JP2008082879A - Device and method for measuring torsional vibration - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply, easily and accurately measure fine torsional vibration with a simple constitution. <P>SOLUTION: A gear 13 is arranged on a rotation shaft 10, a detector 14 is arranged facedly to the gear 13, the detector 14 detects projections and depressions of the gear 13 in interlock with rotation and driving of the rotation shaft 10, a continuous reference detection signal corresponding to one rotation of the rotation shaft 10 in a non-excited state of torsional vibration is obtained, the period of the reference detection signal waveform is compared with the period of the same order of the continuous reference detection signal waveform corresponding to one rotation of the rotation shaft 10 in the excited state of torsional vibration, and the torsion angle displacement is determined for each time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a torsional vibration measuring apparatus and method used for measuring torsional angular displacement fluctuations of a rotating shaft of, for example, a large thermal turbine or a generator unit.

  In general, as this type of torsional vibration measuring device, various types of devices that measure the torsional vibration of a rotating body such as a rotating shaft using a non-contact type sensor have been proposed (see, for example, Patent Documents 1 and 2).

By the way, in such a torsional vibration measuring device, when measuring the torsional vibration displacement of the rotating shaft, a gear formed of a magnetic material such as a steel material is fitted and arranged on the rotating shaft as the detected portion. A known detector such as an electromagnetic pickup is disposed opposite to the tooth tip. In this detector, when the rotation shaft is driven to rotate, the tooth tips of the gears are sequentially opposed with the rotation, and an induced current is generated according to the difference in distance due to the unevenness, and the electric current is repeatedly increased and decreased. The signal is output as a detection signal waveform.
For example, as shown in FIG. 17, this detection signal waveform has a period (Ti) based on the rotational speed of the rotary shaft and the interval between the irregularities of the gears, and has a period difference corresponding to a slight difference in shape of the irregularities. This period (Ti) is calculated sequentially in sequence.

  For example, a fixed number of cycles (Ti) such as one rotation is weighted and averaged to obtain a reference cycle (T). When the torsional vibration is generated, a period (ti) different from the period (Ti) including the period of torsion is measured.

In addition, as a period (ti) and a reference period (T) of the detection signal waveform in a state to be measured, and a period (TN) of one rotation of the rotating shaft detected by another detector, for example, torsional angular displacement fluctuation (Δθi), That is, the rotational angular displacement fluctuation for obtaining the torsional vibration is: torsional angular displacement (Δθi) = (period of detection signal waveform (ti) −reference period (T)) / 1 period of rotation (TN) × 360 °
It is calculated based on the following formula.

In addition, a reference pulse generator is provided, and the reference period (T) is not calculated from the average of the periods (ti) of the detection signal waveform as shown in FIG. 18, but a constant period (Tp) corresponding to the number of gear teeth. There is a method in which the reference angular signal is generated and the rotational angular displacement fluctuation (Δθi) is calculated based on the reference period (Tp) and the period (ti) of the detection signal waveform.
In other words, the torsional angular displacement fluctuation is calculated based on the reference period (T) or constant period (Tp) of the detection signal waveform and the period (ti) of the detection signal waveform.
Japanese Patent Laid-Open No. 6-3078922 JP-A-2005-106638

  However, in the above torsional vibration measuring device, when the fluctuation of the torsional angular displacement of the rotating shaft is small and small compared to the amount of variation in the gear tooth spacing, the variation amount is obtained by a weighted average and the gear period. Since the torsional angle variation displacement amount is calculated from the period of the detection signal waveform corresponding to the tooth installation interval, the variation in the tooth interval is measured as torsional angular displacement variation, making accurate measurement difficult. Become.

For example, in a large-scale thermal turbine / generator unit, the torque acting on the generator suddenly changes during a power generation operation due to a sudden increase or decrease in load or a sudden change in load caused by a power transmission system failure. The torsional natural vibration may be excited in the entire turbine / generator shaft system including the turbine. In addition, in such a large thermal turbine / generator unit, the lowest order torsional natural vibration based on the distribution of the mass of the shaft system and torsional rigidity is about several Hz to several tens of Hz, which is based on the rotational speed. Some have a low frequency torsional natural frequency, and each natural vibration is excited by a sudden change in the load, and may vibrate according to the damping characteristics of the shaft system.
However, the length of the shaft system including this rotating shaft is 30 m, 40 m or more, and the torsion angle may reach several degrees between the front end and the rear end. The attenuation that hinders the torsional displacement fluctuation is about the attenuation of the material that constitutes the rotating shaft. If the damping speed of the vibration is relatively slow and the vibration continues for a long time, the rotating shaft is repeatedly fatigued. There is a risk of occurrence.
Therefore, in the large thermal turbine / generator unit, the rotational speed of the rotary shaft is calculated by assembling and arranging the torsional vibration measuring device on the rotary shaft system and calculating the period of the detection signal waveform. In addition, a method for measuring torsional vibration is employed.

  Here, the torsional vibration to be measured has a large torsional angular displacement, that is, the torsional vibration amplitude, and is not affected by its manufacturing accuracy, and its frequency is slower than the rotational speed of the rotating shaft. Thus, accurate measurement without measurement error is possible. For this reason, in the torsional vibration measuring apparatus, gears and detectors to be detected used for controlling or monitoring the rotational speed of the rotating shaft of the shaft system are diverted.

