JP5509970B2 - Vacuum pump - Google Patents

Description

  The present invention relates to a vacuum pump such as a turbo molecular pump.

  A DC brushless motor is used as a vacuum pump motor, and the rotation of the motor is detected by detecting the rotor rotation with a gap sensor (see, for example, Patent Document 1).

  The rotor is provided with a disk in which grooves are formed so as to face the gap sensor, a gap change accompanying the rotation of the disk is detected by the gap sensor, and a high-low signal is generated from the gap change. An excitation pattern of the stator coil is generated based on the generated high-low signal, and the motor is rotationally controlled.

Japanese Patent No. 3740083

  However, the accuracy of the gap sensor and the distance between the gap sensor and the sensor target vary depending on the pump machine base. For this reason, when generating a high-low signal, the high-low judgment cannot be performed correctly, the initial operation of the pump cannot be performed normally, or the rotor levitation position changes due to disturbance during operation, and the high-low judgment is correct. There was a risk of being unable to do so.

According to a first aspect of the present invention, there is provided a vacuum pump comprising: a rotor having a rotary-side exhaust function portion; a magnetic bearing for magnetically floating the rotor; and a magnetic bearing for controlling a floating position of the rotor by controlling an exciting current of the magnetic bearing. A control means, a motor for rotationally driving the rotor with respect to the fixed-side exhaust function unit, a sensor target provided integrally with the rotor and having a concavo-convex step formed on the target surface, and opposed to the target surface, the target surface Compares the voltage level of the sensor signal with the low level threshold and the high level threshold, and generates a low level signal and a high level signal corresponding to the uneven step. Signal generating means for controlling the motor and driving the motor to stop the rotor in order at a plurality of rotational angle positions when the power is turned on In at least one of the plurality of angular positions, the voltage level of the sensor signal is equal to or lower than a first determination threshold based on the low level threshold, and the voltage level of the sensor signal is at least one of the other angular positions. And a determination unit that determines that the sensor signal is normal when it is equal to or higher than the second determination threshold based on the high-level threshold, and that otherwise determines abnormal. .
According to a second aspect of the present invention, in the vacuum pump according to the first aspect, the magnetic bearing control means includes a first suction state in which the sensor target approaches the inductance type sensor at each of a plurality of angular positions, and the sensor target is The magnetic bearing is controlled so as to individually generate a second attraction state that moves away from the inductance type sensor, and the determination means includes the first attraction state and the second attraction in at least one of a plurality of angular positions. The voltage levels in the state are both equal to or lower than the first determination threshold value, and the voltage levels in the first suction state and the second suction state are both equal to or higher than the second determination threshold value in at least one of the other angular positions. In this case, the sensor signal is determined to be normal, and otherwise, it is determined to be abnormal.
The invention according to claim 3, in the vacuum pump according to claim 1 or 2, the motor is a three-phase motor, the motor control means, characterized by stopping the rotor at every rotation angle 120 deg.
According to a fourth aspect of the present invention, in the vacuum pump according to any one of the first to third aspects, the magnetic bearing is provided with a mechanical bearing that supports the rotor when the magnetic bearing is not in operation. The magnetic bearing is controlled so that the rotor comes into contact with the mechanical bearing during drive control by the motor control means.
The invention of claim 5 is the vacuum pump according to any one of claims 1 to 3, comprising a magnetic bearing that supports the rotor in a non-contact manner, and a mechanical bearing that supports the rotor when the magnetic bearing is not in operation. The magnetic bearing control means is characterized in that the magnetic bearing is deactivated and the rotor is supported by the mechanical bearing during drive control by the motor control means when power is turned on.
According to a sixth aspect of the present invention, in the vacuum pump according to any one of the first to fifth aspects, on the basis of the voltage levels of the sensor signals at a plurality of angular positions when determined to be abnormal by the determination means, Correction value setting means for setting a voltage correction value at which the sensor signal is determined to be normal by the determination means; and a correction means for correcting the high level threshold value and the low level threshold value or the voltage level of the sensor signal with the voltage correction value. It is characterized by having.
According to a seventh aspect of the present invention, there is provided a pump body having a rotor formed with a rotation-side exhaust function unit, a magnetic bearing for magnetically floating the rotor, and a motor for rotating the rotor with respect to the fixed-side exhaust function unit, and a pump body In a vacuum pump composed of a power supply device that controls driving, a pump body is provided integrally with a rotor, a sensor target having an uneven step formed on a target surface, and opposed to the target surface, and a gap between the target surface and the target surface. The power supply device compares the voltage level of the sensor signal with the low level threshold and the high level threshold, and compares the low level signal and the high level corresponding to the uneven step. A signal generation means for generating a level signal, and when the power is turned on, the motor is driven and controlled so that the rotor is moved to a plurality of rotational angle positions. And motor control means for stopping, measuring means for measuring the voltage level of the sensor signal at a plurality of angular positions, at least one of the plurality of angular positions, the first determination voltage level of the sensor signal based on the low level threshold Correction value setting means for setting a voltage correction value so that the voltage level of the sensor signal is equal to or higher than a second determination threshold based on the high level threshold at at least one of the other angular positions. It is characterized by providing.
The invention according to claim 8 is the vacuum pump according to claim 7, wherein the correction value setting means includes an average value of the low level threshold value and the high level threshold value and a minimum value and a maximum value of the plurality of measured voltage levels. An average value is obtained, and the difference value is set as a voltage correction value.
According to a ninth aspect of the present invention, in the vacuum pump according to the eighth aspect , the pump body includes pump-side identification information storage means in which pump identification information is stored, and the power supply device includes the pump identification information of the connected pump body. Recognizing means for recognizing, power supply side identification information storing means for storing the pump identification information recognized by the recognizing means, correction value storing means for storing the voltage correction value set by the correction value setting means, The identification information determination means for determining whether or not the pump identification information recognized by the recognition means and the pump identification information stored in the power supply side identification information storage means coincide with each other at the time of input. If it is determined that the correction means is correct, the correction means causes the correction means to correct the voltage correction value stored in the correction value storage means. The correction control means for correcting the correction means with the voltage correction value set by the positive value setting means and the pump identification information recognized by the recognition means when the identification information determination means does not match the power supply side An identification information rewriting means for rewriting the pump identification information stored in the identification information storage means is provided.
According to a tenth aspect of the present invention, in the vacuum pump according to the eighth aspect , the pump body includes reference value storage means in which the reference value of the voltage correction value is stored, and the power supply device is set by the correction value setting means. An alarm means for generating an alarm when the difference between the voltage correction value and the reference value is greater than or equal to a predetermined value is provided.

