Vacuum pump and electromagnetic unit for a vacuum pump

Abstract

Provided are an electromagnet unit that can suppress the influence of noise on a displacement sensor and can be set in a space-saving manner, and a vacuum pump including the electromagnet unit. The electromagnet unit (50) includes: a radial electromagnet (51) that controls a shaft (21) at a predetermined position; a radial sensor (53) that detects the position of the shaft (21); and a printed circuit board (55) that is interposed between the radial electromagnet (51) and the radial sensor (53), and is provided with a sensor wiring pattern (56) that connects coils (53c) of two mutually corresponding radial sensors (53, 53) to each other, and an electromagnet wiring pattern (57) that connects coils (51c) of two corresponding radial electromagnets (51, 51) to each other. The sensor wiring pattern (56) and the electromagnet wiring pattern (57) are arranged so as not to overlap when viewed from the axial direction (A).

Description

Technical Field

[0001] The present invention relates to a vacuum pump and an electromagnet unit for a vacuum pump. Background Art

[0002] In the manufacture of semiconductor devices such as memories and integrated circuits, in order to avoid the influence of dust in the air, etc., the processes of forming insulating films, metal films, semiconductor films, etc. and the processes of etching are carried out in a process chamber in a high vacuum state. For exhausting the process chamber, a vacuum pump such as a turbomolecular pump is used.

[0003] As such a vacuum pump, the following vacuum pump is known: in a housing having a suction port for sucking gas from the outside and an exhaust port for exhausting the sucked gas to the outside, a turbomolecular mechanism is arranged, and the turbomolecular mechanism has blades and fixed wings arranged in multiple stages alternately in the axial direction.

[0004] In addition, the vacuum pump has an electromagnet unit that controls the position of a rotating shaft based on the displacement of the rotating shaft provided with blades detected by various sensors. The electromagnet unit is such that if a displacement sensor that detects the displacement of the rotating shaft is disturbed by external noise, the displacement detection of the rotating shaft cannot be performed normally.

[0005] Therefore, in order to reduce such noise, the noise generation source and the displacement sensor are separately arranged or a shield disclosed in Patent Document 1 is provided. The shield is sandwiched between at least one of a radial electromagnet and a radial displacement sensor, and a high-frequency motor and a radial displacement sensor, and blocks the magnetic field and electric field of the radial electromagnet or the high-frequency motor related to the radial sensor.

[0006] Patent Document 1: Japanese Utility Model Laid-Open No. 4-14815.

[0007] Problems to be Solved by the Invention

[0008] However, when the noise generation source and the displacement sensor are separately arranged, it is necessary to ensure a separation distance that is not easily affected by noise with a margin in consideration of variations in assembly accuracy.

[0009] In addition, in a vacuum pump having the above shield, there is a problem that the vacuum pump is enlarged in the axial direction corresponding to the shield that blocks the magnetic field and electric field of the radial electromagnet or the high-frequency motor. Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] Therefore, a technical problem of suppressing the influence of noise on the displacement sensor and arranging the electromagnet unit in a space-saving manner has arisen, and an object of the present invention is to solve this problem.

[0012] Means for Solving the Problem

[0013] In order to achieve the above object, the vacuum pump according to the present invention is a vacuum pump having an electromagnet unit for controlling the position of a rotating shaft, and the electromagnet unit includes: a displacement sensor for detecting the position of the rotating shaft; an electromagnet for controlling the rotating shaft at a predetermined position; and a printed circuit board interposed between the displacement sensor and the electromagnet, provided with a sensor wiring pattern for connecting the coils of two corresponding displacement sensors to each other and an electromagnet wiring pattern for connecting the coils of two corresponding electromagnets to each other, and the sensor wiring pattern and the electromagnet wiring pattern are arranged so as not to overlap when viewed from the axial direction of the rotating shaft.

[0014] According to this configuration, the sensor wiring pattern and the electromagnet wiring pattern are separated, so that electromagnetic noise generated by the electromagnet can be suppressed from interfering with the displacement sensor, and false detection and malfunction of the displacement sensor caused by electromagnetic noise can be prevented.

