Among numerous industrial applications, the 67 series, 68 series, and 69 series thin-walled bearings play a key role with their unique advantages. However, to fully utilize their performance, professional technical support is indispensable. This article will elaborate on the technical points of selection, installation, and maintenance of these three series of thin-walled bearings, providing comprehensive guidance for relevant practitioners.

Selection technical support

1. Operating condition analysis

Accurately grasping the operating conditions of equipment is the basis for selection. The factors to be considered include:

-Speed: If the equipment is in high-speed operation, such as high-speed motors, precision grinding machine spindles, etc., the 68 series is often the preferred choice due to its high precision and good high-speed adaptability; For small fans and light-duty transmission devices with relatively moderate rotational speeds, the 67 or 69 series may be sufficient to meet the requirements.

-Load type and size: When mainly subjected to radial loads, all three series can be considered, but in the case of larger loads, the 69 series will have an advantage due to its relatively excellent radial bearing capacity. If there is an axial load, it is necessary to further analyze its size and direction, and select angular contact ball type thin-walled bearings with appropriate contact angles (corresponding models in these three series) to reasonably share the load.

-Working temperature: Equipment that operates in high-temperature environments, such as certain metallurgical equipment and transmission components of high-temperature ovens, should choose bearing models made of high-temperature resistant materials and with lubricating grease suitable for high-temperature working conditions. At the same time, attention should be paid to the influence of the thermal expansion coefficient of the bearings at high temperatures on the fitting accuracy.

-Installation space limitation: For application scenarios with limited space, such as rotating structures inside medical equipment, cooling fans for small electronic devices, etc., the compact size of the 67 series thin-walled bearings makes them stand out and can achieve reliable support and operation in a limited space.

2. Accuracy level matching

Different industrial applications have varying requirements for bearing accuracy. For example, in the aerospace industry, inertial navigation systems, ultra precision machining machines, etc. require bearings with ultra-high precision levels. High precision specifications in the 68 series can meet such requirements with their extremely small dimensional tolerances and rotational runout; For general industrial transmission equipment, 67 or 69 series bearings with ordinary precision levels can usually ensure the normal operation of the equipment while also considering cost-effectiveness.

Installation technical support

1. Preparation before installation

-Bearing inspection: After receiving the bearing, carefully inspect the appearance for defects such as scratches, bumps, rust, etc., and measure the dimensional accuracy of the bearing with professional measuring tools to ensure that it meets the product standard requirements. In addition, manually rotate the inner or outer ring of the bearing to feel its rotational flexibility, without any jamming or abnormal resistance.

-Preparation of installation tools: Prepare suitable tools according to the size and installation requirements of the bearings, such as specialized bearing installation sleeves, presses, heating devices (for hot installation), etc. For thin-walled bearings, to prevent deformation during installation, auxiliary anti deformation fixtures can be equipped to ensure a smooth and even installation process.

-Clean installation environment: Ensure that the installation site is clean and dry, avoid foreign objects such as dust and impurities from entering the bearings or installation parts, and prevent wear on the bearings or affecting installation accuracy.

2. Key points of installation process

-67 series installation:

-Coordination requirements: The coordination between the shaft and the inner ring of the bearing, as well as between the seat hole and the outer ring of the bearing, usually adopts transitional or interference fit. The appropriate interference fit should be determined based on the specific load and speed conditions. During installation, the cold fitting method (using tools such as a press to evenly apply pressure) can be used. For situations with large interference, it is recommended to use the hot fitting method. Heat the bearing to the appropriate temperature (generally controlled at 80-100 ℃, depending on the bearing specifications and materials) and quickly insert it onto the shaft.

-Special structural treatment: If the bearing has a sealing cover or other structure, attention should be paid to avoiding damage to the sealing components during installation, while ensuring good sealing effect to prevent lubricant leakage and external impurities from entering the interior of the bearing.

-Installation of 68 series:

-High precision positioning: Given that it is commonly used in equipment that requires high precision, special attention should be paid to its coaxiality with related components during installation. The accuracy of bearing installation position can be ensured through positioning pins, specialized fixtures, and other means, ensuring stability and rotational accuracy under high-speed operation.

