JP2005204415A - Detector and motor bearing abrasion detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing abrasion detector which detects the abrasion of a bearing, eliminating the influence due to the temperature of detecting coils A, R1, R2, R3, by detecting the position of a rotor in the state of operation stop of a canned motor and adjusting the zero point. <P>SOLUTION: A stator is provided with the detecting coils A, R1, R2, R3. This abrasion detector applies a high frequency signal, where DC at the same value as the effective value of a sine wave is superposed on this sine wave, from a high frequency power source 62 to the detecting coils A, R1, R2, R3. This detects a sine wave signal by means of sine wave signal detecting means 66 and 76, from the output of the detecting coils A, R1, R2, R3 where high frequency signals are applied, and detects DC resistance values with DC resistance value detecting means 67 and 77. This detects the inductance of the detecting coils A, R1, R2, R3 being obtained by subtracting the amount of the DC resistance value from the detected sine wave signal, by means of an inductance detection means 82. This detects the axial position of the rotor from the inductance of the detecting coils A, R1, R2, R3, by means of an axial position detecting means 83, and detects the radial position of the rotor by means of a radial position detecting means 84. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a detection device that detects the inductance of a detection coil and a bearing wear detection device that detects bearing wear of a motor.

  Conventionally, a canned motor has been mainly used for driving a pump. For example, in the case of a canned motor pump, the canned motor and the pump have a structure in which there is no liquid leakage. Cannot be monitored. The rotor of the canned motor that rotates the impeller of the pump is often supported by a bearing that is lubricated with the pump handling liquid. To efficiently operate this canned motor, the wear state of the bearing is monitored from the outside. There is a need to.

  Therefore, by providing detection coils at both axial ends of the stator of the canned motor and comparing the difference in voltage induced in the detection coils at both ends by the rotation of the rotor during operation, rotation supported by the bearing There has been proposed a bearing wear detection device that detects the axial position of a rotor and tries to estimate the axial bearing wear amount from the axial position of the rotor (see, for example, Patent Document 1).

  In addition, two radial position detection coils wound around the entire circumference of each tooth portion are provided on two tooth portions facing each other at 180 ° intervals of the stator of the canned motor, and the fundamental waves are mutually connected to the radial direction detection coils. Connected in series so as to cancel each other, and the radial position of the rotor supported by the bearing is detected by the voltage signal that is induced in both radial position detection coils by the rotation of the rotor during operation and the fundamental wave is canceled. Then, a bearing wear detection device has been proposed which tries to estimate the bearing wear amount in the radial direction from the radial position of the rotor (see, for example, Patent Document 2).

In addition, a position detection target that is a magnetic material is provided on the rotor or rotation shaft of the can motor, and a plurality of detection coils are circumferentially spaced around the stator can corresponding to the outer peripheral position of the position detection target. The high frequency signal is applied to the detection coil during the operation of the canned motor, the inductance of the detection coil to which the high frequency signal is applied is detected, and the rotor is detected from the change in the inductance of the detection coil. A position detection device that detects the axial position and the radial position of the sensor has been proposed (for example, see Patent Documents 3 and 4).
JP-A-9-233769 (page 3-4, Fig. 1-2) Japanese Patent Laid-Open No. 2000-308312 (page 3, FIG. 5) JP-A-8-43010 (pages 6-9, 17 and FIGS. 1-4, 20) JP 2001-505310 A (pages 21-23, FIG. 1-3)

  By the way, in the conventional bearing wear detection device, in order to accurately detect the axial position or radial position of the rotor from the voltage induced in the detection coil, the voltage signal induced in the detection coil and the rotation supported by the bearing are detected. Zero adjustment is required to match the axial position or radial position of the child. This zero point adjustment is an adjustment device for moving the rotor in the axial direction and the radial direction during the operation of the canned motor in a state where the rotor is rotated by the operation of the canned motor and the voltage is induced in the detection coil. Thus, the rotating rotor is moved to an arbitrary position in the axial direction or the radial direction, and the axial position or radial position of the rotor is made to correspond to the voltage induced in the detection coil.

  For this reason, the zero point adjustment is troublesome and takes time, and a factory having equipment capable of zero point adjustment is required because an adjustment device for moving the rotor in the axial direction or the radial direction during operation of the canned motor is required. If it is difficult to adjust the zero point at other locations where the canned motor is used, and the bearing or rotor needs to be replaced at the location where the canned motor is used, or if maintenance is required with additional gasket tightening, the location where the canned motor is used There is a problem that you have to bring it to the factory and adjust the zero point.

