JP2015129521A - vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum pump capable of easily obtaining excellent sensitivity and measurement signal of a sensor without adjusting a mounting position of the sensor.SOLUTION: A vacuum pump includes: a rotating portion composed of a rotor having a rotary vane, a cylindrical portion, and a conductor, and a rotor shaft fixed to the rotor; a non-rotating portion provided with a sensor coil of which inductance changes in accompany with temperature change of the rotor; and a control device provided with an oscillator supplying a high frequency voltage to the sensor coil, and a sensor circuit outputting a temperature measurement signal on the basis of modulated voltage of which amplitude is modulated by inductance change of the sensor coil, and detecting the temperature of the rotating portion on the basis of the change by the temperature change of the rotating portion, of eddy current of the rotating portion causing the change of the inductance.

Description

  The present invention relates to a vacuum pump, and more particularly to a vacuum pump capable of easily obtaining a good measurement signal without adjusting a sensor mounting position.

With the recent development of electronics, the demand for semiconductors such as memories and integrated circuits is increasing rapidly.
These semiconductors are manufactured by doping impurities into a highly pure semiconductor substrate to impart electrical properties, forming a fine circuit pattern on the semiconductor substrate, and laminating them.

  These operations need to be performed in a high vacuum chamber in order to avoid the influence of dust in the air. A vacuum pump is generally used for evacuating the chamber, but a turbo molecular pump, which is one of the vacuum pumps, is often used because it has a small residual gas and is easy to maintain.

  Also, in the semiconductor manufacturing process, there are many processes in which various process gases are applied to the semiconductor substrate. The turbo molecular pump not only evacuates the chamber, but also exhausts these process gases from the chamber. Also used.

  Furthermore, turbo molecular pumps are also used in equipment such as electron microscopes to prevent the refraction of the electron beam due to the presence of dust, etc., so that the environment in the chamber of the electron microscope or the like is brought into a highly vacuum state. Yes.

  Such a turbo molecular pump includes a turbo molecular pump main body for sucking and exhausting gas from a chamber of a semiconductor manufacturing apparatus, an electron microscope, or the like, and a control device for controlling the turbo molecular pump main body.

Here, a longitudinal sectional view of the turbo molecular pump main body is shown in FIG.
In FIG. 6, the turbo molecular pump main body 100 has an intake port 101 formed at the upper end of a cylindrical outer cylinder 127. On the inner side of the outer cylinder 127, there is provided a rotating body 103 in which a plurality of rotating blades 102a, 102b, 102c,... As turbine blades for sucking and exhausting gas are formed radially and in multiple stages.

  A rotor shaft 113 is attached to the center of the rotating body 103. The rotor shaft 113 is levitated and supported by a so-called 5-axis control magnetic bearing, for example.

The upper radial electromagnet 104 forms a pair with an X axis and a Y axis in which four electromagnets are orthogonal to each other, and is disposed so as to sandwich the rotor shaft 113. The X axis and the Y axis are assumed to be on a plane perpendicular to the axis of the rotor shaft 113 when the rotor shaft 113 is at the control target position of the magnetic bearing. Further, in the vicinity of the four electromagnets of the upper radial electromagnet 104, an upper radial sensor 107 composed of four coils corresponding to each electromagnet and arranged opposite to each other with the rotating body 103 interposed therebetween is provided. . The upper radial direction sensor 107 is configured to detect the radial position of the rotating body 103 and send the signal to the control device.
The rotor shaft 113 is formed of a high permeability material (such as iron) and is attracted by the magnetic force of the upper radial electromagnet 104.

Further, the lower radial electromagnet 105 and the lower radial sensor 108 are arranged in the same manner as the upper radial electromagnet 104 and the upper radial sensor 107, and the lower radial sensor 108 has a lower diameter of the rotor shaft 113. It is configured to detect the directional position and send the signal to the control device.
And the upper and lower radial positions of the rotor shaft 113 are adjusted by the magnetic bearing feedback control means of the control device.

  Furthermore, axial electromagnets 106A and 106B are arranged with a disk-shaped metal disk 111 provided at the lower part of the rotor shaft 113 sandwiched vertically. The metal disk 111 is made of a high permeability material such as iron. An axial sensor 109 is provided to detect the axial position of the rotating body 103, and the axial position signal is sent to the control device.

  The axial electromagnet 106A attracts the metal disk 111 upward by magnetic force, and the axial electromagnet 106B attracts the metal disk 111 downward.

  As described above, in the control device, the magnetic force exerted on the metal disk 111 by the axial electromagnets 106A and 106B is appropriately adjusted by the magnetic bearing feedback control means, the rotor shaft 113 is magnetically levitated in the axial direction, and is not in contact with the space. Hold.

The motor 121 includes a plurality of permanent magnet magnetic poles arranged circumferentially so as to surround the rotor shaft 113 on the rotor side. These permanent magnets are applied with torque for rotating the rotor shaft 113 from an electromagnet on the stator side of the motor 121, and the rotating body 103 is driven to rotate.
The motor 121 is provided with a rotation speed sensor and a motor temperature sensor (not shown). Upon receiving detection signals from the rotation speed sensor and the motor temperature sensor, the rotation of the rotor shaft 113 is controlled by the control device. Yes.

  A plurality of fixed blades 123a, 123b, 123c,... Are arranged with a slight gap from the rotor blades 102a, 102b, 102c,. The rotor blades 102a, 102b, 102c,... Are each inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to transfer exhaust gas molecules downward by collision.

Similarly, the fixed blades 123 are also formed to be inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and are arranged alternately with the stages of the rotary blades 102 toward the inside of the outer cylinder 127. ing.
And the one end of the fixed wing | blade 123 is supported in the state inserted and inserted between the fixed wing | blade spacer 125a, 125b, 125c, ... stacked in several steps.

The fixed blade spacer 125 is a ring-shaped member and is made of a metal such as a metal such as aluminum, iron, stainless steel, or copper, or an alloy containing these metals as components.
An outer cylinder 127 is fixed to the outer periphery of the fixed blade spacer 125 with a slight gap. A base portion 129 is disposed at the bottom of the outer cylinder 127, and a threaded spacer 131 is disposed between the lower portion of the fixed blade spacer 125 and the base portion 129.

  An exhaust port 133 is formed below the threaded spacer 131 in the base portion 129. A dry pump passage (not shown) is connected to the exhaust port 133, and the exhaust port 133 is connected to a dry pump (not shown) via the dry pump passage.

The threaded spacer 131 is a cylindrical member made of metal such as aluminum, copper, stainless steel, iron, or an alloy containing these metals as a component, and a plurality of spiral thread grooves 131a are formed on the inner peripheral surface thereof. It is marked.
The direction of the spiral of the thread groove 131 a is a direction in which molecules of the exhaust gas move toward the exhaust port 133 when the molecules of the exhaust gas move in the rotation direction of the rotating body 103.

  A cylindrical portion 102d is suspended from the lowermost portion of the rotating body 103 following the rotor blades 102a, 102b, 102c,. The outer peripheral surface of the cylindrical portion 102d protrudes toward the inner peripheral surface of the threaded spacer 131, and is close to the inner peripheral surface of the threaded spacer 131 with a predetermined gap.

