Turbofan Fan Disk Locking Mechanism for Axial Safety
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Solution Overview
Problem
Existing turbofan engine designs fail to securely prevent axial detachment of the fan in case of low-pressure shaft or fan disk breakage, requiring additional and costly mechanical connections that only address shaft breakage, not disk breakage.
Innovation Solution
Incorporating a fan safety mechanism with circumferentially spaced first and second locking portions on the fan disk and a non-rotating component, respectively, designed to interlock during axial displacement, preventing fan detachment by aligning obliquely to the axial direction, thus eliminating the need for additional mechanical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second fan shaft is added to secure the fan axially, then fan protection against shaft breakage is improved, but device complexity and weight increase
Solution Approach 1:
The locking mechanism is divided into multiple circumferentially spaced locking portions (first locking portions on the fan disk, second locking portions on the non-rotating component) that engage with each other. This segmentation allows the safety function to be distributed across multiple simple elements rather than requiring a single complex additional shaft connection.
Solution Approach 2:
The locking portions serve multiple functions: they provide axial securing of the fan during normal operation, and they automatically engage to prevent fan detachment in the event of shaft or disk breakage. This multi-functionality eliminates the need for separate shaft breakage protection mechanisms.
2Reliability
If a second fan shaft is added to secure the fan axially, then fan protection against shaft breakage is improved, but weight increases
Solution Approach 1:
The locking portions are designed as simple, lightweight structural features integrated into existing components (fan disk and non-rotating component) rather than requiring additional heavy-duty shafts or mechanical connections. These simple elements provide sufficient safety functionality without adding significant weight.
3Reliability
If locking portions are aligned obliquely to engage during axial displacement, then fan protection against disk breakage is improved, but manufacturing precision requirements increase
Solution Approach 1:
The locking portions are arranged in the circumferential direction rather than requiring precise axial alignment. The oblique alignment allows the locking portions to engage automatically when the fan disk moves axially due to breakage, converting an axial displacement problem into a circumferential engagement solution that is more tolerant of manufacturing variations.
Data Source
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AI summary
The invention relates to a turbofan drive unit comprising a fan (10) with a fan disk (12), a low-pressure shaft (81) connected to the fan disk (12), and a non-rotating component (6) arranged downstream of the fan disk (12). It is provided that a downstream section (122) of the fan disk has a plurality of first locking sections (125) spaced apart from each other in the circumferential direction, and an upstream section (65) of the non-rotating component (6) has a plurality of second locking sections (62) spaced apart from each other in the circumferential direction. The first and second locking sections (125, 62) are designed and arranged such that they are disengaged during normal operation, with the first locking sections (125) having a more downstream axial position than the second locking sections (62).In the event of a break in the low-pressure wave (81) or the fan disc (12), the first locking sections (125) engage with the second locking sections (62).