  In addition, since the vibration frequency is slower than the rotation speed of the rotating shaft, torsional vibration can be measured by continuously measuring the change in time required for one rotation. Without being affected by the installation accuracy of the object to be detected, it can be installed at one point on the circumference without using a gear having a plurality of teeth with irregularities, and its rotational period is measured. It is possible to measure accurately.

  However, in the large-scale thermal turbine / generator unit, during the power generation operation, a negative phase current is generated according to the state of the load of the electric motor connected to the terminal of the transmission system. Fluctuating torque having a frequency twice that of the power transmission system acts on the rotor of the generator. The rotor, that is, the rotating shaft is connected to a turbine shaft, which is a prime mover, and is rotationally driven via the prime mover. The turbine shaft includes blades that convert thermal energy of the fluid into rotational kinetic energy, and a rotating shaft system is configured by the generator shaft, the turbine shaft, the blades, and the fastening parts that connect these blades.

  The reverse phase current acts as a fluctuation torque having a frequency twice that of the power transmission system on the rotating shaft of the generator, that is, torsional excitation, and the rotating shaft system is excited to generate the torsional natural frequency of the shaft system. If they match, it will resonate and cause repeated fatigue. For this reason, it is important to ensure the reliability of the shaft system so that it does not have the natural frequency of the shaft system within the frequency range based on twice the frequency of electricity to be generated, that is, 100 Hz or 120 Hz. Yes, actual measurement verification is required.

However, in order to measure the torsional vibration having the same frequency as the rotational speed, it is necessary to install two or more objects to be detected on the surface of the rotating shaft. If it can be installed, accurate measurement of torsional vibrations is possible, but since it is actually difficult to install accurately, deviations occur in the period of the detection signal waveform, making accurate vibration measurement difficult. In addition, when the target torsional natural frequency is 100 Hz or near 120 Hz, the detection target placed on the circumference of the surface of the rotating shaft rotates because the frequency is more than twice the rotational speed. It is necessary to install four or more on the surface of the shaft. In this case, installation work becomes more difficult, and accurate vibration measurement becomes difficult.

  On the other hand, the amount of the reverse-phase current that acts on the rotating shaft of the generator is made to be as small as possible, and the transmission system is manufactured, and it changes every moment depending on the operating condition of the load connected to the terminal of the transmission system. In this case, it is a minute amount. Therefore, even if the shaft system is vibrated by a reverse-phase current acting on the generator, unless it resonates significantly, the torsional vibration amplitude generated in the shaft system, that is, the torsional angular displacement fluctuation is very small. It is difficult to accurately measure the torsional natural frequency.

Therefore, with a large thermal turbine / generator unit disconnected from the power transmission system, the generator end of the generator is excited by grounding one line to generate reactive power. There is a confirmation test in which current is generated in the generator, the shaft system is torsionally excited, the torsional natural vibration is excited, and the actual torsional natural vibration is confirmed.
It is possible to measure with the above torsional vibration measuring device by generating a large amount of negative phase current and applying strong vibration. However, if a large torsional vibration occurs, the shaft system will repeatedly fatigue and fatigue repeatedly. Therefore, it is difficult to perform accurate measurement.

Therefore, a method of measuring minute torsional vibration having a frequency near twice that of the power transmission system by measuring a slight distortion fluctuation amount of about 0.0001% generated on the surface of the rotating shaft that is torsionally vibrating. It has been.
However, in the measurement method described above, a Wheatstone bridge composed of a plurality of strain gauges is installed on the surface of the rotating shaft, and a power source for applying a voltage to the Wheatstone bridge is connected and arranged, and the detected strain fluctuation signal is transmitted. Since a transmission device for transmission has to be provided, the device is complicated and very large, and the assembly work to the thermal turbine / generator unit is very troublesome.

  The present invention has been made in view of the above circumstances, and a torsional vibration measuring apparatus and method capable of realizing simple and easy high-accuracy measurement of minute torsional vibrations with a simple configuration. The purpose is to provide.

  The present invention provides a detected part that is arranged around the axis of a rotating shaft and is rotated integrally with the detected part, and is arranged to be opposed to the detected part and is rotated integrally with the rotating shaft. Detecting means for detecting a part and outputting a detection signal; and a detection signal waveform for one rotation of the rotating shaft detected by the detecting means in a state where torsional vibration is not applied to the rotating shaft. An arithmetic operation for calculating a torsional angular displacement fluctuation amount by comparing a period and a period of a detection signal waveform for one rotation of the rotating shaft detected by the detecting means in a state where torsional vibration is applied to the rotating shaft. And a torsional vibration measuring device.

  According to the above configuration, the period of the continuous detection signal waveform for one rotation of the rotating shaft in a state where the torsional vibration is not applied, and the continuous detection signal for one rotation of the rotating shaft in the state where the torsional vibration is applied. By calculating the torsional angular displacement by sequentially comparing the cycles in the same order of the waveforms, the torsional angular displacement fluctuation amount with respect to time can be calculated. Therefore, accurate torsional angular displacement fluctuations can be measured without being restricted by the placement accuracy of the detected portion, and highly accurate vibration characteristics such as torsional vibration amplitude and frequency can be obtained.

