U-Shaped Suspension Spring Link for Stiffness and Fatigue Life

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Solution Overview

Problem

Existing spring links for vehicle suspensions face challenges in achieving a balance between sufficient stiffness, fatigue resistance, and reasonable weight, while maintaining simplicity in fabrication, as previous designs often compromise on these factors.

Innovation Solution

The spring link design incorporates a specific topological structure in the bottom area with defined topological quantities and imprints to enhance load distribution and fatigue resistance, using a cylindrical section with orthogonal axis and controlled cylinder diameter, combined with a spring pad for improved stiffness and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the spring link uses a closed profile with top side reinforcement, then stiffness is improved, but weight increases and fabrication complexity increases

Engineering Contradiction:
ImprovestiffnessVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent removes the top side of the closed profile entirely, extracting only the essential U-shaped structure (bottom and side walls) needed for functionality. This eliminates unnecessary material in the top region while maintaining sufficient stiffness through optimized side wall geometry and spring seat design.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different structural characteristics to different regions: the side walls feature outwardly bent top portions and flanges for stiffness, the spring seat has specific geometric features for load distribution, while the bottom remains relatively simple. This localized optimization achieves required strength without uniform material distribution that would increase overall weight.

Inventive Principle:
Principle #3Local quality

2Strength

If the spring link uses a U-shaped profile with outwardly bent side walls, then stiffness is improved, but fatigue resistance deteriorates

Engineering Contradiction:
ImprovestiffnessVSAvoidfatigue resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces sharp corners and abrupt transitions with curved geometries. The side walls feature outwardly bent top portions with smooth transitions, and the spring seat incorporates curved surfaces. These rounded features eliminate stress concentration points that would initiate fatigue cracks, while maintaining the required stiffness through the curved structural form.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Strength

If the spring link uses additional reinforcing elements, then stiffness is improved, but device complexity increases

Engineering Contradiction:
ImprovestiffnessVSAvoidstructural complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent integrates multiple functions into the side walls themselves rather than adding separate reinforcing elements. The outwardly bent top portions and flanges of the side walls provide both structural support and stiffness enhancement in a unified structure, eliminating the need for additional discrete reinforcing components.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If the spring seat is placed on the bottom side, then freedom in spring/damping device selection is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvespring/damping device selection freedomVSAvoidspring seat positioning precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The spring seat is pre-formed as an integrated feature of the U-shaped profile during the primary manufacturing process, with predetermined geometry and positioning. The bottom surface includes the spring seat with specific dimensional features built-in, eliminating the need for subsequent precision machining or assembly operations to establish the spring mounting location.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3939810B1Spring link for a vehicle suspension
Publication Date: 2025.10.15 NEUMAN RAUFOSS DEV AS
  • EP3939810B1 patent drawingFigure 1a~1b
  • EP3939810B1 patent drawingFigure 1c~1f
  • EP3939810B1 patent drawingFigure 2a~2b

AI summary

Spring link for a vehicle suspension, comprising: an elongated base body extending along an axial direction and having an essentially U-shaped cross section and an areal bottom extending along an axial-transversal xy-plane, a wheel-side mounting portion and a vehicle-side mounting portion at respective axial end portions of the base body, and a spring seat for spring/damping means defined at a transversely outwardly bulged middle portion of the base body, wherein a topological quantity defined by the number of segments of a path providing change of sign of curvature is at least two, preferably at least four, said path being defined by a cylindrical section of the bottom with corresponding cylinder axis being orthogonal to the xy-plane and going through the center of the spring seat and corresponding cylinder diameter being at least half of the transversal bottom width at said center.