Trapezoidal Vehicle Spring Profile Bar Weight Reduction

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Solution Overview

Problem

Existing vehicle springs made from hot-formed flat bar steel are difficult to lighten while maintaining their resilient function and mechanical load-bearing capacity, as they require significant changes in geometry to reduce weight, which can compromise their performance under varying loads.

Innovation Solution

A method for producing vehicle springs by rolling a profile bar with material recesses on both narrow sides and the underside, resulting in a substantially trapezoidal cross-sectional shape with rounded corners, allowing for up to 30% weight reduction without impairing force absorption or springing effect, and enabling a more compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the geometry of the finished vehicle spring is changed to increase surface tension to make it more compact, then the weight is reduced, but the mechanical load-bearing capacity is impaired

Engineering Contradiction:
Improveweight of vehicle springVSAvoidmechanical load-bearing capacity
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The profile bar features material recesses at specific locations (narrow sides and underside) to create a trapezoidal cross-section, where material is selectively removed from non-critical areas while preserving material in load-bearing regions. This local modification reduces overall weight by up to 30% while maintaining the spring's mechanical load-bearing capacity and resilient function.

Inventive Principle:
Principle #3Local quality

2Weight of moving object

If the weight of the vehicle spring is reduced by changing geometry, then the compactness is improved, but the resilient function is compromised

Engineering Contradiction:
Improveweight of vehicle springVSAvoidresilient function
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The cross-sectional geometry parameters of the profile bar are changed from a conventional rectangular shape to a trapezoidal shape with material recesses. This parameter change optimizes the distribution of material, reducing weight while ensuring that the spring body maintains its inherent resilient function and springing effect under varying loads.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If a rectangular profile bar is used for manufacturing, then the manufacturing process is simple, but the weight reduction potential is limited

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidweight of vehicle spring
Core Design Contradiction:
Ease of manufactureVSWeight of moving object

Solution Approach 1:

The profile bar is pre-formed with material recesses creating a trapezoidal cross-section before the spring manufacturing process. This preliminary action integrates weight reduction into the starting material itself, allowing the spring to achieve up to 30% weight reduction without adding complex manufacturing steps to the spring production process.

Inventive Principle:
Principle #10Preliminary action

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 method effectively reduces the weight of vehicle springs by optimizing the geometry of the starting material, ensuring the resilient function and mechanical load-bearing capacity are maintained, while allowing for a more compact design without compromising performance.

Implementation Method 1

Vehicle springs within the scope of the invention are hot-formed, in particular rolled, from flat bar steel, preferably spring steel, at temperatures of approximately 800 to 1200° C.

Methodology Applied
Scientific EffectHot-forming: Heat Treatment

Data Source

PatentEP3719341B1Sectional bar and vehicle spring made therefrom
Publication Date: 2022.05.04 HENDRICKSON COMML VEHICLE SYST EURO GMBH
  • EP3719341B1 patent drawingFigure 1~4
  • EP3719341B1 patent drawingFigure 5~11

AI summary

An elongated spring body (20) of a vehicle spring is rolled from a profile bar (1), wherein the spring body (20) has at least one material recess (6), the cross-sectional shape of the spring body (20) changing along its length and the width (B) of the material recess (6) changing along the length of the material recess (6). The spring body (20) has a material recess (6) on both narrow sides (4, 5) and on the underside (3), so that it has a substantially trapezoidal cross-sectional shape with rounded corners along its length.