Helically Wound Jounce Bumper Contact Surface

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Solution Overview

Problem

Existing spring elements for vehicle shock absorbers face challenges in achieving soft initial deformation while maintaining progressive stiffness as they deform, which affects the vehicle's suspension comfort and safety.

Innovation Solution

A spring element with a helically wound contact surface, where only a portion initially contacts the damper cap, reducing initial resistance and progressively increasing stiffness as more of the surface engages, enhancing the deformation response and dampening characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the entire circumference of the end portion contacts the damper cap, then the initial resistance to deformation is high, but the progressive stiffness with increasing deformation is reduced

Engineering Contradiction:
Improveinitial resistance to deformationVSAvoidprogressive stiffness
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The contact surface is segmented into different zones with varying contact radii. The first contact zone has a smaller contact radius than the second contact zone, creating a progressive engagement pattern where only part of the end portion initially contacts the damper cap, reducing initial resistance while maintaining progressive stiffness capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the end portion are given different local properties through the helical winding pattern. The contact surface varies locally in its engagement characteristics, with the first contact zone providing initial soft contact and the second contact zone providing progressive stiffness as deformation increases

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the contact surface is flat and uniform, then the manufacturing is simple, but the deformation response is asymmetric and impacts are not mitigated

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddeformation symmetry
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The contact surface is designed with a helical winding pattern that introduces curvature and asymmetry into the otherwise cylindrical end portion. This helical geometry transforms the flat contact surface into a three-dimensional curved surface that progressively engages with the damper cap, mitigating asymmetrical force impacts while remaining manufacturable

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 helically wound contact surface design allows for smooth progressive stiffness increase, improving the vehicle's suspension comfort and safety by mitigating asymmetrical force impacts and enhancing dampening performance.

Implementation Method 1

the base body being elastically deformable between an uncompressed basic state and a compressed state in which the base body is at least partially compressed in the direction of the longitudinal axis

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the spring element is compressed from an uncompressed basic state along its longitudinal axis into an at least partially compressed state, thereby dissipating energy by deforming

Methodology Applied
Scientific EffectEnergy dissipation: Damping

Data Source

PatentEP3969779B1Spring element, in particular jounce bumper, for a vehicle shock absorber
Publication Date: 2023.08.02 BASF POLYURETHANES
  • EP3969779B1 patent drawingFigure 1
  • EP3969779B1 patent drawingFigure 2
  • EP3969779B1 patent drawingFigure 3

AI summary

The invention comprises to a spring element (1), in particular jounce bumper, for a vehicle shock absorber, comprising: a longitudinal axis (L) and a base body (3) having a length (t) along the longitudinal axis (L), the base body (3) being elastically deformable between an uncompressed basic state and a compressed state in which the base body (3) is at least partially compressed in the direction of the longitudinal axis (L), an end portion (5) configured for contact against a damper cap of the vehicle shock absorber; wherein the end portion (5) comprises a contact surface (7) that is wound along a helix around the longitudinal axis (L).