  Further, in the above-described position detection device, when the zero point is adjusted when the operation is stopped, the zero point cannot be adjusted unless the circumferential position of the position detection target is managed, and the gain is greatly reduced between the operation stop and the operation. Since it is different, accurate zero adjustment is difficult, and it is desirable to adjust the zero during operation. However, the zero point adjustment during operation has the above-mentioned problem as in the conventional bearing wear detection device.

  In this position detection device, a high-frequency signal is applied to the detection coil, the inductance of the detection coil to which the high-frequency signal is applied is detected, and the axial position and radial direction of the rotor are determined only from the change in the inductance of the detection coil. Because the position is detected, for example, when the DC resistance value of the detection coil changes due to changes in the temperature of the pump liquid, ambient temperature, and motor temperature, the inductance is affected by the change in the DC resistance value of the detection coil. Changes, and there is a problem that an error occurs in detecting the position of the rotor.

  The present invention has been made in view of the above points, and a detection device capable of detecting the accurate inductance of the detection coil by eliminating the influence of the temperature of the detection coil, and the position of the rotor when the operation is stopped. It is an object of the present invention to provide a motor bearing wear detection device that can detect and adjust the zero point, and can accurately detect the position of the rotor by eliminating the influence of the temperature of the detection coil.

  The detection device according to claim 1, wherein the detection device detects an inductance of the detection coil, and applies a high frequency signal in which a direct current of the same value as the effective value of the sine wave is superimposed on the sine wave to the detection coil. Application means, sine wave signal detection means for detecting a sine wave signal from the output of the detection coil to which the high frequency signal is applied, and DC resistance value detection means for detecting a DC resistance value from the output of the detection coil to which the high frequency signal is applied And inductance detecting means for detecting the inductance of the detection coil obtained by subtracting the DC resistance value detected by the DC resistance value detecting means from the sine wave signal detected by the sine wave signal detecting means. It is.

  In this configuration, a high frequency signal in which a direct current having the same value as the effective value of the sine wave is superimposed on the sine wave is applied to the detection coil, and the sine wave signal and the output from the detection coil to which the high frequency signal is applied Detects the DC resistance value and detects the inductance of the detection coil by removing the DC resistance value from the detected sine wave signal. Therefore, it is possible to detect the exact inductance of the detection coil without the influence of the temperature of the detection coil. become.

  A motor bearing wear detection device according to claim 2 is a high-frequency detection coil provided on the stator side of the motor, and a high frequency obtained by superimposing a direct current of the same value as the effective value of the sine wave on the detection coil. A high frequency signal applying means for applying a signal, a sine wave signal detecting means for detecting a sine wave signal from the output of the detection coil to which the high frequency signal is applied, and a DC resistance value is detected from the output of the detection coil to which the high frequency signal is applied. DC resistance value detecting means for detecting, and inductance detecting means for detecting the inductance of the detection coil obtained by removing the DC resistance value detected by the DC resistance value detecting means from the sine wave signal detected by the sine wave signal detecting means, And an axial position detecting means for detecting the axial position of the rotor of the motor from the inductance of the detection coil.

  In this configuration, a high frequency signal obtained by superimposing a direct current of the same value as the effective value of the sine wave on the sine wave is applied to the detection coil provided on the stator side of the motor, and the high frequency signal is applied. A sine wave signal and a direct current resistance value are detected from the output of the detection coil, respectively, and an inductance of the detection coil obtained by removing the direct current resistance value from the detected sine wave signal is detected, and the rotor of the motor is detected from the inductance of the detection coil. Because it detects the axial position of the rotor, the axial position of the rotor can be detected regardless of whether the motor is operating or stopped, so the rotor's axial position can be detected when the operation is stopped. Adjustment is possible, and the axial position of the rotor can be accurately detected by removing the influence of the temperature of the detection coil.

  A motor bearing wear detection device according to claim 3 is a detection coil provided on the stator side of the motor, and a high frequency in which a direct current of the same value as the effective value of the sine wave is superimposed on the detection coil. A high frequency signal applying means for applying a signal, a sine wave signal detecting means for detecting a sine wave signal from the output of the detection coil to which the high frequency signal is applied, and a DC resistance value is detected from the output of the detection coil to which the high frequency signal is applied. DC resistance value detection means for detecting, and inductance detection means for detecting the inductance of the detection coil obtained by removing the DC resistance value detected by the DC resistance value detection means from the sine wave signal detected by the sine wave signal detection means, And a radial position detecting means for detecting the radial position of the rotor of the motor from the inductance of the detection coil.

  In this configuration, a high frequency signal in which a direct current having the same value as the effective value of the sine wave is superimposed on a sine wave is applied to a detection coil provided on the stator side of the motor, and the high frequency signal is applied. A sine wave signal and a direct current resistance value are detected from the output of the coil, respectively, and an inductance of the detection coil obtained by removing the direct current resistance value from the detected sine wave signal is detected. From the inductance of the detection coil, the motor rotor is detected. Since the radial position is detected, the radial position of the rotor can be detected regardless of whether the motor is operating or stopped, so that the rotor's radial position can be detected when the operation is stopped and zero adjustment is performed. In addition, it is possible to accurately detect the radial position of the rotor by removing the influence of the temperature of the detection coil.