  The base portion 129 is a disk-like member that forms the base portion of the turbo molecular pump main body 100, and is generally made of a metal such as iron, aluminum, or stainless steel. Since the base portion 129 physically holds the turbo molecular pump main body 100 and also has a function of a heat conduction path, a metal having rigidity such as iron, aluminum, and copper and high heat conductivity is used. Is desirable.

  The base portion 129 is provided with a connector 160, and a cable for electrically connecting the turbo molecular pump main body 100 and the control device is connected to the connector 160.

  In such a configuration, when the rotating blade 102 is driven and rotated by the motor 121 together with the rotor shaft 113, exhaust gas is sucked from a chamber (not shown) through the intake port 101 by the action of the rotating blade 102 and the fixed blade 123.

  Exhaust gas sucked from the inlet 101 passes between the rotary blade 102 and the fixed blade 123 and is transferred to the base portion 129. The exhaust gas transferred to the base portion 129 is sent to the exhaust port 133 while being guided by the thread groove 131a of the threaded spacer 131.

  Here, the turbo-molecular pump main body 100 requires control based on specification of a model and unique parameters (for example, various characteristics corresponding to the model) individually adjusted. In order to store the control parameters, the turbo molecular pump main body 100 includes an electronic circuit unit 141 therein. The electronic circuit unit 141 includes a semiconductor memory such as an EEP-ROM, an electronic component such as a semiconductor element for accessing the semiconductor memory, a substrate 143 for mounting the electronic component.

  The electronic circuit portion 141 is accommodated in a lower portion of a rotation speed sensor (not shown) near the center of the base portion 129 constituting the lower portion of the turbo molecular pump main body 100 and is closed by an airtight bottom lid 145.

  By the way, the position sensors such as the upper radial sensor 107, the lower radial sensor 108, and the axial sensor 109 described above can be configured by inductance type sensors or eddy current type sensors. Is extracted as the inductance of the sensor coil.

  That is, when the distance between the sensor and the rotating body 103 is different, the inductance of the sensor coil is different. Thus, since the sensor coil has a specific inductance corresponding to the distance between the sensor and the rotating body 103, the output voltage of the sensor has a specific frequency characteristic corresponding to the inductance.

  An equivalent circuit of the position sensor is shown in FIG. In FIG. 7, a sensor coil 1 is wound around the tip of the position sensor. A resistor 2 and a capacitor 3 are connected to the sensor coil 1 in series and in parallel, respectively. An oscillator 4 is connected to this circuit, and a high frequency voltage having a constant frequency and a constant voltage is applied to the sensor coil 1 from the oscillator 4 to generate a high frequency magnetic field.

  When the position sensor is constituted by an inductance type sensor, a magnetic body is fixed to the rotating body 103. When the magnetic body approaches the core of the sensor coil 1, a magnetic circuit having the magnetic body and the core as a magnetic path is formed, and the inductance of the sensor coil 1 changes according to the distance between the magnetic body and the core. To do. On the other hand, when the position sensor is composed of an eddy current sensor, a conductor is fixed to the rotating body 103. When this conductor approaches the sensor coil 1, an eddy current flows through the conductor due to the high-frequency magnetic field created by the sensor coil 1, and the sensor coil 1 is affected by the generation of the eddy current, The inductance changes according to the distance. Then, due to the change in the inductance of the sensor coil 1, the frequency characteristics (for example, the resonance frequency and the Q value (an index indicating the sharpness of resonance)) of the output voltage Eo of the position sensor change, and the amplitude of the output voltage Eo changes. That is, the output voltage Eo of the position sensor is subjected to amplitude modulation using the inductance of the sensor coil 1 as a mediating characteristic depending on the position of the rotating body 103 to which the magnetic body or conductor is fixed. By utilizing this phenomenon and measuring the output voltage Eo, the position of the rotating body 103 can be measured.

  FIG. 8 schematically shows the relationship between the frequency characteristics of the frequency fs (hereinafter referred to as carrier frequency) of the high-frequency voltage applied by the oscillator 4 and the output voltage Eo of the position sensor. The carrier frequency fs is constant, the resonance frequency fn and Q value of the output voltage Eo change depending on the position of the rotating body 103, and the value of the output voltage Eo changes. The detection area of the position sensor is effective with good sensitivity if it is a steep part (shown as a detection area in the figure) indicated by a solid line in the frequency characteristics indicated by the dotted line in the figure. Of these, it is desirable to match the carrier frequency fs with the steepest part.

In addition, there is another temperature sensor as a sensor using the change in inductance in this way.
This temperature sensor uses a phenomenon in which the magnetic permeability of the magnetic body installed in the rotating body 103 changes depending on the temperature of the magnetic body, and the inductance of the sensor coil 1, that is, the output voltage Eo changes accordingly. It has the same configuration as that of the position sensor.

In addition, a magnetic body having a Curie temperature equal to the allowable temperature of the rotating body 103 is disposed on the rotating body 103, and the magnetic permeability decreases greatly when the magnetic body reaches the Curie temperature. In other words, there is a technique that detects that the temperature of the rotating body 103 has exceeded the allowable temperature by utilizing a phenomenon that the output voltage Eo greatly decreases.
Further, the temperature sensor disclosed in Patent Document 1 includes a first magnetic body having a Curie temperature equal to the allowable temperature of the rotating body 103 and a second magnetic body having a Curie temperature higher than the allowable temperature. The temperature of the rotating body 103 exceeded the allowable temperature by installing and taking the difference between the two output voltages Eo amplitude-modulated by the change in the magnetic permeability of each of the first magnetic body and the second magnetic body. Is detected.

JP 2006-194094 A

  However, in general, the frequency characteristics of the output voltage Eo of these sensors are the permeability of the magnetic material fixed to the rotating body 103 or the resistance value of the conductor, the inductance of the sensor coil 1, the resistance value of the resistor 2, and the resistance value of the capacitor 3. Depending on the capacitance, the resistance value and capacitance of the cable connecting the control device in which the oscillator 4 is arranged and the vacuum pump body, variation in the mounting position of the sensor coil 1 or its core, etc. At the time of attachment, the steep portion of the frequency characteristic of the output voltage Eo of the sensor does not coincide with the carrier frequency fs.

For this reason, in order to obtain good sensor sensitivity, it is necessary to adjust the frequency characteristic of the output voltage Eo or amplify the output voltage Eo.
Conventionally, when adjusting the frequency characteristic of the output voltage Eo, this adjustment has been performed by mechanically adjusting the mounting position of the sensor coil 1 or its core at the time of factory manufacture. However, as will be described later, regarding the temperature sensor, when the cylindrical portion 102d of the rotator 103 exceeds the permissible temperature and becomes high in temperature, the strength decreases and the centrifugal force acting on itself may not be able to withstand destruction. In order to prevent this, it is desirable to measure the temperature of the cylindrical portion 102d and display an alarm or reduce or stop the rotation of the rotating body 103 according to the result. For this purpose, the sensor coil 1 or its core must be arranged at a location facing the cylindrical portion 102d. Such a location is a place where a human hand behind the vacuum pump cannot easily enter, and the sensor coil 1 Or, in order to adjust the mounting position of the core, the outer cylinder 127 and the rotating body 103 have to be frequently removed from the turbo molecular pump main body 100, and it has been necessary to perform an inefficient and time-consuming work.

