JP2014178145A - Vibration measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability of a vibration measurement device by measuring a vibration of a rotary body without contacting the rotary body.SOLUTION: The vibration measurement device includes a transmission antenna, a reception antenna and a measurement part. The transmission antenna transmits a measurement signal whose frequency sweeps towards the peripheral surface of a cylindrical rotary body which is rotatable around a rotation axis. The reception antenna receives the measurement signal reflected on the peripheral surface. The measurement part measures a vibration of the rotary body on the basis of a frequency difference between the frequency of the measurement signal transmitted and the frequency of the measurement signal received.

Description

  Embodiments described herein relate generally to a vibration measuring apparatus.

  As a technique for measuring the vibration of the rotating turbine shaft, the probe is brought into direct contact with the rotating turbine shaft, and the vibration of the turbine shaft is transmitted to an external vibration measuring instrument that is not integrated with the turbine shaft. Technology (hereinafter referred to as absolute vibration measurement technology), a technology for measuring vibration of a turbine shaft without contacting the turbine shaft (hereinafter referred to as “absolute vibration measurement technology”) and a cover member that supports the turbine shaft and covers the turbine shaft. Relative vibration measurement technology).

  Specifically, in the absolute vibration measurement technique, a probe that directly contacts the rotating turbine shaft is attached to a cover member that covers the turbine shaft, and the vibration of the turbine shaft is not integrated with the turbine shaft via the probe. This is transmitted to an external vibration measuring instrument (for example, an electrodynamic vibration meter). The electrodynamic vibrometer outputs a signal indicating the transmitted vibration of the turbine shaft to the converter. The signal output to the converter is subjected to signal processing (for example, integration processing or the like) and output to each instrument (for example, a recording device or a computer). Here, in the electrodynamic vibrometer, a movable part composed of a permanent magnet and a coil receives a vibration of a probe that is in direct contact with the turbine shaft and outputs a signal. This technique is called an absolute vibration measurement technique because the vibration of the turbine shaft can be measured without being influenced by the probe mounting state or the vibration measuring instrument installation state.

  Relative vibration measurement technology is required for non-contact vibration detectors that measure the gap between the turbine shaft and the non-contact vibration detector that are attached to the cover member and do not directly contact the turbine shaft. And a first converter for outputting a signal obtained by converting a gap measured by a non-contact vibration detector into vibration of the turbine shaft, and a cover member attached to the cover member itself. From an electrodynamic vibrometer that measures vibration and outputs a signal indicating the vibration of the cover member itself, a second converter that processes a signal output from the electrodynamic vibrometer, and a first converter The vibration of the turbine shaft is measured using a converter that extracts the vibration of only the turbine shaft from the output signal and the signal output from the second converter.

JP 2002-90447 A

  As described above, there are two types of techniques for measuring the vibration of the turbine shaft, that is, an absolute vibration measurement technique and a relative vibration measurement technique. In recent years, in order to improve the durability of the vibration measuring instrument, contactless In order to measure the vibration of the turbine shaft, there is an increasing demand for vibration measurement using a relative vibration measurement technique with little deterioration. However, according to the relative vibration measurement technique, if the phase difference between the signal output from the first converter and the signal output from the second converter is not considered, the signal output from the first converter There is a problem that it is impossible to extract only the vibration of the turbine shaft. The measurement of turbine shaft vibration in consideration of the phase difference between the signal output from the first converter and the signal output from the second converter is implemented by various calculation software. Compared with absolute vibration measurement technology due to the difference in the phase of the signal based on the vibration measurement results by each of the electrodynamic vibration meter and the non-contact vibration detector and the difference in responsiveness of the electrodynamic vibration meter. Therefore, the measurement result of the vibration of the turbine shaft lacks accuracy, and the measurement result of the vibration of the turbine shaft needs to be corrected.

