Straddled Vehicle Wheel Rim Thickness Gradient for Weight and Strength

Solution Overview

Problem

Wheels for straddled vehicles face a challenge in achieving weight reduction while maintaining necessary strength, which is essential for improving dynamic performance and fuel economy.

Innovation Solution

The wheel design incorporates a thickness-inflating structure in the rim, where the rim wall thickness increases from the ends to the center of the inter-spoke sections, providing increased section modulus and reducing strength differences between spoke and center areas, allowing for weight reduction while maintaining strength and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the rim wall thickness is reduced to decrease wheel weight, then weight reduction is achieved, but the strength and stability of the wheel deteriorates

Engineering Contradiction:

Improvewheel weightVSAvoidrim strength

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The rim wall thickness is designed to vary locally along the inter-spoke section, being thinner at the ends near spokes and thicker at the center. This local quality variation allows weight reduction in critical areas while maintaining strength where needed, resolving the contradiction between weight reduction and strength maintenance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of uniformly reducing rim thickness in one dimension, the invention varies the thickness along the circumferential direction (another dimension), creating a gradient structure that optimizes both weight and strength by distributing material where it is most effective.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Weight of moving object

If the rim wall thickness is uniformly reduced, then weight reduction is achieved, but the strength difference between spoke and center areas increases

Engineering Contradiction:

Improvewheel weightVSAvoidstrength uniformity

Core Design Contradiction:

Weight of moving objectVSStability of the object's composition

Solution Approach 1:

The rim wall thickness is designed to vary locally along the inter-spoke section, being thinner at the ends near spokes and thicker at the center. This local quality variation allows weight reduction in critical areas while maintaining strength where needed, resolving the contradiction between weight reduction and strength maintenance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of uniformly reducing rim thickness in one dimension, the invention varies the thickness along the circumferential direction (another dimension), creating a gradient structure that optimizes both weight and strength by distributing material where it is most effective.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3957492B1Wheel for straddled vehicles, and straddled vehicle

Publication Date: 2023.04.12 YAMAHA MOTOR CO LTD

Figure 1
Figure 2~3
Figure 4

AI summary

A wheel for straddled vehicles (100) includes: a hub (10) through which a wheel shaft is to be inserted; an annular rim (20); and a plurality of spokes (30) connecting the hub and the rim. The rim includes a plurality of inter-spoke sections (21) each located between an adjoining pair of spokes among the plurality of spokes. In at least one inter-spoke section among the plurality of inter-spoke sections, the thickness of the rim at a midpoint on the wheel axis direction increases across an entire stretch from opposite ends of the inter-spoke section to a substantial center of the inter-spoke section.