  On the other hand, when the output voltage Eo is amplified, there is an upper limit on the output voltage of the amplifier due to restrictions such as the capacity of the power supply, the withstand voltage of the circuit elements, and the cost. When the output voltage of the amplifier reaches the upper limit and is saturated, the sensor cannot normally measure the position or temperature of the rotating body 103. As can be seen from FIG. 8, the sensor outputs a voltage even at the lower limit value of the detection region. This voltage is unnecessary for measurement, and can be canceled and eliminated by placing two sensors facing each other across the rotating body 103 and taking the difference between the values of these measurement signals. When measuring with one sensor and amplifying the sensor measurement signal, etc., this unnecessary voltage is also amplified to increase power consumption, or to increase the sensitivity of the sensor after amplification corresponding to the detection region To increase the range of the measurement signal value, an amplifier with a high output saturation voltage is required, and the cost of the vacuum pump is increased.

  Further, there is a problem even when the measurement signal of the sensor is converted into a digital value and various arithmetic processes are added to the digital value. That is, an A / D converter that converts an analog voltage into a digital value has an upper limit on the voltage that can be input. For this reason, when a voltage larger than this is input to the A / D converter, the A / D converter uniformly converts this voltage to the same value as the upper limit voltage, and the position or temperature cannot be measured normally. The / D converter cannot withstand the input voltage and breaks down. Furthermore, when the sensor outputs a voltage even at the lower limit of the detection region, and the range of the measurement signal value of the sensor corresponding to the measurement target range of the physical quantity is narrow, this measurement signal is input to the A / D converter. However, the sensitivity of the sensor could not be improved satisfactorily.

  Further, regarding the temperature sensor, since the inductance of the sensor coil 1 varies depending not only on the temperature of the rotating body 103 but also on the position, an error due to the position of the rotating body 103 occurs in the measurement signal of the sensor.

  The present invention has been made in view of such conventional problems, and in particular, to provide a vacuum pump capable of easily obtaining good sensor sensitivity and measurement signals without adjusting the sensor mounting position. Objective.

For this reason, the vacuum pump according to the present invention (Claim 1) includes a rotating part having a rotor and a cylindrical part and a conductor, a rotating part fixed to the rotating body, and a rotating part, Based on a non-rotating portion in which a sensor coil whose inductance changes with temperature changes is disposed, an oscillator that supplies a high-frequency voltage to the sensor coil, and a modulated voltage that is amplitude-modulated by the inductance change of the sensor coil A sensor circuit that outputs a measurement signal of the temperature, and a control for detecting the temperature of the rotating part based on a change due to a temperature change of the rotating part of an eddy current of the rotating part that generates a change in the inductance Configured with equipment.
Further, the vacuum pump according to the present invention (Claim 2) is configured to include a frequency characteristic variable means that enables the frequency characteristic of the modulated voltage to be changed.

  The vacuum pump is provided with a frequency characteristic variable means that enables the frequency characteristic of the modulated voltage to be changed, so that the frequency characteristic of the modulated voltage can be changed to a frequency band in which the slope of the curve is large. The frequency, ie, the carrier frequency can be adjusted. Thereby, good sensor sensitivity can be obtained without adjusting the position of the sensor coil or its core.

  Further, in the vacuum pump according to the present invention (Claim 3), the frequency characteristic variable means includes a variable capacitor and / or a variable resistor, and the variable capacitor and / or the variable resistor is connected to the sensor coil. Features.

By connecting a variable capacitor or variable resistor to the sensor coil and adjusting the capacitance or resistance, the frequency characteristic of the modulated voltage can be adjusted and the frequency characteristic variable means can be realized at low cost. Can do.
As the variable capacitor or variable resistor, for example, a type in which the capacitance or resistance value is changed continuously or stepwise by rotating or sliding the movable piece, or the capacitance of the capacitance via a select switch to the sensor coil. A configuration in which a plurality of different capacitors or a plurality of resistors having different resistance values are connected, and a capacitor or a resistor connected to the sensor coil with this select switch is switched, a capacitor or a resistor is detachably connected, and a capacitor having a suitable capacitance or The structure etc. which replace | exchange for resistance of suitable resistance value are mention | raise | lifted.

  Furthermore, the vacuum pump according to the present invention (Claim 4) is configured to include an oscillation frequency variable means that enables the frequency of the high-frequency voltage to be changed.

  By providing the oscillation frequency variable means that enables the frequency of the high-frequency voltage supplied by the oscillator to be changed, the frequency of the high-frequency voltage, that is, the carrier frequency is set in a frequency band in which the slope of the frequency characteristic curve of the modulated voltage is large. Can be adjusted. Thereby, good sensor sensitivity can be obtained without adjusting the position of the sensor coil or its core.

  Furthermore, the vacuum pump according to the present invention (Claim 5) includes a reference value signal generating means for generating a reference value signal of the measurement signal, a difference signal between the measurement signal and the reference value signal, or the difference. Sensor output differential means for outputting the amplified signal is provided.

  Furthermore, the vacuum pump according to the present invention (Claim 6) includes a reference value signal variable means that enables the value of the reference value signal to be changed.

  The reference value signal generating means generates a reference value signal of the measurement signal, and the sensor output differential means outputs a signal of a difference between the values of the measurement signal and the reference value signal or a signal obtained by amplifying the difference, thereby obtaining a physical quantity. A value lower than the reference value signal is excluded from the measurement target, and the entire range of the output signal of the vacuum pump can be made to correspond to a range of values greater than or equal to the value of the physical quantity reference value signal.

  As a result, sensor sensitivity is improved, and even when the measurement signal is amplified by an amplifier, unnecessary values of the measurement signal are not amplified, so that power consumption can be reduced and an amplifier with a high output saturation voltage is not required. Further, the increase in cost of the apparatus can be mitigated.

  Examples of the reference value signal generating means include an electric circuit having a capacitor or a resistor as a circuit element. In this case, the terminal voltage of the capacitor or resistor can be used as the reference value signal.

  Further, the reference value signal generating means includes reference value signal variable means that enables the value of the reference value signal to be changed, so that the magnetic permeability or the resistance value of the conductor, the inductance of the sensor coil, and the sensor circuit It is possible to correct the setting error of the measurement target range of the physical quantity due to variations in the characteristics of the oscillator and the like, or to adjust the measurement target range of the physical quantity according to the measurement conditions.

  Furthermore, the vacuum pump according to the present invention (invention 7) is characterized in that the reference value signal variable means includes a variable resistor.

  When the reference value signal generation circuit is configured with, for example, a capacitor or a resistor, and the voltage between terminals of the capacitor or the resistor is used as a reference value signal, at least a part of the capacitor or the resistor is a variable capacitor or a variable resistor. To do. Thereby, the reference value signal variable means can be configured at low cost.

  Furthermore, the vacuum pump according to the present invention (invention 8) is characterized in that the sensor output differential means can change the amplification factor of the difference signal between the measurement signal and the reference value signal. A variable means is provided.

  The sensor output differential means includes a difference signal gain variable means that enables a change of the signal gain of the difference between the value of the measurement signal and the reference value signal, whereby the magnetic permeability or the resistance value of the conductor. Even if the sensor sensitivity changes due to the inductance of the sensor coil, the characteristics of the sensor circuit and the oscillator, etc., it can be adjusted to an appropriate sensitivity.

