Adjustable clearance ball bearing design method:
Rolling ball bearings are widely used in production and life because of their advantages such as low frictional resistance, quick start, high efficiency, high rotation accuracy, simple lubrication, and easy replacement. However, due to its high manufacturing precision and complicated process, the current standard rolling bearings are produced by special machines and manufactured by specialized factories. Because the original design seldom considered the adjustable link between the rigid parts such as the inner ring, outer ring, and rolling elements of the bearing, the important accuracy index of the bearing, radial clearance, is mainly ensured by machining tolerances. In this way, even if parts of the bearing are machined with a higher-precision machine tool, it is difficult to achieve the required accuracy by directly assembling the method due to the inevitable accumulation error. Generally, it must be selected by measurement and assembled by grouping assembly method, but the accuracy is still limited, so that the price of high-precision bearings remains high. At the same time, when the bearing is in use, the clearance gap caused by the wear can not be compensated, so that the actual service life is reduced and waste is caused. With the development of production, there is an urgent need to solve this technical problem. For this reason, after analyzing and researching, the author has found the main factor that restricts the bearing radial clearance accuracy. Then start from the reasonable design of the bearing structure, design a novel structure, so that the bearing radial clearance can be easily adjusted to solve the above technical problems. After the trial, the effect is good, and the present is a brief introduction.
1, design ideas, working principles and specific structure
As we all know, to adjust the bearing radial clearance, we must change the outer ring, inner ring, rolling body of the three relative positional relationship, the intuitive approach is to make the outer diameter of the inner ring or the inner diameter of the outer ring can change according to need. For ball bearings, one method has been to machine the inner bore of the bearing into a certain taper, and the corresponding journal has also been machined to a corresponding taper. After assembly, the position of the inner ring on the shaft is changed by an additional device on the shaft, so that the inner ring is deformed to cause the outer diameter to change to adjust the bearing clearance. In all fairness, this is a better way to solve the problem to some extent, so it has been followed. However, there are also several obvious deficiencies. First, the amount of adjustment is limited (even very small), and when the gap is large, it will be inadequate. The second is that the spindle needs to be machined with a higher precision taper, and additional adjustment devices must be provided to make the shaft manufacturing process complicated. Third, the inner ring is subject to a great deal of prestress, and is a tensile stress in the circumferential direction, which is extremely unfavorable to the strength of the bearing. Sometimes the inner ring will even “adhere to self-breaking†during the adjustment. From this we can see that this traditional method is not reasonable and there is a great need for improvement.
Anatomy of the bearing structure shows that this part of the inner ring has already been filled with articles that seem to have no potential to be tapped. The rolling body is "iron plate" and obviously "unprofitable." Naturally, we turned our attention to the outer circle. However, this part is really simple and simple, and it cannot be started with conventional ideas. It is necessary to find another way. After meditation, multi-sided seeking advice, repeated scrutiny, and finally made open. Understand that: to change the radial clearance of the bearing, like snoring, not only from the front (radial) forcibly onslaught, but also can be taken from the side (axial) bypass. The premise is that we must break through the shackles of traditional thinking and the restraint of customary forces, and we must dare to innovate. Therefore, it is bold to envisage that the outer ring of the bearing is cut along the cross-section and divided into two parts (reverse thinking, simplification is complicated). The left and right halves can move relative to each other in the axial direction, and then the relative axial displacement of the outer ring is converted into the radial displacement of the rolling body through the interaction between the special surface on the inner ring fairway and the rolling body, and thus the indirect change is received. The effect of the radial position between the ring, the outer ring and the rolling element achieves the purpose of adjusting the clearance. Based on this, we can have the following technical solutions: The outer ring of the rolling bearing is changed from the integral type to the axially-separated combination type, with the double-row rolling elements, and the adjustment gasket set. The radial clearance of the bearing is conveniently adjusted to the required value by increasing or decreasing the thickness of the adjusting gasket at the time of assembly. Finally, the outer sleeve is assembled with the threaded joint as a whole. In the same way, when the bearing is worn out for a period of time, the thickness of the adjusting gasket can also be properly reduced, so that the bad clearance can be easily eliminated and the original accuracy can be restored. To achieve the purpose of repair.
2, the characteristics of the design
(1) Easy processing and manufacturing: Due to the intermediate adjustable link, the tolerance tolerance of the part's processing size can be greatly relaxed, and the reject rate also decreases exponentially. At the same time, the precision requirements for processing machines can be reduced, making it possible to machine high-precision bearings on ordinary precision machines. The technical level of workers can also be appropriately reduced, with certain economic benefits.
(2) Easy assembly and installation: After the outer ring is used as a component, it is easy to adjust the radial clearance of the bearing to an ideal value, and high accuracy can be achieved without using a group assembly method. The installation on the shaft is also very convenient, there is no need to attach other adjustment devices, simplifying the structure of the whole machine.
(3) Improve the stress conditions: The double-row rolling elements can increase the bearing capacity and can withstand the two-way axial force.
(4) Reducing the type of parts: After the outer ring is used as a constituent body type, the rolling elements can be filled on the fairway, so that the retainer can be omitted. This move can also reduce the number of processes and improve the carrying capacity. Power station valve
(5) Convenient maintenance and repair: When the bearing is overrun due to wear, only by appropriately reducing the thickness of the adjusting gasket, the clearance can be reduced, the original precision can be restored, and the service life of the bearing can be prolonged accordingly. In addition, when only individual components are abnormally damaged, it is also possible to replace the damaged parts to repair the bearings. It can even be used as a new one, which is a good method for careful calculation. 1.2 Inadequacies
(1) The step of cutting the inner and outer threads on the outer ring was added. And because of the presence of threads, stress concentration tends to occur, and at the same time, heat 1P treatment becomes difficult.
(2) The axial dimension of the bearing is relatively large, and there is a large fluctuation due to the randomness of the thickness of the adjusted washer.
(3) The outer ring needs to be thickened to increase the material consumption.
The adjustable clearance rolling bearing introduced here has the advantages of novel design, reasonable structure, convenient assembly, and easy maintenance. In particular, after changing the outer ring of the bearing from the integral type to the axially-separated type, the problem of adjusting the bearing clearance can be solved, which can be used by the counterparts. This design idea can also be extended to other types of bearing design. This design is a non-standard bearing design. There are still many deep issues that need to be explored. The inadequacies need to be solved. Really longing for guidance and help from peer experts.