The self-aligning roller bearing has two rows of rollers, one common spherical raceway in the outer ring and two raceways in the inner ring, which are inclined to an angle relative to the axis of the bearing. This ingenious structure makes it have automatic alignment performance, so it is not susceptible to the influence of the angle between the shaft and the bearing housing on the error or the bending of the shaft. It is suitable for the occasion where the angle error is caused by the installation error or the bending of the shaft.
Because of the above characteristics, self-aligning roller bearings are widely used in papermaking machinery, deceleration devices, axles of railway vehicles, bearing seat of gear box of rolling mill, rollers of rolling mill, crusher, vibrating screen, printing machinery, woodworking machinery, deceleration machines for various industries, vertical self-aligning bearing with seat, etc.
But in the process of using self-aligning roller bearings, rollers often drop. Today, Xiaobian will give you a detailed analysis and introduction. What causes the rollers drop of widely used self-aligning roller bearings and how to avoid this problem.
I. The influence of cage processing
The cage is usually drilled on the drilling machine, and the drilling is carried out through the positioning of the equal die. It is easy for the roller to fall off from the cage during the test of bearing rotation. In addition, measuring the center diameter of the cage, by measuring the distance control of the measuring column, the force of calipers is different, and the degree of deflection of the support is different (the position of the support in the pocket hole), so the final measurement size can only be used as a reference, and can not effectively reflect the true measurement value of the center diameter. For medium and large bearings, this measurement method has less influence because of its deep edge. For small bearings, because of its shallow edge, greater impact, sometimes the actual center diameter is larger, but the measurement is qualified, such a situation often occurs.
Spherical Roller Bearings
2. Effect of Bearing Ring Processing
1. The influence of small baffle grinding of bearing inner ring
Small retaining edge of bearing inner ring is grinded by fixed distance method, sometimes it is found that there is black skin after grinding of individual small retaining edge. Because of turning, small margin grinding margin or unequal grinding in surface grinding process are small, which results in black skin after grinding. Usually the black skin can be abrasively moved down normally, which causes the thickness of small barrier to be smaller. For the small baffle with shallow depth, the contact area between the end face of the roller and it is small, and the distance of the roller along the inner ring axis increases after grinding of the small baffle, so that the roller can easily come out along the notch.
2. The influence of small sidewall turning on bearing inner ring
The outer diameter of small retaining edge machined by turning bearing inner ring is "-" tolerance according to the requirement of product drawings, usually - 0.35 to - 0.15mm, while the depth dimension of the designed gap is only basic dimension, and there is no tolerance. The actual processing is controlled within (+0.2mm) according to the accuracy tolerance of the present machine tool, while the measurement of the deep notch size is based on the external diameter benchmark of the small baffle. The tolerance of the depth dimension of the oil ditch is controlled according to the current processing industry standard according to (+0.15mm). In this way, for the small baffle with shallow depth (the distance from the outer diameter of the small baffle to the center of the oil ditch), the depth dimension usually does not exceed 3mm. In actual processing, the cumulative overlapping effect of tolerance may occur, resulting in the minimum contact area between the roller end face and the baffle edge. Sometimes the contact area is even close to the oil ditch.
3. The influence of bearing ring raceway grinding
Bearing outer ring grinding raceway grinding, sometimes found that there is still black skin after individual grinding. Due to the reasons of turning and heat treatment, the grinding allowance is small or the outer raceway is deformed, resulting in black skin after grinding. Usually, the outer raceway is over-grinded and the black skin can be moved down normally, so the inner raceway needs undergrinding to realize the normal fitting of the assembly process. As a result, the center diameter of the roller group is offset as a whole, the contact area between the roller and the retaining edge is offset, and the actual contact area is smaller after the notch is offset, so that the roller can easily come out along the notch.
Through the above analysis, we presumably have a very detailed understanding of the reasons for the drop of the self-aligning roller bearings, so that we can find out the reasons effectively and quickly in the process of use, and quickly solve them, and resume normal use as soon as possible.