  Furthermore, the vacuum pump according to the present invention (invention 9) includes filter means for attenuating a frequency band component of displacement of the rotating body of the signal based on the modulated voltage, and the measurement signal is passed through the filter means. Is output.

  Generally, the temperature of the measurement object varies at a frequency lower than the position of the measurement object. The vacuum pump includes filter means for attenuating a component in a predetermined frequency band of the signal based on the modulated voltage, and outputs a measurement signal through the filter means, whereby the object to be measured included in the temperature measurement signal is output. It is possible to reduce an error due to a change in position. As the filter means, in a magnetic bearing device and a vacuum pump, which will be described later, for example, a low-pass filter having a cut-off frequency that is lower than the rotational speed frequency of the rotating body or the rotating part may be used.

  Furthermore, the magnetic levitation device according to the present invention is a magnetic levitation device equipped with a physical quantity measuring device, the magnetic levitation device is levitated and supported by a magnetic force, and has the magnetic body or the conductor, A non-floating portion having a magnet for generating a magnetic force and provided with the sensor coil and a control device provided with the oscillator may be provided.

  This makes it possible to provide a magnetic levitation device that exhibits the effects of the physical quantity measurement device of the above invention.

  Furthermore, the magnetic levitation apparatus according to the present invention may be characterized in that the frequency characteristic varying means is disposed on the non-levitation part.

  Furthermore, the magnetic levitation apparatus according to the present invention may be characterized in that the oscillation frequency varying means is disposed on the non-levitation portion.

  Most of the magnetic levitation devices are composed of a mechanism unit body composed of a floating part and a non-floating part, a control device, and a cable that electrically connects them. By disposing the frequency characteristic varying means or the oscillation frequency varying means not on the control device but on the non-floating part of the mechanism body, the magnetic permeability or the resistance value of the conductor disposed on the floating part and the non-floating part Variations in sensor sensitivity caused by variations in sensor coils disposed on the flying surface can be adjusted by the mechanism unit body to fall within a predetermined range.

  Thereby, it is not necessary to adjust the sensor sensitivity according to the combination of the mechanism unit body and the control device, and compatibility between the mechanism unit body and the control device can be improved. Then, when replacing either the mechanism main unit or the control device due to a failure, an engineer goes to the installation location of the magnetic levitation device and adjusts the sensor sensitivity with the equipment necessary for adjustment such as a measuring instrument. The work to be performed can be reduced or simplified.

  Furthermore, the magnetic levitation apparatus according to the present invention may be characterized in that the reference value signal variable means is disposed on the non-floating portion.

  By disposing the reference value signal variable means on the non-floating portion of the mechanism unit body, the magnetic unit permeability or the resistance value of the conductor, the inductance of the sensor coil, the characteristics of the sensor circuit and the oscillator can be obtained. It is possible to correct the setting error of the measurement target range of the physical quantity due to variation or the like so that it falls within a predetermined range, or to adjust the measurement target range of the physical quantity according to the measurement conditions of the physical quantity measurement device.

  Thereby, it is not necessary to adjust the range of the physical quantity value of the floating part corresponding to the range of the value of the measurement signal output from the sensor circuit according to the combination of the mechanism unit body and the control device. Compatibility can be improved. Then, when replacing either the mechanism main unit or the control device due to a failure, an engineer will bring the necessary equipment for adjustment, such as a measuring instrument, to the installation site of the magnetic levitation device and subject to physical quantity measurement. The work of adjusting the range can be reduced or simplified.

  Furthermore, the magnetic levitation apparatus according to the present invention may be characterized in that the difference signal gain variable means is disposed on the non-floating portion.

  By disposing the differential signal amplification factor variable means on the non-floating portion of the mechanism body, the mechanism body has a magnetic permeability or a resistance value of the conductor, the inductance of the sensor coil, the characteristics of the sensor circuit and the oscillator. It is possible to adjust so that variations in sensor sensitivity due to variations in the range fall within a predetermined range.

  Thereby, it is not necessary to adjust the sensor sensitivity according to the combination of the mechanism unit body and the control device, and compatibility between the mechanism unit body and the control device can be improved. Then, when replacing either the mechanism main unit or the control device due to a failure, an engineer goes to the installation location of the magnetic levitation device and adjusts the sensor sensitivity with the equipment necessary for adjustment such as a measuring instrument. The work to be performed can be reduced or simplified.

  Furthermore, the magnetic levitation apparatus according to the present invention may comprise a threshold value setting means for setting a threshold value for the physical quantity.

  Thereby, it is possible to identify whether or not the physical quantity of the floating part of the magnetic levitation apparatus exceeds the threshold value. In addition, the magnetic levitation device may be provided with a storage device such as a memory for recording when the physical quantity of the flying height exceeds a threshold value, or an alarm device for displaying an alarm. As a threshold value, it can be set as the allowable value of the position of a floating part, a displacement, and temperature, for example.

  Furthermore, the magnetic levitation device according to the present invention is configured such that the frequency characteristics of the modulated voltage and the frequency of the high-frequency voltage depend on the inductance, capacitance, and resistance of the cable connecting the non-floating portion and the control device. The control device may be provided with a correcting means for correcting at least one of the value of the modulated voltage and the value of the measurement signal.

As described above, many of the magnetic levitation devices are configured by a mechanism unit body, a control device, and a cable that electrically connects them. When the oscillator is arranged in the control device and the sensor coil is arranged in the non-floating portion, these are connected via the cable, so that the inductance, capacitance, and resistance of the cable change. The frequency characteristic of the modulated voltage will change.
Further, the length of the cable may be inevitably changed depending on the installation layout of the magnetic levitation device. In this case, the inductance, capacitance, and resistance of the cable change. The control device is provided with correction means for correcting at least one of the frequency characteristics of the modulated voltage, the frequency of the high-frequency voltage supplied by the oscillator, the modulated voltage, and the value of the measurement signal output from the sensor circuit. By doing so, a change in sensor sensitivity due to a change in the length of the cable can be corrected.

  Examples of the magnetic levitation device include a magnetic bearing device that magnetically levitates a rotating body and supports it, and a magnetic levitation type vibration isolation device that magnetically levitates a vibration isolation table.

  Furthermore, the vacuum pump according to the present invention includes a rotating part having a magnetic material or a conductor, a non-rotating part in which a sensor coil whose inductance changes with a change in a physical quantity of the rotating part, and a sensor coil. A control device may be provided that includes an oscillator that supplies a high-frequency voltage and a sensor circuit that outputs a measurement signal of the physical quantity based on a modulated voltage that is amplitude-modulated by an inductance change of the sensor coil. Good.

  Furthermore, the vacuum pump according to the present invention may be characterized in that the physical quantity is at least one of the position, displacement, and temperature of the rotating part.

  Furthermore, the vacuum pump according to the present invention may include a filter unit that attenuates a component in a predetermined frequency band of a signal based on the modulated voltage, wherein the physical quantity is the temperature of the rotating unit. .

  Furthermore, the vacuum pump according to the present invention (Claim 10) is characterized in that the frequency characteristic varying means is disposed in the non-rotating portion.

  Furthermore, the vacuum pump according to the present invention (invention 11) is characterized in that the oscillation frequency varying means is disposed in the non-rotating portion.

