Axial Piston Pump Cylinder Block Motion Sensing Without Intrusion
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Solution Overview
Problem
Existing methods for condition monitoring and fault diagnosis of axial piston pumps are hindered by the submersion of fault signals in background noise due to indirect measurement through shell vibrations, and modifications to the rotating components affect dynamic characteristics, with insufficient attention to transient characteristics of the cylinder block's tilting behavior.
Innovation Solution
A non-intrusive method using eddy current sensors to measure radial displacement and contour signals of the cylinder block, aligning these signals through cross-correlation, and calculating radial vibration and tilt characteristics with minimal modification to the pump, enabling accurate transient analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vibration signal of the shell is used for condition monitoring, then fault signal can be detected, but the fault signal is submerged in background noise due to indirect transmission through the shell
Solution Approach 1:
The patent extracts the fault signal directly from the rotating component (cylinder block) rather than relying on indirect transmission through the shell. By installing sensors directly on the rotating component, the method separates the fault signal from the background noise that contaminates shell vibration signals, thereby improving detection accuracy.
Solution Approach 2:
The patent introduces a non-contact measurement system with sensors that act as intermediaries between the rotating component and the measurement system. This intermediary approach allows direct capture of the cylinder block's vibration and tilt signals without requiring modification of the component itself, while avoiding the noise interference that occurs with shell-based measurement.
2Measurement precision
If the rotating component is modified to measure dynamic characteristics, then measurement information can be obtained, but the dynamic characteristics of the cylinder block are affected
Solution Approach 1:
The patent replaces contact-based mechanical measurement methods with non-contact optical measurement systems. By using optical sensors to measure the cylinder block's displacement and tilt without physical contact, the method eliminates the need to modify the rotating component, thereby preserving its original dynamic characteristics while still obtaining accurate measurement data.
3Ease of manufacture
If non-contact measurement method is used, then the pump requires less modification, but accurate measurement of transient characteristics and tilt motion becomes more difficult
Solution Approach 1:
The patent segments the measurement into multiple independent components: radial displacement measurement and tilt angle measurement. By measuring these separate parameters simultaneously and processing them independently, the method achieves accurate transient characteristic analysis without requiring complex modifications to the pump structure.
Solution Approach 2:
The patent adds the dimension of tilt angle measurement to the traditional radial displacement measurement. By combining radial displacement data with tilt angle data from optical sensors, the method comprehensively captures the transient characteristics of the cylinder block without requiring physical contact or modification of the component.
4Measurement precision
If fault signal transmission path is made shorter by measuring rotating component directly, then fault signal strength improves, but measurement system complexity increases
Solution Approach 1:
The patent employs optical sensors that serve multiple functions: measuring radial displacement, detecting tilt angle, and capturing transient characteristics. By using a multi-functional measurement system, the method strengthens the fault signal transmission path while avoiding the need for multiple separate measurement devices, thereby managing system complexity.
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 method ensures accurate measurement of the cylinder block's real displacement and motion, allowing for online fault detection and reduced interference from test equipment, suitable for commercial pumps.
Implementation Method 1
acquiring radial displacement signals along X axis and Y axis on two cross sections of the cylinder block surface of the test pump by using two groups of eddy current sensors
Data Source
AI summary
Provided is a dynamic characteristic measurement method for a cylinder block of a non-intrusive axial piston pump. The cylinder block is the main rotating component of the axial piston pump, and the dynamic characteristic of the cylinder block is more capable of reflecting the health condition of the pump than an external characteristic. A non-contact type measurement scheme is provided so as to reduce the influence of a measurement device on the motion of the cylinder block. Cylinder block contour signals and radial displacement signals are obtained by measuring the radial displacement of two sections of the surface of the cylinder block under different working conditions in the perpendicular directions, and then the cylinder block contour signals are accurately removed from the radial displacement signals to obtain the translational and tilting motion characteristics of the cylinder block.