  According to the detection device of claim 1, a high frequency signal in which a direct current having the same value as the effective value of the sine wave is superimposed on a sine wave is applied to the detection coil, and the output of the detection coil to which the high frequency signal is applied. Since the sine wave signal and the DC resistance value are detected from the detected sine wave signal, and the detection coil inductance is detected by removing the DC resistance value from the detected sine wave signal, the influence of the temperature of the detection coil can be removed and detected. The exact inductance of the coil can be detected.

  According to the bearing wear detecting device for a motor according to claim 2, a high frequency signal obtained by superimposing a direct current of the same value as the effective value of the sine wave on a sine wave is applied to a detection coil provided on the stator side of the motor. Then, a sine wave signal and a direct current resistance value are detected from the output of the detection coil to which the high frequency signal is applied, and the inductance of the detection coil obtained by removing the direct current resistance value from the detected sine wave signal is detected. Since the axial position of the rotor of the motor is detected from the inductance of the detection coil, the axial position of the rotor can be detected regardless of whether the motor is operating or stopped. The direction position can be detected and the zero point can be adjusted, and the axial position of the rotor can be accurately detected by removing the influence of the temperature of the detection coil.

  According to the bearing wear detecting device for a motor according to claim 3, a high frequency signal obtained by superimposing a direct current of the same value as the effective value of the sine wave on a sine wave is applied to a detection coil provided on the stator side of the motor. Then, a sine wave signal and a direct current resistance value are detected from the output of the detection coil to which the high frequency signal is applied, and the inductance of the detection coil obtained by removing the direct current resistance value from the detected sine wave signal is detected. Since the radial position of the rotor of the motor is detected from the inductance of the coil, the radial position of the rotor can be detected regardless of whether the motor is operating or stopped. The position can be detected, the zero point can be adjusted, and the radial position of the rotor can be accurately detected by removing the influence of the temperature of the detection coil.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In FIG. 2, reference numeral 11 denotes a canned motor pump. The canned motor pump 11 is constituted by a canned motor 12 as a motor and a pump 13 which are integrally coupled in a liquid-tight manner.

  The canned motor 12 has a stator 17 formed by winding a stator winding 16 in a stator groove 15 of a stator iron core 14, and the stator 17 is inserted into a stator frame 18. At the same time, a stator can 19 formed in a thin cylindrical shape with a non-magnetic material such as stainless steel is closely attached to the inner peripheral surface of the stator 17, and both end edges of the stator can 19 are welded to the stator frame 18 in a liquid-tight manner. Has been. Reinforcing rings 20 and 21 for reinforcing the stator can 19 are mounted between the stator 17 and the stator frame 18 around the stator can 19.

  Further, the canned motor 12 has a rotor 25 configured by mounting a rotor conductor 24 in a rotor groove 23 of the rotor core 22, and this rotor 25 is inserted into a rotating shaft 26, and the rotor A rotor can 27 formed of a non-magnetic material such as stainless steel and having a thin cylindrical shape is attached to the outer peripheral surface of 25.

  A rotor 25 is inserted inside the stator 17, and a stator can 19 of the stator 17 and a rotor can 27 of the rotor 25 are disposed to face each other with a can gap 28 interposed therebetween.

  The stator frame 18 is provided with bearing housings 31 and 32 on the front side which is the pump 13 side and the rear side which is the opposite side, and a slide which rotatably supports the rotating shaft 26 on the bearing housings 31 and 32. Bearings 33 and 34 which are bearings are mounted. Sleeves 35 and 36 and thrust collars 37 and 38 for rotatably supporting the rotary shaft 26 are attached to the bearings 33 and 34, respectively. That is, the rotor 25 is rotatably supported by the bearings 33 and 34 via both sleeves 35 and 36, and is restricted by the thrust collars 37 and 38 and the bearings 33 and 34 in the axial direction.

  As shown in FIGS. 2 and 3, the axial position detection coil A is disposed along the outer periphery of the reinforcing ring 21, which is a container 41 in which the rotor 25 is located inside, on the rear side of the stator 17 of the canned motor 12. Is wound. The position where the axial position detection coil A is wound is the outer peripheral position of the rear end of the rotor 25.

  Of the plurality of tooth portions of the stator core 14 of the stator 17, three tooth portions positioned at equal intervals at an angular position of 120 ° are radially arranged over the entire circumference in the axial direction for each tooth portion. Position detection coils R1, R2, and R3 are wound respectively.

