Rolling Koyo bearing with low noise requirements
Rolling Koyo bearing with low noise requirements
2022年5月12日
The main cause of INA Bearing burns is due to the poor lubrication of INA Bearing
The main cause of INA Bearing burns is due to the poor lubrication of INA Bearing
2022年5月13日

Selection of quenching oil for IKO bearing parts

IKO bearing parts are mainly quenched and cooled with mineral oil.

  • The quality of heat treatment and quenching of IKO bearing parts mainly depends on the quenching heating conditions and cooling conditions, and the cooling conditions mainly depend on the selection of corresponding quenching oil and cooling technology.
  • Mineral oil is composed of paraffin, bad alkane, aromatic hydrocarbon, paraffin aromatic series hydrogen talking compounds and their derivatives. Due to different composition and refining methods, special quenching oils with different characteristics and different uses are formed.  IKO bearing parts
  • According to the use requirements (including cooling speed, service temperature, brightness, etc.), it can be divided into ordinary quenching oil, fast quenching oil, overspeed quenching oil, graded quenching oil, vacuum quenching oil, fast bright quenching oil and mechanical oil. IKO bearing parts
  • When selecting quenching oil, factors such as material, shape, size, deformation, hardening layer depth, process, brightness and heat treatment equipment of parts to be treated must be fully considered. Excellent quenching oil is made of refined base oil with high thermal stability (generally paraffin base) and various additives that can improve service performance and service life. For rolling IKO bearing parts, during quenching and cooling, the transformation of pearlite type shall be prevented to avoid opaque quenching or local defects such as troostite and soft spots.  IKO bearing parts
  • Therefore, the cooling rate of quenching oil should be greater than the critical cooling rate of IKO bearing steel. However, the cooling speed should not be too large, so as not to cause large internal stress, resulting in cracking and excessive quenching deformation.  IKO bearing parts
  • According to the C curve, the austenite transformation temperature of gcr15iko bearing steel is about 650 ℃ and 450 ℃. Before this temperature, it must be cooled quickly, but at the later temperature, it can be cooled slowly, especially between the starting point of martensite transformation MS and MF.  IKO bearing parts
  • Slow cooling can reduce deformation and cracks, but it can not be too slow. Otherwise, the stable aging of austenite is easy to cause the increase of residual austenite. Therefore, the cooling rate can be higher than the critical cooling rate at 650 ℃ and 450 ℃, and the oil with slow cooling rate after this temperature is quenching oil Under normal conditions. IKO bearing parts
  • It is difficult to determine the critical cooling rate of steel under various conditions due to different field conditions However, in the field, the change trend of critical cooling rate can be judged according to the factors affecting the critical cooling rate, and the quenching oil can be selected accordingly If the quenching temperature is high, the holding time is long, and the original structure is fine, the critical cooling speed will be smaller, which is the quenching oil with small cooling capacity. IKO bearing parts
  • For IKO bearing rings with large wall thickness, if sufficient hardening layer is obtained, the quenching oil should have a faster cooling rate. For thin-walled IKO bearing rings, the quenching oil should have a slower cooling rate. For parts with complex shapes, quenching oil with short steam film stage and fast cooling speed should be selected. IKO bearing parts
  • For IKO bearing rings requiring small deformation, graded quenching oil shall be selected. If the grading temperature of IKO bearing steel ring is above MS point, the cooling speed reaches the critical cooling speed. Generally speaking, the world’s imported bearings such as imported bearings will not be excited. Once that happens. Then we should check it carefully. IKO bearing parts
  • When a radial load is loaded on an inlet bearing, the number of rolling elements bearing the load will change slightly during operation, that is, this causes the deviation of the load direction. The resulting vibration is inevitable, but can be reduced by axial preloading, which is applied to all rolling elements (not applicable to cylindrical roller bearings).Selection of quenching oil for IKO bearing parts
  • Waviness of components
  • When the imported bearing ring is closely matched with the imported bearing seat or transmission shaft, the imported bearing ring may be deformed by matching with the shape of adjacent components. If deformation occurs, vibration may occur during operation. Therefore, it is important to machine the imported bearing pedestal and transmission shaft to the required tolerance.Selection of quenching oil for IKO bearing parts
  • Local damage
  • Due to incorrect operation or installation, a small number of inlet bearing raceways and rolling elements may be damaged. During operation, rolling over the damaged inlet bearing components will produce a specific vibration frequency. Vibration frequency analysis can identify damaged imported bearing components.Selection of quenching oil for IKO bearing parts
  • Vibration behavior in applications
  • In many applications, the stiffness of imported bearings is the same as that of surrounding structures. Due to this feature, as long as the imported bearing (including preload and clearance) and its configuration in application are correctly selected, it is possible to reduce the vibration in application.Selection of quenching oil for IKO bearing parts
  • There are three ways to reduce the vibration of imported bearings
  • Remove critical excitation vibration from application; Restraining the critical excitation vibration between the excitation part and the resonance part; Change the stiffness of the structure, so as to change the critical frequency.Selection of quenching oil for IKO bearing parts
Selection of quenching oil for IKO bearing parts

