Diagnosis and management of NTN imported bearings
Diagnosis and management of NTN imported bearings
2022-04-26
Key points of operation inspection after IKO bearing installation
Key points of operation inspection after IKO bearing installation
2022-04-27

New method of SKF imported bearing heating assembly

  • Generally, the space where IKO bearings can be installed is limited. In most cases, the shaft diameter (or bearing inner diameter) is limited by mechanical design or other design. Therefore, the type and size of IKO bearing are determined according to the inner diameter of IKO bearing. Therefore, the main dimension tables of standard IKO bearings are prepared according to the international standard inner diameter dimensions.New method of SKF imported bearing heating assembly
  • There are many sizes and forms of standard bearings. Standard IKO bearings are used in the design of mechanical devices. The nature, size and direction of the load of IKO bearings and the load imposed on the bearings are changeable. In general, the rated base load is shown on the dimension table. However, axial load and radial load are also important factors in selecting suitable IKO bearings. When the sizes of ball and needle roller bearings are the same, needle roller bearings usually have high load capacity and bear large vibration and impact loads.New method of SKF imported bearing heating assembly

After the installation of IKO bearing,SKF imported bearing

  •  in order to check whether the installation is correct, operation inspection shall be carried out. Small machinery can be rotated by hand to confirm whether it rotates smoothly.New method of SKF imported bearing heating assembly
  • 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.New method of SKF imported bearing heating assembly
  • 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.New method of SKF imported bearing heating assembly
  • 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, IKO 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.New method of SKF imported bearing heating assembly
  • The temperature of IKO bearing can generally be inferred from the external temperature of 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.New method of SKF imported bearing heating assembly
  •  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 choice of IKO bearing structure and lubrication mode is also the reason.New method of SKF imported bearing heating assembly
  • The rotating sound of IKO bearing is checked with stethoscope, and there are strong metal noise, abnormal sound, irregular sound and other indications of abnormality. The reasons are poor lubrication, poor accuracy of shaft or bearing seat, bearing damage, foreign matter intrusion, etc. NSK bearing (especially rolling bearing) is divided into two structures with cage and without cage. New method of SKF imported bearing heating assembly
  • Among them, large bearings are generally required to bear large loads, often without cage, but filled with rolling elements between inner and outer raceways. Most small and medium-sized rolling bearings have cages.New method of SKF imported bearing heating assembly
  • In the machining process of NSK bearing, how are the outer ring, inner ring, rolling element and cage of the bearing assembled together. To put it simply, first place the inner and outer rings of the bearing, place the inner ring next to the side, then place the rolling element (put it aside), then adjust the position of the rolling element, and then place the cage. Now we all know that the cage is also involved in the processing of the bearing, so what is the main function of the bearing cage?New method of SKF imported bearing heating assembly

The purpose of the cage is:New method of SKF imported bearing heating assembly

  • And drive the rolling body to roll on the correct raceway;New method of SKF imported bearing heating assembly
  • The cage separates the rolling elements at an equal distance and evenly distributes them on the circumference of the raceway to prevent mutual collision and friction between the rolling elements during operation;New method of SKF imported bearing heating assembly
  • In the release bearing, the rolling element and a ferrule are combined to prevent the rolling element from falling off.
  • The bearing is called the window, which is used to isolate and the rolling element. The pocket clearance makes the cage have a certain amount of activity in the radial and axial directions. The total amount of activity in the radial direction is called the clearance of the cage. In roller cage, there are many structural types and complex shapes. There are many pockets with equal distance on the cage.New method of SKF imported bearing heating assembly
  •  The pocket shape includes spherical, circular, elliptical, rectangular and tooth shape. Its size is larger than the size of the rolling body. The difference between the two is the pocket gap. Sometimes the connecting part between the windows of the rolling cage is called lintel, which plays the role of connecting and increasing the strength of the cage.New method of SKF imported bearing heating assembly

Key points for good use of bearings:New method of SKF imported bearing heating assembly