  The vibration measurement device of the embodiment includes a transmission antenna, a reception antenna, and a measurement unit. The transmitting antenna transmits a measurement signal whose frequency is swept toward a peripheral surface of a cylindrical rotating body that is rotatable about a rotation axis. The receiving antenna receives the measurement signal reflected from the peripheral surface. The measurement unit measures the vibration of the rotating body based on the frequency difference between the frequency of the measurement signal to be transmitted and the frequency of the received measurement signal.

FIG. 1 is a side view showing a schematic configuration of the power plant according to the first embodiment. FIG. 2 is a front view illustrating a schematic configuration of a cover member included in the power plant according to the first embodiment. FIG. 3 is a diagram illustrating a configuration of a vibration measurement unit included in the vibration measurement apparatus according to the first embodiment. FIG. 4 is a diagram for explaining measurement of vibration by the vibration measurement unit according to the first embodiment. FIG. 5 is a diagram for explaining an antenna unit included in the vibration measurement apparatus according to the second embodiment. FIG. 6 is a diagram for explaining a shielding member included in the vibration measuring apparatus according to the third embodiment. FIG. 7 is a diagram for explaining an antenna unit and a shielding member included in the vibration measuring apparatus according to the first modification. FIG. 8 is a front view illustrating a schematic configuration of a cover member according to the fourth embodiment. FIG. 9 is a perspective view illustrating a schematic configuration of a probe included in the cover member according to the fourth embodiment. FIG. 10 is a perspective view illustrating a schematic configuration of a probe included in the cover member according to the fourth embodiment. FIG. 11 is a diagram illustrating a schematic configuration of a probe according to the fifth embodiment.

  Hereinafter, a power plant according to the present embodiment will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a side view showing a schematic configuration of the power plant according to the first embodiment. FIG. 2 is a front view illustrating a schematic configuration of a cover member included in the power plant according to the first embodiment. As shown in FIGS. 1 and 2, a power plant 1 according to the present embodiment includes a turbine 2 that rotates with high-temperature gas generated by combustion of fuel such as light oil, kerosene, and natural gas, A turbine shaft 3 that is a columnar rotating body that can rotate around a rotation shaft 32 by rotation, a cover member 4 that covers the turbine shaft 3, and a generator 5 that converts the rotation of the turbine shaft 3 into electric power, And a vibration measuring device 6 for measuring the vibration of the turbine shaft 3.

  The cover member 4 is a cover member that supports the turbine shaft 3 by a bearing or the like and covers the peripheral surface of the turbine shaft 3. As a result, the cover member 4 is integrated with the turbine shaft 3 and vibrates together with the turbine shaft 3. In the present embodiment, as shown in FIG. 2, the cover member 4 includes a first cover member 4 a that covers the upper half of the turbine shaft 3, and a second cover member 4 b that covers the lower half of the turbine shaft 3. Yes. The first cover member 4a is provided with at least an antenna unit 61 (described later) included in the vibration measuring device 6.

  The vibration measuring device 6 transmits a signal whose frequency is swept, and based on the frequency difference between the frequency of the signal to be transmitted and the frequency of the signal reflected by the measured object (the turbine shaft 3 in this embodiment). The vibration of the turbine shaft 3 is measured by using the principle of an FMCW (Frequency Modulated Continuous Wave) radar that obtains the distance to the object. In the present embodiment, the vibration measuring device 6 measures the vibration of the turbine shaft 3. However, the vibration measuring device 6 is not limited to this as long as it is rotatable around the rotating shaft 32 and is a cylindrical rotating body. For example, it is also possible to measure vibrations of a turbine included in a jet engine, a wheel of a train, a rotating component included in a pump, and the like. In the present embodiment, the vibration measuring device 6 measures the vibration of the rotating body, but it is also possible to measure the vibration of a pipe or the like.

  In the present embodiment, the vibration measuring device 6 is provided on the cover member 4 and transmits / receives a signal for measuring vibration of the turbine shaft 3, and the turbine shaft based on the signal transmitted / received by the antenna unit 61. 3 and a vibration measuring unit 62 that measures the vibration of No. 3.