  The pump 13 also has a casing 51 that is liquid-tightly attached to the stator frame 18 of the canned motor 12 and an impeller 52 that is attached to the rotary shaft 26 in the casing 51. The impeller 52 in the pump 13 is rotationally driven by the rotor 25 supported by the bearings 33 and 34 via the sleeves 35 and 36, and its movement is restricted in the axial direction by the thrust collars 37 and 38 and the bearings 33 and 34. Has been.

  Next, FIG. 1 shows a circuit diagram of the bearing wear detector.

  Reference numeral 61 denotes a control circuit for the bearing wear detection device, to which one end of the axial position detection coil A and one end of each of the radial position detection coils R1, R2, and R3 are respectively connected. ing. The other end of the axial position detection coil A and the other end of the radial position detection coils R1, R2, and R3 are grounded to a common terminal.

  One end of the axial position detection coil A connected to the control circuit 61 is rotated by a drive of the canned motor 12 from a high frequency power supply 62 as a high frequency signal applying means, which is higher than the power supply frequency for driving the canned motor 12. A high-frequency signal, which is an alternating current signal in which a direct current of the same value as the effective value of the sine wave is superimposed on a sine wave higher than the harmonic signal generated in relation to the rotational speed of the rotor 25 and the number of grooves of the rotor 25, is applied. The One end of the axial position detection coil A is connected to the synchronous detector 64 through the high frequency circuit 63 and to the low frequency circuit 65.

  The high-frequency circuit 63 has a high-frequency filter such as a band-pass filter that passes only the sine wave signal from the output signal of the axial position detection coil A, and the synchronous detector 64 is a high-frequency signal obtained from the high-frequency power source 62. A sine wave signal synchronized with is extracted. The high frequency circuit 63 and the synchronous detector 64 are configured as sine wave signal detecting means 66 for detecting a sine wave signal from the output of the axial position detection coil A.

  The low-frequency circuit 65 has a low-frequency filter such as a low-pass filter, for example, and is configured as a DC resistance value detection means 67 that detects only a DC signal from the output of the axial position detection coil A and detects a DC resistance value. Yes.

  The sine wave signal from the synchronous detector 64 is amplified by the amplifier 68, and the DC resistance value signal from the low frequency circuit 65 is amplified by the amplifier 69 and input to the control device 70, respectively.

  One end of each of the radial position detection coils R1, R2, R3 connected to the control circuit 61 is connected to a changeover switch 72 for sequentially switching and connecting these radial position detection coils R1, R2, R3. ing. The change-over switch 72 shows a principle diagram in the figure, and is actually configured to be electrically switched in the circuit.

  A changeover switch 72 for sequentially switching and connecting the radial position detection coils R1, R2, and R3 is supplied from a high frequency power source 62 as a high frequency signal applying means, higher than a power source frequency for driving the canned motor 12, and driven by the canned motor 12. A high-frequency signal, which is an alternating current signal in which a direct current of the same value as the effective value of the sine wave is superimposed on a higher sine wave than the harmonic signal generated in relation to the rotational speed of the rotor 25 and the number of grooves of the rotor 25, is applied. Is done. The changeover switch 72 is connected to the synchronous detector 74 through the high frequency circuit 73 and to the low frequency circuit 75.

  The high-frequency circuit 73 has a high-frequency filter such as a bandpass filter that allows only the sine wave signal to pass from the output signals of the radial position detection coils R1, R2, and R3, and the synchronous detector 74 is supplied from the high-frequency power source 62. A sine wave signal synchronized with the obtained high frequency signal is extracted. The high-frequency circuit 73 and the synchronous detector 74 are configured as sine wave signal detection means 76 for detecting a sine wave signal from the outputs of the radial position detection coils R1, R2, and R3.

  The low-frequency circuit 75 has a low-frequency filter such as a low-pass filter, for example, and a DC resistance value detecting unit 77 that detects a DC resistance value by passing only a DC signal from the outputs of the radial position detection coils R1, R2, and R3. It is configured as.

  The sine wave signal from the synchronous detector 74 is amplified by the amplifier 78, and the DC resistance value signal from the low frequency circuit 75 is amplified by the amplifier 79 and input to the control device 70.

  The control device 70 detects the inductance of the axial position detection coil A and the radial position detection coils R1, R2, and R3 to which the high frequency signal is applied, and is detected by the sine wave signal detection means 66 and 76. Detection means for detecting the inductances of the axial position detection coil A and the radial position detection coils R1, R2, and R3 obtained by removing the DC resistance value detected by the DC resistance value detection means 67 and 77 from the received sine wave signal 82 function, the function of the axial position detection means 83 for detecting the axial position of the rotor 25 from the inductance of the axial position detection coil A, the radius of the rotor 25 from the inductance of the radial position detection coils R1, R2, R3 It has a function of radial position detecting means 84 for detecting the direction position.

