Bicycle Rim Composite Layering for Stiffness and Weight

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Solution Overview

Problem

Existing bicycle rims are complex and expensive to manufacture, often lacking the necessary robustness and stiffness for high-quality mass market applications.

Innovation Solution

A bicycle rim design featuring a braided layer with continuous fibers and a reinforcement layer of 0° fibers or standing threads, integrated into the nipple bed and rim flanges, using a core that can be removable and made of foam or low-melting metal alloys, with a biaxial or triaxial braid structure for enhanced strength and lightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional steel or aluminum bicycle rims are used, then durability and robustness are improved, but weight increases

Engineering Contradiction:
ImproverobustnessVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent employs fiber composite materials consisting of multiple layers including a cover layer, reinforcement layers with 0° fibers, and braided layers. This composite structure achieves both lightweight properties and high mechanical strength, resolving the contradiction between weight reduction and robustness maintenance.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If carbon fiber composite rims are used to reduce weight, then weight is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
ImproveweightVSAvoidmanufacturing complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The rim is divided into distinct functional layers: cover layers for surface protection, reinforcement layers with 0° fibers for structural strength, and braided layers for dimensional stability. This segmentation allows each layer to be optimized independently while simplifying the overall manufacturing process through modular construction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the rim receive different fiber orientations and layer configurations tailored to local stress requirements. The reinforcement layers with 0° fibers are strategically placed in high-stress areas, while braided layers provide overall structural integrity, achieving optimal performance without uniform over-engineering.

Inventive Principle:
Principle #3Local quality

3Weight of moving object

If fiber composite rims are used to achieve lightness, then weight is improved, but stiffness and robustness decrease

Engineering Contradiction:
ImproveweightVSAvoidstiffness
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The multi-layer fiber composite structure combines materials with different mechanical properties. The reinforcement layers with 0° fibers provide high longitudinal stiffness, while the braided layers contribute to transverse strength and overall structural rigidity, achieving both lightness and stiffness simultaneously.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent transitions from single-direction fiber reinforcement to multi-dimensional reinforcement by incorporating braided layers that wrap around the rim structure. This adds dimensional stability and structural rigidity without significantly increasing weight, resolving the stiffness-deficiency problem.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Strength

If complex multi-layer fiber composite structures are used to improve performance, then stiffness-to-weight ratio is improved, but manufacturing cost and complexity increase

Engineering Contradiction:
Improvestiffness-to-weight ratioVSAvoidmanufacturing economy
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The complex performance requirements are divided into separate functional layers, each with a specific manufacturing process optimized for its purpose. This segmentation enables parallel production of different layers and simplifies quality control, reducing overall manufacturing complexity despite the multi-layer structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent optimizes fiber orientation angles, layer thicknesses, and material properties to achieve the desired stiffness-to-weight ratio. By carefully controlling these parameters within specific ranges, the design achieves high performance while maintaining manufacturability through standardized production parameters.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3290227B1Bicycle rim with filler yarns for supplementing surface layers of a reinforcing layer and bicycle with wheels using the rim
Publication Date: 2020.05.13 KROMKER REINHOLD
  • EP3290227B1 patent drawingFigure 1~5
  • EP3290227B1 patent drawingFigure 6~7

AI summary

The invention relates to a bicycle rim (1) for a bicycle wheel, comprising an annular body (4), wherein the body (4) is made of fiber composite material, and wherein the body (4) is composed of different layers (8, 9) of fibers, one layer (8) of fibers being formed as a cover layer (8) extending over the entire surface of the body (4), and wherein a circumferentially oriented reinforcing layer (11) is arranged at at least one selected, limited location of the cover layer (8), but extending around the entire circumference of the annular body (4) and within the body (4), i.e., covered by the cover layer (8). The invention also relates to a bicycle with a wheel in which a bicycle rim (1) according to the invention is used.