Segmented Leaf Spring Element for Commercial Vehicle Suspension

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Solution Overview

Problem

Existing suspension systems for commercial vehicles, such as leaf springs and coil springs, face challenges in providing adequate suspension comfort, driving safety, and space efficiency, with high production costs and weight affecting vehicle dynamics.

Innovation Solution

A leaf spring element comprising multiple leaf spring sections with moment-fixed end regions and S-shaped or articulated designs, allowing for parallel displacement and deformation under load, reducing overall height and increasing spring deflection while maintaining low installation space and production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional leaf springs are used for commercial vehicle suspension, then manufacturing cost is low and structural simplicity is maintained, but ride comfort is limited and driving safety is restricted

Engineering Contradiction:
Improvemanufacturing costVSAvoidride comfort and driving safety
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The leaf spring is divided into multiple leaf spring sections (first, second, and third sections) with different curvature radii and thicknesses. Each section is optimized independently to handle specific load conditions, allowing the spring to provide progressive suspension characteristics that improve ride comfort and driving safety while maintaining manufacturing simplicity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the leaf spring are given different local properties: the first section has a smaller curvature radius and greater thickness for initial load absorption, the second section has intermediate properties, and the third section has a larger curvature radius and lesser thickness for progressive engagement. This local differentiation enables improved suspension performance without requiring complete redesign of the entire spring

Inventive Principle:
Principle #3Local quality

2Reliability

If coil springs are used for suspension in passenger cars to improve ride comfort, then spring characteristics can be adapted to specific requirements, but manufacturing effort and cost are considerably higher

Engineering Contradiction:
Improveride comfortVSAvoidmanufacturing effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The leaf spring assembly is segmented into multiple sections with varying geometric parameters, allowing customization of spring characteristics through configuration rather than manufacturing complexity. Each section can be independently designed to achieve desired force-deflection characteristics without requiring custom manufacturing processes for each vehicle type

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs composite construction with leaves of varying lengths and pre-tensions joined together by spring clamps, creating a multi-layered system that achieves customized spring characteristics through material arrangement and geometric configuration rather than through complex manufacturing processes

Inventive Principle:
Principle #40Composite materials

3Reliability

If coil springs are used to provide adequate suspension performance, then spring characteristics can be customized, but spring weight is comparatively high negatively impacting vehicle dynamics

Engineering Contradiction:
Improvesuspension performanceVSAvoidspring weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The leaf spring is segmented into multiple sections with optimized thicknesses and curvature radii, allowing the structure to use material only where needed for load bearing. This segmentation enables weight reduction by eliminating excess material in low-stress regions while maintaining suspension performance through the progressive engagement of different sections

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent optimizes geometric parameters including curvature radii, thicknesses, and lengths of individual leaf sections to achieve the desired spring characteristics with minimum material. By varying these parameters across different sections, the design achieves adequate suspension performance with reduced overall weight compared to uniform coil spring designs

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If arc-shaped spring force sections are arranged directly above one another to determine spring height, then spring characteristic can be adjusted, but overall height becomes considerable affecting installation space

Engineering Contradiction:
Improvespring characteristicVSAvoidoverall height
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

Instead of arranging spring force sections vertically one above another, the patent distributes them horizontally along the length of the leaf spring in sequential sections. This dimensional reorganization allows the spring to achieve its force-deflection characteristics through longitudinal progression rather than vertical stacking, significantly reducing the overall height while maintaining adaptability of spring characteristics through section configuration

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

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 solution provides improved suspension comfort and safety with reduced weight and installation space, enabling adaptable spring characteristics and extended service life through modular design and fiber composite materials, enhancing vehicle dynamics and cost-effectiveness.

Implementation Method 1

the respective end regions of the at least one leaf spring section are parallel displaceable and deflectable relative to each other in a force application direction

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2472137B1Leaf spring element and leaf spring assembly
Publication Date: 2019.10.30 KS KOLBENSCHMIDT GMBH
  • EP2472137B1 patent drawingFigure 1a~1b
  • EP2472137B1 patent drawingFigure 2a~2b
  • EP2472137B1 patent drawingFigure 3a~3c

AI summary

The element (1'') has two leaf spring sections including respective end regions mounted in a bearing device in torque-fixed manner. Other end regions of one of the leaf spring sections and a third leaf spring section are mounted in another bearing device in torque-fixed manner. The end regions of the sections are aligned parallel to each other in an unloaded condition of the element. The end regions are displaced in parallel and deflected relative to each other by force application. The two leaf spring sections are actively connected with each other by eight S-shaped leaf spring sections (13).