  The control device 70 stores a program and data for detecting the axial and radial positions of the rotor 25 and detecting the wear state of the bearings 33 and 34, a reference value set by zero adjustment, and the like. 85, a display device 86 for displaying the wear state of the bearings 33 and 34 is connected.

  The control device 70 includes a zero point adjusting device 87 for adjusting a zero point to match the position of the rotor 25 with the output of the axial position detection coil A and the output of the radial position detection coils R1, R2, and R3 at the initial stage. A communication circuit 88 for communication and an output circuit 89 for outputting data such as wear signals to an external monitoring device or a computer are connected.

  Next, zero point adjustment for axial bearing wear detection in the bearing wear detector will be described.

  When the operation of the canned motor 12 is stopped, a high frequency signal is applied from the high frequency power source 62 to the axial position detection coil A, and the axial position detection coil A is excited to output an output signal corresponding to the position of the rotor 25. From the output of the axial position detection coil A, a sine wave signal synchronized with the high frequency signal obtained from the high frequency power source 62 is extracted by the high frequency circuit 63 and the synchronous detector 64, and a DC resistance value signal is extracted by the low frequency circuit 65. The extracted sine wave signal and DC resistance value signal are input to the control device 70.

  In this state, in order to adjust the zero point of the axial bearing wear, the rotor 25 is moved toward the rear side in the axial direction until the movement is restricted by the thrust collar 38 and the bearing 34, and the zero point adjusting device 87 The sine wave signal of the axial position detection coil A input to the control device 70, the DC resistance value signal, the inductance value obtained by subtracting the DC resistance value from the sine wave signal, etc. It is stored in the memory 85 as a reference value.

  Move the rotor 25 toward the front side in the axial direction until the movement is limited by the thrust collar 37 and the bearing 33, and operate the operation part of the zero adjustment device 87 to input the axial direction to the control device 70. A sine wave signal, a DC resistance value signal of the position detection coil A, an inductance value obtained by removing a DC resistance value from the sine wave signal, and the like are stored in the memory 85 as a reference value on the front side.

  The play value in the axial direction of the rotor 25 is input by the operation unit of the zero adjustment device 87 and stored in the memory 85.

  The temperature of the axial position detection coil A is measured with a thermometer, and the initial temperature value is input as a reference value at the operation unit of the zero adjustment device 87 and stored in the memory 85. If such initial adjustment is performed and a function for displaying and outputting the temperature is added, the detection coil temperature and display can be output.

  Next, zero point adjustment for radial bearing wear detection in the bearing wear detector will be described.

  When the operation of the canned motor 12 is stopped, each radial position detection coil R1, R2, R3 is sequentially switched by the changeover switch 72 and a high frequency signal is applied from the high frequency power supply 62, and each radial position detection coil R1, R2, R3 is connected. Energized to sequentially output an output signal corresponding to the position of the rotor 25. A sine wave signal synchronized with the high frequency signal obtained from the high frequency power supply 62 is extracted from the output of each radial position detection coil R1, R2, R3 by the high frequency circuit 73 and the synchronous detector 74, and the direct current resistance value is extracted by the low frequency circuit 75. Retrieve the signal. The extracted sine wave signal and DC resistance value signal are input to the control device 70.

  In this state, in order to adjust the zero point of radial bearing wear, the rotor 25 is moved in a predetermined direction such as the upper side in the radial direction until the movement is restricted by the bearings 33 and 34 and the sleeves 35 and 36. By operating the operation part of the zero adjustment device 87, the DC resistance is obtained from the sine wave signal, DC resistance value signal, and sine wave signal of each of the radial position detection coils R1, R2, and R3 that are sequentially input to the control device 70. The inductance value excluding the value is stored in the memory 85 as a rear reference value. Such processing is similarly performed for a plurality of radial directions.

  The play value in the radial direction of the rotor 25 is input by the operation unit of the zero adjustment device 87 and stored in the memory 85.

  Next, an axial bearing wear detection operation of the bearing wear detection device during operation of the canned motor pump 11 will be described.

  In an operating state of the canned motor 12, a high frequency signal is applied to the axial position detection coil A from the high frequency power source 62, and the axial position detection coil A is excited to output an output signal corresponding to the position of the rotor 25. From the output of the axial position detection coil A, a frequency other than the high frequency signal applied to the axial position detection coil A is cut by the high frequency circuit 63 and the synchronous detector 64 to synchronize with the high frequency signal obtained from the high frequency power source 62. Only the wave signal is taken out, and only the DC resistance signal is passed through the low frequency circuit 65 to take out the DC resistance value. The extracted sine wave signal and DC resistance value signal are input to the control device 70.

