Vibration generation in IKO bearing generally speaking, rolling IKO bearing itself does not produce noise. The commonly felt “IKO inlet bearing noise” is actually the sound effect of IKO inlet bearing directly or indirectly vibrating with the surrounding structure. This is why many times the noise problem can be regarded as a vibration problem involving the whole IKO bearing application.
Excitation caused by the change of the number of loaded rolling elements: when a radial load is loaded on an IKO inlet bearing, the number of loaded rolling elements will change slightly during operation, which causes the deviation of the load direction.
But can be reduced by axial preloading, which is loaded on all rolling elements (not applicable to cylindrical roller IKO bearings).
Local damage: due to operation or installation errors, a small number of IKO inlet bearing raceways and rolling elements may be damaged. During operation, rolling over the damaged IKO inlet bearing components will produce a specific vibration frequency. Four major causes of vibration damage of IKO bearing
Vibration frequency analysis can identify damaged IKO bearing components. This principle has been applied to condition monitoring equipment to detect the damage of IKO imported bearing. To calculate the IKO inlet bearing frequency, please refer to the calculation program “IKO inlet bearing frequency”.Four major causes of vibration damage of IKO bearing
Accuracy of relevant parts: under the condition of close fit between IKO imported bearing ring and IKO bearing seat or transmission shaft, IKO bearing ring may be deformed by matching with the shape of adjacent parts. If deformation occurs, vibration may occur during operation.Four major causes of vibration damage of IKO bearing
Pollutants: if operating in a polluted environment, impurities may enter the IKO inlet bearing and be rolled by the rolling element. The vibration degree depends on the quantity, size and composition of the impurity particles being rolled. Although the typical frequency form will not be generated, a disturbing noise can be heard.Four major causes of vibration damage of IKO bearing
Peeling: IKO imported bearing
when Timken imported bearing rotates under load, the raceway surface or rolling surface of inner ring and outer ring presents fish scale peeling phenomenon due to rolling fatigue.Four major causes of vibration damage of IKO imported bearing
Cause: excessive load. Poor installation (non-linear) moment load, foreign matter intrusion and water ingress. Poor lubrication, improper lubricant, improper Timken inlet bearing clearance. The accuracy of Timken imported bearing housing is not good, the rigidity of Timken imported bearing housing is uneven, and the shaft deflection is large, which is caused by rust, erosion point, scratch and indentation (surface deformation phenomenon).Four major causes of vibration damage of IKO imported bearing
Measures: check the load and re study the Timken imported bearing used, improve the installation method, improve the sealing device and prevent rust during shutdown. Use lubricant with proper viscosity and improve lubrication method. Check the accuracy of the shaft and Timken inlet bearing housing. Check the play.
Peeling: it presents a dark surface with slight wear, on which there are several micro cracks up to 5-10m deep from the surface to the inside, and micro peeling occurs in a large range (micro peeling)
Cause: improper lubricant. Foreign matter has entered the lubricant. Poor lubricant causes rough surface. The surface finish of paired rolling parts is not good.IKO imported bearing
Measures: select lubricant to improve the sealing device and improve the surface finish of paired rolling parts.
