Method for monitoring railway points and points machine
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.
1. 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.
2. The method according to claim 1 , wherein the measurement signals of the piezoelectric sensor are detected during a switching operation of the switch drive.
3. The method according to claim 1 , wherein the piezoelectric sensor is arranged on an inner side of the housing.
4. The method according to claim 1 , 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.
5. The method according to claim 1 , 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.
6. The method according to claim 1 , wherein the periodic signal components of the piezoelectric sensor comprise a frequency of greater than 100 Hz.
7. The method according to claim 1 , wherein the signal components representing the non-periodic change in strain are amplified by a charge amplifier.
8. The method according to claim 1 , 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.
9. The method according to claim 1 , wherein a measure of the rough-running of the switch is determined from the signal components representing the non-periodic change in strain.
10. The method according to claim 1 , 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.
11. The method according to claim 1 , wherein signal components of the piezoelectric sensor representing structure-borne sound waves are additionally detected and evaluated.
12. The method according to claim 1 , 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.
13. 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.
14. The switch drive according to claim 13 , wherein the measurement signals of the piezoelectric sensor are detected and recorded during a switching operation of the switch drive.
15. The switch drive according to claim 13 , wherein the piezoelectric sensor is arranged on an inner side of the housing.
16. The switch drive according to claim 13 , 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.
17. The switch drive according to claim 13 , 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.
18. The switch drive according to claim 13 , wherein the periodic signal components of the piezoelectric sensor comprise a frequency of greater than 100 Hz.
19. The switch drive according to claim 13 , wherein a charge amplifier is provided which amplifies the signal components representing the non-periodic change in strain.
20. The switch drive according to claim 13 , 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.
21. The switch drive according to claim 13 , 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.
22. The switch drive according to claim 13 , 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.
23. The switch drive according to claim 13 , wherein the evaluation unit is configured to additionally detect and evaluate signal components of the piezoelectric sensor which represent structure-borne sound waves.
24. The switch drive according to claim 13 , 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.