Talking about the structure characteristics of double row series bearing

The invention of "ball roller bearings" is based on a genius idea, which is a combination of new rolling elements and new assembly methods. All spheres of the traditional rolling "ball" that do not bear the load are removed. This means that 15% of the diameter of the sides of the ball is cut. The result is the so-called ball roller, a flat ball on both sides, which is 30% narrower than the real ball. This significantly saves valuable space.

In addition, such specially shaped "slim" ball rollers and specially developed assembly methods can increase the number of rolling bodies to approximately 90% of the filling space. More rolling elements in the same space allow for higher load ratings for longer product life. This also provides new opportunities to reduce product size and assembly. The dual cage design allows for optimal independent adjustment of the two raceways and is perfectly matched to the application. This ensures maximum load support with minimal bearing size and lower friction.

Rolling bearings fail due to the constant wear of the bearings during the movement. The grease (oil) and the lubrication method are different, which has different effects on reducing the friction and wear of the bearings. Therefore, lubrication technology has become an important part of bearing technology research. Some people refer to grease (oil) as the "fifth part of the bearing" (others are inner ring, outer ring, rolling element, cage).

The resistance to the rotation of the rolling bearing consists of rolling friction, sliding friction and lubricant friction. Rolling friction occurs when the rolling bodies roll on the raceway; the sliding friction occurs on the guide faces of the rolling bodies in the cage, on the rib guide faces of the cage and on the roller end faces and the ferrule ribs in the roller bearings. The friction of the lubricant consists of the internal friction of the lubricant at the contact and the agitation and extrusion of the lubricant. The total friction of a set of bearings, ie the sum of rolling friction, sliding friction and lubricant friction, is the resistance of the impedance bearing movement. The task of studying lubrication technology is to develop different greases (oils) and their lubrication methods to minimize bearing resistance and longest life.

Bearing grease (oil) under common working conditions, foreign advanced industrial countries have completely passed the technology and production, and have formed a series of varieties and batch production capacity. The current main trend is to study the performance of grease under some special circumstances. For example, it is being studied to improve the vacuum stability, creepability and viscosity-temperature performance of perfluoroether grease for aerospace; and, for example, low-temperature grease, although it has good effects in application, its lubrication mechanism does not have a good theory. set forth. For another example, it is studied to use a gaseous lubricant at a high temperature (200 to 4000 degrees).

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Shaft hole sealing repair method

During the use of the bearing, various situations will occur! Shaft hole sealing is a common fault. How to fix it?

     A. Clean the surface of the bearing hole to be repaired with a new 1755 cleaning agent.

     B. Detect the wear depth of the shaft hole. If the wear depth is less than 4 mm in the diameter direction (ie, the radius direction is less than 2 mm), use a power tool to polish the area to be repaired. Note: Do not rub the surface too bright, the rougher the better.

C. Apply a thin layer of Kesaixin 1731 release agent to the outer ring of the bearing to facilitate the disassembly of the bearing in the future.

D, can be put into use after it is fully cured.

E. Apply the repair agent directly to the outer ring of the bearing, but only apply it to the rear half of the outer ring of the bearing. The amount of coating should ensure that there is no glue between the outer ring of the bearing and the shaft hole, and the gap must be filled with a repairing agent.

F. Prepare 2311 antifriction repair agent.

G. Position the bearing.

H. Wipe off the extruded repair agent. Remind again: when pushing the bearing, it should be ensured that the repairing position is not lacking in glue.

I. Push the bearing coated with the repair agent into the shaft hole.

a. The easiest way is to assemble the shaft and the bearing together with the glue. After the accuracy is determined, the repair agent is cured at this position.

b. When possible, use three-point gasket positioning method or make fixture positioning and assembly.

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Reasons for affecting the circularity of the inner ring of a rolling bearing

1. The circularity of the inner ring of the rolling bearing is an important quality index, which directly affects the working accuracy, stability and service life of the bearing. Grinding is usually a semi-finishing or finishing process of the inner ring channel, which plays a decisive role in the roundness of the inner ring channel. The roundness of the inner ring channel grinding depends on the accuracy and dynamics of the grinding process system. In addition to the characteristics, it is also closely related to the process parameters of the grinding. The former has been valued by many scholars and has carried out a lot of research, which has greatly improved the roundness of the inner ring of the grinding inner ring. With the improvement of the precision of the grinding process system and the improvement of the dynamic characteristics, the grinding process parameters become the main factors affecting the roundness. Therefore, the influence of the grinding process parameters on the roundness is studied, and the process parameters are ensured to ensure the bearing channel. The grinding roundness and the optimization of the process parameters for grinding the bearing channel are of great significance.

