Grooved Deformable Sleeve Bolted Joint for Zero-Clearance Fit
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Solution Overview
Problem
Bolted joints fail to maintain a zero-clearance fit and prevent slippage under high shear loads due to insufficient friction, particularly in applications with misalignment issues between the clamped component and the bolt receiving member.
Innovation Solution
A bolted joint design featuring a deformable sleeve with grooves or flutes on its interior surface, which reduces friction and radial loads during installation, allowing for misalignment accommodation and reduced material strength requirements in the clamped and bolt receiving members, while maintaining a zero-clearance fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a deformable sleeve is used to provide a zero-clearance fit, then misalignment accommodation is improved, but friction between the sleeve and through holes is insufficient to prevent slippage under high shear loads
Solution Approach 1:
The sleeve is segmented with longitudinal grooves or flutes that divide the continuous cylindrical surface into sections. This segmentation reduces the contact area between the sleeve and the through hole walls, lowering friction during installation while maintaining sufficient friction for slippage prevention under load. The grooves allow the sleeve to deform more easily during installation while still providing adequate gripping force when tightened.
Solution Approach 2:
The sleeve has non-uniform surface properties due to the grooves or flutes, creating areas of different friction characteristics. The grooved regions have reduced friction to facilitate installation and misalignment accommodation, while the raised portions or lands between grooves maintain contact and provide friction for slippage prevention. This local variation in surface quality allows the sleeve to simultaneously accommodate misalignment and prevent slippage.
2Reliability
If conventional sleeves without grooves are used, then friction is sufficient to prevent slippage, but radial loads and axial loads are too high, limiting material and geometry options
Solution Approach 1:
By segmenting the sleeve surface with grooves, the contact area is reduced, which reduces the radial loads and axial loads during installation. This allows the use of lower-strength materials and thinner-walled geometries for both the clamped component and bolt receiving member, expanding design options while still maintaining sufficient friction for slippage prevention through the remaining contact areas.
Solution Approach 2:
The grooves change the physical parameters of the sleeve, specifically reducing the contact area and modifying the deformation characteristics. This parameter change reduces the installation loads (radial and axial) while maintaining the friction necessary for slippage prevention, enabling the use of materials with lower strength properties and geometries with thinner walls.
3Manufacturing precision
If matching circular patterns of through holes are used, then zero-clearance fit is achieved, but hole position tolerance capability is poor
Solution Approach 1:
The sleeve is designed to be deformable rather than rigid, allowing it to dynamically adjust to misalignments between the through hole and counterbore. During installation, the sleeve deforms to accommodate position errors, and when tightened by the bolt, it maintains a zero-clearance fit between the clamped component and bolt receiving member. This dynamic adaptation enables tolerance of hole position variations while achieving the desired fit.
Solution Approach 2:
The sleeve's deformable parameter allows it to change shape during installation to accommodate misalignments. The grooves further modify the deformation characteristics, enabling the sleeve to flex and adapt to position errors while still providing a tight fit when installed. This parameter change from rigid to deformable allows tolerance of manufacturing variations.
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 effectively minimizes slippage and accommodates misalignment, enabling the use of lower-strength materials and smaller bolt sizes, while maintaining the integrity of the joint under service loads, thus enhancing the reliability and versatility of bolted joints in high shear load applications.
Implementation Method 1
Each of the deformable sleeves includes at least one groove or flute on a sleeve interior surface that results in less friction between both the bolt and the sleeve, which reduces the radial load necessary to deform the sleeve during the installation process
Implementation Method 2
a bolt having a shoulder to cold form a deformable sleeve in order to provide a 'zero-clearance' fit
Implementation Method 3
tapered shoulders on the bolts dilate deformable sleeves until the outer diameters of the sleeves contact internal walls of through holes in the clamped component
Data Source
Figure 1a~1b
Figure 2a~2c
Figure 3a~3c
AI summary
A bolted joint providing a "zero-clearance" fit formed from a bolt including a shoulder that works during installation to cold form a deformable sleeve. The bolted joint joins a bolt receiving member to a clamped component. One or more bolted joints may be used and as the bolts are installed, shoulders on each of the bolts dilate deformable sleeves until the outer diameters of the sleeves contact internal walls of through holes in the clamped component. Each of the deformable sleeves includes at least one groove or flute on its interior surface that results in: reduced radial load on internal walls of the clamped component and the bolt receiving members, and less friction between the sleeve and both the clamped component and a counter bore disposed within the bolt receiving member, thereby allowing for smaller percentage of the bolt's tensile strength capability required to deform the sleeve.