  Furthermore, the vacuum pump according to the present invention (Claim 12) is characterized in that the reference value signal varying means is disposed in the non-rotating portion.

  Furthermore, the vacuum pump according to the present invention (invention 13) is characterized in that the difference signal amplification factor varying means is disposed in the non-rotating portion.

  Furthermore, the vacuum pump according to the present invention (invention 14) is provided with threshold setting means for setting a threshold for the temperature.

  At least one of the frequency characteristic variable means, the oscillation frequency variable means, the reference value signal variable means, and the threshold value setting means is disposed, for example, on the inner periphery of the bottom lid 145 of the turbo molecular pump in FIG. To do. Thereby, the operator can easily adjust at least one of the sensor sensitivity, the physical quantity measurement target range, and the threshold value by simply removing the bottom cover 145, and the vacuum pump main body and the control device. Compatibility can be improved.

  Furthermore, the vacuum pump according to the present invention (invention 15) includes a frequency characteristic of the modulated voltage according to the inductance, capacitance, and resistance of a cable connecting the non-rotating part and the control device, The control device includes a correction unit that corrects at least one of the frequency of the high-frequency voltage, the value of the modulated voltage, and the value of the measurement signal.

  This makes it possible to provide a vacuum pump that has the same effects as the physical quantity measuring device or the magnetic levitation device of the above invention.

  Furthermore, the vacuum pump according to the present invention (invention 16) includes a rotating part having the conductor on the inner peripheral side or lower end of a cylindrical part, and the sensor coil or the core of the sensor coil facing the conductor. A non-rotating portion provided and a control device provided with the oscillator are provided.

  Further, in the vacuum pump according to the present invention (invention 17), the opposing surface of the conductor facing the sensor coil or the core of the sensor coil is perpendicular to the rotation center axis of the rotating portion. Features.

  For example, when the turbo molecular pump having the configuration of FIG. 6 is used in a semiconductor manufacturing apparatus, the cylindrical portion 102d of the rotating body 103 is used to exhaust process gas continuously supplied into the chamber of the semiconductor manufacturing apparatus. The temperature of the cylindrical portion 102d rises due to friction between the gas and the process gas.

  When the temperature of the cylindrical portion 102d rises, the cylindrical portion 102d increases the residual strain in the circumferential direction due to the centrifugal force acting on the cylindrical portion 102d, and the outer peripheral diameter increases to come into contact with the threaded spacer 131. The material strength decreases, and it cannot withstand centrifugal force and breaks.

  In order to prevent these problems, the turbo molecular pump continuously or periodically measures the temperature of the cylindrical portion 102d during operation, and displays an alarm or rotation when the temperature exceeds a threshold value. It is desirable to reduce or stop the rotation of the body 103.

Instead of measuring the temperature of the cylindrical portion 102d, a relational expression between the temperature of the predetermined portion of the rotating body 103 and the temperature of the cylindrical portion 102d is obtained in advance by an experiment, and the temperature of the predetermined portion is measured. Although the temperature of the cylindrical portion 102d may be calculated based on the relational expression, in this case, the relational expression varies depending on the type and flow rate of the process gas, the temperature of the rotating body 103, and the like. Based on the results of this experiment, the relational expression must be corrected according to these conditions when the turbo molecular pump is operating.
Therefore, it is desirable to place the magnetic body or conductor in the cylindrical portion 102d and directly measure the temperature of the cylindrical portion 102d. However, if the magnetic body or conductor is disposed on the outer peripheral side of the cylindrical portion 102d, the magnetic body or conductive body is disposed. If the direction of the centrifugal force acting on the body is a direction that separates the magnetic body or conductor from the cylindrical portion 102d and the fixing strength for fixing the magnetic body or conductor to the cylindrical portion 102d decreases due to a change over time, the magnetic body or conductive The body may fall off the cylindrical portion 102d. Further, most of the process gas of the semiconductor manufacturing apparatus is corrosive, and the outer peripheral side of the cylindrical portion 102d is a flow path of the process gas. Therefore, the magnetic body or the conductor is exposed to the process gas and corrodes. .

For this reason, the vacuum pump of this invention arrange | positions a magnetic body or a conductor to the inner peripheral side of the cylindrical part of a rotation part. Thereby, the direction of the centrifugal force acting on the magnetic body or conductor becomes the direction of pressing the magnetic body or conductor against the cylindrical portion 102d, and the fixing strength for fixing the magnetic body or conductor to the cylindrical portion 102d is reduced. The magnetic body or the conductor is less likely to drop off from the cylindrical portion 102d. Further, in order to prevent corrosion, a purge gas such as nitrogen is introduced into the electrical part through a purge port provided in the base 129, and this purge gas is introduced into the cylindrical part from the shaft hole opening at the upper end of the housing 122 of the electrical part. It passes between the inner peripheral surface of 102d and the outer peripheral surface of the housing 122, and merges with the process gas at the lower end of the cylindrical portion 102d. Due to the flow of the purge gas, the process gas hardly enters the inner peripheral side of the cylindrical portion 102d, and corrosion of the magnetic body or the conductor can be reduced.
When the temperature of the cylindrical portion 102d exceeds the threshold value, the turbo molecular pump displays an alarm, outputs an alarm signal to a device linked to the turbo molecular pump, or decelerates the rotation of the rotating body 103. Or stop.

  Furthermore, as described above, in the turbo molecular pump, when the temperature of the cylindrical portion 102d rises, the residual strain in the circumferential direction increases due to the centrifugal force acting on the cylindrical portion 102d, and the cylindrical portion 102d swells to the outer peripheral side. It transforms with. As a result, the inner peripheral diameter di of the cylindrical portion 102d also increases, and the distance between the sensor coil 1 and the magnetic body or conductor increases, and the inductance changes. As a result, an error occurs in the temperature detection value.

  For this reason, the vacuum pump of the present invention may be configured as shown in FIG. That is, the surface of the magnetic body or conductor m1 disposed in the cylindrical portion 102d facing the sensor coil 1 or its core 1c is perpendicular to the rotation center axis OO ′ of the rotating body 103. . Then, the sensor coil 1 or the core 1c is disposed in the non-rotating portion so as to face the magnetic body or the conductor m1 in a direction parallel to the rotation center axis O-O ′ during the rotation of the rotating body 103. Thereby, even if the cylindrical portion 102d is deformed to the outer peripheral side, the change in the distance between the magnetic body or conductor m1 and the sensor coil 1 or the core 1c is small, so that the occurrence of an error in the temperature detection value can be reduced. Further, the magnetic body or conductor of the sensor coil 1 or the core 1c has a size in the radial direction perpendicular to the rotation center axis OO ′ of the magnetic body or conductor m1, particularly toward the inner peripheral side of the cylindrical portion 102d. By making it larger than the portion facing m1, even if the cylindrical portion 102d is deformed to the outer peripheral side, the facing area between the magnetic body or conductor m1 and the sensor coil 1 or core 1c is secured to a level that does not cause any functional problems. Can do. Further, since the deformation of the cylindrical portion 102d is larger as the position is closer to the lower end thereof, the influence of the deformation of the cylindrical portion 102d is further increased by disposing the magnetic body or the conductor m1 on the inner peripheral side of the cylindrical portion 102d. Can be small.

