METHOD FOR MONITORING A GEARED MOTOR, AND SYSTEM

Abstract

In a method for monitoring a geared motor, and a system, the geared motor has a gearbox at least partially filled with oil. A measure of the oil level, e.g., a measure of the filling-level height of the oil, is captured, and a measure of vibration is captured at at least one point of the gearbox. A first variable is formed by combining the measure of the oil level and the measure of vibration, and it is monitored whether the value of the first variable exceeds a permissible extent of deviation from a setpoint value or exceeds a threshold value.

Claims

1-15. (canceled)

16. A method for monitoring a geared motor that includes a gearbox at least partially filled with oil, comprising: measuring an oil level of the oil; measuring a vibration at at least one location of the gearbox; forming a first variable by combining the measurement of the oil level and the measurement of the vibration; and monitoring a value of the first variable for exceedance of a permissible extent of deviation from a setpoint value and/or a threshold value.

17. The method according to claim 16, wherein the measuring of the oil level includes measuring a filling-level height of the oil.

18. The method according to claim 16, wherein, in response to an exceedance, displaying and/or forwarding warning information.

19. The method according to claim 16, wherein, in response to an exceedance, performing an emergency shutdown of an electric motor supplied by an inverter and driving the gearbox.

20. The method according to claim 16, wherein, in response to an exceedance, activating a safe state of an electric motor supplied by an inverter and driving the gearbox.

21. The method according to claim 16, wherein the first variable is formed by division, as a quotient of the measure of vibration and the measure of the oil level.

22. The method according to claim 16, wherein the first variable is formed by division, as a quotient of a product, formed from the measurement of vibration and a measurement of temperature of the gearbox, and the measurement of the oil level.

23. The method according to claim 16, wherein the measurement of the vibration includes an average of a Fourier transformed temporal progression of the measurement of vibration.

24. The method according to claim 16, wherein the measurement of the vibration includes an average of a Fourier transformed temporal progression of the measurement of vibration in a frequency band.

25. A system, comprising: a gearbox; an inverter-fed electric motor adapted to drive the gearbox; a modular evaluation unit including evaluation modules, a central module, and a supply module; wherein the system is adapted to perform the method recited in claim 16.

26. The system according to claim 25, wherein the evaluation modules, the central module and the supply module are arranged in a row.

27. The system according to claim 25, wherein the supply modules is adapted to electrically supply the evaluation modules and the central module in parallel.

28. The system according to claim 25, wherein each evaluation module is electrically connected to a uniquely assigned respective sensor arranged on the gearbox.

29. The system according to claim 25, wherein each evaluation module includes a respective housing.

30. The system according to claim 25, wherein each evaluation module is connected to the central module by a wireless and/or wired data transmission channel.

31. The system according to claim 25, wherein the central module is adapted to combine sensor signals and to feed a result of the combined sensor signals to a monitor device that is connected to a display device adapted to display warning information and/or to device adapted to shut down the electric motor.

32. The system according to claim 25, wherein a first sensor is adapted to measure the oil level and/or to measure the oil level height of oil present in the gearbox.

33. The system according to claim 25, wherein a second sensor is adapted to measure the vibration of the gearbox.

34. The system according to claim 25, wherein a third sensor adapted to measure a temperature of the gearbox.

35. The system according to claim 34, wherein the third sensor includes an infrared sensor and/or is arranged within a housing part of the gearbox.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0026] FIG. 1 schematically illustrates a gearbox system according to an example embodiment of the present invention.

DETAILED DESCRIPTION

[0027] The gearbox has a housing part 1 in which bearings are accommodated for supporting shafts to which toothed parts are connected in a rotationally fixed manner.

[0028] The input shaft 2, e.g., the driving shaft, the input shaft, etc., is connected to the rotor shaft of an electric motor in a rotationally fixed manner or via a coupling.

[0029] The output shaft 6 can be connected to a load to be driven.

[0030] Sensors are arranged on or in the housing part 1, e.g., an oil level sensor 3 for capturing the oil level surrounded by the housing part 1, a temperature sensor 4 for capturing the temperature inside the housing part, and a vibration sensor 5, e.g., a structure-borne sound sensor, for capturing the mechanical, e.g., acoustic, oscillations of the housing part 1.

[0031] The signals of the sensors are fed to a modular-structured evaluation unit.

[0032] The evaluation unit has evaluation modules, a central module, and a supply module, which are arranged in a row. The evaluation modules and the central module are electrically supplied in parallel from the supply module.

[0033] The sensor signal of the oil level sensor 3 is fed to a first of the evaluation modules, the sensor signal of the temperature sensor 4 is fed to a second of the evaluation modules, and the sensor signal of the vibration sensor 5 is fed to a third of the evaluation modules.

[0034] The central module is connected to the evaluation modules by a data transmission channel.

[0035] The measured values captured and determined by the sensors and the evaluation modules are evaluated in the central module, in which a condition monitoring is carried out.

[0036] The measured values are monitored in the central module such that a warning signal and/or a shutdown signal is output if a permissible extent of deviation from a predefined range is exceeded.

[0037] For example, the shutdown signal causes the motor to be shut down, e.g., via an inverter feeding the motor, or activates a safe state of the electric motor. This does not necessarily have to be the stoppage of the rotor shaft but can also be a steady, e.g., uniform, rotation of the rotor shaft of the motor.

[0038] In the central module, the measured values determined by the evaluation modules are combined with each other and a monitoring is carried out in dependence thereon.

[0039] For example, a first variable can be formed which has the quotient of a product and of the captured level value of the oil level, and the product is determined from the captured temperature and from a vibration value captured by the vibration sensor.

[0040] As a value determined from the vibration values captured by the vibration sensor, the amplitude of a filtered-out frequency or the average amplitude of a frequency band is used as an example. Foe example, the signal of the vibration sensor 5 is fed to an FFT and from the Fourier spectrum thus determined for a frequency band a measure of the average amplitude and/or the integral over the amplitudes is formed in dependence on the frequency.

[0041] For example, if the oil level drops and thus the lubrication of the bearings and/or the meshing toothed parts deteriorates, the value determined from the vibration values captured by the vibration sensor increases, as does the friction of the meshing values.

[0042] Due to the formed combination, e.g., quotient and product formation, the first variable reacts extremely strongly. This is because a small drop in oil level can result in a small increase in vibration and temperature. However, multiplication and division result in a significant change of the value of the first variable. In this manner, a high sensitivity to a change is achieved.

[0043] For example, combinations that behave in a qualitatively similar manner mathematically can also be used.

[0044] Furthermore, the motor current can be captured by a sensor for capturing the motor current of the electric motor and the signals from this sensor can be fed to a further evaluation module. From there, values determined therefrom are fed to the central module, which combines these values determined in this manner from the captured motor current with values from other sensors, so that the result of the combining can be monitored for an impermissibly large extent of deviation from a permissible value.

[0045] For example, the RMS value, e.g., the root mean square value, of the Fourier transformed value progression captured by the vibration sensor 5 is formed, e.g., in a frequency band. From this, the quotient of this RMS value and the value determined from the signal of the oil level sensor 3 is formed and monitored for an impermissibly high extent of deviation from a threshold value. Thus, a variable that is very sensitive to changes caused by lubrication deterioration is accessible for monitoring.

LIST OF REFERENCE NUMERALS

[0046] 1 Housing part [0047] 2 Input shaft, e.g., driving shaft [0048] 3 Oil level sensor [0049] 4 Temperature sensor [0050] 5 Vibration sensor, e.g., structure-borne sound sensor [0051] 6 Output shaft