Cylindrical Sleeve With Spring Elements For Captive Fixation
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Solution Overview
Problem
Existing assembly units face issues with securely fixing a stronger metallic sleeve within a plastics material assembly part due to production-related tolerances, leading to potential bursting or inability to press-fit, especially when using materials like aluminum or magnesium alloys.
Innovation Solution
Incorporating a cylindrical sleeve with spring elements protruding from its external face, which elastically deform inward upon insertion to securely lock within the assembly part's through opening, allowing for adjustable force locking independent of sleeve thickness and material, and accommodating non-cylindrical through openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic sleeve with defined oversize is press-fitted into the through opening, then the sleeve is securely fixed in the through opening, but production-related cumulative tolerances may cause significant surpassing of the predefined oversize leading to bursting of the through opening or assembly part
Solution Approach 1:
The patent changes the geometric parameters of the sleeve by providing spring elements that protrude by an excess length from the external face. This allows the sleeve to elastically deform during insertion, adapting to tolerance variations in the through opening while maintaining secure fixation without bursting the assembly part.
Solution Approach 2:
The patent introduces dynamic elements (spring elements) to the otherwise static sleeve structure. The spring elements can elastically deform during the insertion process, allowing the sleeve to adapt to varying through opening dimensions caused by production tolerances, and then return to their original position to provide secure fixation.
2Reliability
If a metallic sleeve with defined oversize is press-fitted into the through opening, then the sleeve is securely fixed in the through opening, but the resilience of materials like aluminum or magnesium alloys is only minor making press-fitting impossible when oversize is surpassed
Solution Approach 1:
The patent changes the geometric parameters of the sleeve by providing spring elements that protrude by an excess length from the external face. This allows the sleeve to elastically deform during insertion, adapting to tolerance variations in the through opening while maintaining secure fixation without bursting the assembly part.
Solution Approach 2:
The patent introduces dynamic elements (spring elements) to the otherwise static sleeve structure. The spring elements can elastically deform during the insertion process, allowing the sleeve to adapt to varying through opening dimensions caused by production tolerances, and then return to their original position to provide secure fixation.
3Object-affected harmful factors
If spring elements with excess length are provided on the sleeve, then the sleeve can be inserted without bursting the through opening, but the sleeve requires additional manufacturing steps to add spring elements
Solution Approach 1:
The patent segments the sleeve structure by adding separate spring elements to the cylindrical body. This segmentation allows the spring elements to independently deform during insertion to prevent bursting, while the main sleeve body maintains its structural integrity for secure fixation.
4Force
If the excess length of spring elements is dimensioned for elastic deformation, then the spring elements can press against the wall of the through opening, but precise control of the elastic force requires careful dimensioning of the spring elements
Solution Approach 1:
The patent changes the geometric parameters of the spring elements (excess length, thickness, material properties) to achieve the desired elastic restoring force. By carefully dimensioning these parameters, the spring elements generate sufficient force to press against the through opening wall and secure the sleeve while accommodating production tolerances.
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
Ensures precise and captive fixation of the sleeve, enabling secure assembly without material bursting and allowing for flexible design adaptations, including varying spring element dimensions and configurations to suit different materials and manufacturing variations.
Implementation Method 1
the excess length is dimensioned to cause the at least one spring element to be elastically moved radially inward by contact with the wall of the through opening upon the cylindrical sleeve being introduced into the through opening, causing the at least one spring element to press against the wall of the through opening as a result of elastic restoring forces
Data Source
AI summary
An assembly unit includes an assembly part penetrated by a through opening and a cylindrical sleeve which is captively fixed in the through opening. The sleeve has at least one spring element which protrudes from an external face of the sleeve by an excess length in a non-assembled state. The excess length is dimensioned such that the spring element is elastically moved radially inward by contact with the wall of the through opening when the sleeve is introduced into the through opening, so that the spring element presses against the wall 4 of the through opening as a result of elastic restoring forces.