  The antenna unit 61 includes a transmission antenna 611 that is provided on the cover member 4 and transmits a signal S having a frequency sweep (hereinafter referred to as a measurement signal) toward the peripheral surface 31 of the turbine shaft 3, and a turbine shaft that is provided on the cover member 4. And a receiving antenna 612 that receives the measurement signal S reflected by the peripheral surface 31 of the third. In the present embodiment, the transmission antenna 611 and the reception antenna 612 are provided along the outer periphery of a cross section orthogonal to the rotation shaft 32 of the turbine shaft 3, but are provided, for example, along the extending direction of the turbine shaft 3. May be. In this embodiment, the transmitting antenna 611 and the receiving antenna 612 are provided on the cover member 4, but the present invention is not limited to this, and the transmitting antenna 611 and the receiving antenna 612 may be supported by a support member separate from the cover member 4. good.

  The vibration measurement unit 62 is a measurement unit that measures the vibration of the turbine shaft 3 based on the frequency difference between the frequency of the measurement signal S transmitted from the transmission antenna 611 and the frequency of the measurement signal S received by the reception antenna 612. is there. Thereby, since the vibration of the turbine shaft 3 can be measured without contact with the turbine shaft 3, the durability of the vibration measuring device 6 can be improved.

  Here, a specific configuration of the vibration measuring unit 62 will be described with reference to FIGS. 3 and 4. FIG. 3 is a diagram illustrating a configuration of a vibration measurement unit included in the vibration measurement apparatus according to the first embodiment. FIG. 4 is a diagram for explaining measurement of vibration by the vibration measurement unit according to the first embodiment.

  In the present embodiment, the vibration measuring unit 62 includes an FM signal source 621, a directional coupler 622, a mixer 623, a signal processing unit 624, and an amplifier 625. The FM signal source 621 generates a measurement signal S whose frequency is swept. In this embodiment, the FM signal source 621 generates a measurement signal S that shifts by a predetermined frequency difference ΔF within a preset modulation period T and outputs the measurement signal S to the directional coupling unit 622 as shown in FIG. .

  The directional coupler 622 distributes the measurement signal S output from the FM signal source 621, outputs one measurement signal S to the mixer 623, and outputs the other measurement signal S to the transmission antenna 611.

  The amplifier 625 amplifies the measurement signal S received by the receiving antenna 612 and outputs it to the mixer 623.

  The mixer 623 receives the measurement signal S output from the directional coupler 622 (in other words, the measurement signal S transmitted from the transmission antenna 611) and the measurement signal S amplified by the amplifier 625 (in other words, received by the reception antenna 612). A signal (hereinafter referred to as a beat frequency signal) indicating a beat frequency Fb (shown in FIG. 4) that is a frequency difference between the measured signal S) and the measured signal S) is generated and output to the signal processing unit 624.

  The signal processing unit 624 calculates the distance to the turbine shaft 3 based on the beat frequency Fb indicated by the beat frequency signal output from the mixer 623, and measures the vibration of the turbine shaft 3 according to the calculated distance. Specifically, the signal processing unit 624 performs fast Fourier transform on the beat frequency signal output from the mixer 623, transmits the measurement signal S, and then reflects the signal on the peripheral surface 31 of the turbine shaft 3. Time τ until returning (hereinafter referred to as round trip time) is obtained.

The predetermined frequency difference ΔF and modulation period T, and the round-trip time τ and beat frequency Fb have the relationship shown in Expression (1).
Fb / τ = ΔF / T (1)
Further, the round-trip time τ, the speed of light c (3 × 10 ⁸ m / S), and the distance R (m) to the turbine shaft 3 have the relationship shown in the equation (2).
R = (c · τ) / 2 (2)
Therefore, according to Formula (1) and Formula (2), the relationship between the distance R to the turbine shaft 3 and the beat frequency Fb is Formula (3).
Fb = (ΔF · 2 · R) / (T · c)
That is, R = (T · c · Fb) / (2 · ΔF) (3)

  According to equation (3), the beat frequency Fb shown in FIG. 4 decreases as the distance R to the turbine shaft 3 decreases, and the beat frequency Fb illustrated in FIG. 4 increases as the distance R from the turbine shaft 3 increases. Become. Therefore, the signal processing unit 624 can measure the vibration of the turbine shaft 3 by monitoring the calculation result of the distance R with the turbine shaft 3.