  According to the present invention, it is possible to prevent the generation of the high level signal and the low level signal from becoming unstable during the pump operation.

It is a figure which shows schematic structure of a turbo-molecular pump. It is a figure explaining the process in the rotation sensor circuit 43. FIG. It is a figure explaining the signal waveform in the process of the rotation sensor circuit 43, (a) shows the waveform of a modulated wave, (b) shows the waveform after a detection, (c) shows the waveform of a rotation pulse, respectively. It is a figure which shows the relationship between a rotation sensor signal and a determination threshold value. It is a flowchart which shows the procedure of check operation | movement. Sensor voltage measurements _V U, a diagram showing a measurement example of _{V V} and _{V W,} showing a case (a) if it is determined that the OK, (b), (c ) is to be determined as NG. It is a flowchart which shows an example for determining the time to a stationary state. It is a flowchart explaining control of the check operation | movement in 2nd Embodiment. It is a figure which shows the sensor voltage measured value in 2nd Embodiment, (a), (b) shows the case where it determines with OK, (c) shows the case where it determines with NG. It is a flowchart explaining control of the check operation | movement in 3rd Embodiment. It is a figure explaining the correction method in the correction process of step S300, (a) shows the voltage measurement value at the time of abnormality determination, (b) shows a 1st example, (c) shows a 2nd example. . It is a flowchart which shows the specific control example of the correction process of step S300, (a) shows a 1st example, (b) shows a 2nd example. It is a flowchart which shows the 1st modification of 3rd Embodiment. It is a flowchart which shows the 2nd modification of 3rd Embodiment. It is a flowchart which shows the 3rd modification of 3rd Embodiment. The perspective view of the sensor target 54. FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
-First embodiment-
FIG. 1 is a diagram showing a schematic configuration of a turbo molecular pump. The turbo molecular pump includes a pump body 1 and a power supply device 2. The pump body 1 is shown in cross section, and the power supply device 2 is a block diagram showing the main part.

  The turbo molecular pump shown in FIG. 1 is a magnetic bearing type turbo molecular pump, and the rotor 30 is supported in a non-contact manner by a radial magnetic bearing 37 and an axial magnetic bearing 38. The flying position of the rotor 30 is detected by a radial displacement sensor 27 and an axial displacement sensor 28. The rotor 30 magnetically levitated by the magnetic bearings is driven to rotate at high speed by the motor 36. As the motor 36, a three-phase motor (for example, a brushless DC motor) is used.

  The rotation of the rotor 30 is detected by a rotation sensor 33 constituted by an inductance type gap sensor. A sensor target 34 is provided at the lower end of the rotor 30 that is rotationally driven by the motor 36. The sensor target 34 rotates integrally with the rotor 30. The axial displacement sensor 28 and the rotation sensor 33 described above are arranged at positions facing the lower surface of the center target 34. 26 and 29 are emergency mechanical bearings, and the rotor 30 is supported by these mechanical bearings 26 and 29 when the magnetic bearing is not operating.

  The rotor 30 is formed with a plurality of stages of rotating blades 32 and a cylindrical screw rotor 31 that constitute the rotation-side exhaust function unit. On the other hand, the fixed side is provided with a fixed blade 32 and a screw stator 24 which are fixed side exhaust function units. The plurality of stages of fixed blades 22 are alternately arranged with the rotary blades 32 in the axial direction. The screw stator 24 is provided on the outer peripheral side of the screw rotor 31 with a predetermined gap. It should be noted that the present invention can be applied to an all-blade type turbo molecular pump without the screw rotor 31 and the screw stator 24, a drag pump without a rotating blade, and the like.

  Each fixed wing 22 is placed on the base 20 via the spacer ring 23. When the fixing flange 21c of the pump casing 21 is fixed to the base 20 with a bolt, the stacked spacer ring 23 is sandwiched between the base 20 and the pump casing 21, and the fixed blade 22 is positioned. The base 20 is provided with an exhaust port 25, and a back pump is connected to the exhaust port 25. When the rotor 30 is magnetically levitated and driven at high speed by the motor 36, the gas molecules on the intake port 21a side are exhausted to the exhaust port 25 side.

  The power supply device 2 is a device that drives and controls the pump body 1 and includes a CPU, a ROM, a RAM, and other peripheral circuits. The power supply device 2 includes a main control unit 40, a motor control unit 41, a magnetic bearing control unit 42, and a rotation sensor circuit 43. The motor control unit 41 controls driving of the motor 36. The magnetic bearing control unit 42 controls the excitation currents of the magnetic bearings 37 and 38 based on the output signals of the radial displacement sensor 27 and the axial displacement sensor 28, and magnetically floats the rotor 30 to a predetermined position. The rotation sensor circuit 43 acquires rotation information of the rotor 30 based on the output signal from the rotation sensor 33. This rotation information is used for rotation control of the motor 36, for example.

