Closed-Circuit Bogie Test Stand for Precise Low-Energy Loading
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Solution Overview
Problem
Existing bogie test stands using hydraulic or electric load cylinders are costly, energy-intensive, and require high maintenance, with hydraulic cylinders being sensitive to lateral forces and electric cylinders being expensive.
Innovation Solution
A bogie test stand utilizing a double-acting hydraulic cylinder with a bi-directional axial piston pump, a compensating reservoir, and a servomotor, forming a closed hydraulic system, which reduces energy consumption and maintenance costs while allowing precise control and high dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic load cylinders with auxiliary yoke are used, then lateral forces are absorbed, but manufacturing costs and maintenance costs increase
Solution Approach 1:
The patent removes the auxiliary yoke component from the hydraulic cylinder assembly. The hydraulic cylinder is designed to operate without this additional lateral force absorption component, simplifying the overall structure while maintaining functionality through the closed-circuit hydraulic system's inherent stability.
Solution Approach 2:
The closed-circuit hydraulic system with axial piston pump provides self-stabilizing characteristics that eliminate the need for external auxiliary structures. The system uses its own hydraulic fluid circulation and pressure regulation to maintain stability under lateral loads, rather than requiring separate mechanical support components.
2Ease of operation
If electric load cylinders with synchronous motor are used, then precise control is achieved, but manufacturing costs increase
Solution Approach 1:
The patent replaces electric motors and drive electronics with a hydraulically actuated system. The axial piston pump driven by a simple motor converts rotational motion to hydraulic pressure, which then actuates the cylinder. This mechanical-hydraulic substitution eliminates complex electrical control systems while maintaining precise control through hydraulic pressure regulation.
Solution Approach 2:
The invention uses a closed-circuit hydraulic system with an axial piston pump to provide force application. This hydraulic approach replaces electric cylinder mechanisms, leveraging fluid power transmission to achieve precise force control with simpler and more cost-effective components.
3Force
If hydraulic or electric load cylinders are used, then force application is achieved, but energy consumption increases
Solution Approach 1:
The closed-circuit hydraulic system maintains continuous hydraulic pressure and fluid circulation, allowing the system to hold position and apply force without continuous energy input. The hydraulic fluid acts as an energy storage medium, maintaining system pressure and readiness without active power consumption during idle periods.
Solution Approach 2:
The axial piston pump can vary its displacement and output pressure based on system demands, optimizing energy consumption. The pump adjusts hydraulic parameters (flow rate, pressure) to match actual test requirements, avoiding constant high-energy operation and reducing overall power consumption compared to fixed-displacement electric systems.
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 achieves low energy consumption, reduced maintenance, and lower manufacturing costs, enabling efficient and precise simulation of forces on bogies, particularly suitable for testing spring and damper elements made of elastomeric materials.
Implementation Method 1
a bi-directional axial piston pump for pressurizing the cylinder chambers of the hydraulic cylinder with hydraulic fluid
Data Source
AI summary
A test stand for testing bogies of rail vehicles is described herein. The test stand includes a load application unit for generating a linear application force for a bogie to be tested. The load application unit includes a hydraulic cylinder with a piston rod. The hydraulic cylinder is a double-acting cylinder, the cylinder chambers of which are pressurized with hydraulic fluid by a bi-directional axial piston pump. The test stand further includes a transmission unit for transmitting the application force to the bogie, the transmission unit being operatively connected to one end of the piston rod.