Wheel Well Liner Hinge Design for Injection Molding

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Solution Overview

Problem

Existing methods for producing curved components, such as wheel well liners, face challenges with material weakening at bending points, leading to potential cracks, stress whitening, and bottlenecks in injection molding processes, which complicate assembly and increase costs.

Innovation Solution

A method where components are produced in a spread-out form with reduced material strength at bending points by 40% to 60%, allowing for curvature without material weakening, and enabling uniform plastic flow during injection molding without bottlenecks, using a design that distributes stress harmoniously and eliminates the need for expensive slides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If a classic film hinge is used to enable stacking of curved components, then packing density is improved, but material weakening and cracks occur at the kink area

Engineering Contradiction:

Improvepacking densityVSAvoidmaterial strength at bending point

Core Design Contradiction:

Volume of stationary objectVSStrength

Solution Approach 1:

The patent applies local quality by creating a hinge area with locally reduced material thickness (40-60% thinner than adjacent areas) specifically at the bending point, while maintaining full thickness in other areas. This localized thinning enables the hinge functionality and stacking capability without compromising the overall structural integrity of the component.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of material thickness at the hinge location, reducing it by 40-60% compared to adjacent areas. This parameter change allows the material to bend and fold at the hinge point without causing stress concentration, cracks, or stress whitening, while still providing sufficient strength for the component's functional requirements.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If one-piece curved components are produced to simplify assembly, then assembly complexity is reduced, but packing density deteriorates due to unused space

Engineering Contradiction:

Improveassembly complexityVSAvoidpacking density

Core Design Contradiction:

Device complexityVSVolume of stationary object

Solution Approach 1:

The patent applies segmentation by introducing a hinge area that divides the one-piece component into foldable sections. The component remains manufactured as a single piece without separate parts, but the hinge creates a functional segmentation that allows the component to be folded into a compact configuration for efficient stacking and transportation, reducing the space required by 40-60%.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If material thickness is reduced at the bending point to enable folding, then ease of folding is improved, but material strength and reliability deteriorate

Engineering Contradiction:

Improveease of foldingVSAvoidmaterial reliability at bending point

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent provides beforehand cushioning by designing the hinge area with sufficient length (10-20 times the original thickness) and appropriate thickness reduction, which prevents stress concentration and material failure during folding. This pre-designed hinge structure absorbs and distributes stresses harmoniously, preventing cracks and stress whitening before they can occur.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Ease of manufacture

If conventional injection molding is used for curved components, then manufacturing capability is maintained, but bottlenecks occur at the film hinge area

Engineering Contradiction:

Improveinjection molding capabilityVSAvoidmolding speed

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent changes the physical parameter of material thickness at the hinge location, reducing it by 40-60% compared to adjacent areas. This parameter change allows the material to flow uniformly during injection molding without creating bottlenecks, while still providing sufficient strength for the component's functional requirements.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11472075B2Method for the production of components with a bending point and such a component

Publication Date: 2022.10.18 VOLKSWAGEN AG

AI summary

To provide a method for the production of components, in particular wheel well liners of vehicles, in which the component is produced in a spread out or unfolded form and at a later time is moved into a curved or folded form, wherein in an area of a bending point, a material strength of the component decreases as compared to a material strength of the adjacent area, it is suggested that the minimum thickness of the material in the area of the bending point is molded to be 40% to 60%, preferably 45% to 55%, more preferably about 50% less than the material strength of the adjacent area.