  FIG. 2 is a diagram for explaining processing in the rotation sensor circuit 43. A motor rotor 360 is attached to the rotor 30. By energizing the U-phase coil, the V-phase coil, and the W-phase coil arranged at 120 deg intervals on the motor stator side, the motor rotor 360 and the rotor 30 rotate integrally.

  As described above, the sensor target 34 is fixed to the lower end of the rotor 30, and the rotation sensor 33 is provided at a position facing the lower surface of the sensor target 34. The lower surface of the sensor target 34 is used as the target surface of the rotation sensor 33 and the axial displacement sensor 28 shown in FIG. The central target surface 34 </ b> C is used as the target surface of the axial displacement sensor 28. On the other hand, the stepped region including the convex surface 34H and the concave surface 34L in the peripheral portion is used as a target surface of the rotation sensor 33. The convex surface 34H and the concave surface 34L divide the target surface by 180 degrees in rotation angle.

  As shown in FIG. 2, the rotation sensor 33 includes a core having a high magnetic permeability such as a silicon steel plate or ferrite and a coil wound around the core. A high frequency voltage having a constant frequency and a constant amplitude is applied to the coil of the rotation sensor 33 as a carrier wave. The lines of magnetic force emitted from the core of the rotation sensor 33 return to the core through the sensor target 34 disposed oppositely.

  Since the target surface is composed of the convex surface 34H and the concave surface 34L, when the rotor 30 rotates, the gap between the target surface and the rotation sensor 33 changes. As a result, the carrier wave is amplitude-modulated by the inductance change, and a signal as shown in FIG. When the rotation sensor 33 is opposed to the convex surface 34H, a signal as indicated by a symbol A in FIG. On the other hand, when the rotation sensor 33 faces the concave surface 34L and the gap increases, the amplitude of the signal waveform decreases as indicated by the symbol B in FIG.

When the amplitude-modulated carrier wave of FIG. 3A is detected and rectified by the detection circuit 431 and the smoothing circuit 432, a signal as shown in FIG. 3B is obtained. The high-low determination unit 433 compares this signal with the high-low determination threshold value V _{H / L} to output a rotation pulse signal composed of a high level H and a low level L as shown in FIG. . Here, the rotation pulse signal is generated with one High-Low determination threshold value V _{H / L} , but in general, two determination values of a high level determination value V _H and a low level determination value V _L are obtained. To generate a rotation pulse signal.

By the way, since the accuracy of the rotation sensor 33 and the distance to the sensor target 34 vary for each pump unit, the sensor signal is shifted in the vertical direction with respect to the high-low determination threshold V _{H / L} as shown in FIG. May end up. In the rotation sensor signal S1 of the pump P1, the high level of the sensor signal is larger than the determination threshold V _{H / L} , and the low level is smaller than the determination threshold V _{H / L.} it can.

On the other hand, in the case of the pump P2, the signal level of the rotation sensor signal S2 is increased as a whole, and both the high level and the low level of the rotation sensor signal S2 are larger than the determination threshold V _{H / L.} Therefore, the high-low determination is impossible. For this reason, normal initial movement from a stationary state cannot be performed. Further, as in the rotation sensor signal S3, “high level> V _{H / L} ” is satisfied, but when the high level value is close to the determination threshold value V _{H / L} , vibration is generated. When the flying position changes slightly due to the above, etc., there is a possibility that the High-Low judgment may not be possible, and a malfunction may occur during rotation.

  Therefore, in the present embodiment, the power supply apparatus 2 has a function of automatically checking the voltage level of the High-Low signal (rotation sensor signal) when the power is turned on. FIG. 5 is a flowchart showing the procedure of the check operation executed by the main control unit 40 (see FIG. 1) of the power supply device 2. The process shown in FIG. 5 starts when the power supply device 2 is turned on.

  In step S10, a command is issued to the magnetic bearing control unit 42 so that the rotor 30 is lifted to a predetermined floating position. In step S20, a current is passed through only one phase of the U, V, W phase coils 361U to 361W shown in FIG. A series of processing from step S20 to step S40 is performed for each of the U, V, and W phases. Here, description will be made assuming that the processing is performed in the order of the U phase, the V phase, and the W phase.

  First, in step S20, the U-phase coil 361U is energized so that the rotor 30 is positioned at the rotor position corresponding to the U-phase energization. In step S30, it is determined whether or not the rotation of the rotor 30 has been settled and the stationary state has been reached. For this determination, for example, whether or not the rotation pulse of the rotation sensor 33 is interrupted can be used. Alternatively, it may be determined that a stationary state has elapsed after a predetermined time has passed after energization. Alternatively, an average stationary time may be obtained in advance using an actual machine, and the stationary time may be used as the predetermined time.

If it is determined in step S30 that the vehicle is stationary, the process proceeds to step S40 to measure the sensor voltage (voltage level of the rotation sensor signal). That is, the voltage level of the signal output from the smoothing circuit 432 of the sensor circuit 43 is acquired. The measurement result is stored as V _{U in} a memory (not shown) of the main control unit 40. In step S50, it is determined whether or not the processing from step S20 to step S40 has been completed for each of the U, V, and W phases. When the U-phase process is completed, it is determined in step S50 that the process has not been completed, and the process returns to step S20.

