Motor Vehicle Seat Cushioning Mold Segmentation for Heel Sealing
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Solution Overview
Problem
Existing methods for producing motor vehicle seat padding face challenges in ensuring a good seal at the heel, maintaining correct positioning, producing padding with distinct densities for varying flexibility, and achieving strong adhesion of the foam to the yokes, particularly due to non-cohesion issues between the foam and yokes during repeated use.
Innovation Solution
The method involves a mold design with a beak-shaped section and a blade-like low wall to overmold the heel, ensuring a seal and correct positioning, while using different foam precursor mixtures for distinct densities and applying a film to prevent foam penetration, resulting in a padding with marked flexibility differences and strong adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heel is not properly sealed, then the positioning is simple, but foam passage occurs towards the face of the padding
Solution Approach 1:
The first half-mold is divided into two separate parts that can be positioned in close configuration to pinch the cap at the seam level. This segmentation allows the heel to be properly sealed by forcing it between the two parts, preventing foam passage while maintaining a relatively simple overall mold structure.
Solution Approach 2:
The invention introduces a vertical dimension to the sealing process by having the two parts of the first half-mold pinch the cap vertically at the seam level. This dimensional approach creates effective sealing at the heel without requiring complex horizontal sealing mechanisms.
2Manufacturing precision
If the heel positioning is not controlled, then the mold structure is simple, but the heel position relative to the interface is incorrect
Solution Approach 1:
The cap is pre-positioned in the open mold with the front face against the first wall before the two parts are brought into close configuration. This preliminary positioning ensures that the heel is correctly located relative to the interface between the two parts, achieving precise heel positioning without requiring complex positioning mechanisms.
Solution Approach 2:
The heel positioning is achieved through the self-aligning nature of the pinching action. When the two parts are brought into close configuration, they automatically pinch the cap at the seam level and position the heel correctly relative to the interface, without requiring additional positioning devices.
3Adaptability or versatility
If the foam density is uniform, then the manufacturing process is simple, but the flexibility is not differentiated across the yokes
Solution Approach 1:
The invention applies local quality by injecting foam precursor mixtures with different densities into different zones of the molding cavity. Specifically, a first foam precursor mixture is injected towards the first yoke and a second foam precursor mixture with different density is injected towards the second yoke, creating padding with differentiated flexibility in different regions to adapt to different comfort requirements.
4Strength
If the foam adheres weakly to the yokes, then the mold structure is simple, but tearing occurs during repeated use
Solution Approach 1:
The segmentation of the first half-mold into two parts that can be brought into close configuration creates a pinching action at the seam level. This mechanical action ensures strong adhesion of the foam to the yokes by forcing the foam precursor mixture into intimate contact with the yoke surfaces during expansion, preventing tearing during repeated use without requiring additional adhesion-promoting devices.
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
This approach ensures a good seal, correct positioning, and distinct flexibility across the yokes, preventing foam tearing and maintaining hygrothermal comfort by avoiding foam mixture during initial expansion and ensuring strong adhesion of the foam to the yokes.
Implementation Method 1
injecting a precursor mixture of elastically compressible polyurethane foam into said molding cavity, so as to form, by expansion of said foam, a block of padding
Data Source
Figure 1~2
AI summary
The invention concerns a method in which the first portion (14) is provided with a peripheral area (26) that grows thinner towards the free rim (27) of same, such that it has a cross section in the form of a tip pointing towards the second portion (16); said second portion is provided with a peripheral wall (21) in the form of a tongue, said wall protruding towards the inside of the moulding cavity (11); the heel (6) is arranged, when the cover (2) is positioned in the mould, in such a way that the seam (5) comes close to said free rim, the underlays (3, 4) extending respectively to either side of said area, the second face (28) pressing against said wall, said wall extending at least to a free end of the heel (6), such that said heel is overmouded by said foam, once expanded, on the edge (29) and on the first surface (30), said second surface being substantially free of foam.