[0015] In addition, in the vacuum pump according to the present invention, it is preferable that the sensor wiring pattern is arranged on one side of the printed circuit board, and the electromagnet wiring pattern is arranged on the other side of the printed circuit board.

[0016] According to this configuration, the sensor wiring pattern and the electromagnet wiring pattern are separated in the axial direction, so that electromagnetic noise generated by the electromagnet can be suppressed from interfering with the displacement sensor, and false detection and malfunction of the displacement sensor caused by electromagnetic noise can be prevented.

[0017] In addition, in the vacuum pump according to the present invention, it is preferable that the electromagnet wiring pattern is arranged outside the sensor wiring pattern in the radial direction of the rotating shaft.

[0018] According to this configuration, the sensor wiring pattern and the electromagnet wiring pattern are separated in the radial direction, so that electromagnetic noise generated by the electromagnet can be suppressed from interfering with the displacement sensor, and false detection and malfunction of the displacement sensor caused by electromagnetic noise can be prevented.

[0019] In addition, in the vacuum pump according to the present invention, it is preferable that the joint for welding and connecting the coil of the electromagnet and the electromagnet wiring pattern is arranged so as not to overlap with the core of the displacement sensor when viewed from the axial direction.

[0020] According to this configuration, the situation where electromagnetic noise generated by the electromagnet interferes with the displacement sensor via the joint can be suppressed.

[0021] In addition, in the vacuum pump of the present invention, it is preferable that the wire connecting the aforementioned sensor wiring pattern or the aforementioned electromagnet wiring pattern to an external device extends in the aforementioned axial direction so as not to overlap with the electromagnetic steel plate of the aforementioned electromagnet and the sensor steel plate of the aforementioned displacement sensor when viewed from the aforementioned axial direction.

[0022] According to this configuration, since the wire does not overlap with the electromagnetic steel plate of the electromagnet and the sensor steel plate of the displacement sensor when viewed from the axial direction, it is possible to suppress interference with the displacement sensor caused by electromagnetic noise generated by the wire.

[0023] In addition, in the vacuum pump of the present invention, it is preferable that the adjacent magnetic poles between the electromagnets adjacent in the circumferential direction of the aforementioned electromagnet are set to the same pole.

[0024] According to this configuration, the magnetic fluxes generated from the adjacent magnetic poles between the electromagnets adjacent in the circumferential direction of the electromagnet cancel each other out, so that the magnetic flux of the electromagnet can be reduced between the electromagnets adjacent in the circumferential direction.

[0025] In addition, in order to achieve the above object, the electromagnet unit of the present invention is an electromagnet unit that controls the position of the rotating shaft of the vacuum pump, and includes: a displacement sensor that detects the position of the aforementioned rotating shaft; an electromagnet that controls the aforementioned rotating shaft at a predetermined position; a printed circuit board that is sandwiched between the aforementioned displacement sensor and the aforementioned electromagnet and is provided with a sensor wiring pattern that connects the coils of the corresponding two aforementioned displacement sensors to each other and an electromagnet wiring pattern that connects the coils of the corresponding two aforementioned electromagnets to each other, and the aforementioned sensor wiring pattern and the aforementioned electromagnet wiring pattern are arranged so as not to overlap when viewed from the axial direction of the aforementioned rotating shaft.

[0026] According to this configuration, the sensor wiring pattern and the electromagnet wiring pattern are separated, whereby it is possible to suppress interference with the displacement sensor caused by electromagnetic noise generated by the electromagnet, and prevent misdetection and defects of the displacement sensor caused by electromagnetic noise.

[0027] Effects of the Invention

[0028] According to the present invention, by separating the sensor wiring pattern and the electromagnet wiring pattern, it is possible to suppress interference with the displacement sensor caused by electromagnetic noise generated by the electromagnet, and prevent misdetection and defects of the displacement sensor caused by electromagnetic noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a longitudinal sectional view of a vacuum pump according to an embodiment of the present invention.

[0030] Figure 2 is a side view showing the electromagnet unit.

[0031] Figure 3It shows a top view of a printed circuit board.

[0032] Figure 4 It shows a partial cut-away bottom view of a radial sensor.

