Hydraulic machine, system for monitoring health of hydraulic machine, and method thereof

• US 7,082,758 B2
• Filed: 05/17/2005
• Issued: 08/01/2006
• Est. Priority Date: 05/21/2004
• Status: Expired due to Fees

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Kageyama, Masato, Shoji, Yukio, Yoshida, Nobumi
• Primary Examiner(s): Lazo, Thomas E.
• Application Number:
  US11/130,408
• Publication Number:
  US 20050262838A1
• Time in Patent Office: 441 Days
• Field of Search: 603/28, 603/29, 604/53, 604/45
• US Class Current: 60/445
• CPC Class Codes: E02F 9/20 Drives; Control devices gearings in general F16H; controlling in general G05; electric multi-motor drives H02K, H02P
• CPC Class Codes: E02F 9/226 Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
• CPC Class Codes: E02F 9/2296 Systems with a variable displacement pump
• CPC Class Codes: F04B 51/00 Testing machines, pumps, or pumping installations
• CPC Class Codes: F15B 19/005 Fault detection or monitoring
• CPC Class Codes: F15B 21/041 Removal or measurement of solid or liquid contamination, e.g. filtering
• CPC Class Codes: F15B 21/085 using a data bus, e.g. "CANBUS"
• CPC Class Codes: F16D 31/02 using pumps with pistons or plungers working in cylinders

Abstract

In a hydraulic machine, hydraulic pump failure is detected and the pump lifespan is estimated before the pump failure occurs. The discharge pressure 122, oil temperature 126, and drain filter differential pressure 120 are measured, a correlative relationship 128 between the filter differential pressure and the discharge pressure is determined, and a representative filter differential pressure 130 is calculated from this correlative relationship. Using an oil temperature-differential pressure correlation function, the representative differential pressure value 130 is corrected so that the variable component 132 caused by the oil temperature 126 is eliminated therefrom. The long-term trend and the short-term trend of the increase over time of the corrected differential pressure is calculated. A pump failure is predicted or the pump lifespan is estimated based on the degree of deviation between the long-term trend and the short-term trend.

Claims

1. A hydraulic machine, comprising:

a hydraulic loading device;

a hydraulic pump which discharges pressurized operating oil and supplies the operating oil to said hydraulic loading device;

a drain filter which captures contaminants included in the operating oil which flows into the drain of said hydraulic pump;

a differential pressure sensor which measures a filter differential pressure across said drain filter;

an operating status sensor which measures a specified operating status of said hydraulic pump;

a data collector which collects time series data of said filter differential pressure and time series data of said operating status from said differential pressure sensor and said operating status sensor; and

a representative differential pressure determining unit which determines a representative differential pressure value which is the representative value of said filter differential pressure under said operating status which meets specified fixed conditions based on said time series data of said operating status and said time series data of said filter differential pressure collected by said data collector, and which output said determined representative differential pressure value.

2. The hydraulic machine according to claim 1, further comprising a diagnostic unit which diagnoses the health of said hydraulic pump based on said representative differential pressure value output from said representative differential pressure determining unit.

3. The hydraulic machine according to claim 1 or claim 2, wherein said operating status sensor measures as said operating status the pressure or flow of said pressurized operating oil which is supplied to said hydraulic loading device from said hydraulic pump.

4. The hydraulic machine according to claim 1 or claim 2, wherein said representative differential pressure determining unit determines the correlative relationship between said operating status and said filter differential pressure based on said time series data of said operating status and said time series data of said filter differential pressure, determine a correlation value of said filter differential pressure corresponding to a single specified representative of said operating status value which meets said fixed conditions based on said determined correlative relationship, and utilizes said determined correlation value as said representative differential pressure value.

5. The hydraulic machine according to claim 1 or claim 2, wherein said representative differential pressure determining unit extracts data under said operating status which meets said fixed conditions from said time series data of said filter differential pressure, determines the mean or median value of said extracted filter differential pressure data, and utilizes said determined mean or median value as said representative differential pressure value.

6. The hydraulic machine according to claim 1 or claim 2, wherein said hydraulic pump is a variable capacity pump, a capacity information outputting unit which outputs capacity information which correlates to said hydraulic pump capacity is further provided, and said representative differential pressure determining unit acquires said time series data of said operating status and said time series data of said filter differential pressure measured when said hydraulic pump capacity meets specified fixed conditions based on said capacity information and determine said representative differential pressure value based on said acquired time series data of said operating status and said acquired time series data of filter differential pressure.

7. The hydraulic machine according to claim 1 or claim 2, further comprising a temperature sensor for measuring the temperature of said operating oil, said data collector also collects time series data of said oil temperature from said temperature sensor, and said representative differential pressure determining unit uses said time series data of said oil temperature to correct said representative differential pressure value by reducing the oil temperature induced variable component included therein, and outputs said corrected representative differential pressure value.

8. A hydraulic pump health monitoring system for a hydraulic machine, comprising a hydraulic pump, a drain filter which captures contaminants included in operating oil which flows to a drain of said hydraulic pump, a differential pressure sensor which measures a filter differential pressure across said drain filter, and an operating status sensor which detects a specified operating status of said hydraulic pump, comprising:

a data collector which collects time series data of said filter differential pressure and time series data of said operating status from said differential pressure sensor and said operating status sensor; and

a representative differential pressure determining unit which determinea a representative differential pressure value which is a representative value of said filter differential pressure under said operating status which meets specified fixed conditions based on said time series data of said operating condition and said time series data of said filter differential pressure collected from said data collector.

