JP3131428U - Vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum pump capable of accurately measuring the temperature of a rotating body in a turbo molecular pump or the like by a non-contact method.
A counterbore ZH is formed on the upper surface of a flange 3F integrated with a rotary shaft 3, and a through hole SH smaller in diameter than the counterbore ZH is formed in the center of the counterbore ZH. The magnetic material M is press-fitted into the stepped hole ZH and the through hole SH. This magnetic body M is not necessarily limited to the press-fitting attachment method, and may be attached by a bonding method using an adhesive. Corresponding to the attachment of the magnetic body M, a gap sensor GS for detecting the temperature of the rotating body is installed above the radial electromagnet. The temperature of the pump body 4 of the turbo molecular pump TP is measured in a non-contact manner by the gap sensor GS.
[Selection] Figure 1

Description

  The present invention relates to a vacuum pump typified by a turbo molecular pump or the like that houses a turbo mechanism in a casing and rotates it at a high speed to exhaust the room to a high vacuum.

  In this type of turbo molecular pump, the rotating body including the turbo mechanism is heated to a high temperature because the turbo mechanism is rotated at a high speed. When the temperature of the rotating body is increased, the rotating body itself is distorted, and the holding mechanism of the rotating body is also distorted, leading to a decrease in pump function. Therefore, this type of vacuum pump is required to measure and monitor the temperature of the inner rotating body and take measures. First, a description will be given according to FIG. 11 showing an example of a conventional turbo molecular pump TP.

  FIG. 11 shows a schematic configuration of the magnetic bearing type turbo molecular pump TP. In the figure, reference numeral 2 denotes a rotor which is an embodiment of a rotating body, which is a rotating frame body installed on the top of a rotating shaft, and includes a cylindrical body of a screw pump in a hybrid turbomolecular pump. Reference numeral 3 denotes a rotating shaft 3 to which a rotor 2 that is a rotating frame body on which a turbo mechanism described later is installed is supported in a non-contact manner by electromagnets 8, 9, and 10 provided in the pump body 4. The floating position of the rotating shaft 3 is detected by radial displacement sensors 5 and 6 and an axial displacement sensor 7 provided on the pump body 4. The electromagnets 8 and 9 constituting the radial magnetic bearing, the electromagnet 10 constituting the axial magnetic bearing, and the displacement sensors 5 to 7 constitute a five-axis control type magnetic bearing. In addition, 1 shows a pump casing and 15 shows a bearing.

  A circular disk 14 is provided at the lower end of the rotating shaft 3, and an electromagnet 10 is provided so as to sandwich the disk 14 vertically. By attracting the disk 14 by the electromagnet 10, the rotating shaft 3 floats in the axial direction. The disk 14 is fixed to the lower end portion of the rotating shaft 3 by a nut or the like (not shown) and rotates integrally with the rotating shaft 3.

  By the way, in the turbo molecular pump TP, the rotor 2 which is one mode of the rotating body is formed with a plurality of stages of rotating blades R along the rotation axis direction. Fixed wings S are arranged between the rotating wings R arranged vertically. The rotor blade R and the fixed blade S constitute a turbine mechanism of the turbo molecular pump TP. Each fixed wing S is held by a spacer P so as to be sandwiched up and down. The spacer P has a function of maintaining the gap between the fixed wings S at a predetermined interval as well as the holding function of the fixed wings S.

  Further, a screw stator NS that constitutes a drag pump (screw groove pump) NP is provided at a subsequent stage (downward in the figure) of the fixed blade S, and between the inner peripheral surface of the screw stator NS and the cylindrical body ET of the rotor 2. A gap is formed. The fixed wing S held by the rotor 2 and the spacer P is stored in the casing 1 in which the air inlet 11 is formed. When the rotating shaft 3 to which the rotor 2 is attached is rotationally driven by the motor 13 while being supported in a non-contact manner by the electromagnets 8 to 10, the gas on the intake port 11 side is exhausted through the space SP on the back pressure side as indicated by the arrow G. The gas exhausted to the back pressure side is exhausted by an auxiliary pump connected to the exhaust port 12.

  The turbo molecular pump TP is driven and controlled by the controller C. The controller C outputs a magnetic bearing drive control unit 1M for driving and controlling the magnetic bearing, a motor drive control unit 1C for driving and controlling the motor 13, and a detection unit 1S for detecting a gap between the magnetic bearings and an alarm such as a temperature abnormality. An alarm unit 1K is provided.