  • NSK bearing is a kind of precision mechanical support element. Bearing users deeply hope that the bearing installed on the main engine will not be damaged and maintain its dynamic performance within the predetermined service life, but the objective facts are sometimes not satisfactory. Sudden bearing failure accidents will cause heavy losses to users. New method of SKF imported bearing heating assembly
  • Through a large number of failure analysis and research of rolling bearing, it is shown that the short service life or premature loss of accuracy of bearing is caused by material defects or improper manufacturing, but to a considerable extent, it is due to the failure to install and maintain in strict accordance with the service requirements of bearing, or the improper selection of bearing or the actual load exceeding the rated load of bearing itself, resulting in abnormal damage of bearing, for example, The fatigue spalling of bearing parts is largely caused by impurities in the lubricating oil. New method of SKF imported bearing heating assembly
  • It can be seen that in order to realize that the rolling bearing has a longer service life and precision retention period, in addition to requiring the bearing manufacturer to improve the product quality, the bearing users must also use the bearing with scientific methods and procedures, otherwise, the best bearing will die under the harsh and arbitrary use conditions.New method of SKF imported bearing heating assembly
  • The early failure forms of rolling bearing mainly include fracture, plastic deformation, wear, corrosion and fatigue. Under normal conditions, it is mainly contact fatigue.New method of SKF imported bearing heating assembly
  • In order to better use the bearing, the following points should be noted:New method of SKF imported bearing heating assembly
  • Preparation before installation
  • Selection and requirements for installation site
  • The installation site shall be at a distance from lathes, grinders and other mechanical equipment. The site shall be cleaned and kept dry and clean frequently to prevent iron filings, sand, dust and moisture from entering the bearing.New method of SKF imported bearing heating assembly
  • Check the bearing model and prepare the installation tools
  • Check whether the bearing model and size meet the installation requirements, select the appropriate assembly method and prepare the tools and measuring tools for installation according to the structural characteristics of the bearing and the matching parts. New method of SKF imported bearing heating assembly
  • The commonly used installation tools include hand hammer, copper rod, sleeve, special backing plate, screw mosquito fixture, press, etc., and the measuring tools include vernier caliper, micrometer, dial indicator, etc.New method of SKF imported bearing heating assembly
New method of SKF imported bearing heating assembly