[0033] Figure 5 It shows a side view of the electromagnet unit as viewed from arrow B of Figure 3 ...

[0034] Figure 6 It shows a bottom view of a printed circuit board.

[0035] Description of Reference Numerals

[0036] 1... Vacuum pump

[0037] 10... Housing

[0038] 11... Base

[0039] 12... Bolt

[0040] 13... Cylindrical part

[0041] 14... Exhaust port

[0042] 15... Suction port

[0043] 15a... Flange

[0044] 16... Suction port

[0045] 20... Rotor

[0046] 21... Shaft (rotating shaft)

[0047] 22... Blade

[0048] 23... Ground bearing

[0049] 24... Hub hole

[0050] 25... Bolt

[0051] 26... Rotor flange

[0052] 27... Shaft flange

[0053] 28... Rotating body

[0054] 28a... Outer peripheral surface

[0055] 29... Rotating wing

[0056] 30... Motor

[0057] 31... Rotating part

[0058] 32... Fixed part

[0059] 40……Stator column

[0060] 41……Bolt

[0061] 50……Electromagnet unit

[0062] 51, 51X, 51Y……Radial electromagnet

[0063] 51a……Electromagnetic steel plate

[0064] 51b……(Convex part of the electromagnetic steel plate)

[0065] 51c……(Coil of the radial electromagnet)

[0066] 51d……(Magnetic pole of the radial electromagnet)

[0067] 52……Axial electromagnet

[0068] 53, 53x, 53y……Radial sensor

[0069] 53a……Sensor steel plate

[0070] 53b……(Claw part of the sensor steel plate)

[0071] 53c……(Coil of the radial sensor)

[0072] 53d……(Magnetic pole of the radial sensor)

[0073] 54……Axial sensor

[0074] 55……Printed circuit board

[0075] 55a……(Surface of the printed circuit board)

[0076] 55b……(Back surface of the printed circuit board)

[0077] 56……Wiring pattern for sensor

[0078] 57……Wiring pattern for electromagnet

[0079] 58……Joint point

[0080] 59……Wire

[0081] 60……Control unit

[0082] 70……Fixed wing

[0083] 71……Gasket

[0084] 80……Stator

[0085] 81……Threaded groove part

[0086] A... Axial direction (axial orientation)

[0087] R... Radial direction (radial orientation)

[0088] C... Circumferential direction (of the electromagnetic unit)

[0089] PA... Turbomolecular pump mechanism

[0090] PB... Threaded groove pump mechanism. Detailed implementation manners

[0091] Based on the drawings, the implementation manners of the present invention are described. In addition, hereinafter, when referring to the number of constituent elements, numerical values, amounts, ranges, etc., unless specifically shown or specifically limited to a specific number based on the principle, the specific number is not limited, and it may be more than or less than the specific number.

[0092] Furthermore, when referring to the shape, positional relationship of the constituent elements, etc., unless specifically shown or considered not to be the case based on the principle, it includes cases where the shape, etc. is substantially similar or analogous to the shape, etc.

[0093] In addition, in the drawings, sometimes a part of the feature is enlarged, etc. to make the feature easier to understand, and the dimensional ratios of the constituent elements are not necessarily the same as the actual ones. In addition, in the cross-sectional view, in order to make the cross-sectional structure of the constituent elements easier to understand, the hatching of a part of the constituent elements is sometimes omitted.

[0094] Figure 1 It is a longitudinal sectional view showing the vacuum pump 1. The vacuum pump 1 is a composite pump, including a turbomolecular pump mechanism PA and a threaded groove pump mechanism PB housed in a substantially cylindrical housing 10.

[0095] The vacuum pump 1 includes: a housing 10; a rotor 20 having a shaft 21 rotatably supported in the housing 10; a motor 30 for rotationally driving the shaft 21; and a stator column 40 for housing a part of the shaft 21 and the motor 30.

[0096] The housing 10 includes: a base 11; a cylindrical portion 13 fixed via bolts 12 in a state of being placed on the base 11.

[0097] An exhaust port 14 communicating with an auxiliary pump (not shown) is provided on the lower side of the base 11.

