Method for manufacturing vacuum pump, vacuum pump, and stator for vacuum pump

Abstract

Provided are a method for manufacturing a vacuum pump, a vacuum pump, and a stator for the vacuum pump, which can improve the exhaust performance of the vacuum pump. A method for manufacturing a vacuum pump, wherein a metal plate is subjected to cutting and bending processing to integrally form a stator (41), wherein the stator (41) has an outer peripheral edge (45) located at an outer peripheral side end, an inner peripheral edge (44) located at an inner peripheral side end, and a stator wing (43) located between the outer peripheral edge (45) and the inner peripheral edge (44). The inclination angle (θ) of the stator wing (43) relative to the outer peripheral edge (45) is constant from the inner peripheral side end to the outer peripheral side end of the stator wing (43), the upstream side ridgeline (54) of the stator wing side end portion (53C) located at the upstream side of the stator wing (43) is a straight line from the inner peripheral side end to the outer peripheral side end of the stator wing (43), and the axial gap (S) relative to the surface (P1) of the downstream side end portion of the rotor wing (32) arranged to face the upstream side ridgeline (54) is constant.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a vacuum pump, a vacuum pump and a stator used for the vacuum pump. Background Art

[0002] Semiconductor manufacturing equipment, liquid crystal manufacturing equipment, electron microscopes, surface analysis equipment, or micro-processing equipment require that the environment inside the equipment is in a highly vacuum state. In order to make the interior of these equipment in a highly vacuum state, a vacuum pump is used. The vacuum pump can discharge gas to the outside by rotating the rotor blade relative to the stator blade, thereby maintaining a high vacuum inside the above-mentioned equipment.

[0003] For example, Patent Document 1 describes a method in which a plate-like disk is punched to form stator blades arranged in a circumferential direction, and the stator blades are formed by bending the stator blades to stand upright.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2006-348935.

[0005] In the method described in Patent Document 1, the length of the stator blades that rise in the axial direction (corresponding to the dimension T) is different between the inner circumference and the outer circumference of the stator blades. Therefore, the gap between the rotor blades and the stator blades arranged in the axial direction is different between the inner circumference and the outer circumference. When the gap between the rotor blades and the stator blades in the axial direction is large, gas backflow occurs between the rotor blades and the stator blades, which becomes a factor in the deterioration of exhaust performance. Summary of the invention

[0006] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a vacuum pump, a vacuum pump, and a stator for the vacuum pump, which can improve the exhaust performance of the vacuum pump.

[0007] One scheme of the manufacturing method of the vacuum pump of the present invention for achieving the above-mentioned object is a manufacturing method of a vacuum pump, wherein the vacuum pump comprises a first cover, a second cover, a rotor, a plurality of rotor wings, a stator, a driving unit, and a bearing, wherein the first cover has an air intake port, and the second cover has an air exhaust port, the rotor is arranged in a space sealed by at least the first cover and the second cover, and has a shaft, the plurality of rotor wings are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor, the stator is alternately arranged with the rotor wings in the axial direction of the shaft, the driving unit drives the shaft to rotate, and the bearing supports the shaft to be rotatable, and the manufacturing method of the vacuum pump is characterized in that it comprises the following steps: cutting a metal plate, thereby removing the metal plate located at the outer peripheral side end position of the stator The outer peripheral edge of the stator, the inner peripheral edge located at the inner peripheral end of the stator, and the stator wing located between the outer peripheral edge and the inner peripheral edge are formed integrally, and the stator wing side end portion, which is the end portion of the stator wing in the circumferential direction of the stator, is formed straightly from the inner peripheral end to the outer peripheral end of the stator wing; the metal plate is subjected to a bending process, thereby bending the stator wing so that the inclination angle of the stator wing relative to the outer peripheral edge is constant from the inner peripheral end to the outer peripheral end of the stator wing; it is configured so that the upstream side ridgeline of the stator wing side end portion located on the upstream side of the stator wing is a straight line from the inner peripheral end to the outer peripheral end of the stator wing, and the axial gap is constant relative to the surface of the downstream side end of the rotor wing arranged opposite to the upstream side ridgeline.

[0008] Another embodiment of the method for manufacturing a vacuum pump of the present invention for achieving the above-mentioned purpose is a method for manufacturing a vacuum pump, wherein the vacuum pump comprises a first cover, a second cover, a rotor, a plurality of rotor wings, a stator, a drive unit, and a bearing, wherein the first cover has an air intake port, and the second cover has an air exhaust port, the rotor is arranged in a space sealed by at least the first cover and the second cover, and has a shaft, the plurality of rotor wings are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor, the stator is alternately arranged with the rotor wings in the axial direction of the shaft, the drive unit drives the shaft to rotate, and the bearing supports the shaft to be rotatable, and the method for manufacturing the vacuum pump is characterized in that it comprises the following steps: cutting a metal plate, thereby cutting a metal plate located at an outer peripheral side end position of the stator The outer peripheral edge, the inner peripheral edge located at the inner peripheral end of the stator, and the stator wing located between the outer peripheral edge and the inner peripheral edge are formed integrally, and the stator wing side end portion, which is the end portion of the stator wing in the circumferential direction of the stator, is formed in a straight line or a curve from the inner peripheral end to the outer peripheral end of the stator wing; the metal plate is subjected to a bending process, thereby bending the stator wing so that the inclination angle of the stator wing relative to the outer peripheral edge changes from the inner peripheral end to the outer peripheral end of the stator wing; it is configured so that the upstream side ridgeline of the stator wing side end portion located on the upstream side of the stator wing is a curve from the inner peripheral end to the outer peripheral end of the stator wing, and the axial gap is constant relative to the surface of the downstream side end of the rotor wing arranged opposite to the upstream side ridgeline.

[0009] One embodiment of the vacuum pump of the present invention for achieving the above-mentioned object is a vacuum pump, wherein the vacuum pump comprises a first cover, a second cover, a rotor, a plurality of rotor blades, a stator, a drive unit, and a bearing, wherein the first cover has an air intake port, the second cover has an air exhaust port, the rotor is arranged in a space sealed by at least the first cover and the second cover, and has a shaft, the plurality of rotor blades are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor, the stator is alternately arranged with the rotor blades in the axial direction of the shaft, the drive unit drives the shaft to rotate, and the bearing supports the shaft to be rotatable, and the vacuum pump is characterized in that The stator comprises an outer peripheral edge located at the outer peripheral end of the stator, an inner peripheral edge located at the inner peripheral end of the stator, and a stator wing located between the outer peripheral edge and the inner peripheral edge, the outer peripheral edge, the inner peripheral edge and the stator wing being integrally formed of a metal plate, the inclination angle of the stator wing relative to the outer peripheral edge being constant from the inner peripheral end to the outer peripheral end of the stator wing, the upstream ridgeline of the stator wing side end portion located at the upstream side of the stator wing being a straight line from the inner peripheral end to the outer peripheral end of the stator wing, and the axial gap being constant relative to the surface of the downstream side end portion of the rotor wing arranged opposite to the upstream ridgeline.

[0010] Another embodiment of the vacuum pump of the present invention for achieving the above-mentioned purpose is a vacuum pump, wherein the vacuum pump comprises a first cover, a second cover, a rotor, a plurality of rotor wings, a stator, a driving unit, and a bearing, wherein the first cover has an air intake port, the second cover has an air exhaust port, the rotor is arranged in a space sealed by at least the first cover and the second cover, and has a shaft, the plurality of rotor wings are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor, the stator is alternately arranged with the rotor wings in the axial direction of the shaft, the driving unit drives the shaft to rotate, and the bearing supports the shaft to be rotatable, and the vacuum pump is characterized in that the front The stator comprises an outer peripheral edge located at the outer peripheral end of the stator, an inner peripheral edge located at the inner peripheral end of the stator, and a stator wing located between the outer peripheral edge and the inner peripheral edge, the outer peripheral edge, the inner peripheral edge and the stator wing are integrally formed of a metal plate, the inclination angle of the stator wing relative to the outer peripheral edge changes from the inner peripheral end to the outer peripheral end of the stator wing, the upstream ridgeline of the stator wing side end portion located at the upstream side of the stator wing is a curve from the inner peripheral end to the outer peripheral end of the stator wing, and the axial gap is constant relative to the surface of the downstream side end portion of the rotor wing arranged opposite to the upstream ridgeline.

