Hydraulic Cylinder Piston Position Sensing With RF Collimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hydraulic piston and cylinder units in working machines face challenges in accurately determining the axial position of the piston using complex and expensive magnetostrictive sensors.
Innovation Solution
A piston and cylinder unit equipped with a piston position detection unit that utilizes high-frequency technology, including an antenna for sending and receiving high-frequency signals, and a collimator to improve signal quality and precision by filtering out undesired radiation and amplifying parallel beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetostrictive sensors are used to determine the axial position of the piston, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical magnetostrictive sensor system with a high-frequency electromagnetic wave-based detection system. An antenna emits high-frequency signals that travel through the hydraulic fluid to the piston, where reflections occur. The reflected signals are received and processed to determine piston position, eliminating the need for complex mechanical sensors while maintaining measurement precision.
Solution Approach 2:
The patent introduces hydraulic fluid as an intermediary medium for signal transmission. The high-frequency signals propagate through the hydraulic fluid to reach the piston and return reflections, allowing position detection without direct mechanical contact or complex sensor structures. The fluid serves as the transmission medium that simplifies the overall system architecture.
2Length of stationary object
If high-frequency signals are transmitted over greater distances through hydraulic fluid, then measurement range is improved, but signal quality deteriorates due to damping
Solution Approach 1:
The patent optimizes the frequency parameter of the transmitted signals to balance penetration depth and signal quality. By carefully selecting the high-frequency range, the system achieves sufficient signal strength for long-distance transmission through hydraulic fluid while maintaining adequate signal quality for accurate position determination. The frequency is tuned to minimize damping effects over the required measurement range.
3Adaptability or versatility
If the antenna radiates high-frequency signals in all directions, then signal coverage is improved, but measurement precision deteriorates due to unwanted reflections
Solution Approach 1:
The patent implements directional radiation characteristics for the antenna, concentrating the high-frequency signal energy in the specific direction toward the piston rather than radiating uniformly in all directions. This localized signal focus improves measurement precision by reducing unwanted reflections from surrounding structures while maintaining adequate signal coverage for the measurement range. The antenna design or positioning creates a focused beam pattern aligned with the piston-cylinder axis.
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 enables precise determination of the axial position of the piston with minimal structural effort, improving signal quality and measurement accuracy, especially at greater distances between the piston and cylinder head.
Implementation Method 1
The piston position detection unit serves to determine the axial position of the piston in the cylinder by high frequency technology, and it includes an antenna for sending and receiving high frequency signals
Implementation Method 2
A collimator is arranged in the beam path of the antenna. The collimator improves precision of the piston position detection unit in a plurality of ways, and it leads to improved measuring results when determining the position of the piston
Data Source
AI summary
A piston and cylinder unit of a working machine, for example a wheel loader, excavator, tipper or crane serves to steer, pivot, lift or provide other movements of the working machine or of a tool. The piston and cylinder unit includes a cylinder, a piston being arranged in the cylinder to be axially movable along a longitudinal center axis and a piston position detection unit. The cylinder includes a mounting bore extending radially in the cylinder. The piston position detection unit is arranged in the mounting bore and detects the axial position of the piston in the cylinder by high frequency technology. The piston position detection unit includes an antenna for sending and receiving high frequency signals. A collimator is arranged in the beam path of the antenna. The antenna has a main sense of direction of radiation extending parallel to the longitudinal center axis.