Fracture: the so-called fracture refers to the fracture of a small part due to the impact or excessive load on the retaining edge of the raceway wheel or the local part of the roller angle.IKO imported bearing
Cause: hit during installation. IKO imported bearing
Measures: improve the installation method (use hot installation and appropriate tool clamp). Correct load conditions. Timken inlet bearing is installed in place to support the retaining edge.Four major causes of vibration damage of IKO imported bearing
Card injury: the so-called card injury is the surface damage caused by the collection of minor burns in the part of the sliding surface injury. Linear scars in the circumferential direction of slide surface and rolling surface. Cycloidal scar on the end face of the roller and the clamping wound on the shaft ring near the end face of the roller.Four major causes of vibration damage of IKO imported bearing
Cause: excessive load and preloading. Poor lubrication. Foreign body bite. Inclination of inner ring and outer ring and deflection of shaft. The accuracy of shaft and Timken imported bearing housing is poor.Four major causes of vibration damage of IKO imported bearing
Action: check the size of the load. The preloading shall be appropriate. Improve lubricants and lubrication methods. Check the accuracy of the shaft and Timken imported bearing housing.Four major causes of vibration damage of IKO imported bearing
Scratch: the so-called scratch is the quotient of re rolling surface and rolling surface. There is surface damage caused by the combination of minor burns caused by rolling slip and oil film thermal crack. Produce surface roughness with adhesion.IKO imported bearing
Cause: improper lubricant for rapid acceleration and deceleration under high speed and light load. Water intrusion
Measures: improve preload, improve Timken inlet bearing clearance, use lubricant with good oil film, improve lubrication method and seal device
Measurement of bearing hole
For the measurement of the bearing hole, the inner diameter gauge can be used to check the reference size on the outer diameter micrometer, and the roundness and cylindricity of the bearing hole need to be measured at the same time. Burning out Timken bearings often reduces the diameter of the bearing hole at the opening and the roundness is out of tolerance, which is extremely unfavorable to the normal operation of Timken imported bearings. Four major causes of vibration damage of IKO imported bearing
If the locating surface of the connecting rod bolt is loose, the Timken inlet bearing cap of the connecting rod will shift, resulting in the out of tolerance of the roundness of the bearing hole. The roundness error of bearing hole should be controlled within the dimensional tolerance, while the cylindricity should be strictly controlled.Four major causes of vibration damage of IKO imported bearing
Measurement of main dimensions of Timken imported bearings
Timken imported bearing thickness: fix the outside micrometer and change the measuring head from plane to spherical surface, which can be used to measure the bearing thickness. The thickness of Timken inlet bearing should generally be controlled within the range of 0.005 ~ 0.010 mm, otherwise the inner diameter of Timken inlet bearing will exceed the tolerance. Timken imported bearing has slight thinning near the opening, which should be paid attention to during measurement.Four major causes of vibration damage of IKO imported bearing
Fit tightness of Timken imported bearing and bearing hole: the fit tightness is guaranteed by the free spring opening and residual surface height of Timken imported bearing. Under the method of measuring the height of the remaining surface: assemble the bearing according to the regulations, deliver Timken to tighten the bolts of the imported bearing cover to the specified torque, loosen one of the bolts, and measure the clearance at the interface of the bearing cover with a feeler gauge, which shall be within the range of 0.05 ~ 0.15mm.Four major causes of vibration damage of IKO imported bearing
Inner diameter of Timken inlet bearing: before measurement, install the Timken inlet bearing according to the regulations and tighten the Timken inlet bearing cover bolts according to the specified torque. Measure with an inner diameter gauge after the reference dimension is measured with an outer diameter micrometer. During measurement, avoid the thinning area. The difference between the inner diameter of Timken inlet bearing and the outer diameter of corresponding journal is the fit clearance.Four major causes of vibration damage of IKO imported bearing
Coaxiality of the main Timken inlet bearing inner hole: the coaxiality error of the main bearing inner hole is mainly caused by the coaxiality error of the bearing hole, and the coaxiality error of the bearing hole is caused by the deformation of the cylinder block.
When the radial circular runout of the main journal is within the specified tolerance, check the bite mark of the main journal and Timken inlet bearing. If the bite mark position of each main Timken inlet bearing is obviously inconsistent, it indicates that the coaxiality error is large, which can be solved by scraping, boring Timken inlet bearing or replacing cylinder body, otherwise it is difficult to ensure the normal operation of the engine.Four major causes of vibration damage of IKO imported bearing
During the use of Koyo imported bearings.
customers often report that the temperature of Koyo imported bearings will be abnormal when they vibrate. According to the technical explanation of Koyo imported bearing group, the factors leading to this are as follows: the temperature of general bearings increases with the increase of the speed of Koyo imported bearings.
The temperature is stable after stable operation for 1-2 hours. There are many main determinants of bearing temperature, such as speed, lubricating oil, load, foreign matter intrusion and so on. If the above conditions are found, the operation must be stopped and necessary inspection measures shall be taken. (Note: under normal circumstances, the bearing will have a natural temperature rise after just lubrication or re lubrication and last for one or two days.)
It is recommended that the customer use a thermal sensor to monitor the working temperature of the bearing at any time. If the temperature of imported Koyo bearing exceeds 125 ℃ for a long time, the service life of the bearing will be reduced. The reasons for the high temperature of Koyo imported bearings include insufficient or excessive lubrication and lubricant.
