Piston-Cylinder Position Detection Using Resonant Circuit
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Solution Overview
Problem
Existing piston-cylinder units face challenges in precise position determination due to the need for elaborate and cost-intensive modifications, requiring external sensors and transducers, which complicates the integration of position measurement systems, especially in high-control-pressure applications like construction machines and hoisting equipment.
Innovation Solution
A piston-cylinder unit is configured as an electrical series-resonant circuit using the cylinder jacket and piston as electrodes, with an exciter generating a resonant frequency that allows for position determination without additional sensors or transducers, utilizing the cylinder and piston components to form an oscillating circuit, and employing a sliding contact or capacitive ring for signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external sensors or transducers are integrated into the piston-cylinder unit for position detection, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the position detection function with the existing piston-cylinder structure by forming an oscillating circuit using the piston, cylinder jacket, and hydraulic medium as integral components. This eliminates the need for separate external sensors or transducers, thereby maintaining measurement precision while reducing device complexity and manufacturing cost.
Solution Approach 2:
The piston and cylinder jacket serve dual functions: their primary mechanical function and their role as electrodes forming an oscillating circuit for position detection. This multi-functionality eliminates the need for dedicated position sensing components, resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If additional sensors and transducers are integrated into the piston-cylinder unit, then position determination accuracy is improved, but ease of manufacture deteriorates
Solution Approach 1:
The position determination system is merged with the existing piston-cylinder components. The piston, cylinder jacket, and hydraulic medium collectively form the oscillating circuit, eliminating the need for additional manufactured parts and simplifying the manufacturing process while maintaining position determination accuracy.
Solution Approach 2:
The piston-cylinder unit uses its own existing components (piston, cylinder jacket, hydraulic medium) to perform the position detection function. This self-service approach eliminates the need for externally supplied sensors and transducers, thereby improving ease of manufacture while maintaining measurement accuracy.
3Measurement precision
If the piston-cylinder unit is modified with position measuring devices, then position detection capability is improved, but reliability deteriorates due to interference with high control pressures
Solution Approach 1:
The position detection system is merged with the existing piston-cylinder structure, using the piston and cylinder jacket as integral parts of the oscillating circuit. This eliminates the need for separate position measuring devices that could be interfered with by high control pressures, thereby maintaining both position detection capability and system reliability.
4Measurement precision
If external position sensing components are added to the piston-cylinder unit, then position measurement precision is improved, but production cost increases
Solution Approach 1:
The position measurement system is merged with the existing piston-cylinder components, eliminating the need for expensive external sensors and transducers. The oscillating circuit is formed using readily available components (piston, cylinder jacket, hydraulic medium), thereby maintaining position measurement precision while significantly reducing production cost.
Solution Approach 2:
The piston-cylinder unit uses its own existing components to perform position measurement, eliminating the need to purchase and install external sensing equipment. This self-service approach maintains measurement precision while reducing production cost.
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 approach enables precise position determination with stability and robustness, reducing production and installation costs by leveraging existing components and eliminating the need for external sensors, while maintaining electromagnetic compatibility through shielding and frequency stabilization.
Implementation Method 1
the cylinder jacket and cylinder piston function as the electrodes of a series-resonant circuit
Implementation Method 2
Opposite surfaces of the piston and cylinder jacket form a capacitance with hydraulic media
Implementation Method 3
the resonant frequency that is set up in an oscillating circuit is a function of the capacitance and inductance
Implementation Method 4
the exciter according to the present disclosure serves to excite the electrical series-resonant circuit to oscillate at its resonant frequency
Data Source
AI summary
The present disclosure relates to a piston-cylinder unit with a device for determining position, the device comprising at least one exciter that is indirectly or directly electrically connected with the cylinder jacket and the cylinder piston of the piston-cylinder unit, and that excites the electrical oscillating circuit formed by the piston-cylinder unit and the contact lines to oscillate at its resonant frequency, it being possible to measure an electrical signal characterizing the resonant frequency on the piston-cylinder unit. The invention also relates to a construction machine or piece of hoisting equipment with such a piston-cylinder unit.