  The resolution of the calculation result of the distance R with respect to the turbine shaft 3 depends on a predetermined frequency difference ΔF for sweeping the frequency of the measurement signal S within the modulation period T. The larger the predetermined frequency difference ΔF is, the larger the predetermined frequency difference ΔF is. The resolution of the calculation result of the distance R can be improved.

  Next, the difference between the method for measuring the vibration of the turbine shaft 3 by the conventional vibration measuring device and the method for measuring the vibration of the turbine shaft 3 by the vibration measuring device 6 according to the present embodiment will be described.

  Conventionally, as a technique for measuring a distance (vibration of the turbine shaft 3) attached to the cover member 4 without directly contacting the turbine shaft 3, a current is applied to the sensor coil attached to the cover member 4. A magnetic field is generated around the sensor coil, and the distance between the turbine shaft 3 and the cover member 4 (vibration of the turbine shaft 3) is determined from the change in eddy current generated when the turbine shaft 3 approaches the magnetic field. ) (So-called eddy current displacement meter).

  However, in the eddy current displacement meter, the frequency at which the vibration of the turbine shaft 3 can be measured is lower than the frequency of the vibration of the cover member 4 that supports the turbine shaft 3. If the cover member 4 vibrates between the time when the current is passed through the coil and before the distance between the turbine shaft 3 and the cover member 4 is measured, the vibration of the cover member 4 is reduced to the measured distance. Ingredients are included. Therefore, conventionally, the cover member 4 is provided with an electrodynamic vibrometer that measures the vibration of the cover member 4 itself, and the vibration of the turbine shaft 3 measured by the eddy current displacement meter and the electrodynamic vibrometer are measured. In consideration of the phase difference from the vibration of the cover member 4 and the vibration of the cover member 4 itself within the time required for the measurement of the vibration of the turbine shaft 3 by the eddy current displacement meter, it is measured by the eddy current displacement meter. The vibration of the turbine shaft 3 is acquired by subtracting the vibration of the cover member 4 measured by the electrodynamic vibrometer from the vibration of the turbine shaft 3.

  On the other hand, according to the vibration measuring apparatus 6 according to the present embodiment, the frequency of the measurement signal S swept by the frequency transmitted from the transmission antenna 611 and the reflection by the peripheral surface 31 of the turbine shaft 3 received by the reception antenna 612 are reflected. By measuring the vibration of the turbine shaft 3 based on the beat frequency Fb that is the frequency difference from the frequency of the measured signal S, the measurement signal S is transmitted from the transmission antenna 611 and then the cover is covered by the vibration of the cover member 4. Since the vibration of the turbine shaft 3 can be measured before the position of the member 4 changes (in other words, while the vibration of the turbine shaft 3 is being measured, it can be considered that the cover member 4 is not vibrating), The vibration of the turbine shaft 3 is measured without considering the vibration of the cover member 4 or the phase shift between the vibration of the cover member 4 and the vibration of the turbine shaft 3. Can.

  Thus, according to the vibration measuring device 6 of the first embodiment, the vibration of the turbine shaft 3 can be measured in a non-contact manner with respect to the turbine shaft 3, so that the durability of the vibration measuring device 6 is improved. Can do. Further, since the vibration of the turbine shaft 3 can be measured after the measurement signal S is transmitted from the transmission antenna 611 and before the position of the cover member 4 is changed due to the vibration of the cover member 4, the vibration of the cover member 4 can be measured. The vibration of the turbine shaft 3 can be measured without considering the phase shift from the vibration of the turbine shaft 3 and the vibration of the cover member 4.