Excitation caused by the change of the number of loaded rolling elements

  • For example, in high-speed rotating machinery, in addition to the load borne by the rotor weight which is fixed in the direction, there is also the rotating load caused by the unbalanced mass.Selection of quenching oil for IKO bearing parts
  •  If this rotating load is much larger than the fixed load, the combined load is still the rotating load; If the rotating load is much smaller than the fixed load, the composite load is the swing load. No matter rotating load or swinging load, its size and direction are constantly changing. In the variable working state, the load on some ferrules may be rotating load, fixed load or swinging load. This kind of load is called indeterminate load.Selection of quenching oil for IKO bearing parts
  • Swing load and indefinite load should be treated equally with rotating load in terms of fit. Too loose fit will cause damage to the mating surface.Selection of quenching oil for IKO bearing parts
  • Transition fit or interference fit shall be selected for the ferrule rotating relative to the load direction and the shaft or seat hole. The interference size is based on the principle that when the SKF Bearing works under load, the SKF Bearing ring will not produce “creep” on the shaft or the mating surface in the seat hole. Selection of quenching oil for IKO bearing parts
  • When the load is very light or the ferrule rotates occasionally at low speed under the action of heavy load, the transition fit can be selected. At this time, the shaft surface should have high hardness and small surface roughness.Selection of quenching oil for IKO bearing parts
  • For heavy load occasions, it is usually tighter than that in light load and normal load occasions. The heavier the load, the greater the fit interference.Selection of quenching oil for IKO bearing parts

