Locknut Sun Gear Shaft Assembly for Axial and Radial Retention
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Solution Overview
Problem
Turbine engine shaft assemblies face excessive wear due to bi-directional axial and radial movement, leading to wear on shafts and interfacing components, necessitating a solution for bi-directional axial retention and radial retention while minimizing assembly forces.
Innovation Solution
A shaft assembly comprising a coupling shaft, a spacer with elastic material properties, a sleeve with threaded portions, and a nut, arranged to provide bi-directional axial retention and radial support, distributing forces along the spacer rather than the shaft, using a combination of a spacer with splits and a polymer matrix composite material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional shaft assemblies are used without additional retention components, then the structure is simple, but excessive wear occurs on shafts and interfacing components due to bi-directional axial and radial movement
Solution Approach 1:
The shaft assembly is segmented into multiple functional components: a shaft, a spacer with splits, a sleeve with threaded portions, and a nut. This segmentation allows each component to address specific retention needs (axial and radial) independently, reducing wear through proper force distribution while maintaining manageable structural complexity
Solution Approach 2:
The spacer acts as an intermediary component between the shaft and the sleeve/nut assembly. It mediates the retention forces by providing a compliant interface that distributes loads, preventing direct contact and wear between the shaft and retention components while enabling bi-directional axial and radial retention
2Reliability
If retention components are added to prevent excessive shaft movement, then wear resistance improves, but assembly forces on the shaft increase
Solution Approach 1:
The spacer serves as a mediator that intercepts and distributes retention forces, preventing concentrated loads on the shaft. By positioning the spacer between the shaft and the sleeve/nut assembly, it absorbs and distributes assembly forces across a larger area, reducing peak forces on the shaft while maintaining effective retention
Solution Approach 2:
The spacer's material properties and geometric parameters (such as thickness, split configuration, and elastic modulus) are optimized to achieve the desired force distribution. By adjusting these parameters, the spacer can be tuned to provide adequate retention while limiting assembly forces on the shaft to acceptable levels
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 assembly effectively minimizes assembly forces on the shaft and interfacing components, providing robust axial and radial retention, thereby reducing wear and limiting unwanted energy transfer, enhancing durability and performance under varying torque and power conditions.
Implementation Method 1
a spacer (150) defining a first portion extended inward in the radial direction R and a second portion extended in the axial direction A... the first material comprises an elastic material
Data Source
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AI summary
The present disclosure is directed to a shaft assembly (95) for a turbine engine (10), wherein the turbine engine (10) defines an axial direction and a radial direction, wherein the turbine engine (10) includes a fan or propeller assembly (14) and an engine core (20), and further wherein the fan or propeller assembly (14) includes a gearbox (45). The turbine engine (10) includes a coupling shaft (100), a spacer (150), a sleeve (200), and a nut (250) in adjacent radial arrangement. The coupling shaft (100) is connected at a first end (97) to the engine core (20) and coupled at a second end (96) to the gearbox (45). The coupling shaft (100) defines an annular surface (103) extended along the axial direction and a groove (104) extended in a circumferential direction. The spacer (150) defines a first portion (151) extended inward in the radial direction and a second portion (152) extended in the axial direction. The first portion (151) is disposed in the groove (104) of the coupling shaft (100). The sleeve (200) defines a threaded portion (202) comprising a plurality of sleeve threads (204) defined outwardly in the radial direction. The threaded portion (202) extends along the axial direction and is disposed outward of the spacer (150) in the radial direction. The nut (250) defines a plurality of nut threads (252) defined inwardly in the radial direction. The plurality of nut threads (252) of the nut (250) is configured to mate with the plurality of sleeve threads (204) of the sleeve (200). The nut (250) defines a radial portion (254) extended inward in the radial direction. The radial portion (254) is adjacent to at least a portion of the sleeve (200) and at least a portion of the spacer (150) in the axial direction.