[0098] An intake port 15 connected to a vacuum container such as a chamber (not shown) is formed at the upper end of the cylindrical portion 13. In addition, a flange 15a connected to the vacuum container is formed on the outer periphery of the intake port 15.

[0099] The rotor 20 has a shaft 21 and blades 22 that are fixed to the upper part of the shaft 21 and arranged concentrically with respect to the axis of the shaft 21. The blades 22 are integrally joined to a rotating body 28 described later to form a substantially cylindrical rotating wing 29.

[0100] The shaft 21 is position-controlled by a radial electromagnet unit and an axial electromagnet unit and is supported non-contact. The radial electromagnet unit is the electromagnet unit 50, which includes a radial electromagnet 51, a radial sensor 53, and a printed circuit board 55. The axial electromagnet unit includes an axial electromagnet 52 and an axial sensor 54.

[0101] The radial electromagnet 51, the axial electromagnet 52, the radial sensor 53, and the axial sensor 54 are connected to a control unit 60 that controls various devices constituting the vacuum pump 1.

[0102] The control unit 60 controls the excitation currents of the radial electromagnet 51 and the axial electromagnet 52 based on the detection value of the radial sensor 53 that detects the displacement of the radial direction R of the shaft 21 and the detection value of the axial sensor 54 that detects the displacement of the axial direction A of the shaft 21, so as to support the shaft 21 in a state of floating at a predetermined position.

[0103] The upper and lower parts of the shaft 21 are inserted into the ground bearing 23. When the shaft 21 becomes uncontrollable, the shaft 21 rotating at high speed contacts the ground bearing 23 to prevent damage to the vacuum pump 1.

[0104] The shaft 21 is in a state where its upper part is inserted into the hub hole 24, and is integrally mounted on the rotating wing 29 by inserting a bolt 25 through the rotor flange 26 and thread-mounting it on the shaft flange 27.

[0105] The motor 30 includes a rotating member 31 mounted on the outer periphery of the shaft 21 and a fixed member 32 arranged so as to surround the rotating member 31. The fixed member 32 is connected to the control unit 60, and the rotation of the shaft 21 is controlled by the control unit 60.

[0106] The stator column 40 is in a state of being placed on the base 11, and the lower end portion of the stator column 40 is fixed to the base 11 via bolts 41.

[0107] Next, the turbomolecular pump mechanism PA disposed in the upper half of the vacuum pump 1 will be described.

[0108] The turbomolecular pump mechanism PA includes: blades 22; and fixed wings 70 arranged with a gap between the blades 22 in the axial direction A. The blades 22 and the fixed wings 70 are arranged alternately and multi-stage in the axial direction A. In this embodiment, 5 stages of blades 22 and 5 stages of fixed wings 70 are arranged.

[0109] The blade 22 is inclined at a predetermined angle and is integrally formed on the upper outer peripheral surface of the rotary wing 29. In addition, a plurality of blades 22 are radially provided around the axis of the rotor 20.

[0110] The fixed wing 70 is composed of blades inclined in the opposite direction to the blade 22, and is positioned by being clamped in the axial direction A by a gasket 71 laminated on the inner wall surface of the cylindrical portion 13. In addition, a plurality of fixed wings 70 are also radially provided around the axis of the rotor 20.

[0111] The above-described turbo molecular pump mechanism PA uses the rotation of the blade 22 to transfer the gas sucked from the suction port 15 and the suction port 16 from the upper side to the lower side in the axial direction A.

[0112] Next, the screw groove pump mechanism PB disposed in the substantially lower half of the vacuum pump 1 will be described.

[0113] The screw groove pump mechanism PB includes a rotating body 28 provided at the lower part of the rotor 20 and extending in the axial direction A, and a substantially cylindrical stator 80 disposed to surround the outer peripheral surface 28a of the rotating body 28.

[0114] The stator 80 is placed on the base 11. The stator 80 has a screw groove portion 81 formed on the inner peripheral surface.

[0115] The above-described screw groove pump mechanism PB compresses the gas transferred from the suction port 15 and the suction port 16 to the lower side in the axial direction A by means of the dragging effect brought about by the high-speed rotation of the rotating body 28, and transfers it to the exhaust port 14. Specifically, after the gas is transferred to the gap between the rotating body 28 and the stator 80, it is compressed in the screw groove portion 81 and transferred to the exhaust port 14.