  Further, when the corrosion of the magnetic material or the conductor by the process gas is acceptable, as shown in FIG. 10, the magnetic material or the conductor m1 is disposed at the lower end of the cylindrical portion 102d, and the sensor coil 1 or The core 1c may be disposed in the non-rotating portion so as to face the magnetic body or the conductor m1 in a direction parallel to the rotation center axis OO ′ during the rotation of the rotating body 103. Also in this case, the cylindrical portion 102d is formed on the outer periphery by increasing the radial direction perpendicular to the rotation center axis OO ′ of the magnetic body or conductor m1 to the inner peripheral side of the cylindrical portion 102d. Even if it is deformed to the side, the facing area between the magnetic body or conductor m1 and the sensor coil 1 or core 1c can be ensured sufficiently and sufficiently.

  Furthermore, in the vacuum pump according to the present invention (invention 18), the rotating part is placed at a position on a plane assumed to pass through the rotation center axis of the rotating part and the conductor, a thick part, a thin part. It has at least any one of the parts.

  If the magnetic body or conductor is placed in the rotating part, the mass of the magnetic body or conductor is added, causing imbalance in the rotating part, and the vacuum pump vibrates or has a large bearing force or high bearing. A strong bearing is required or the life of the bearing is reduced. For this reason, the vacuum pump of the present invention has at least one of a weight, a thick part, and a thin part at a position on a plane assumed to pass through the rotation center axis and the magnetic body or conductor. Have one. Examples of the weight include a metal material such as corrosion-resistant stainless steel, a non-metal material such as a resin material, and a thermosetting adhesive.

  Furthermore, the vacuum pump according to the present invention (invention 19) is characterized in that the conductor is arranged or formed on the object with respect to the rotation center axis of the rotating part.

  For example, when the magnetic body or the conductor is formed into a target circular shape or ring shape with respect to the rotation center axis of the rotating portion, or when the magnetic body or the conductor is divided and arranged, the rotation center axis of the rotating portion is On the plane assumed to be vertical, a pair is formed so as to sandwich the rotation center axis of the rotation unit, and the rotation unit is arranged in the rotation unit.

  Thereby, the unbalance of the rotation part which arises by having added the mass of the magnetic body or the conductor can be reduced.

  Furthermore, the vacuum pump according to the present invention (invention 20) is characterized in that at least one of the conductor and the weight is sealed by a sealing means.

  Thereby, even if the process gas of the semiconductor manufacturing apparatus enters the inner peripheral side of the rotating portion against the above-described purge gas flow, corrosion of the magnetic body or the conductor can be reduced. Examples of the sealing means include plating, a coating, a coating material, a molding material, an adhesive, a container, a corrosion-resistant surface layer of a magnetic body or a conductor.

  Furthermore, the vacuum pump according to the present invention (invention 21) is characterized in that at least one of the conductor and the weight is fixed to the rotating portion with a thermosetting adhesive.

  Adhering a magnetic material, conductor, or mass to a rotating part with a thermosetting adhesive, and heating the adhesive with a warm air device such as a dryer shortens the adhesive curing time and manufactures a vacuum pump The process can be made efficient.

  As described above, according to the present invention, it is possible to easily obtain a good sensor sensitivity and measurement signal without adjusting the sensor mounting position.

Hereinafter, embodiments of the present invention will be described. FIG. 1 shows an equivalent circuit of the position sensor 10 according to the first embodiment of the present invention. Each of the upper radial position sensor 107, the lower radial position sensor 108, and the axial position sensor 109 is represented by the equivalent circuit of FIG.
The same elements as those in FIG. 7 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 1, a variable resistor 5 and a variable capacitor 6 are connected to the sensor coil 1 as frequency characteristic variable means. The sensor coil 1 is disposed so as to face the rotating body 103, and the inductance changes according to the position of the magnetic body or the conductor fixed to the rotating body 103. The high frequency voltage supplied from the oscillator 4 is amplitude-modulated by the inductance change of the sensor coil 1. As the frequency of the high frequency voltage, a frequency of 10 k to 10 MHz or higher is used.

  The amplitude-modulated modulated voltage is converted into a DC voltage by the rectifier circuit 7 and input to the amplifier 8. The amplifier 8 amplifies and outputs the input DC voltage. The amplification degree k can be adjusted by the variable resistor 9. The variable resistor 5 and the variable capacitor 6 are disposed inside the vacuum pump body.

  In such a configuration, by adjusting the variable resistor 5 and the variable capacitor 6, the frequency characteristic of the modulated voltage is changed to change the resonance frequency fn and the Q value. At this time, adjustment is preferably performed so that the carrier frequency matches the maximum slope portion so that the carrier frequency enters the detection region that is the slope portion of the frequency characteristic.

  As a result, it is not necessary to adjust the mechanical position of the sensor coil 1 or its core as in the prior art, and it is possible to easily adjust the sensitivity of the sensor simply by adjusting the variable resistor 5 and the variable capacitor 6. Can do.

  For this reason, it is only necessary to adjust the circuit on the substrate even when the position sensor is structurally disposed inside the vacuum pump where it is difficult for human hands to enter.

  Note that the frequency characteristic of the modulated voltage is adjusted by adjusting the variable resistor 5 and the variable capacitor 6, but the carrier frequency side is not fixed but variable, and the frequency characteristic of the modulated voltage is good. The sensitivity of the sensor may be adjusted.

  Next, a second embodiment of the present invention will be described. Note that the same elements as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  FIG. 2 is an equivalent circuit of a temperature sensor that measures the temperature of the rotating body 103 in a non-contact manner. This temperature sensor is also constituted by an inductance type sensor or an eddy current type sensor. In the case of being constituted by an inductance type sensor, a magnetic body is arranged in the temperature measurement part of the rotating body 103, and when the temperature of the rotating body 103 changes, the magnetic permeability of the magnetic body changes, and the inductance of the sensor coil 1 changes. Changes. On the other hand, in the case of an eddy current sensor, a conductor is disposed in the temperature measurement portion of the rotating body 103, and when the temperature of the rotating body 103 changes, the resistance of the conductor changes, and accordingly. The magnitude of the eddy current flowing through the conductor also changes, and the inductance of the sensor coil 1 changes.

In FIG. 2, a DC voltage V1 converted from a modulated voltage by the rectifier circuit 7 is inputted to an input terminal 21 of a differential amplifier 20 as a sensor output differential means.
This modulated voltage is adjusted in sensitivity by the variable resistor 5 and the variable capacitor 6. On the other hand, a reference value signal voltage V2 as a reference value signal is input to the input terminal 22. The differential amplifier 20 outputs a voltage VO obtained by amplifying the difference between the input DC voltage V1 and the reference value signal voltage V2 to the output terminal 23. The amplification factor of the differential amplifier 20 is determined by the resistance values of the resistors R1 and R2. The voltage VO is output through a low-pass filter (not shown) having a cutoff frequency of 1 Hz or less as a filter means. Further, the value of the reference value signal voltage V2 is set to be equal to the value of the DC voltage V1 corresponding to the lower limit value of the temperature measurement target range of the rotator 103, and the entire range of the output signal value of the sensor is set to the temperature. Correspond to the measurement target range.