In this manner, the processes from step S20 to step S40 are executed for each of the U, V, and W phases, and sensor voltage measurement values V _U , V _V, and V _W are acquired. As described above, since the U-phase coil, the V-phase coil, and the W-phase coil are arranged at intervals of 120 deg, the voltage level for each 120 deg of the rotation sensor signal becomes the sensor voltage measurement values V _U , V when energized for each phase. It is obtained as _V and _{V W.}

In step S60, it is determined whether or not the sensor voltage measurement values V _{U to} V _W satisfy a predetermined determination condition. Here, the predetermined determination condition is a condition for determining whether or not the rotation sensor signal is normal. “At least one of the three measurement values V _{U to} V _W is equal to or less than the determination reference value V _L. and if "at least one criterion value V _H or determines to be normal. Determination reference value _V L, _{V H} is stored in advance in the memory of the main control unit 40, the determination reference value _V L, _{V H,} the threshold _V L for High-Low determination shown in FIG. 3 (b), It is set based on _VH . Here, the threshold value V _L for judging _High-Low, V _H to the determination reference value V _L, it is used as a V _H, for example, shifted threshold V _L for judging _High-Low, the V _H in the vertical A value (a value having a margin above and below) may be used as the determination reference value.

6A to 6C show measurement examples of sensor voltage measurement values V _U , V _V and V _W , where the vertical axis is the voltage value and the horizontal axis is the coil that is energized. Showing the phase. FIG. 6A shows an example of measured values when it is determined that the condition of step S60 is satisfied and OK. The sensor voltage measurement values V _U and V _V measured during the U-phase energization and the V-phase energization are equal to or higher than the determination reference value V _H , and the sensor voltage measurement value V _W measured during the W-phase energization is equal to or less than the determination reference value _VL Therefore, it is determined as OK.

In the example shown in FIG. 6, the rotation sensor 33 faces the convex surface 34H of the sensor target 34 at the time of U-phase energization and V-phase energization, and therefore usually has substantially the same sensor level. However, when the rotation sensor 33 is located at the boundary surface between the convex surface 34H and the concave surface 34L at the time of measurement, for example, the voltage level VU at the time of U-phase energization becomes V _L <V _U <V _H Also, the voltage levels at the time of V-phase energization and at the time of W-phase energization are V _V > V _H and V _W <V _L , and a High level signal and a Low level signal are obtained.

On the other hand, when this condition is not satisfied, for example, as shown in FIG. 6B, the two measurement values V _U and V _V are between the determination reference value V _L and the determination reference value V _H , or FIG. When the three measurement values V _U , V _V , and V _W are between the determination reference value V _L and the determination reference value V _H as in c), it is determined that the rotation sensor signal is abnormal. .

  If it is determined in step S60 that there is an abnormality (NO), the process proceeds to step S70 to notify the abnormality. For example, abnormal display is performed on a display device (for example, a liquid crystal display device) provided in the power supply device 2. Alternatively, an alarm sound may be emitted. On the other hand, if it is determined in step S60 that the condition is satisfied, the series of check processing ends. When the check process of FIG. 5 is completed, the power supply device 2 magnetically floats the rotor 30 to a predetermined position.

  In the control example shown in FIG. 6, since the rotor 30 is magnetically levitated and energized in one phase, it takes time for the rotor 30 to be stationary. In the control example shown in FIG. 7, the energy loss due to the mechanical bearings 26 and 29 is used to shorten the time until the stationary state is reached.

In step S20 of the flowchart shown in FIG. 7, the one-phase coil is energized while the magnetic levitation of the rotor 30 is stopped. Since the rotor 30 rotates while being supported by the mechanical bearings 26 and 29, the rotational energy is consumed as frictional energy, and the stationary state becomes shorter in a shorter time than in the case of the control of FIG. If it is determined in step S30 that it is stationary, the process proceeds to step S110, and the rotor 30 is magnetically levitated to a predetermined position. If the voltage level of the rotation sensor signal is measured in step S40, the magnetic levitation of the rotor 30 is stopped in step S120. By performing a series of processes from step S20 to step S120 for each of the U, V, and W phases, sensor voltage measurement values V _{U to} V _W are acquired.

  In the example shown in FIG. 7, the magnetic levitation of the rotor 30 is stopped and one-phase energization is performed. However, when the one-phase energization is performed while the rotor 30 is magnetically levitated as in the case of FIG. The bearing 37 may be controlled to decenter the floating position of the rotor 30 so that the rotor shaft contacts the mechanical bearings 26 and 29.

As described above, in the present embodiment, the sensor target 34 provided integrally with the rotor 30 and having the uneven surface formed on the target surface is disposed opposite to the target surfaces 34L and 34H, and the target surfaces 34L and 34H An inductance type rotation sensor 33 that outputs a sensor signal corresponding to a gap change, and compares the voltage level of the sensor signal with a low level threshold V _L (lower threshold) and a high level threshold V _H (upper threshold), And a rotation sensor circuit 43 as signal generation means for generating a low level signal and a high level signal corresponding to the uneven step. When the power is turned on, the motor control unit 41 drives and controls the motor 36 to stop the rotor 30 in order at a plurality of rotation angle positions. In at least one of the plurality of angular positions, the voltage level (V _{U to} V _W ) of the sensor signal is equal to or lower than the determination threshold value V _L , and the voltage level (V _{U to} V _W is at least one of the other angular positions. ) Is greater than or equal to the determination threshold V _H , the sensor signal is determined to be normal, and otherwise it is determined to be abnormal.

  By automatically making such a determination (checking operation) when the power is turned on, it is possible to confirm that the performance and wiring of the rotation sensor 33 are normal before rotating the pump. Therefore, it is possible to prevent a situation in which an accurate rotation pulse cannot be obtained due to disturbance or the like.

-Second Embodiment-
FIG. 8 is a flowchart for explaining the control of the check operation in the second embodiment. In the flowchart of FIG. 8, Steps S110 and S40 in the flowchart shown in FIG. 7 are replaced with the processes of Steps S210 to S240. In step S20, the one-phase coil is energized with the magnetic levitation of the rotor 30 stopped. As in the case of the control in FIG. 7, the rotor 30 becomes stationary in a short time due to the friction of the mechanical bearings 26 and 29.