  Then, the control device 70 performs arithmetic processing from the input sine wave signal and DC resistance value signal to detect the axial bearing wear state of the bearings 33 and 34. The arithmetic processing of the control device 70 will be described with reference to the flowchart of FIG.

  The control device 70 reads each reference value stored in advance by zero adjustment from the memory 85 (step 1), acquires a sine wave signal that is a rotor position signal input to the control device 70 (step 2), A DC resistance value signal, which is a temperature correction signal input to the control device 70, is acquired (step 3).

  A change in impedance Z of axial position detection coil A is obtained from the sine wave signal (step 4), and a change in resistance value R of axial position detection coil A is obtained from the DC resistance value signal (step 5).

  A change in the inductance L of the axial position detection coil A is obtained by correcting the temperature by removing the change in the resistance value R from the impedance Z of the axial position detection coil A (step 6).

  Then, the inductance L of the axial position detection coil A is compared with a reference value to determine the axial wear state of the bearings 33 and 34 (step 7).

  A wear display signal corresponding to the wear state of the bearings 33 and 34 is transferred to the display device 86, the wear state is displayed on the display device 86 (step 8), and the normalized wear signal is output to the output circuit 89 (step). 9).

  FIG. 5 is a graph showing the output of the output circuit 89 when the rotor 25 moves rearward due to axial wear. The horizontal axis of the graph indicates the axial position of the rotor 25, and the vertical axis indicates the voltage of the wear signal output to the output circuit 89.

  Next, the radial bearing wear detection operation of the bearing wear detection device during operation of the canned motor pump 11 will be described.

  In the operating state of the canned motor 12, each radial position detection coil R1, R2, R3 is sequentially switched by the changeover switch 72 to apply a high frequency signal from the high frequency power supply 62, and each radial position detection coil R1, R2, R3 Are output in order according to the position of the rotor 25. From the output of the radial position detection coils R1, R2, and R3, the high frequency circuit 73 and the synchronous detector 74 cut frequencies other than the high frequency signal applied to the radial position detection coils R1, R2, and R3 and from the high frequency power supply 62. Only the sine wave signal synchronized with the obtained high frequency signal is taken out, and the low frequency circuit 75 passes only the signal corresponding to the direct current resistance to take out the direct current resistance value. The extracted sine wave signal and DC resistance value signal are input to the control device 70.

  Then, the control device 70 performs arithmetic processing from the input sine wave signal and DC resistance value signal to detect the radial bearing wear state of the bearings 33 and 34. The arithmetic processing of the control device 70 will be described with reference to the flowchart of FIG.

  The control device 70 reads each reference value stored in advance by zero adjustment from the memory 85 (step 11), acquires a sine wave signal that is a rotor position signal input to the control device 70 (step 12), A DC resistance value signal, which is a temperature correction signal input to the control device 70, is acquired (step 13).

Changes in impedances Z ₁ , Z ₂ , and Z ₃ of radial position detection coils R ₁ , R 2, and R ₃ are obtained from the sine wave signal (step 14), and the resistances of radial position detection coils R 1, R 2, and R ₃ are determined from the DC resistance value signal. Changes in values R ₁ , R ₂ , R ₃ are obtained (step 15).

Impedance _Z 1 of the radial position detection coils R1, R2, _R3, Z 2, by excluding from _{Z 3} to change in the resistance value _{R 1,} R 2, _{R 3} temperature correction, radial position detection coils R1, Changes in inductances L ₁ , L ₂ , and L ₃ of R2 and R3 are obtained (step 16).

Then, the inductances L ₁ , L ₂ , and L ₃ of the radial position detection coils R1, R2, and R3 are compared with a reference value to determine the radial wear state of the bearings 33 and 34 (step 17).

  A wear display signal corresponding to the wear state of the bearings 33 and 34 is transferred to the display device 86, the wear state is displayed on the display device 86 (step 18), and a normalized wear signal is output to the output circuit 89 (step). 19).

  FIG. 7 is a graph showing changes in the output of the axial wear signal and the radial wear signal when radial wear occurs. The horizontal axis of the graph represents time, and the vertical axis represents the wear signal voltage output to the output circuit 89. In a state where radial wear has occurred, the canned motor 12 is started and the pump 13 is loaded with the pump handling liquid (timing P), whereby the rotor 25 moves in the radial direction and the radial wear signal increases. However, the axial wear signal is not affected and remains substantially constant.

  Next, temperature correction will be described.

  By applying a high frequency signal superimposed on a sine wave to the axial position detection coil A and the radial position detection coils R1, R2, R3, the axial position detection coil A and the radial position detection coils R1, R2, The next output signal Vz is obtained from R3.

