Hydraulic Pump Wear Detection Using Pressure and Command Current
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Solution Overview
Problem
Existing methods for detecting performance deterioration in hydraulic pumps, such as measuring drain flow rates, are prone to measurement inaccuracies due to the slight flow rates involved, making it difficult to detect minor decreases in delivery flow rates caused by wear in sliding components.
Innovation Solution
A hydraulic pump performance deterioration detection system that uses a variable displacement hydraulic pump, a switching valve, a regulator, control circuitry, and a pressure sensor to determine performance deterioration without relying on flowmeters. The system adjusts the pump's displacement based on a command current and measures delivery pressure to assess pump performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drain flow rate is measured by a flowmeter to detect hydraulic pump performance deterioration, then detection capability is provided, but measurement precision deteriorates due to the slight flow rate being readily affected by measurement precision limitations
Solution Approach 1:
The patent introduces an intermediary measurement approach by measuring delivery pressure instead of drain flow rate directly. The pressure sensor acts as an intermediary indicator that reflects pump performance deterioration through pressure changes caused by internal leakage variations, avoiding the direct measurement problem of slight flow rates
Solution Approach 2:
The patent changes the measurement parameter from flow rate to pressure. By monitoring delivery pressure variations under different displacement conditions, the system detects pump deterioration without encountering the precision limitations of flowmeter measurements on slight flow rates
2Reliability
If a flowmeter is used to measure drain flow rate, then performance deterioration detection is enabled, but device complexity increases due to additional measurement equipment
Solution Approach 1:
The pressure sensor serves multiple functions: it monitors delivery pressure for performance detection, controls regulator operation, and provides data for determining pump displacement characteristics. This multi-functionality eliminates the need for separate flowmeter equipment
Solution Approach 2:
The system uses existing pressure measurement capabilities within the hydraulic control system to detect pump deterioration, rather than adding external measurement equipment. The pressure data already collected for control purposes is repurposed for diagnostic functions
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
Enables accurate detection of hydraulic pump performance deterioration without using flowmeters, providing higher precision than traditional methods and allowing for real-time monitoring and maintenance, thus preventing downtime and ensuring continuous operation.
Implementation Method 1
a pressure sensor that measures the delivery pressure of the hydraulic pump
Data Source
AI summary
A hydraulic pump performance deterioration detection system according to one embodiment includes: a variable displacement hydraulic pump; a switching valve that is connected to the hydraulic pump by a pump line and to a hydraulic actuator by a supply/discharge line; and a regulator that changes a displacement of the hydraulic pump in accordance with a command current and that limits the displacement of the hydraulic pump to a limiting value when a delivery pressure of the hydraulic pump has become higher than a setting value. The performance deterioration detection system further includes: control circuitry that feeds the command current to the regulator; and a pressure sensor that measures the delivery pressure of the hydraulic pump. When the hydraulic actuator is not moving, the control circuitry determines whether or not performance of the hydraulic pump has deteriorated based on a current value of the command current and the delivery pressure of the hydraulic pump measured by the pressure sensor.