[0011] One embodiment of a stator for a vacuum pump of the present invention for achieving the above-mentioned object is a stator, wherein the stator is used for a vacuum pump, wherein the vacuum pump comprises a first cover, a second cover, a rotor, a plurality of rotor wings, a stator, a driving unit, and a bearing, wherein the first cover has an air intake port, the second cover has an air exhaust port, the rotor is arranged in a space sealed by at least the first cover and the second cover, and has a shaft, the plurality of rotor wings are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor, the stator is alternately arranged with the rotor wings in the axial direction of the shaft, the driving unit drives the shaft to rotate, and the bearing supports the shaft to be rotatable, and the characteristics of the stator are as follows: The characteristic is that the stator has an outer peripheral edge located at the outer peripheral side end of the stator, an inner peripheral edge located at the inner peripheral side end of the stator, and a stator wing located between the outer peripheral edge and the inner peripheral edge; the outer peripheral edge, the inner peripheral edge and the stator wing are formed integrally by a metal plate; the inclination angle of the stator wing relative to the outer peripheral edge is constant from the inner peripheral side end to the outer peripheral side end of the stator wing; the upstream side ridgeline of the stator wing side end portion located on the upstream side of the stator wing is a straight line from the inner peripheral side end to the outer peripheral side end of the stator wing; and the axial gap is constant relative to the surface of the downstream side end portion of the rotor wing arranged opposite to the upstream side ridgeline.

[0012] Another embodiment of the stator for a vacuum pump of the present invention for achieving the above-mentioned object is a stator, wherein the stator is used for a vacuum pump, wherein the vacuum pump comprises a first cover, a second cover, a rotor, a plurality of rotor wings, a stator, a driving unit, and a bearing, wherein the first cover has an air intake port, the second cover has an air exhaust port, the rotor is arranged in a space sealed by at least the first cover and the second cover, and has a shaft, the plurality of rotor wings are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor, the stator is alternately arranged with the rotor wings in the axial direction of the shaft, the driving unit drives the shaft to rotate, the bearing supports the shaft to be rotatable, and the stator The characteristic is that the stator has an outer peripheral edge located at the outer peripheral side end of the stator, an inner peripheral edge located at the inner peripheral side end of the stator, and a stator wing located between the outer peripheral edge and the inner peripheral edge, the outer peripheral edge, the inner peripheral edge and the stator wing are formed integrally by a metal plate, the inclination angle of the stator wing relative to the outer peripheral edge changes from the inner peripheral side end to the outer peripheral side end of the stator wing, the upstream side ridgeline of the stator wing side end portion located on the upstream side of the stator wing is a curve from the inner peripheral side end to the outer peripheral side end of the stator wing, and the axial gap is constant relative to the surface of the downstream side end portion of the rotor wing arranged opposite to the upstream side ridgeline.

[0013] Effects of the Invention

[0014] The manufacturing method of the vacuum pump constructed as described above can arrange the upstream ridgeline of the stator blade with a constant gap with high dimensional accuracy relative to the surface where the downstream end of the rotor blade is arranged. Therefore, the backflow of gas can be suppressed and the exhaust performance of the vacuum pump can be improved.

[0015] The length or width of the slit hole formed in the metal plate by the cutting process may be at least 0.2 times the thickness of the metal plate. Thus, the die for forming the slit hole will not be too thin, and damage to the die can be suppressed.

[0016] The radius of curvature of the corners of the slit holes formed in the metal plate by the cutting process may be 0.2 mm or more. This can prevent stress from concentrating on the corners and causing damage to the stator.

[0017] The length of the slit hole formed in the metal plate by the cutting process in the circumferential direction of the stator can also be increased from the inner circumferential side end to the outer circumferential side end of the stator blade. As a result, it is easy to make the length of the stator blade in the circumferential direction of the stator constant from the inner circumferential side end to the outer circumferential side end of the stator blade. Therefore, by bending after the cutting process, the inclination angle of the stator blade relative to the outer peripheral edge can be made constant from the inner circumferential side end to the outer circumferential side end, and the upstream side ridgeline of the stator blade is arranged so that the surface gap relative to the downstream side end of the rotor blade is constant.

[0018] The length of the slit hole formed in the metal plate by the cutting process in the circumferential direction of the stator can also be equal from the inner circumferential side end to the outer circumferential side end of the stator wing. As a result, it is easy to increase the length of the stator wing in the circumferential direction of the stator from the inner circumferential side end to the outer circumferential side end of the stator wing. Therefore, by bending after the cutting process, the inclination angle of the stator wing relative to the outer peripheral edge can be changed from the inner circumferential side end to the outer circumferential side end, and the gap between the upstream side ridgeline of the stator wing and the downstream side end surface where the rotor wing is arranged is constant.

[0019] The circumferential length of the stator of the slit hole formed in the metal plate by the cutting process can also be reduced from the inner circumferential side end to the outer circumferential side end of the stator wing. As a result, it is easy to increase the circumferential length of the stator wing from the inner circumferential side end to the outer circumferential side end of the stator wing. Therefore, by bending after the cutting process, the inclination angle of the stator wing relative to the outer peripheral edge can be changed from the inner circumferential side end to the outer circumferential side end, and the upstream side ridgeline of the stator wing can be configured to have a constant gap relative to the downstream side end surface where the rotor wing is configured. In addition, the circumferential length of the slit hole changes, so the overall thinning of the mold for forming the slit hole can be suppressed, and the damage of the mold can be suppressed.

[0020] The length of the slit hole adjacent to the outer peripheral edge of the metal plate formed by the cutting process in the radial direction of the stator may be smaller than the length of the outer peripheral edge in the radial direction. Thus, in the cutting process for forming the slit hole, it is easy to secure a portion clamped by a mold on the radially outer side of the slit hole. Therefore, the slit hole can be appropriately formed on the stator in the cutting process.

[0021] The length of the slit hole adjacent to the inner peripheral edge of the metal plate formed by the cutting process in the radial direction of the stator may be smaller than the length of the inner peripheral edge in the radial direction. Thus, in the cutting process for forming the slit hole, it is easy to secure a portion clamped by a die at the radial inner side of the slit hole. Therefore, the slit hole can be appropriately formed on the stator in the cutting process.

[0022] The radial length of the stator of the outer connecting portion that connects the stator wing of the stator to the outer peripheral edge formed on the metal plate by the cutting process can also be smaller than the radial length of the outer peripheral edge. Thus, in the cutting process for forming the slit hole, it is easy to ensure the portion clamped by the mold. Therefore, the slit hole can be properly formed at the stator during the cutting process. In addition, the outer connecting portion will not be too long, so it is easy to ensure the radial length of the stator wing. Therefore, the exhaust performance of the vacuum pump can be improved.

[0023] The radial length of the inner connecting portion of the metal plate that connects the stator blade of the stator to the inner peripheral edge formed by the cutting process can also be smaller than the radial length of the inner peripheral edge. Thus, in the cutting process for forming the slit hole, it is easy to ensure the portion clamped by the mold. Therefore, the slit hole can be properly formed at the stator during the cutting process. In addition, the inner connecting portion will not be too long, so it is easy to ensure the radial length of the stator blade. Therefore, the exhaust performance of the vacuum pump can be improved.

[0024] The upstream ridgeline of the stator blade of the vacuum pump configured as described above is arranged with a constant gap with high dimensional accuracy relative to the surface where the downstream end of the rotor blade is arranged. Therefore, the backflow of gas can be suppressed and the exhaust performance of the vacuum pump can be improved.

[0025] By installing the stator for a vacuum pump constructed as described above into a vacuum pump, the upstream ridgeline of the stator blade can be arranged with a constant gap with high dimensional accuracy relative to the surface where the downstream end of the rotor blade is arranged. Therefore, the backflow of gas can be suppressed and the exhaust performance of the vacuum pump can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a cross-sectional view showing the vacuum pump according to the first embodiment.

[0027] Figure 2 It is a top view showing the stator.

