Piston Accumulator Guide Rod for Accurate Internal Position Sensing
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Solution Overview
Problem
Existing hydropneumatic piston accumulators face challenges in accurately determining the position of the piston, with existing solutions being complex or requiring external components, such as ultrasonic or magnetic field sensors, which are not reliable or efficient.
Innovation Solution
A hydropneumatic piston accumulator design featuring a rod-like guide that extends through the piston, sealed by a sealing device, and utilizing a magnetostrictive measuring system with a pressure-resistant, non-magnetic cladding tube, allowing for accurate and reliable position determination without complex seals or external components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic sensors are used to determine piston position, then position measurement is achieved, but the system becomes complex and requires continuous error correction due to changing sound propagation speed
Solution Approach 1:
The patent replaces complex ultrasonic measurement systems with a simple magnetic field-based measurement approach. A magnet is mounted on the piston, and magnetic field sensors detect its position directly, eliminating the need for ultrasonic transducers and complex error correction algorithms while achieving accurate position measurement.
Solution Approach 2:
The patent extracts the measurement function from complex external sensor systems and integrates it directly into the accumulator structure by mounting magnets on the piston and placing magnetic field sensors on the housing, creating a simplified self-contained measurement system.
2Measurement precision
If magnetic field sensors are arranged on the outside of the accumulator housing, then piston position can be determined, but an external magnetic strip must be attached to the housing
Solution Approach 1:
The patent merges the measurement system with the accumulator structure by integrating magnetic field sensors directly into the housing and mounting the magnet on the piston. This eliminates the need for separate external magnetic strips and simplifies assembly while maintaining measurement accuracy.
3Reliability
If a rod-like guide extends through the piston for structural support, then guidance and sealing are improved, but the seal between piston and guide becomes complex under pressure
Solution Approach 1:
The patent uses the hydraulic pressure itself to simplify the sealing problem. The rod-like guide is designed to work with the pressure differential, where the sealing device leverages the existing pressure environment to maintain reliable sealing without requiring complex multi-component sealing arrangements.
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 design ensures more accurate and reliable position measurement and secure media separation, enhancing the functionality and operational efficiency of the piston accumulator.
Implementation Method 1
utilizing a magnetostrictive measuring system with a pressure-resistant, non-magnetic cladding tube
Data Source
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AI summary
A hydropneumatic piston accumulator, with an accumulator housing (1) defining a housing longitudinal axis (11), in which a piston (9) is longitudinally movable between two housing covers (5, 7) positioned opposite each other. In the housing (1), the piston (9) separates a working chamber (13) for a compressible medium, such as a working gas, from a working chamber (15) for an incompressible medium, such as hydraulic fluid, and comprises at least a part (55) of a displacement measurement device continuously determining each position of the piston (9) in the housing (1). The invention is characterised in that a rod-like guide (29, 57) is stationarily positioned in the accumulator housing (1) and passes all the way through the piston (9) in each of its displacement positions in the accumulator housing (1), the piston (9) being movably guided therealong until it reaches the stop on one of the two housing covers (5, 7), and in that the piston (9) is sealed against this guide (29, 57) using a sealing device (49, 50).