Locknut Sun Gear Structure for Low-Force Bi-Directional Retention
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Solution Overview
Problem
Turbine engine shaft assemblies face excessive wear due to unidirectional axial and radial movement, leading to wear on shafts and interfacing components, necessitating a solution for bi-directional axial 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, where the spacer's split design and elastic material distribute forces, allowing for retention of the sleeve with minimal force applied to the shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shaft assembly uses traditional unidirectional retention arrangements, then the structure is simple, but excessive wear occurs on the shaft and interfacing components due to uncontrolled axial and radial movement
Solution Approach 1:
The shaft assembly is segmented into multiple functional components: a shaft, a spacer with split design, a sleeve, and a nut. The spacer is further segmented into a first portion extending radially inward and a second portion extending axially, with the first portion disposed in a groove on the shaft. This segmentation allows each component to perform specific functions for controlling movement in different directions, thereby reducing wear while maintaining structural manageability.
Solution Approach 2:
The spacer acts as an intermediary element between the shaft and the sleeve-nut assembly. The first portion of the spacer positioned in the groove provides radial retention, while the second portion provides axial retention. This intermediary structure distributes and controls movement forces, preventing excessive wear on the shaft and interfacing components while maintaining assembly integrity.
2Reliability
If bi-directional axial and radial retention is implemented, then wear on shaft and components is reduced, but assembly forces increase
Solution Approach 1:
The spacer incorporates an elastic material that provides flexible retention capabilities. The elastic material allows the spacer to deform elastically under assembly forces, accommodating the bi-directional retention requirements without generating excessive assembly forces. This flexibility enables the spacer to adapt to slight variations in component dimensions while maintaining effective radial and axial retention.
Solution Approach 2:
The elastic material properties of the spacer are utilized to change the mechanical parameters of the assembly. The elasticity allows the spacer to absorb and distribute assembly forces, reducing peak forces during assembly while maintaining the bi-directional retention function. This parameter change from rigid to elastic behavior resolves the contradiction between wear reduction and assembly force reduction.
3Reliability
If the spacer uses elastic material with split design, then forces are distributed and retention is improved, but manufacturing complexity increases
Solution Approach 1:
The split design of the spacer divides the elastic component into separable sections, which can be manufactured independently and then assembled. This segmentation simplifies the manufacturing process by allowing each segment to be formed separately using standard elastic material forming techniques, then joined to create the complete spacer with the required split configuration for force distribution.
Solution Approach 2:
The spacer utilizes elastic material that can be manufactured as a composite structure with the split design. The elastic material properties combined with the split geometry create a component that distributes forces effectively while remaining manufacturable through conventional elastic material processing methods, balancing retention capability with ease of manufacture.
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 limits unwanted movement and energy transfer between the engine core and fan or propeller assembly, reducing wear and maintaining stability under torque fluctuations and external impacts.
Implementation Method 1
The spacer defines a first material, wherein the first material comprises an elastic material
Data Source
AI summary
A turbine engine defines an axial direction and a radial direction and includes a shaft assembly, a fan or propeller assembly, an engine core, a coupling shaft, a spacer, a sleeve, and a nut The coupling shaft defines an annular surface extended along the axial direction and a groove extended in a circumferential direction. The spacer defines a first portion disposed in the groove of the coupling shaft. The sleeve defines a threaded portion that extends along the axial direction and is disposed outward of the spacer in the radial direction. The nut defines a plurality of nut threads configured to mate with the plurality of sleeve threads of the sleeve. The nut defines a radial portion adjacent to at least a portion of the sleeve and at least a portion of the spacer in the axial direction.