Composite Bicycle Spoke With Integral Threaded Ends
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Solution Overview
Problem
Existing bicycle wheel spokes made of metal are heavy and complex to manufacture, while composite material spokes are lightweight but difficult to service and manufacture, and existing composite spokes with metallic ends are also complex to produce.
Innovation Solution
A spoke made of fibrous composite material with embedded reinforcing elements, particularly long fibers, is manufactured integrally by pultrusion, with end portions configured to connect to the hub and rim, featuring a threaded portion and a smooth surface without loops or eyelets, ensuring high stability and ease of manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal spokes are used, then high strength and reliability are achieved, but weight increases
Solution Approach 1:
The patent employs composite materials consisting of a matrix material and embedded reinforcing elements (such as glass fibers, carbon fibers, or aramid fibers) to manufacture spokes that combine the high strength of metal with reduced weight. The composite structure provides tensile strength comparable to metal while significantly lowering the density, thus resolving the contradiction between strength and weight.
2Weight of moving object
If composite material spokes are manufactured directly with the rim, then weight is reduced, but manufacturing complexity increases and serviceability decreases
Solution Approach 1:
The patent divides the wheel into separate components: the rim, the spokes, and the hub. The spokes are manufactured as independent composite components using pultrusion or injection molding, then assembled to the rim and hub. This segmentation reduces manufacturing complexity compared to monolithic composite wheels, enables individual replacement of defective spokes, and maintains low weight.
Solution Approach 2:
The patent enables individual spoke replacement when defects occur, rather than discarding the entire wheel. This improves sustainability and reduces waste, as only the affected spoke needs to be replaced while the rest of the wheel structure can be retained and reused.
3Strength
If separate metallic ends are added to composite spokes, then connection points are strengthened, but manufacturing complexity increases
Solution Approach 1:
The patent integrates the connection features (such as threaded portions, cranked heads, or attachment points) directly into the composite spoke body during manufacturing. The reinforcing elements extend into these connection zones to maintain strength, eliminating the need for separate metallic end pieces while preserving connection integrity and simplifying the overall structure.
4Strength
If long fibers extend through the entire spoke, then tensile strength is maximized, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs specific manufacturing processes (pultrusion or injection molding) that control fiber orientation and distribution through parameter optimization. The process parameters (temperature, pressure, fiber length, mold design) are adjusted to ensure long fibers align with the spoke axis and distribute uniformly, achieving maximum tensile strength while maintaining manufacturability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a lightweight, robust, and easily manufactured wheel component with high stability under load, preventing settling phenomena and allowing for efficient assembly without separate adhesive layers, while maintaining high tensile strength and aerodynamic shape.
Implementation Method 1
The spoke is manufactured from at least one fibrous composite material and comprises at least one matrix material with reinforcing elements embedded therein. At least some of the reinforcing elements are configured as long fibers, extending through the entire center portion and over at least a substantial part of the two spoke end portions.
Implementation Method 2
At least some of the reinforcing elements are configured as long fibers, extending through the entire center portion and over at least a substantial part of the two spoke end portions. At least one end portion comprises a cross-sectional region with long fibers embedded therein as reinforcing elements
Data Source
AI summary
A wheel component for bicycles with a straight spoke, with a center portion and two end portions, to detachably connect a hub with a rim. The spoke is supported on a hub and a rim by the end portions. The spoke is manufactured from a fibrous composite material and includes a matrix material and embedded reinforcing elements. The spoke is formed without loops and eyelets. The end portions are integral with the center portion, forming an end of the spoke each. At least one of the two end portions includes a threaded portion. At least some of the reinforcing elements are configured as long fibers extending through the entire center portion and over at least a substantial part of the two end portions each. At least one end portion includes a cross-sectional region with embedded reinforcing long fibers, and at least one cross-sectional portion without reinforcing embedded long fibers.