METHOD FOR MONITORING RAILWAY POINTS AND POINTS MACHINE

Abstract

Method for monitoring a track switch with a switch drive, wherein the switch drive includes a housing, a switch setting motor arranged in the housing and a switch rod extending out of the housing for coupling to a track switch. The method includes providing a piezoelectric sensor arranged on the housing and detecting measurement signals of the piezoelectric sensor during a switching operation of the switch drive. Periodic components of the measurement signal are at least partially filtered out in order to obtain signal components representative of a non-periodic change in the strain of the housing. The method also includes evaluating a temporal progression of the signal components representative of the non-periodic change in strain in order to identify deviations from a nominal state.

Claims

1-22. (canceled)

23. A method for monitoring a track switch with a switch drive, the switch drive including a housing, a switch setting motor arranged in the housing, and a switch rod extending out of the housing for coupling to a track switch, the method comprising: providing a piezoelectric sensor arranged on the housing; detecting measurement signals of the piezoelectric sensor, periodic components of the measurement signal being at least partially filtered out in order to obtain signal components representative of a non-periodic change in a strain of the housing, the detection of the signal components representing the non-periodic changes of the strain comprising a determination of quasi-static parts of the sensor pickup; and evaluating a temporal progression of the signal components representative of the non-periodic change in strain in order to identify deviations from a nominal state.

24. The method according to claim 23, wherein the measurement signals of the piezoelectric sensor are detected during a switching operation of the switch drive.

25. The method according to claim 23, wherein the piezoelectric sensor is arranged on an inner side of the housing.

26. The method according to claim 23, wherein the housing comprises a first housing component which at least partially surrounds the switch setting motor and a second housing component which is rigidly connected thereto and by which the switch drive is fastened to the track switch, and in that the piezoelectric sensor is arranged on the first housing component or on the second housing component.

27. The method according to claim 23, wherein the signal components representing the non-periodic change in strain are obtained by low-pass filtering, the low-pass filtering being carried out at a cutoff frequency at which periodic signal components of the piezoelectric sensor corresponding to a structure-borne sound are at least partially removed or attenuated.

28. The method according to claim 23, wherein the periodic signal components of the piezoelectric sensor comprise a frequency of >100 Hz.

29. The method according to claim 23, wherein the signal components representing the non-periodic change in strain are amplified by a charge amplifier.

30. The method according to claim 23, wherein an amplitude of the temporal progression of the signal components representing the non-periodic change in strain is determined and compared with a setpoint value.

31. The method according to claim 23, wherein a measure of the rough-running of the switch is determined from the signal components representing the non-periodic change in strain.

32. The method according to claim 23, wherein the temporal progression of the signal components representing the non-periodic change in strain is recorded during a plurality of switching operations and a maintenance requirement of the switch is determined from a comparison of the recorded progressions.

33. The method according to claim 23, wherein signal components of the piezoelectric sensor representing structure-borne sound waves are additionally detected and evaluated.

34. The method according to claim 23, wherein measured temperature values of a temperature sensor are detected which are representative of the temperature of the housing in the region of the piezoelectric sensor, and in that the measured temperature values are used to compensate for temperature-dependent changes in the measurement signals of the piezoelectric sensor.

35. A switch drive comprising: a housing; a switch setting motor arranged in the housing; a switch rod extending out of the housing for coupling to a track switch; a piezoelectric sensor arranged on the housing; and an evaluation unit to which the measurement signals of the piezoelectric sensor are fed, the evaluation unit configured to detect and record measurement signals of the piezoelectric sensor; wherein periodic components of the measurement signal are at least partially filtered out to obtain signal components representative of a non-periodic change in the strain of the housing; and wherein the evaluation unit is configured to detect the signal components representing the non-periodic change of the strain by determining the quasi-static parts of the sensor pickup, and the evaluation unit is configured to evaluate a temporal progression of the signal components representative of the non-periodic change in the strain to identify deviations from a nominal state.

36. The switch drive according to claim 35, wherein the measurement signals of the piezoelectric sensor are detected and recorded during a switching operation of the switch drive.

37. The switch drive according to claim 35, wherein the piezoelectric sensor is arranged on an inner side of the housing.

38. The switch drive according to claim 35, wherein: the housing comprises a first housing component which at least partially surrounds the switch setting motor and a second, plate-like housing component which is rigidly connected thereto and by which the switch drive can be fastened to the track switch; and the piezoelectric sensor is arranged on the first housing component or on the second housing component.