  Such a turbo molecular pump TP is an organic combination of the turbo pump function by the turbo mechanism TK and the thread groove pump function by the thread groove pump NP, and is usually called a hybrid turbo molecular pump. The thread groove pump NP is configured by a combination of a thread stator NS having a thread groove formed on an inner peripheral surface and a cylindrical body ET. As the turbo molecular pump TP, such a hybrid type has good exhaust characteristics and is often used. Thus, the rotor 2 provided with the exhaust mechanism is integrated with the rotary shaft 3 and is rotationally driven by the motor 13 while being supported by the electromagnets 8 to 10 in a non-contact manner. For this purpose, a method of measuring a rotating body such as an inner turbo mechanism TK in a non-contact manner is used (see Patent Document 1).

In the above configuration, the non-contact temperature measuring method described above is equipped with a ferromagnetic material whose permeability changes in the temperature range to be measured in the rotating body, and the ferromagnetic material fixed on the magnetic body and the fixed body side. A magnetic circuit is constituted by members made of body material, and means for measuring the magnetic resistance of the magnetic circuit is provided.
This non-contact temperature measuring device utilizes a well-known relationship that exists between a certain physical property and temperature. That is, for a rotating body that rotates at high speed in a vacuum, a ferromagnetic material having a Curie point in the temperature range to be measured is used. This type of material loses its ferromagnetism at high temperatures and changes to a paramagnetic material. As a result, of the magnetic flux in the magnetic circuit, the magnetic flux contributed by the material is remarkably reduced and the magnetic resistance is increased. By this principle, the temperature of the rotating body can be realized in a non-contact manner.

  When the non-contact type temperature measurement method based on the above-described principle is implemented inside the turbo molecular pump TP, it is implemented with the principle configuration shown in FIG. 8, for example. FIG. 8 is a diagram for explaining an inductance change of the rotating body and the gap sensor GS, and is a schematic diagram of a magnetic circuit generated by the gap sensor GS and the magnetic body M as a target. Specifically, the gap sensor GS is fixed on the stator side of the turbo molecular pump TP, specifically on the pump body 4 side. The structure is such that a coil is wound around a core having a high magnetic permeability such as a silicon steel plate. Is. A high frequency voltage having a constant frequency is applied as a carrier wave to the coil of the gap sensor GS, and a high frequency magnetic field is formed from the gap sensor GS toward the target magnetic body M. In addition, as shown in FIG. 11, the magnetic body M is attached to the recessed part 3K formed in the lower surface of the flange 3F in the flange 3F integral with the rotating shaft 3. As shown in FIG. This position is selected because the rotary shaft 3 has a temperature gradient, and therefore a position close to the rotor is preferable.

  On the other hand, a magnetic material having a Curie temperature substantially equal to or close to the allowable temperature of the rotor 2 is used for the magnetic material M as a target. Thus, it should be noted that the allowable temperature is the temperature of the rotor 2 and is a member on which the magnetic body M is installed, that is, the flange 3F in the illustrated example, but does not necessarily coincide with the flange 3F. As shown in FIG. 11, when the rotor 2 is installed on the flange 3F, the flange 3F is made of steel or the like and is made of a material different from that of the rotor 2 made of aluminum, considering the thermal conductivity between the two. Setting is required. In the case of aluminum, the temperature is about 120 ° C to 140 ° C. Examples of the magnetic material having a Curie temperature of about 130 ° C. include nickel / zinc ferrite and manganese / zinc ferrite.

When the temperature of the magnetic body M, which is the target, rises due to the temperature rise of the flange 3F and exceeds the Curie temperature, the magnetic permeability of the magnetic body M, which is the target, rapidly decreases to about the vacuum permeability. When the magnetic permeability of the target magnetic body M changes in the magnetic field formed by the gap sensor GS, the inductance of the gap sensor GS changes.
As a result, a signal change corresponding to a change in magnetic permeability can be detected by detecting and rectifying the amplitude-modulated signal output from the gap sensor GS given a carrier wave. In this way, the temperature can be detected in a non-contact manner.

  Incidentally, as shown in FIG. 11, the rotor 2 is crowned by a flange 3 </ b> F formed above the rotating shaft 3, and a non-contact type temperature measuring mechanism is installed in the rotor 2. In this case, the magnetic body M is originally embedded in a part of the rotor 2, but the rotor 2 is in close contact with the flange 3 </ b> F so that the temperature is equal and the measurement is facilitated. Or the method of embedding the magnetic body M in the flange 3F and measuring is adopted.