  In addition, the present invention is arranged around the axis of the rotation shaft, and the detected portion that is rotated integrally with the detection portion, and is arranged so as to face the detected portion, and is rotated integrally with the rotation shaft. Detection means for detecting a detected portion and outputting a detection signal; and detection signal for one rotation of the rotary shaft detected by the detection means in a state where torsional vibration is not applied to the rotary shaft A calculating means for calculating a torsional angular displacement fluctuation amount by comparing a waveform with a detection signal waveform for one rotation of the rotating shaft detected by the detecting means in a state where torsional vibration is applied to the rotating shaft; A torsional vibration measuring device was configured.

  According to the above configuration, the continuous detection signal waveform for one rotation of the rotating shaft in a state where the torsional vibration is not applied, and the continuous detection signal waveform for one rotation of the rotating shaft in the state where the torsional vibration is applied. By calculating the torsional angular displacement by comparison in order, the torsional angular displacement fluctuation amount with respect to time can be calculated. Therefore, accurate torsional angular displacement fluctuations can be measured without being restricted by the placement accuracy of the detected portion, and highly accurate vibration characteristics such as torsional vibration amplitude and frequency can be obtained.

  As described above, according to the present invention, there is provided a torsional vibration measuring apparatus and method which can realize a highly accurate measurement of minute torsional vibrations with a simple configuration and easily. be able to.

  Hereinafter, a torsional vibration measuring apparatus and method according to embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a torsional vibration measuring apparatus according to an embodiment of the present invention. A rotary shaft 10 which is a rotor of a large-scale thermal turbine / generator unit or the like has a bearing 12 on a support frame 11. It is installed so that it can rotate freely. And the gearwheel 13 which comprises a to-be-detected part is fitted by the end of this rotating shaft. A detector 14 such as an electromagnetic pickup, which constitutes a detecting means for the tooth tip, is disposed opposite to the gear 13 with a predetermined gap. As shown in FIG. 2, this detector 14 is attached to, for example, the support base 11 of the rotary shaft 10 using an attachment jig 15, and is connected to an arithmetic processing unit 16 constituting arithmetic means.
In the arithmetic processing unit 16, for example, as shown in FIG. 3, the output end of the detection unit 14 is connected to the one rotation period detection unit 161. This one-rotation period detector 161 is connected to the waveform period counter 162 and is constant during the change of the detection signal input via the detector 14 from a low voltage to a high voltage as shown in FIG. The period of the detection signal waveform corresponding to one rotation of the rotating shaft is calculated from the time interval crossing the threshold, and the voltage is output to the waveform period counter 162. The detection signal waveform may be a signal converted into a change in current.

  The waveform cycle counting unit 162 is connected to the movable contact a of the switch 163, obtains the cycle of the detection signal waveform, and outputs it to the movable contact a of the switch 163. The switch 163 has the fixed contact b connected to the input end of the reference waveform cycle storage unit 164 and the fixed contact c connected to one input end of the torsion angle calculation unit 165. The switch 163 is controlled to be switched by a control unit (not shown). For example, the movable contact a is switched to the fixed contact b while the torsional vibration is not applied to the rotary shaft 10, and the rotation is performed. In a state where torsional vibration is applied to the shaft 10, the setting is switched to the fixed contact c.

  The torsion angle calculation unit 165 is connected to the other input end of the reference waveform cycle storage unit 164 and the output end of the D / A conversion unit 166. The torsion angle calculation unit 165 is based on the reference detection signal waveform to which torsional vibration is not applied, which is stored in the reference waveform cycle storage unit 164, and the detection signal waveform after occurrence of torsional vibration input via the switch 163. The displacement is obtained as measurement data and output to the D / A converter 166. The D / A converter 166 performs digital / analog conversion on the input measurement data and converts it into analog data.

  The D / A conversion unit 166 of the arithmetic processing unit 16 is connected to, for example, first and second arithmetic units 171 and 172 of the analysis unit 17 that evaluates the life of the rotating shaft system. Each output terminal of the first and second arithmetic units 171 and 172 is connected to one input terminal of the first comparison processing unit 173, and the measurement part is based on the measurement data from the D / A conversion unit 166. The torsional angle displacement fluctuation and the torsional angle maximum value are calculated and output to the first comparison processing unit 173. In the first comparison processing unit 173, the output terminal of the first memory unit 174 is connected to the other input terminal, and the third arithmetic unit 175 is connected to the output terminal.

  The first memory unit 174 includes, for example, a turbine shaft, a generator shaft, blades attached to these rotating shafts, fastening bolts, Fluctuation stress of each part based on the vibration amplitude and frequency of each part of the shaft system, which is the torsional vibration characteristics for the excitation of a certain amount of torsional vibration based on the mass, torsional rigidity, and damping characteristics of the entire rotating shaft system such as nuts During operation, such as tensile stress generated by centrifugal force based on the rotational speed and diameter of the rotating shaft system, transmission torque according to the power generation output, torsional stress based on the rotating shaft shape, and compression and tensile stress based on thermal deformation of the rotating shaft The steady stress generated in each part of the rotating shaft system is stored.

  The first comparison processing unit 173 is stored in the first memory unit 174 based on the torsion angle displacement variation and the torsion angle maximum value data at the measurement site from the first and second arithmetic units 171 and 172. The torsional vibration response characteristic of the necessary part is selected from the torsional vibration response characteristic information of the entire rotation axis system of the characteristic data, and is output to the third calculation unit 175. The third calculation unit 175 calculates the torsional vibration response of the necessary part in the rotation axis system meter based on the torsional angle displacement fluctuation and torsion angle maximum value data in the measurement part and the torsional vibration response characteristics of the necessary part of the rotation axis system. calculate.

