Hydraulic Pump Monitoring for Force Conversion Efficiency Diagnosis

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Solution Overview

Problem

Existing hydraulic pump monitoring systems cannot effectively diagnose the force conversion efficiency, which is crucial for assessing the operational state and efficiency of hydraulic pumps, despite being able to diagnose speed conversion efficiency.

Innovation Solution

A hydraulic pump state monitoring device that measures feature amounts related to force conversion efficiency by monitoring the rotational force, tilting amount, and delivery pressure of a variable displacement hydraulic pump, using a controller to compute these parameters and determine the force conversion efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the leakage flow rate measurement method is used to diagnose speed conversion efficiency, then the diagnosis based on speed conversion efficiency is enabled, but the diagnosis based on force conversion efficiency cannot be executed

Engineering Contradiction:
Improvediagnosis capabilityVSAvoiddiagnosis scope
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The monitoring device is designed to perform multiple diagnosis functions by integrating both speed conversion efficiency monitoring (through delivery flow rate measurement) and force conversion efficiency monitoring (through delivery pressure and rotational force measurement). The controller computes both types of efficiency using a unified measurement system, making the device versatile for comprehensive pump health assessment.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines previously separate measurement approaches into a single integrated system. By merging the measurement of delivery flow rate, delivery pressure, and rotational force into one monitoring device, it enables simultaneous computation of both speed conversion efficiency and force conversion efficiency, resolving the limitation of only being able to diagnose one type of efficiency.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If comprehensive pump monitoring is implemented, then accurate diagnosis based on force conversion efficiency is achieved, but measurement and computation complexity increases

Engineering Contradiction:
Improvediagnosis accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The controller is designed as a multi-functional computing unit that can process multiple types of efficiency calculations using the same input data (delivery flow rate, delivery pressure, rotational force). This universal computation capability achieves accurate comprehensive diagnosis without requiring separate complex measurement systems for each efficiency type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4692545A1Hydraulic pump state monitoring device and hydraulic drive device
Publication Date: 2026.02.11 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP4692545A1 patent drawingFigure 1
  • EP4692545A1 patent drawingFigure 2
  • EP4692545A1 patent drawingFigure 3

AI summary

An object of the present invention is to provide a hydraulic pump state monitoring device that enables diagnosis of a hydraulic pump based on force conversion efficiency from input of the hydraulic pump to output thereof by measuring a feature amount relating to the force conversion efficiency. Accordingly, a controller computes, in a case in which the tilting amount of the hydraulic pump has become a predetermined tilting amount and the delivery pressure has become a predetermined pressure, a feature amount relating to the force conversion efficiency that is the efficiency of conversion from a rotational force of a prime mover to the delivery pressure of a hydraulic operating fluid concerning the hydraulic pump at a time when the delivery pressure of the hydraulic pump has become the predetermined pressure.