Dual-Material Bearing Ring for Hard Contact and Tough Fastening
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Solution Overview
Problem
Current rolling-element bearings for aircraft engines face challenges in achieving a balance between contact hardness for effective raceway performance and structural fatigue strength for reliable fastening, with case-hardened M50NiL steel being costly and having low hardness, and using lightweight materials increasing mass for equivalent fatigue performance.
Innovation Solution
A ring with a one-piece construction, where the contact portion is made of a harder material and the fastening portion of a tougher material, both formed through sintering of metallic powders, optimizing geometry for improved reliability and reducing manufacturing costs by eliminating weld beads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If case-hardening is applied to M50NiL steel ring, then contact portion hardness is improved, but manufacturing cost increases and overall hardness remains relatively low
Solution Approach 1:
The ring is constructed with two distinct materials: a harder material for the contact portion and a tougher material for the fastening portion. This local differentiation allows each portion to have optimized properties for its specific function, eliminating the need for case-hardening treatment and reducing manufacturing costs.
Solution Approach 2:
The invention uses composite construction with two different metallic materials joined together. The contact portion uses a harder material while the fastening portion uses a tougher material, creating a composite structure that achieves both hardness and toughness requirements without additional surface treatment processes.
2Strength
If M50NiL steel is used for the ring, then contact fatigue strength is improved, but fastening portion mass increases for equivalent fatigue performance
Solution Approach 1:
The fastening portion is made from a tougher material that provides adequate structural fatigue strength with reduced mass compared to using M50NiL steel throughout. This local material optimization reduces the mass of the fastening portion while maintaining required fatigue performance.
Solution Approach 2:
By combining M50NiL steel (or harder material) for the contact portion with a tougher, lighter material for the fastening portion, the composite structure achieves both contact fatigue strength and reduced fastening portion mass for equivalent structural fatigue performance.
3Reliability
If the ring is made as a one-piece construction, then manufacturing reliability is improved by eliminating weld beads, but material selection becomes more constrained
Solution Approach 1:
The one-piece construction incorporates two different metallic materials that are joined during the forming process itself, eliminating the need for separate welding operations. This composite approach maintains manufacturing reliability while enabling differentiation between contact and fastening portion materials.
Solution Approach 2:
The formation of two different materials into a single integrated piece during the same forming process merges the advantages of material differentiation with the reliability of one-piece construction, avoiding weld beads while maintaining material versatility.
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 solution enhances contact fatigue strength and structural fatigue strength, allowing for a more lightweight and reliable ring design with reduced manufacturing costs, while avoiding the limitations of case-hardening and excessive mass associated with previous solutions.
Implementation Method 1
the contact portion and the fastening portion being made in one piece
Data Source
AI summary
A ring for a connection element includes a contact portion intended to cooperate with a contact surface of another ring and a fastening portion intended to be secured to a support. The contact portion is made of a first metallic material and the fastening portion is made of a second metallic material, the hardness of the first material being substantially greater than that of the second material, and the toughness of the second material being substantially greater than that of the first material, the contact portion and the fastening portion being of one piece construction.