[0116] Next, the configuration and operation of the electromagnet unit 50 will be described based on the drawings. Figure 2 It is a side view showing the electromagnet unit 50. Figure 3 It is a top view of the printed circuit board 55 in which the arrangement relationship of the radial sensor 53 is illustrated by a dotted line. Figure 4 It is a partially cut-away bottom view of the radial sensor 53 in which the arrangement relationship of the printed circuit board 55 is illustrated by a dotted line. Figure 5 It is shown from Figure 3 The side view of the electromagnet unit 50 observed from the arrow B.

[0117] In addition, in Figure 1 Two radial electromagnets 51 and two radial sensors 53 are provided separately in the axial direction A. Since these have the same structure, the structure of the radial electromagnet 51 and the radial sensor 53 arranged above the axial direction A will be described as an example, and the description of the structure of the radial electromagnet 51 and the radial sensor 53 arranged below the axial direction A will be omitted.

[0118] The radial electromagnet 51 non - contactingly supports the shaft 21 with magnetic force in the radial direction R. Each radial electromagnet 51 is separably arranged at intervals of 90 degrees in the circumferential direction C of the electromagnet unit 50 and is arranged on the X - axis or the Y - axis. In addition, in the present embodiment, when differentiating the radial electromagnets 51 according to the direction of the supported shaft 21, for the one non - contactingly supporting the shaft 21 in the X - axis direction, an X is marked at the end of the number as a reference symbol, and for the one non - contactingly supporting the shaft 21 in the Y - axis direction, a Y is marked at the end of the number as a reference symbol. When collectively referring to these, only the number is used as a reference symbol.

[0119] The radial electromagnet 51 includes a pair of magnetic poles 51d, 51d formed by winding a coil 51c around a convex portion 51b of an electromagnetic steel plate 51a serving as a core portion. The pair of magnetic poles 51d, 51d have different polarities by winding the coil 51c in opposite directions.

[0120] The adjacent magnetic poles 51d, 51d between the radially adjacent electromagnets 51X, 51Y in the circumferential direction C are set to have the same polarity. Thus, the magnetic fluxes generated from the adjacent magnetic poles 51d, 51d between the radially adjacent electromagnets 51 in the circumferential direction C cancel each other out. Therefore, between the radially adjacent electromagnets 51X, 51Y in the circumferential direction C, the magnetic flux of the radial electromagnet 51 can be reduced.

[0121] The radial sensor 53 detects the displacement of the shaft 21 in the radial direction R. The radial sensor 53 is a known displacement sensor, such as an inductive displacement sensor or the like. The radial sensor 53 includes a pair of magnetic poles 53d, 53d formed by winding a coil 53c around a claw portion 53b of a sensor steel plate 53a serving as a core portion.

[0122] When viewed from above, the radial sensor 53 is arranged between the pair of magnetic poles 53d, 53d. In addition, in the present embodiment, when differentiating the radial sensor 53 according to the displacement detection direction, for the one arranged on the X - axis, an x is marked at the end of the number as a reference symbol, and for the one arranged on the Y - axis, a y is marked at the end of the number as a reference symbol. When collectively referring to these, only the number is used as a reference symbol.

[0123] The radial electromagnet 51 and the radial sensor 53 are arranged on opposite sides of each other with the printed circuit board 55 interposed therebetween in the axial direction A. Figure 6 It is a bottom view showing the printed circuit board 55.

[0124] On the printed circuit board 55, a sensor wiring pattern 56 connecting the coil 53c of the radial sensor 53 and an electromagnet wiring pattern 57 connecting the coil 51c of the radial electromagnet 51 are provided.

[0125] The wiring pattern 56 for the sensor and the wiring pattern 57 for the electromagnet are arranged so as not to overlap when viewed from the axial direction A. Thus, the wiring pattern 56 for the sensor and the wiring pattern 57 for the electromagnet are separated in the axial direction A, so that electromagnetic noise generated by the radial electromagnet 51 can be suppressed from interfering with the radial sensor 53. In addition, as long as the electromagnetic noise generated by the radial electromagnet 51 does not interfere with the radial sensor 53, the wiring pattern 56 for the sensor and the wiring pattern 57 for the electromagnet may also be arranged so that a part thereof overlaps when viewed from the axial direction A.