(Second Embodiment)
In the present embodiment, the transmission antenna and the reception antenna are directional antennas, and the transmission antenna and the reception antenna are provided so that the positions where the gains of the main ropes of the transmission antenna and the reception antenna become maximum intersect on the peripheral surface of the turbine shaft. It is. In the following description, description of the same parts as those in the first embodiment is omitted.

  FIG. 5 is a diagram for explaining an antenna unit included in the vibration measurement apparatus according to the second embodiment. In the present embodiment, the antenna unit 501 includes directional antennas as the transmission antenna 502 and the reception antenna 503, and the transmission antenna 502 and the reception antenna 503 are angled with respect to the tangential direction of the peripheral surface of the turbine shaft 3. Provide. Thus, the transmitting antenna 502 and the receiving antenna 503 are provided so that the positions where the gains of the main ropes of the transmitting antenna 502 and the receiving antenna 503 are maximized intersect on the circumferential surface 31. In other words, the position where the radiation is maximized in the direction of the main rope of the transmitting antenna 502 and the position where the sensitivity is maximized in the direction of the main rope of the receiving antenna 503 are provided so as to intersect at the peripheral surface 31. Thereby, even if the measurement signal S is transmitted toward the peripheral surface 31 of the cylindrical turbine shaft 3, the measurement signal S reflected by the peripheral surface 31 is diffused, and the measurement signal S received by the receiving antenna 503 is reduced. Since it can prevent that S / N ratio falls, the vibration of the turbine shaft 3 can be measured more correctly.

  As described above, according to the second embodiment, since the S / N ratio of the measurement signal S received by the receiving antenna 503 can be improved, the vibration of the turbine shaft 3 can be measured more accurately.

(Third embodiment)
The present embodiment is an example in which a shielding member that is supported by a cover member and shields direct incidence of a measurement signal from a transmission antenna to a reception antenna is provided. In the following description, description of the same parts as those in the first embodiment is omitted.

  FIG. 6 is a diagram for explaining a shielding member included in the vibration measuring apparatus according to the third embodiment. In the present embodiment, the antenna unit 600 includes a shielding member that shields direct incidence of the measurement signal S from the transmission antenna 611 to the reception antenna 612 on the side where the peripheral surface 31 of the turbine shaft 3 of the antenna unit 600 is located. 601 is provided.

  Specifically, the shielding member 601 extends toward the peripheral surface 31 from the side where the peripheral surface 31 of the turbine shaft 3 of the antenna unit 600 is located, so that a measurement signal from the transmitting antenna 611 to the receiving antenna 612 is obtained. The direct incidence of S is shielded. Further, as the shielding member 601, a member capable of shielding the measurement signal S such as a ceramic substrate or an aluminum substrate is used.

  This prevents the measurement signal S from being directly incident on the reception antenna 612 from the transmission antenna 611 (prevents leakage of the measurement signal S from the transmission antenna 611 to the reception antenna 612). Since the S / N ratio of the received measurement signal S can be improved, the vibration of the turbine shaft 3 can be measured more accurately.

  In the present embodiment, the shielding member 601 is supported by the cover member 4 via the antenna unit 600 by being fixed to the side where the peripheral surface 31 of the turbine shaft 3 of the antenna unit 600 is located. For example, the cover member 3 may be directly fixed. Alternatively, the shielding member 601 may be supported by a support member that is separate from the cover member 3.

  Thus, according to the third embodiment, the leakage of the measurement signal S from the transmission antenna 611 to the reception antenna 612 is prevented, and the S / N ratio of the measurement signal S received by the reception antenna 612 is improved. Therefore, the vibration of the turbine shaft 3 can be measured more accurately.