Sometimes the direction and size of the IKO bearing parts

The first is to identify and check the rolling sound of NTN bearing

  • We can use sound detector to check the rolling sound and sound quality of Timken bearing in operation. Because Timken bearing will emit abnormal sound and irregular sound even if there is slight peeling and other damage, it can be distinguished by sound detector to prevent it in advance.
  • Secondly, the vibration of Timken bearing in operation is identified and checked
  • Timken bearing vibration is very sensitive to the damage of Timken bearing. For example, peeling, indentation, corrosion, crack, wear, etc. will be reflected in the vibration measurement of Timken bearing. Therefore, the vibration can be measured by using a special Japanese Timken bearing vibration meter (frequency analyzer, etc.), and the specific situation of abnormality can not be inferred through frequency division. 
  • The measured values are different due to the service conditions of Timken bearing or the installation position of sensor, so it is necessary to analyze and compare the measured values of each machine in advance to determine the judgment standard.
  • After that, check according to the temperature of Timken bearing
  • The temperature of Timken bearing can generally be inferred from the temperature outside the Timken bearing chamber in Japan. It is more appropriate if the outer ring temperature of Timken bearing can be directly measured by oil hole. Usually, the temperature of Timken bearing rises slowly with the start of operation and reaches a stable state after 1-2 hours. The normal temperature of Timken bearing varies with the heat capacity, heat dissipation, speed and load of the machine.
  •  If the lubrication and installation parts are appropriate, the Timken bearing temperature will rise sharply and abnormal high temperature will occur. At this time, the operation must be stopped and necessary preventive measures must be taken. 
  • According to a large number of test data, since the temperature is affected by lubrication, speed, load and environment, the value in the table only represents the approximate temperature range. Using the thermal sensor, the working temperature of Timken bearing can be monitored at any time, and the automatic alarm or stop when the temperature exceeds the specified value can be realized to prevent the occurrence of combustion shaft accident
  • In order to improve the actual fitting accuracy of NTN bearing during installation, it is necessary to accurately measure the fitting surface dimensions of the inner hole and outer circle of NTN bearing by using the measurement methods and tools that do not deform the NTN bearing. NTN bearing
  • All the measurement items related to the inner diameter and outer diameter can be measured, and the measured data can be comprehensively analyzed. Based on this, the dimensions of the installation parts of Japanese NTN bearing that accurately match the shaft and seat hole can be measured. When actually measuring the corresponding size and geometry of the matched shaft and seat hole, it shall be carried out under the same temperature conditions as when measuring NTN bearing.NTN bearing
  • In order to ensure a high actual matching effect, the roughness of the surface of the shaft and seat hole matched with the NTN bearing shall be as small as possible.NTN bearing
  • During the above measurement, two groups of marks indicating the direction of large deviation shall be made on the outer circle and inner hole of NTN bearing and the corresponding surface of shaft and seat hole on both sides close to the assembly chamfer, so as to align the large deviation of matching two sides with the same direction during actual assembly, so that the deviation of both sides can be partially offset after assembly.NTN bearing
  • The purpose of making two groups of orientation marks is to comprehensively consider the compensation of deviation, not only improve the rotation accuracy of the supports at both ends, but also partially eliminate the coaxiality error of the seat hole between the two supports and the journal at both ends. NTN bearing
  • The implementation of surface strengthening measures on the mating surface, such as sand blasting, using a precision plug with a slightly larger diameter to plug the primary inner hole, etc., are conducive to improving the mating accuracy.NTN bearing

The first is to identify and check the rolling sound of NTN bearing

 

  • We can use sound detector to check the rolling sound and sound quality of Timken bearing in operation. Because Timken bearing will emit abnormal sound and irregular sound even if there is slight peeling and other damage, it can be distinguished by sound detector to prevent it in advance.Selection of quenching oil for IKO bearing parts
  • Secondly, the vibration of Timken bearing in operation is identified and checked
  • Timken bearing vibration is very sensitive to the damage of Timken bearing. For example, peeling, indentation, corrosion, crack, wear, etc. will be reflected in the vibration measurement of Timken bearing. Therefore, the vibration can be measured by using a special Japanese Timken bearing vibration meter (frequency analyzer, etc.), and the specific situation of abnormality can not be inferred through frequency division. The measured values are different due to the service conditions of Timken bearing or the installation position of sensor, so it is necessary to analyze and compare the measured values of each machine in advance to determine the judgment standard.Selection of quenching oil for IKO bearing parts
  • After that, check according to the temperature of Timken bearing
  • The temperature of Timken bearing can generally be inferred from the temperature outside the Timken bearing chamber in Japan. It is more appropriate if the outer ring temperature of Timken bearing can be directly measured by oil hole. Usually, the temperature of Timken bearing rises slowly with the start of operation and reaches a stable state after 1-2 hours. The normal temperature of Timken bearing varies with the heat capacity, heat dissipation, speed and load of the machine.Selection of quenching oil for IKO bearing parts
  •  If the lubrication and installation parts are appropriate, the Timken bearing temperature will rise sharply and abnormal high temperature will occur. At this time, the operation must be stopped and necessary preventive measures must be taken. Selection of quenching oil for IKO bearing parts
  • According to a large number of test data, since the temperature is affected by lubrication, speed, load and environment, the value in the table only represents the approximate temperature range. Using the thermal sensor, the working temperature of Timken bearing can be monitored at any time, and the automatic alarm or stop when the temperature exceeds the specified value can be realized to prevent the occurrence of combustion shaft accidentSelection of quenching oil for IKO bearing parts
  • In order to improve the actual fitting accuracy of NTN bearing during installation, it is necessary to accurately measure the fitting surface dimensions of the inner hole and outer circle of NTN bearing by using the measurement methods and tools that do not deform the NTN bearing. NTN bearing
  • All the measurement items related to the inner diameter and outer diameter can be measured, and the measured data can be comprehensively analyzed. Based on this, the dimensions of the installation parts of Japanese NTN bearing that accurately match the shaft and seat hole can be measured. When actually measuring the corresponding size and geometry of the matched shaft and seat hole, it shall be carried out under the same temperature conditions as when measuring NTN bearing.NTN bearing
  • In order to ensure a high actual matching effect, the roughness of the surface of the shaft and seat hole matched with the NTN bearing shall be as small as possible.NTN bearing
  • During the above measurement, two groups of marks indicating the direction of large deviation shall be made on the outer circle and inner hole of NTN bearing and the corresponding surface of shaft and seat hole on both sides close to the assembly chamfer, so as to align the large deviation of matching two sides with the same direction during actual assembly, so that the deviation of both sides can be partially offset after assembly.NTN bearing
  • The purpose of making two groups of orientation marks is to comprehensively consider the compensation of deviation, not only improve the rotation accuracy of the supports at both ends, but also partially eliminate the coaxiality error of the seat hole between the two supports and the journal at both ends. NTN bearing
  • The implementation of surface strengthening measures on the mating surface, such as sand blasting, using a precision plug with a slightly larger diameter to plug the primary inner hole, etc., are conducive to improving the mating accuracy.NTN bearing

