The use of Grease Plays an Important Role in Timken Bearing Noise Maintenance
The use of Grease Plays an Important Role in Timken Bearing Noise Maintenance
2022年3月22日
Basic Principles of lubricating Oil Selection
Basic Principles of lubricating Oil Selection
2022年3月22日

How to Prolong Bearing life and / or Service Performance

  • First, lubrication is the key. Select appropriate lubrication system and high-quality lubricant. The lubricating oil film separates the oil film surfaces in contact with each other due to load and provides the necessary protection against corrosion and wear. Therefore, the lubricating oil film is indispensable for normal operation of all rotating or reciprocating parts, especially bearings and gears.

 How to Prolong Bearing life and / or Service Performance

  • In case of splash lubrication or circulating lubrication system, the oil film can also transfer heat. Factories often have unnecessary shutdown and deterioration of equipment status due to improper lubrication.
  •  Insufficient oil supply will lead to increased wear and temperature rise, resulting in excessive wear and / or early bearing failure and damage. Excessive lubrication, especially for high-speed equipment, will generate too much heat due to oil agitation, which will lead to chemical deterioration of lubricating oil and bearing damage.How to Prolong Bearing life and / or Service Performance
  • How to Prolong Bearing life and / or Service Performance
  • Proper lubrication and regular maintenance can avoid bearing damage caused by lubrication problems. Ensure reasonable lubrication:How to Prolong Bearing life and / or Service Performance
  • • follow the instructions set by the equipment manufacturer for each equipment;How to Prolong Bearing life and / or Service Performance
  • • when adding grease, it should be filled between the bearing rolling parts and the shell (or retainer) to ensure that sufficient grease enters and the key raceway surface is fully lubricated;How to Prolong Bearing life and / or Service Performance
  • • pay attention to when the bearing should be re greased;How to Prolong Bearing life and / or Service Performance
  • • monitor the indicating instruments of the equipment in order to find the signs of problems as soon as possible, such as temperature fluctuation and / or abnormal high temperature;How to Prolong Bearing life and / or Service Performance
  • • pay attention to equipment noise or abnormal vibration;How to Prolong Bearing life and / or Service Performance
  • • observe the leakage of lubricating oil;How to Prolong Bearing life and / or Service Performance
  • • regularly sample the lubricating oil and check for contamination.How to Prolong Bearing life and / or Service Performance
  • Secondly, if the bearing performance needs to be improved, reasonable adjustment is very important. During assembly or installation, if the internal clearance of the bearing is too large or too small, or in some cases, the preload is too high, it may lead to early damage and shortened bearing life.
  •  In addition to shutdown and expensive maintenance, improper bearing assembly and installation may have more negative effects, such as affecting the operation of other parts and shortening their service life.How to Prolong Bearing life and / or Service Performance
  • Assembly, installation and regular maintenance according to the equipment manufacturer’s manual is a way to prevent problems. If the time is tight, push the adjusting device forward or remove the gasket to correct the loose conical rolling bearing set. On the other hand, if the bearing is adjusted too tightly, it may cause overheating damage and have to replace the bearing.
  •  The process of assembling and installing bearings must be accurate and repeatable, and can be verified after installation. In addition, other part parameters must be considered to optimize the system performance.How to Prolong Bearing life and / or Service Performance
  • In addition, the equipment shall be used according to the requirements of OEM, and appropriate predictive maintenance items shall be set, such as the monitoring of lubricating oil or grease, which shall include fault root cause analysis. In this way, the normal operation time of even problematic equipment can be greatly prolonged.
  • Correct lubrication and maintenance are very important, and correct installation and use are also indispensable. Make full use of the existing condition monitoring equipment for escort. Failure to follow the installation and maintenance requirements will result in equipment failure and constitute a major hidden danger.How to Prolong Bearing life and / or Service Performance
  • Inspection after bearing installation
  • Whether the bearing is installed correctly or not has a direct impact on its service life and the accuracy of the main engine. If it is not installed properly, the bearing will not only have vibration, high noise, low precision and increasing temperature rise, but also be stuck and burned; On the contrary, a good installation can not only ensure the accuracy, but also greatly prolong the service life. After installation, the bearing must be inspected.How to Prolong Bearing life and / or Service Performance
  • The key inspection items are as follows: check the installation position. After the bearing is installed, first check whether the running parts collide with the fixed parts, whether the lubricating oil can flow into the bearing smoothly, and whether the sealing device and axial fastening device are installed correctly.How to Prolong Bearing life and / or Service Performance
  • Check the radial clearance. In addition to installing the bearing with pre interference, check the radial clearance. The deep groove ball bearing can be tested by hand rotation, and it is better to be stable and flexible without vibration and no left-right swing. Cylindrical roller and self-aligning roller bearings can be inspected with a feeler gauge.
  •  Insert the feeler gauge between the roller and the bearing ring, and the insertion depth of the feeler gauge shall be greater than 1 / 2 of the length of the roller. When the radial clearance of the bearing cannot be measured with a feeler gauge, the axial movement of the bearing can be measured instead of the reduction of the radial clearance. Generally, if the bearing inner ring is a conical hole, the axial movement on the conical surface is about 15 times the reduction of radial clearance.
  • The radial clearance of bearings can be adjusted if they are unqualified after installation, such as angular contact ball bearings and tapered roller bearings; Some have been adjusted according to the standard during manufacturing, and can not be adjusted after installation, such as deep groove ball bearing, self-aligning ball bearing, cylindrical roller bearing, self-aligning roller bearing, etc.
  • If this kind of bearing fails to pass the inspection after installation and the radial assembly clearance is too small, it indicates that the matching selection of the bearing is improper or the processing of the assembly part is incorrect. At this time, the bearing must be removed, the cause found out, eliminated and reinstalled. Of course, too much bearing clearance will not work.How to Prolong Bearing life and / or Service Performance
  • Check the tightness between the bearing and the shaft shoulder. Generally, the bearing installed with tight fit and interference must be close to the shaft shoulder. Inspection method:
  • (1) Lighting method. Aim the electric light at the bearing and shaft shoulder and judge the light leakage. If there is no light leakage, the installation is correct; If the light leaks evenly around the shaft shoulder, it means that the bearing is not close to the shaft shoulder, and pressure should be applied to the bearing to make it close; If there is partial light leakage, it indicates that the bearing is installed obliquely. Tap the inner ring of the bearing with a hammer, copper rod or sleeve and install it slowly.
  • (2) Thickness gauge inspection method. The thickness of the thickness gauge shall be 0. 03mm start. During the inspection, try to insert several places on the end face of the bearing inner ring and the whole circumference of the shaft shoulder. If there is a gap and it is very uniform, it indicates that the bearing is not installed in place. 
  • Pressurize the bearing inner ring to make it close to the shaft shoulder; If the increased pressure is not tight, it means that the fillet of the journal fillet is too large and the bearing is stuck. The journal fillet should be trimmed to make it smaller; If it is found that the thickness gauge of the end face of the bearing inner race and some parts of the bearing shoulder can pass, it means that it is not necessary to disassemble, repair and reinstall at this time.
  • If the bearing is installed in the bearing seat hole with an interference fit and the bearing outer ring is fixed by the housing hole shoulder, whether the end face of the outer ring is close to the end face of the housing hole shoulder and whether the installation is correct can also be checked with a thickness gauge.
  • Inspection of thrust bearing after installation
  • When installing the thrust bearing, check the verticality of the shaft ring and the shaft centerline. The method is to fix the dial indicator on the end face of the box shell, make the contact of the dial indicator push on the raceway of the bearing shaft ring, rotate the bearing and observe the pointer of the dial indicator. If the pointer swings, it indicates that the shaft ring is not perpendicular to the shaft centerline. When the dial gauge is deeper, the dial gauge can be used for inspection.
  • When the thrust bearing is installed correctly, its seat ring can automatically adapt to the rolling of the rolling element and ensure that the rolling element is located in the raceway of the upper and lower rings. If it is installed reversely, not only the bearing will not work normally, but also the mating surfaces will be seriously worn. Since the difference between the shaft ring and the seat ring is not obvious, extra care should be taken during assembly to avoid mistakes. 
  • In addition, 0 should be left between the thrust bearing race and the bearing seat hole. 2―0。 5mm clearance is used to compensate the error caused by inaccurate processing and installation of parts. When the center of bearing ring is offset during operation, this clearance can ensure its automatic adjustment, avoid contact friction and make it operate normally. Otherwise, the bearing will be severely damaged.
  • During the test run, check whether the noise, temperature rise and vibration of the bearing meet the requirements. Generally, the working temperature of the bearing should be lower than 90 ℃. If the temperature is too high, the bearing will be heated, annealed or burned, and the service life will be reduced.
How to Prolong Bearing life and / or Service Performance