Vz = RI ₁ + jωLI ₁ + RI ₂
R: DC resistance value of the detection coil I ₁ : Effective value of the sine wave current ω: Angular frequency of the sine wave current L: Inductance of the detection coil I ₂ : DC current value The output signal Vz is converted to the high frequency circuit 63 and the synchronous detector. a sinusoidal signal V _L at 64, separated to the DC signal V _R at the low-frequency circuit 65.

V _L = RI ₁ + jωLI ₁
V _R = RI ₂
Axial position detection coils A and radial position detection coils R1, R2, R3 and by applying a high frequency signal DC superimposed on a sine wave such that I _{1 =} I ₂ relative to the DC from the sine wave signal V _L by excluding the signal V _R, eliminates the resistance component signal of the axial position detection coil a, the axial position detection coils a and radial position detection coils R1 is not affected by temperature, R2, R3 of the inductance component signal V Only ₀ is obtained.

V ₀ = jωLI ₁
The bearing wear detection can be accurately performed by the inductance component signal V ₀ of the axial position detection coil A and the radial position detection coils R1, R2, and R3 which are not affected by the temperature.

  FIG. 8 is a graph showing changes in the output of the axial wear signal and the radial wear signal during the operation of the canned motor pump 11, and changes in the liquid temperature of the pump handling liquid. The horizontal axis of the graph represents time, the left vertical axis represents the voltage of the wear signal output to the output circuit 89, and the right vertical axis represents the liquid temperature.

  By starting operation when the power of the canned motor 12 is turned on, the position of the rotor 25 is changed by the pumping liquid supplied by the rotation of the impeller 52 of the pump 13, and the axial wear signal and the radial wear signal are output. Changes. After the power is turned on, the liquid temperature in the can motor 12 gradually rises due to the heat generated by the can motor 12, and the axial position detection coil A and the radial position detection coils R1, R2,. R3 also rises in temperature and changes its resistance value. However, the temperature correction described above does not affect the output of the axial wear signal and the radial wear signal.

  When the flow rate of the pump handling liquid is changed and the flow rate of the pump handling liquid passing through the canned motor 12 increases, the temperature of the liquid gradually decreases and then gradually rises. Therefore, the output of the axial wear signal and the radial wear signal is not affected.

  By correcting the temperature in this way, the axial position and the radial position of the rotor 25 can be accurately detected by eliminating the influence of the temperature of the axial position detection coil A and the radial position detection coils R1, R2, and R3. . That is, a high-frequency signal superimposed on a sine wave is applied to the axial position detection coil A and radial position detection coils R1, R2, and R3, and the axial position detection coil A and radial position detection to which the high-frequency signal is applied. A sine wave signal and a DC resistance value are detected from the outputs of the coils R1, R2, and R3, respectively, and the axial position detection coil A and the radial position detection coils R1, R2 are obtained by removing the DC resistance value from the detected sine wave signal. , R3 inductance can be detected, and the axial position and radial position of the rotor 25 can be accurately detected by removing the influence of the temperature of the axial position detection coil A and the radial position detection coils R1, R2, R3. .

  Further, a high frequency signal is applied to the axial position detection coil A and the radial position detection coils R1, R2, and R3, and the axial position detection coil A and the radial position detection coils R1, R2, and R3 to which the high frequency signal is applied are applied. In order to detect the inductance and detect the axial position and the radial position of the rotor 25 from the inductances of the axial position detection coil A and the radial position detection coils R1, R2, and R3, the operation state or the operation stop of the canned motor 12 is detected. Regardless of the state, the axial position and radial position of the rotor 25 can be detected. Therefore, the axial position and radial position of the rotor 25 can be detected when the operation is stopped, and zero adjustment can be performed.

  Therefore, the zero point adjustment can be facilitated in the manufacturing process of the canned motor 12 and the productivity can be improved, and even when the bearing or rotor is replaced at the place where the canned motor 12 is used or maintenance is performed with tightening of the gasket. The zero point can be adjusted easily at the place.

  Further, as shown in FIG. 9, in addition to the radial position detection coils R1, R2, and R3 connected to the control circuit 61, the axial position detection coil A connected to the control circuit 61 is sequentially switched by the changeover switch 72. It can be configured to switch and connect. In this case, only one set of the high-frequency circuit 73, the synchronous detector 74, the low-frequency circuit 75, the amplifiers 78 and 79, etc. is required, and the circuit configuration can be simplified.

  The axial position detection coil A can also be wound along the outer periphery of the reinforcing ring 20 on the front side of the stator 17, and can be wound along the outer periphery of both the reinforcing rings 20 and 21 before and after the stator 17. When the reinforcing rings 20 and 21 are not used, they can be wound directly along the outer periphery of the stator can 19. Also, a pair of axial detection coils can be installed at both ends of the stator core 14 of the stator 17, and the axial position of the rotor 25 can be detected from the difference in inductance between these axial detection coils.

