Seal Runner Mounting with Interference Fit Stress Relief
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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 for attachment, followed by disengagement to reduce preload and internal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal runner is installed using conventional installation methods, then the seal runner can be mounted onto the rotor, but high internal stresses and preload are generated in the seal runner
Solution Approach 1:
The installation tool is designed with locating surfaces that pre-position the seal runner and rotor in the correct alignment before the interference fit is applied. The tool includes an inner locating surface and an outer locating surface that ensure proper coaxial alignment and positioning of the seal runner relative to the rotor before mounting, preventing misalignment-induced stresses
Solution Approach 2:
The installation tool acts as an intermediary device between the installer and the seal runner/rotor assembly. It controls the mounting process by providing locating surfaces that mediate the alignment and force application, ensuring that the interference fit is applied uniformly and correctly without generating excessive localized stresses
2Strength
If the runner mount is tightly fitted to the rotor through radial interference fit, then secure attachment is achieved, but axial preload increases and may cause damage
Solution Approach 1:
The installation process uses a dynamic approach where the installation tool applies axial force to press the runner mount onto the rotor, then the tool is removed allowing the seal runner to axially disengage from the rotor. This dynamic process enables the radial interference fit to provide secure attachment while avoiding permanent excessive axial preload that could damage the seal runner
Solution Approach 2:
The installation tool provides preliminary alignment and controlled force application during the interference fit process. By pre-positioning the components correctly and controlling the mounting force, the tool ensures optimal attachment strength is achieved without applying excessive axial preload that would compromise the seal runner
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 method reduces internal stresses in the seal runner, thereby extending its lifespan and ensuring a secure, stress-free assembly.
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
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AI summary
A method is provided for assembling a structure (20) of an aircraft powerplant. This method includes mounting a seal runner (32) onto a rotor (30) using an installation tool (108), the installation tool (108) including an inner locating surface (118) and an outer locating surface (120), the inner locating surface (118) axially recessed from and radially inboard of the outer locating surface (120). The mounting of the seal runner (32) includes axially pressing a runner mount (72) onto the rotor (30) by moving the installation tool (108) axially towards the rotor (30), with the outer locating surface (120) axially pressed against a distal end (68) of the seal runner (32), until the inner locating surface (118) axially engages the distal end (46) of the rotor (30). After the seal runner (32) is mounted onto the rotor (30) using the installation tool (108), the runner mount (72) is attached to the rotor (30) through a radial interference fit between the runner mount (72) and the rotor (30) and the runner mount (72) is axially disengaged from the rotor (30)°.