Device and Method for State Monitoring in Hydrostatic Displacement Units

• US 20090229456A1
• Filed: 12/12/2006
• Published: 09/17/2009
• Est. Priority Date: 12/13/2005
• Status: Active Grant

• Current Assignee: Brueninghaus Hydromatik GmbH (Robert Bosch GmbH)
• Original Assignee: Brueninghaus Hydromatik GmbH (Robert Bosch GmbH)
• Inventors: Kunze, Thomas, Eichner, Wilfried
• Granted Patent: US 7,860,683 B2
• Time in Patent Office: Days
• US Class Current: 91/1
• CPC Class Codes: F04B 1/34 Control not provided for in groups F04B1/02, F04B1/03, F04B1/06 or F04B1/26
• CPC Class Codes: F04B 2201/0802 Vibration
• CPC Class Codes: F04B 2201/12051 Angular position
• CPC Class Codes: F04B 2205/05 Pressure after the pump outlet
• CPC Class Codes: F04B 51/00 Testing machines, pumps, or pumping installations
• CPC Class Codes: F04C 2270/80 Diagnostics

Abstract

The invention relates to a device (1) for state monitoring in hydrostatic displacement units (2), in particular in axial piston machines (3) operated as a pump or as a motor. The device (1) comprises an acquisition unit (4) with a multiplicity of sensors (5) which are attached to the hydrostatic displacement unit (2) and serve to acquire monitoring data (6) and operating data (7), and an evaluating unit (8) which has a device (9) for analysing the monitoring data in the frequency range and a device (10) for analysing the monitoring data in the time range. A diagnostic unit (11) with an output unit (13) is connected to the evaluating unit (8).

Claims

1. Device for state monitoring in hydrostatic displacement units, in particular in axial piston machines operated as a pump or as a motor, having an acquisition unit with a multiplicity of sensors which are attached to the hydrostatic displacement unit and serve to acquire monitoring data and operating data,

having an evaluating unit which comprises a device for analysing the monitoring data in the frequency range and a device for analysing the monitoring data in the time range,

and having a diagnostic unit, to which an output unit is connected.

2. Device for state monitoring according to claim 1,

wherein the device for analysing the monitoring data in the frequency range has a module for Fourrier transformation of the acquired monitoring data.

3. Device for state monitoring according to claim 1,

wherein the device for analysing the monitoring data in the time range has a module for assessing a trend behaviour using a quotient of actual value to a threshold value and/or a quotient of change of the actual value to a threshold value.

4. Device for state monitoring according to claim 1,

wherein at least three acceleration sensors connected to the acquisition unit are attached to a housing of the hydrostatic displacement unit.

5. Device for state monitoring according to claim 4,

wherein the acceleration sensors are attached to three different places on the housing of the hydrostatic displacement unit.

6. Device for state monitoring according to claim 4,

wherein the directions of the accelerations or vibrations to be measured by the three acceleration sensors are in each case perpendicular to one another in pairs.

7. Device for state monitoring according to claim 1,

wherein the hydrostatic displacement unit has cylinder bores which are arranged in a cylinder drum and have pistons axially movable in the cylinder bores, each piston being supported on an adjustable swash plate, and in that the operating data relate to a pressure in a high-pressure line and/or a pressure in a low-pressure line of the hydrostatic displacement unit, a pivot angle of the swash plate and/or a rotational speed of the cylinder drum.

8. Device for state monitoring according to claim 1,

wherein the monitoring data are obtained by the sensors provided at the corresponding places and are transmitted to the acquisition unit of the device for state monitoring.

9. Device for state monitoring according to claim 8,

wherein the monitoring data comprise the vibrations measured by three acceleration sensors.

10. Device for state monitoring according to claim 8,

wherein the monitoring data include the temperature determined by means of a sensor in a leak-oil line.

11. Device for state monitoring according to claim 8,

wherein the monitoring data include the temperature values, viscosity values and pressure values ascertained by means of a sensor mounted in a hydraulic fluid.

12. Device for state monitoring according to claim 8,

wherein the monitoring data include the temperature values ascertained by means of a temperature sensor mounted in a tank for the hydraulic fluid.

13. Device for state monitoring according to claim 8,

wherein the monitoring data include the contamination levels ascertained by means of a particle sensor mounted in the tank for the hydraulic fluid and/or by means of a particle sensor mounted in the leak-oil line.

14. Device for state monitoring according to claim 1,

wherein in the diagnostic unit there is a linkage of monitoring data to operating data, and there are definable threshold values for the monitoring data dependent on the operating data.

15. Device for state monitoring according to claim 1,

wherein a pre-alarm and a main alarm are provided in the output unit connected to the diagnostic unit, as alarm signals in relation to a machine state.

16. Device for state monitoring according to claim 15,

wherein the alarm signals in the output unit are acoustic signals.

17. Device for state monitoring according to claim 15,

wherein the alarm signals in the output unit are visual signals.

18. Method for state monitoring by means of a device in hydrostatic displacement units, in particular in axial piston machines operated as a pump or as a motor, having an acquisition unit with a multiplicity of sensors which are attached to the hydrostatic displacement unit and serve to acquire monitoring data and operating data, having an evaluating unit which comprises a device for analysing the monitoring data in the frequency range and a device for analysing the monitoring data in the time range, and having a diagnostic unit, to which an output unit is connected,

a multiplicity of sensors which acquire monitoring data and operating data in an acquisition unit being attached to the hydrostatic displacement unit, the monitoring data being analysed both in the frequency range and in the time range in the evaluating unit, and

a signal being output by the output unit connected to the diagnostic unit in dependence on the result of a preceding analysis.

19. Method for state monitoring according to claim 18,

wherein the sensors acquire monitoring data, such as surface vibrations and/or leak-oil and hydraulic-fluid temperature and/or hydraulic-fluid state, in particular contamination level.

20. Method for state monitoring according to claim 18,

wherein the acquired monitoring data, in particular the surface vibrations measured by means of at least three acceleration sensors, are Fourrier-transformed in the evaluating unit.

21. Method for state monitoring according to claim 18,

wherein the sensors acquire operating data, such as pressure in a high-pressure line and/or pressure in a low-pressure line and/or a pivot angle of a swash plate and/or a rotational speed of a cylinder drum.

22. Method for state monitoring according to claim 18,

wherein the quotient of an actual value and a defined threshold value is obtained in the device for analysing the monitoring data in the time range and/or frequency range.

23. Method for state monitoring according to claim 18,

wherein the quotient of a change of the actual value and a defined threshold value is obtained in the device for analysing the monitoring data in the time range and/or frequency range.

24. Method for state monitoring according to claim 22,

wherein a trend behaviour of the monitoring data is assessed in the time range and/or frequency range in the diagnostic unit using the quotients obtained in the evaluating unit.