  One input terminal of the second comparison processing unit 176 is connected to the third calculation unit 175, and the second memory unit 177 is connected to the other input terminal of the second comparison processing unit 176. The The second memory unit 177 stores, for each member, member strength characteristic data such as fatigue strength, which is the strength of each member constituting the rotating shaft system, the number of repetitions, and the strength against steady stress, for example. .

  The second comparison processing unit 176 is connected to the life evaluation unit 178, and stored information stored in the second memory unit 177 based on the torsional vibration response of the necessary part of the rotating shaft system from the third calculation unit 175. The information on the necessary part of the rotating shaft system is selected from among the information and output to the life evaluation unit 178. The life evaluation unit 178 determines the rotation axis based on the torsional vibration response of the necessary part of the rotation axis system from the third arithmetic unit 175 and the recorded information of the members constituting the necessary part selected from the second memory unit 177. An assessment of the fatigue life of the necessary parts of the system is performed.

  In the above configuration, when measuring the torsional vibration, the unevenness (tooth tip and tooth root) of the gear 13 that rotates in conjunction with the rotational drive of the rotating shaft 10 in a state where the torsional vibration is not applied to the rotating shaft 10. It is detected by the detector 14. The detection signal detected by the detector 14 is input to the one-rotation period detection unit 161, and the detection signal waveform is set at the interval of the unevenness of the gear 13 for one rotation as described above. The corresponding period is continuously detected, and a continuous period of the detection signal waveform for one rotation is output to the waveform period counter 162. As shown in FIG. 4, the waveform period counting unit 162 sets the period (Ti) (ti) of the detection signal waveform of one rotation of the rotating shaft 10 to the next rotation with the position where the rotation pulse rises as the head of the teeth of the gear 13. The period until the pulse rises is calculated as one period (TN).

  The rotation pulse is arranged corresponding to the detected part for detecting the rotational speed (not shown) arranged at another position on the rotating shaft 10 and the detected part (not shown), for example. It is generated by a detection unit (not shown) that detects a detected part (not shown) that is rotated in conjunction with the rotation of the shaft 10.

  Here, the switch 163 is set so that the movable contact a is switched to the fixed contact b, and the period of the detection signal waveform for one rotation in the state where the torsional vibration obtained by the waveform period counting unit 162 is not excited is the reference detection. It is stored in the reference period storage unit 164 as the period (Ti) of the signal waveform.

  Next, for example, the generator end of the generator is grounded by one line, a negative phase current is generated, and the rotating shaft 10 is torsionally excited to excite the torsional vibration. Here, the detector 14 detects the unevenness (tooth tip and tooth root) of the gear 13 that rotates integrally with the rotation of the rotating shaft 10 and outputs a detection signal to the one-rotation period detection unit 161.

  The one-rotation period detection unit 161 uses the input detection signal as a threshold value during the change from a low voltage to a high voltage, for example, and takes one rotation of the rotary shaft 10 from the time interval crossing the threshold value. The detection signal waveform period is calculated and output to the waveform period counter 162. The waveform period counting unit 162 similarly determines the period (ti) of the detection signal waveform of one rotation of the rotating shaft 10 until the position where the rotation pulse rises is the leading edge of the teeth of the gear 13 and the next rotation pulse rises. Calculated as a period (TN).

Here, the switch 163 is configured so that the movable contact a is switched to the fixed contact c, and the continuous period of the detection signal waveform for one rotation (when the torsional vibration obtained by the waveform period counting unit 162 is vibrated ( ti) is input to the torsion angle calculation unit 165. The torsion angle calculation unit 165 calculates the period (ti) of the input detection signal waveform and the period (Ti) of the reference signal waveform stored in the reference period storage unit 164 in the same order.
Torsional angular displacement (Δθi) = (period of detection signal waveform (ti) −period of reference detection signal waveform (Ti)) / 1 period of rotation (TN) × 360 °
The torsional angular displacement (Δθi) is calculated by performing the above calculation process, and the displacement of the torsional angular displacement (Δθi) is obtained every time (cycle) to calculate the torsional angular displacement fluctuation. As a result, even when the teeth of the gear 13 are non-uniform, accurate torsional angular displacement fluctuations are measured, and vibration characteristics such as highly accurate torsional vibration amplitude or frequency are calculated.
This measurement data is converted into analog data by the D / A conversion unit 166, and for example, as described above, the analysis unit 17 evaluates the fatigue life of the thermal turbine / generator unit or the like constituting the shaft system of the rotating shaft. Is called.

  As described above, the torsional vibration measuring device has the gear 13 on the rotating shaft 10, the detector 14 is disposed opposite to the gear 13, and the detector 14 is interlocked with the rotational drive of the rotating shaft 10. The unevenness of the gear 13 is detected, a continuous reference detection signal for one rotation of the rotary shaft 10 in a state where the torsional vibration is not applied is obtained, the period of the reference detection signal waveform and the torsional vibration are applied. The period of the same detection signal waveform for one rotation of the rotating shaft 10 in the shaken state is compared in the same order, and the torsional angular displacement is obtained at each time.

  According to this, since the torsional angular displacement fluctuation amount with respect to the time can be calculated based on the detection signal waveform, accurate measurement of the torsional angular displacement fluctuation is realized without being affected by the arrangement accuracy of the gear 10. As a result, it is possible to obtain vibration characteristics such as amplitude and frequency of torsional vibration with high accuracy with a simple configuration.