JP 2006-194094 A

  However, in order to provide a non-through hole in the rotary shaft 3 from the direction opposite to the fastening surface of the rotary shaft 3 and the flange 3F, a special jig, a long cutting tool, etc. are required because the rotary shaft 3 exists. However, there is a problem that it takes cost to obtain dimensional accuracy. Also, if the dimensional accuracy is poor, the temperature cannot be measured accurately due to the contact between the magnetic material and the sensor or the decrease in sensing sensitivity. The present invention provides a vacuum pump that solves such problems.

In order to solve the above-mentioned problems, the turbo molecular pump provided by the present invention is provided with a magnetic body in a part of a rotating body, and at a fixing part of the pump body for detecting a temperature change of the magnetic body. An inductance type gap sensor that detects a change in magnetic permeability due to the temperature of the magnetic body as an inductance change is disposed at a portion facing the magnetic body, and a vacuum pump that houses a rotor that performs an exhaust function. The magnetic body is provided in a through hole having a large-diameter step on the rotating body side opposite to the installation side. Therefore, the through hole is a counterbore and the magnetic material is reliably installed.
In order to solve the above-mentioned problem, the turbo molecular pump provided by the present invention secondly has a through hole having a step in which the surface on the side facing the lower surface of the rotor becomes larger in the flange of the rotating shaft, The installation of the magnetic body in the through hole is fixed by adhesion or press fitting. Therefore, the magnetic body is more firmly installed in the through hole by a simple means.
Furthermore, in order to solve the above-described problems, the turbo molecular pump provided by the present invention fifthly has a magnetic body installed through a shim with respect to a through hole having a step, and the magnetic body is disposed in the axial direction of the rotating body. The position is adjustable. Therefore, more accurate temperature measurement is possible.
Further, in order to solve the above problems, the turbo molecular pump provided by the present invention in the sixth aspect is such that the magnetic body is made of the same material as the flange formed integrally with the rotating shaft, the disk-shaped body coupled to the rotating body, or the rotor. It is attached to the attachment member formed in (1), and is installed in the through hole via this attachment member. Therefore, accurate temperature measurement is possible with a simpler structure.
Furthermore, in order to solve the above-described problems, the turbo molecular pump provided by the present invention seventhly has a magnetic body attached to an attachment member formed of the same material as the flange of the rotating shaft, and passes through the attachment member. It is the one installed in the hole. Therefore, accurate temperature measurement is possible with a simpler structure.
Furthermore, in order to solve the above problems, the turbo molecular pump provided by the present invention in the eighth aspect is that the mounting member is installed in the through hole via the shim. Therefore, the position adjustment of the magnetic material can be simplified and accurate temperature measurement is possible.
Furthermore, in order to solve the above-described problems, the turbo molecular pump provided by the present invention in the ninth aspect is such that the magnetic body is joined to the mounting member by press-fitting or an adhesive, and the magnetic body is firmly attached. Enables accurate temperature measurement.

  It is possible to measure the temperature of a rotating body of a turbo molecular pump that rotates at high speed in a non-contact manner, and to provide an inexpensive and highly reliable vacuum pump.

  The feature of the present invention is that the temperature of the rotating body in the turbo molecular pump is measured in a non-contact manner. However, the best mode of the present invention is best applied to a hybrid turbo molecular pump even if it is a turbo molecular pump. It is.

By the way, the present invention is related to the temperature measurement of this rotating body, but the present invention gives the following three examples for specific embodiments of the rotating body that is the object of temperature measurement.
The first is a “rotating shaft”. More specifically, the flange is formed integrally with the rotating shaft. This flange is generally provided at the top of the rotating shaft.
The second is a “rotor”. This rotor is a rotating frame that is installed above the rotation shaft, and a turbo mechanism is installed. In the case of a hybrid turbo molecular pump, a cylindrical body that constitutes a screw pump is also included in this “rotor” as shown in the illustrated example. included.
The third is “a disk-like body coupled to a rotating shaft”. In other words, it is a disk-shaped part that is coupled or joined to the top of the rotating shaft. As a method of coupling or joining, there are a method of coupling a rotating shaft and a disk-like body with a screw, a method of forming an uneven portion on a joint surface of each other, a method of combining the unevenness, and fitting.
These “rotating shaft”, “rotor”, and “disc-like body coupled to the rotating shaft” specified in the claims of the utility model registration shall be interpreted as described above.