  As a result, sensor sensitivity is improved, and even when the sensor measurement signal is amplified by an amplifier, the measurement signal value corresponding to a value lower than the lower limit value of the temperature measurement target range is not amplified. Since power can be reduced and an amplifier with a high output saturation voltage is not required, the cost increase of the temperature sensor can be mitigated. Furthermore, temperature measurement errors due to fluctuations in the position of the rotator 103 can be reduced.

  The reference value signal voltage V2 can be adjusted by a reference value signal voltage variable circuit 30 (not shown) serving as a reference value signal variable means. This corrects the setting error of the temperature measurement target range due to variations in the magnetic permeability or conductor resistance and the characteristics of the sensor circuit, oscillator, etc., and this measurement target range can be changed according to the measurement conditions. Can be adjusted.

  The temperature sensor can be arranged at a location as shown in FIG. That is, the magnetic body or the conductor is fixed to at least one of the locations 11A, 11B, 11C, 11D and the like inside the rotating body 103, and the locations 12A, 12B, 12C outside the housing 122 of the electrical component section are fixed. The sensor coil 1 or its core is disposed at a position facing the magnetic body or conductor fixed to the rotating body 103 such as 12D. The location where the sensor coil 1 or its core is disposed is a place where it is difficult for human hands to enter, but the sensor sensitivity can be obtained without the need for mechanical position adjustment of the sensor coil 1 or its core due to the above configuration. Can be adjusted appropriately. The magnetic body or the conductor is coated with a corrosion-resistant coating so as to be sealed from the process gas, and is fixed to the rotating body 103 with a thermosetting adhesive.

Furthermore, it is desirable for the rotating body 103 to reduce unbalance caused by fixing the magnetic body or the conductor. Examples of this case are shown in FIGS. 4 (A) and 4 (B). FIG. 4B is a cross-sectional view taken along the line PP ′ of FIG. 4A is a cross-sectional view taken along the line QQ ′ of FIG.
4A and 4B, the rotation center axis OO ′ of the rotator 103 (the description of the rotor shaft 113 is omitted for the sake of clarity) and the magnetic body or conductor m1 ( In the figure, the position on the plane PP ′ assumed through the left cross hatched portion), and the target position m2 (in the figure, with respect to the magnetic substance or conductor m1 and the rotation center axis OO ′). A stainless steel weight 150 (not shown) having a mass equivalent to that of the magnetic material or the conductor m1 is fixed to the right cross hatched portion with a thermosetting adhesive. Instead of fixing the weight 150 to the rotating body 103, the magnetic body or the conductor is made into a target circular shape or ring shape M (a hatched portion including m1 and m2 in the drawing) with respect to the rotation center axis OO ′. Alternatively, the rotation center axis OO ′ may be divided into target positions m1 and m2 and arranged. Or you may provide a thin part in the rotary body 103 by stealing the part etc. which were each surrounded by the dotted line of a, b, and c of the rotary body 103. FIG. When the magnetic body or conductor is not the target circular shape or ring shape M with respect to the rotation center axis OO ′, the sensor coil 1 is intermittently synchronized with the rotation of the rotating body 103. Or confront the conductor. In this case, based on the output signal of the rotation angle sensor for the commutation control of the motor, the time when the sensor coil 1 faces the magnetic material or the conductor is specified, and the temperature may be measured at this time.

  Next, a third embodiment of the present invention will be described. The third embodiment of the present invention uses the temperature sensor of the second embodiment described above, and when the temperature of the magnetic body fixed to the rotating body 103 exceeds the Curie temperature, the magnetic permeability of the magnetic body is An abnormally high temperature of the rotating body 103 is detected by utilizing a phenomenon that rapidly decreases. Since the equivalent circuit of the temperature sensor of this embodiment is the same as that of the second embodiment, the description thereof is omitted.

  FIG. 5 shows the relationship between the temperature of the magnetic material and the inductance of the sensor coil. Inductance decreases rapidly when the temperature of the magnetic material exceeds the Curie temperature. For this reason, as indicated by the alternate long and short dash line in the figure, an inductance threshold value is set so that a temperature abnormality can be detected when the Curie temperature is exceeded.

  However, as shown in FIG. 5, at a temperature lower than the Curie temperature, the inductance decreases as the temperature decreases, so that the threshold value intersects the temperature-inductance characteristic curve only when the temperature exceeds the Curie temperature. With this setting, the settable range (between the dotted lines between the upper and lower sides) is narrow. In consideration of the magnetic permeability of the magnetic material and the variation in the characteristics of the sensor circuit and the oscillator, it becomes even narrower.

  However, as described in the second embodiment, the frequency characteristic of the modulated voltage is adjusted using the variable resistor 5 and the variable capacitor 6, and the modulated voltage is converted into the DC voltage V1 by the rectifier circuit 7. The voltage V1 and the reference value signal voltage V2 are input to the differential amplifier 20, and the differential amplifier 20 outputs a voltage VO obtained by amplifying the difference between the DC voltage V1 and the reference value signal voltage V2, thereby reducing the threshold value. The settable range is wide. In this case, since the voltage VO may be saturated at a temperature corresponding to an inductance larger than the dotted line in the upper part of FIG. 5, the amplification factor of the differential amplifier 20 can be increased.

  As a result, the threshold value can be easily set and an amplifier with a high output saturation voltage is not required, so that the cost of the vacuum pump can be reduced.

  This is because the first and second magnetic bodies are arranged on the rotating body of the turbo molecular pump introduced in Patent Document 1 of the prior art, and the difference between the amplitude signals of the respective modulated voltages is obtained. Even in the configuration of detecting that the body temperature exceeds the Curie temperature, the same effect can be obtained by applying this embodiment.

  That is, it is desirable that the difference between the amplitude signals is zero at a temperature lower than the Curie temperature of both the first and second magnetic bodies, but the temperature-inductance characteristic curves of both magnetic bodies are matched with high accuracy. Due to the difficulty in manufacturing and the variation in magnetic permeability, the difference in amplitude signal does not become zero and has a large variation.

  For this reason, the settable range of the threshold for determining that the difference in the amplitude signal has changed due to one of the magnetic bodies exceeding its Curie temperature is narrowed, and erroneous detection of abnormally high temperatures is likely to occur. Even when the amplitude signal difference is amplified for improvement, it is necessary to amplify the offset component of the amplitude signal difference generated before one of the magnetic bodies exceeds the Curie temperature, and the power consumption increases. Or an amplifier with a high output saturation voltage is required, and the cost of the vacuum pump is increased.

  However, the difference between the amplitude signals is input to the input terminal 21 of the differential amplifier 20, and the reference value signal voltage V2 is used as the amplitude signal when the temperature of the rotating body is lower than the Curie temperature of both the first and second magnetic bodies. Thus, the differential amplifier 20 cuts most of the unnecessary offset components and outputs the amplified voltage of the difference between the amplitude signals to the output terminal 23. Further, by adjusting the reference value signal voltage V2, the variation of the amplified voltage can be kept within a predetermined range.

  As a result, the threshold value can be set easily, false detection of abnormally high temperature and power consumption are reduced, and an amplifier with a high output saturation voltage is not required, so that the cost increase of the vacuum pump can be mitigated.