(Modification 1)
In this modification, a transmitting antenna and a receiving antenna are provided at an angle with respect to the tangential direction of the peripheral surface of the turbine shaft, and are supported by a cover member to block direct incidence of measurement signals from the transmitting antenna to the receiving antenna. This is an example in which a shielding member is provided. In the following description, description of the same parts as those in the second and third embodiments is omitted.

  FIG. 7 is a diagram for explaining an antenna unit and a shielding member included in the vibration measuring apparatus according to the first modification. In this modification, the antenna unit 700 is provided with a transmission antenna 502 and a reception antenna 503 at an angle with respect to the tangential direction of the peripheral surface of the turbine shaft 3, and a range in which the measurement signal S can be transmitted by the transmission antenna 502. And a position where the transmission strength of the measurement signal S is higher than a preset transmission strength and a position where the reception strength of the measurement signal S is higher than a preset transmission strength in a range in which the measurement signal S can be received by the receiving antenna 503. Are made to intersect at the peripheral surface 31 of the turbine shaft 3.

  Further, the antenna unit 700 is provided with a shielding member 601 that shields the direct incidence of the measurement signal S from the transmitting antenna 611 to the receiving antenna 612 on the side where the peripheral surface 31 of the turbine shaft 3 of the antenna unit 700 is located. It has been.

  As a result, the measurement signal S is transmitted toward the peripheral surface 31 of the cylindrical turbine shaft 3 and the measurement signal S reflected by the peripheral surface 31 is diffused, and the measurement signal S directly from the transmission antenna 611 to the reception antenna 612 is transmitted. Can be prevented and the S / N ratio of the measurement signal S received by the receiving antenna 612 can be improved, so that the vibration of the turbine shaft 3 can be measured more accurately.

(Fourth embodiment)
This embodiment is an example in which the shielding member extends toward the peripheral surface of the turbine shaft and is provided at least away from the upper limit of the distance that the turbine shaft can vibrate in a direction orthogonal to the central axis of the turbine shaft. is there. In the following description, description of the same parts as those of the third embodiment is omitted.

  FIG. 8 is a front view illustrating a schematic configuration of a cover member according to the fourth embodiment. 9 and 10 are perspective views showing a schematic configuration of the probe provided in the cover member according to the fourth embodiment. The cover member 800 according to the present embodiment amplifies the probe 804 having the transmission antenna 611 and the reception antenna 612, the amplifier 802 that amplifies the measurement signal S transmitted from the transmission antenna 611, and the measurement signal S received by the reception antenna 612. The antenna unit 801 having the amplifier 803 to be supported is supported.

  As shown in FIG. 9, the probe 804 is an annular member made of a metal and a material excellent in oil resistance, and is directly fixed to the cover member 800. In this embodiment, the probe 804 is an annular member having an inner diameter L2 of about 40 to 50 mm and a total length of about 300 to 900 mm, as shown in FIG.

  The probe 804 extends toward the peripheral surface 31 of the turbine shaft 3, and at least an upper limit L1 (for example, 10 mm) of a distance at which the turbine shaft 3 can vibrate in a direction orthogonal to the rotation shaft 32 of the turbine shaft 3. A shielding member 805 provided at a distance is provided. The shielding member 805 shields direct incidence of the measurement signal S from the transmission antenna 611 to the reception antenna 612. Thereby, leakage of the measurement signal S from the transmission antenna 611 to the reception antenna 612 can be prevented with high accuracy, and the S / N ratio of the measurement signal S received by the reception antenna 612 can be improved.

  In FIG. 8 and FIG. 9, the shielding member 805 is continuously provided from one end of the probe 804 on the turbine shaft 3 side to the other end opposite to the one end. What is necessary is just to extend toward the surrounding surface 31 so that the direct incidence of the measurement signal S to the antenna 612 may be shielded. For example, as shown in FIG. 10, the shielding member 805 is provided with a shielding member 805 continuously from a position away from one end of the probe 804 on the turbine shaft 3 side to the other end opposite to the one end. good. Thereby, when the angle at which the measurement signal S is reflected on the peripheral surface 31 of the turbine shaft 3 varies, the reception rate of the measurement signal by the reception antenna 612 can be improved, so that the measurement signal received by the reception antenna 612 is improved. The S / N ratio of S can be improved.