Precautions for bearing storage and use!

  • Rolling bearing is a kind of precision basic product. Proper storage and reasonable installation will bring satisfactory results to your use. Due to pollution, corrosion, deformation and other factors, the bearing will affect and destroy the original quality of the bearing and can not achieve your expected use effect. Therefore, Yuanda bearing company gives you the following advice:
  • 1、 Preservation: the bearing shall not be exposed in the air. The storage room shall be kept clean and dry. The relative humidity of the inventory air shall not be greater than 55% and the temperature shall be appropriate. 
  • The bearings that are not used temporarily after being folded shall be coated with oil for sealing. It is also avoided to put it together with corrosive substances such as acid, alkali and chemicals.
  • 2、 Transportation: the bearing shall be free from deformation and damage due to collision and falling during transportation.
  • 3、 Cleaning: except for the sealed bearing with double-sided cover, the other bearings are added with antirust oil when leaving the factory. They should be cleaned before use. Usually, immerse the bearing in gasoline mixed with 8-10% mineral oil, hold the inner ring with one hand and rotate the outer ring with the other hand to wash the antirust agent on the bearing surface. The cleaned bearing can not rotate again. After the gasoline volatilizes, inject lubricating oil or grease. Do not stick dust, moisture and sweat, so as not to affect the rotation accuracy and rust.
  • 4、 Loading and unloading: the installed shaft or hole shall be smooth and free of burrs. Carefully measure whether the diameter of the shaft or hole meets the standard, and recognize the bearing datum plane. For the bearing installed on the shaft, the force is only allowed to act on the inner ring. 
  • For the bearing installed in the hole, the force is on the outer ring, and the force shall be evenly distributed on the circumference of the end face of the ferrule. Do not hit it hard on one side to avoid skew bite. Load and unload the bearing with large interference, The bearing must be preheated, and the heating temperature is between 90-100 ℃. Pay more attention to double row spherical roller bearings and single row circular cone bearings, because the inner retaining edge is very thin and the hole will be broken accidentally.
  • 5、 Inspection: after the bearing is installed, it should rotate flexibly without stagnation. In addition, the dimensional accuracy and rotation accuracy of the bearing have been checked before leaving the factory, which can ensure the quality. The marks on the inner and outer rings of the bearing and the black on the chamfer of the bearing ring are caused by the process and inspection methods to ensure the quality. It is purely normal and does not affect the product quality.
Technical requirements for Timken non-standard bearing