Aircraft Engine Bore Centering Tool with Radial Spiral Spring
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Solution Overview
Problem
Existing centering tools for aircraft engine mounts are limited in their ability to center bores with different diameters and provide precise alignment, as they rely on fixed diameters or expandable mechanisms that cannot accommodate varying bore sizes effectively.
Innovation Solution
A centering tool equipped with a hollow cylindrical body, bearing surfaces, and a spiral spring that expands radially to achieve concentric alignment over a significant range, maintaining contact over the entire periphery of the bore, allowing for precise centering of bores with different diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed diameter centering tool is used, then the tool structure is simple, but it cannot accommodate bores with different diameters
Solution Approach 1:
The centering tool employs a dynamic expansion mechanism where the cylindrical body can radially expand from a retracted state to an expanded state. This dynamic adjustment allows the tool to adapt to different bore diameters while maintaining a relatively simple overall structure, resolving the contradiction between adaptability and structural complexity.
Solution Approach 2:
The tool changes its critical parameter - the outer diameter of the cylindrical body - by transitioning between retracted and expanded states. This parameter change enables the same tool to accommodate multiple bore sizes without requiring multiple different tools, thus improving versatility without proportionally increasing complexity.
2Adaptability or versatility
If a split ring with radial expander is used, then the tool can accommodate different bore sizes, but the expansion range is limited to less than 2 mm
Solution Approach 1:
The invention uses a spherical expansion element that expands radially in all directions simultaneously. This spherical geometry provides superior concentricity compared to the linear expansion of split rings, achieving an expansion range greater than 2 mm while maintaining high centering precision through the inherent geometric advantage of spherical expansion.
3Manufacturing precision
If a split ring is used, then the tool can be introduced into non-coaxial bores, but contact is not maintained over the entire periphery
Solution Approach 1:
The tool utilizes a phase transition in its functional state - transitioning from a retracted state where the cylindrical body is compact and can be easily introduced into non-coaxial bores, to an expanded state where it maintains full peripheral contact for precise centering. This state transition allows the tool to sequentially achieve both easy introduction and precise contact without requiring complex structural modifications.
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 tool enables precise coaxial alignment of bores with different diameters, providing a more extensive expansion range than traditional split rings and ensuring accurate mounting of connecting pins, enhancing the assembly process of aircraft engine mounts.
Implementation Method 1
a spiral spring (56), surrounding the section (50) between the first and second bearing surfaces (48.1, 48.2), configured to cooperate with the bore (40) to be centered in operation. The spiral spring (56) is configured to occupy a resting, unexpanded state visible on the Figures 7A, 8A and 9A in which it has an initial outside diameter Di, and an expanded state, visible on the figure 7B, 8B and 9B in which it has an expanded outside diameter De
Data Source
Figure 1~4
Figure 5~8A
Figure 8B~9B
AI summary
The invention relates to a bore centering tool, comprising: - at least one first bearing surface (48.1) configured to be inserted into a first bore (42.1), - a spiral spring (56) configured to be positioned in a bore to be centered (40), and to occupy a rest, unexpanded state, and an expanded state in which it has an expanded outer diameter (De) greater than the inner diameter of the bore to be centered, - a radial expansion mechanism (58) configured to occupy an inactive state in which it does not act on the spiral spring (56) and an activated state in which it causes an increase in the diameter of the spiral spring (56). The invention also relates to a method for centering the bores of an aircraft engine mount using said centering tool.