Railcar Wheel Load Adjusting Apparatus Curve Pressure Control
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Solution Overview
Problem
Existing wheel load adjusting apparatuses for railcars fail to maintain pressure balance among air springs during curve traversal, leading to wheel load variation.
Innovation Solution
The apparatus includes first and second air springs between the carbody and a first bogie, and third and fourth air springs between the carbody and a second bogie, with automatic level controlling valves that adjust their heights to maintain constant heights and limit air supply/discharge operations to prevent pressure differences between air springs, thereby suppressing wheel load variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the automatic level controlling valve adjusts air supply and discharge to maintain constant air spring height, then the height stability is improved, but the pressure difference between air springs increases during curve traversal
Solution Approach 1:
A new type of level controlling valve is introduced as an intermediary device that mediates between the air supply system and the air spring. This valve incorporates both a height adjustment function and a pressure difference suppression function, allowing it to balance the conflicting requirements of maintaining constant height while preventing excessive pressure differences during curve traversal.
Solution Approach 2:
The level controlling valve is designed with multi-functionality, simultaneously performing height maintenance and pressure difference suppression. By integrating both functions into a single valve, the system can address both the height stability requirement and the pressure balance requirement without needing separate control mechanisms.
2Stress or pressure
If the air spring pressure is adjusted to compensate for torsional force during curve traversal, then the wheel load balance is improved, but the height control precision deteriorates
Solution Approach 1:
The control function is segmented into two independent aspects: height control and pressure difference suppression. The level controlling valve handles height control by adjusting air supply and discharge, while the new valve mechanism separately handles pressure difference suppression. This segmentation allows each function to operate independently without interfering with the other, maintaining both height precision and wheel load balance.
Solution Approach 2:
The level controlling valve acts as an intermediary that coordinates between height control and pressure balance requirements. It receives input about both height deviations and pressure differences, then selectively adjusts air flow to satisfy both conditions, preventing the trade-off between height precision and wheel load balance.
3Speed
If the existing level controlling valve operates freely to maintain air spring height, then the height adjustment response is improved, but the wheel load variation increases during curve traversal
Solution Approach 1:
The system incorporates feedback mechanisms that monitor both air spring height and pressure differences. The level controlling valve receives feedback about the current state and adjusts its operation accordingly, slowing down air discharge when pressure differences become excessive during curve traversal. This feedback control allows the system to maintain rapid height adjustment response while preventing wheel load variation caused by excessive pressure differences.
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 configuration effectively reduces wheel load variation by maintaining load balance among air springs during curve traversal, preventing pressure differences and subsequent wheel load changes.
Implementation Method 1
an automatic level controlling valve configured to supply and discharge air to and from an air spring interposed between a carbody and a bogie. When the air spring expands in a vertical direction, the automatic level controlling valve discharges air from the air spring. When the air spring contracts in the vertical direction, the automatic level controlling valve supplies compressed air to the air spring.
Implementation Method 2
when the railcar passes through a curve, the wheel load adjusting apparatus limits an air supply/air discharge operation of at least one of the first to fourth automatic level controlling valves so as to suppress an increase in a pressure difference between at least two of the first to fourth air springs.
Data Source
AI summary
A wheel load adjusting apparatus used in a railcar, and the railcar includes: first and second air springs arranged between a carbody and a first bogie so as to be spaced apart from each other in a car width direction; third and fourth air springs arranged between the carbody and a second bogie so as to be spaced apart from each other in the car width direction; and first to fourth automatic level controlling valves provided upstream of the first four air springs and configured to adjust heights of the four air springs to maintain constant height of the air springs, wherein when the railcar passes through a curve, the wheel load adjusting apparatus limits an air supply/air discharge operation of at least one of the four automatic level controlling valves to suppress an increase in a pressure difference between at least two of the four air springs.