Asymmetric Roller Bearing Seal Design for Bowing Reduction
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Solution Overview
Problem
Conventional roller bearing seals face issues with bowing due to thermal and mechanical stresses, leading to reduced sealing effectiveness and load-carrying capacity, as they tend to become non-round and conical, which affects their ability to maintain lubricant within the bearing and resist external forces during handling and operation.
Innovation Solution
A seal design featuring a metal insert part with specific angular deflections at the radially outer and inner edges, where the outer deflection is shorter than the inner deflection, reducing the tendency to bow and allowing for a more compact wedge-shaped configuration that maintains sealing effectiveness while accommodating longer rolling elements, thus enhancing load-carrying capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional seal designs with equal angular deflections at outer and inner edges are used, then the seal structure is simple and easy to manufacture, but the seal bows under thermal and mechanical stresses, becoming non-round and conical, which reduces sealing effectiveness
Solution Approach 1:
The patent applies asymmetry by making the angular deflection at the radially outer edge smaller than the angular deflection at the radially inner edge. Specifically, the outer angular deflection ranges from 10° to 30° while the inner angular deflection ranges from 20° to 40°. This asymmetric design compensates for the different stress conditions and thermal expansions at different radial positions, preventing the seal from bowing and maintaining its roundness and sealing effectiveness under operational loads.
Solution Approach 2:
The patent applies local quality by differentiating the angular deflection values at different locations of the seal. The inner edge has a larger angular deflection (20°-40°) to accommodate greater thermal expansion and mechanical stress at the inner radius, while the outer edge has a smaller angular deflection (10°-30°) as it experiences different stress conditions. This location-specific optimization ensures uniform stress distribution and prevents bowing throughout the seal structure.
2Reliability
If seals with significant radial extension are used to ensure sealing effectiveness, then the seal can resist lubricant escape, but the seal occupies excessive axial space, reducing the load-carrying capacity of the bearing
Solution Approach 1:
The patent applies parameter changes by optimizing the angular deflection parameters to achieve the desired balance between sealing effectiveness and axial space occupation. By setting the outer angular deflection between 10°-30° and the inner angular deflection between 20°-40°, the seal achieves sufficient radial extension to maintain sealing effectiveness while minimizing axial protrusion. This parameter optimization allows the axial width of the seal to be reduced, thereby increasing the load-carrying capacity of the bearing without compromising sealing performance.
3Ease of manufacture
If the outer angular deflection is made equal to the inner angular deflection, then the seal structure is symmetric and easy to manufacture, but the seal becomes conical and non-round under operational stresses, reducing sealing performance
Solution Approach 1:
The patent deliberately breaks the symmetry by making the angular deflection at the outer edge (10°-30°) smaller than at the inner edge (20°-40°). This asymmetric configuration compensates for the differential thermal expansion and mechanical stress distribution across the seal's radial thickness, maintaining the seal's roundness and preventing it from becoming conical during operation, thereby preserving sealing performance.
Data Source
AI summary
A roller bearing seal includes an insert part and a polymer part connected to the insert part, and the insert part includes an annular-disc-shaped middle section having a radially inner deflection and a radially outer deflection, and a first ratio (L2/L1) of an axial length (L2) of the outer deflection to an axial length (L1) of the inner deflection is less than 0.65.