Air Spring Reflector Geometry for Reliable Ultrasonic Echo

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Solution Overview

Problem

Existing air spring distance measurement systems face challenges in ensuring reliable and strong sound wave reflection due to non-orthogonal angles between the sound beam and reflecting plane, leading to disrupted distance measurements and potential damage from bump impacts, especially in commercial vehicle applications.

Innovation Solution

The reflector component features a ring-shaped surface composed of truncated cone sectors aligned radially, with vertices touching a common plane, ensuring consistent sound reflection and acting as a stop buffer to prevent plastic deformation during impacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flat reflective surface is used in air spring distance measurement, then the structure is simple, but the sound wave reflection is unreliable when the sound beam and reflecting plane are non-orthogonal

Engineering Contradiction:
Improvestructural simplicityVSAvoidsound wave reflection reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The reflective surface is segmented into multiple inclined reflective facets arranged in a circular pattern. Each facet is inclined at a specific angle to reflect sound waves back toward the transducer. This segmentation allows the surface to maintain simplicity in construction while achieving reliable sound wave reflection across various angular positions of the air spring piston.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the reflective surface have different local orientations (inclined facets at various angles) to optimize sound wave reflection for specific angular positions. This local variation in surface quality ensures that regardless of the air spring's kinematic state, at least one facet will be properly oriented to reflect sound waves back to the transducer, solving the reliability issue while keeping the overall structure simple.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If punctiform bumps are used on the reflective surface, then sound waves are scattered in many directions, but the reflected power is low and the bumps are vulnerable to damage from buffer impacts

Engineering Contradiction:
Improvesound wave scattering capabilityVSAvoidbump durability against impact
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

Instead of using small punctiform bumps, the invention employs inclined reflective facets with larger surface areas. These facets are oriented at specific angles to reflect sound waves effectively. The curved or inclined surfaces provide the necessary sound wave scattering and reflection capabilities while having sufficient structural strength to withstand buffer impacts without damage.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If the reflective surface is adapted to each individual air spring type, then the sound reflection is optimized for specific kinematic conditions, but the manufacturing effort and complexity increase significantly

Engineering Contradiction:
Improvesound reflection optimizationVSAvoidmanufacturing adaptation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The reflective surface design with multiple inclined facets arranged in a circular pattern creates a universal solution that works across different kinematic conditions and air spring types. The circular arrangement of facets ensures that regardless of the angular position or specific application, at least one facet will be properly oriented to reflect sound waves back to the transducer. This universal design eliminates the need for custom adaptation to each air spring type while maintaining optimized sound reflection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If a convex buffer shape is used to ensure strong echo radiation, then the echo signal is sufficient in all kinematic situations, but the buffer shape must be adapted to each air spring type requiring significant effort

Engineering Contradiction:
Improveecho signal sufficiencyVSAvoidbuffer shape adaptation effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The buffer's reflective surface is segmented into multiple inclined facets arranged in a circular pattern. This segmentation allows the buffer to maintain a standard convex shape that works universally across different air spring types, while the inclined facets ensure sufficient echo radiation in all kinematic situations. The segmented design eliminates the need for custom shape adaptation to each air spring type.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The circular arrangement of inclined reflective facets creates a universal buffer design that provides sufficient echo radiation across all kinematic conditions and air spring types. This universal geometry eliminates the need for individual adaptation to each air spring model, significantly reducing manufacturing effort while maintaining reliable distance measurement functionality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This design ensures reliable sound wave reflection in all kinematic conditions, simplifies assembly, and prevents damage by maintaining a consistent reflection edge and using materials suitable for various air spring types.

Implementation Method 1

A sound transducer 100 generates a sound lobe 200

Methodology Applied
Scientific EffectUltrasonic sound wave generation: Ultrasound

Implementation Method 2

there is a reflection 300 of the sound lobe 200 on a baffle plate 400

Methodology Applied
Scientific EffectSound wave reflection: Reflection

Implementation Method 3

the device for non-contact distance measurement using the pulse-echo method

Methodology Applied
Scientific EffectTime of flight measurement: Time of Flight

Data Source

PatentEP4019303B1Air spring
Publication Date: 2023.08.23 CONTITECH LUFTEDERSYSTEME GMBH
  • EP4019303B1 patent drawingFigure 1
  • EP4019303B1 patent drawingFigure 2~3
  • EP4019303B1 patent drawingFigure 4

AI summary

The invention relates to a device (1) for non-contact distance measurement within an air spring of a motor vehicle using the impulse-echo method. The invention was based on the objective of improving the device in such a way that a reliable reflection (15) of the sound waves (14) to the transducer, as strong as possible for evaluating the distance measurement, is provided under every kinematic condition of the air spring, and the device is also suitable for the requirements when the end stop (16) is in contact with the air spring.This task is solved by the reflector component having a reflective surface (2) made of back-reflecting bodies (3) in the form of ring-shaped, touching, approximately longitudinally bisected truncated cones (3), wherein the reflecting bodies thus formed are also referred to as truncated cone sectors and the truncated cone sectors (3) are radially oriented and have a conicity such that the vertices (6) of all truncated cone sectors (3) projecting from the reflective surface (2) are tangent to an imaginary common plane and intersect in such a way that the sector angles (11, 12) formed by the individual truncated cone sectors (3) are always less than 180°.