WEAR-MONITORING OF A GEARBOX IN A POWER STATION

• US 20140046614A1
• Filed: 03/09/2012
• Published: 02/13/2014
• Est. Priority Date: 03/11/2011
• Status: Active Grant

• Current Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Original Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Inventors: Pettersson, Bo
• Granted Patent: US 9,915,585 B2
• Time in Patent Office: Days
• US Class Current: 702/113
• CPC Class Codes: G01M 13/021 Gearings
• CPC Class Codes: G01M 13/04 Bearings
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

The invention relates to a method of monitoring a wear of a gearbox in a power station, such as a windmill, water-wheel or tidal power station, the gearbox comprising at least two shafts, cogwheels and bearings as components of the gearbox. The method comprises sensing an angular position at the shafts by a rotational shaft encoder and monitoring the wear of the transmission-unit according to differences of the sensed angular positions and generating a condition signal representative of the wear of the gearbox according to the monitored differences. The monitoring comprises an additional sensing of at least one additional degree of freedom, in particular an axial and/or eccentric displacement, of at least one of the shafts caused by wear of at least one of the components of the gearbox, and generating the condition signal according to the displacement and differences in the at least two degrees of freedom.

Claims

1-15. -15. (canceled)

16. A method of monitoring a wear of a gearbox in a power station comprising at least the following components:

at least a first shaft;

at least a second shaft;

cogwheels; and

bearings,

the method comprising;

sensing a first angular position, of the first shaft by a first rotational shaft encoder;

sensing a second angular position, of the second shaft by a second rotational shaft encoder;

monitoring the wear of the gearbox according to differences of the sensed angular positions of the first shaft and second shaft; and

generating a condition-signal representative of the wear of the gearbox according to the monitored differences,

wherein;

an additional sensing of a displacement of the first shaft and/or the second shaft in at least one additional degree of freedom; and

the displacement in the additional degree of freedom is comprised in the monitoring and generation of the condition-signal as an indication of wear.

17. The method according to claim 16, wherein the power station is a wind power station, a waterwheel power plant, or a tidal power plant.

18. The method according to claim 16, wherein the additional sensing of the displacement of the first shaft and/or the second shaft in at least one additional degree of freedom includes an axial and/or eccentric displacement caused by wear of at least one of the components of the gearbox.

19. The method according to claim 16, wherein the sensing of the angular position and of the displacement at one of the shafts is carried out by one single means, which is sensing in at least two degrees of freedom.

20. The method according to claim 19, wherein the one single means comprises:

a code carrier and a sensor arrangement, code carrier and sensor arrangement being rotatable relative to each other as a first degree of freedom;

and the sensing comprises;

generating a code projection, dependent on the three- dimensional displacement of the code carrier relative to the sensor arrangement, onto the sensor arrangement and detection of at least a part of the code projection;

determining the angular position of the code carrier from the code projection; and

determining a displacement value for the at least one additional degree of freedom of the code carrier relative to the sensor arrangement on the basis of the code projection.

21. The method according to claim 20, wherein an axial displacement of the sensor arrangement relative to the code carrier and/or the eccentricity of the sensor arrangement relative to the code carrier is determined

22. The method according to claim 16, wherein at least two angular positions at different axial locations on each of the first and/or second shaft are sensed and a twist of the respective shafts is determined.

23. The method according to claim 22, wherein the different axial locations are chosen so that a torque loaded shaft-section is in-between of the axial locations.

24. The method according to claim 23, wherein the torque load is determined dependent from the angular position differences and a known or presumed shaft stiffness.

25. The method according to claim 22, wherein the efficiency and/or losses of the gearbox are determined according to the sensed positions and/or displacements and the determined torque load.

26. The method according to claim 16, wherein the condition of the bearings is monitored according to a sensed axial and/or eccentric displacement of the shafts.

27. The method according to claim 16, wherein the condition of the bearings is monitored including a loose pre-stressing and/or a radial run-out of the bearings according to a sensed axial and/or eccentric displacement of the shafts.

28. The method according to claim 16, wherein each of the shafts in the gearbox are sensed with respect to their actual location and/or orientation in at least two degrees of freedom, in particular wherein an angular position and axial and/or eccentric displacements are sensed by the least one sensor on each of the shafts in the gearbox, preferably wherein the sensing is time synchronized.

29. The method according to claim 28, wherein an angular position and axial and/or eccentric displacements are sensed by the least one sensor on each of the shafts in the gearbox, preferably wherein the sensing is time synchronized.

30. The method according to claim 16, wherein an additional sound/vibration monitoring of the gearbox is performed.

31. The method according to claim 30, wherein he positional and displacement monitoring covers the lower frequency range of the evaluated wear indications and the sound/vibration monitoring covers the upper frequency range of the evaluated wear indications.

32. The method according to claim 16, wherein a managing of the lifespan of the gearbox according to the condition-signal and an allowable load condition to be applied to the gearbox is determined.

33. The method according to claim 32, wherein the managing of the lifespan of the gearbox according to the condition-signal includes an allowable load condition to be applied to the gearbox is determined by equalizing an expected lifespan of a plurality of power stations in a wind park.

45. A computer program product with program code being stored on a machine readable medium, the program code being configured to automatically execute and operate the method of monitoring a wear of a gearbox according to claim 16.

34. A gearbox monitoring device for power stations power plant gearbox, comprising

an angular shaft encoder for a first-shaft and

an angular shaft encoder for an second-shaft,

a calculation unit for monitoring a wear-condition of the gearbox according to signals of the angular shaft encoders, wherein at least one displacement sensor for determining displacements of a shaft of the gearbox in at least one translational degree of freedom, wherein the calculation unit is built in such a way as to determine the wear of the gearbox according to the signals of the angular shaft encoders and at least one signal from the at least one displacement sensor.

35. The device according to claim 34, wherein the calculation unit for monitoring a wear-condition of the gearbox according to signals of the angular shaft encoders does so by determining the difference of the signals of the at least two angular shaft encoders.

36. The device according to claim 34, wherein the at least one translational degree of freedom includes an axial or eccentric degree of freedom.

37. The device according to claim 34, wherein the angular shaft encoder and the displacement sensor are embodied as a single sensor, which is built in such a way to sense at least two degrees or freedom.

38. The device according to claim 37, wherein the wear-condition of the gearbox is determined according to the angular position signal and at least one axial position signal and/or excentric position signal from the single sensor.

39. The device according to claim 37, wherein further means for determining a torque-load signal of the gearbox and/or a synchronisation means for capturing the signals at a distinct time are comprised.

40. The device according to claim 34, wherein the first and/or second shaft has a further angular shaft encoder and a twist of the shaft is determined by the calculation unit according to the difference in relative angular position of the angular shaft encoders.

41. The device according to claim 40, wherein a torque load signal is generated by the calculation unit according to the twist and the shaft'"'"'s stiffness.

42. The device according to claim 34, wherein an intermediate-stage-shaft of the gearbox is equipped with a sensor, in particular all shafts are equipped with at least one sensor.

43. The device according to claim 42, wherein all shafts are equipped with at least one sensor.

44. A wear monitored gearbox system comprising a gearbox and a gearbox monitoring device according to claim 34.

46. The device according to claim 34, wherein the power stations include a wind-, waterwheel- or tidal-power plant.