  If it is determined in step S30 that the motor is stationary, the process proceeds to step S210, and the magnetic bearing is controlled so as to attract the rotor 30 upward (to the pump intake port side). With respect to the floating position of the rotor 30 in the axial direction, the vertical movement of the rotor 30 is restricted by a lower mechanical bearing 29 in which an angular contact type bearing is used. Therefore, the rotor 30 is magnetically levitated to the upper limit position in the axial direction by the process of step S210, and the gap between the rotation sensor 33 and the center target 34 becomes larger than that during normal levitation. As a result, the voltage level of the rotation sensor signal measured in step S220 is smaller than that during normal ascent.

  In the subsequent step S230, contrary to the case of step S210, the magnetic bearing is controlled so as to attract the rotor 30 downward (pump base side). As a result, the rotor 30 is magnetically levitated to the lower limit position in the axial direction, and the gap between the rotation sensor 33 and the center target 34 becomes smaller than that during normal levitation. Therefore, the voltage level of the rotation sensor signal measured in step S240 is higher than that during normal ascent.

  If the measurement process of step S240 is completed, the process proceeds to step S120, and the magnetic levitation of the rotor 30 is stopped. In step S50, it is determined whether or not the U-phase, V-phase, and W-phase measurement processes have been completed. As in the case of the control of FIG. 7, when the processing from step S20 to step S120 is repeated in the order of the U phase, the V phase, and the W phase, the sensors as shown in FIGS. A voltage measurement value is acquired.

  In FIG. 9, the three data with the reference C1 are the sensor voltage measurement values at the time of upper suction, and the three data with the reference C2 are the sensor voltage measurement values at the time of lower suction. As described above, since the gap between the sensor and the target is smaller at the time of lower suction than at the time of upper suction, the voltage value is larger at the time of lower suction.

In step S60, for each pair of the voltage value at the time of upper suction and the voltage value at the time of lower suction of each phase, a comparison is made with the determination reference values V _L and V _H for each pair. Then, there is at least one phase in which both the up-and-down suction measurement values C1 and C2 are smaller than the determination reference value V _L , and both the up-and-down suction measurement values C1 and C2 are higher than the determination reference value V _H. If there is at least one phase that becomes large, it is determined in step S60 that it is normal (OK).

In the example shown in FIG. 9 (a), the upper and lower suction during measurement value C1 at time and V-phase current supply U-phase current supply, C2 is greater than the determination reference value V _H, W-phase current supply when the upper and lower suction time of measurement values C1, C2 Is smaller than the determination reference value _VL , it is determined that the rotation sensor signal is normal (OK). It should be noted that the case of FIG. 9B is also determined to be OK. On the other hand, in the example shown in FIG. 9C, since the upper suction measurement value C1 during the U-phase energization and the V-phase energization is between the determination reference value V _L and the determination reference value V _H , the rotation sensor signal Is determined to be abnormal (NG).

  As described above, in the second embodiment, the check operation is performed using the measurement value in the state where the rotor 30 is attracted up and down by the magnetic bearing. Therefore, when it is determined that the check operation is OK, a normal rotation sensor signal can be reliably acquired even if the floating position of the rotor 30 rises and falls due to disturbance or the like during pump operation. The control used is not affected. Further, in the case of this check operation, it is also determined as abnormal when the mechanical bearing 29 is significantly worn and the range in which the rotor 30 can move up and down is widened. Therefore, it is possible to prevent the mechanical bearing 29 from being used in an abnormal state.

-Third embodiment-
FIG. 10 is a flowchart for explaining the control of the check operation in the third embodiment. In the flowchart of FIG. 10, the correction process of step S300 is performed instead of the process of step S70 of the flowchart shown in FIG. FIG. 12 shows specific processing of the correction processing in step S300. In addition, although FIG. 10 demonstrates as an example the case where up-and-down suction is performed, even when not performing up-and-down suction as shown in FIGS.

  The correction process will be described by taking as an example the case where data as shown in FIG. 11A is obtained by the processes from step S20 to step S50. In the measurement data example shown in FIG. 11A, the rotation sensor 33 faces the convex surface 34H of the target 34 during the U-phase energization and the V-phase energization, and opposes the concave surface 34L of the target 34 during the W-phase energization. ing.

In the example shown in FIG. 11A, each voltage value is shown as a relative value with the determination reference value V _L0 being 100. That is, the determination reference value V _L0 = 100, the determination reference value V _H0 = 200, the U-phase upper suction measurement value V _UU = 195, the lower suction measurement value V _UL = 250, and the V-phase upper suction measurement value V _VU. = 195, lower suction measurement value V _VL = 250, W phase upper suction measurement value V _WU = 10, lower suction measurement value V _WL = 45. In this case, the determination condition in step S60 is not satisfied, and the process proceeds to the correction process in step S300.

V _L0 and V _H0 are initial values of determination reference values, and are stored and held in the memory of the main control unit 40 of the power supply device 2 at the time of pump shipment inspection.

FIG. 12A shows a first example of correction processing. In step S310, the correction value ΔV is calculated by the following equation (1), and the calculation result is stored in the memory of the main control unit 40. This correction value ΔV represents the amount of deviation of the median value of the measurement values V _UU and V _WL inside the measurement value range from the median value of the determination reference values V _L0 and V _H0 . Here, as the measurement values (V _UU and V _{WL in} this example) used to calculate the correction value ΔV, the maximum value at the time of upper suction and the minimum value at the time of lower suction are usually selected from the three phases.
ΔV = (V _H0 + V _L0 ) / 2− (V _UU + V _WL ) / 2
= 30 (1)

In step S320, the determination reference values V _L0 and V _H0 are corrected to V _L = V _L0 + ΔV and V _H = V _H0 + ΔV using the correction value ΔV calculated in step S310, and these V _L , V _H is stored in the memory of the main control unit 40 as a corrected determination reference value. This correction is a process of matching the median value of the determination reference value with the median values of the measured values V _UU and V _WL . In the example shown in FIG. 11B, the correction value ΔV is ΔV = 30, and the corrected determination reference values V _L (= 70) and V _H (= 170) are the determination reference values V _L0 (= 100). ), V _H0 (= 200) are respectively shifted downward by a correction value ΔV (= 30).

