Integrated Spoke Wheel Assembly Reducing Weight and Cost

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Solution Overview

Problem

Existing wheel assemblies for electric bicycles face challenges in reducing manufacturing costs and weight while maintaining rigidity, and they often require complex spoke structures that increase installation time and material costs, with integrated plastic wheels offering low rigidity and vulnerability to external impacts.

Innovation Solution

A wheel assembly featuring an integrated-type spoke structure formed by injection molding, where a metal hub with higher rigidity is combined with plastic spokes and reinforcing members, reducing material costs and weight, and allowing for easy assembly and potential replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a spoke structure is formed using a plurality of steel lines connecting the rim to the hub, then a desired rigidity is provided, but the material cost is increased and installation complexity increases

Engineering Contradiction:
ImproverigidityVSAvoidinstallation complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the hub, spokes, and rim into a single integrated wheel structure formed by one piece through injection molding. This eliminates the need for separate steel lines and multiple installation steps, reducing installation complexity while maintaining structural integrity through the integrated design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite materials, specifically glass fiber reinforced plastic, to achieve the desired rigidity in the integrated wheel structure. The glass fibers provide enhanced strength and stiffness to the plastic matrix, allowing the single-piece structure to meet rigidity requirements without using traditional steel spokes.

Inventive Principle:
Principle #40Composite materials

2Strength

If the spoke structure is formed of metal, then a desired rigidity is provided, but the material cost is increased

Engineering Contradiction:
ImproverigidityVSAvoidmaterial cost
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent employs glass fiber reinforced plastic as a composite material that provides metal-like rigidity and strength at lower cost. The glass fibers embedded in the plastic matrix create a high-strength, stiff structure that replaces expensive metal spokes while maintaining the required mechanical properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters by using reinforced plastic instead of metal, and optimizes the structural parameters through the integrated one-piece design. This combination of material and structural parameter changes achieves the desired rigidity with lower material cost.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If an integrated type wheel is formed of plastic, then the manufacturing process is simplified, but the rigidity is low and the wheel may be easily damaged by external impact

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidrigidity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent uses glass fiber reinforced plastic to overcome the inherent weakness of plain plastic. The glass fibers significantly enhance the rigidity and impact resistance of the plastic material, allowing the integrated wheel to maintain both manufacturing simplicity and structural strength.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent incorporates reinforcing members with through-holes that create a segmented reinforcement pattern within the integrated structure. These strategically placed reinforcing members enhance local rigidity and impact resistance in critical areas while maintaining the overall integrated design and manufacturing simplicity.

Inventive Principle:
Principle #1Segmentation

4Ease of manufacture

If a hub is coupled to the rotating shaft in the integrated type wheel, then the wheel structure is completed, but additional installation components and time are required

Engineering Contradiction:
Improveassembly process simplicityVSAvoidinstallation time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent merges the hub into the single-piece integrated wheel structure formed by injection molding. The hub is no longer a separate component that needs to be installed; it is inherently formed as part of the wheel body, eliminating additional installation steps and time while completing the wheel structure in one manufacturing process.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2712742B1Motor housing integrated-type spoke for electric bicycle, manufacturing method thereof, wheel assembly having the same and manufacturing method thereof
Publication Date: 2019.05.01 HL MANDO CORP
  • EP2712742B1 patent drawingFigure 1
  • EP2712742B1 patent drawingFigure 2~3
  • EP2712742B1 patent drawingFigure 4

AI summary

An integrated type spoke structure, a wheel assembly for a bicycle having the same, and a manufacturing method thereof, the integrated type spoke structure for a spoke coupled to a rim, the spoke including a reinforcing member provided at an end portion of the spoke formed of plastic, and a hub provided at a center of the spoke, wherein the reinforcing member and the hub are formed of material having rigidity larger than a rigidity of the spoke, and are integrally formed with each other through an injection molding.