[0126] Specifically, the wiring pattern 56 for the sensor is provided on the surface 55a of the printed circuit board 55. The wiring pattern 56 for the sensor connects the coils 53c of the radially opposed radial sensors 53x to each other, or the coils 53c of the radially opposed radial sensors 53y to each other.

[0127] In addition, the wiring pattern 57 for the electromagnet is provided on the back surface 55b of the printed circuit board 55. The wiring pattern 57 for the electromagnet connects the coils 51c of the radially opposed radial electromagnets 51X to each other, or the coils 51c of the radially opposed radial electromagnets 51Y to each other.

[0128] Moreover, the wiring pattern 56 for the sensor is arranged closer to the inner side in the radial direction R than the wiring pattern 57 for the electromagnet when viewed from the axial direction A. Thus, the wiring pattern 56 for the sensor and the wiring pattern 57 for the electromagnet are separated in the radial direction R, so that electromagnetic noise generated by the radial electromagnet 51 can be suppressed from interfering with the radial sensor 53.

[0129] In addition, in the printed circuit board 55, the joint 58 where the coil 51c of the radial electromagnet 51 and the wiring pattern 57 for the electromagnet are welded and connected is arranged so as not to overlap with the sensor steel plate 53a of the radial sensor 53 when viewed along the axial direction A. Thus, electromagnetic noise generated by the radial electromagnet 51 can be suppressed from interfering with the radial sensor 53 via the joint 58. In addition, as long as the electromagnetic noise generated by the radial electromagnet 51 does not interfere with the radial sensor 53 via the joint 58, the joint 58 may also be arranged so that a part thereof overlaps with the sensor electromagnetic steel plate 53a of the radial sensor 53 when viewed along the axial direction A. In addition, the joint 58 is provided on the surface 55a of the printed circuit board 55 which is above the axial direction A, so that an operator can easily handle the joint 58 and welding can be performed smoothly.

[0130] In addition, a wire 59 that connects the wiring pattern 56 for the sensor or the wiring pattern 57 for the electromagnet to an external device extends in the axial direction A between the coils 51c of the radial electromagnets 51 adjacent to each other in the circumferential direction C. Thus, when viewed from the axial direction A, the wire 59 does not overlap with the electromagnetic steel plate 51a and the sensor steel plate 53a, so that electromagnetic noise generated by the wire 59 can be prevented from interfering with the radial sensor 53. With such wiring, the wire 59 can be led out to the outer peripheral side of the electromagnet 50 without unnatural bending. In addition, an increase in the size of the vacuum pump 1 in the axial direction A due to the lead-out of the wire can be prevented. Further, as long as the electromagnetic noise generated by the wire 59 does not interfere with the radial sensor 53, the wire 59 may be arranged so as to overlap a part of the electromagnetic steel plate 51a or a part of the sensor steel plate 53a when viewed from the axial direction A. [[ID=,2]]

[0131] In addition, the wiring pattern 56 for the sensor and the wiring pattern 57 for the electromagnet may be separately provided at a distance that can reduce the influence of electromagnetic noise, or may be collectively provided on one surface of the front surface 55a or the back surface 55b of the printed circuit board 55.

[0132] In this way, in the electromagnet unit 50 according to the present embodiment, by separating the wiring pattern 56 for the sensor and the wiring pattern 57 for the electromagnet in the axial direction A, electromagnetic noise generated by the radial electromagnet 51 can be prevented from interfering with the radial sensor 53, and malfunction or defect of the radial sensor 53 caused by electromagnetic noise can be prevented.

[0133] Moreover, in such an electromagnet unit 50, the radial sensors 53x arranged to face each other detect displacement in the X-axis direction above the detection axis 21, and send original displacement signals +xh and -xh corresponding to the displacement to the control unit 60.

[0134] In addition, the radial sensors 53y arranged to face each other detect displacement in the Y-axis direction of the detection axis 21 and send original displacement signals +yh and -yh corresponding to the displacement to the control unit 60.

