How to extend the three principles of NSK imported bearings
How to extend the three principles of NSK imported bearings
2022年4月21日
Analysis of detection technology of NTN imported bearing and shaft fit
Analysis of detection technology of NTN imported bearing and shaft fit
2022年4月21日

Installation method and service environment of Timken imported bearing

  • When Timken bearing rotates alone, it can be rotated by hand after installation. Check the rotation flexibility of the one-way bearing. If there are no following abnormalities, check the power operation.
  • Stuck ———– cause: foreign matter intrusion, scar on rolling part, etc
  • Excessive torque ———– cause: friction of sealing device, too small clearance, installation error, etc.Installation method and service environment of Timken imported bearingInstallation method and service environment of Timken imported bearing
  • Unbalanced rotating torque – cause: incorrect installation, installation error, etc.
  • Timken bearing for large machinery that cannot be turned by hand, it can be started under no-load state first, and then turn off the power immediately for inertial operation. At this time, after confirming that there is no abnormal vibration or noise and the rotation is normal, enter the power operation.
  • When entering power operation, start at low speed and no load and gradually reach the specified operating conditions. The power operation inspection is mainly based on the sound, temperature rise and vibration. The cause shall be found out immediately, and the one-way bearing shall be removed for inspection when necessary.Installation method and service environment of Timken imported bearing
  • For the one-way sound inspection of Timken bearing, generally, a sound stick can be used.Installation method and service environment of Timken imported bearing
  • The temperature inspection of one-way bearing can generally be speculated according to the shell temperature, but it is correct to directly measure the temperature of the outer ring of one-way bearing by using oil hole, etc.
  • The grinding layer, high-temperature layer and two-layer quenching of Timken bearing are treated in molten state. The molten metal molecular flow is evenly coated on the working surface and cooled by the base metal at a very fast speed to form an extremely thin amorphous structure layer. It has high hardness and toughness, but it is only about 10nm, which is easy to be removed in precision grinding.Installation method and service environment of Timken imported bearing
  • The instantaneous high temperature in the grinding area of Timken bearing can make the surface heated to a certain depth (10 ~ 100nm) higher than the tempering heating temperature of the workpiece. When the austenitizing temperature is not reached, with the increase of the heating temperature, the surface layer by layer will produce the microstructure transformation of re tempering or high-temperature tempering corresponding to the heating temperature, and the hardness will also decrease. The higher the heating temperature, the more severe the decrease of hardness.Installation method and service environment of Timken imported bearing
  • Timken bearing when the instantaneous high temperature in the grinding area heats the surface layer of the workpiece above the austenitizing temperature (AC1), the austenitized structure of the layer will be re quenched into martensitic structure in the subsequent cooling process. 
  • For the workpiece with secondary quenching burn, the high-temperature tempering layer with very low hardness must be under the secondary quenching layer. Timken imported bearings must be installed under dry and clean environmental conditions. Before installation, carefully check the machining quality of the mating surface of the shaft and housing, the end face of the shoulder, the groove and the connecting surface. All mating connection surfaces must be carefully cleaned and deburred, and the unprocessed surface of the casting must be cleaned of molding sand.Installation method and service environment of Timken imported bearing
  • Timken imported bearings shall be cleaned before installation and used after drying, and good lubrication shall be ensured. The bearings are generally lubricated with grease or oil. When grease lubrication is used, grease with excellent properties such as no impurities, oxidation resistance, rust prevention and extreme pressure shall be selecInstallation method and service environment of Timken imported bearingted. 
  • The filling amount of lubricating grease is 30% – 60% of the volume of bearing and bearing box, which should not be too much. The double row tapered roller bearing with sealing structure and the shaft connecting bearing of water pump have been filled with grease, which can be directly used by users and can not be cleaned.
  • When installing the bearing, equal pressure must be applied on the circumference of the ferrule end face to press the ferrule in. It is not allowed to directly knock the bearing end face with hammers and other tools to avoid damaging the bearing. Under the condition of small interference, the end face of the bearing ring can be pressed with the sleeve at room temperature, the sleeve can be knocked with a hammer, and the ring can be pressed in evenly through the sleeve. 