  In the first and second embodiments, the variable resistor 5 and the variable capacitor 6 or the oscillation frequency variable means are arranged in the non-rotating part of the vacuum pump main body, and the sensitivity of the sensor is set within a predetermined range at the time of factory manufacture. By adjusting it so that it is within, the compatibility between the vacuum pump body and the controller can be improved. Further, in the second and third embodiments, the variable amplifier 5 and the variable capacitor 6 or the oscillation frequency variable means, the differential amplifier 20 and the reference value signal voltage variable circuit 30 are provided in the non-rotating part of the vacuum pump body. By arranging and adjusting the output voltage of the differential amplifier 20 to be within a predetermined range at the time of factory manufacture, the compatibility between the vacuum pump main body and the controller can be further improved. As a result, when replacing either the vacuum pump main body or the controller due to a failure or the like, the technician can carry the necessary equipment such as a measuring instrument and reduce the work of adjusting the sensor by going to the installation site of the vacuum pump. It can be simplified.

By the way, although the physical quantity measuring apparatus of the present invention has been described by taking as an example the case where the value of the measurement signal increases when the value of the physical quantity to be measured increases, the magnitude relationship between the carrier frequency fs and the resonance frequency fn of the modulated voltage. Depending on (fs <fn, or fs> fn) and the physical quantity to be measured, the value of the measurement signal may decrease when the value of the physical quantity increases. In this case, in the design of the physical quantity measuring device, a subtracting circuit for changing the magnitude relationship between the carrier frequency fs and the resonance frequency fn of the modulated voltage or subtracting the DC voltage converted from the modulated voltage from a predetermined voltage is provided. For example, the value of the measurement signal can be increased when the value of the physical quantity is increased.
Furthermore, when the physical quantity measuring device is composed of an eddy current sensor, if the object to be measured is formed of a conductor material suitable for physical quantity measurement, the object to be measured and the conductor of the physical quantity measuring device are integrated. Can be configured.
And it cannot be overemphasized that this invention includes these modifications.

Equivalent circuit of the sensor sensitivity adjustment circuit according to the first embodiment of the present invention Equivalent circuit of sensor sensitivity adjustment circuit according to second embodiment of the present invention Location of temperature sensor Installation location of magnetic body or conductor and weight to reduce unbalance Relationship between temperature of magnetic material and inductance of temperature sensor Longitudinal section of turbo molecular pump body Equivalent circuit of position sensor Relationship between carrier frequency of oscillator and frequency characteristics of sensor output voltage Another example of arrangement of magnetic material or conductor and sensor coil (longitudinal sectional view) Another example of arrangement of magnetic coil or conductor and sensor coil (longitudinal sectional view)

DESCRIPTION OF SYMBOLS 1 Sensor coil 2 Resistance 3 Capacitor 4 Oscillator 5, 9 Variable resistance 6 Variable capacitor 7 Rectifier circuit 8 Amplifier 11A, 11B, 11C, 11D Arrangement position 12A, 12B, 12C, 12D of magnetic body or conductor Arrangement position 20 Differential amplifier 21, 22 Input terminal 23 Output terminal 30 Reference value signal voltage variable circuit 100 Turbo molecular pump main body 103 Rotating body 102d Rotating body cylindrical portion 104 Upper radial electromagnet 105 Lower radial electromagnet 106 Axial electromagnet 107 Upper radial position sensor 108 Lower radial position sensor 109 Axial position sensor 113 Rotor shaft 121 Motor 141 Electronic circuit unit 143 Substrate 150 Weight 160 Connector

Claims (21)

A rotating part including a rotor and a rotating part having a cylindrical part and a conductor, and a rotor shaft fixed to the rotating body;
A non-rotating portion provided with a sensor coil whose inductance changes with a change in temperature of the rotating body;
An oscillator that supplies a high-frequency voltage to the sensor coil and a sensor circuit that outputs a measurement signal of the temperature based on a modulated voltage amplitude-modulated by an inductance change of the sensor coil are disposed, and the change in the inductance is detected. A vacuum pump, comprising: a control device that detects the temperature of the rotating unit based on a change in the eddy current of the rotating unit to be generated due to a temperature change of the rotating unit. 2. The vacuum pump according to claim 1, further comprising a frequency characteristic variable means that enables the frequency characteristic of the modulated voltage to be changed. The frequency characteristic variable means includes a variable capacitor and / or a variable resistor,
The vacuum pump according to claim 2, wherein the variable capacitor and / or the variable resistor is connected to the sensor coil. The vacuum pump according to any one of claims 1 to 3, further comprising an oscillation frequency varying unit that enables the frequency of the high-frequency voltage to be changed. Reference value signal generating means for generating a reference value signal of the measurement signal;
The sensor output differential means which outputs the signal of the difference of the value of the said measurement signal and the said reference value signal, or the signal which amplified the difference was provided, The Claim 1 characterized by the above-mentioned. Vacuum pump. 6. The vacuum pump according to claim 5, further comprising a reference value signal variable means for changing the value of the reference value signal. 7. The vacuum pump according to claim 6, wherein the reference value signal varying means includes a variable resistor. 8. The sensor output differential means comprises difference signal gain variable means for enabling change of the gain of the difference signal between the measurement signal and the reference value signal. The vacuum pump as described in any one of. 9. The method according to claim 1, further comprising filter means for attenuating a frequency band component of displacement of the rotating body of the signal based on the modulated voltage, and outputting the measurement signal via the filter means. A vacuum pump according to claim 1. The vacuum pump according to any one of claims 2 to 9, wherein the frequency characteristic varying means is disposed in the non-rotating portion. The vacuum pump according to any one of claims 4 to 10, wherein the oscillation frequency varying means is disposed in the non-rotating portion. The vacuum pump according to any one of claims 6 to 11, wherein the reference value signal varying means is disposed in the non-rotating portion. The vacuum pump according to any one of claims 8 to 12, wherein the difference signal amplification factor varying means is disposed in the non-rotating portion. The vacuum pump according to claim 1, further comprising a threshold setting unit configured to set a threshold for the temperature. The frequency characteristics of the modulated voltage, the frequency of the high frequency voltage, the modulated voltage, and the value of the measurement signal according to the inductance, capacitance, and resistance of the cable connecting the non-rotating portion and the control device The vacuum pump according to any one of claims 1 to 14, wherein the control device includes correction means for correcting at least one of the control unit. A rotating part having the conductor on the inner peripheral side or the lower end of the cylindrical part;
A non-rotating portion in which the sensor coil facing the conductor or a core of the sensor coil is disposed;
The vacuum pump according to any one of claims 1 to 15, further comprising a control device provided with the oscillator. 17. The vacuum pump according to claim 16, wherein an opposing surface of the conductor facing the sensor coil or the core of the sensor coil is perpendicular to a rotation center axis of the rotating part. The rotating part has at least one of a weight, a thick part, and a thin part at a position on a plane assumed to pass through the rotation center axis of the rotating part and the conductor. The vacuum pump according to claim 16 or 17. The vacuum pump according to any one of claims 16 to 18, wherein the conductor is arranged or formed on a target with respect to a rotation center axis of the rotating part. The vacuum pump according to any one of claims 16 to 19, wherein at least one of the conductor and the weight is sealed by a sealing means. The vacuum pump according to any one of claims 18 to 20, wherein at least one of the conductor and the weight is fixed to the rotating portion with a thermosetting adhesive.

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