Vehicle Wheel Disc Flange Notch Design for Cracking Prevention
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Solution Overview
Problem
Steel wheels with thin spokes and large decorative holes suffer from reduced rigidity and material thickness near decorative holes, leading to deformation and cracking during the forming process, which compromises the durability and strength of the wheel.
Innovation Solution
A wheel design featuring a disc flange with notches cut out at the radially outside end of each spoke, where the minimum distance between the notch and the decorative hole is smaller than the disc flange width, allowing material to flow and prevent cracking, and a middle piece extending towards the rim for enhanced strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the disc is provided with larger decorative holes to reduce material and improve appearance, then the aesthetic quality and weight reduction are improved, but the disc flange has lower rigidity and material thickness near decorative holes, causing deformation and cracking during forming
Solution Approach 1:
The patent applies local quality by providing a reinforcing rib specifically at the disc flange portion near the decorative hole corners, where strength is most needed. This localized reinforcement allows the overall disc to maintain large decorative holes for aesthetic purposes while preventing cracking and deformation at critical locations during the forming process.
Solution Approach 2:
The patent creates a composite structure by integrating a reinforcing rib (made of metal material) into the disc flange structure. This composite approach combines the aesthetic requirements of large decorative holes with the structural necessity of reinforced areas, allowing material to flow into the rib during forming to prevent cracking.
2Loss of substance
If thin spokes and large decorative holes are used to reduce material usage and lower cost, then weight and material consumption are reduced, but the ring portion has minimum width and lowest strength, causing poor welding and insufficient joint strength
Solution Approach 1:
The reinforcing rib is strategically positioned at the disc flange portion where the ring portion connects to the rim, providing localized strength enhancement exactly where welding joint strength is critical. This allows the rest of the structure to maintain thin spokes and large decorative holes for material reduction.
Solution Approach 2:
The reinforcing rib is formed as an integral part of the disc flange before the welding process. By pre-forming this reinforcement structure, the patent ensures that the ring portion has sufficient strength and stable geometry ready for welding, preventing welding defects and ensuring adequate joint strength without requiring additional material throughout the entire structure.
3Productivity
If the disc flange is formed by pressing after punching decorative holes, then manufacturing efficiency is improved, but the disc flange near decorative hole corners is drawn, reducing material thickness and causing edge cracking
Solution Approach 1:
The reinforcing rib is formed as part of the disc flange structure before the pressing operation. During the pressing process, material flows into the reinforcing rib, which prevents the drawing effect that would otherwise reduce material thickness at the decorative hole corners. This preliminary structural preparation enables efficient pressing while maintaining material thickness uniformity.
Solution Approach 2:
The patent converts the potential harm of material drawing during pressing into a benefit by designing the reinforcing rib to receive the flowing material. The material that would otherwise be lost to thinning and cracking is instead directed into the reinforcing rib, enhancing the structure where it is most needed while preventing defects.
Data Source
AI summary
An automobile wheel 10 comprising: (a) a rim 20; and (b) a disc 30 including: a plurality of spokes 33; and a disc flange 35 positioned at an outside end in the wheel radial direction, the disc having decorative holes 34, in which the rim and the disc flange are joined together, wherein a part of the disc flange, which corresponds to a radially outside end S of each of the spokes, is cut out toward an outside in a wheel axial direction relative to a disc-flange inside end edge 35a of the disc flange on an inside in the wheel axial direction to form a notch 36, and a minimum distance a1 between the notch and an outer periphery of the decorative hole is smaller than a width a2 of the disc flange at a middle position CD of the decorative hole.