  • If it is installed in large quantities, hydraulic press can be used. When pressing in, ensure that the end face of the outer ring and the end face of the housing shoulder, the end face of the inner ring and the end face of the shaft shoulder are pressed tightly, and there is no gap.Installation method and service environment of Timken imported bearing
  • When the interference is large, the bearing can be installed by oil bath heating or inductor heating. The heating temperature range is 80 ℃ – 100 ℃, and the height cannot exceed 120 ℃. At the same time, tighten the bearing with nuts or other appropriate methods to prevent the gap between the ferrule and the shaft shoulder caused by the width contraction of Timken inlet bearing after cooling.Installation method and service environment of Timken imported bearing
  • The clearance of single row tapered roller bearing shall be adjusted after installation. The clearance value shall be determined according to different working conditions and the interference of the fit. If necessary, it shall be determined by test. The clearance of double row tapered roller bearing and water pump shaft connecting bearing has been adjusted at the factory, so it is not necessary to adjust it during installation.Installation method and service environment of Timken imported bearing
  • Timken imported bearings shall be installed with rotation test. First, they shall be used for rotating shaft or bearing box. If there is no abnormality, they can run at no-load and low speed with power, and then gradually increase the rotation speed and load according to the operation, and detect the noise, vibration and temperature rise. If any abnormality is found, they shall stop running and check. Installation method and service environment of Timken imported bearing
  • It can be delivered for use only after the operation test is normal. The speed of NSK bearing is mainly limited by the temperature rise caused by friction heating inside NSK bearing. When the speed exceeds a certain limit, NSK bearing will not continue to rotate due to burns, etc. The limit speed of NSK bearing refers to the limit value of continuous rotation without friction and heating causing burns.Installation method and service environment of Timken imported bearing
  • Therefore, the limit speed of NSK bearing depends on the type, size and accuracy of NSK bearing, as well as various factors such as lubrication mode, quality and quantity of lubricant, material and type of cage, load conditions and so on. Installation method and service environment of Timken imported bearing
  • The limit speed of various NSK Bearings when grease lubrication and oil lubrication (oil bath lubrication) are respectively contained in the size table of each NSK bearing, and its value represents the limit value of speed of NSK Bearings of standard design when rotating under general load conditions (C / P > = 13, FA / FR < = about 0.25). In addition, the lubricant may be superior to other properties according to its type and brand, but it is not suitable for high-speed rotation.
  • When the corrected load condition C / P of the limit speed is less than 13 (i.e. the equivalent dynamic load p exceeds about 8% of the basic rated dynamic load C), or the axial load in the synthetic load exceeds 25% of the radial load, the limit speed shall be corrected with the following formula.
  • The quenched structure of NSK bearing steel consists of quenched martensite, a small amount of insoluble secondary carbides and about 12% ~ 14% residual austenite. Quenched martensite and retained austenite belong to unstable structure. During tempering, the decomposition of martensite shrinks the volume of steel, while the decomposition of retained austenite expands the volume of steel.
Installation method and service environment of Timken imported bearing
  • With the increase of tempering temperature, the transformation and decomposition amount of residual austenite increases. Under the condition of ensuring the hardness required by the process, appropriately increase the tempering temperature to decompose the residual austenite and transform it into martensite structure with large specific volume, which can correspondingly increase the volume of the workpiece, that is, increase the external diameter grinding amount.
  •  Using this method, the parts with NSK bearing ring defects that become waste products under normal grinding conditions can be saved.Installation method and service environment of Timken imported bearing

Installation method and service environment of Timken imported bearing

  • This method is effective for thick and heavy workpieces with large residual austenite content (especially for self-aligning roller bearings). In the actual production, different tempering processes are formulated for parts with different specifications, sizes and thicknesses. 
  • On the premise of ensuring hardness and deformation, the microstructure is fully transformed to produce large bulge, and the grinding amount is increased accordingly to save the waste products. Installation method and service environment of Timken imported bearing
  • After the ina bearing is installed, in order to check whether the installation is correct, the operation inspection shall be carried out. Small machinery can be rotated by hand to confirm whether it rotates smoothly. The inspection items include poor operation caused by foreign matters, scars and indentation, unstable torque caused by poor installation and poor processing of mounting base, excessive torque caused by too small clearance, installation error and sealing friction, etc. If there is no abnormality, the power operation can be started.
  • Large machinery cannot rotate manually, so the power shall be cut off immediately after no-load start, and the machinery idles. Check whether there is vibration, noise, contact of rotating parts, etc. after confirming that there is no abnormality, enter the power operation.cInstallation method and service environment of Timken imported bearing
  • Power operation, starting from no-load and low speed, slowly increase to the rated operation under the specified conditions. During the test run, the inspection items are whether there is abnormal sound, ina bearing temperature change, lubricant leakage or discoloration, etc. If any abnormality is found, stop the operation immediately, check the machinery, and remove the bearing for inspection if necessary.Installation method and service environment of Timken imported bearing
  • Ina bearing temperature can generally be inferred from the external temperature of the bearing pedestal. However, it is more accurate to directly measure the temperature of the bearing outer ring by using the oil hole. The bearing temperature rises gradually from the beginning of operation, and the temperature is usually stable after 1 ~ 2 hours. Installation method and service environment of Timken imported bearing
  • If the bearing is not installed properly, the temperature will rise sharply, resulting in abnormal high temperature. The reasons are too much lubricant, too small bearing clearance, poor installation, excessive friction of sealing device, etc. In the case of high-speed rotation, the wrong selection of INA Bearing Structure and lubrication mode is also the reason.Installation method and service environment of Timken imported bearing
  • The rotating sound of ina bearing is checked with stethoscope, and there are strong metal noise, abnormal sound, irregular sound and other indications of abnormality. The reasons include poor lubrication, poor accuracy of shaft or bearing seat, bearing damage, foreign matter intrusion, etc.Installation method and service environment of Timken imported bearing
  •  The characteristics of the grease in the bearing may be affected after long-term storage of the bearing with sealing ring or dust cover. The bearings removed from the original packaging shall be properly protected to prevent corrosion and pollution.Installation method and service environment of Timken imported bearing
  • The relative humidity of the storage room is no more than 60%, and the temperature changes little. The bearing can be well stored in the original packaging for a long time.Installation method and service environment of Timken imported bearing
  • NSK bearing import configuration method:Installation method and service environment of Timken imported bearing
  • The shaft is supported by two bearings in radial and axial directions. The bearing on one side is called fixed end bearing. It bears radial and axial loads and plays the role of fixing the relative axial displacement between the shaft and the bearing housing. The other side is called the free end, which only bears the radial load and can move relatively in the axial direction.Installation method and service environment of Timken imported bearing
  • The fixed end bearing must be fixed with the shaft and bearing housing at the same time. The more suitable bearings are radial bearings that can bear composite loads, such as deep groove ball bearings, self-aligning roller bearings, double row or paired angular contact ball bearings or tapered roller bearings. 
