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This sound is generated by the rotation of the rolling body in the inner and outer rings, including irregular metal vibration sound independent of speed. Generally, the amount of grease added in the bearing is not enough and should be supplemented. If the equipment is shut down for a long time, especially under the low temperature in winter, the bearing sometimes makes a “hissing” sound during operation, which is related to the smaller radial clearance of the bearing and the smaller working cone penetration of the lubricating grease. The bearing clearance shall be properly adjusted and the new grease with larger working cone penetration shall be replaced.
(2) NTN bearing makes a uniform and periodic “Ho Lo” sound in the continuous “Hua Hua” sound. This sound is caused by scars, grooves and rust spots on the rolling element and the inner and outer ring raceways. The period of sound is directly proportional to the speed of the bearing. Bearings should be replaced.
(3) The NTN bearing makes a discontinuous “stem” sound. This sound is caused by the rupture of the cage or inner and outer rings. The machine must be stopped immediately to replace the bearing.
(4) The NTN bearing makes an irregular and uneven “click” sound. This sound is caused by impurities such as iron filings and sand particles falling into the bearing. The sound intensity is small and has nothing to do with the speed. The bearing shall be cleaned, re greased or changed.
(5) The NTN bearing makes a continuous and irregular “rustle”. This sound is generally related to the loose fit between the inner ring and the shaft or the loose fit between the outer ring and the bearing hole, and the sound intensity is large. The matching relationship of the bearing shall be checked, and the problems found shall be repaired in time.
(6) The NTN bearing makes a continuous screech. This sound is caused by poor lubrication of the bearing, dry friction caused by lack of oil, or local contact of the rolling element is too tight, such as deflection of the raceway of the inner and outer rings, too tight fit of the inner and outer rings of the bearing, etc. The bearing shall be inspected in time to find out the problems and deal with them symptomatically.
proper cleaning methods must be selected according to the properties of the surface to be rusted and the current conditions. Solvent cleaning, chemical treatment cleaning and mechanical cleaning are commonly used. After the surface is dry and cleaned, it can be dried with filtered dry compressed air, or dried with a dryer at 120 ~ 170 ℃, or wiped with clean gauze.
1) Immersion method: some small NTN bearings are immersed in antirust grease and a layer of antirust grease is adhered to their surface. The oil film thickness can be achieved by controlling the temperature or viscosity of antirust grease.
2) The brushing method is used for outdoor construction equipment or products with special shapes that are not suitable for soaking or spraying. During brushing, attention should be paid not only to avoid accumulation, but also to prevent missing coating.
3) spray method can not be used to soak some large antirust substances by immersion method. Generally, the filter compressed air of about 0.7Mpa pressure is used for spraying in the clean air area. Spray method is suitable for solvent dilution antirust oil or thin layer antirust oil, but must adopt perfect fire protection and labor protection measures.
Whether the NTN bearing is installed correctly affects the accuracy, service life and performance. Therefore, the design and assembly department shall fully study the installation of NTN bearing. It is hoped that the installation will be carried out according to the operating standards. Items of operating standards are usually as follows:
(1) Clean NTN bearing and bearing related parts
(2) Check the size and finish machining of related parts
(3) . installation
(4) Inspection after installation of NTN bearing
(5) . supply lubricant
It is hoped that the NTN bearing package will be opened just before installation. General grease lubrication, do not clean, directly fill with grease. Generally, it is not necessary to clean the lubricating oil for lubrication. However, NTN bearings for instrument or high-speed use shall be cleaned with clean oil to remove the rust inhibitor coated on NTN bearings. The bearing with rust inhibitor removed is easy to rust, so it can not be placed regardless. Moreover, NTN bearings sealed with grease can be used directly without cleaning.
The installation method of NTN bearing varies according to the bearing structure, fit and conditions. Generally, because it is mostly shaft rotation, the inner ring needs interference fit. Cylindrical bore bearings are usually pressed in with a press or hot installed. In the case of taper hole, it can be directly installed on the taper shaft or installed with sleeve.
When it is installed on the shell, there is usually more clearance fit, and the outer ring has interference. It is usually pressed in by a press, or there is a cold shrinkage fit method for installation after cooling. When dry ice is used as coolant and cold shrinkage is used for installation, the moisture in the air will condense on the surface of NTN bearing. Therefore, appropriate anti rust measures are required.