Deformable Counterbore Protection Dish for Interference-Free Mounting
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Solution Overview
Problem
The existing protection dishes for counterbores in aircraft mechanical parts, particularly in turbomachine directing blades, face challenges due to interference with anticorrosion treatments and paint when shrink-fitted, leading to potential damage and requiring complex tooling for installation, which can result in tool marks and additional treatment needs.
Innovation Solution
A deformable protection dish with a U-shaped axial section and a cylindrical rim that expands axially under stress, allowing for initial clearance fit into the counterbore and subsequent tight fit retention, featuring slits and a material that enables elastic or plastic deformation to accommodate the counterbore dimensions, ensuring secure mounting without damaging the surrounding components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protection dish is mounted using shrink fitting to prevent rotation and ensure secure retention, then the dish provides reliable protection and retention, but the high contact pressure damages the anticorrosion treatment and paint on the light alloy part
Solution Approach 1:
The invention changes the dimensional parameter of the dish's annular wall, making it deformable under axial stress. The wall transitions from a smaller diameter (for clearance fit) to a larger diameter (for tight fit) when subjected to axial stress from the screw head, allowing secure retention without damaging the part surface
Solution Approach 2:
The annular wall of the protection dish is designed to be dynamically deformable rather than rigid. When axial stress is applied during screw tightening, the wall expands radially to engage tightly with the counterbore, providing retention while avoiding the high contact pressures of conventional shrink fitting
2Reliability
If the protection dish is mounted using shrink fitting to ensure secure retention, then the dish prevents rotation and escape, but complex tooling is required for installation which can cause tool marks and additional treatment needs
Solution Approach 1:
The protection dish is designed to be self-installing through the deformation mechanism. The deformable annular wall automatically expands to the tight fit dimension when axial stress is applied during normal screw tightening, eliminating the need for separate installation tools or complex tooling procedures
Solution Approach 2:
The dish is pre-configured with a deformable annular wall that is designed to expand under axial stress. This preliminary design allows the dish to transition from clearance fit to tight fit automatically during the screw tightening process, without requiring pre-installation tooling
3Ease of operation
If the diameter of the annular wall is reduced to allow clearance fit for easy installation, then the mounting process is simplified and interference is avoided, but the dish cannot be securely retained in the counterbore
Solution Approach 1:
The annular wall is designed with dynamic deformability, allowing it to transition between two diameter states: a smaller diameter for clearance fit during installation, and a larger diameter for tight fit during operation, achieving both ease of mounting and secure retention
Solution Approach 2:
The invention utilizes parameter change in the diameter of the annular wall through deformation. The wall diameter changes from an initial smaller value (enabling clearance fit) to a final larger value (providing tight fit) when subjected to axial stress, resolving the contradiction between ease of installation and secure retention
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 deformable protection dish simplifies the mounting process, prevents damage to anticorrosion treatments and paint, and facilitates easier installation of turbomachine directing blades by allowing for a frictionless introduction and secure retention within the counterbore, reducing the need for complex tooling and additional treatments.
Implementation Method 1
the substantially annular wall being deformed from an initial state associated with the first state of the dish, wherein the substantially annular wall has the first transverse dimension E, to a final state, associated with the second state of the dish, wherein the substantially annular wall has the second transverse dimension E′
Implementation Method 2
the material is configured such that the substantially annular wall plastically deforms itself in response to the axial stress of determined intensity
Data Source
AI summary
The invention relates to a protection dish (32) for a counterbore formed in an aircraft mechanical part, said protection dish (32) having an axial cross-section about an axis (A) having substantially the shape of a U, and comprising a substantially annular wall (34) of axis (A) and a substantially cylindrical rim (36) of axis (A) connected to an outer periphery of said substantially annular wall (34). The invention is characterised in that said dish (32) is configured to be deformed in response to an axial stress (F) of a determined intensity applied on the substantially annular wall (34) thereof from a first state, wherein the substantially cylindrical rim (36) has a first transverse dimension (E) relative to axis (A), to a second state, wherein the substantially annular wall (34) being deformed, the cylindrical rim (36) has a second transverse dimension (E′) relative to the axis (A) that is greater than the first transverse dimension (E) along a transverse direction (T) determined relative to axis (A).