  • Radial bearing combinations bearing simple radial load, such as cylindrical roller bearings with inner and outer rings without retaining edges, can also be used as fixed end bearings through combination with deep groove ball bearings, four point contact ball bearings or two-way thrust bearings.Installation method and service environment of Timken imported bearing
  •  At this time, the second bearing provides two-way axial positioning, but it must be installed at a certain radial distance from the bearing housing. When the length of the free end bearing changes due to thermal expansion, there will be no extrusion in the bearing.Installation method and service environment of Timken imported bearing
  •  Axial displacement can occur inside the bearing, as well as the bearing ring and bearing seat. Internal factors mainly refer to the three factors that determine the quality of Timken imported bearings, such as structural design, manufacturing process and material quality.Installation method and service environment of Timken imported bearing
  • First, the reasonable design and advanced nature of the structure will lead to longer TIMKEN bearing life. The manufacturing of bearings generally goes through multiple processing processes such as forging, heat treatment, turning, grinding and assembly. The rationality, advanced nature and stability of all the processing technologies will also affect the life of TIMKEN imported bearings.Installation method and service environment of Timken imported bearing
  •  Among them, the heat treatment and grinding processes that affect the quality of Timken imported bearings are often more directly related to the failure of bearings. In recent years, the research on the metamorphic layer of the bearing working surface shows that the grinding process is closely related to the surface quality of Timken imported bearings.Installation method and service environment of Timken imported bearing
  • The metallurgical quality of Timken imported bearing materials was once the main factor affecting the early failure of Timken imported rolling bearings. With the progress of Metallurgical Technology (such as vacuum degassing of bearing steel), the quality of raw materials has been improved.Installation method and service environment of Timken imported bearing 
  • The proportion of raw material quality factor in Timken imported bearing failure analysis has decreased significantly, but it is still one of the main influencing factors of Timken imported bearing failure. Proper material selection is still a factor that must be considered in bearing failure analysis.Installation method and service environment of Timken imported bearing
  • The main task of Timken imported bearing failure analysis is to find out the main factors causing bearing failure according to a large number of background materials, analysis data and failure forms, so as to put forward targeted improvement measures, prolong the service life of Timken imported bearings and avoid sudden early failure of Timken imported bearings.Installation method and service environment of Timken imported bearing
  • For sealed Timken imported bearings, appropriate greaInstallation method and service environment of Timken imported bearingse has been filled during production; For the bearing, a sealing device is also set in the main engine to prevent the leakage of lubricating grease.
  • There is a problem of how much grease should be injected into Timken imported bearings.
  • Too little grease injection is easy to cause lack of grease or dry friction and affect service life. Excessive grease injection will lead to a large amount of grease leakage, which will not only pollute the environment, but also cause waste. It can be seen that the amount of grease injected into Timken imported bearing is the less the better on the premise of ensuring the full lubrication of Timken imported bearing.Installation method and service environment of Timken imported bearing
  • Advantages and disadvantages of grease lubrication under normal working conditions, grease lubrication can be used for most Timken imported bearing applications.Installation method and service environment of Timken imported bearing
  • The advantage of grease is that it is easier to retain in Timken imported bearing configuration, especially in applications where the vertical axis or axis is inclined at a certain angle. The grease also has the function of sealing, which can prevent the influence of pollutants, moisture or moisture on Timken imported bearings. 
  • However, if there is too much grease, it will lead to the increase of bearing working temperature, especially in the application of high speed. In most cases, the Timken inlet bearing can be completely filled with grease only at the initial stage, while the Timken inlet bearing seat is only filled with an appropriate amount of grease and left with a certain free space. Installation method and service environment of Timken imported bearing
  • Before fully reaching the worInstallation method and service environment of Timken imported bearingking speed, the excess grease must be discharged from the bearing during the running in stage, so that an appropriate amount of grease can be left in the Timken inlet bearing. 
  • When the operating temperature drops significantly, it indicates that the grease has run in with the bearing and is evenly distributed in the Timken imported bearing configuration.Installation method and service environment of Timken imported bearing