Rail Vehicle Body Position Compensation via Intermediary Sensing
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Solution Overview
Problem
Current systems for railway vehicles fail to effectively compensate for both primary and secondary suspension deflections in response to changing passenger loads, leading to misalignment of the vehicle body with respect to a datum line, such as a station platform, which is crucial for safe and efficient operation and compliance with accessibility standards.
Innovation Solution
A compensating device that includes a chamber and piston in fluid communication with the secondary suspension, with valves and an actuating mechanism to control the flow of pressurized fluid, allowing for proportional motion to account for both primary and secondary suspension deflections, maintaining the vehicle body's vertical position relative to a datum line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the leveling valve is mounted between the truck frame and truck bolster to control secondary suspension height, then the air spring height can be maintained constant, but the device cannot compensate for primary suspension deflection
Solution Approach 1:
A sensing arm acts as an intermediary mechanism that transfers the vertical position information from the car body to the leveling valve. The sensing arm is connected to the car body at one end and to the leveling valve at the other end, enabling the valve to sense car body height changes and adjust air spring pressure accordingly, thereby achieving compensation for both primary and secondary suspension deflections.
Solution Approach 2:
The leveling valve system is enhanced to perform multiple functions: it not only controls the secondary suspension air spring height but also compensates for primary suspension deflection. This is achieved by mounting the leveling valve on the truck bolster and connecting its sensing arm to the car body, allowing it to sense and compensate for height changes from both suspension levels.
2Manufacturing precision
If the sensing arm is connected to elements below the primary suspension to achieve both primary and secondary suspension compensation, then complete deflection compensation can be obtained, but mechanical issues from truck rotation and high shock levels make implementation difficult
Solution Approach 1:
The sensing arm serves as an intermediary that transmits the vertical position signal from the car body to the leveling valve without requiring direct connection to elements below the primary suspension. This intermediary mechanism achieves complete suspension compensation while avoiding the mechanical issues of high shock and vibration environments below the primary suspension.
Solution Approach 2:
The sensing arm is positioned and oriented in a specific dimensional arrangement - extending from the car body downward to connect with the leveling valve on the truck bolster. This spatial arrangement allows the sensing arm to effectively transmit vertical position information while being positioned in a location that avoids the most severe mechanical stress zones, facilitating easier implementation.
3Reliability
If only secondary suspension deflection is compensated for, then the leveling valve can maintain air spring height, but the vehicle body misaligns with the datum line due to primary suspension deflection
Solution Approach 1:
The leveling valve system is configured to perform dual compensation functions: it maintains air spring height by controlling secondary suspension while simultaneously compensating for primary suspension deflection. This is achieved by mounting the valve on the truck bolster and connecting its sensing arm to the car body, enabling it to sense and correct height changes from both suspension levels, thereby maintaining both air spring stability and vehicle body alignment with the datum line.
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 device ensures the vehicle body remains aligned with the platform by compensating for both primary and secondary suspension deflections, enhancing safety, efficiency, and compliance with accessibility standards by maintaining a consistent vertical position despite changing loads.
Implementation Method 1
A piston is positioned within the chamber. The piston and the chamber are movable relatively to one another... A first and a second valve are mounted on either the piston or the chamber... The first valve has an inlet in fluid communication with the source of pressurized fluid, and an outlet in fluid communication with the secondary suspension and the chamber.
Implementation Method 2
A biasing element is positioned between the piston and the chamber, preferably within the chamber.
Implementation Method 3
An actuating mechanism extends between the first and second valves and the chassis. The actuating mechanism opens the first valve in response to motion of the body toward the chassis, and closes the first valve when the body is at a predetermined vertical position relative to the datum line.
Data Source
AI summary
A vertical position compensating device for a vehicle, a vehicle using the device, and a method for controlling the vertical position of a vehicle. The vehicle has a wheel set mounted on a chassis by a primary suspension system and a body mounted on the chassis through a secondary suspension system. The device is mounted on the body. As the vehicle is loaded or unloaded the device moves vertically with the body and also moves relative to the body in proportion to the deflection of the primary suspension system. The total motion of the device is used to adjust the vertical position of the body through the secondary suspension in a direction opposite to the deflection of the body to maintain the position of the body constant relative to a datum line.