  The present invention is not limited to the above-described embodiment, but may be configured to measure torsional angular displacement as shown in FIG. 5, for example, and the same effect is expected. However, in FIG. 5, the same reference numerals are given to the same portions as those in the above embodiment, and the detailed description thereof is omitted.

  That is, the detector 14 detects a detection signal waveform based on the installation interval of the teeth of the gear 13 in one rotation of the rotary shaft 10 and outputs the detection signal waveform to the arithmetic processing unit 16. Here, the arithmetic processing unit 16 records the input detection signal, determines the amount of the detection signal, for example, the magnitude of the voltage or current, and the elapsed time from the reference time as a set, and the torsional vibration is vibrated. The detection signal in a state of not being recorded is recorded as a reference detection signal.

  The recording of the detection signal waveform is based on a rotation reference pulse (time) detected using a rotation speed detection target portion (not shown) arranged on the rotation shaft 10 and a rotation speed detection detection portion, for example. The amount of detection signal that changes with the passage of time, for example, the magnitude of voltage or current, and the elapsed time from the reference time are taken as a set until the rotation reference pulse that the detected part passes through the detection part next rises. It is done continuously.

  In the case of measuring torsional vibration with the above configuration, first, in a state where no torsional vibration is applied, the rotary shaft 10 is rotationally driven at the rotational speed to be measured, and one rotation is performed based on the rotational reference pulse. The detection signal of the minute is detected by the detector 14, and this is stored as the period (T2i) of the reference detection signal waveform.

  Subsequently, torsional vibration is applied to the rotating shaft 10 in the same manner as in the above-described embodiment, for example, and the amount of detection signal for one rotation and the elapsed time are determined based on the reference time and the period of the detection signal waveform (t2i). ) Continuously detected. Then, the amount of the detection signal and the same amount of the recorded reference detection signal are selected, and the elapsed time is reproduced based on the rotation reference pulse. This reproduction work includes the amount of detection signal, whether it has increased or decreased from the amount detected in the previous time, the ratio of the amount of change, and the detection signal for which the elapsed time is to be compared to a certain range The reference detection signal is selected using the determination condition as to whether or not it is present.

Next, an elapsed time from the rise of the rotation reference pulse of the selected reference detection signal, that is, a deviation time between the reference detection signal waveform period (T2i) and the detection signal waveform period (t2i) is obtained, and the rotation reference at that time is obtained. Based on the rotational speed calculated from the pulse period (TN), the torsional angular displacement (Δθ2i) in each period is calculated based on the rotational speed obtained from the rotational pulse period (TN). Period of detection signal waveform (t2i) −period of reference detection signal waveform (T2i)) / 1 period of rotation (TN) × 360 °
The torsional displacement fluctuation is calculated by performing this calculation process and performing this calculation process continuously for all the detection signal waveforms.

  According to this embodiment, since torsional angular displacement fluctuations are continuously calculated for each period of the detection signal, accurate torsional vibration can be measured without being similarly affected by the gear placement accuracy. Therefore, it is possible to obtain vibration characteristics such as amplitude and frequency of torsional vibration with high accuracy.

  Further, in the above-described embodiment, the present invention has been described with respect to the case where the detection means dedicated to the detection of the rotation pulse is provided to detect one rotation of the rotation shaft 10, but the present invention is not limited to this. As a plurality of detected objects constituting the detected part, at least one of the peripheral walls around the axis of the rotating shaft 10 has a waveform different from the others, for example, a voltage, for example, as shown in FIG. It is also possible to arrange such that the magnitude of the current, the voltage at a certain time, or the amount of change of the current is variable, so that one rotation of the rotating shaft 10 can be detected based on the different waveforms. A similar effect is expected. In this embodiment, a rotation pulse detection threshold is set for the amount of the detection signal waveform acquired during measurement, and the reference value on the rotary shaft 10 is passed when the threshold is reached. To determine the order or cycle of the cycles.

  Furthermore, this invention does not provide a detection means dedicated to detection of the rotation pulse as the detected part, and for example, a plurality of detected objects constituting the detected part are arranged on the peripheral wall around the axis of the rotary shaft 10. As shown in FIG. 7, at least one of them can be arranged to detect a different period compared to the other, and it is possible to detect one rotation of the rotary shaft 10 based on the different waveform. A similar effect is expected. In this embodiment, a rotation pulse detection threshold is set for the period of the detection signal waveform acquired during measurement, and the reference position on the rotary shaft 10 is passed with the period calculated. Judgment is made and the order of the cycles is obtained.

  In addition, the present invention is not limited to the above-described configuration, and the same effective effect can be expected even if the detected portion and the detection means are configured as shown in FIGS. 8 and 9. However, in FIG. 8 and FIG. 9, the same reference numerals are given to the same parts as those in the above-described embodiment, and the detailed description thereof is omitted.

  In this embodiment, a plurality of reflecting pieces 20 as reflecting members are arranged with a predetermined interval around the axis of the peripheral wall of the rotating shaft 10 as the detected portion, and the light irradiation device 21 and the light receiving device are used as the detecting means. The device 22 is disposed opposite to the support frame 11 with a predetermined gap with respect to the reflecting piece 20 of the rotating shaft 10 using the fixture 15. That is, in this embodiment, light is irradiated from the light irradiation device 21 toward the reflecting piece 20 of the rotating shaft 10 that is rotationally driven, the reflected light is detected by the light receiving device 22, and the light receiving device 22 receives the light. The converted light is photoelectrically converted by the photoelectric conversion unit 23 to generate an electric signal. Using this electrical signal as a detection signal waveform, the torsional angular displacement is calculated by the arithmetic processing as described above, and the torsional displacement fluctuation is obtained.