In step S330, as in the case of the determination reference values V _L0 and V _H0 , the upper and lower threshold values (V _L and V _{H in} FIG. 3B) are corrected by the correction value ΔV, and the corrected upper and lower thresholds are corrected. A threshold value is set in the sensor circuit 43. Here, since the determination reference values V _L0 and V _H0 are set to the same value as the upper and lower threshold values for the High-Low determination, the values 70 and 170 are set as the upper and lower threshold values for the High-Low determination. When the process of step S330 ends, the process returns to FIG. 10, and the series of processes ends. Thereafter, the rotation pulse signal shown in FIG. 3C is generated using the corrected upper and lower threshold values. Further, when activated again, a series of processing of FIG. 10 is performed using the corrected determination reference values V _L and V _H stored in the main control unit 40.

  The process shown in FIG. 10 is performed every time the power supply device 2 is activated. However, normally, it is rarely determined as NO in step S60 unless the pump body 1 is replaced or the rotation sensor 33 changes with time. Conversely, if the pump body 1 has been replaced or the rotation sensor 33 has changed over time, the process proceeds from step S60 to step S310, and the determination reference value and the upper and lower threshold values are automatically corrected. For this reason, when the pump body 1 is replaced, it is not necessary to manually adjust the determination reference value and the upper and lower threshold values, and an easy-to-use turbo molecular pump can be provided.

FIG. 11C and FIG. 12B are diagrams illustrating a second example of the correction process. In the first example described above, the upper and lower thresholds of the determination reference values V _L0 and V _H0 and the high-low determination are corrected with the correction value ΔV. In the second example, as shown in FIG. The voltage level was corrected.

If NO is determined in step S60, the process proceeds to step S300, and correction processing as shown in FIG. 12B is performed. In step S310, the correction value ΔV is calculated using equation (1). In step S350, the setting of the smoothing circuit 432 is changed so that the voltage level of the signal output from the smoothing circuit 432 in FIG. 2 is increased by ΔV. When ΔV is a negative value, the voltage level is lowered. After the setting change, upper suction measurement values V ′ _UU , V ′ _VU , V ′ _WU and lower suction measurement values V ′ _UL , V ′ _VL , V ′ _WL as shown in FIG. It will be.

  As described above, in the third embodiment, when the rotation sensor signal does not satisfy the determination condition, the high / low determination upper and lower thresholds and the rotation sensor are performed so that the correction process of step S300 is performed to satisfy the determination condition. The voltage level of the signal was corrected. As a result, even if the high-low determination cannot be correctly performed before the correction, the high-low determination can be reliably performed by the correction.

  In the control example shown in FIG. 10, correction processing as shown in FIGS. 12A and 12B is performed only when it is determined NO (not satisfying the determination condition) in step S <b> 60. If step S60 is omitted and if YES is determined in step S50, the correction process in step S300 may be performed regardless of whether the determination condition is satisfied.

  Even in this case, even if the high-low determination cannot be correctly performed before the correction, the correction can reliably perform the high-low determination. Further, when the up / down suction is not performed as shown in FIGS. 5 and 7 and the voltage level satisfies the determination condition of step S60, the correction processing as in the second example is performed. Thus, a voltage level with a margin with respect to the determination condition can be obtained.

  In the description of the third embodiment described above, the above-described check operation is performed each time the power supply device 2 is activated, and the correction process in step S300 is performed. Below, the modification of control which performs a correction process is demonstrated.

(First modification)
The first modification is a control example in the case where the power supply device 2 is configured to recognize each connected pump body 1. It is assumed that when the power supply device 2 is connected to the pump body 1, the power supply device 2 can acquire identification information of the pump body 1 such as a serial number. For example, a storage element in which a serial number is stored is provided in the pump body 1, and the power supply device 2 reads the serial number when the power is turned on.

  FIG. 13 is a flowchart illustrating a control example in the first modification. When the power is turned on, the serial number is read from the pump body 1 side in step S410. In step S420, the read serial number is compared with the serial number stored in the memory of the main control unit 40 of the power supply device 2 to determine whether or not they match. The memory of the main control unit 40 stores the serial number of the pump body 1 connected before the power is turned on. Therefore, when the pump main body 1 different from that before the power is turned on is determined as NO in Step S420.

  If it is determined in step S420 that the values match, the process proceeds to step S430, and correction processing is performed using the correction value ΔV stored in the power supply device 2. When the correction value ΔV is set for the pump body 1 connected before the power is turned on, the correction value ΔV is stored in the memory of the main control unit 40. If the serial numbers match in step S420, the connected pump body 1 is the same as the pump body 1 before the power is turned on, so that the correction value stored on the power supply device 2 side as in step S430. Correction processing is performed using ΔV.

  On the other hand, when the pump main body 1 is replaced, the serial numbers are different from each other. Therefore, NO is determined in the step S420, and the process proceeds to the step S440. In step S440, the check process and the correction process shown in FIG. 10 are performed, and the correction value ΔV stored in the main control unit 40 is rewritten with the newly calculated correction value ΔV. In step S450, the serial number stored in the memory of the main control unit 40 is replaced with the serial number read from the connected pump body 1 side.

  As described above, in the first modification, the check operation is performed only when the pump body 1 connected to the power supply device 2 is replaced. Therefore, when the pump is not replaced, the check operation is omitted and the startup process is shortened.

