Gas Spring Distance Sensing With Ultrasonic Reflector Alignment
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Solution Overview
Problem
Existing systems for determining the axial distance between the end members of a gas pressure spring in vehicles are prone to inaccuracies due to lateral offsets and environmental exposure, leading to unreliable measurements.
Innovation Solution
A device with a distance sensor integrated into the vehicle's chassis-side end member, utilizing a metallic support body with an elastomer damping layer and a metal support ring, ensures precise measurement by maintaining constant alignment and using air-guiding means to keep the sensor surface clean.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ultrasonic sensor is arranged inside the gas spring to measure axial distance, then the measurement is protected from environmental exposure, but lateral offset between end members causes misalignment between transmitter and receiver
Solution Approach 1:
A reflector is introduced as an intermediary element to facilitate ultrasonic measurement. The reflector is attached to the moving end member and reflects the ultrasonic pulse back to the receiver, enabling indirect measurement that compensates for lateral offsets between the fixed transmitter and moving receiver components
Solution Approach 2:
The measurement system transitions from direct line-of-sight transmission between transmitter and receiver to a reflected path that utilizes the reflector surface. This dimensional change in the signal path allows measurement despite lateral misalignment, as the reflector redirects the ultrasonic wave back to the receiver
2Measurement precision
If the ultrasonic transmitter emits a wide beam shape to accommodate lateral offset, then alignment tolerance is improved, but reflections at various points on the gas spring distort the measurement result
Solution Approach 1:
Instead of using a wide beam that causes scattered reflections, the system employs a focused ultrasonic beam that targets specifically at the reflector. This localized energy concentration ensures that only the intended reflector surface returns the signal, eliminating spurious reflections from other gas spring surfaces while maintaining alignment tolerance through the reflector's strategic positioning
3Ease of operation
If a mechanical actuating arm is used to control the valve, then the valve can be actuated by relative movement between sprung and unsprung parts, but the actuating arm has complex construction and is exposed to road grime and corrosive substances
Solution Approach 1:
The mechanical actuating arm system is replaced with an ultrasonic measurement system that electronically determines axial distance. This substitution eliminates the complex mechanical linkage exposed to environmental factors, using instead non-contact ultrasonic waves to measure position and control the valve through electronic signals
Solution Approach 2:
The ultrasonic wave serves as an intermediary that transmits measurement information without requiring physical contact or mechanical transmission. This allows the system to determine axial distance and control the valve without exposing mechanical components to road grime and corrosive substances
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 solution provides more reliable and precise measurement of the axial distance between the end members, maintaining accuracy even with lateral movements and preventing contamination, thus enhancing operational reliability.
Implementation Method 1
The ultrasonic transmitter transmits an ultrasonic pulse to the reflector
Implementation Method 2
the reflector reflects it back to the ultrasonic receiver
Implementation Method 3
a damping layer made of an elastomer is fastened to the radial outer side of the support body
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a device (1.1, 1.2) for determining the axial distance (A) between two end members (4, 6) of a gas spring (2), which are arranged to be movable relative to each other in the axial direction of the gas spring (2), wherein the two end members (4, 6) are directly or indirectly connected to a flexible bellows (8) which defines an interior space (30) of the gas spring (2), wherein a distance sensor (10) is arranged on one of the two end members, with the aid of which the axial distance (A) between the two end members (4, 6) can be determined, wherein a metallic support body (12) is attached to the chassis-side end member (6), a damping layer (14) made of an elastomer is attached to the radial outer side of the support body, and a metallic support ring (16) is attached to the radial outer side of the damping layer (14), against which the chassis-side end of the bellows (8) is attached both axially and also provides radial support.To improve the measuring capability and the measuring accuracy, it is provided that the distance sensor (10) is arranged in the area of the body-side upper end of the metallic support body (12) with a view of the underside of the upper end member (4).