2. The inner ring of the bearing is usually cut into the grinding mode by variable feed rate. The grinding cycle can be divided into four stages: rapid approach, coarse feed, fine feed and no feed grinding. The main factors affecting the roundness of the grinding bearing channel can be summarized as: (1) the accuracy of the process system during the grinding process, which depends on the accuracy of the grinding machine and the positioning principle of the fixture, structural parameters and accuracy: (2) the process system Dynamic characteristics, especially the balance of the grinding wheel: During the dressing and grinding process, the grinding wheel is unbalanced, which will cause forced vibration. The relative position of the dresser and the grinding wheel and the relative position of the workpiece and the grinding wheel during grinding are different due to the dressing of the grinding wheel. And the difference in the stiffness of the process system in these two different cases makes the surface of the workpiece caused by vibration not round: the grinding process parameters will affect the contact stiffness between the grinding wheel and the workpiece, the wear process of the grinding wheel and the damping characteristics of the vibration of the process system. Therefore, the vibration characteristics of the grinding process are affected, which is ultimately reflected in the geometry (ie roundness) and other surface quality of the grinding workpiece: (3) The original error of the workpiece caused by the elastic deformation of the process system: analysis of the grinding cycle workpiece The variation law of geometric shape error shows that the geometric error of the workpiece after grinding is mainly determined by the stiffness of the process system and grinding. Cutting process parameters, grinding wheel wear speed and original workpiece error? Considering the above influencing factors, when the stiffness and dynamic characteristics of the process system are constant (especially the grinding wheel must be well balanced), the roundness error of the grinding workpiece depends mainly on the grinding process parameters, so the roundness test data can be passed. The stepwise regression modeling, selecting important parameters from multiple process parameters, and gradually introducing regression equations, to establish an optimal regression equation for the relationship between grinding roundness and process parameters.

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Analysis: bearing clearance rate and application of the matching instrument

First, we must attach great importance to the importance of improving the bearing clearance rate

One of the main quality indicators for bearing matching is radial clearance. Radial clearance refers to the total clearance of the inner and outer ring channels and the rolling elements in the diameter direction.

Therefore, the bearing clearance is not only a major parameter for the qualification of the finished bearing after the qualified finished parts are matched, but also an important factor for the normal operation of the bearing. The clearance value does not meet the technical standards, which will affect the reasonable distribution of the load between the rolling elements. The rotation accuracy, vibration value and life of the bearing will be affected. Therefore, it is undoubtedly important to improve and guarantee the clearance rate of the bearing.

Second, analyze the causal relationship of the radial pass rate

In the process of product quality, once the problem is discovered, it is necessary to find the cause immediately. Using the form of causal analysis, we will analyze the low rate of radial clearance.

There are five major factors affecting the quality of bearing clearance. If materials and environmental factors are not considered for the time being, the influence of the testing instruments, process methods and personnel quality on the quality of the bearing clearance can be mainly analyzed. In the past, the matching method of the inner and outer rings of the bearing and the steel ball is to connect the inner and outer ring channels. The diameter deviation is sorted by the instrument, and a certain inner ring channel diameter size value and an outer ring channel diameter size value are calculated according to the standard clearance, and then the corresponding size copper ball is selected, and after the assembly, the shaft is assembled. Test the upper and lower limit values ​​of the axial clearance to the clearance checker. If the technical requirements are not met, the three will be re-matched. As for the radial clearance value of the bearing, it is known by the axial clearance value, which is difficult to ensure accuracy. Because the measured axial clearance value is only the upper and lower limit values, and the upper and lower limit values ​​are different due to the curvature of the channel and the method of each person, the radial qualification rate of the bearing selected by this method is adopted. It is unstable. When the time is high and the time is low, the number of rework is frequent, and the quality of the product cannot be confirmed.

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