Vehicle Side-Member Overmolding for Rigidity and Cost Reduction

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Solution Overview

Problem

Current manufacturing methods for vehicle front face spars are costly and inefficient due to the need for multiple molds and material trimming, resulting in high investment and implementation costs, as well as scrap material, despite achieving satisfactory rigidity and weight reduction using hybrid metal-plastic or resin-fiber structures.

Innovation Solution

A structural part comprising a core made of a first material with reinforcing fibers, overmolded with a second material to provide stiffness, using a single molding tool and eliminating trimming operations, where the core is a sheet of textile material with fibers arranged in multiple directions and the second material forms ribs and interface zones, ensuring optimal rigidity and weight reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If resin plates filled with fibers are shaped by thermoforming and overmolded with plastic material, then weight is reduced, but manufacturing cost increases due to multiple molds and trimming operations

Engineering Contradiction:
Improveweight of side memberVSAvoidmanufacturing cost
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The invention merges the shaping and overmolding operations into a single integrated molding process. The mold includes a first cavity for shaping the resin plate with fibers and a second cavity for overmolding the plastic material, allowing both operations to be performed simultaneously in one cycle, thereby eliminating the need for separate trimming operations and reducing manufacturing cost while maintaining weight reduction benefits

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The molding apparatus is designed with multi-functionality to perform shaping, overmolding, and trimming operations within a single integrated system. The mold can shape the resin plate, overmold it with plastic material, and perform trimming all in one process cycle, making the device universal for multiple manufacturing operations that were previously required as separate steps

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Strength

If multiple molds are used for shaping and overmolding, then structural rigidity is achieved, but device complexity and investment cost increase

Engineering Contradiction:
Improvestructural rigidityVSAvoidnumber of molds
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention combines multiple molding operations into a single integrated mold system. The mold includes a first cavity for shaping the resin plate and a second cavity for overmolding the plastic material, allowing both operations to be performed simultaneously. This merging of operations maintains the structural rigidity achieved through multi-material construction while reducing the total number of separate molds and associated equipment

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If material trimming operations are performed, then manufacturing precision is improved, but productivity decreases and scrap material increases

Engineering Contradiction:
Improvedimensional accuracyVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention performs trimming operations as a preliminary integrated step within the molding process itself, rather than as a separate post-processing operation. The mold includes trimming elements that remove excess material during the molding cycle, ensuring dimensional accuracy is achieved during manufacturing rather than through subsequent trimming, thereby maintaining precision while improving productivity and reducing scrap

Inventive Principle:
Principle #10Preliminary action

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 simplifies the manufacturing process, reduces tooling costs, and achieves lightweight, rigid structural parts with improved efficiency and reduced material waste, while maintaining the structural integrity and shock absorption capabilities required for vehicle front face spars.

Implementation Method 1

Said plates are shaped beforehand by thermoforming

Methodology Applied
Scientific EffectThermoforming:

Implementation Method 2

a step of injecting the second material into the molding cavity is carried out so as to overmold the core with said second material

Methodology Applied
Scientific EffectInjection molding:

Data Source

PatentEP2768721B1Structural component, notably vehicle front end side-member, and method of manufacturing such a component
Publication Date: 2017.07.19 VALEO SYST THERMIQUES SAS
  • EP2768721B1 patent drawingFigure 1~2
  • EP2768721B1 patent drawingFigure 3a~3b
  • EP2768721B1 patent drawingFigure 4a~4b

AI summary

The invention relates to a structural component (1), notably a vehicle front end side-member, comprising a core (2) made of a first material incorporating reinforcing fibres (3), said core (2) being over-moulded with a second material (4) that gives the component its rigidity. The invention also relates to a front end of a vehicle, notably a motor vehicle, comprising such a component and to a method for the manufacture thereof.