[0028] Figure 3 This is a perspective view of a part of the stator enlarged.

[0029] Figure 4 It is a top view showing a metal plate before cutting.

[0030] Figure 5 The figures are for explaining the manufacturing process of the stator, (A) is a top view after cutting, and (B) is a top view after bending.

[0031] Figure 6 is a diagram showing a portion of a stator after bending, (A) is from Figure 5 (B) is a side view of the object as viewed from the arrow line A. (B) is a side view of the object as viewed from the arrow line A. Figure 5 (B) is a side view taken along the arrow line B, and (C) is a side view taken along the arrow line B. Figure 5 (B) is a front view taken along the arrow line C.

[0032] Figure 7 This is a diagram showing the arrangement of stator blades (wings) and rotor blades of a vacuum pump in which a stator is incorporated.

[0033] Figure 8The drawings show the manufacturing process of the stator of the vacuum pump according to the second embodiment, wherein (A) is a plan view after cutting, and (B) is a plan view after bending.

[0034] Fig. 9 is a diagram showing a portion of a stator after bending, (A) is from Figure 8 (B) is a side view of the object as viewed from the arrow line A. (B) is a side view of the object as viewed from the arrow line A. Figure 8 (B) is a side view taken along the arrow line B, and (C) is a side view taken along the arrow line B. Figure 8 (B) is a front view taken along the arrow line C.

[0035] Fig.10 The drawings show the manufacturing process of the stator of the vacuum pump according to the third embodiment, wherein (A) is a plan view after cutting, and (B) is a plan view after bending.

[0036] Fig.11 is a diagram showing a portion of a stator after bending, (A) is from Fig.10 (B) is a side view of the object as viewed from the arrow line A. (B) is a side view of the object as viewed from the arrow line A. Fig.10 (B) is a side view taken along the arrow line B, and (C) is a side view taken along the arrow line B. Fig.10 (B) is a front view taken along the arrow line C.

[0037] Fig.12 The drawings show the manufacturing process of the stator of the vacuum pump according to the fourth embodiment, wherein (A) is a plan view after cutting, and (B) is a plan view after bending.

[0038] Fig.13 The drawings are plan views after cutting showing modified examples of the stator according to the fourth embodiment, wherein (A) shows a first modified example and (B) shows a second modified example. DETAILED DESCRIPTION

[0039] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the dimensions of the accompanying drawings are exaggerated for the convenience of description and may differ from the actual dimensions. In addition, in this specification and the accompanying drawings, the same reference numerals are used to indicate the structural elements having substantially the same functional structure, thereby omitting repeated descriptions.

[0040] <First embodiment>

[0041] A vacuum pump 1 according to a first embodiment of the present invention is Figure 1 1 is a turbomolecular pump in which a rotor 30 having rotor blades 32 rotates at high speed to eject gas molecules. The vacuum pump 1 includes a vacuum pump body 2 for sucking and discharging gas and a control device 3 for controlling the vacuum pump body 2 .

[0042] The vacuum pump body 2 sucks and discharges gas from a cavity such as a semiconductor manufacturing device. The vacuum pump body 2 includes a cylindrical first cover 10 forming an air intake port 11, a second cover 20 forming an air exhaust port 21, a stator column 22 fixed to the second cover 20, a stationary wing portion 40, and a threaded spacer 90. Furthermore, the vacuum pump body 2 includes a rotating rotor 30, a bearing that rotatably supports the rotor 30, a displacement sensor that detects displacement of the rotor 30, and a motor 80 (driving unit) that rotationally drives the rotor 30.

[0043] The first cover 10 is located at the upper part of the vacuum pump body 2, and has an air inlet 11 formed at the upper end. The first cover 10 is fixed by bolts 12 to the second cover 20 disposed at the bottom thereof.

[0044] The rotor 30 is rotatably arranged inside the first cover 10. The rotor 30 includes a shaft 35, a plurality of rotor blades 32 in the axial direction, and a cylindrical portion 33 arranged downstream of the rotor blades 32. The rotor blades 32 are blades for forming a turbomolecular pump to suck and discharge gas. The plurality of rotor blades 32 in each stage are radially arranged in the circumferential direction.

[0045] The rotor 30 is substantially cylindrical in shape, and the shaft 35 is fixedly passed through the inside. Each rotor blade 32 is formed to be inclined at a predetermined angle from a plane perpendicular to the axial direction of the shaft 35 in order to transfer the molecules of the exhaust gas downward by collision. The rotor blade 32 is formed integrally with the outer peripheral surface of the rotor 30. Alternatively, the rotor blade 32 may be fixed to the outer peripheral surface of the rotor 30.

[0046] The cylindrical portion 33 is disposed downstream of the rotor blade 32 and is formed in a cylindrical shape. The cylindrical portion 33 is formed so as to protrude toward the inner peripheral surface of the threaded spacer 90. The cylindrical portion 33 is close to the inner peripheral surface of the threaded spacer 90 with a predetermined gap therebetween.

[0047] The shaft 35 is arranged at the rotation center of the rotor 30. The shaft 35 has a cylindrical main shaft portion 36 and a disc-shaped disk 37 arranged at the lower part of the main shaft portion 36. The main shaft portion 36 and the disk 37 are formed of a high magnetic permeability material (iron, etc.) that can be attracted by magnetism. The main shaft portion 36 is attracted by the magnetic force of the upstream radial electromagnet 61 and the downstream radial electromagnet 62 described later to control the position.

[0048] The bearing is, for example, a so-called 5-axis controlled magnetic bearing, which supports the shaft 35 in a floating manner and controls its position. The bearing has an upstream radial electromagnet 61 that attracts the upstream side of the main shaft portion 36, a downstream radial electromagnet 62 that attracts the downstream side of the main shaft portion 36, axial electromagnets 63A and 63B that attract the disk 37, and an auxiliary bearing 65. The auxiliary bearing 65 contacts the main shaft portion 36 when the shaft vibration of the rotor 30 increases, thereby preventing the rotor 30 from being directly in contact with the stator side and being damaged.

[0049] The upstream radial electromagnet 61 has four electromagnets arranged in pairs on a plane perpendicular to the rotation axis, in each of two axes orthogonal to each other. The downstream radial electromagnet 62 has four electromagnets arranged in pairs on a plane perpendicular to the rotation axis, in each of two axes orthogonal to each other. The axial electromagnets 63A and 63B are arranged to sandwich the disk 37 from top to bottom.

[0050] The displacement sensor is arranged on the stator column 22 to detect the displacement of the rotor 30. The displacement sensor includes an upstream radial sensor 71, a downstream radial sensor 72, and an axial sensor 73. The upstream radial sensor 71 is four non-contact type sensors arranged close to and corresponding to the four upstream radial electromagnets 61. The upstream radial sensor 71 is configured to detect the radial displacement of the upper part of the main shaft portion 36 of the shaft 35, and transmit its displacement signal to the control device 3. Examples of sensors used as the upstream radial sensor 71 include an inductive sensor, an eddy current sensor, and the like.

[0051] The downstream radial sensors 72 are four non-contact sensors disposed close to and corresponding to the four downstream radial electromagnets 62. The downstream radial sensors 72 are configured to detect radial displacement of the lower portion of the main shaft portion 36 and transmit displacement signals thereof to the control device 3. Examples of sensors used as the downstream radial sensors 72 include inductive sensors, eddy current sensors, and the like.

[0052] The axial direction sensor 73 is disposed below the disk 37. The axial direction sensor 73 is configured to detect the axial displacement of the shaft 35 and transmit the displacement signal to the control device 3.

[0053] The control device 3 controls the excitation of the upstream radial electromagnet 61 via a compensation circuit having a PID adjustment function based on the displacement signal detected by the upstream radial sensor 71, thereby adjusting the radial position of the upstream side of the main shaft portion 36. This adjustment is performed independently on each of the two orthogonal axes on a plane perpendicular to the rotation axis.

[0054] Furthermore, the control device 3 controls the excitation of the downstream radial electromagnet 62 via a compensation circuit having a PID adjustment function based on the displacement signal detected by the downstream radial sensor 72, thereby adjusting the radial position of the downstream side of the main shaft portion 36. This adjustment is performed independently on each of the two orthogonal axes on a plane perpendicular to the rotation axis.