A first embodiment provided by the present invention is as shown in FIG. 1 have the same functions as those in FIG. 11, and detailed descriptions thereof are omitted.
As shown in FIG. 1, a counterbore ZH is drilled in the upper surface of the flange 3F integrated with the rotary shaft 3, and a through hole SH smaller in diameter than the counterbore ZH is drilled in the center of the counterbore ZH. Yes. That is, the magnetic body M is installed in the counterbore ZH and the through hole SH in which the step 3D is formed.

  Various types of installation methods can be considered for the installation of the magnetic body M, and installation using a mechanical method or a bonding method using an adhesive may be used. Corresponding to the installation of the magnetic body M, a gap sensor GS for detecting the temperature of the rotating body is installed above the radial electromagnet. The temperature of the pump body 4 of the turbo molecular pump TP is measured in a non-contact manner by the gap sensor GS. Reference numeral 16 denotes a mounting member for the magnetic body M.

A second embodiment provided by the present invention is shown in FIG. In FIG. 2, a through hole SH having a step 3 </ b> D is formed in the flange 3 </ b> F of the rotating shaft 3, and a magnetic body M is attached to the through hole SH via an attachment member 17. The fitting of the mounting member 17 to the step 3D is performed by press fitting or bonding with an adhesive. In addition, about the method of installation of the magnetic body M to this attachment member 18, there also exists a method as shown in FIG. 3, FIG. In this example, a plurality of magnetic bodies M are installed on one mounting member 18, but FIG. 3 is an example in which each magnetic body M is bonded to the mounting member 18, and FIG. This is an example in which a fitting hole KH that is not shaped is formed, and a magnetic body M is press-fitted and joined to each fitting hole KH. The fitting hole KH may be a through-type. In this embodiment, the flange 3F is not limited to be made of the same material as the rotor 2. That is, specifically, the rotating shaft 3 includes a case of a material different from that of the rotor 2. Further, the thickness of the mounting member 17 does not have to be the same as the depth of the counterbore hole ZH, and may be smaller than the depth of the counterbore hole ZH, that is, may be thinner. In this case, it is advantageous for thickness adjustment.
The same can be said for the embodiment shown in FIG.

A third embodiment provided by the present invention is as shown in FIG. The feature of the present embodiment is that the magnetic body M is attached to a member formed of the same material as the rotating shaft 3. That is, as shown in FIG. 5, a counterbore ZH is formed in the flange 3 </ b> R made of the same material integrally with the rotary shaft 3, and the magnetic body M fixed to the attachment member 20 is attached to the through-hole SH. Yes.
In this embodiment, a through hole SH having a step 3D is formed in the flange 3R. However, the magnetic body M is fixed to the mounting member 20, and the mounting member 20 is fixed to the step 3D.
Furthermore, the present invention provides an embodiment in which a shim 22 is interposed between the mounting member 21 and the step 3D as shown in FIG. According to this embodiment, the position of the magnetic body M can be adjusted in the amount of protrusion from the lower surface of the flange 3R, that is, in the axial direction of the rotating body. In the case of the embodiment shown in FIG. 6, the material of the shim 22 may be the same material as the flange 3R.

A fourth embodiment provided by the present invention is as shown in FIG. FIG. 7 is a diagram showing only the upper direction of the vacuum pump shown in FIG. 1, and components denoted by the same reference numerals as those in FIG. 1 in FIG. 7 have the same functions as those in FIG.
In this embodiment, the magnetic body M is attached to the rotor 2 and the temperature is measured. A through hole 3H is formed in the flange 3F integrated with the rotary shaft 3, and a through hole 2H is formed in the rotor 2 above the through hole 3H. The magnetic body M is formed in the through hole 2H. The mounting member 23 on which is installed is held. The magnetic body M and the gap sensor GS are opposed to each other through the through holes 2H and 3H, and temperature measurement is possible.

  A fifth embodiment provided by the present invention is shown in FIG. FIG. 9 is a diagram showing only the rotor 2 and the pump body 4 in the turbo molecular pump TP. In this embodiment, a magnetic body M is embedded between the rotor 2 and the flange 3F integrated with the rotary shaft 3, and a gap sensor GS is disposed on the top of the pump body 4 on the fixed side. Therefore, temperature measurement is performed by detecting the magnetic body M by the gap sensor GS. The magnetic body M is embedded in a through hole 2H formed in the rotor 2 and a through hole 3P formed in the flange 3F.