New method of SKF imported bearing heating assembly

  • If there are bumps, rust layers, wear debris, sand particles, dust and soil on the assembly surface of NSK bearing and its matched parts, one is that the bearing is difficult to install, resulting in incorrect assembly position; Second, these attachments form abrasives and are easy to wear the working surface of the bearing, affecting the assembly quality. New method of SKF imported bearing heating assembly
  • Therefore, before installation, carefully inspect the surface of journal, bearing housing hole, shoulder end face and the mating surface of connecting parts such as bushing, washer and end cover. If there is any rust layer, file it off with a fine file and polish it with a fine abrasive cloth. At the same time, remove the attachments on the bearing assembly surface and its connecting parts.New method of SKF imported bearing heating assembly
  • Use of NSK Bearings
  • Precautions for use: rolling bearing is a precision component, and its use must be carried out with corresponding caution. No matter how high-performance bearings are used, if they are not used properly, the expected high performance will not be obtained. Precautions for the use of bearings are as follows:New method of SKF imported bearing heating assembly
  • Keep the bearing and its surroundings clean. Even small dust that cannot be seen by the eyes will affect the bearing. Therefore, keep the surrounding clean so that the dust will not invade the bearing.New method of SKF imported bearing heating assembly
  • Use with care. Strong impact on the bearing during use will produce scars and indentation, which will become the cause of the accident. In serious cases, it will crack and fracture, so we must pay attention to it.New method of SKF imported bearing heating assembly
  • Use appropriate operating tools. Avoid replacing with existing tools, and appropriate tools must be used. Such as special sleeve, press, etc.New method of SKF imported bearing heating assembly
  • Pay attention to the corrosion of the bearing. When operating the bearing, the sweat on the hand will become the cause of rust. Pay attention to operate with clean hands and try to wear gloves.New method of SKF imported bearing heating assembly
  • Do not unpack the bearing before the installation preparation is completed to avoid pollution. Wear failure refers to the failure caused by the continuous wear of the metal on the working surface caused by the relative sliding friction between the surfaces. Continuous wear will cause gradual damage to INA Bearing parts, and eventually lead to the loss of bearing dimensional accuracy and other related problems. New method of SKF imported bearing heating assembly
  • Wear may affect the change of shape, the increase of fit clearance and the change of working surface morphology, may affect the lubricant or make it polluted to a certain extent, resulting in the complete loss of lubrication function, so that the bearing loses the rotation accuracy and even cannot operate normally. Wear failure is one of the common failure modes of various bearings. According to the wear form, it can be divided into common abrasive wear and adhesive wear.New method of SKF imported bearing heating assembly
  • Abrasive wear refers to the wear caused by the relative movement of the contact surface due to the extrusion of foreign hard particles or hard foreign matters or wear debris on the metal surface between the bearing working surfaces. It often causes furrow like scratches on the bearing working surface. Hard particles or foreign matters may come from the inside of the host machine or from other adjacent parts of the host system, and are sent into the bearing by the lubricating medium. New method of SKF imported bearing heating assembly
  • INA Bearing accuracy error related knowledge. Adhesive wear refers to the uneven stress on the friction surface due to the micro bulge or foreign matter on the friction surface. When the lubrication conditions are seriously deteriorated, the local deformation and friction micro welding of the friction surface are easy to be caused due to the heat generated by local friction. New method of SKF imported bearing heating assembly
  • In serious cases, the surface metal may be locally melted, and the force on the contact surface will tear the local friction welding point from the substrate and increase the plastic deformation. This cycle of adhesion tear adhesion constitutes adhesive wear. Generally speaking, slight adhesive wear is called scratch and severe adhesive wear is called bite.New method of SKF imported bearing heating assembly
  • Use electric heating instead of acetylene and oxygen heating. The plane electric furnace is designed into a cylindrical electric furnace, named SKF imported bearing electric heater. According to different bearing inner diameters, bearing electric heaters with different powers and specifications can be designed (the scope of application is within the bearing inner diameter) φ 300mm / above). The heating device has the following advantages: uniform and stable heat radiation, no smoke and dust on the surface of the heated SKF inlet bearing, clean and easy to measure and control the SKF inlet bearing temperature.New method of SKF imported bearing heating assembly
  • Infrared thermometer is used to monitor the temperature of the heated SKF imported bearing surface. The heating value of bearing assembly is generally controlled at 100 ℃ ~ 120 ℃. Within this temperature value, the thermal expansion value of bearing steel is large, which is convenient for SKF imported bearing assembly. This temperature value will not change the mechanical performance of the bearing and has high reliability.New method of SKF imported bearing heating assembly
  • To sum up, SKF imported bearing electric heater is better than traditional acetylene oxygen heating, which is an effective method to improve bearing assembly accuracy and work efficiency and reduce labor intensity.New method of SKF imported bearing heating assembly
  • A method to improve the accuracy of SKF imported bearings
  • The precision of 6202 / P2 bearing used in the main shaft of a precision instrument trial produced by a factory still can not meet the requirements. After that, the journal is thickened and a raceway is made on it to replace the inner ring, and the steel balls are accurately measured. Each group of steel balls is made of three particles in size, and the interval of each group of steel balls is close to 120 °. New method of SKF imported bearing heating assembly
  • Due to the addition of a heavy machining surface and a heavy matching surface, the stiffness of the shaft and SKF imported bearing system is improved at the same time, The close equidistant dispersion of the big three and the small three steel balls improves the rotation accuracy of the shaft, so it meets the accuracy requirements of the instrument.New method of SKF imported bearing heating assembly
  • Precision improvement method
  • After the SKF imported bearing is installed in the main engine, if the radial runout of the main shaft is measured, it can be found that the measured value of each revolution has a certain change; During continuous measurement, it can be found that this change will approximately repeat after a certain number of revolutions. The index to measure the degree of change is the cyclic rotation accuracy. New method of SKF imported bearing heating assembly
  • The number of revolutions required for the approximate repetition of the change represents the “quasi period” of the cyclic rotation accuracy. The large magnitude of the change in the quasi period is the poor cyclic rotation accuracy.New method of SKF imported bearing heating assembly
  • If the spindle is properly preloaded and the speed is gradually reduced to close to the compulsory speed, so as to implement the “running in” function of SKF imported bearing, the cyclic rotation accuracy of the spindle can be improved.New method of SKF imported bearing heating assembly
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