Rail Vehicle Secondary Suspension Traction Cylinder Decoupling
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Solution Overview
Problem
The existing secondary suspension systems in rail vehicles experience wear and reaction time issues due to the partial vacuum created in the traction cylinder during vehicle dynamics, leading to damage to seals and cavitation effects.
Innovation Solution
Mechanical decoupling of the downward movement of the car body from pressure reduction in the traction cylinder, preventing the generation of a partial vacuum and reducing wear on hydraulic system seals by ensuring the piston remains stationary during downward movements, while allowing upward movement to occur without significant pressure issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the traction cylinder allows free piston movement during car body dynamics, then the system responds quickly to movement forces, but partial vacuums are generated in the pressure chamber causing seal damage and cavitation
Solution Approach 1:
A mechanical decoupling device is introduced as an intermediary between the piston rod and the piston. This decoupling device allows the piston rod to move freely during downward car body movements while preventing the piston from moving, thus avoiding partial vacuum generation. The decoupling device acts as a mediator that selectively transmits or blocks movement based on the direction of force.
Solution Approach 2:
The connection between the piston rod and piston is segmented into two independent movement paths: one for the piston rod that allows free movement, and another for the piston that remains constrained. This segmentation is achieved through the mechanical decoupling device that separates the kinematic chains, allowing differential movement behavior between the rod and piston components.
2Duration of action of stationary object
If the piston is mechanically decoupled from the piston rod during downward movement, then partial vacuums are avoided and seal wear is reduced, but the device structure becomes more complex
Solution Approach 1:
The mechanical decoupling device serves as an intermediary component that extends the service life of the traction cylinder by preventing vacuum-related damage to seals and hydraulic components. Although it adds structural elements, it eliminates the need for frequent seal replacements and hydraulic system overhauls, thereby increasing overall system durability.
Solution Approach 2:
The decoupling mechanism provides beforehand protection against vacuum formation by mechanically preventing piston movement that would create partial vacuums. This proactive measure cushiones the hydraulic system against cavitation and seal damage before these issues can occur, extending component service life.
3Object-affected harmful factors
If the piston rod moves freely during downward car body movement, then the mechanical decoupling prevents vacuum formation, but the piston may not respond to upward movement forces efficiently
Solution Approach 1:
The mechanical decoupling device is designed with dynamic characteristics that allow it to adapt to different movement directions. During downward movement, it decouples the piston from the rod to prevent vacuum formation. During upward movement, the device can re-engage or allow piston movement through hydraulic pressure, maintaining system responsiveness while avoiding harmful vacuum effects.
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 significantly extends the service life of the traction cylinder and its seals, reducing the need for frequent overhauls and maintaining quick reaction times by preventing seal damage and cavitation.
Implementation Method 1
a steel spring as a passive spring element which is arranged between the car body and a bogie and which ensures at least a raised travel level for the car body
Implementation Method 2
the traction cylinder is a hydraulic cylinder which can be acted on at one end
Data Source
AI summary
A device for the secondary suspension of a body of a rail vehicle, the device comprising a spring element which is between the body and a bogie and to ensure at least one raised transport level for the body during the journey of the rail vehicle. The spring element can be compressed by a traction cylinder when the rail vehicle is stationary, in order to adjust a sunken platform level for the body, which is arranged below the raised driving level. The traction cylinder is provided with means for mechanically decoupling the advancing movement of the body from a pressure reduction in the pressure chamber of the traction cylinder.