Radial Fit Bolt Assembly With Lower Tightening Load
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Solution Overview
Problem
Conventional radial fit bolts require high loads to tighten, which can exceed the load limit of the threaded heads, making installation impossible in applications with reduced clearance.
Innovation Solution
A radial fit bolt assembly with a bolt and sleeve design featuring increasing outer and inner diameters, respectively, and an annular gap and groove configuration that reduces the required load for tightening and facilitates easy installation and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional radial fit bolts are used to tighten inside the sleeve, then the bolt provides secure fastening, but the required load exceeds the load limit of the threaded heads in reduced clearance applications
Solution Approach 1:
The bolt is segmented into three axial sections (first, intermediate, and second sections) with different outer diameters. The first and second sections have larger outer diameters for radial contact with the sleeve to provide fastening strength, while the intermediate section has a smaller outer diameter that fits within the sleeve's intermediate section, reducing the tightening load requirement on the threaded heads.
Solution Approach 2:
Different sections of the bolt have different local properties: the first and second sections are designed with larger diameters to engage radially with the sleeve for strength, while the intermediate section is designed with a smaller diameter to reduce the load required for tightening. This local differentiation allows the bolt to achieve both strong fastening and reduced tightening requirements.
2Strength
If the bolt is tightly fitted inside the sleeve for secure fastening, then the connection is strong, but the bolt becomes difficult to remove and may seize
Solution Approach 1:
The segmented design allows the intermediate section of the bolt to be pulled through the intermediate section of the sleeve during removal, creating clearance that prevents seizing. The first and second sections remain radially engaged with the sleeve for strength, while the intermediate section provides a clearance path for easy removal.
Solution Approach 2:
The intermediate section of the bolt acts as an intermediary element during removal. Its smaller diameter allows it to move freely through the intermediate section of the sleeve, facilitating the extraction of the entire bolt assembly without seizing the tightly fitted first and second sections.
3Stability of the object's composition
If the bolt and sleeve are tightly fitted together, then vibration is reduced, but installation becomes difficult and requires high loads
Solution Approach 1:
The segmented bolt design enables radial contact between the first and second sections and the sleeve for vibration resistance, while the intermediate section with smaller diameter reduces installation load requirements. This segmentation allows simultaneous achievement of vibration resistance and ease of installation.
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 design allows for fast and trouble-free installation and removal of bolts, reduces the risk of seized bolts, and addresses vibration issues, while minimizing the need for frequent bolt replacement and hole preparation.
Implementation Method 1
the annular groove enables the intermediate section of the sleeve to move radially outward while tightening the bolt inside the sleeve and radially inward while removing the bolt from the sleeve
Implementation Method 2
The radial force exerted by the bolt onto the sleeve when the bolt is tightened into the sleeve is transmitted radially from the first section of the bolt to the first section of the sleeve and from the second section of the bolt to the second section of the sleeve
Data Source
AI summary
A radial fit bolt assembly includes a bolt having first and second sections with increasing diameter along a first direction, and an intermediate section axially interposed between the first and second sections. A sleeve radially surrounds the bolt and includes first and second sections with increasing inner diameter along the first direction, and an intermediate section axially interposed between the sleeve first and second sections. The first and second sections of the bolt are in radial contact respectively with the first and second sections of the sleeve, an annular gap is defined radially between the outer surface of the intermediate section of the bolt and the inner surface of the intermediate section of the sleeve, and an annular groove is provided on the outer surface of the intermediate section of the sleeve.