  Further, as the detected part, as shown in FIG. 10, the plurality of reflecting pieces 20 are provided on the adhesive tape 201, and the adhesive tape 201 is affixed to the rotating shaft 10 to attach the plurality of reflecting pieces 20. Even if it is arranged around the axis of the peripheral wall of the rotating shaft 10 and receives light reflected from the plurality of reflecting pieces 20 on the adhesive tape 201 and photoelectrically converts it to generate an electric signal, it is also effective. Expected.

  Further, as shown in FIG. 11, a high reflection region 241 with a large amount of reflected light such as white or metallic luster color, and a low reflection region 242 with a small amount of reflected light such as black or matte color are adhered as the detected portion. Arranged at random on the tape 201, the adhesive tape 201 is pasted around the axis of the peripheral wall of the rotating shaft 10, and similarly, the reflected light from the high reflection region 241 and the low reflection region 242 is received. It can also be configured to photoelectrically convert and generate an electrical signal, and similarly effective effects are expected. Even in this case, the high reflection region 241 and the low reflection region 242 may be arranged directly around the axis of the rotary shaft 10 without being arranged via the adhesive tape 201.

  Moreover, as a to-be-detected part, you may comprise as shown in FIG.12 and FIG.13 other than that, and the same effect is anticipated. However, in FIG.12 and FIG.13, the same code | symbol is attached | subjected about the same part as the said embodiment, and the description is abbreviate | omitted.

  In the embodiment shown in FIG. 12, in order to prevent thermal deformation of the rotating shaft before or after the rotating machine is started, the large gear 31 is fitted to the rotating shaft 30 of the turning device that is rotated about several revolutions per minute. As a detected part.

  In this embodiment, the detector 32 is attached to the housing 33 with a predetermined gap with respect to the tooth surface of the large gear 31 so as to face the toothed surface. The detector 32 is configured by using, for example, an electromagnetic sensor, and an induced voltage signal corresponding to a change in the clearance is obtained by sequentially passing through the uneven surface of the tooth surface in conjunction with the rotation of the large gear 31. As a result, the torsional angular displacement described above is calculated in the same manner using the induced voltage signal as a detection signal waveform, and the torsional angular displacement fluctuation is obtained.

  In addition, the detector 32 may be configured using an eddy current displacement sensor instead of the electromagnetic sensor. In the case of this eddy current type displacement sensor, an eddy current signal corresponding to the change in the gap is output in conjunction with the rotation of the large gear 31, and this eddy current signal is used as a detection signal waveform in the same manner as described above. The displacement is calculated and the torsional angular displacement variation is determined.

  In the embodiment shown in FIG. 13, for example, a fastening bolt / nut 42 used for connecting the shaft joint portion 41 of the rotating shaft 40 between the turbine shaft and the generator shaft is used as the detected portion.

  In the case of this embodiment, the fastening bolt and nut 42 constituting the detected portion is formed of a conductor such as steel or a magnetic material, so that the detector 43 can be an electromagnetic sensor (or eddy current displacement). Sensor) is disposed opposite to the housing 44 with a predetermined gap. The electromagnetic sensor (or eddy current type displacement sensor) constituting the detector 43 responds to the change in the clearance by passing through the fastening bolts and nuts 42 in order in conjunction with the rotation of the rotary shaft 40. An induced voltage signal (or eddy current signal) is output. The induced voltage signal (or eddy current signal) is used as a detection signal waveform, and the torsional angular displacement described above is calculated in the same manner to determine the torsional angular displacement fluctuation.

  Further, as the detected part, for example, the wall surface of the rotating shaft 10 (30, 40) is used to respond to a difference in reflection amount caused by aging due to minor corrosion of the wall surface or adhesion of lubricating oil. It is also possible to obtain a detection signal waveform, and the same effective effect is expected.

  In this embodiment, the light irradiating device 21 and the light receiving device 22 (see FIG. 8) are arranged to face each other with a gap in the wall surface of the rotating shaft 10 (30, 40), and light is emitted from the light irradiating device 21. Then, the light reflected by the wall surface of the rotating shaft 10 (30, 40) is received by the light receiving device 22, and the reflected light is photoelectrically converted to generate an electrical signal. Then, a detection signal waveform is obtained from this electrical signal based on a preset threshold value as shown in FIG. 14, and the above-described torsional angular displacement is calculated in the same manner based on this detection signal waveform. Angular displacement variation is required.

  Further, based on an accuracy error during machining that has occurred on the rotary shaft 10 (30, 40), the shaft perfect circle deviation within an allowable range due to a so-called minute runout, the rotary shaft 10 ( 30 and 40) can be configured such that the surface of the wall surface is detected as a detected portion, and an eddy current type displacement sensor is disposed opposite to the wall surface of the rotating shaft as a detection means. Be expected. This eddy current displacement sensor detects a minute gap change with the wall surface of the rotating shaft 10 (30, 40) and acquires a detection signal waveform based on a preset threshold value as shown in FIG. 14, for example. Then, based on this detection signal waveform, the above-described torsional angular displacement is similarly calculated, and the torsional angular displacement fluctuation is obtained.