9. The hydraulic pump health monitoring system according to claim 8, further comprising a diagnostic unit which diagnoses the health of said hydraulic pump based on said representative differential pressure value determined by said representative differential pressure determining unit.

10. The hydraulic pump health monitoring system according to claim 9 wherein said diagnostic unit collects time series data of said representative differential pressure value from said representative differential pressure determining unit, determines a correlative relationship between time lapse and an increase of said representative differential pressure based on said collected time series data of said representative differential pressure value, and has a lifespan estimator which estimates a life span of said hydraulic pump based on said determined correlative relationship.

11. The hydraulic pump health monitoring system according to claim 9 wherein said diagnostic unit collects time series data of said representative differential pressure value from said representative differential pressure determining unit, determines a correlative relationship over a specified long time period between time lapse and said representative differential pressure based on said collected time series data of said representative differential pressure value, determines a degree of deviation between said determined correlative relationship over said long time period and said representative differential pressure data over a specified recent short time period, and has an abnormality judging unit which judges abnormalities with said hydraulic pump based on said determined degree of deviation.

12. A hydraulic pump health monitoring method for a hydraulic pump which discharges pressurized operating oil and supplies the operating oil to a hydraulic loading device, comprising the steps of:

collecting time series data of a filter differential pressure across a drain filter of said hydraulic pump;

collecting time series data of a specified operating status for said hydraulic pump;

determining a representative differential pressure value which is a representative value of said filter differential pressure under said operating status which meets specified fixed conditions based on said time series data of said collected operating status and said time series data of said filter differential pressure; and

diagnosing said hydraulic pump health based on said determined representative differential pressure value.

13. A hydraulic pump health monitoring system for a hydraulic machine, comprising a hydraulic pump, a drain filter for capturing contaminants included in operating oil which flows to a drain of said hydraulic pump, a differential pressure sensor which measures a filter differential pressure across said drain filter, and an operating status sensor which detects a specified operating status of said hydraulic pump, comprising:

a local controller connected to said hydraulic machine; and

a central server which is placed in a location separated from said hydraulic machine and which can communicate with said local controller;

said local controller of said hydraulic machine comprising;

a data collector which collects time series data of said filter differential pressure and time series data of said operation status from said differential pressure sensor and said operating status sensor of said hydraulic machine;

a representative differential pressure determining unit which determines a representative differential pressure value which is said representative filter differential pressure value under said operating status which meets specified fixed conditions based on said time series data of said operating status and said time series data of said filter differential pressure collected by said data collector; and

a transmission unit which transmits to said server said representative differential pressure value determined by said representative differential pressure determining unit;

said central server comprising;

a receiving unit which receives said representative differential pressure value from said local controller; and

a diagnostic unit which diagnoses the health of said hydraulic machine based on said received representative differential pressure value.

14. A hydraulic pump health monitoring system for a hydraulic machine, comprising a hydraulic pump, a drain filter which captures contaminants included in operating oil which flows to a drain of said hydraulic pump, a differential pressure sensor which measures a filter differential pressure across said drain filter, and a temperature sensor which measures the temperature of said operating oil, comprising:

a data collector which collects time series data of said filter differential pressure and time series data of said oil temperature from said differential pressure sensor and said temperature sensor;

a correcting unit which uses said time series data of said oil temperature collected by said data collector and corrects said time series data of said filter differential pressure to reduce the temperature induced variable component therein; and

a diagnostic unit which diagnoses the health of said hydraulic pump based on said time series data of said filter differential pressure corrected by said correcting unit.

15. A hydraulic pump health monitoring system for a hydraulic machine, comprising a hydraulic pump, a drain filter which captures contaminants included in operating oil which flows to a drain of said hydraulic pump, and a differential pressure sensor which measures a filter differential pressure across said drain filter, comprising:

a data collector which collects time series data of said filter differential pressure from said differential pressure sensor;

a correlative relationship determining unit which determines a correlative relationship between time lapse and an increase of said filter differential pressure based on said time series data of said filter differential pressure collected by said data collector; and

a lifespan estimator which estimates the lifespan of said hydraulic pump based on said correlative relationship determined by said correlative relationship determining unit.

16. A hydraulic pump health monitoring system for a hydraulic machine, comprising a hydraulic pump, a drain filter which captures contaminants included in operating oil which flows to a drain of said hydraulic pump, a differential pressure sensor which measures a filter differential pressure across said drain filter, and a temperature sensor which measures the temperature of said operating oil, comprising:

a data collector which collects time series data of said filter differential pressure from said differential pressure sensor;

a correlative relationship determining unit which determines a correlative relationship between the lapse time over a specified long period of time and said filter differential pressure based on said time series data of said filter differential pressure collected by said data collector; and

a judgment unit which determines a degree of deviation between said long-term correlative relationship determined by said correlative relationship determining unit and said filter differential pressure data over a specified recent short period of time, and estimate the lifespan or judge said hydraulic pump abnormalities based on said determined degree of deviation.