-Clearance adjustment: Some 68 series bearings require clearance adjustment at the installation site. The clearance adjustment method provided by the manufacturer should be followed, and appropriate measuring tools (such as feeler gauges, specialized clearance measuring instruments, etc.) should be used to accurately measure and adjust the clearance to the specified range to ensure that the bearings can work normally under different working conditions.

-69 series installation:

-Installation of stop groove: For 69 series bearings with stop grooves on the outer ring, when installing stop components (such as retaining springs, etc.), it is necessary to ensure that they are installed firmly and accurately, which can effectively achieve axial positioning and prevent axial movement of the bearing.

-Uniformity of force distribution: Like other series, during installation, it is necessary to ensure that the force applied to the bearing is evenly distributed to avoid bearing deformation or damage caused by excessive local force. This can be achieved through reasonable selection of installation tools, control of pressure direction and intensity, and other methods.

3. Commissioning after installation

-Rotation accuracy detection: Use professional measuring instruments (such as dial indicators, laser interferometers, etc., selected according to accuracy requirements) to detect the rotation accuracy indicators such as radial runout and axial displacement of the installed bearings. Compare the measurement results with the precision standards required by the equipment. If the tolerance range is exceeded, promptly investigate the cause and make adjustments, which may involve reinstalling, fine-tuning the bearing position, or checking the coaxiality of related components.

-No load trial operation: Conduct a trial operation of the equipment in an unloaded state, and determine the appropriate trial operation speed and time (generally determined based on the normal operating speed of the equipment and the characteristics of the bearings, with a trial operation time of not less than 30 minutes). Observe the sound and temperature changes of the bearing during operation. Under normal circumstances, it should run smoothly without any abnormal noise, and the temperature rise should be within a reasonable range (generally not exceeding 30-40 ℃ of the ambient temperature). If any abnormalities occur, the machine should be stopped immediately for inspection, and possible causes such as improper installation, lubrication problems, or quality defects in the bearings should be investigated.

Maintain technical support

1. Lubrication management

-Lubricant selection: Choose the appropriate lubricant type based on the working conditions of the bearing, such as speed, load, temperature, etc. For low-speed, heavy-duty, and relatively stable temperature operating conditions, lubricating grease is a common choice; For high-speed equipment, lubricating oil can provide better lubrication and heat dissipation effects. At the same time, it is necessary to consider the performance indicators of lubricants, such as viscosity, oxidation resistance, wear resistance, etc., to ensure that they can meet the long-term stable operation requirements of bearings.

-Lubrication cycle determination: Taking into account factors such as bearing speed, operating temperature, load conditions, and usage environment, the lubrication cycle is set. Generally speaking, bearings with high speed, high temperature, and heavy load require more frequent lubrication. This can be determined by regularly checking the status of the lubricant (such as color, viscosity changes, etc.), bearing temperature, and operating sound to determine whether lubrication maintenance needs to be carried out in advance.

2. Regular inspection and fault prevention

-Inspection items: Regular comprehensive inspection of bearings, mainly including appearance wear (checking whether there is wear, scratches, pitting, etc. on the rolling elements, inner and outer rings, and cage surfaces), clearance changes (comparing the clearance data during initial installation to determine whether it exceeds the normal range), temperature monitoring (using infrared thermometers and other equipment to detect the operating temperature of bearings and detect abnormal temperature increases in a timely manner), and vibration (using vibration sensors to detect the vibration amplitude, frequency, etc. of bearings during operation, and analyze whether there are potential fault hazards).

-Fault warning and handling: Establish a fault warning mechanism and set reasonable warning thresholds based on inspection data and historical experience. Once a certain indicator is found to be close to or exceed the threshold, in-depth analysis should be conducted in a timely manner to determine the cause of the fault. Common causes of faults include insufficient or deteriorated lubrication, uneven stress caused by improper installation, and bearing fatigue wear. Take corresponding measures for different reasons, such as supplementing or replacing lubricants, readjusting installations, replacing bearings, etc., to avoid further deterioration of the fault and ensure the normal operation of the equipment.

Conclusion

67 series, 68 series, and 69 series thin-walled bearings have wide applications in different industrial fields, and comprehensive and professional technical support is crucial for leveraging their performance advantages, extending their service life, and ensuring reliable equipment operation. Through precise selection, standardized installation, and scientific maintenance, these bearings can better serve various mechanical equipment and contribute to the efficient and stable development of industrial production.