Due to the complex structure of many machines, multiple sets of bearings are required to be used in combination. A set of rolling bearings is a combination of two bearing structures at the same time. Such as needle roller and thrust cylindrical roller combined bearing, needle roller and thrust ball combined bearing, needle roller and angular contact ball combined bearing, etc.Among them, the most widely used is the roller bearing.Its unique design is a rolling bearing with short cylindrical, conical or drum-shaped rollers as rolling elements. Mainly used in the following fields: textile machinery, printing machinery, automobile industry, household appliances, money detectors.Combination form of combined bearing1. Needle roller and thrust ball combined bearing without inner ring2. Needle roller without inner ring and thrust ball combined bearing with outer cover3. Combination shaft with inner ring needle roller and thrust ball with outer cover4. Needle roller and angular contact ball combination shaft5. Needle roller and three-point contact ball combination bearing6. Combined needle roller and thrust cylindrical roller bearing without inner ring7. Combined needle roller bearing without inner ring and thrust cylindrical roller bearing with outer cover8. Combination bearing with inner ring needle roller and thrust cylindrical roller9. Combination bearing with inner ring needle roller and thrust cylindrical roller with outer cover10. Needle roller and bidirectional thrust cylindrical roller combined bearing11. Combined bearing with flanged needle roller and bidirectional thrust cylindrical roller
How small are miniature bearings?It refers to a single row deep groove ball bearing with an inner diameter of less than 10 mm.So where can it be applied?It is suitable for all kinds of industrial equipment, small rotary motors and other fields with high speed and low noise, such as: office equipment, micro motors, instrumentation, laser engraving, small clocks, soft drives, pressure rotors, dental drills, hard disk motors , Stepper motors, video recorder drums, toy models, computer cooling fans, money counters, fax machines and other related fields.The production process of miniature bearings is more precise than ordinary bearings, and the cost of long-term replacement of miniature bearings is relatively high, so how to prolong the service life of miniature bearings? Xiaoyun, who has many years of experience in the production of miniature bearings, has summarized the following four main points for youIt is important to install miniature bearings correctlyWhether the installation process of the miniature bearing is correct affects the precision, life and performance of the miniature bearing. The correct installation of the bearing requires the design and assembly department to have sufficient research and rich practical experience on the installation process of the miniature bearing. And at the same time, the production operation department should install according to the operation standard.Specific work standard items are usually as follows:1. Cleaning, the bearing and bearing-related components must be carefully cleaned before the bearing is installed2. Check the dimensions of the associated components and the finishing conditions of the supporting parts to see if the process requirements are loaded3. After installation, it is necessary to check the bearing lubricant and whether the basic operating conditions of the bearing are normal.4. External conditions should be monitored during the use of miniature bearings, such as monitoring of temperature, vibration and noise.If the above standards are carried out according to the requirements, it will help to prolong the service life of the miniature bearing. Regular security inspection will help to find potential problems early, prevent unexpected phenomena of the machine, allow the production plan to be realized, and improve the productivity and efficiency of the factory.Micro bearing cleaning methodThe surface of the miniature bearing will be coated with anti-rust oil. We must carefully clean it with clean gasoline or kerosene when using it, and then apply clean high-quality or high-speed and high-temperature lubricating grease before installation and use. The reason for this is simple, because the impact of cleanliness on the life and vibration noise of miniature bearings is very large. But Xiaoyun reminds that the fully enclosed bearing does not need to be cleaned and refueled.Miniature Bearing Grease SelectionSince the grease is made of base oil, thickener and additives, the performance of different types and different grades of greases of the same type is very different, and the allowable rotation limits are different, so be careful when choosing.But here Xiaoyun briefly introduces you to the general principles of choosing grease:The performance of the grease is mainly determined by the base oil. Generally, the low viscosity base oil is suitable for low temperature and high speed; the high viscosity base oil is suitable for high temperature and high load. The thickener is also related to the lubricating performance, and the water resistance of the thickener determines the water resistance of the grease. In principle, greases of different brands cannot be mixed, and even greases with the same thickener will have adverse effects on each other due to different additives. It is a common misconception that more grease is better when lubricating miniature bearings.Relubrication of miniature bearingsRelubrication of bearings During operation, miniature bearings require correct relubrication to perfect their performance. Miniature bearing lubrication methods are divided into grease lubrication and oil lubrication. In order to make the bearing function well, first of all, it is necessary to select a lubrication method suitable for the conditions of use and the purpose of use. If only lubrication is considered, the lubricity of oil lubrication is dominant. However, grease lubricating oil can simplify the characteristics of the structure around the bearing.