39. The switch drive according to claim 35, wherein a low-pass filter with a cutoff frequency is provided, at which periodic signal components of the piezoelectric sensor, corresponding to a structure-borne sound are at least partially removed or attenuated in order to obtain the signal components representing the non-periodic change in strain.

40. The switch drive according to claim 35, wherein the periodic signal components of the piezoelectric sensor comprise a frequency of >100 Hz.

41. The switch drive according to claim 35, wherein a charge amplifier is provided which amplifies the signal components representing the non-periodic change in strain.

42. The switch drive according to claim 35, wherein the evaluation unit is configured to determine an amplitude of the temporal progression of the signal components representing the non-periodic change in strain and to compare it with a setpoint value.

43. The switch drive according to claim 35, wherein the evaluation unit is configured to determine a measure of the rough-running of the switch from the signal components representing the non-periodic change in strain.

44. The switch drive according to claim 35, wherein the evaluation unit is configured to record the temporal progression of the signal components representative of the non-periodic change in the strain during a plurality of switching operations and to determine a maintenance requirement of the switch from a comparison of the recorded progressions.

45. The switch drive according to claim 35, wherein the evaluation unit is configured to additionally detect and evaluate signal components of the piezoelectric sensor which represent structure-borne sound waves.

46. The switch drive according to claim 35, further comprising a temperature sensor configured to detect a temperature of the housing in a region of the piezoelectric sensor, measured temperature values from the temperature sensor being fed to the evaluation unit for compensating for temperature-dependent changes in the measurement signals of the piezoelectric sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The invention is explained in more detail below with reference to embodiments shown schematically in the drawing. In this,

[0055] FIG. 1 shows the results of strain measurements,

[0056] FIG. 2 shows a first embodiment of a switch drive with a piezoelectric sensor and

[0057] FIG. 3 shows a second embodiment of a switch drive with a piezoelectric sensor.

DETAILED DESCRIPTION

[0058] FIG. 1 shows several curves corresponding to strains measured by a piezoelectric sensor on the housing of a switch drive during the changeover processes. The curve shown was obtained by filtering out high-frequency signal components of the piezoelectric sensor so that only the quasi-static components not induced by structure-borne sound remain. Progressions from a large number of changeover processes are shown one above the other.

[0059] The set of curves shown on the left in FIG. 1 corresponds to the changeover process in which the tongue rail is moved in one direction, and the set of curves shown on the right in FIG. 1 corresponds to the changeover process in which the tongue rail is moved in the opposite direction. Due to an optional magnitude formation step in the evaluation unit, the sensor signal deflections are shown as positive regardless of the direction of the changeover process for better comparability. It can be seen that the piezoelectric sensor arranged on the housing of the switch drive can be used to detect the typical load curve, which is characterized in the case of a fault-free switch by, among other things, a switch-on peak, a horizontal curve during the changeover of the switch and a steep drop after locking.

[0060] FIG. 2 shows a partial view of a switch drive 1 in cross-section. The switch drive 1 comprises a housing 2 in which a switch setting motor (not shown) is arranged, which drives a switch rod 3 extending out of the housing 2 for coupling to a track switch in the direction of the double arrow 4. The housing 2 also comprises a mounting plate 5 with which the switch drive 1 can be screwed onto a sleeper (not shown) via a drive bearing. A piezoelectric sensor 6 is attached to the inner side of the housing 2, namely to the side wall 7 of the housing 2, in order to detect changes in the strain of the housing 2.

[0061] FIG. 3 shows a partial view of a switch drive 1 from above. The switch drive 1 comprises a housing 2 in which a switch setting motor (not shown) is arranged, which drives a switch rod 3 extending out of the housing 2 for coupling to a track switch in the direction of the double arrow 4. The housing 2 further comprises a mounting plate 5, with which the switch drive 1 is fastened by means of fastening bolts 13 to a frame-like drive bearing, which comprises the frame components 8, 9, 10, 11 and 12. The drive bearing, in turn, is attached to the sleepers 15 by means of fastening bolts 14. In this embodiment, the piezoelectric sensor 6 is attached to the mounting plate 5, namely adjacent to the fastening bolts 13, in order to detect changes in the strain of the mounting plate 5 of the housing 2.