Seal Runner Mounting on Aircraft Rotor With Reduced Preload
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Solution Overview
Problem
Existing methods for installing seal runners in aircraft powerplants are in need of improvement to enhance efficiency and reduce internal stresses.
Innovation Solution
A method involving the use of an installation tool with inner and outer locating surfaces to axially press a seal runner onto a rotor, utilizing a radial interference fit and ensuring the runner mount is axially disengaged from the rotor, reducing preload and internal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional installation methods are used to install seal runners, then the seal runner can be installed onto the rotor, but high internal stresses and preload are generated in the runner mount
Solution Approach 1:
The installation tool is designed with locating surfaces that pre-position the seal runner at the correct location and orientation before the pressing operation begins. The outer locating surface engages the distal end of the seal runner and the inner locating surface engages the distal end of the rotor, ensuring proper alignment and preventing misalignment stresses before the axial pressing force is applied.
Solution Approach 2:
The installation tool acts as an intermediary device between the pressing force and the seal runner. It distributes the axial pressing force uniformly through its locating surfaces and guides the seal runner onto the rotor, preventing concentrated loading and reducing internal stresses in the runner mount during installation.
2Reliability
If the runner mount is pressed axially onto the rotor, then the seal runner can be mounted, but the runner mount remains axially engaged creating preload
Solution Approach 1:
The mounting process is segmented into two distinct phases: first, the radial interference fit is established by axial pressing to secure the seal runner to the rotor; second, the runner mount is axially disengaged from the rotor by a specific amount (0.002-0.006 inches) to relieve preload while maintaining the radial attachment. This segmentation allows both secure mounting and reduced stress.
Solution Approach 2:
The axial position parameter of the runner mount is changed after the radial interference fit is established. The runner mount is pressed axially onto the rotor to create the interference fit, then deliberately repositioned axially by disengaging it from the rotor distal end by a controlled amount, changing the axial parameter to reduce preload while maintaining radial attachment.
3Manufacturing precision
If precise alignment and positioning are achieved during installation, then installation accuracy is improved, but the installation process becomes more complex
Solution Approach 1:
Multiple alignment and positioning functions are merged into a single installation tool structure. The outer locating surface provides radial positioning and axial stopping, while the inner locating surface provides rotational alignment and axial engagement with the rotor. Both locating surfaces work simultaneously to achieve precise alignment in one operation, eliminating the need for separate alignment steps or multiple tools.
Solution Approach 2:
The installation tool is designed with multi-functionality to perform alignment, positioning, and pressing operations simultaneously. The locating surfaces serve multiple purposes: the outer locating surface both radially positions and axially stops the seal runner, while the inner locating surface both rotationally aligns and axially engages with the rotor, reducing the need for separate specialized tools.
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 method facilitates efficient assembly of seal runners with reduced internal stresses, enhancing the lifespan and performance of aircraft powerplant components.
Implementation Method 1
the runner mount is attached to the rotor through a radial interference fit between the runner mount and the rotor
Data Source
AI summary
A method is provided for assembling a structure of an aircraft powerplant. This method includes mounting a seal runner onto a rotor using an installation tool, the installation tool including an inner locating surface and an outer locating surface, the inner locating surface axially recessed from and radially inboard of the outer locating surface. The mounting of the seal runner includes axially pressing a runner mount onto the rotor by moving the installation tool axially towards the rotor, with the outer locating surface axially pressed against a distal end of the seal runner, until the inner locating surface axially engages the distal end of the rotor. After the seal runner is mounted onto the rotor using the installation tool, the runner mount is attached to the rotor through a radial interference fit between the runner mount and the rotor and the runner mount is axially disengaged from the rotor.