Center-Free Slewing Bearing Axial Load Distribution
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Solution Overview
Problem
Large-diameter center-free slewing bearings face issues with twisting and tilting due to bending moments and tilting forces, leading to premature wear and misalignment of races, especially when designed to accommodate large vertical crane loads and space constraints.
Innovation Solution
The introduction of a third axial bearing to support the nose ring and distribute high axial forces, combined with offsetting the two axial bearings on the same end face to enhance torsional robustness and prevent simultaneous canting of thrust bearings, along with a radial bearing arrangement to maintain stability and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If two opposing thrust bearings and two opposing radial bearings are used to clamp the nose ring, then radial separation of raceways is prevented, but tilting and twisting still occur in the area of the thrust bearings
Solution Approach 1:
The thrust bearing support is segmented into multiple bearings arranged at different positions. Instead of relying on a single thrust bearing or symmetric opposing pair, the invention uses multiple thrust bearings (at least three) distributed around the nose ring, with at least two arranged on the same end face at different radial positions. This segmentation allows each bearing to handle localized loads independently, preventing simultaneous tilting of all bearings while maintaining overall radial stability.
2Force
If a high-load-bearing cylindrical roller bearing with large width is used to absorb vertical crane loads, then axial load capacity is increased, but sensitivity to tilting or misalignment of raceways increases
Solution Approach 1:
The single wide thrust bearing is segmented into multiple narrower thrust bearings distributed around the nose ring. Each bearing has a smaller width (rolling element length) than a single wide bearing would require, making them less sensitive to tilting. The collective arrangement of multiple bearings provides equivalent or superior axial load capacity while reducing individual bearing sensitivity to misalignment.
Solution Approach 2:
Different regions of the nose ring are supported by thrust bearings with locally optimized characteristics. Each thrust bearing is positioned and sized according to the local load distribution and geometric constraints, rather than using a uniform wide bearing throughout. This allows each bearing to operate in its optimal performance range with reduced sensitivity to local tilting.
3Volume of moving object
If the bearing rings are designed with limited radial size due to space constraints, then the area moments of inertia of the running rings are limited, but the bearing must still absorb high vertical crane loads
Solution Approach 1:
The load-bearing capability is enhanced by transitioning from a single-dimension (radial) design to a multi-dimensional arrangement. Multiple thrust bearings are positioned at different radial positions and angles around the nose ring, utilizing the circumferential dimension to distribute loads. This spatial distribution allows the bearing to absorb high vertical loads while maintaining compact radial dimensions, as the load path is distributed across multiple contact points rather than requiring a single large radial structure.
Data Source
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AI summary
The invention relates to a rolling-element bearing, in particular a large rolling-element bearing having no center, comprising two concentric running rings, of which the one running ring comprises a groove open toward the other running ring and the other running ring comprises a projection ring that engages in said groove, wherein the projection ring is supported on the groove in the axial direction of the rolling-element bearing by means of at least two axial bearings, which are arranged on opposite projection-ring end faces, and in the radial direction by means of at least one radial bearing, which is arranged on a projection-ring cylindrical surface. According to the invention, the projection ring is supported on the groove in the axial direction by means of a third axial bearing, wherein two axial bearings are arranged on the same side of the projection ring on separate raceways offset from each other in the axial direction of the rolling-element bearing.