Clamped Bearing Raceway Sleeve for Corrosion-Resistant Masts
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Solution Overview
Problem
Conventional rotor aircraft masts made of surface-hardened steel are prone to corrosion, and while corrosion-resistant materials like PH 13-8Mo or Titanium avoid corrosive wear, they cannot be suitably surface hardened for use as integral bearing races, leading to insufficient bearing performance.
Innovation Solution
A tubular sleeve bearing raceway with a hardened outer surface and axially linear inner surface, combined with a clamp section featuring non-linear internal threads and engagement profiles, is secured to the mast using a nut to apply clamping force without stress-concentrating features like threads or retaining ring grooves, ensuring axial stability and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If surface-hardened steel is used for the mast, then bearing performance is improved, but corrosion resistance deteriorates
Solution Approach 1:
The invention divides the mast structure into two separate components: a corrosion-resistant mast body and a surface-hardened bearing raceway. This segmentation allows each component to have optimized properties for its specific function, resolving the contradiction between bearing performance and corrosion resistance.
Solution Approach 2:
The invention uses composite construction by combining a corrosion-resistant material (such as PH 13-8Mo or titanium) for the mast with a surface-hardened raceway layer. This composite approach enables the mast to simultaneously achieve corrosion resistance from the base material and bearing performance from the hardened surface layer.
2Object-affected harmful factors
If corrosion-resistant steel is used for the mast, then corrosion resistance is improved, but surface hardening capability deteriorates
Solution Approach 1:
The invention separates the mast into a corrosion-resistant base structure and a surface-hardened bearing raceway component. This segmentation allows the use of corrosion-resistant materials like PH 13-8Mo or titanium for the mast body while applying surface hardening only to the bearing raceway where it is needed, thus maintaining corrosion resistance while achieving the required bearing surface hardness.
Solution Approach 2:
The invention applies surface hardening only to the specific region where bearing contact occurs (the raceway), rather than the entire mast. This local quality approach allows the mast to be made of corrosion-resistant material that cannot be uniformly hardened, while still achieving the necessary hardness in the critical bearing area through selective surface treatment or overlay.
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 provides a corrosion-resistant, surface-hardened bearing raceway that effectively secures to the mast without adding stress-concentrating features, preventing axial movement and excessive wear, thus addressing the corrosion issues while maintaining performance.
Implementation Method 1
The surface hardened steel can be used as an integral bearing race
Implementation Method 2
the first threads are configured to mate with second threads on a nut to clamp the tubular sleeve to the shaft
Implementation Method 3
preventing axial movement and excessive wear
Data Source
AI summary
A bearing raceway for a shaft includes a tubular sleeve comprising a raceway section and a clamp section, the raceway section having a hardened outer surface and a first, axially linear, inner surface, and the clamp section having first threads and a second, axially non-linear, inner surface, where the first threads are configured to mate with second threads on a nut to clamp the tubular sleeve to the shaft.