Stabilizing Ring for Backing Ring Fretting Wear
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Solution Overview
Problem
Fretting wear and corrosion issues arise between backing rings and axle fillets due to cyclic flexure and moisture ingress in railcar bearings, leading to increased wear and potential loss of clamp fit, especially when using traditional backing rings on newer axles with larger dust guard diameters.
Innovation Solution
A stabilizing ring with a rigidifying element and a compression member is introduced, featuring an axially directed leg with an interference fit around the axle section and a radially directed flange within the counterbore of the backing ring, where the compression member is made from a more flexible material than the rigidifying element, reducing movement and moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fitted backing ring with counterbore is used to receive the dust guard section, then the joint between backing ring and fillet is stiffened and moisture is excluded, but additional machining to close tolerances is required which increases manufacturing expense
Solution Approach 1:
The invention changes the dimensional parameters of the stabilizing ring and compression member to create an interference fit system that provides joint stability without requiring close-tolerance machining of the backing ring counterbore. The compression member is sized to create sufficient compressive force when installed, achieving the desired joint stiffness through parameter optimization rather than tight tolerances.
Solution Approach 2:
The stabilizing ring assembly uses composite construction with a rigid stabilizing ring and a more compliant compression member made from different materials. This combination allows the rigid ring to provide structural support while the compliant member absorbs manufacturing variations and provides the necessary compressive force, achieving reliable joint stabilization without expensive close-tolerance machining.
2Reliability
If a stabilizing ring is installed in the counterbore to rigidify the backing ring on traditional axles, then the backing ring is stabilized over the fillet, but the stabilizing ring is difficult to form in circular configuration and is expensive to manufacture
Solution Approach 1:
The stabilizing ring is divided into two separate components: a rigid stabilizing ring and a compliant compression member. This segmentation allows each component to be manufactured using simpler, more cost-effective processes. The rigid ring can be formed from sheet material through bending and forming operations, while the compression member can be manufactured from extruded or molded material, both avoiding the difficulty of forming a complete circular stabilizing ring as a single piece.
Solution Approach 2:
The compression member is made from a compliant material that can be formed into a circular or annular shape more easily than rigid materials. This flexible component can be extruded or molded into the required shape and then installed between the stabilizing ring and the dust guard section, providing the necessary compressive force without the manufacturing difficulties associated with forming rigid circular structures.
3Reliability
If the compression member is made from compliant material, then microaxial movement is permitted to reduce fretting wear, but the stabilizing effect is reduced compared to a fully rigid structure
Solution Approach 1:
The invention optimizes the parameters of the compression member including its material properties, cross-sectional area, and length to achieve the right balance between compliance and stabilizing force. By carefully selecting the compressive strength and elasticity modulus of the compression member material, sufficient microaxial movement is permitted to reduce fretting wear while maintaining adequate stabilizing force to prevent excessive backing ring movement.
Solution Approach 2:
The composite structure of the rigid stabilizing ring and compliant compression member creates a system where the rigid ring provides the primary stabilizing force and structural support, while the compliant compression member provides the necessary microaxial compliance to reduce fretting wear. The combination of these two materials with different mechanical properties achieves both stabilization and wear reduction simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The stabilizing ring effectively reduces fretting and corrosion by stabilizing the backing ring on the axle, maintaining a secure fit and minimizing wear, while allowing for microaxial movement to prevent excessive stress and maintaining a seal against moisture ingress.
Implementation Method 1
the compression member being formed from a material that is more flexible than the material from which the rigidifying element is formed
Implementation Method 2
an axially directed leg that fits over the enlarged axle section with an interference fit
Data Source
AI summary
An axle has a journal to which an antifriction bearing is fitted on an enlarged or dust guard section located beyond the journal, with a fillet leading from the journal up to the enlarged section. A backing ring fits over and against the fillet of the journal and has a counterbore that receives the adjacent end of the enlarged section. A stabilizing ring fits into the counterbore of the backing ring and around the enlarged section of the journal to stabilize the backing ring and thereby reduce radial and circumferential movement between it and the fillet of the journal. The stabilizing ring includes a rigidifying element that fits over the enlarged section of the axle with an interference fit and a more flexible compression member that lies within the counterbore where it exists in a state of compression between the counterbore and the rigidifying element. The stabilizing ring allows some microaxial movement of the backing ring.