[0055] Furthermore, the control device 3 controls the excitation of the axial electromagnets 63A and 63B based on the displacement signal detected by the axial sensor 73. At this time, the axial electromagnet 63A attracts the disk 37 upward by the magnetic force, and the axial electromagnet 63B attracts the disk 37 downward. In this way, the magnetic bearing can magnetically levitate the shaft 35 and rotatably support it in a non-contact manner by appropriately adjusting the magnetic force affecting the shaft 35.

[0056] The motor 80 includes a plurality of permanent magnets, namely, magnetic poles 81 disposed on the rotor side and a motor electromagnet 82 disposed on the stator side. The motor electromagnet 82 applies a torque component for rotating the shaft 35 to the magnetic poles 81. The rotor 30 is thereby driven to rotate.

[0057] The motor 80 is provided with a rotation speed sensor and a motor temperature sensor (not shown). The rotation speed sensor and the motor temperature sensor transmit detection results to the control device 3 as detection signals. The control device 3 uses the signals received from the rotation speed sensor and the motor temperature sensor to control the rotation of the shaft 35.

[0058] The stationary blade portion 40 includes a plurality of stages of stators 41 and a plurality of stator spacers 42 stacked so as to be sandwiched between the stators 41 of each stage. Each stator 41 includes a plurality of stator blades 43 .

[0059] The stator blade 43 is formed to be inclined at a predetermined angle from a plane perpendicular to the axial direction of the shaft 35, similarly to the rotor blade 32. The stator blade 43 is arranged alternately with the steps of the rotor blade 32 toward the inner side of the first cover 10. The end of the outer peripheral side of the stator blade 43 is supported by being sandwiched between a plurality of stacked annular stator spacers 42. The stator spacers 42 are stacked and arranged inside the first cover 10. The stator spacers 42 are made of metals such as aluminum, iron, stainless steel, copper, or alloys containing these metals as components.

[0060] The threaded spacer 90 is arranged between the lower part of the stator spacer 42 and the second cover 20. The threaded spacer 90 is close to the cylindrical portion 33 of the rotor 30 which is arranged in a cylindrical shape with a predetermined gap therebetween. A plurality of spiral thread grooves 91 are formed on the inner circumferential surface of the threaded spacer 90. The spiral direction of the thread groove 91 is the direction in which the molecules of the exhaust gas are transferred to the exhaust port 21 when the molecules of the exhaust gas move along the rotation direction of the rotor 30. The threaded spacer 90 and the cylindrical portion 33 constitute a thread groove pump. The threaded spacer 90 is made of a metal such as aluminum, copper, stainless steel, iron, or an alloy containing these metals as components.

[0061] The second cover 20 is a disc-shaped component constituting the bottom of the vacuum pump body 2. The second cover 20 is formed with an exhaust port 21 at the lower part of the threaded spacer 90. The exhaust port 21 is connected to the outside. The second cover 20 is generally made of metal such as iron, aluminum, stainless steel, etc. The second cover 20 preferably physically holds the vacuum pump body 2 and also has the function of a heat conduction path. Therefore, the constituent material of the second cover 20 is preferably a metal with rigidity and high thermal conductivity, for example, iron, aluminum, copper, etc. can be suitably used.

[0062] When the shaft 35 of the vacuum pump body 2 is driven by the motor 80 , the rotor blades 32 and the cylindrical portion 33 rotate. Thus, the exhaust gas from the chamber is sucked through the air inlet 11 by the action of the rotor blades 32 and the stator blades 43 .

[0063] The exhaust gas sucked from the air intake port 11 is transferred to the second cover 20 via the rotor blade 32 and the stator blade 43. At this time, the temperature of the rotor blade 32 rises due to the frictional heat generated when the exhaust gas contacts the rotor blade 32, the conduction of heat generated at the motor 80, etc. However, this heat is transferred to the stator blade 43 side by radiation or conduction of gas molecules of the exhaust gas, etc. Furthermore, the stator spacers 42 are joined to each other at the outer periphery. Therefore, the heat received by the stator blade 43 from the rotor blade 32, the frictional heat generated when the exhaust gas contacts the stator blade 43, etc. are transferred to the outside via the stator spacers 42.

[0064] Furthermore, the exhaust gas transferred to the second cover 20 is guided by the thread groove 91 of the threaded spacer 90 and transferred to the exhaust port 21 .

[0065] In the present embodiment, the threaded spacer 90 is disposed on the outer periphery of the cylindrical portion 33, and a thread groove 91 is formed on the inner peripheral surface of the threaded spacer 90. However, on the contrary, a thread groove may be formed on the outer peripheral surface of the cylindrical portion 33, and a spacer having a cylindrical inner peripheral surface may be disposed around the threaded spacer 90.

[0066] In addition, in order to prevent the gas sucked from the air intake port 11 from intruding into the electric equipment side composed of the motor 80, the downstream radial electromagnet 62, the downstream radial sensor 72, the upstream radial electromagnet 61, the upstream radial sensor 71, etc., the outer periphery of the electric equipment is covered by the stator column 22. The inside of the stator column 22 surrounding the electric equipment is maintained at a predetermined pressure by flushing gas. The second cover 20 is provided with a pipe (not shown), through which flushing gas is introduced. The introduced flushing gas passes through the gap between the auxiliary bearing 65 and the shaft 35, between the motor 80, and between the stator column 22 and the rotor blade 32 and is sent to the exhaust port 21.

[0067] A heater (not shown) and a ring-shaped water cooling pipe 23 are wound around the outer periphery of the second cover 20. In addition, a temperature sensor (for example, a thermistor) (not shown) is embedded in the second cover 20. Based on the signal of the temperature sensor, the heating of the heater and the cooling of the water cooling pipe 23 are controlled so that the temperature of the second cover 20 is maintained at a certain high temperature (set temperature). In this way, the process gas is prevented from being attached and accumulated inside the vacuum pump body 2.

[0068] The processing gas may be introduced into the chamber at a high temperature to improve the reactivity. When these processing gases are discharged, they are cooled and solid at a certain temperature, and products may be precipitated into the exhaust system. In addition, such processing gases are solid at a low temperature in the vacuum pump body 2, and adhere to the inside of the vacuum pump body 2 and accumulate.

[0069] For example, when Al etching equipment uses SiCl4 as the processing gas, low vacuum (1×10 5 [Pa]~1[Pa]) and low temperature (about 20[℃]), solid products (such as AlCl3) precipitate and accumulate inside the vacuum pump body 2. If the precipitate of the processing gas accumulates inside the vacuum pump body 2, the accumulation narrows the flow path of the pump, which becomes a cause of the performance degradation of the vacuum pump body 2. For example, the aforementioned product is easy to solidify and adhere in the low temperature part near the exhaust port 21, especially near the cylindrical part 33 and the threaded spacer 90. Therefore, the control device 3 controls the heating of the heater and the cooling of the water-cooling pipe 23 based on the signal of the temperature sensor in a manner to maintain the temperature of the second cover 20 at a certain higher temperature (set temperature). In this way, it is possible to suppress the processing gas from adhering and accumulating inside the vacuum pump body 2.