[0135] In addition, the “+” in the reference sign of the original displacement signal indicates a signal detected by the radial sensors 53x and 53y arranged in the positive direction of the X-axis or Y-axis, and the “-” indicates a signal detected by the radial sensors 53x and 53y arranged in the negative direction of the X-axis or Y-axis.

[0136] Based on the displacement in the X-axis direction and the Y-axis direction of the axis 21, the control unit 60 generates electromagnetic drive signals +XH and -XH for driving the radial electromagnet 51X of the electromagnet unit 50, and controls the radial electromagnet 51X.

[0137] In addition, the control unit 60 generates electromagnetic drive signals +YH and -YH for driving the radial electromagnet 51Y of the electromagnet unit 50 to control the radial electromagnet 51Y.

[0138] In addition, the "+" in the reference symbol of the electromagnetic drive signal indicates a signal for controlling the radial electromagnet 51 arranged in the positive direction of the X-axis or Y-axis, and the "-" indicates a signal for controlling the radial electromagnet 51 arranged in the negative direction of the X-axis or Y-axis.

[0139] In addition, the present invention can be variously modified without departing from the gist of the present invention, and the present invention naturally includes such modifications.

Claims

1. A vacuum pump having an electromagnet unit for controlling the position of a rotating shaft, characterized in that the aforementioned electromagnet unit is provided with: a displacement sensor for detecting the position of the aforementioned rotating shaft; an electromagnet for controlling the aforementioned rotating shaft at a predetermined position; a printed circuit board sandwiched between the aforementioned displacement sensor and the aforementioned electromagnet, provided with a sensor wiring pattern connecting the coils of the corresponding two aforementioned displacement sensors to each other and an electromagnet wiring pattern connecting the coils of the corresponding two aforementioned electromagnets to each other, the aforementioned sensor wiring pattern and the aforementioned electromagnet wiring pattern are arranged so as not to overlap when viewed from the axial direction of the aforementioned rotating shaft, the aforementioned sensor wiring pattern is arranged on one side of the aforementioned printed circuit board, and the aforementioned electromagnet wiring pattern is arranged on the other side of the aforementioned printed circuit board.

2. The vacuum pump according to claim 1, characterized in that the aforementioned electromagnet wiring pattern is arranged outside the aforementioned sensor wiring pattern in the radial direction of the aforementioned rotating shaft.

3. The vacuum pump according to claim 1 or 2, characterized in that the joint connecting the coil of the aforementioned electromagnet and the aforementioned electromagnet wiring pattern by welding is arranged so as not to overlap with the core of the aforementioned displacement sensor when viewed from the aforementioned axial direction.

4. The vacuum pump according to claim 1 or 2, characterized in that the wire connecting the aforementioned sensor wiring pattern or the aforementioned electromagnet wiring pattern to an external device extends in the aforementioned axial direction so as not to overlap with the electromagnet steel plate of the aforementioned electromagnet and the sensor steel plate of the aforementioned displacement sensor when viewed from the aforementioned axial direction.

5. The vacuum pump according to claim 4, characterized in that the adjacent magnetic poles between the electromagnets adjacent in the circumferential direction of the aforementioned electromagnet are set to be of the same polarity.

6. An electromagnet unit for controlling the position of a rotating shaft of a vacuum pump, characterized in that it is provided with: a displacement sensor for detecting the position of the aforementioned rotating shaft; an electromagnet for controlling the aforementioned rotating shaft at a predetermined position; a printed circuit board sandwiched between the aforementioned displacement sensor and the aforementioned electromagnet, provided with a sensor wiring pattern connecting the coils of the corresponding two aforementioned displacement sensors to each other and an electromagnet wiring pattern connecting the coils of the corresponding two aforementioned electromagnets to each other, the aforementioned sensor wiring pattern and the aforementioned electromagnet wiring pattern are arranged so as not to overlap when viewed from the axial direction of the aforementioned rotating shaft, the aforementioned sensor wiring pattern is arranged on one side of the aforementioned printed circuit board, and the aforementioned electromagnet wiring pattern is arranged on the other side of the aforementioned printed circuit board.

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