Steering Wheel Rim Segmentation for Weight and Cost Reduction
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Solution Overview
Problem
Current decorative steering wheels made of injection molded polyurethane are expensive, and there is a need for a cost-effective method to create steering wheels with decorative patterns, such as wood patterns, while maintaining weight reduction and structural integrity.
Innovation Solution
A steering wheel design featuring a rotatable rim composed of an armature, a first rim portion with a decorative pattern, and a second rim portion made of two shells with a soft pliable cover, where the second rim portion covers part of the first rim portion, and is manufactured through injection molding of ABS resin with a film applied for the pattern, reducing weight by defining a space between the shells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If injection molded polyurethane is used for steering wheel rims, then structural integrity and durability are improved, but manufacturing cost increases
Solution Approach 1:
The steering wheel rim is divided into multiple segments including an armature, first rim portion, and second rim portion that can be manufactured separately and then assembled. This segmentation allows each part to be optimized for its specific function and manufactured using cost-effective processes rather than requiring expensive monolithic polyurethane injection molding for the entire structure.
Solution Approach 2:
The patent employs composite construction by combining different materials and components - the armature provides structural support, the first rim portion offers decorative surfaces, and the second rim portion adds functional coverage. This composite approach replaces solid polyurethane with a multi-material assembly that achieves comparable structural integrity at lower cost.
2Strength
If solid polyurethane material is used for the rim, then structural strength is improved, but weight increases
Solution Approach 1:
By segmenting the rim into separate components (armature, first rim portion, second rim portion) with potential gaps or spaces between them, the patent reduces material usage while maintaining structural strength through the distributed framework of the armature and interlocking portions.
Solution Approach 2:
The second rim portion acts as a flexible covering element that provides structural completion and aesthetic finish without the weight of solid polyurethane. This shell-like component reinforces the overall structure while adding minimal weight compared to a solid construction.
3Shape
If decorative patterns are added to the rim surface, then aesthetic appeal is improved, but manufacturing complexity increases
Solution Approach 1:
The decorative functionality is separated into the first rim portion, which can be manufactured with decorative patterns integrated into its structure or surface. This segmentation allows the decorative element to be produced as a distinct component, potentially through simpler processes like molding or surface treatment, rather than requiring complex integrated manufacturing of the entire rim.
Solution Approach 2:
The first rim portion with decorative patterns can be manufactured as a cost-effective, potentially replaceable component. Decorative elements are applied to this portion which can be produced more economically than high-end polyurethane rims, allowing for aesthetic customization without proportionally increasing manufacturing complexity.
Data Source
AI summary
A steering wheel includes a rim that is rotatable around a steering shaft. The rim includes an armature; a first rim portion surrounding the armature; and a second rim portion, covering part of the surface of the first rim portion. A method of manufacturing a steering wheel includes providing an armature; injection molding a first rim portion such that the it surrounds the armature; injection molding a second rim portion; and attaching the first and second rim portions such that the second rim portion covers part of the surface of the first rim portion.