[0070] At least one stator 41 such as Figure 2 As shown, there are two split stators 41A formed by dividing the ring shape into two parts at 180 degrees in a manner that can be inserted from the radially outer side between the rotor blades 32 arranged in the axial direction. The split stator 41A is formed by cutting and bending a metal plate. The cutting process is a shearing process using a die and a punch of a mold. The cutting process and the bending process can be performed separately or simultaneously. The cutting process and the bending process are preferably performed continuously by feeding the metal plate with a sequential feed type (sequential feed type) pressurizing die. The split stator 41A is as shown in FIG. Figure 2 , 3As shown in FIG. 1 , the stator 41 includes an inner peripheral edge 44 located on the inner peripheral side, an outer peripheral edge 45 located on the outer peripheral side, a plurality of stator blades 43 arranged between the inner peripheral edge 44 and the outer peripheral edge 45, an inner connecting portion 46 connecting the stator blade 43 and the inner peripheral edge 44, and an outer connecting portion 47 connecting the stator blade 43 and the outer peripheral edge 45. The inner connecting portion 46 and the outer connecting portion 47 are formed shorter than the stator blade 43 in the circumferential direction of the stator 41. Slit holes 48 punched by cutting are formed between the stator blades 43 arranged in the circumferential direction. Aluminum or the like can be used as the material of the metal plate constituting the stator 41 as appropriate. The slit holes 48 include an outer slit 48A extending in the circumferential direction on the inner peripheral side of the outer peripheral edge 45, an inner slit 48B extending in the circumferential direction on the outer peripheral side of the inner peripheral edge 44, and a central slit 48C extending between the outer slit 48A and the inner slit 48B. The central slit 48C communicates the central portion of the outer slit 48A in the circumferential direction of the stator 41 and the central portion of the inner slit 48B in the circumferential direction of the stator 41. Each slit has a length in the extending direction and a width in a direction perpendicular to the extending direction.

[0071] Next, the manufacturing process of the stator 41 is described. Figure 4 As shown in FIG. 1 , a semi-ring-shaped metal plate is prepared as a raw material. The semi-ring-shaped metal plate can also be formed by cutting, but the processing method is not particularly limited. Next, the portion indicated by the single-point chain line is cut by cutting using a die. Thus, as shown in FIG. Figure 5 As shown in FIG. 1A , slit holes 48 are formed between stator blades 43 arranged in the circumferential direction. The slit holes 48 include an outer end 49 as an end on the inner circumference side of the outer peripheral edge 45, an inner end 50 as an end on the outer circumference side of the inner peripheral edge 44, two outer connecting end portions 51 as ends of the outer connecting portion 47 in the circumferential direction, two inner connecting end portions 52 as ends of the inner connecting portion 46 in the circumferential direction, and two stator blade end portions 53 as ends of the stator blade 43. Each stator blade end portion 53 includes a stator blade outer end portion 53A located on the outer circumference side of the stator blade 43, a stator blade inner end portion 53B located on the inner circumference side of the stator blade 43, and a stator blade side end portion 53C extending in the radial direction of the stator 41 between the stator blade outer end portion 53A and the stator blade inner end portion 53B. The width and / or length of the slit hole 48 is preferably 0.2 times or more, more preferably 0.5 times or more, further preferably 0.7 times or more, further preferably 1 times or more of the thickness of the metal plate. Thus, the mold for cutting the slit hole 48 will not be too thin, and damage to the mold can be suppressed.

[0072] A first corner portion C1 is formed between the outer end portion 49 and the outer connecting end portion 51. A corner portion refers to a portion where a recess is formed on the wall surface constituting the slit hole 48. A second corner portion C2 is formed between the outer connecting end portion 51 and the stator wing outer end portion 53A. A third corner portion C3 is formed between the stator wing inner end portion 53B and the inner connecting end portion 52. A fourth corner portion C4 is formed between the inner end portion 50 and the inner connecting end portion 52. The first corner portion C1, the second corner portion C2, the third corner portion C3 and the fourth corner portion C4 are preferably formed by curved surfaces. The radius of curvature of the first corner portion C1, the second corner portion C2, the third corner portion C3 and the fourth corner portion C4 is preferably greater than 0.2 mm, more preferably greater than 0.3 mm, and further preferably greater than 0.5 mm. Thus, it is possible to prevent stress concentration at each corner portion and damage to the stator 41.

[0073] The first corner E1 is formed at the junction of the stator wing outer end 53A and the stator wing side end 53C. The corner refers to a portion where a convex portion is formed on the wall surface constituting the slit hole 48. The second corner E2 is formed at the junction of the stator wing inner end 53B and the stator wing side end 53C. The first corner E1 and the second corner E2 are preferably formed by sharp angles without curvature. Thereby, it is possible to suppress the gap between the stator wing outer end 53A and the rotor wing 32 from becoming larger, and it is possible to suppress the reduction in exhaust efficiency. In addition, the first corner E1 and the second corner E2 may also be formed with a curvature radius.

[0074] The two stator blade side ends 53C arranged on each stator blade 43 are formed by straight lines and are parallel when viewed from the out-of-plane direction of the metal plate. When viewed from the out-of-plane direction of the metal plate, the inclined center line X passing through the center of the inner connecting portion 46 in the circumferential direction and the center of the outer connecting portion 47 in the circumferential direction are parallel to the two stator blade side ends 53C of each stator blade 43. The distance L1 from the inclined center line X to each stator blade side end 53C may be the same or different.

[0075] Each slit hole 48 is located between two adjacent stator blades 43. Therefore, the two stator blade side ends 53C formed in each slit hole 48 are the stator blade side ends 53C of different stator blades 43 adjacent in the circumferential direction. In each slit hole 48, the length W between two adjacent stator blade side ends 53C in the circumferential direction of the stator 41 increases from the inner peripheral side to the outer peripheral side of the stator blade 43.

[0076] The length L3 of the slit hole 48 adjacent to the outer peripheral edge 45 in the radial direction of the stator 41 is preferably smaller than the length L2 of the outer peripheral edge 45 in the radial direction. Therefore, in the cutting process for forming the slit hole 48, a portion clamped by the die can be sufficiently secured on the radially outer side of the slit hole 48. In addition, if a portion clamped by the die cannot be sufficiently secured, it may be difficult to form the slit hole 48. Therefore, in the cutting process, the slit hole 48 (particularly the outer slit 48A adjacent to the outer peripheral edge 45) can be appropriately formed in the stator 41.

[0077] In addition, the length L4 of the slit hole 48 adjacent to the inner peripheral edge 44 in the radial direction of the stator 41 is preferably smaller than the length L5 of the inner peripheral edge 44 in the radial direction. Therefore, in the cutting process for forming the slit hole 48, a portion clamped by the mold can be sufficiently secured on the radial inner side of the slit hole 48. In addition, in the case where the portion clamped by the mold cannot be sufficiently secured, it is difficult to form the slit hole 48. Therefore, in the cutting process, the slit hole 48 (particularly the inner slit 48B adjacent to the inner peripheral edge 44) can be appropriately formed in the stator 41.

[0078] The length L6 of the outer connecting portion 47 in the radial direction of the stator 41 is preferably smaller than the length L2 of the outer peripheral edge 45 in the radial direction. Thus, in the cutting process for forming the slit hole 48, a portion clamped by a mold can be sufficiently ensured. Therefore, the slit hole 48 can be appropriately formed in the stator 41 in the cutting process. In addition, the outer connecting portion 47 is not too long, so the radial length of the stator blade 43 can be sufficiently ensured. Therefore, the exhaust performance of the vacuum pump 1 can be improved.

[0079] In addition, the length L7 of the inner connecting portion 46 in the radial direction of the stator 41 is preferably smaller than the length L5 of the inner peripheral edge 44 in the radial direction. As a result, in the cutting process for forming the slit hole 48, a portion clamped by a mold can be sufficiently ensured. Therefore, the slit hole 48 can be appropriately formed in the stator 41 in the cutting process. In addition, the inner connecting portion 46 is not too long, so the radial length of the stator blade 43 can be sufficiently ensured. Therefore, the exhaust performance of the vacuum pump 1 can be improved.

[0080] After the slit holes 48 are formed in the metal plate, the metal plate is subjected to a bending process using a die. Figure 5As shown in (B) and 6, the outer connecting portion 47 and the inner connecting portion 46 are twisted around the tilt center line X, and the stator blade 43 is tilted relative to the outer peripheral edge 45 and the inner peripheral edge 44. The tilt angle θ of the stator blade 43 relative to the outer peripheral edge 45 is constant from the outer peripheral side to the inner peripheral side of the stator blade 43. In addition, the tilt angle θ at the portion of the stator blade 43 connected to the outer connecting portion 47 and the inner connecting portion 46 is affected by the twist of the outer connecting portion 47 and the inner connecting portion 46, and may be slightly different from the constant tilt angle θ.