  Thus, according to the fourth embodiment, leakage of the measurement signal S from the transmission antenna 611 to the reception antenna 612 is prevented with high accuracy, and the S / N ratio of the measurement signal S received by the reception antenna 612 is increased. Therefore, the vibration of the turbine shaft 3 can be measured more accurately.

(Fifth embodiment)
In this embodiment, an example in which a second shielding member that shields direct incidence of a measurement signal from the transmission antenna to the reception antenna is provided on the side opposite to the side where the turbine shaft is positioned with respect to the transmission antenna and the reception antenna. It is. In the following description, description of the same parts as in the fourth embodiment will be omitted.

  FIG. 11 is a diagram illustrating a schematic configuration of a probe according to the fifth embodiment. Fig.11 (a) is a perspective view which shows schematic structure of the probe concerning 5th Embodiment, FIG.11 (b) demonstrates the 2nd shielding member with which the probe concerning 5th Embodiment is provided. FIG. The probe 1100 according to the present embodiment is formed of a material such as a ceramic substrate or an aluminum substrate on the opposite side to the side where the peripheral surface 31 of the turbine shaft 3 of the transmission antenna 611 and the reception antenna 612 is located. A second shielding member 1101 that supports the receiving antenna 612 is provided. The second shielding member 1101 shields the direct incidence of the measurement signal S from the transmission antenna 611 to the reception antenna 612. Thereby, leakage of the measurement signal S from the transmission antenna 611 to the reception antenna 612 can be prevented with higher accuracy, and the S / N ratio of the measurement signal S received by the reception antenna 612 can be improved.

  As described above, according to the fifth embodiment, the leakage of the measurement signal S from the transmission antenna 611 to the reception antenna 612 can be prevented with higher accuracy, and the S / N ratio of the measurement signal S received by the reception antenna 612. Therefore, the vibration of the turbine shaft 3 can be measured more accurately.

  As described above, according to the first to fifth embodiments, the vibration of the turbine shaft 3 can be accurately measured.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

3 Turbine shaft 4,800 Cover member 6 Vibration measuring device 31 Peripheral surface 32 Rotating shaft 61,501,600,700 Antenna part 62 Vibration measuring part 601,805 Shielding member 611,502 Transmitting antenna 612,503 Reception antenna 1101 2nd Shielding member S Measurement signal

Claims (6)

A transmission antenna that transmits a measurement signal whose frequency is swept toward a peripheral surface of a cylindrical rotating body that is rotatable about a rotation axis,
A receiving antenna for receiving the measurement signal reflected by the peripheral surface;
Based on the frequency difference between the frequency of the measurement signal to be transmitted and the frequency of the received measurement signal, a measurement unit that measures the vibration of the rotating body,
Vibration measurement device with   The vibration measuring apparatus according to claim 1, wherein the transmitting antenna and the receiving antenna are provided on a covering member that supports the rotating body and covers the peripheral surface.   The vibration measuring apparatus according to claim 1, further comprising a shielding member that shields direct incidence of the measurement signal from the transmitting antenna to the receiving antenna.   The vibration measuring device according to claim 3, wherein the shielding member extends toward the peripheral surface and is provided at least away from an upper limit of a distance at which the rotating body can vibrate in a direction orthogonal to the rotation axis. .   The transmission antenna and the reception antenna are directional antennas, and are provided so that positions where the gains of the main ropes of the transmission antenna and the reception antenna become maximum intersect each other on the circumferential surface. The vibration measuring device according to any one of the above.   A second shielding member for shielding direct incidence of the measurement signal from the transmission antenna to the reception antenna is provided on the opposite side of the transmission antenna and the reception antenna from the side where the rotating body is located. The vibration measuring device according to any one of claims 1 to 5.

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