Differential Thread Locking Annulus for Precise Axial Preload
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Solution Overview
Problem
Existing systems for axial preloading of components, such as bearing assemblies, face limitations in precision and longevity due to the limited number of locking positions and increased manufacturing complexity when trying to enhance keyway density or thread pitch, leading to premature wear and high production costs.
Innovation Solution
A system comprising multiple annuli with different thread pitches and keyways allows for precise axial preloading by aligning and rotating these components to achieve a higher locking resolution, with the inner and outer annuli translating axially to apply preload without rotating against the component, thereby reducing friction and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the density of keyways is increased to enable more precise preload locking, then the locking resolution is improved, but the manufacturing complexity and cost increase due to the need for very precisely manufactured components
Solution Approach 1:
The system divides the single keyway alignment function into multiple independent keyway systems: an outer annulus with first keyways engaging with the housing, and an inner annulus with second keyways engaging with the outer annulus. This segmentation allows each keyway set to operate independently with lower precision requirements, while collectively achieving high locking resolution through their combined action.
Solution Approach 2:
The invention introduces a radial dimension to the keyway alignment system by implementing keyways at different radial positions (outer annulus and inner annulus). Instead of increasing keyway density in a single plane, the system uses multiple radial layers of keyways, transforming a two-dimensional problem into a three-dimensional solution that achieves higher precision without proportionally increasing manufacturing complexity.
2Manufacturing precision
If the thread pitch is made finer to achieve more precise axial preloading, then the preload precision is improved, but the manufacturing difficulty and cost increase
Solution Approach 1:
The threading system is segmented into multiple independent threading interfaces: outer threading between the housing and outer annulus, and inner threading between the outer annulus and inner annulus. Each threading interface can be manufactured with standard pitch values, avoiding the need for a single extremely fine pitch thread, thereby reducing manufacturing difficulty while maintaining overall precision.
Solution Approach 2:
The system employs nested threading where the outer annulus contains both outer threading (engaging the housing) and inner threading (engaging the inner annulus). This nested configuration allows each threading interface to operate at its own optimal pitch, with the combined effect achieving high precision preload without requiring any single thread to be excessively fine.
3Device complexity
If a single annulus is used for axial preloading, then the device complexity is reduced, but the achievable locking resolution and precision are limited
Solution Approach 1:
The single annulus is segmented into two independent annular components: an outer annulus and an inner annulus. Each annulus has its own set of keyways and threading interfaces, allowing them to function as independent positioning systems. This segmentation doubles the number of available locking positions without requiring a single overly complex component.
Solution Approach 2:
The system merges two independent annular positioning systems (outer and inner annuli) into a unified preload mechanism. The outer annulus provides coarse positioning through its keyways with the housing, while the inner annulus provides fine positioning through its keyways with the outer annulus. This combination achieves high locking resolution while keeping individual components relatively simple.
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
This approach enhances the achievable precision and locking resolution of the preload, increasing the longevity of components by minimizing friction and manufacturing challenges, while maintaining cost-effectiveness.
Implementation Method 1
The housing comprises a threaded inner circumferential surface with a first thread pitch. The outer annulus comprises a threaded outer circumferential surface with a thread pitch substantially equal to the first thread pitch
Implementation Method 2
The housing is provided with a first number of keyways disposed around its circumference. The outer annulus is provided with a second number of keyways disposed around its circumference
Implementation Method 3
The inner annulus is configured to be translated axially towards the component upon rotation of the outer annulus when the inner annulus and the housing are rotationally locked to one another
Data Source
AI summary
A system for axially preloading a component includes: a housing and a component disposed radially internal to the housing. The housing includes a threaded inner circumferential surface with a first thread pitch (P1). The system further includes an outer annulus radially inward of the housing that a threaded outer circumferential surface with a thread pitch substantially equal to the first thread pitch (P1) and a threaded inner circumferential surface with a second thread pitch (P2) and an inner annulus radially inward of the outer annulus, that includes a threaded outer circumferential surface with a thread pitch substantially equal to the second thread pitch (P2). The housing is provided with a first number (N1) of keyways disposed around its circumference. The outer annulus is provided with a second number (N2) of keyways disposed around its circumference. The inner annulus is provided with a third number (N3) of keyways around its circumference.