Hybrid Motor Vehicle Shelf Assembly Weight Reduction
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Solution Overview
Problem
Existing rear speaker mounting shelf structures in motor vehicles are heavy and costly due to the use of steel for structural strength, which does not effectively reduce weight or incorporate attached components for load-bearing purposes.
Innovation Solution
A hybrid shelf assembly using a metallic body with polymeric modules that span component relief apertures, providing load-bearing capabilities and integrating reinforcement members and fastener receiving apertures, allowing for weight reduction and simultaneous injection molding of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel material is used for speaker mounting shelf structure to provide structural strength, then strength and stiffness are improved, but weight and cost increase
Solution Approach 1:
The patent uses a hybrid structure combining steel plates with polymeric modules. The polymeric modules (made from materials like polypropylene or polyamide) are injected into recesses in the steel plate, creating a composite structure that reduces weight while maintaining structural strength. This directly addresses the contradiction by replacing pure steel construction with a composite material system.
Solution Approach 2:
Instead of making the entire shelf structure from heavy steel, the patent applies polymeric modules only in specific locations where load-bearing is needed. The steel plate provides the basic structural framework, while polymeric reinforcement modules are strategically placed in recesses to provide localized strength where required, reducing overall weight while maintaining necessary strength characteristics.
2Stability of the object's composition
If additional metal is added to plate to provide stiffness for attached items, then structural stiffness is improved, but weight and cost increase
Solution Approach 1:
The patent implements localized reinforcement by placing polymeric modules with specific geometries (including ribs, protrusions, and varying wall thicknesses) into recesses at strategic locations on the steel plate. These modules provide stiffness exactly where needed to support attached items like speakers and seatbelt retractors, rather than adding weight throughout the entire structure.
Solution Approach 2:
The combination of steel plate and polymeric modules creates a composite structure where each material contributes its optimal properties. The steel provides baseline strength and stiffness, while the polymeric modules add localized stiffness and damping characteristics without the weight penalty of equivalent steel additions.
3Weight of moving object
If polymeric modules are used to span component relief apertures and provide load-bearing capability, then weight is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent combines multiple functions into the polymeric modules: they span component relief apertures, provide load-bearing capability, reinforce the steel plate structure, and can integrate mounting features for attached components. This merging of functions into single integrated modules actually reduces overall manufacturing complexity compared to assembling multiple separate components.
Solution Approach 2:
The patent replaces traditional mechanical assembly operations (welding, bolting, or riveting separate reinforcement pieces to the steel plate) with injection molding. The polymeric modules are injected directly into recesses in the steel plate, creating permanent bonds through the molding process itself. This substitution of injection molding for mechanical assembly reduces manufacturing steps and complexity.
Data Source
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AI summary
A motor vehicle hybrid shelf assembly includes a body formed of a metallic panel. Multiple modules attached to the body each molded of a polymeric material. At least one of the modules spans a component relief aperture created in the body. The at least one module spanning the component relief aperture defines a load bearing portion of the body replacing a load bearing capability of a body portion removed to define the component relief aperture. Each of the modules defines a first portion of an enclosure and includes at least one fastener receiving aperture for mechanical attachment of an independently provided second portion.