(Second modification)
A second modification will be described with reference to the flowchart of FIG. In the second modification, a control example based on the premise that the initial value ΔV ₀ of the correction value is stored in advance in the pump body 1 will be described. For example, at the time of pump shipment inspection or pump overhaul, the above check process is performed, and a correction value ΔV is obtained based on the result, and the correction value ΔV is set as an initial value ΔV ₀ in a storage element provided in the pump body. Remember.

In step S510, check processing from step S20 to step S50 in FIG. 8 is performed. In step S520, a correction value ΔV is calculated based on the measurement value obtained in the check process in step S510. In step S530, the above-described initial value ΔV ₀ is read from the pump body 1 side, and it is determined whether or not the difference between the calculated correction value ΔV and the initial value ΔV ₀ is within an allowable range.

For example, assuming that the initial value ΔV ₀ on the pump body side is 30, and the correction value ΔV derived after a lapse of a certain period is 10, the distance between the sensor and the target is the initial value corresponding to the correction value = 20. It is closer than the state. Possible causes of such changes include loosening of the target 34 fixed to the rotor shaft and wear of mechanical bearings. If the difference from the initial value ΔV ₀ exceeds the preset allowable range, NO is determined in step S530.

If it is determined in step S530 that the value is within the allowable range (YES), correction processing is performed using the calculated correction value ΔV in step S540. In this correction process, as shown in FIGS. 11B and 12A, a process of correcting the upper and lower thresholds for the High-Low determination with the correction value ΔV is employed. Note that the determination reference value is not corrected, and the initial values V _L0 and V _H0 are always used.

On the other hand, if it is determined in step S530 that the allowable range is exceeded, the process proceeds to step S550 to generate an alarm indicating an abnormality of the rotation sensor signal. As described above, by checking the change in the actual correction value ΔV with respect to the initial value ΔV ₀ when the power is turned on, the abnormality of the rotation sensor 33 can be detected at an early stage. If the initial value ΔV ₀ is not stored on the pump body 1 side, the calculated correction value ΔV is stored on the pump side as an initial value after the process of step S540. From the next check, the control shown in FIG. 14 is performed using the value.

As described above, in the second modification, the change over time of the correction value can be managed using the initial value ΔV ₀ stored in the pump body. Therefore, the abnormality of the rotation sensor signal can be checked by the change of the correction value ΔV ₀ .

(Third Modification)
A third modification will be described with reference to the flowchart of FIG. In the third modification, the calculated correction value ΔV is stored in the pump main body 1 and the power supply device 2. In this case, the initial value ΔV ₀ may or may not be stored in the pump as in the second modification. When the initial value ΔV ₀ is stored, when the correction value calculation is performed, the initial value ΔV ₀ in the pump body 1 is rewritten by the calculated correction value ΔV.

  In step S610, the correction value ΔV stored in the pump body 1 is read into the power supply device 2 side. In step S620, the difference between the read correction value and the correction value stored and held in the power supply device 2 is calculated, and it is determined whether or not the difference is within the reference. If the pump body 1 has not been replaced before the power is turned on, “difference = 0” is obtained, but if the pump body 1 is replaced, “difference ≠ 0” is generally obtained. Therefore, the reference value for the determination in step S620 may be set to a difference that can be determined for pump replacement (a difference in the machine base of the pump body 1).

  If it is determined in step S620 that it is within the reference, the process proceeds to step S630, and the correction value ΔV stored in the memory of the main control unit 40 in the power supply device 2 is rewritten with the correction value read from the pump body side. In step S640, correction processing is performed using the rewritten correction value ΔV.

  On the other hand, if it is determined in step S620 that the difference is not within the reference, the process proceeds to step S650, and the check process and the correction process shown in FIG. 10 are performed. If the difference exceeds the determination reference value, not only replacement of the pump main body but also various factors can be considered, and thus processing such as step S650 is performed. Thereafter, in step S660, the correction value in the pump main body 1 and the correction value in the power supply device 2 are rewritten with the calculated correction value.

  In the third modification, the calculated correction value is stored in the pump body 1 and checked when the difference between the correction value in the pump body 1 and the correction value in the power supply device 2 is within the reference when the power is turned on. Since the process is omitted, the startup process is shortened.

  In the above-described embodiment, the sensor target 34 having a step formed in the axial direction of the rotor shaft has been described as an example. However, a sensor target 54 as shown in FIG. 16 is provided in the rotor 30 and rotated in the radial direction. The sensor 33 may be arranged to detect the target surfaces 54H and 54L formed on the side surface of the sensor target 54. When the rotation sensor 33 is arranged in the axial direction as shown in FIG. 2, the rotor 30 is sucked up and down to obtain a voltage measurement value as shown in FIG. 11A. In the case of the configuration of FIG. In this case, the same voltage measurement value can be acquired by sucking the rotor 30 in the radial direction.

  In addition, the case where the motor 36 is a brushless DC motor has been described as an example. However, the present invention is not limited to this, and the present invention can be applied to other three-phase or multiphase motors.

  Each of the embodiments described above may be used alone or in combination. This is because the effects of the respective embodiments can be achieved independently or synergistically. In addition, the present invention is not limited to the above embodiment as long as the characteristics of the present invention are not impaired.

