Blind Rivet Structure for High-Strength Load Transfer and Damping
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Solution Overview
Problem
Existing blind rivets face strength limitations and material compatibility issues, leading to potential twisting and surface pressure problems, especially when used with high-strength screws, and may not form a stable stress unit due to inadequate axial fixation and adhesive forces between the outer body and inner bushing.
Innovation Solution
A blind rivet design featuring an elastic outer body with a sleeve-shaped shaft, a metal bushing, and a fixing sleeve that limits radial expansion, ensuring reliable fixation and vibration damping, with a conical end section for precise positioning and load transfer, and a distributor disc for optimal load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the blind rivet nut is designed for high-strength screw connection (strength class > 8.8), then the connection strength is improved, but the elastic outer body is subject to unacceptable twisting and excessive surface pressure
Solution Approach 1:
The blind rivet is divided into distinct functional segments: a rigid metal threaded insert for high-strength load bearing, an elastic outer body for sealing and damping, and a fixing flange for axial positioning. This segmentation allows each component to optimize its properties for its specific function, resolving the contradiction between strength and stability.
Solution Approach 2:
The blind rivet combines metal (threaded insert) and elastic material (outer body) into a composite structure. The metal insert provides the necessary strength for high-strength screw connections, while the elastic outer body provides stability, sealing, and damping. This composite approach resolves the contradiction by distributing different requirements to different materials.
2Ease of manufacture
If the threaded bushing is formed in one piece, then the manufacturing complexity is reduced, but the axial force cannot be properly distributed leading to excessive surface pressure
Solution Approach 1:
The blind rivet is segmented into a metal threaded insert and an elastic outer body that can be manufactured separately using different optimal processes (metal forming and injection molding), then assembled. This segmentation allows the threaded insert to be optimized for thread formation while the outer body optimizes for elastic properties, resolving the contradiction between manufacturing ease and stress distribution.
3Ease of manufacture
If the outer body is not sufficiently axially fixed, then the injection molding process is simpler, but the outer body comes off the bushing during compression
Solution Approach 1:
The fixing flange acts as an intermediary element between the elastic outer body and the metal threaded insert. It provides axial positioning and retention forces that prevent the outer body from detaching during compression, while allowing the outer body to be manufactured separately via injection molding. This intermediary structure resolves the contradiction between manufacturing simplicity and fixation reliability.
Solution Approach 2:
The metal threaded insert is nested within the elastic outer body, with the fixing flange providing axial retention. This nested configuration allows the outer body to be injection molded around the insert, ensuring proper axial fixation while maintaining manufacturing simplicity through a single-step co-molding or assembly process.
4Adaptability or versatility
If adhesive forces between inner bushing and outer body are insufficient, then the material selection is more flexible, but the blind rivet does not form a stressable unit
Solution Approach 1:
The blind rivet is segmented into a metal threaded insert and an elastic outer body that remain as distinct components with a defined interface. This segmentation allows independent optimization of materials for each component (metal for strength, elastic material for sealing and damping) while mechanical interlocking features ensure stress transfer, resolving the contradiction between material flexibility and stress transfer capability.
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 provides a stable and reliable screw connection under diverse environmental conditions and material combinations, preventing axial displacement and material failure, while maintaining effective damping properties and load transfer.
Implementation Method 1
an elastic outer body with a sleeve-shaped shaft which comprises a fastening flange and a hollow cylindrical folding zone which is foldable to an upsetting bulge
Data Source
AI summary
A blind rivet for establishing a screw connection between a support component and a fastening part has an elastic outer body and a metal bushing arranged therein. The outer body is at least partially surrounded by a fixing sleeve which fixes the outer body on an end portion in the metal bushing.