heating. There must be a thermometer in the oil tank, and the oil temperature must be strictly controlled not to exceed 100°C to prevent the tempering effect and reduce the hardness of the ferrule.
(1) Anti-rust performance
The rust inhibitor is preferably insoluble in water. Grease should have good adhesion, grease used in spherical ball bearings with seats must have anti-rust effect. And can form a layer of oil film on the surface of the steel.
(2) Mechanical stability
Cause a leak. During normal operation, the grease becomes soft during machining. Grease will be thrown into the bearing by the bearing seat. If the mechanical stability of the grease is not sufficient, the structure of the soap of the grease will mechanically disintegrate during operation, causing the grease to be destroyed, thereby losing its lubricating effect.
(3) Oil seal
During the operation of the KOYO bearing, the oil seal is necessary to maintain the barrier of the spherical ball bearing and lubricant from external pollution. No matter debris or moisture can not penetrate into the bearing to prevent damage to it. The correct device maintenance is an important factor to play the longest service life of the bearing. At the same time, we must pay attention to the cleanliness of the bearing, the correctness of the bearing selection, and the selection of appropriate equipment and maintenance tools. In addition, the bearings must be protected from contamination by contaminants and moisture, and ensure proper installation and lubrication. Therefore, the design of the bearing arrangement, the condition of the oil seal, the type of lubricant and the lubrication cycle, and even the special maintenance all play the same and important role.
(4) Mixed grease
If two incompatible greases are mixed, never mix incompatible greases. Usually its consistency will become soft, and in the end, the spherical ball bearing with seat may be damaged due to the easy loss of grease. If you do not know which type of grease was originally used in the bearing, you must first completely remove the old grease inside and outside the bearing before adding new grease.
(5) Classification of grease
The consistency and lubricating ability of the grease is affected by the operating temperature. KOYO bearings operating at a certain temperature must select the grease with the correct consistency and good lubrication effect at the same temperature. Grease is produced in different operating temperature ranges and 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 type of grease called squeeze-resistant or squeeze-resistant and the addition of molybdenum disulfide. At the same time, additives are added to strengthen the strength of the lubricant film.
(6) Important factors in choosing grease
Choose a grease, if you choose the wrong grease, all measures to prevent KOYO bearings will be in vain. The viscosity of the base oil can provide sufficient lubricating effect at the working temperature. It is very important that the viscosity is mainly affected by the temperature. It decreases with the temperature rise, and rises when the temperature drops. Therefore, it is necessary to know the viscosity of the base oil at the operating temperature. Machine manufacturers usually specify the use of a certain grease, but most of the specifications of grease are applicable to a wide range.