Sometimes the direction and size cannot be IKO bearing parts. 

  • For example, in high-speed rotating machinery, in addition to the load borne by the rotor weight which is fixed in the direction, there is also the rotating load caused by the unbalanced mass. Selection of quenching oil for IKO bearing parts
  • If this rotating load is much larger than the fixed load, the combined load is still the rotating load; If the rotating load is much smaller than the fixed load, the composite load is the swing load. No matter rotating load or swinging load, its size and direction are constantly changing. In the variable working state, the load on some ferrules may be rotating load, fixed load or swinging load. This kind of load is called indeterminate load.Selection of quenching oil for IKO bearing parts
  • Swing load and indefinite load should be treated equally with rotating load in terms of fit. Too loose fit will cause damage to the mating surface.Selection of quenching oil for IKO bearing parts
  • Transition fit or interference fit shall be selected for the ferrule rotating relative to the load direction and the shaft or seat hole. The interference size is based on the principle that when the SKF Bearing works under load, the SKF Bearing ring will not produce “creep” on the shaft or the mating surface in the seat hole. When the load is very light or the ferrule rotates occasionally at low speed under the action of heavy load, the transition fit can be selected. At this time, the shaft surface should have high hardness and small surface roughness.Selection of quenching oil for IKO bearing parts
  • For heavy load occasions, it is usually tighter than that in light load and normal load occasions. The heavier the load, the greater the fit interference. Rolling IKO bearing is a mass-produced mechanical part with strict requirements for manufacturing accuracy and high degree of technical specialization. Therefore, for the vast majority of easy to buy IKO bearing varieties, it should be more cost-effective to buy than repair.Selection of quenching oil for IKO bearing parts

 The repair of IKO bearing can only be considered under the following circumstances

  1.  The failure forms of a large number of IKO bearings of the same model used in large factories are mainly the wear, fatigue or fretting abrasion of the rolling surface. In particular, the damaged parts are mostly cages or rolling elements, and the rings or washers still have repair value;Selection of quenching oil for IKO bearing parts
  2.   Large and extra large IKO bearings are on the verge of failure or have failed without major damage to parts, or valuable IKO bearings must try to prolong their effective service life;Selection of quenching oil for IKO bearing parts
  3.   Some IKO bearing varieties that are really difficult to buy have to be repaired without spare parts after failure, especially imported IKO bearings;Selection of quenching oil for IKO bearing parts
  4.   IKO bearing has slight damage, such as slight water rust during storage and slight fretting abrasion during transportation. Such cases are easy to repair and regrettable to discard.Selection of quenching oil for IKO bearing parts
  • In addition to the economy, the repair of IKO bearing also has its technicality, which requires the repairer to fully understand the corresponding technical requirements of IKO bearing and the characteristics of IKO bearing and its parts in structure, technology and materials. Otherwise, it is difficult to ensure that IKO bearing repair has the required effect.Selection of quenching oil for IKO bearing parts
Selection of quenching oil for IKO bearing parts

Sometimes the direction and size of the IKO bearing parts  determined accurately. 

