Overmoulded Composite Structural Parts with Pressurized Fluid Inserts
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Solution Overview
Problem
Existing methods for manufacturing hollow structural parts for motor vehicles, such as using foam inserts or gluing and riveting two parts together, result in increased weight, complex manufacturing processes, and unusable hollow volumes, failing to efficiently achieve mechanical properties like stiffness and lightness.
Innovation Solution
A method involving a hollow body made of composite material with an internal envelope filled with a pressurized fluid, where the fluid resists overmolding pressure and allows for a lightweight, functional part that can be pierced for wire or air channels, balancing internal and external pressures to prevent explosions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If foam inserts are used to form hollow bodies in structural parts, then mechanical properties such as stiffness and rigidity are improved, but the weight of the part increases considerably
Solution Approach 1:
The patent changes the physical state of the filling material from solid foam to pressurized fluid, which has lower density and weight while maintaining the ability to resist compression forces during molding, thereby improving the strength-to-weight ratio
Solution Approach 2:
The patent uses pressurized fluid (gas or liquid) instead of solid foam inserts. The pressurized fluid provides structural support during molding through fluid pressure, achieving the necessary stiffness while significantly reducing the weight of the hollow body
2Strength
If foam inserts are used to form hollow bodies, then mechanical properties are improved, but the hollow volume becomes unusable and adds weight
Solution Approach 1:
The patent enables the hollow volume to serve multiple functions: it provides structural rigidity during molding through pressurized fluid, and after molding, the fluid can be removed to create a functional hollow space for wire passages, air channels, or other purposes, making the same volume versatile rather than wasted
3Shape
If two parts are glued and riveted to form a hollow body, then the hollow structure is achieved, but the manufacturing process becomes complex and time-consuming
Solution Approach 1:
The patent combines the hollow body formation with the molding process itself by using a removable insert that defines the hollow space. The insert is placed in the mold, the material is molded around it in a single operation, and then the insert is removed, eliminating the need for separate gluing and riveting operations to create hollow structures
4Shape
If two parts are glued and riveted to form a hollow body, then the hollow structure is achieved, but the manufacturing steps are lengthened and precision requirements increase
Solution Approach 1:
The patent performs preliminary action by placing the insert in the mold before molding, which pre-defines the hollow body shape and eliminates the need for subsequent assembly operations. This preliminary positioning of the insert streamlines the entire manufacturing process and improves productivity
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 lightweight, structurally reinforced parts with enhanced stiffness and resistance, addressing weight concerns and simplifying the manufacturing process while ensuring safety by balancing pressures and enabling multiple functional uses.
Implementation Method 1
the insert consisting of a sealed sealed envelope containing a pressurized fluid; and closing the mold by compressing the sheet and the insert at a compression pressure equal to or less than the pressure of the fluid
Data Source
Figure 1~3
Figure 4A~4F
Figure 5~6
AI summary
The invention relates to a structural part (1) of a motor vehicle, produced from a composite material containing reinforcing fibres. Said part (1) comprises a part in the form of a hollow body defined by an inner envelope (3) having an inner space (4). The inner envelope (3) is overmoulded by a layer of the composite material and the inner space (4) of the inner envelope (3) is entirely occupied by a fluid.