It contains impurities, excessive load, damaged ring of K bearing, insufficient clearance, etc. If it is not found and handled in time, the bearing will be scrapped. Therefore, it is necessary to continuously monitor the temperature of Koyo imported bearing, whether it is measuring the Koyo imported bearing itself or other important parts. If the operating conditions remain unchanged, any temperature change can indicate that a fault has occurred.
If the imported bearing of Koyo produces abnormal vibration during operation, it is very easy to damage it. Specifically, it includes peeling damage, indentation damage, crack damage, abnormal wear and other damage phenomena.
Therefore, the magnitude of vibration can be measured through the bearing vibration measuring device. The measured value is different due to the service conditions of the imported bearing of Koyo or the installation position of the sensor. It is recommended to record the value during the normal operation of the machine in advance for comparative analysis.
The additional sealing device supported by NTN imported bearing can effectively prevent the invasion of external foreign matters, but this additional sealing device will increase the axial dimension of the mechanism and bring inconvenience to the use, installation and maintenance of NTN imported bearing. At the same time, its sealing performance is also affected by the machining accuracy and line position tolerance of the matching parts of shaft diameter and shell.
The bearing with seal can not only have a good sealing and lubrication environment, but also solve the problems of support parts, but also save the complex lubrication system. Therefore, sealed bearings are recommended for parts with compact structure and strict sealing requirements. The self sealing of NTN imported bearings not only has good dust-proof and sealing effect, but also can maintain good operation without supplying lubricant during bearing operation, reducing maintenance costs.
The self seal of NTN imported bearing is divided into contact seal and non-contact seal according to the structural form. According to the contact form, it can be divided into radial seal and axial seal. According to the structure of the sealing ring, it can be divided into single lip seal and double lip seal. There are two kinds of non-contact seals: with dust cover and rubber seal ring.
The sealing clearance of the dust cover is large, which is only suitable for dust prevention. The sealing clearance of the rubber sealing ring is small, which has a good sealing effect. Contact sealed bearings generally have only rubber sealing rings and auxiliary parts. The lip of the rubber seal ring is in interference contact with the rotating part of the NTN imported bearing with a certain adhesion force, so as to achieve a good dust-proof sealing effect, but its limit speed is low and the friction torque is large.
The essential noise of ina imported bearings is the noise that will still occur in bearings manufactured with modern processing technology, which is determined by the structure of ina imported bearings. The essential noise can be divided into three types: raceway sound, impact sound of rolling body and rolling sound, which are described as follows:
Raceway sound of ina imported bearing and its control method
Raceway sound is a smooth and continuous sound made by the rolling body rolling on the raceway surface when the shaft is running. It is a unique basic sound that occurs in all rolling ina imported bearings. The general bearing sound is the sound of raceway plus other sounds.
The raceway sound of ball bearing is irregular, and its frequency is above 1000Hz. Its main frequency does not change with the speed, but its total sound pressure level increases with the speed.
For ina imported bearings with loud raceway sound, the sound pressure level of raceway sound decreases with the increase of viscosity; For ina imported bearings with low raceway sound, the sound pressure level changes from decrease to increase when the viscosity increases to more than 20mm2 / s.
The greater the rigidity of ina inlet 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.
The methods to control the sound of raceway are: select the imported bearing with low noise ina, that is, the 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.
Impact sound of rolling element and its control method
When a larger type of ball ina imported bearing or cylindrical roller ina imported bearing runs at low speed under pure radial load, due to the small centrifugal force of the rolling element, the rolling element in the non load area will impact the cage or raceway and make noise. But as the speed increases, the sound will disappear.
The control methods of impact sound of rolling elements are: appropriately reduce the radial clearance, and use ina imported bearing with cage with reasonable structure and flexible material.
Rolling sound of ina imported 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 ina imported bearings of larger models, 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. Special processing methods for the outer race raceway can prevent the occurrence of rolling sound. If necessary, this bearing can be selected, or the radial clearance of ina imported bearing can be appropriately reduced, the lubricating grease with excellent performance can be used and the rigidity of parts matching ina imported bearing can be improved.
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