Differential Thread Locking Annulus for Precise Axial Preload
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Solution Overview
Problem
Existing preloading systems face challenges in achieving precise and cost-effective axial preloading with locking features, particularly in components subject to mechanical vibration, due to limitations in keyway density and thread pitch, which require expensive precision manufacturing and are prone to wear.
Innovation Solution
A system with multiple annuli having different thread pitches and keyways allows for precise axial preloading by aligning and rotating these annuli relative to a housing, enabling fine-tuning of preload values and reducing frictional wear through differential thread engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the density of keyways is increased to enable more precise preload locking, then locking resolution is improved, but manufacturing complexity and cost increase due to requiring very precisely manufactured components
Solution Approach 1:
The system divides the single keyway structure into multiple independent keyways distributed across different annuli. Each annulus has its own set of keyways, allowing the locking function to be segmented across multiple components rather than requiring high-density keyways in a single component, thus improving locking resolution without proportionally increasing manufacturing complexity of each individual part.
Solution Approach 2:
The patent employs nested annuli where an inner annulus is positioned within an outer annulus, both having keyways that can align with housing keyways. This nested configuration allows multiple levels of keyway alignment to achieve fine preload adjustment without requiring each annulus to have high-density keyways, thereby improving locking resolution while managing manufacturing complexity through the nesting arrangement.
2Measurement precision
If thread pitch is made finer to achieve more precise preload values, then measurement precision is improved, but manufacturing precision requirements increase making production difficult and expensive
Solution Approach 1:
The system segments the preload adjustment function across multiple annuli with different thread pitches. The outer annulus has a first thread pitch while the inner annulus has a second thread pitch, allowing each thread to be manufactured with standard precision tolerances rather than requiring a single fine-pitch thread to be manufactured with extremely high precision.
Solution Approach 2:
Different regions (annuli) of the system have different thread pitch characteristics optimized for their specific functions. The outer annulus and inner annulus can have different thread pitches suited to their respective roles in the preload mechanism, allowing each local region to be manufactured with appropriate precision levels rather than requiring uniform high precision throughout.
3Adaptability or versatility
If keyway density is increased to provide more locking positions, then the number of possible preload values is improved, but component wear increases due to more frequent engagement cycles
Solution Approach 1:
The locking function is segmented across multiple annuli with different numbers of keyways. The outer annulus has a first number of keyways while the inner annulus has a second number of keyways, creating a combined locking system that provides multiple preload positions without requiring any single annulus to have high keyway density, thereby reducing wear on individual keyway engagements.
Solution Approach 2:
The system allows dynamic selection of different keyway alignments between the annuli and housing to achieve various preload positions. The multiple annuli can rotate independently to align different combinations of keyways, providing adaptability for multiple preload values while distributing wear across more keyway pairs rather than concentrating it on a single high-density set.
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 system achieves higher locking resolution and increased component longevity by allowing precise preload values with reduced wear, overcoming manufacturing and operational hurdles of traditional systems.
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 and a threaded inner circumferential surface with a second 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. The inner annulus is provided with a third number of keyways disposed around its circumference.
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3C
AI summary
A system for axially preloading a component, comprising a housing (202) and a component (208) disposed radially internal to the housing (202). The housing (202) comprises a threaded inner circumferential surface (210) with a first thread pitch (P1). The system further comprises an outer annulus (224) radially inward of the housing (202), comprising 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 (234) radially inward of the outer annulus (224), comprising a threaded outer circumferential surface with a thread pitch substantially equal to the second thread pitch (P2). The housing (202) is provided with a first number (N1) of keyways disposed around its circumference. The outer annulus (224) 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 disposed around its circumference. The outer annulus (224) is configured to rotate with respect to the housing (202) to enable alignment of a keyway provided in the outer annulus (224) and a keyway in the housing (202). The inner annulus (234) is configured to rotate with respect to the outer annulus (224) to enable alignment of a keyway provided in the inner annulus (234) and a keyway in the outer annulus (224). The inner annulus (234) is configured to be translated axially towards the component (208) upon rotation of the outer annulus (224) when the inner annulus (234) and the housing (202) are rotationally locked to one another.