Automobile Knuckle Casting with Multi-Directional Gas Escape

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Solution Overview

Problem

Automobile knuckles struggle to effectively suppress vibration transmission from wheels to vehicle bodies due to warping and deformation, and the casting process often results in defects that reduce production efficiency.

Innovation Solution

A method for manufacturing an automobile knuckle with a cylindrical damper mounting portion, a bearing mounting portion, and a mounting arm portion that includes a low-rigidity area near the bearing mounting portion, allowing for efficient deformation and gas release during casting, thereby preventing defects and improving production efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If hollow portions are formed by cores supported through core prints, then weight reduction is achieved, but gas defects occur in corner portions with pocket shapes

Engineering Contradiction:
Improveweight of knuckleVSAvoidcasting quality
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The invention changes the dimensional configuration of the opening by extending it not only in the vertical direction but also in the width direction. This two-dimensional extension transforms the pocket-shaped corner into an open structure, allowing gas to escape during casting while maintaining the weight reduction benefit of hollow portions.

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

Solution Approach 2:

The opening is segmented into multiple directional extensions (vertical and width directions) rather than a single core print configuration. This segmentation allows different regions of the hollow portion to have optimized gas escape paths, preventing gas trapping in corner areas.

Inventive Principle:
Principle #1Segmentation

2Strength

If the knuckle structure is made rigid to maintain strength, then mechanical strength is improved, but vibration transmission to the vehicle body increases

Engineering Contradiction:
Improvemechanical strengthVSAvoidvibration transmission
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The invention applies different rigidity characteristics to different regions of the knuckle. The mounting arm portion is designed with lower rigidity to allow deformation and absorb vibration, while other critical areas maintain sufficient strength. This local differentiation of mechanical properties resolves the contradiction between overall strength and vibration suppression.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If a large opening is provided for gas escape, then casting quality is improved, but the opening may affect mechanical strength and vibration transmission

Engineering Contradiction:
Improvecasting qualityVSAvoidmechanical strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

Instead of enlarging the opening in a single direction which would compromise strength, the invention extends the opening in multiple directions (vertical and width directions). This multi-dimensional approach increases the effective opening area for gas escape while distributing the structural impact across different regions, minimizing the effect on overall mechanical strength.

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

Data Source

PatentEP3418157B1Automobile knuckle manufacturing method and automobile knuckle
Publication Date: 2021.06.02 MAZDA MOTOR CORP
  • EP3418157B1 patent drawingFigure 1
  • EP3418157B1 patent drawingFigure 2
  • EP3418157B1 patent drawingFigure 3

AI summary

The purpose of the present invention to provide a method for manufacturing a knuckle 50 capable of ensuring favorable castability with which the knuckle 50 capable of suppressing transmission of vibration from a front wheel 4 to a vehicle body is casted and, at the same time, production efficiency is improved, and to provide the knuckle 50. Provided is the method for manufacturing the knuckle 50 that includes a bearing mounting portion 51 on which a hub bearing 40 is mounted, a damper holding portion 541 which holds a damper 20, and a damper mounting arm portion 542 which couples the bearing mounting portion 51 and the damper holding portion 541, the method being such that by using one core 130 the knuckle 50 is integrally casted so as to formed therein a cylindrical opening S1 which is the inner space of the damper holding portion 541, a hollow opening S2 in which the inner space in a hollow portion 544 of the damper mounting arm portion 542, the hollow portion 544 extending in a closed cross section from the damper holding portion 541, is continuous with an opening formed in the damper holding portion 541, and an arm-portion opening S3 which is surrounded by a front arm portion 545 and a rear arm portion 546 of the damper mounting arm portion 542, extending from the hollow portion 544.