Segmented Spacer Ring for Jet Engine Center Bent Tube
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Solution Overview
Problem
In jet engines, the thermal deformation differences between the center bent tube and the shaft cause local stress and positional inaccuracies due to the use of resin spacer rings with high friction and wear issues, leading to difficulties in attachment and centering of the center bent tube.
Innovation Solution
A spacer ring with a cut portion, chamfered ends, and a high elastic modulus material like polytetrafluoroethylene is used, allowing for easy attachment and preventing wear, while its shape ensures uniform contact and reduced deformation, facilitating accurate centering of the center bent tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous ring-shaped spacer ring is used to support the center bent tube, then the centering function is provided, but the spacer ring is caught by the support portion during insertion and is easily worn due to high friction
Solution Approach 1:
The spacer ring is divided into multiple arc-shaped segments separated by gaps rather than being a continuous ring. This segmentation allows the segments to be compressed and inserted between the support portion and center bent tube without being caught, while still providing effective centering support when assembled.
2Ease of manufacture
If a resin material with small elastic modulus is used for the spacer ring, then the spacer ring can be attached to the center bent tube, but the material has high friction coefficient and is easily worn
Solution Approach 1:
The elastic modulus parameter of the spacer ring material is increased by selecting materials with higher stiffness. This change allows the spacer ring to maintain its shape and provide stable centering support while reducing compression deformation, thereby improving wear resistance and reducing friction during operation.
3Ease of manufacture
If the cross section of the spacer ring is circular, then the spacer ring can be formed simply, but the spacer ring is greatly deformed and not uniform in the circumferential direction
Solution Approach 1:
The spacer ring cross section is changed from a circular shape to an asymmetric shape with different dimensions in the radial and axial directions. This asymmetric design, combined with the segmented structure, prevents uniform circumferential deformation while maintaining manufacturability through standard molding or machining processes.
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 solution enables easy attachment and accurate centering of the center bent tube by preventing wear and ensuring uniform deformation, reducing vibrations and stress, thus improving the operational stability of the jet engine.
Implementation Method 1
the spacer ring can slide on the support portion, it is possible to absorb the difference between thermal deformation amounts or the like of the shaft and the center bent tube
Implementation Method 2
this material has a high friction coefficient and is easily worn
Data Source
AI summary
A jet engine, which includes a hollow shaft, a center bent tube which is inserted into the shaft, an annular support portion which protrudes from an inner wall surface of the shaft, and an annular spacer ring which is provided on an outer wall surface of the center bent tube and slidably abuts on the support portion, is provided. The spacer ring includes an outer circumferential surface which has a shape along a surface of the support portion in an axial direction of the shaft, an inner circumferential surface which has a shape along the outer wall surface of the center bent tube in the axial direction of the shaft, and a cut portion in which a portion of the spacer ring is cut.