Wheel Spoke Head Rear Surface Design for Flash Concealment
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Solution Overview
Problem
The use of open-matrix moulds for wheel spoke manufacturing inevitably results in flash or indentations on the head rear surface, leading to stress peaks and potential fracture, especially when spokes and hubs are made of brittle materials, and existing solutions like closed-matrix moulds are impractical for removal due to the length of the spoke shaft.
Innovation Solution
A wheel spoke design featuring a head rear surface with alternating raised portions and recesses that conceal flash and indentations, allowing for improved strength and reduced rotation risk, produced using an open-matrix mould with specific configurations to accommodate the spoke's length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an open-matrix mould is used for manufacturing the spoke, then the spoke can be removed from the mould, but flash or indentations are formed on the head rear surface causing stress peaks and potential fracture
Solution Approach 1:
The head rear surface is designed with localized alternating raised portions and recesses instead of a uniform smooth surface. This local differentiation allows the recesses to specifically target and conceal flash defects while the raised portions maintain structural integrity and load-bearing capacity, resolving the contradiction between ease of manufacture and reliability.
Solution Approach 2:
The invention converts the harmful flash defects into a beneficial feature by using the recesses to deliberately conceal and distribute the flash. Instead of trying to eliminate flash completely, the design accepts its presence and transforms it from a fracture-causing defect into a controlled feature that actually improves load distribution and prevents stress concentration.
2Reliability
If a closed-matrix mould is used to eliminate flash, then a perfectly smooth head rear surface is obtained, but the spoke cannot be removed from the mould due to its considerable length
Solution Approach 1:
The head rear surface is segmented into multiple alternating raised portions and recesses rather than being a continuous smooth surface. This segmentation allows the surface to accommodate flash from open-matrix moulding while maintaining overall smoothness and structural integrity, enabling both defect tolerance and manufacturability.
3Strength
If the head rear surface is made smooth to distribute load evenly, then strength is improved, but rotation between the head and seat occurs under tension
Solution Approach 1:
The head rear surface employs asymmetric alternating raised portions and recesses rather than a symmetric smooth surface. This asymmetric pattern provides both load distribution through the varied surface topology and rotational stability through the irregular geometry that prevents uniform rotation, simultaneously achieving strength and stability.
Solution Approach 2:
The raised portions and recesses create a curved, non-planar surface topology on the head rear surface. This curvature provides mechanical interlocking with the hub seat, preventing rotation while the distributed surface features maintain even load distribution, achieving both strength and rotational stability.
Data Source
AI summary
A wheel spoke includes a shaft, a head at an axial end of the shaft, and a head rear surface on the face of the head which faces towards the shaft; the head rear surface has a plurality of alternating raised portions and recesses which can define a discontinuous contact surface.