Hydraulic Pump Dry Operation Detection via Dynamic Pressure Threshold

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing fluid pressure units, such as hydraulic power units, face challenges in detecting dry operation states of hydraulic pumps, leading to potential seizing due to insufficient fluid suction, which conventional detection methods fail to address effectively across all rotation speed ranges.

Innovation Solution

A fluid pressure unit with a pressure detection system that sets a preset pressure based on the driving rotation speed of the pump, allowing for the detection of dry operation by monitoring the discharge pressure, which becomes the judgment reference pressure for abnormal operation, enabling timely intervention to prevent pump seizing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional dry operation detection means is applied to the hydraulic power unit, then detection can be achieved in high rotation speed states, but detection fails in low rotation speed states where air mixing occurs

Engineering Contradiction:
Improvedetection reliabilityVSAvoiddetection coverage across rotation speeds
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention applies dynamics by making the detection threshold dynamic rather than fixed. The judgment reference pressure is adjusted based on the rotation speed of the hydraulic pump, allowing the detection system to adapt to different operating conditions. This resolves the contradiction by enabling reliable detection across both high and low rotation speed states through dynamic threshold adjustment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter used for detection from a fixed pressure threshold to a variable threshold that depends on rotation speed. By establishing a relationship between rotation speed and judgment reference pressure, the system can accurately detect dry operation conditions across the entire rotation speed range, not just at high speeds.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a fixed pressure threshold is used for dry operation detection, then the detection system is simple, but it cannot accurately detect dry operation across all rotation speeds

Engineering Contradiction:
Improvedetection system complexityVSAvoiddry operation detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The detection system uses dynamic threshold adjustment based on rotation speed rather than a fixed threshold. This maintains relative simplicity while significantly improving detection accuracy across different operating conditions, resolving the contradiction between system complexity and measurement precision.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the hydraulic pump continues operation in dry operation state, then productivity is maintained, but the pump may seize due to lubrication insufficiency

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidpump seizure prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention implements feedback control by continuously monitoring the relationship between rotation speed and discharge pressure. When the discharge pressure falls below the rotation speed-dependent judgment reference pressure, the system detects dry operation and can trigger protective actions, providing feedback that prevents pump seizure while minimizing impact on productivity.

Inventive Principle:
Principle #23Feedback

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 solution ensures definite detection of dry operation across various rotation speeds, preventing hydraulic pump seizing and enhancing the reliability of fluid pressure units by stabilizing the detection of discharge pressure abnormalities.

Implementation Method 1

a pressure detection means for detecting a discharge pressure of the fluid pressure pump

Methodology Applied
Scientific EffectPressure detection:

Data Source

PatentEP2055965B1Fluid pressure unit
Publication Date: 2013.02.27 DAIKIN INDUSTRIES LTD
  • EP2055965B1 patent drawingFigure 1~2
  • EP2055965B1 patent drawingFigure 3~4

AI summary

A pressure sensor (17) is provided for detecting the discharge pressure of a hydraulic pump (11). An abnormality detection section (23) of a controller (21) detects a dry operation of the hydraulic pump (11) when the discharge pressure detected by the pressure sensor (17) becomes equal to or lower than a judgment reference pressure determined in advance according to the driving rotation speed of the hydraulic pump (11).