  Here, in the above-described embodiment, the light irradiation device 21 irradiates light to the detected portion of the rotating shaft 10 (30, 40), the reflected light is received by the light receiving device 22, and the reflected light is photoelectrically converted. In the optical detection structure that converts and acquires the detection signal waveform, for example, as shown in FIG. 15, a method of recording the period of the reference detection signal waveform for one rotation of the rotating shaft 10 (30, 40) or the reference detection signal waveform. As described above, the amount of irradiation light may be changed in accordance with the cycle of one rotation so that a large feature appears at one position per rotation of the detection signal waveform or cycle. According to this method, the detection signal waveform for one rotation of the rotating shaft 10 (30, 40) is clearly defined, so that more accurate torsional angular displacement can be easily calculated.

  In addition, the present invention is not limited to the above-described embodiment. In addition, even if the detected portion and the detection means are configured as shown in FIG. However, in FIG. 16, the same parts as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, the rotating shaft 50 is formed in a hollow shape as the detected portion, and a plurality of transmission windows 501 orthogonal to the axial direction are formed around the axis of the peripheral wall at predetermined intervals, thereby detecting means. The light source 51 capable of projecting light radially is accommodated in the rotation shaft 50, and the light receiving device 52 is attached to the transmission window 501 of the rotation shaft 50 with a predetermined tool 15 with respect to the support frame 11. It is configured so as to face each other with a gap. The light receiving device 52 is sequentially opposed to the transmission window 501 of the rotation shaft 50 in conjunction with the rotation of the rotation shaft 50, and light from the light source 51 is received through the transmission window 501.

  With this configuration, in this embodiment, when light is emitted by driving the light source 51 in the rotational shaft 50 that is rotationally driven, the light is emitted off-axis through the transmission window 501 of the rotational shaft 50. At this time, the light receiving device 52 receives light emitted from the transmission windows 501 that are sequentially opposed with the rotation of the rotation shaft 50. The period of light emitted from the plurality of transmission windows 501 detected by the light receiving device 52 is a period according to the rotational speed of the rotating shaft 50 and the amplitude and period of torsional vibration. The light received by the light receiving device 52 is photoelectrically converted into an electric signal, and the electric signal is detected as a detection signal waveform, and the torsional angular displacement is calculated by calculating as described above to obtain the torsional displacement fluctuation. It is done.

  Therefore, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, the problems described in the column of problems to be solved by the invention can be solved, and the effects described in the effects of the invention can be obtained. In some cases, a configuration from which this configuration requirement is deleted can be extracted as an invention.

It is the arrangement block diagram shown in order to demonstrate the structure of the torsional vibration measuring apparatus which concerns on one embodiment of this invention. It is sectional drawing which showed the arrangement | positioning relationship between the gearwheel of FIG. 1, and a detector. FIG. 3 is a block diagram illustrating a configuration example of an arithmetic processing unit in FIG. 2. It is the wave form diagram shown in order to demonstrate the procedure which calculates | requires the cornering angle displacement calculated by the arithmetic processing part of FIG. It is the wave form diagram shown in order to demonstrate the calculation procedure of the torsion angle displacement which concerns on other embodiment of this invention. It is the wave form diagram shown in order to demonstrate the detection method for 1 rotation of the rotating shaft which concerns on other embodiment of this invention. It is the wave form diagram shown in order to demonstrate the other detection method for 1 rotation of the torsion rotating shaft which concerns on other embodiment of this invention. It is sectional drawing which extracted and showed the principal part of the torsional vibration measuring apparatus which concerns on other embodiment of this invention. It is the perspective view which showed the principal part detail of FIG. It is the perspective view which took out and showed the to-be-detected part of the torsional vibration measuring apparatus which concerns on other embodiment of this invention. It is the perspective view which took out and showed the to-be-detected part of the torsional vibration measuring apparatus which concerns on other embodiment of this invention. It is the perspective view which took out and showed the to-be-detected part of the torsional vibration measuring apparatus which concerns on other embodiment of this invention. It is the perspective view which took out and showed the to-be-detected part of the torsional vibration measuring apparatus which concerns on other embodiment of this invention. It is the wave form diagram shown in order to demonstrate the method of calculating | requiring a period from the detection signal waveform which concerns on other embodiment of this invention. It is the wave form diagram shown in order to demonstrate the other method of calculating | requiring a period from the detection signal waveform which concerns on other embodiment of this invention. It is sectional drawing which extracted and showed the to-be-detected part and detection means of the torsional vibration measuring apparatus which concerns on other embodiment of this invention. It is the wave form diagram shown in order to demonstrate the calculation procedure of the conventional torsion angle displacement. It is the wave form diagram shown in order to demonstrate the other example of the calculation procedure of the conventional torsion angle displacement.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Rotating shaft, 11 ... Supporting stand, 12 ... Bearing part, 13 ... Gear, 14 ... Detector, 15 ... Mounting jig, 16 ... Arithmetic processing part, 161 ... One rotation period detection part, 162 ... Waveform period counting part, 163: Switch, 164: Reference waveform cycle storage unit, 165 ... Torsion angle calculation unit, 166 ... D / A conversion unit, 17 ... Analysis unit, 171 ... First calculation unit, 172 ... Second calculation unit, 173 ... 1st comparison process part, 174 ... 1st memory part, 175 ... 3rd calculating part, 176 ... 2nd comparison process part, 177 ... 2nd memory part, 178 ... Life evaluation part, 20 ... Reflection piece 201 ... Adhesive tape, 21 ... Light irradiation device, 22 ... Light receiving device, 23 ... Photoelectric conversion unit, 241 ... High reflection region, 242 ... Low reflection region, 30 ... Rotating shaft, 31 ... Large gear, 32 ... Detector, 33 ... Housing, 40 ... Rotating shaft, 41 ... Shaft joint 42 ... fastening bolts and nuts, 43 ... detector, 44 ... housing, 50 ... rotary shaft, 501 ... transmission window, 52 ... light source, 52 ... light-receiving device.

