Air Spring Fork Stroke Detection via Dual Chamber Pressure Monitoring
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Solution Overview
Problem
Conventional front fork suspensions using air springs face challenges in accurately detecting stroke amounts and detecting air leaks due to low precision in pressure and temperature measurements, particularly because existing systems measure these parameters in only one spring chamber, leading to inadequate detection of anomalies in air tightness and pressure leaks between chambers.
Innovation Solution
The design incorporates a front fork with separate detectors for the outer and inner air spring chambers, along with a stroke detection compensator that compensates for temperature influences and detects pressure leaks, enabling precise stroke measurement and leak detection by measuring pressure and temperature in both chambers independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pressure and temperature are measured in only one spring chamber (outer air spring chamber), then the device complexity is reduced, but the measurement precision of stroke amount deteriorates
Solution Approach 1:
The air spring system is segmented into two independent measurement zones: the outer air spring chamber and the inner air spring chamber. Each chamber is equipped with its own pressure detector and temperature detector, allowing independent measurement of physical quantities in each segment. This segmentation enables precise stroke detection by comparing pressure changes in both chambers, while the modular detector configuration maintains manageable device complexity.
2Device complexity
If pressure and temperature are measured in only one spring chamber, then the device complexity is reduced, but the reliability of air leak detection deteriorates
Solution Approach 1:
The detection system is segmented into two independent monitoring subsystems: one for the outer air spring chamber and another for the inner air spring chamber. Each subsystem independently monitors pressure and temperature, enabling reliable detection of air leaks in either chamber. The segmented configuration allows the system to identify leaks in the outer chamber, inner chamber, or communication passages between them, maintaining high reliability while avoiding the complexity of a fully integrated monitoring system.
Solution Approach 2:
The system implements feedback mechanisms where pressure detectors continuously monitor pressure changes in both chambers and provide real-time data to the control unit. When pressure deviations exceed predetermined thresholds, the system generates leak detection signals, enabling immediate feedback on air tightness status. This feedback approach ensures reliable leak detection without requiring overly complex detection hardware.
3Device complexity
If a single set of pressure and temperature detectors is used, then the device complexity is reduced, but the reliability of stroke measurement deteriorates due to undetected detector malfunctions
Solution Approach 1:
The detection system extracts redundancy by providing alternative detection paths. If the pressure detector in one chamber malfunctions, the system can extract and utilize data from the other chamber's detector to continue stroke measurement. This extraction of backup capability from the dual-chamber configuration maintains measurement reliability without significantly increasing overall device complexity, as the detectors themselves are standard 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
This solution allows for accurate detection of stroke amounts and immediate identification of air leaks, enhancing the suspension's functionality and safety by improving precision and reliability in measuring the front fork's performance.
Implementation Method 1
focusing on the change in pressure of a gas M1 in a chamber M2 in accordance with an advance-retreat position of an operating member M3 in the chamber M2, the abovementioned pressure is detected by a pressure detector M4
Implementation Method 2
focusing on the influence that high temperature in the chamber M2 exerts on the abovementioned pressure, temperature detector M6 detects that temperature
Implementation Method 3
The air in the air spring chambers undergoes repeated compression and expansion as a result of the abovementioned volume increases or decreases. This compression and expansion of air translates into rises in the temperature in the air spring chambers, as well as rises in the pressure in the air spring chambers on account of the increases in temperature
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
Provided is a front fork in which a stroke amount of a spring leg that relies on an air spring can be detected precisely, and in which pressure leaks in the spring leg can be detected. The front fork has: a guide cylinder 11 that extends from one of a vehicle body-side tube 2B or an axle-side tube 2A that make up a spring leg 2; a piston 12 that is mounted to the leading end of a guide rod 17 that extends from the other one of the tubes; an inner air spring chamber 6 that is partitioned by the piston 12 in the interior of the guide cylinder 11; an outer air spring chamber 5 that is partitioned, outward of the inner air spring chamber 6, in the interior of the vehicle body-side tube 2B and the axle-side tube 2A; first detector 14 for detecting pressure and temperature in the outer air spring chamber 5; second detector 15 for detecting pressure and temperature in the inner air spring chamber 6; and stroke detection compensator 100 for detecting a stroke amount on the basis of the outputs of the first and second detector 14.