Coil Spring Support Groove Structure to Prevent Adhesive Weld Lines
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Solution Overview
Problem
Conventional coil spring devices face the issue of weld lines forming on the outer surface of the adhesive layer between the main body spring and the support groove, which can lead to the entry of foreign substances.
Innovation Solution
The coil spring device features a support groove with spacer protrusions that have varying inclination angles and widths, causing adhesive flows to interfere and merge before reaching the open end edge, preventing the formation of weld lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adhesive flows toward the open end edge of the support groove during the bonding process, then the lower end portion of the main body spring adheres to the inner surface of the support groove, but weld lines are generated on the outer surface of the adhesive layer and foreign substances may enter the exposed portion
Solution Approach 1:
The support groove is divided into multiple intervals by spacer protrusions, which segment the adhesive flow path. This segmentation prevents the adhesive from forming continuous weld lines by creating multiple separate flow zones that are controlled by the spacer protrusions.
Solution Approach 2:
The spacer protrusions are strategically positioned at specific locations within the support groove to locally control the adhesive flow. Each spacer protrusion creates a localized flow pattern that prevents weld line formation in critical areas while maintaining adhesion in other regions.
2Ease of manufacture
If the adhesive is pressed into the lower end portion of the main body spring to spread the adhesive, then bonding is achieved, but the adhesive flow merges after branching by the spacer protrusion and reaches the open end edge in a rectified state
Solution Approach 1:
The spacer protrusions are pre-formed on the inner surface of the support groove before adhesive application. These protrusions are positioned to preliminarily guide and control the adhesive flow path, ensuring that the adhesive branches and merges in a controlled manner that prevents weld line formation.
Solution Approach 2:
The spacer protrusions act as intermediary structures that mediate the adhesive flow between the application point and the open end edge. They control the flow pattern by creating branch points and merge points, preventing the adhesive from forming rectified flow patterns that lead to weld lines.
Data Source
Figure 1
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AI summary
A coil spring device includes: a main body spring and an insulator (12), the insulator is provided with a support groove (13) which extends around a coil axis and into which a lower end portion of the main body spring is fitted, the lower end portion of the main body spring adheres to an inner surface (13a) of the support groove, the inner surface of the support groove is provided with a plurality of spacer protrusions (14, 15) which support an outer peripheral surface of a wire rod, a plurality of adjacent spacer protrusions (14) adjacent to an open end edge (21) of the support groove of the plurality of spacer protrusions each includes a pair of side wall surfaces (14a, 14b) extending toward the open end edge and are provided at intervals (A) therebetween in an extension direction of the open end edge in a plan view of a part including the open end edge in the inner surface of the support groove, and inclination angles (θ1, θ2) of the side wall surfaces adjacent to each other in the extension direction with the interval therebetween with respect to an orthogonal direction orthogonal to the open end edge are different from each other in the plan view.