Composite Fastening Device Vibration Damping
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Solution Overview
Problem
Existing fastening devices for hoses to threaded stems in motor vehicles inadequately dampen vibrations, leading to unsatisfactory noise reduction, as damping is concentrated only in coupling zones between hoses and clamps.
Innovation Solution
A fastening device comprising a co-moulded supporting body of different plastic materials with a relatively rigid external portion and a softer internal portion, featuring elastically deformable radial projections and a fastening pin with teeth, which distributes vibration damping across the attachment portion and threaded stem, enhancing noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single piece of thermoplastic material is used for the fastening device, then the device complexity is reduced and manufacturing is simplified, but the vibration damping performance is insufficient
Solution Approach 1:
The attachment portion is constructed as a composite structure with two distinct plastic materials: a rigid material for the external portion providing structural support, and a soft material for the internal portion providing vibration damping. This composite approach enables both structural integrity and effective vibration damping without increasing device complexity, as the composite attachment portion is still formed as a single integrated component.
Solution Approach 2:
Different regions of the attachment portion are assigned different material properties tailored to their specific functions. The external portion uses rigid material for structural support and positioning, while the internal portion uses soft material for vibration damping. This local differentiation of material quality optimizes performance while maintaining a relatively simple single-piece construction.
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 solution effectively dampens vibrations and noise by distributing damping across the attachment portion and threaded stem, improving noise reduction compared to previous solutions.
Implementation Method 1
the softer material extends continuously in order to define the internal portion (21) and the flanges (26, 27). Said material is also less rigid and less hard than the material of the fastening pin (31). In use the vibrations are also damped in the coupling zones between the threaded stem (3) and the attachment portion (11) of the body (10), and not only in the coupling zones between the clamps (12) and the respective hoses
Implementation Method 2
Along the surface of the hole (22), the internal portion (21) comprises a series of radial projections (25) that are elastically deformable under compression
Implementation Method 3
the stem (34) has a plurality of teeth (35), which engage in the respective grooves of the thread of the threaded stem (3) when the fastening pin (31) is in the hole (22), so as to axially restrain the fastening pin (31). The outside diameter of the stem (34) is larger than the diameter of the hole (22), when it is out of the attachment portion (11). When it is inserted in the hole (22), the stem (34) comes into contact with the relatively soft material that defines the internal surface of the hole (22), so that it compresses such material elastically in a radial direction.
Data Source
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AI summary
A fastening device (1) for connecting at least one hose to a threaded stem (3) has a supporting body (10) provided with an attachment portion (11) and a side clamp (12) configured in such a way as to be tightened around the hose; the attachment portion (11) has an external portion (20) and a softer internal portion (21) which defines a through hole (22); the fastening device also has a fastening pin (31) with an axial stem (34), which is axially hollow for housing the threaded stem (3); the axial stem (34) is inserted in the through hole (22) and remains in contact with the softer material of the internal portion (21), which therefore cooperates in damping vibrations.