  In addition, the radial position detection coil is not limited to the case where it is installed on each of the three tooth portions positioned at equal intervals at an angular position of 120 ° among the plurality of tooth portions of the stator core 14 of the stator 17. Of the plurality of tooth portions of the stator core 14 of the child 17, it can be installed on each of the four tooth portions located at equal intervals at an angular position of 90 °.

  The zero adjustment device 87 may be provided outside the control circuit 61 or inside the control circuit 61.

  Moreover, in the said embodiment, although the example which applied the canned motor 12 to the canned motor pump 11 was shown, it can apply also to a canned motor agitator, a canned motor blower, etc., for example.

  Further, the bearing wear detection device is not limited to the canned motor 12, but can be applied to other motors using a sliding bearing such as a wet motor.

  Although not particularly illustrated, the application of the present invention is not limited to the bearing wear detection device that detects the bearing wear of the canned motor 12, but also to a detection device that detects inductance such as a rotor position sensor for magnetic bearing control. The same effect can be obtained.

1 is a circuit diagram of a bearing wear detection device showing a first embodiment of the present invention. It is sectional drawing of the canned motor pump to which a bearing wear detection apparatus same as the above is applied. It is a perspective view of the reinforcing ring and axial direction position detection coil of a bearing wear detection apparatus same as the above. It is a flowchart explaining the axial direction bearing wear detection operation | movement of a bearing wear detection apparatus same as the above. It is a graph which shows the change of the output of an axial direction wear signal when it is an output from a bearing wear detection apparatus same as the above, and a rotor moves to the back side by axial direction wear. It is a flowchart explaining the radial direction bearing wear detection operation | movement of a bearing wear detection apparatus same as the above. It is a graph which shows the change of the output of an axial direction wear signal and a radial direction wear signal when it is an output from a bearing wear detection apparatus same as the above and radial wear occurs. It is an output from a bearing wear detection apparatus same as the above, and is a graph showing changes in the axial wear signal, radial wear signal, and liquid temperature during operation of the canned motor pump. It is a circuit diagram of the bearing wear detection apparatus which shows the 2nd Embodiment of this invention.

Explanation of symbols

12 Canned motor as motor
17 Stator
25 rotor
62 High frequency power supply as high frequency signal applying means
66, 76 Sinusoidal signal detection means
67, 77 DC resistance value detection means
82 Inductance detection means
83 Axial position detection means
84 Radial position detection means A Axial position detection coil
R1, R2, R3 Radial position detection coil

Claims (3)

In the detection device for detecting the inductance of the detection coil,
High-frequency signal applying means for applying a high-frequency signal obtained by superimposing a direct current of the same value as the effective value of the sine wave on the sine wave to the detection coil;
Sine wave signal detection means for detecting a sine wave signal from the output of the detection coil to which the high frequency signal is applied;
DC resistance value detecting means for detecting a DC resistance value from the output of the detection coil to which the high frequency signal is applied;
Inductance detection means for detecting the inductance of the detection coil obtained by subtracting the DC resistance value detected by the DC resistance value detection means from the sine wave signal detected by the sine wave signal detection means. Detection device. A detection coil provided on the stator side of the motor;
High-frequency signal applying means for applying a high-frequency signal obtained by superimposing a direct current of the same value as the effective value of the sine wave on the sine wave to the detection coil;
Sine wave signal detection means for detecting a sine wave signal from the output of the detection coil to which the high frequency signal is applied;
DC resistance value detecting means for detecting a DC resistance value from the output of the detection coil to which the high frequency signal is applied;
Inductance detection means for detecting the inductance of the detection coil obtained by removing the DC resistance value detected by the DC resistance value detection means from the sine wave signal detected by the sine wave signal detection means,
An axial position detection means for detecting the axial position of the rotor of the motor from the inductance of the detection coil. A detection coil provided on the stator side of the motor;
High-frequency signal applying means for applying a high-frequency signal obtained by superimposing a direct current of the same value as the effective value of the sine wave on the sine wave to the detection coil;
Sine wave signal detection means for detecting a sine wave signal from the output of the detection coil to which the high frequency signal is applied;
DC resistance value detecting means for detecting a DC resistance value from the output of the detection coil to which the high frequency signal is applied;
Inductance detection means for detecting the inductance of the detection coil obtained by removing the DC resistance value detected by the DC resistance value detection means from the sine wave signal detected by the sine wave signal detection means,
A motor bearing wear detecting device comprising: a radial position detecting means for detecting a radial position of a rotor of the motor from an inductance of the detection coil.

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