Conical Fastening Means for Aerospace Attachment Assembly
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Solution Overview
Problem
Current fastening means and attachment assemblies in aerospace applications, such as rotor systems, face challenges with contamination due to non-smooth surfaces, leading to increased maintenance time and risk of damage, and require complex manufacturing processes with tight tolerances to prevent vibrations and misalignment.
Innovation Solution
A fastening means comprising a bolt with conical and cylindrical portions, accompanied by conical and cylindrical bushings and sleeves, ensuring smooth surface abutment and reduced parts count, which simplifies assembly and maintenance while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional fastening means with multiple parts and non-smooth surfaces are used, then structural complexity is reduced, but contamination resistance deteriorates and maintenance time increases
Solution Approach 1:
The invention merges the bolt head and bushing into a single integrated component. The bushing is formed as an extension of the bolt head, eliminating the need for separate parts. This integration creates smooth continuous surfaces that prevent particle accumulation while reducing the number of components and assembly steps.
2Manufacturing precision
If tight tolerances and co-boring processes are used to align bores, then manufacturing precision is improved, but productivity decreases and production cost increases
Solution Approach 1:
The conical bushing is pre-formed as an integral part of the bolt during manufacturing. This preliminary action ensures that the bushing's outer surface is already precisely shaped to match the bore geometry, eliminating the need for subsequent co-boring operations or master fixture alignment during assembly.
3Ease of operation
If expandable fasteners with larger bore diameters or smaller bolt core diameters are used, then ease of assembly is improved, but structural strength deteriorates
Solution Approach 1:
The invention changes the geometric parameters of the fastening interface by using a conical bushing that matches the conical bore. This parameter change allows for a precise interference fit that provides both easy assembly through the tapered guidance and high structural strength through the optimized contact surface area and stress distribution.
4Reliability
If multiple separate components are used in fastening means, then ease of manufacture is improved, but reliability deteriorates due to particle accumulation and potential damage
Solution Approach 1:
The bolt head and bushing are manufactured as a single integrated component, eliminating interfaces between parts where particles could accumulate. This merger improves reliability by removing potential failure points while the integrated design can be manufactured using standard processes without significant complexity.
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
This configuration reduces contamination, decreases maintenance time, enhances operational safety by minimizing vibrations, and allows for less expensive and efficient production without the need for master fixtures or co-boring, resulting in a stronger and more reliable attachment assembly.
Implementation Method 1
a first bushing with a conical inner surface arranged in circumferential abutment to the first bolt portion
Implementation Method 2
a nut to be threadedly engaged to the second bolt portion
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The present invention relates to a fastening means (22) and an attachment assembly (42). The fastening means (22) comprises a bolt (24) having a first bolt portion (26), a second bolt portion (28) and an intermediate bolt portion (30) arranged between the first bolt portion (26) and the second bolt portion (28). The first bolt portion (26) is conical and the second bolt portion (28) is threaded. The fastening means (22) further comprises a first bushing (34) with a conical inner surface arranged in circumferential abutment to the first bolt portion (26) and a nut (8) to be threadedly engaged to the second bolt portion (28). The attachment assembly (42) for securing objects (46, 50, 54) to each other comprises at least two bores, arranged through the objects, comprising a first bore portion (44), a second bore portion (52) and an intermediate bore portion (48), respectively. The intermediate bore portion (48) is arranged between the first bore portion (44) and the second bore portion (52). The attachment assembly also com- prises at least two fastening means (22), each of the fastening means (22) being arranged inside the bores, respectively.