Die-Cast Wheel Hub With Through Holes for Weight Reduction

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Solution Overview

Problem

Die casting methods for manufacturing vehicle wheels result in increased mass and material costs due to difficulties in employing hollow structures and using different raw material properties, leading to higher manufacturing costs despite shorter cycle times.

Innovation Solution

A wheel design featuring an annular rim, hub, and spokes with strategically arranged connecting portions and through holes to reduce weight and material usage, allowing for die casting while maintaining structural integrity and ease of cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If die casting is used for wheel manufacture, then cycle time is shortened and productivity is improved, but the mass of the wheel increases and material cost rises

Engineering Contradiction:
Improvecycle timeVSAvoidmass of wheel
Core Design Contradiction:
ProductivityVSWeight of moving object

Solution Approach 1:

The hub is designed with through holes penetrating in the rotation axis line direction, creating a porous-like structure that reduces material usage and wheel mass while maintaining structural integrity through the connecting portions

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The hub's connecting portions are segmented into multiple discrete regions rather than being solid, allowing material removal through through holes while preserving necessary structural connections between inner and outer perimeter portions

Inventive Principle:
Principle #1Segmentation

2Productivity

If die casting is used for wheel manufacture, then cycle time is shortened, but material cost increases due to different raw material properties and larger material usage

Engineering Contradiction:
Improvecycle timeVSAvoidamount of metal material
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The through holes in the hub create a porous structure that significantly reduces the quantity of metal material required compared to solid hub designs, thereby lowering material cost despite using die casting process

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

Material is extracted from the hub by forming through holes that penetrate in the rotation axis line direction, removing unnecessary metal while maintaining essential structural functions

Inventive Principle:
Principle #2Taking out (Extraction)

3Weight of moving object

If a hollow structure is employed in die casting, then weight reduction is achieved, but using a core is difficult and manufacturing complexity increases

Engineering Contradiction:
Improvemass of wheelVSAvoiddifficulty of using core
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

Instead of using cores to create hollow structures, the invention extracts material by forming through holes in the hub, achieving weight reduction without the manufacturing complexity of core insertion in die casting

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than adding complexity through core usage to achieve hollow structures, the invention inverts the approach by removing material through through holes, simplifying the die casting process while achieving weight reduction

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3135573B1A wheel for straddled vehicles and a straddled vehicle
Publication Date: 2018.07.04 YAMAHA MOTOR CO LTD
  • EP3135573B1 patent drawingFigure 1
  • EP3135573B1 patent drawingFigure 2~3
  • EP3135573B1 patent drawingFigure 4

AI summary

A wheel for straddled vehicles according to an embodiment of the present invention is a die-cast product and includes a rim, a hub, and a plurality of spokes connecting the rim and the hub. The hub has a plurality of connecting portions connecting an inner perimeter portion and an outer perimeter portion, the plurality of connecting portions being arranged so as to radially extend from the inner perimeter portion to the outer perimeter portion and to be spaced away from one another in a circumferential direction. The plurality of connecting portions include a plurality of first connecting portions located on one side in a rotation axis line direction of the wheel and a plurality of second connecting portions located on the other side. When the hub is viewed from the rotation axis line direction, each of the plurality of first connecting portions is present between two second connecting portions adjoining each other in the circumferential direction, and each of the plurality of second connecting portions is present between two first connecting portions adjoining each other in the circumferential direction. A through hole penetrating in the rotation axis line direction is provided between a first connecting portion and a second connecting portion adjoining each other in the circumferential direction.