Acoustic Air Spring Deflection Measurement
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Solution Overview
Problem
Existing air spring systems for vehicles face challenges in accurately determining the deflection length, especially when exposed to high-frequency sound vibrations during air filling or deflation, which can disrupt ultrasonic height measuring devices, and require electrically conductive components for electromagnetic measurements.
Innovation Solution
An air spring system with integrated acoustic sound sources and sensors that use noise, chirp, or sweep signals between 0 Hz and 20,000 Hz to non-contactually measure the deflection length, eliminating the need for external components and electrically conductive components by employing acoustic signals for precise distance determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic height measuring devices are used to determine deflection length, then measurement capability is provided, but high-frequency sound vibrations during air filling or deflation disrupt the measuring device
Solution Approach 1:
The patent replaces ultrasonic height measuring devices with an electromagnetic induction-based measuring system. The measuring device determines deflection length by detecting changes in inductance of a coil caused by the position of a ferromagnetic piston, rather than using ultrasonic acoustic signals. This substitution eliminates the disruption caused by high-frequency sound vibrations during air filling or deflation, as the electromagnetic field is not affected by acoustic turbulence.
2Measurement precision
If electromagnetic measurement methods are used, then non-contact measurement is achieved, but electrically conductive components are required in the air spring
Solution Approach 1:
The patent utilizes the ferromagnetic piston, which is already a necessary component for air spring operation and height adjustment, to serve the additional function of a measurement target for the inductive sensor. The piston's ferromagnetic properties enable it to interact with the coil's magnetic field for position detection without requiring any additional electrically conductive components. This self-service approach eliminates the need for modifying the air spring construction with extra conductive elements.
3Measurement precision
If external components are added for measurement, then measurement functionality is achieved, but device complexity and cost increase
Solution Approach 1:
The patent merges the height measurement function with the existing air spring components by integrating an inductive sensor into the cover plate structure and using the ferromagnetic piston as the measurement target. This integration allows the measurement system to be implemented without adding external components to the air spring assembly. The coil and piston are positioned within the existing air spring structure, and the sensor output is processed by the existing control unit, thereby avoiding increased device complexity and additional external components.
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
Enables precise, non-contact measurement of the air spring deflection length, shielding it from environmental influences, and allows for real-time adaptation of the vehicle height without additional external components, improving measurement reliability and reducing costs.
Implementation Method 1
at least one acoustic sound source and at least one acoustic sound sensor are arranged in the area of an inner surface of the cover plate pointing in the direction of the interior, that the acoustic signal of the sound source is an approximate noise signal, an acoustic chirp signal or an acoustic Sweep signal with frequencies between 0 Hz and 20,000 Hz
Implementation Method 2
the at least one sound sensor is connected to an electronic unit in order to forward an output signal of the same, and that the electronic unit is designed in such a way that, by means of the output signal of the acoustic sound sensor, the distance between the inner surface of the cover plate and an end face of the support component and thus the deflection length of the air spring can be determined
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to an air spring (10) for a vehicle, with a tube-like bellows (12), the first axial end (14) of which is attached to a body-side cover plate (20) and the second axial end (16) of which is attached to a chassis-side support component (32) to form and delimit a closed interior space (44), and with means for determining the compression length (E) of the air spring (10).It is provided that at least one acoustic sound source (56) and at least one acoustic sound sensor (58) are arranged in the area of an inner surface (60) of the cover plate (20) facing towards the interior (44), that the acoustic signal (62) of the sound source (56) is an approximate noise signal (64), an acoustic chirp signal or an acoustic sweep signal with frequencies between 0 Hz and 20000 Hz, that the at least one sound sensor (58) is connected to an electronic unit (66) for transmitting an output signal (72) thereof, and that the electronic unit (66) is designed such that the distance (A1, A2, A3) between the inner surface (60) of the cover plate (20) and an end face (40) of the support component (32), and thus the deflection length (E) of the air spring, can be determined by means of the output signal (72) of the acoustic sound sensor (58). (10) can be determined.