Bent Sealing Strip Extrusion for Vehicle Body Gaps
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Solution Overview
Problem
Conventional sealing strips for vehicle bodies are either prefabricated in a straight shape and require bending, leading to unwanted folds, or are bent using a metal insert, which can cause wrinkling, and existing methods for extruding in a curved shape are inefficient.
Innovation Solution
The method involves extruding a thermoplastic elastomer sealing strip in a bent shape using uneven material flow through the extrusion tool and subsequent calibration to maintain the desired bend, ensuring precise adaptation to the gap without stress or folding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sealing strands are extruded in a straight shape and bent during installation, then the extrusion process is simple, but unwanted folds are formed
Solution Approach 1:
The sealing strand is extruded in a pre-bent shape that approximates the final gap contour, so that when installed, it requires minimal additional deformation. This preliminary shaping action prevents the formation of unwanted folds during installation while maintaining a relatively simple extrusion process.
Solution Approach 2:
The patent changes the extrusion parameters by using an asymmetric extrusion die and controlling the material flow rate distribution across the die cross-section. This creates different flow velocities at different locations, resulting in a bent strand shape upon extrusion without requiring complex post-processing.
2Manufacturing precision
If sealing strands are prefabricated in a bent form using a metal insert, then the bend shape is maintained, but wrinkling occurs
Solution Approach 1:
The patent removes the metal insert from the sealing strand structure entirely. Instead of using a metal reinforcement to maintain the bent shape, the sealing strand is extruded directly in the desired bent configuration using controlled material flow, eliminating the source of wrinkling while maintaining shape accuracy.
Solution Approach 2:
The sealing strand uses a composite structure with a thermoplastic elastomer matrix and embedded reinforcement elements that are integrated during extrusion. This composite approach provides the necessary structural support to maintain the bent shape without causing wrinkling, as the reinforcement is uniformly distributed rather than concentrated in a metal insert.
3Shape
If sealing strands are extruded in a curved shape using uneven speed distribution, then the bending is achieved, but the process complexity increases
Solution Approach 1:
The patent applies local quality control by creating an asymmetric extrusion die with varying land lengths and angles at different locations across the die cross-section. This causes the material to flow at different velocities in different regions, naturally forming a bent shape without requiring complex mechanical bending devices or post-extrusion processing.
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 method produces a sealing strip that can be easily installed with minimal stress and maintains a precise, permanent bend, effectively sealing and guiding vehicle window panes with reduced wrinkling and folding issues.
Implementation Method 1
the still soft thermoplastic elastomer material heated during the extrusion is increasingly cooled by the calibrating device 9 and completely or at least partially solidifies
Implementation Method 2
the still soft thermoplastic elastomer material heated during the extrusion is increasingly cooled by the calibrating device 9 and completely or at least partially solidifies
Implementation Method 3
the still soft thermoplastic elastomer material heated during the extrusion is increasingly cooled by the calibrating device 9 and completely or at least partially solidifies
Data Source
Figure 1~3
AI summary
The method involves extruding a sealing thread as a bent thread and bending the sealing thread after extrusion by plastic deformation and cooling of extruded material. Calibration elements (10) are directly arranged downstream in connection to extrusion of an opening of an extrusion tool (14) with respect to desired bending for bending the sealing thread. Elastomer material and/or thermoplastic elastomer and thermoplastic material are used for manufacturing the sealing thread, where the thermoplastic material forms a strand extended in a longitudinal direction of the sealing thread. An independent claim is also included for a sealing thread for sealing a gap at a vehicle body.