The adjustment and pre-tightening process of the rolling wide slot take up bearings clearance is an effective means to improve the bearing rotation and bearing capacity and reduce the vibration and noise of the transmission system. In the assembly work, the concept should be clarified, the technical requirements of the bearing assembly should be clarified, and at the same time, the control of the temperature rise of the bearing and the maintenance of good lubrication should not be considered. Correctly using this process method can ensure the quality of the rolling bearing assembly.
The assembly of rolling wide slot take up bearings is often done by fitters in assembly and repair work, and the adjustment and preload of rolling bearing clearance is an important part of rolling bearing assembly work. Accurately grasping the process concept of clearance adjustment and preload and correctly using this processing method in old assembly work guarantees the quality of bearing assembly work.
The clearance of a rolling wide slot take up bearings refers to the maximum movement of the other ferrule along the radial or axial direction when one ferrule is fixed, so the clearance is divided into two types: radial clearance and axial clearance. When rolling bearings are assembled, the clearance is too large or too small. If the clearance is too large, the number of rolling elements that bear the load at the same time will decrease, and the load of a single rolling element will increase, thereby reducing the rotation accuracy of the bearings and reducing the service life; if the clearance is too small, the friction will increase.
The heat generated increases and aggravates wear and tear and can also reduce the service life of the wide slot take up bearings. Therefore, many bearings must strictly control and adjust the clearance during assembly.
Preload means that when the bearing is assembled, an axial force is given to the inner or outer ring of the bearing to eliminate the wide slot take up bearings clearance and cause initial deformation at the contact between the rolling body and the inner and outer rings. Preload can improve the rigidity and rotation accuracy of the bearing under working conditions. For bearings with heavy loads and high requirements for rotation accuracy, most of them work in a state of no clearance or even a small amount of interference. In this case, it is necessary to preload the bearing during assembly. Clearance adjustment and preload are usually made by making proper axial relative displacement of the inner ring and outer ring of the bearings .
It is easy to see from the above technological concepts that by adjusting the clearance of rolling wide slot take up bearings , the bearing capacity and rotation accuracy of the bearings can be improved, and the service life of the bearings can be improved. But at the same time, it will increase the friction of the bearing and increase the heat generation. Therefore, good lubrication and heat dissipation must be ensured while the clearance or preload adjusts. If it is improperly adjusted or poorly lubricated, it will, in turn, increase the wear of the bearing and reduce its life. Therefore, to correctly adjust the clearance and preload of rolling bearings.
1. Assembly technical requirements are the fundamental basis for selecting assembly process methods
The adjustment of the clearance of rolling wide slot take up bearings can effectively improve the rotation accuracy of the bearings, improve the bearing capacity of the bearings, prolong the service life of the bearings, and at the same time effectively reduce vibration and noise not all rolling bearings need clearance during assembly. Adjustment. While pre-tightening can improve the bearing rigidity and spin accuracy, at the same time, it will increase the friction, destroy the lubricating oil film and generate a lot of heat. Therefore, the pre-tightened bearing must be forced to lubricate and cool. This method is limited to It is used when the bearing rigidity and rotation accuracy are extremely high. It is a relatively special process method of production. It is used in the assembly of the main shaft of the machine tool, and it is hardly seen in the bearing assembly of other transmission mechanisms.
Whether to adjust the clearance and preload in the assembly of rolling bearings should be determined according to the assembly technical requirements proposed in the technical documents.
Specifically, in the assembly technology In general, for bearings with high speed, heavy load, or high rotation accuracy requirements, there is a requirement to adjust the bearing clearance or preload; otherwise, the bearing clearance will be maintained. Only axial fixation is required during assembly. From the perspective of bearing types, it is necessary to adjust the clearance of tapered roller bearings, angular contact bearings, and thrust bearings. Adjustment; For general low-speed, light-load radial ball bearings, in most cases, it is not necessary to adjust the clearance, but only fix it axially.
2. To meet the requirements of clearance adjustment and preload under thermal equilibrium conditions
The actual ideal working clearance of the rolling wide slot take up bearings is the clearance adjusted after the temperature rise of the bearing is stable. Therefore, the adjustment of the bearing clearance should be carried out in two stages: first, adjust the bearing clearance by following the relevant operating specifications and technical requirements at room temperature until the clearance is appropriate, and you should feel flexible when turning it by hand; then, adjust the adjustment mechanism properly. Back loose (to prevent the bearing from being locked suddenly due to the temperature rise during the test run), carry out the idling test, the idling time from low speed to high speed shall not exceed 2 hours, and the idling time at the highest speed shall not be less than 30 minutes. It should run flexibly and cleanly, with low noise, and the working temperature should not exceed 50°C. Finally, reset and lock the adjustment mechanism.
3. Maintain good lubrication. Good lubrication can cool the bearings and parts on the shaft
After the rolling bearing clearance is adjusted, the friction will increase, and the heat generated will increase the temperature of the entire transmission system. If the heat cannot be dissipated in time, the heat will change the size of the transmission parts, which will affect the change of the rolling bearing clearance, generate more heat, and form a vicious circle. Therefore, for the clearance-adjusted rolling bearing, it is necessary to maintain good lubrication to reduce friction and, more importantly, use the continuously circulating lubricating oil to take away a large amount of heat, control the temperature rise, and achieve the heat balance of the transmission system.
Special attention should also be paid: before the dry running test, it is necessary first to check whether the oil supply to each part of the lubrication system is normal, especially for the preloaded wide slot take up bearings parts; it is necessary to pay special attention to the sufficient supply of lubricating oil and good working condition.
In short, the adjustment and pre-tightening process of the rolling wide slot take up bearings clearance, effectively improving the bearing rotation accuracy and bearing capacity and reducing the transmission system’s vibration and noise. In addition to meeting the general technical requirements for rolling bearing assembly, the bearings temperature should also be considered during operation. The influence of litre and lubrication on the adjustment work, and after the dry running test, careful inspection and secondary adjustment are required. A patient and meticulous working attitude is also indispensable for assembly and maintenance fitters.
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