Hydraulic Shock Absorber Stuck Valve Detection and Passive Mode Switch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydraulic shock absorbers for railway vehicles fail to detect when the damping force generation mechanism is stuck at the soft side, leading to reduced ride comfort and stability due to inadequate damping force generation during hard characteristic requirements.
Innovation Solution
A hydraulic shock absorber with a control unit that includes a vibration detection unit and a damping force adjustment unit, which adjusts solenoid control currents to determine if the damping force generation mechanisms are stuck at the soft side, and switches to a passive mode to generate damping forces via a bypass passage and passive valve when stuck, ensuring continued stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the extension-side damping force generation mechanism or compression-side damping force generation mechanism is stuck at the soft side, then the damping force cannot be adjusted to the hard side, but the control system cannot detect the failure and continues to operate in semi-active mode
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the actual damping force generated by the damping force generation mechanisms and compares it with the commanded damping force. When a discrepancy is detected (indicating the mechanism is stuck at the soft side), the control unit switches to passive mode to ensure continued operational reliability. This feedback loop enables automatic failure detection and mode switching without adding complex diagnostic hardware.
2Reliability
If the control system switches to passive mode to bypass the stuck solenoid, then damping force generation is maintained, but the semi-active control functionality is lost
Solution Approach 1:
The patent prepares for potential solenoid failure by designing a passive damping mode that is always available but normally bypassed. The bypass passage and passive valve are pre-configured to take over damping force generation if the active solenoid-controlled mechanisms fail. This prior cushioning ensures that even though semi-active control versatility is lost in failure mode, the basic damping function remains reliable and the system degrades gracefully rather than completely failing.
3Measurement precision
If the control unit continuously monitors vibration to detect stuck mechanisms, then failure detection accuracy is improved, but energy consumption and processing load increase
Solution Approach 1:
The patent monitors vibration parameters (amplitude, frequency, duration) and compares them against predetermined thresholds to detect stuck mechanisms. By changing the monitoring approach from continuous high-frequency sampling to event-triggered monitoring based on vibration threshold exceedance, the system maintains high detection accuracy while significantly reducing the average energy consumption and processing load of the control unit.
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 solution enables the hydraulic shock absorber to maintain ride comfort and stability by detecting stuck damping force generation mechanisms and switching to a passive mode, allowing for effective damping force generation even when the solenoids are stuck at the soft side.
Implementation Method 1
a vibration detection unit configured to detect a vibration transmitted to one of the members
Implementation Method 2
an extension-side damping force generation mechanism configured to adjust an extension-side damping force by controlling a flow of the hydraulic fluid and configured to be driven by a solenoid
Implementation Method 3
configured to be driven by a solenoid
Implementation Method 4
a cylinder sealingly containing hydraulic fluid
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present invention provides a hydraulic shock absorber capable of detecting that a damping force generation mechanism is stuck at a soft characteristic. When a state having abnormality is maintained for a certain time period with the proportional solenoid valves 26 and 27 fixed at a hard side, a controller determines that the proportional solenoid valve 26 or the proportional solenoid valve 27 is stuck at a soft side, and switches a control mode from a failure mode to a passive mode. As a result, even when the proportional solenoid valve 26 or the proportional solenoid valve 27 is stuck at the soft side, it is possible to secure a ride comfort and running stability of a vehicle.