Keywords: radial joint bearing; Self lubricating bearings; Structure; improve
1. Existing problems
The 2ZU5/8KMF self-lubricating radial joint bearing is a support bearing on the automatic tilting device of a certain type of helicopter. Its self-lubricating layer is made of DU material, which is pasted onto the inner diameter surface of the outer ring of the bearing with adhesive. It is squeezed between the working surfaces of the inner and outer rings of the bearing through wrapping pressure. During the operation of the bearing, the DU material lubrication layer plays a lubricating role between the inner and outer rings, without the need for additional lubricant. In practical work, due to the normal wear and tear of the bearing self-lubricating layer, the bearing clearance increases. Under sudden changes in temperature, load, and other conditions, the self-lubricating layer detaches from the bonding surface and slides out of the outer diameter end face. If the lubrication layer completely slides out, the bearing will lose its self-lubricating function, and the inner and outer rings will be severely worn and overheated, causing early failure of the bearing and endangering flight safety.
2. Improvement measures
(1) Add anti slip exit edges at both ends of the inner surface of the outer ring (see Figure 1). The thickness of the lubricating layer material is 0.5mm, and the normal wear amount of the lubricating layer material during the service life of the bearing is 0.008-0.01mm. Therefore, retaining edges with a height of 0.3mm and a width of 0.6mm have been added at both ends of the inner surface of the outer ring of the 2ZU5/8KMF bearing. Reduce the width of the lubricating layer by twice the width of the retaining edge from the original foundation, while keeping the remaining structures unchanged. In this way, after compression. The self-lubricating layer material is limited in the middle by the edge of the inner surface of the bearing outer ring, and its thickness is 0.2mm higher than the edge. Even if the thickness decreases due to normal wear during operation, it will not slide out from both sides below the edge.
Improve the interface method at both ends of the self-lubricating layer. Connect the two ends of the lubrication layer using the original simple diagonal joint method. The docking method of changing to a "dovetail" shaped interface (see Figure 2) also effectively avoids the phenomenon of relative sliding of the lubrication layer at the interface.
3. Conclusion
The improved two sets of bearings were subjected to 1 million swing test evaluations on the E06-12 swing testing machine according to the original test outline requirements. After the test, all bearings were inspected and the self-lubricating layer of the bearings was worn normally and in good condition. No sliding out phenomenon; All parameters and appearance quality of the bearing meet the requirements. After more than a year of outdoor use, the improved bearing works well without any lubrication layer slipping out. At the same time, this design improvement has certain guiding significance for solving the problem of lubrication layer sliding out of other types of self-lubricating joint bearings.
2023 November 4th week Marginal product Recommendation:
Plastic Self-lubricating Bearings:
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