[0081] Thereafter, the stator 41 is Figure 7 As shown, the vacuum pump 1 is installed. The stator blade 43 is inclined relative to the outer peripheral edge 45, so the upstream side ridge line 54 is formed at a position far from the surface where the outer peripheral edge 45 is located at the stator blade side end 53C located at the upstream side of the outer peripheral edge 45. The ridge line is formed at the boundary between the wall surface of the slit hole 48 and the surface of the metal plate. In addition, the upstream side ridge line 54 is arranged at a constant (constant) height H from the outer peripheral edge 45 and the inner peripheral edge 44 to the upstream side. The upstream side ridge line 54 is arranged at a constant gap S in the axial direction relative to the rotor blade lower side reference surface P1 where the end of the downstream side of the rotor blade 32 facing the upstream side is located. That is, the entire upstream side ridge line 54 is arranged with a high dimensional accuracy and an appropriate gap S relative to the rotor blade 32. Therefore, it is difficult for gas to flow back between the stator blade 43 and the rotor blade 32, and the exhaust performance of the vacuum pump 1 can be improved. Furthermore, when the stator blade 43 is inclined, a downstream ridgeline 55 is formed at a position farther from the surface where the outer peripheral edge 45 is located at the stator blade side end portion 53C located at the downstream side than the outer peripheral edge 45. And the downstream ridgeline 55 is arranged at a constant height H from the outer peripheral edge 45 and the inner peripheral edge 44 toward the downstream side. In addition, the height H of the upstream ridgeline 54 and the height H of the downstream ridgeline 55 may be the same or different. The downstream ridgeline 55 is arranged at a constant gap S in the axial direction with respect to the rotor blade upper side reference surface P2 where the upstream end of the rotor blade 32 facing the downstream side is located. That is, the entire downstream ridgeline 55 is arranged with a suitable gap S with high dimensional accuracy relative to the rotor blade 32. Therefore, it is difficult for gas to flow back between the stator blade 43 and the rotor blade 32, and the exhaust performance of the vacuum pump 1 can be improved.

[0082] <Second embodiment>

[0083] The vacuum pump 1 of the second embodiment is as follows Figure 8 , 9 As shown, only the shapes of the slit holes 48 and the stator blades 43 of the stator 41 are different from those of the first embodiment. Figure 8As shown in (A), the two stator blade side ends 53C of the slit hole 48 are formed as parallel straight lines when viewed from the outward direction of the metal plate. Therefore, in each slit hole 48, the length W between two adjacent stator blade side ends 53C in the circumferential direction of the stator 41 is constant from the inner circumference side to the outer circumference side of the stator blade 43. The distance L1 from the inclined center line X to the stator blade side end 53C increases from the inner circumference side to the outer circumference side of the stator blade 43.

[0084] After the slit holes 48 are formed in the metal plate, the metal plate is subjected to a bending process using a die. Figure 8 As shown in (B) and 9, the outer connecting portion 47 and the inner connecting portion 46 are twisted around the inclined center line X, and the stator blade 43 is inclined relative to the outer peripheral edge 45 and the inner peripheral edge 44. The upstream side ridgeline 54 of the stator blade side end 53C is arranged at a constant height H from the outer peripheral edge 45 and the inner peripheral edge 44 to the upstream side. In addition, the upstream side ridgeline 54 is formed by a curve (refer to Figure 8 (B)). When the stator 41 is installed in the vacuum pump 1, the upstream ridgeline 54 is aligned with the rotor blade lower side reference plane P1 (refer to Figure 7 ) is arranged with a constant gap S in the axial direction. That is, the entire upstream side ridgeline 54 is arranged with a high dimensional accuracy and an appropriate gap S relative to the rotor blade 32. Therefore, it is difficult for gas backflow to occur between the stator blade 43 and the rotor blade 32, and the exhaust performance of the vacuum pump 1 can be improved. In order to form such a stator blade side end 53C, the inclination angle θ of the stator blade 43 relative to the outer peripheral edge 45 gradually increases from the outer peripheral side to the inner peripheral side of the stator blade 43. That is, the inclination angle θ on the inner peripheral side where the distance from the inclination center line X to the stator blade side end 53C is shorter becomes larger. Therefore, as Fig. 9 As shown, the inclination angle θ1 at the inner peripheral end of the stator blade side end 53C is larger than the inclination angle θ2 at the outer peripheral end of the stator blade side end 53C. The inclination angle θ at this time is considered to change in direct proportion to a linear function or in a curved manner with respect to the radial direction.

[0085] In addition, the downstream side ridgeline 55 of the stator blade side end portion 53C is arranged at a constant height H from the outer peripheral edge 45 and the inner peripheral edge 44 toward the downstream side. And the downstream side ridgeline 55 is formed by a curve (see Figure 8 (B)) The downstream ridgeline 55 is relative to the rotor blade upper side reference plane P2 (refer to Figure 7 ), and are arranged with a constant gap S in the axial direction. That is, the entire downstream side ridgeline 55 is arranged with a suitable gap S with high dimensional accuracy relative to the rotor blade 32. Therefore, it is difficult for gas to flow back between the stator blade 43 and the rotor blade 32, and the exhaust performance of the vacuum pump 1 can be improved.

[0086] <Third embodiment>

[0087] The vacuum pump 1 of the third embodiment is as follows Fig.10 , 11 As shown, only the shapes of the slit holes 48 and the stator blades 43 of the stator 41 are different from those of the first embodiment. Fig.10 As shown in (A), each slit hole 48 is processed so that the length W between two adjacent stator blade side ends 53C in the circumferential direction of the stator 41 decreases from the inner peripheral side to the outer peripheral side of the stator blade 43. The distance L1 from the inclined center line X to the stator blade side end 53C increases from the inner peripheral side to the outer peripheral side of the stator blade 43.

[0088] After the slit holes 48 are formed in the metal plate, the metal plate is subjected to a bending process using a die. Fig.10 As shown in (B) and 11, the outer connecting portion 47 and the inner connecting portion 46 are twisted around the inclined center line X, and the stator blade 43 is inclined relative to the outer peripheral edge 45 and the inner peripheral edge 44. The upstream side ridgeline 54 of the stator blade side end 53C is arranged at a constant height H from the outer peripheral edge 45 and the inner peripheral edge 44 to the upstream side. In addition, the upstream side ridgeline 54 is formed by a curve (refer to Fig.10 (B)). When the stator 41 is installed in the vacuum pump 1, the upstream ridgeline 54 is aligned with the rotor blade lower side reference plane P1 (refer to Figure 7 ) is arranged with a constant gap S in the axial direction. That is, the entire upstream side ridgeline 54 is arranged with a high dimensional accuracy and an appropriate gap S relative to the rotor blade 32. Therefore, it is difficult for gas backflow to occur between the stator blade 43 and the rotor blade 32, and the exhaust performance of the vacuum pump 1 can be improved. In order to form such a stator blade side end 53C, the inclination angle θ of the stator blade 43 relative to the outer peripheral edge 45 gradually increases from the outer peripheral side to the inner peripheral side of the stator blade 43. That is, the inclination angle θ on the inner peripheral side where the distance from the inclination center line X to the stator blade side end 53C is shorter becomes larger. Therefore, as Fig.11 As shown, the inclination angle θ1 at the inner peripheral end of the stator blade side end 53C is larger than the inclination angle θ2 at the outer peripheral end of the stator blade side end 53C. The inclination angle θ at this time is considered to change in direct proportion to a linear function or in a curved manner with respect to the radial direction.

[0089] In addition, the downstream side ridgeline 55 of the stator blade side end portion 53C is arranged at a constant height H from the outer peripheral edge 45 and the inner peripheral edge 44 toward the downstream side. And, the downstream side ridgeline 55 is formed by a curve (see Fig.10 (B)) The downstream ridgeline 55 is relative to the rotor blade upper reference plane P2 (refer to Figure 7), and are arranged with a constant gap S in the axial direction. That is, the entire downstream side ridgeline 55 is arranged with a suitable gap S with high dimensional accuracy relative to the rotor blade 32. Therefore, it is difficult for gas to flow back between the stator blade 43 and the rotor blade 32, and the exhaust performance of the vacuum pump 1 can be improved.

