Twist Beam Bulged Middle Section Roll Stiffness

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Solution Overview

Problem

Existing twist beams for automotive vehicles face challenges in achieving optimal roll stiffness while minimizing weight and manufacturing complexity, as increasing thickness for better roll stiffness also increases weight and costs, and complex manufacturing processes are required for closed cross-section designs or stabilizer bars.

Innovation Solution

A twist beam with a bulged middle section, featuring increased width and height, providing a greater cross-sectional area to enhance roll stiffness without the need for stabilizer bars or complex manufacturing, while maintaining a lightweight design through strategic tuning of dimensions and manufacturing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the thickness of the twist beam is increased to improve roll stiffness, then the roll stiffness is improved, but the weight and manufacturing costs increase

Engineering Contradiction:
Improveroll stiffnessVSAvoidweight of twist beam
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The twist beam features a bulged middle section with increased cross-sectional area specifically located where roll stiffness is needed, while the end sections maintain smaller dimensions. This local variation in geometry provides enhanced roll stiffness in the critical middle region without increasing the weight of the entire beam, resolving the contradiction between overall strength improvement and weight minimization.

Inventive Principle:
Principle #3Local quality

2Strength

If a closed cross-section or stabilizer bar is used to achieve adequate roll stiffness, then the roll stiffness is improved, but the manufacturing complexity and costs increase

Engineering Contradiction:
Improveroll stiffnessVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention changes the geometric parameters of the twist beam by introducing a bulged middle section with increased width and height. This parameter modification achieves the desired roll stiffness through dimensional variation rather than through complex structural configurations like closed sections or stabilizer bars, thereby maintaining manufacturing simplicity while improving performance.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The twist beam achieves exceptional roll stiffness with reduced weight and simplified manufacturing, outperforming comparable designs in terms of weight reduction and roll stiffness, as demonstrated by test results showing a balance of weight and roll stiffness performance.

Implementation Method 1

The twist beam provides the roll stiffness by twisting as the trailing arms move vertically relative to one another

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2969611B1Rear twist beam with bulged middle section
Publication Date: 2019.03.27 MAGNA INTERNATIONAL INC
  • EP2969611B1 patent drawingFigure 1A
  • EP2969611B1 patent drawingFigure 1B
  • EP2969611B1 patent drawingFigure 2A

AI summary

A twist beam (22) for a suspension assembly (20) comprises a base portion (44) and side walls (46) presenting an open U-shaped cross-section and a bulged middle section (24). The twist beam (22) includes end sections (56, 58), the middle section (24), and transition sections (60, 62) each extending from one of the end sections (56, 58) to the middle section (24). The width (w) and the height (h) of the twist beam (22) increase along the transition sections (60, 62) to the middle section (24). The width (w) and the height (h) of the middle section (24) are greater than the width (w) and the height (h) of the end sections (56, 58). The cross-sectional area of the bulged middle section (24) is typically 10% to 30% greater than the cross-sectional area of the end sections (56, 58).