Hydraulic system and abnormality diagnosis method

The hydraulic system uses a variable displacement motor and sensors to calculate output torque and tilt angle, addressing the challenge of detecting and identifying abnormalities in hydraulic systems, enhancing maintenance efficiency in machinery like excavators and hydraulic shovels.

WO2026110490A1PCT designated stage Publication Date: 2026-05-28KAWASAKI JUKOGYO KK
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Patent Information

Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
KAWASAKI JUKOGYO KK
Filing Date
2025-09-29
Publication Date
2026-05-28

AI Technical Summary

Technical Problem

Existing hydraulic systems struggle to easily determine the presence of abnormalities and identify their causes, particularly in construction and industrial machinery, where a failure diagnosis device based on engine and hydraulic motor efficiency gradients is insufficient.

Method used

A hydraulic system incorporating a variable displacement hydraulic motor with a changeable tilt angle, pressure sensors, a tilt angle sensor, and a processing circuit to calculate output torque and tilt angle, allowing for the detection of abnormalities and identification of their causes based on pressure differences and tilt angle deviations.

Benefits of technology

Enables easy detection of abnormalities and precise identification of their causes in hydraulic systems, ensuring accurate diagnosis and maintenance of machinery like excavators and hydraulic shovels.

✦ Generated by Eureka AI based on patent content.

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    Figure JP2025034358_28052026_PF_FP_ABST
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Abstract

A hydraulic system (1) according to one embodiment includes a variable-displacement hydraulic motor (41), hydraulic pumps (21, 22), a plurality of pressure sensors (9), a tilt angle sensor (82), and a processing circuit (71). The pressure sensors (9) include a pair of motor pressure sensors (92, 93). The processing circuit (71) calculates an output torque of the hydraulic motor (41) on the basis of a pressure difference between an inlet pressure and an outlet pressure of the hydraulic motor (41) detected by the pair of motor pressure sensors (92, 93) and a tilt angle of the hydraulic motor (41) detected by the tilt angle sensor (82), determines the presence or absence of an abnormality in the hydraulic system (1) on the basis of the calculated output torque and the tilt angle of the hydraulic motor (41), and if there is an abnormality in the hydraulic system (1), identifies the cause of the abnormality in the hydraulic system (1) on the basis of the plurality of pressures detected by the pressure sensors (9) and the tilt angle detected by the tilt angle sensor (82).
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Citation Information

Patent Citations

  • Oil pressure closing circuit for construction machine

    JP1991219167A

  • Hydraulic work machine

    JP2019049102A

  • Abnormality diagnosis system and abnormality diagnosis method

    JP2024142668A