Claims (16)

A to-be-detected part that is arranged around the axis of rotation and rotated together;
Detecting means for detecting the detected portion that is arranged to be opposed to the detected portion and that rotates together with the rotation shaft and outputs a detection signal;
In a state where no torsional vibration is applied to the rotating shaft, the period of the detection signal waveform for one rotation of the rotating shaft detected by the detecting means and torsional vibration is applied to the rotating shaft. In the state, the calculation means for calculating the torsional angular displacement fluctuation amount by comparing the period of the detection signal waveform for one rotation of the rotary shaft detected by the detection means;
A torsional vibration measuring apparatus comprising: A to-be-detected part that is arranged around the axis of rotation and rotated together;
Detecting means for detecting the detected portion that is arranged to be opposed to the detected portion and that rotates together with the rotation shaft and outputs a detection signal;
In a state where torsional vibration is not applied to the rotating shaft, a detection signal waveform for one rotation of the rotating shaft detected by the detecting means, and in a state where torsional vibration is applied to the rotating shaft Calculating means for calculating a torsional angular displacement fluctuation amount by comparing detection signal waveforms of one rotation of the rotating shaft detected by the detecting means;
A torsional vibration measuring apparatus comprising:   3. The torsional vibration measuring apparatus according to claim 1, wherein a plurality of the detected parts are arranged, and at least one of the detected parts is set to be able to detect a detection signal waveform different from the other.   The torsional vibration measuring apparatus according to claim 1 or 2, wherein a plurality of the detected parts are arranged, and at least one of the detected parts is set to be able to detect a period of a detection signal waveform different from the others.   The detected portion is composed of a plurality of reflecting members irradiated with light, and the detecting means irradiates the reflecting member with light, receives the reflected light and converts it into an electric signal, and The torsional vibration measuring device according to any one of claims 1 to 4, wherein a detection signal for one rotation is generated.   The torsional vibration measuring device according to claim 5, wherein the reflecting member is formed of a tape material in which a plurality of light reflecting portions are arranged at predetermined intervals and pasted around the rotation axis.   The torsional vibration measuring apparatus according to claim 6, wherein the light reflecting portion is formed of first and second light reflecting portions having different reflection amounts.   The detection target is configured by a gear fitted to the rotating shaft, and the detection unit is configured by an electromagnetic sensor disposed to face a tooth tip of the gear. 2. The torsional vibration measuring device according to 2.   The said detected part is comprised by the gear fitted by the said rotating shaft, and the said detection means is comprised by the overcurrent type displacement sensor arrange | positioned facing the tooth tip of the said gear. The torsional vibration measuring device according to 1 or 2.   10. The torsional vibration measuring device according to claim 8, wherein the detected portion includes a plurality of fastening bolts and nuts forming a shaft joint of the rotating shaft. 10.   The detected part is constituted by a peripheral wall surface of the rotating shaft, and the detecting means irradiates light to the peripheral wall surface of the rotating shaft, receives the reflected light and converts it into an electric signal, The torsional vibration measuring device according to claim 1 or 2, wherein a detection signal for one rotation is generated.   3. The detected part is constituted by a peripheral wall surface of a rotating shaft, and the detecting means is constituted by an overcurrent displacement sensor arranged to face the peripheral wall surface of the rotating shaft. The torsional vibration measuring device described.   12. The torsional vibration measuring device according to claim 5, wherein the light emitted from the detection means is variable in amount of irradiation with a period of one rotation of the rotation axis.   The detection means includes a light source disposed in the rotating shaft, and a plurality of transmission holes that transmit light from the light source are disposed on a peripheral wall of the rotating shaft, and the light transmitted through the transmission window is received to be electrically The torsional vibration measuring apparatus according to claim 1, wherein the torsional vibration measuring apparatus generates a detection signal for one rotation of the rotating shaft by converting into a signal.   15. The apparatus according to claim 1, further comprising an analysis unit that predicts a life by predicting a vibration response value of a shaft system formed by the rotating shaft based on a torsional angular displacement fluctuation amount calculated by the calculation unit. The torsional vibration measuring device according to any one of the above. A detection step of detecting a detected part arranged around the axis of the rotation axis in conjunction with the rotation of the rotation axis to obtain a detection signal;
In this detection step, the period of the detection signal waveform for one rotation of the rotating shaft acquired in a state where the torsional vibration is not applied to the rotating shaft, and the state in which the torsional vibration is applied to the rotating shaft A calculation step of calculating a torsional angular displacement fluctuation amount by comparing the cycles of the acquired detection signal waveform for one rotation of the rotating shaft;
A torsional vibration measuring method comprising:

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