Vibration monitoring device, turbocharger, and vibration monitoring method

1 . A vibration monitoring device, comprising:

a rotation sensor for outputting a rotation signal synchronized with rotation of a rotational shaft;

an output device for outputting a filter command value that changes in accordance with changes in corresponding to a rotation speed of the rotational shaft calculated from the rotation signal; and

at least one filter for extracting, in response to input of the rotation signal and the filter command value, a signal in a passband set according to the filter command value from the rotation signal as a vibration signal from which vibration information of the rotational shaft can be obtained.

2 . The vibration monitoring device according to claim 1 ,

wherein the at least one filter includes a first low-pass filter, and

wherein the first low-pass filter extracts, in response to input of the rotation signal and the filter command value, a signal in a passband lower than a first cutoff frequency set according to the filter command value as the vibration signal.

3 . The vibration monitoring device according to claim 2 ,

wherein the at least one filter further includes a second low-pass filter having a second cutoff frequency lower than the first cutoff frequency.

4 . The vibration monitoring device according to claim 3 ,

wherein the second low-pass filter extracts, in response to input of the vibration signal extracted by the first low-pass filter, a signal in a passband lower than the second cutoff frequency from the vibration signal as a lifting signal from which lifting information of the rotational shaft can be obtained.

5 . The vibration monitoring device according to claim 1 ,

wherein the at least one filter includes a band-pass filter, and

wherein the band-pass filter extracts, in response to input of the rotation signal and the filter command value, a signal in a passband including a center frequency set according to the filter command value from the rotation signal as the vibration signal.

6 . The vibration monitoring device according to claim 5 ,

wherein 0.8C≤Fc≤1.2C is satisfied, where Fc is the center frequency, and C is the rotation speed of the rotational shaft.

7 . The vibration monitoring device according to claim 5 , further comprising a display part for displaying an amplitude of the vibration signal and a phase angle of the vibration signal with respect to the rotation signal, based on the rotation signal and the vibration signal extracted by the band-pass filter.

8 . The vibration monitoring device according to claim 1 ,

wherein the filter command value is a current value or a voltage value obtained by converting the rotation speed of the rotational shaft calculated from the rotation signal.

9 . The vibration monitoring device according to claim 1 ,

wherein the rotational shaft includes a marker portion configured such that the rotation signal has a pulse waveform.

10 . The vibration monitoring device according to claim 9 ,

wherein the marker portion includes at least two or more grooves formed on an outer peripheral surface of the rotational shaft, and

wherein the rotation sensor is an eddy current displacement sensor for detecting a distance to the outer peripheral surface of the rotational shaft by generating an eddy current on the outer peripheral surface of the rotational shaft.

11 . The vibration monitoring device according to claim 9 ,

wherein the marker portion includes at least two or more grooves formed on an outer peripheral surface of the rotational shaft, and

wherein the rotation sensor is a laser displacement sensor for detecting a distance to the outer peripheral surface of the rotational shaft by reflected light of a laser beam by irradiating the outer peripheral surface of the rotational shaft with the laser beam.

12 . A turbocharger, comprising:

the vibration monitoring device according to claim 1 ;

a compressor disposed on one end portion of the rotational shaft; and

a turbine disposed on another end portion of the rotational shaft.

13 . The turbocharger according to claim 12 , further comprising:

an acceleration sensor for detecting vibration of an engine; and

a display part for simultaneously displaying vibration information of the engine obtained from output of the acceleration sensor and vibration information of the rotational shaft obtained from the vibration signal extracted by the at least one filter.

14 . The turbocharger according to claim 12 , comprising:

a bearing rotatably supporting the rotational shaft;

a bearing temperature sensor for detecting a temperature of the bearing;

a lubricant oil outlet temperature sensor for detecting a temperature of lubricant oil outlet in the turbocharger; and

a display part for simultaneously displaying the temperature of the bearing detected by the bearing temperature sensor, the temperature of the lubricant oil outlet detected by the lubricant oil outlet temperature sensor, and vibration information of the rotational shaft obtained from the vibration signal extracted by the at least one filter.

15 . A vibration monitoring method, comprising:

a step of outputting a rotation signal synchronized with rotation of a rotational shaft;

a step of outputting a filter command value that changes in accordance with changes in corresponding to a rotation speed of the rotational shaft calculated from the rotation signal; and

a step of extracting, in response to input of the rotation signal and the filter command value, a signal in a passband set according to the filter command value from the rotation signal as a vibration signal from which vibration information of the rotational shaft can be obtained.

16 . A vibration monitoring device, comprising:

a rotation sensor for outputting a rotation signal synchronized with rotation of a rotational shaft;

an output device for outputting a filter command value corresponding to a rotation speed of the rotational

shaft calculated from the rotation signal; and

at least one filter for extracting, in response to input of the rotation signal and the filter command value, a signal in a passband set according to the filter command value from the rotation signal as a vibration signal from which vibration information of the rotational shaft can be obtained,

wherein the filter command value is a current value or a voltage value obtained by converting the rotation speed of the rotational shaft calculated from the rotation signal.