[0090] <Fourth embodiment>

[0091] The vacuum pump 1 of the fourth embodiment is as follows Fig.12 As shown, only the shapes of the slit holes 48 and the stator blades 43 of the stator 41 are different from those of the first embodiment. Fig.12 As shown in (A), the two stator wing side ends 53C are formed into a curve when the slit hole 48 is observed from the outward direction of the metal plate. At each slit hole 48, the length W between two adjacent stator wing side ends 53C in the circumferential direction of the stator 41 changes from the inner circumference to the outer circumference of the stator 41. In addition, the distance L1 from the inclined center line X to the stator wing side end 53C changes from the inner circumference to the outer circumference of the stator wing 43. The stator wing side end 53C is a curve that is concave in the direction away from the inclined center line X. In addition, the stator wing side end 53C may be like Fig.13 (A) is a first variation of the fourth embodiment, which is a convex curve in the direction away from the inclined center line X. In addition, it can also be like Fig.13 As in the second modified example of the fourth embodiment shown in FIG. 2 (B), one of the two stator blade side ends 53C forming the slit hole 48 is a curve that is concave in the direction away from the inclined center line X, and the other is a curve that is convex in the direction away from the inclined center line X. The two curved stator blade side ends 53C forming the slit hole 48 may be parallel or non-parallel.

[0092] In the fourth embodiment, if Fig.12 (A), 13, after the metal plate is formed with a slit hole 48, as shown in Fig.12 As shown in (B), the metal plate is subjected to a bending process using a mold. As a result, the outer connecting portion 47 and the inner connecting portion 46 are twisted around the inclined center line X, and the stator blade 43 is inclined relative to the outer peripheral edge 45 and the inner peripheral edge 44. The upstream side ridge line 54 of the stator blade side end portion 53C is arranged at a constant height H from the outer peripheral edge 45 and the inner peripheral edge 44 toward the upstream side. In addition, the upstream side ridge line 54 is formed by a curve. In addition, a part or all of the upstream side ridge line 54 may be formed by a straight line. When the stator 41 is installed in the vacuum pump 1, the upstream side ridge line 54 is relative to the rotor blade lower side reference plane P1 (refer to Figure 7) is arranged with a constant gap S in the axial direction. That is, the entire upstream ridgeline 54 is arranged with a suitable gap S with high dimensional accuracy relative to the rotor blade 32. Therefore, it is difficult for gas to flow back between the stator blade 43 and the rotor blade 32, and the exhaust performance of the vacuum pump 1 can be improved. In order to form such a stator blade side end 53C, the inclination angle θ of the stator blade 43 with respect to the outer peripheral edge 45 changes from the outer peripheral side to the inner peripheral side of the stator blade 43.

[0093] In addition, the downstream ridgeline 55 of the stator blade side end 53C is arranged at a constant height H from the outer peripheral edge 45 and the inner peripheral edge 44 toward the downstream side. And the downstream ridgeline 55 is formed by a curve. In addition, part or all of the downstream ridgeline 55 may be formed by a straight line. The downstream ridgeline 55 is relative to the rotor blade upper side reference plane P2 (refer to the reference plane P2) where the upstream end of the rotor blade 32 facing the downstream side is located. Figure 7 ), and are arranged with a constant gap S in the axial direction. That is, the entire downstream ridgeline 55 is arranged with a suitable gap S with high dimensional accuracy relative to the rotor blade 32. Therefore, it is difficult for gas to flow back between the stator blade 43 and the rotor blade 32, and the exhaust performance of the vacuum pump 1 can be improved.

[0094] In addition, the present invention is not limited to the above-mentioned embodiment, and various changes can be made by those skilled in the art within the technical concept of the present invention. For example, the bearing may not be a magnetic bearing. In addition, in the above-mentioned embodiment, the stator blade 43 has a portion located on the upstream side of the outer peripheral edge 45 and a portion located on the downstream side, but it may not have a portion located on the downstream side.

[0095] Description of Reference Numerals

[0096] 1 Vacuum pump

[0097] 2 Vacuum pump body

[0098] 10 No.1 Cover

[0099] 11 Inhalation port

[0100] 20 No.2 Cover

[0101] 21 Exhaust port

[0102] 30 rotors

[0103] 32 rotor wings

[0104] 40Static Wing Department

[0105] 41 stator

[0106] 41A split stator

[0107] 43 stator wing

[0108] 44 Inner edge

[0109] 45 Outer edge

[0110] 46Inside connection

[0111] 47 Outer connection part

[0112] 48 slit holes

[0113] 49 outer end

[0114] 50 inner end

[0115] 51 Outer connection end

[0116] 52Inner connection end

[0117] 53 stator wing end

[0118] 53A stator wing outer end

[0119] 53B stator wing inner end

[0120] 53C stator wing side end

[0121] 54 Upstream side ridgeline

[0122] 55 downstream ridgeline

[0123] 80 Motor (drive unit)

[0124] C1 1st corner

[0125] C2 2nd corner

[0126] C3 3rd corner

[0127] C4 4th corner

[0128] E1 1st corner

[0129] E2 2nd corner

[0130] P1 rotor blade lower side reference surface

[0131] P2 rotor blade upper reference surface

[0132] θ is the tilt angle.

Claims

1. A method for manufacturing a vacuum pump, the vacuum pump comprising a first cover, a second cover, a rotor, a plurality of rotor blades, a stator, a drive unit, and a bearing. The first cover has an air intake port. The second cover has an exhaust port. The rotor is disposed in a space sealed at least by the first cover and the second cover, and has a shaft. The plurality of rotor blades are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor. The stators are arranged alternately with the rotor blades in the axial direction of the shaft. The driving unit drives the shaft to rotate. The bearing supports the shaft so that it can rotate. The method for manufacturing the vacuum pump is characterized by comprising the following steps: Cutting the metal plate so that an outer peripheral edge located at an outer peripheral end of the stator, an inner peripheral edge located at an inner peripheral end of the stator, and a plurality of stator blades located between the outer peripheral edge and the inner peripheral edge are integrally formed, and a stator blade end portion which is an end portion of the stator blade in a circumferential direction of the stator is formed linearly from the inner peripheral end to the outer peripheral end of the stator blade; The metal plate is subjected to a bending process, thereby bending the stator blade so that the inclination angle of the stator blade relative to the outer peripheral edge changes in a curved line from the inner peripheral side end to the outer peripheral side end of the stator blade; The rotor blade is arranged such that an upstream ridgeline of the stator blade end portion located on the upstream side of the stator blade is a curved line from the inner peripheral side end to the outer peripheral side end of the stator blade, and the axial gap is constant with respect to a surface of the downstream side end portion of the rotor blade arranged opposite to the upstream ridgeline. The width of the slit hole formed between the stator blades of the metal plate by the cutting process in a direction perpendicular to the extending direction is 0.2 times or more the plate thickness of the metal plate.

2. A method for manufacturing a vacuum pump, the vacuum pump comprising a first cover, a second cover, a rotor, a plurality of rotor blades, a stator, a drive unit, and a bearing. The first cover has an air intake port. The second cover has an exhaust port. The rotor is disposed in a space sealed at least by the first cover and the second cover, and has a shaft. The plurality of rotor blades are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor. The stators are arranged alternately with the rotor blades in the axial direction of the shaft. The driving unit drives the shaft to rotate. The bearing supports the shaft so that it can rotate. The method for manufacturing the vacuum pump is characterized by comprising the following steps: Cutting the metal plate, thereby integrally forming an outer peripheral edge located at an outer peripheral end of the stator, an inner peripheral edge located at an inner peripheral end of the stator, and a plurality of stator blades located between the outer peripheral edge and the inner peripheral edge, and forming a stator blade end portion as an end portion of the stator blade in a circumferential direction of the stator in a curved shape from the inner peripheral end to the outer peripheral end in such a manner that the stator blade end portion is concave in a direction away from an inclined center line of the stator blade, the inclined center line passing through a center of an inner connecting portion relative to the inner peripheral edge and a center of an outer connecting portion relative to the outer peripheral edge; The metal plate is subjected to a bending process, thereby bending the stator blade so that the inclination angle of the stator blade relative to the outer peripheral edge changes from the inner peripheral side end to the outer peripheral side end of the stator blade; The rotor blade is arranged such that an upstream ridgeline of the stator blade end portion located on the upstream side of the stator blade is a curved line from the inner peripheral side end to the outer peripheral side end of the stator blade, and the axial gap is constant with respect to a surface of the downstream side end portion of the rotor blade arranged opposite to the upstream ridgeline. The width of the slit hole formed between the stator blades of the metal plate by the cutting process in a direction perpendicular to the extending direction is 0.2 times or more the plate thickness of the metal plate.

3. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that: The radius of curvature of the corner portion of the slit hole formed in the metal plate by the cutting process is 0.2 mm or more.

4. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that: The length of the slit hole formed in the metal plate by the cutting process in the circumferential direction of the stator increases from the inner peripheral side end to the outer peripheral side end of the stator blade.

5. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that: The length of the slit hole formed in the metal plate by the cutting process in the circumferential direction of the stator is equal from the inner peripheral side end to the outer peripheral side end of the stator blade.

6. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that: The length of the slit hole formed in the metal plate by the cutting process in the circumferential direction of the stator decreases from the inner peripheral side end to the outer peripheral side end of the stator blade.

7. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that: The length of the slit hole adjacent to the outer peripheral edge formed in the metal plate by the cutting process in the radial direction of the stator is smaller than the length of the outer peripheral edge in the radial direction.

8. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that: The length of the slit hole adjacent to the inner peripheral edge formed in the metal plate by the cutting process in the radial direction of the stator is smaller than the length of the inner peripheral edge in the radial direction.

9. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that: An outer connecting portion of the stator formed on the metal plate by the cutting process and connecting the stator blade to the outer peripheral edge has a length in the radial direction of the stator smaller than a length in the radial direction of the outer peripheral edge.

10. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that: An inner connecting portion of the stator formed on the metal plate by the cutting process and connecting the stator blade to the inner peripheral edge has a length in the radial direction of the stator that is smaller than a length in the radial direction of the inner peripheral edge.

11. A vacuum pump comprising a first cover, a second cover, a rotor, a plurality of rotor blades, a stator, a driving unit, and a bearing. The first cover has an air intake port. The second cover has an exhaust port. The rotor is disposed in a space sealed at least by the first cover and the second cover, and has a shaft. The plurality of rotor blades are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor. The stators are arranged alternately with the rotor blades in the axial direction of the shaft. The driving unit drives the shaft to rotate. The bearing supports the shaft so that it can rotate. The vacuum pump is characterized in that The stator comprises an outer peripheral edge located at an outer peripheral side end of the stator, an inner peripheral edge located at an inner peripheral side end of the stator, and a plurality of stator blades located between the outer peripheral edge and the inner peripheral edge. The outer peripheral edge, the inner peripheral edge and the stator blade are integrally formed of a metal plate. The inclination angle of the stator blade relative to the outer peripheral edge changes in a curved line from the inner peripheral side end to the outer peripheral side end of the stator blade. The upstream ridgeline of the stator blade end portion located on the upstream side of the stator blade is a curved line from the inner peripheral side end to the outer peripheral side end of the stator blade, and the axial gap is constant with respect to the surface of the downstream side end portion of the rotor blade arranged opposite to the upstream ridgeline. The width of the slit hole formed between the stator blades of the metal plate by cutting in a direction perpendicular to the extending direction is 0.2 times or more the plate thickness of the metal plate.

12. A vacuum pump comprising a first cover, a second cover, a rotor, a plurality of rotor blades, a stator, a drive unit, and a bearing. The first cover has an air intake port. The second cover has an exhaust port. The rotor is disposed in a space sealed at least by the first cover and the second cover, and has a shaft. The plurality of rotor blades are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor. The stators are arranged alternately with the rotor blades in the axial direction of the shaft. The driving unit drives the shaft to rotate. The bearing supports the shaft so that it can rotate. The vacuum pump is characterized in that The stator comprises an outer peripheral edge located at an outer peripheral side end of the stator, an inner peripheral edge located at an inner peripheral side end of the stator, and a plurality of stator blades located between the outer peripheral edge and the inner peripheral edge. The outer peripheral edge, the inner peripheral edge and the stator blade are integrally formed of a metal plate. The inclination angle of the stator blade relative to the outer peripheral edge changes from the inner peripheral end to the outer peripheral end of the stator blade. The upstream ridgeline of the stator blade end portion located on the upstream side of the stator blade is a curved line from the inner peripheral side end to the outer peripheral side end of the stator blade, and the axial gap is constant with respect to the surface of the downstream side end portion of the rotor blade arranged opposite to the upstream ridgeline. The width of the slit hole between the stator wings of the metal plate formed by cutting in a direction perpendicular to the extension direction is at least 0.2 times the thickness of the metal plate in a manner such that the side end of the stator wing is formed into a concave curve in a direction away from the inclined center line of the stator wing, and the inclined center line passes through the center of the inner connecting portion relative to the inner peripheral edge and the center of the outer connecting portion relative to the outer peripheral edge.

13. A stator, wherein the stator is used for a vacuum pump, wherein the vacuum pump comprises a first cover, a second cover, a rotor, a plurality of rotor blades, a stator, a driving unit, and a bearing. The first cover has an air intake port. The second cover has an exhaust port. The rotor is disposed in a space sealed at least by the first cover and the second cover, and has a shaft. The plurality of rotor blades are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor. The stators are arranged alternately with the rotor blades in the axial direction of the shaft. The driving unit drives the shaft to rotate. The bearing supports the shaft so that it can rotate. The above-mentioned stator is characterized in that: The stator comprises an outer peripheral edge located at an outer peripheral side end of the stator, an inner peripheral edge located at an inner peripheral side end of the stator, and a plurality of stator blades located between the outer peripheral edge and the inner peripheral edge. The outer peripheral edge, the inner peripheral edge and the stator blade are integrally formed of a metal plate. The inclination angle of the stator blade relative to the outer peripheral edge changes in a curved line from the inner peripheral side end to the outer peripheral side end of the stator blade. The upstream ridgeline of the stator blade end portion located on the upstream side of the stator blade is a curved line from the inner peripheral side end to the outer peripheral side end of the stator blade, and the axial gap is constant with respect to the surface of the downstream side end portion of the rotor blade arranged opposite to the upstream ridgeline. The width of the slit hole formed between the stator blades of the metal plate by cutting in a direction perpendicular to the extending direction is 0.2 times or more the plate thickness of the metal plate.

14. A stator, wherein the stator is used for a vacuum pump, wherein the vacuum pump comprises a first cover, a second cover, a rotor, a plurality of rotor blades, a stator, a driving unit, and a bearing. The first cover has an air intake port. The second cover has an exhaust port. The rotor is disposed in a space sealed at least by the first cover and the second cover, and has a shaft. The plurality of rotor blades are fixed to the outer peripheral surface of the rotor or are formed integrally with the outer peripheral surface of the rotor. The stators are arranged alternately with the rotor blades in the axial direction of the shaft. The driving unit drives the shaft to rotate. The bearing supports the shaft so that it can rotate. The above-mentioned stator is characterized in that: The stator comprises an outer peripheral edge located at an outer peripheral side end of the stator, an inner peripheral edge located at an inner peripheral side end of the stator, and a plurality of stator blades located between the outer peripheral edge and the inner peripheral edge. The outer peripheral edge, the inner peripheral edge and the stator blade are integrally formed of a metal plate. The inclination angle of the stator blade relative to the outer peripheral edge changes from the inner peripheral end to the outer peripheral end of the stator blade. The upstream ridgeline of the stator blade end portion located on the upstream side of the stator blade is a curved line from the inner peripheral side end to the outer peripheral side end of the stator blade, and the axial gap is constant with respect to the surface of the downstream side end portion of the rotor blade arranged opposite to the upstream ridgeline. The width of the slit hole between the stator wings of the metal plate formed by cutting in a direction perpendicular to the extension direction is at least 0.2 times the thickness of the metal plate in a manner such that the side end of the stator wing is formed into a concave curve in a direction away from the inclined center line of the stator wing, and the inclined center line passes through the center of the inner connecting portion relative to the inner peripheral edge and the center of the outer connecting portion relative to the outer peripheral edge.

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