How to find a suitable high temperature resistant bearings?1. Heat treatment dimensional stability temperature of bearing steelFor ordinary bearing steel, there is a stable temperature for heat treatment. Below this temperature, the bearing remains dimensionally stable, and the hardness of the bearing steel material also meets the requirements for use.Generally, the stable temperature of heat treatment for bearings is 150 °C.2. Bearing cage temperature rangeUsually steel or brass cages can withstand a relatively large temperature range. The heat-resistant temperature of steel cages can reach 300°C, and brass cages can reach 250°C, but for nylon cages, they can generally withstand -40 to +120°C. temperature range.3.Temperature range of sealsFor enclosed bearings, metal dust caps do not require special consideration of the temperature range. For rubber material seals, this needs to be considered. The working temperature range of nitrile rubber (NBR) is -40～+120℃, it can work stably within 100℃, and it can work at 120℃ for a short time; When working at 230 ℃.4. Permissible temperature range of bearing greaseTemperature is one of the most important factors affecting lubrication life. Grease base oil viscosity decreases with increasing temperature. Based on grease life calculated at 70°C, the life will be reduced by half for every 15°C increase in operating temperature. The allowable working temperature of the bearing for the motor should be the intersection (the narrowest range) of the allowable temperature range of the various components of the bearing, and only within this range can the safe operation of the bearing be guaranteed.Therefore, whether the bearing can operate in a high temperature environment mainly depends on the choice of lubricant, followed by the bearing sealing material (only for closed bearings) and the cage, and finally the bearing steel. In practice, the temperature generally measured in the application is the temperature near the outer ring of the bearing, and the difference between different measurement methods and positions can be up to 15 °C. Generally, the heat dissipation condition of the bearing seat is better than that of the shaft, so the temperature of the inner ring and rolling elements is 5~10 °C higher than that of the outer ring. Therefore, when the test position is outside the bearing outer ring, if the measured temperature is 95°C, the hottest spot temperature of the inner ring may reach 120°C. This temperature has reached the stable heat-resistant temperature of nylon cage, bearing steel and grease, so it is necessary to choose bearing materials with better heat resistance, such as stainless steel bearings or ceramic bearings.
What is bearing preload? Generally, rolling bearings have a certain clearance under working conditions. However, in order to achieve a specific purpose, when configuring the bearing, the bearing can obtain a certain internal load through a certain adjustment method and use it in a negative clearance state. This method of use is called preload.What are the benefits of preload on bearings? For rolling bearings, proper preload can have the following benefits:1. Improve the rotation accuracy. After the bearing is preloaded, the internal clearance is eliminated, and each rolling element bears a certain preload, supporting the ferrule from all directions, which can improve the rotation accuracy, enable the shaft to be positioned correctly in the axial and radial directions, and improve the shaft. Rotational accuracy, such as machine tool spindle bearings and measuring instruments.2. Improve rigidity. The contact between the rolling element and the raceway is elastic contact, and the rolling element can be regarded as a spring. Bearings with clearance are only supported by a few springs in the direction of force. The preloaded bearing is supported by springs in all directions, and has a certain amount of preload, and the number of rollings under the load is more than that of the bearing, so the rigidity can be improved. In ball bearings, the relationship between the contact deformation of the ball and the raceway and the load is nonlinear, and the contact stiffness increases with the increase of the preload.3. Improve bearing life. After preloading, the number of loaded rolling elements increases, the load on each rolling element decreases, and the load can be distributed evenly on each rolling element, so the life of the bearing can be improved.4. Improve bearing damping and reduce noise. Preloading establishes a stable oil film between the rolling elements and the raceways, improves the damping between the rolling elements and the raceways, improves the dynamic characteristics of the support structure and reduces noise.5. Improve the dynamic performance of angular contact ball bearings. In high-speed rotating angular contact ball bearings, proper preload can prevent the gyroscopic rotation of the steel ball, prevent or reduce the revolving slip of the steel ball, and control the spin sliding of the steel ball.6. Inhibit vibration lines and friction and wear. The outer spherical bearing is actually a variant of the deep groove ball bearing. The outer spherical bearing is mainly used to bear the combined radial and axial load mainly based on the radial load, and it is generally not suitable to bear the axial load alone. It is used for vibration-free machining of low-roughness machining machines, or in mechanisms that need to control friction and wear when starting and stopping frequently.7. Control the slip phenomenon of rolling body revolution and rotation. Spherical bearing with seat This type of bearing is also designed to be self-aligning, easy to install, and has a double-structured sealing device, which can work in harsh environments. The bearing seat is generally cast.Bearings with housings are high-precision components made up of grease-sealed deep groove ball bearings and housings of various shapes. The bearing assembly can be directly installed on the main body of the mechanical device through several bolts, has the self-aligning function, can supplement the grease, etc. It is a product that is very easy to install and use.8. Compensate for wear during operation. Bearings will increase in clearance due to wear during operation, which can be compensated by preloading