  • For example, in high-speed rotating machinery, in addition to the load borne by the rotor weight which is fixed in the direction, there is also the rotating load caused by the unbalanced mass. IKO bearing parts
  • If this rotating load is much larger than the fixed load, the combined load is still the rotating load; If the rotating load is much smaller than the fixed load, the composite load is the swing load. No matter rotating load or swinging load, its size and direction are constantly changing. In the variable working state, the load on some ferrules may be rotating load, fixed load or swinging load. This kind of load is called indeterminate load.Selection of quenching oil for IKO bearing parts
  • Swing load and indefinite load should be treated equally with rotating load in terms of fit. Too loose fit will cause damage to the mating surface.Selection of quenching oil for IKO bearing parts
  • Transition fit or interference fit shall be selected for the ferrule rotating relative to the load direction and the shaft or seat hole. The interference size is based on the principle that when the SKF Bearing works under load, the SKF Bearing ring will not produce “creep” on the shaft or the mating surface in the seat hole. When the load is very light or the ferrule rotates occasionally at low speed under the action of heavy load, the transition fit can be selected. At this time, the shaft surface should have high hardness and small surface roughness.Selection of quenching oil for IKO bearing parts
  • For heavy load occasions, it is usually tighter than that in light load and normal load occasions. The heavier the load, the greater the fit interference. Koyo bearing is a large-scale Koyo bearing enterprise that started early in Japan’s bearing industry, so its products tend to receive more attention. For ordinary Koyo bearing users, the noise of Koyo bearing is inevitable. Why does Koyo bearing produce noise?
  • First of all, we should know that the sound of Koyo bearing occurs because its rolling element rolls on the raceway surface, which is the basic feature of all Koyo bearings. The spherical Koyo bearing is different. The rolling sound potential of spherical Koyo bearing is irregular. Its dominant frequency does not change with the speed, but its total sound pressure level increases with the speed. For Koyo bearings with loud raceway sound, the sound pressure level of raceway sound decreases with the increase of viscosity;Selection of quenching oil for IKO bearing parts
  •  The sound pressure level of Koyo bearing with low raceway noise changes from decrease to increase when the viscosity increases to more than 20mm2 / s. The greater the rigidity of Koyo bearing pedestal, the lower the total sound pressure level of raceway sound. If the radial clearance is too small, the total sound pressure level and dominant frequency of raceway sound will increase sharply with the decrease of radial clearance. Selection of quenching oil for IKO bearing parts
  • The methods to control the sound of raceway are as follows: select low-noise Koyo bearing, that is, Koyo bearing with small waviness, and carefully select the service conditions. Raceway noise often affects the noise of the whole machinery. Reducing raceway noise can reduce the noise of the whole machinery.Selection of quenching oil for IKO bearing parts
  • Secondly, the impact sound of the rolling element and its control method. When the larger model ball Koyo bearing or cylindrical roller Koyo bearing runs at low speed under pure radial load, the rolling element in the non load area will impact the cage or raceway and make noise due to the small centrifugal force of the rolling element. But as the speed increases, the sound will disappear. The control methods for the impact sound of rolling elements are: appropriately reduce the radial clearance, and use the Koyo bearing with cage with reasonable structure and flexible material.Selection of quenching oil for IKO bearing parts
  • Later, the rolling sound of Koyo bearing and its control method rolling sound is the harsh metal friction sound that can occur in cylindrical roller bearings on all occasions. Most of it occurs in grease lubricated larger Koyo bearings, which is more likely to occur in greases with degraded base oil performance, and almost does not occur in oil lubrication. In addition, it is easy to occur in winter. When bearing pure radial load, it is easy to occur in the case of large radial clearance, and it is easy to occur in a specific speed range with different models and sizes, both continuously and intermittently.Selection of quenching oil for IKO bearing parts
  • Special processing methods for the outer race raceway can prevent the occurrence of rolling sound. If necessary, this kind of Koyo bearing can be selected, or the radial clearance of Koyo bearing can be appropriately reduced, the lubricating grease with excellent performance can be used and the rigidity of parts matching with Koyo bearing can be improved.Selection of quenching oil for IKO bearing parts
  • These are the reasons why Koyo bearings are prone to noise.