A sixth embodiment provided by the present invention is shown in FIG. In the sixth embodiment, the magnetic body M is directly disposed on the flange 3F integrated with the rotary shaft 3. The magnetic body M has a shape in which the disk of the head and the head of the support are integrated, and the position of the magnetic body M can be adjusted in the axial direction of the rotating body through the shim 24.
The vacuum pump provided by the present invention is as described above, but is not limited to the structure and shape shown in the above and illustrated examples, and includes various modifications. For example, in the illustrated example, an example of a turbo-molecular pump is given as the vacuum pump, but the present invention can also be applied to other pumps that exhibit a pump function by rotational driving of a rotating body. Further, even in the case of a turbo molecular pump, the invention is not limited to the hybrid type turbo molecular pump as shown in the figure, and the present invention can be applied to a turbo molecular pump having only a turbo mechanism.

It is a figure which shows the structure of the whole vacuum pump which shows 1st Example by this invention. It is a figure which shows the Example by this invention concretely. It is a figure which shows the other example of the 2nd Example by this invention. It is a figure which shows the other example of the 2nd Example by this invention. It is a figure which shows the structure of the 3rd Example by this invention. It is a figure which shows the other example of the 3rd Example by this invention. It is a figure which shows the 4th Example by this invention. It is a figure which shows the principle of the temperature measurement by a non-contact system. It is a figure which shows the 5th Example by this invention. It is a figure which shows the 6th Example by this invention. It is a figure which shows the conventional structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pump casing 2 Rotor 2D Step 2H Through-hole 3 Rotary shaft 3D Step 3F Flange 3H Through-hole 3K Recess 3P Through-hole 3R Flange 4 Pump main body 5 Displacement sensor 6 Displacement sensor 7 Displacement sensor 8 Electromagnet 9 Electromagnet 10 Electromagnet 11 Inlet 12 Exhaust Port 13 Motor 14 Disk 15 Bearing 16 Mounting member 17 Mounting member 18 Mounting member 19 Mounting member 20 Mounting member 21 Mounting member 22 Shim 23 Mounting member 24 Shim C Controller 1K Alarm unit 1S Detection unit 1C Motor drive control unit 1M Magnetic bearing drive control Part ET Cylindrical body G Arrow GS Gap sensor KH Mating hole M Magnetic body NP Screw groove pump NS Screw stator P Spacer R Rotating blade S Fixed blade SH Through hole SP Space TK Turbo mechanism TP Turbo molecular pump ZH Counterbore

Claims (9)

  An output of a motor is transmitted through a rotating shaft, and is a vacuum pump that houses a rotating body that performs an exhaust function by being rotationally driven. The magnetic body is installed in the rotating body, and the magnetic body In order to detect the temperature of the vacuum pump, an inductance type gap sensor that detects a change in permeability due to the temperature of the magnetic body as an inductance change at a portion facing the magnetic body at the fixed portion of the pump body is an inductance type. A vacuum pump characterized in that the magnetic body is disposed in a through hole having a large-diameter step on the rotating body side opposite to the gap sensor installation side.   2. The vacuum pump according to claim 1, wherein the through hole is formed in a flange formed integrally with the rotary shaft.   2. The vacuum pump according to claim 1, wherein the through hole is formed in a disk-like body coupled to the rotating shaft.   2. The vacuum pump according to claim 1, wherein the through-hole is formed above the rotating shaft and is formed in a rotor provided with a turbo mechanism or the like.   5. The magnetic body is installed through a shim with respect to a through hole having a step, and the magnetic body is configured to be positionally adjustable in the axial direction of the rotating body. Vacuum pump.   The magnetic body is attached to a flange formed integrally with the rotating shaft, a disk-shaped body coupled to the rotating body, or a mounting member made of the same material as the rotor, and a through hole having a step is formed through the mounting member. The vacuum pump according to claim 1, wherein the vacuum pump is installed.   3. The vacuum pump according to claim 2, wherein the magnetic body is attached to an attachment member made of the same material as the flange of the rotary shaft, and is installed in the through hole through the attachment member.   8. The magnetic material according to claim 6, wherein the magnetic material is installed in a through hole having a step through a shim so that the magnetic material can be adjusted in the axial direction of the rotating body. Vacuum pump.   The magnetic body is bonded or press-fitted to a through-hole having a step with a flange formed integrally with the rotating shaft, a disk-like body coupled to the rotating body, or an attachment member made of the same material as the rotor. 9. The vacuum pump according to claim 6, wherein the vacuum pump is provided.

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