  DESCRIPTION OF SYMBOLS 1: Pump main body, 2: Power supply device, 22: Fixed blade, 24: Screw stator, 26, 29: Mechanical bearing, 30: Rotor, 31: Screw rotor, 32: Rotary blade, 33: Rotation sensor, 34, 54: Sensor target 36: motor, 37, 38: magnetic bearing, 40: main control unit, 41: motor control unit, 42: magnetic bearing control unit, 43: rotation sensor circuit, 34H: convex surface, 34L: concave surface, 361U: U-phase coil , 361V: V phase coil, 361W: W phase coil

Claims (10)

A rotor formed with a rotation-side exhaust function unit;
A magnetic bearing for magnetically levitating the rotor;
Magnetic bearing control means for controlling the floating position of the rotor by controlling the excitation current of the magnetic bearing;
A motor that rotationally drives the rotor with respect to the fixed-side exhaust function unit;
A sensor target provided integrally with the rotor and having a stepped surface on the target surface;
An inductance sensor that is disposed opposite to the target surface and outputs a sensor signal corresponding to a gap change with the target surface;
A signal generation means for comparing the voltage level of the sensor signal with a low level threshold and a high level threshold to generate a low level signal and a high level signal corresponding to the uneven step;
Motor control means for driving and controlling the motor to stop the rotor in order at a plurality of rotation angle positions when power is turned on;
At least one of the plurality of angular positions, the voltage level of the sensor signal is equal to or lower than a first determination threshold based on the low level threshold, and the voltage level of the sensor signal is at least one of the other angular positions. And a determination unit that determines that the sensor signal is normal when the value is equal to or greater than a second determination threshold value based on the high level threshold value, and that is otherwise abnormal. . The vacuum pump according to claim 1, wherein
The magnetic bearing control means has a first attraction state in which the sensor target approaches the inductance sensor and a second attraction state in which the sensor target moves away from the inductance sensor at each of the plurality of angular positions. Controlling the magnetic bearings to be generated individually,
In the determination means, at least one of the plurality of angular positions, the voltage levels in the first suction state and the second suction state are both less than or equal to the first determination threshold value, and other angular positions When the voltage level in both the first suction state and the second suction state is equal to or higher than the second determination threshold value, the sensor signal is determined to be normal, and A vacuum pump characterized by determining that it is abnormal in some cases. The vacuum pump according to claim 1 or 2,
The motor is a three-phase motor;
The said motor control means stops the said rotor for every rotation angle 120deg, The vacuum pump characterized by the above-mentioned. The vacuum pump according to any one of claims 1 to 3,
A mechanical bearing that supports the rotor when the magnetic bearing is not in operation;
The said magnetic bearing control means controls the said magnetic bearing so that the said rotor may contact with the said mechanical bearing at the time of the drive control by the said motor control means at the time of power activation. The vacuum pump according to any one of claims 1 to 3,
A magnetic bearing for supporting the rotor in a non-contact manner;
A mechanical bearing that supports the rotor when the magnetic bearing is not in operation;
The said magnetic bearing control means makes the said magnetic bearing a non-operation state at the time of the drive control by the said motor control means at the time of power activation, The vacuum pump characterized by the above-mentioned. The vacuum pump according to any one of claims 1 to 5,
A correction value for setting a voltage correction value for determining that the sensor signal is normal by the determination unit based on the voltage levels of the sensor signal at the plurality of angular positions when the determination unit determines that the abnormality is present. Setting means;
A vacuum pump comprising: correction means for correcting the high level threshold value and the low level threshold value or the voltage level of the sensor signal with the voltage correction value. A rotor formed with a rotation-side exhaust function part, a magnetic bearing that magnetically floats the rotor, a pump body having a motor that rotationally drives the rotor with respect to a fixed-side exhaust function part, and a power source that drives and controls the pump body In a vacuum pump composed of a device,
The pump body is
A sensor target provided integrally with the rotor and having a stepped surface on the target surface;
An inductance sensor that is disposed opposite to the target surface and outputs a sensor signal in accordance with a gap change with the target surface;
The power supply device
A signal generation means for comparing the voltage level of the sensor signal with a low level threshold and a high level threshold to generate a low level signal and a high level signal corresponding to the uneven step;
Motor control means for driving and controlling the motor to stop the rotor in order at a plurality of rotation angle positions when power is turned on;
Measuring means for measuring each voltage level of the sensor signal at the plurality of angular positions;
At least one of the plurality of angular positions, the voltage level of the sensor signal is equal to or lower than a first determination threshold based on the low level threshold, and the voltage level of the sensor signal is at least one of the other angular positions. Correction value setting means for setting a voltage correction value so that is equal to or higher than a second determination threshold value based on the high level threshold value;
A vacuum pump comprising: correction means for correcting the high level threshold value and the low level threshold value, or the voltage level of the sensor signal with the voltage correction value. The vacuum pump according to claim 7,
The correction value setting means obtains an average value of the low level threshold and the high level threshold and an average value of minimum and maximum values of the plurality of measured voltage levels, and uses the difference value as a voltage correction value. A vacuum pump characterized by setting. The vacuum pump according to claim 8 ,
The pump body includes pump-side identification information storage means in which pump identification information is stored,
The power supply device
Recognition means for recognizing the pump identification information of the connected pump body;
Power supply side identification information storage means for storing pump identification information recognized by the recognition means;
Correction value storage means for storing the voltage correction value set by the correction value setting means;
Identification information determination means for determining whether or not the pump identification information recognized by the recognition means coincides with the pump identification information stored in the power supply side identification information storage means when the power is turned on;
If it is determined by the identification information determination means that the values match, the correction means corrects the correction means with the voltage correction value stored in the correction value storage means, and it is determined that they do not match. A correction control means for correcting the correction means with the voltage correction value set by the correction value setting means,
An identification information rewriting unit that rewrites the pump identification information stored in the power source side identification information storage unit with the pump identification information recognized by the recognition unit when the identification information determination unit determines that they do not match, A vacuum pump comprising: The vacuum pump according to claim 8 ,
The pump body includes a reference value storage means in which a reference value of the voltage correction value is stored,
The vacuum pump according to claim 1, wherein the power supply device includes alarm means for generating an alarm when a difference between the voltage correction value set by the correction value setting means and the reference value is a predetermined value or more.

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