JP7502002B2 - Method for manufacturing vacuum pump, vacuum pump and stator for vacuum pump - Google Patents

Description

The present invention relates to a method for manufacturing a vacuum pump, a vacuum pump, and a stator for a vacuum pump.

In semiconductor manufacturing equipment, liquid crystal manufacturing equipment, electron microscopes, surface analysis equipment, microfabrication equipment, and the like, it is necessary to create a high degree of vacuum within the equipment. Vacuum pumps are used to create a high degree of vacuum within these devices. Vacuum pumps can maintain a high degree of vacuum within the above-mentioned equipment by rotating rotor blades relative to stator blades to exhaust gas to the outside.

For example, Patent Document 1 describes a method of forming stator blades by punching a plate-shaped disk to form stator blades arranged in the circumferential direction, and then bending the stator blades to raise them up.

JP 2006-348935 A

In the method described in Patent Document 1, the length that the stator blades rise in the axial direction (corresponding to dimension T) differs between the inner and outer circumferential sides of the stator blades. As a result, the gap between the rotor blades and stator blades aligned in the axial direction differs between the inner and outer circumferential sides. If the axial gap between the rotor blades and stator blades is large, a backflow of gas occurs between the rotor blades and stator blades, which causes a decrease in exhaust performance.

The present invention has been made to solve the above-mentioned problems, and aims to provide a method for manufacturing a vacuum pump that can improve the exhaust performance of the vacuum pump, a vacuum pump, and a stator for the vacuum pump.

One aspect of the manufacturing method of a vacuum pump according to the present invention that achieves the above object is a manufacturing method of a vacuum pump having a first casing having an intake port, a second casing having an exhaust port, a rotor arranged in a space sealed by at least the first casing and the second casing and having a shaft, a plurality of rotor blades fixed to or integrally formed on an outer circumferential surface of the rotor, a stator arranged alternately with the rotor blades in the axial direction of the shaft, a drive unit that drives and rotates the shaft, and a bearing that rotatably supports the shaft, wherein a cutting process is performed on a metal plate to integrally form an outer circumferential rim located at an outer circumferential end of the stator, an inner circumferential rim located at an inner circumferential end of the stator, and a plurality of stator blades located between the outer circumferential rim and the inner circumferential rim, and a plurality of stator blades in the circumferential direction of the stator. the step of forming a stator blade side end portion, which is an end portion of the stator blade, in a straight line from the inner peripheral end to the outer peripheral end of the stator blade; the step of bending the stator blade by bending the metal plate so that the inclination angle of the stator blade with respect to the outer peripheral rim changes in a curved line from the inner peripheral end to the outer peripheral end of the stator blade; and the step of forming an upstream ridge line of the stator blade side end portion located on the upstream side of the stator blade in a curved line from the inner peripheral end to the outer peripheral end of the stator blade, while arranging the upstream ridge line so that a gap in the axial direction is constant with respect to a surface on which the downstream end of the rotor blade is arranged, the surface facing the upstream ridge line, and the width in a direction perpendicular to the extension direction of the slit hole between the stator blades formed in the metal plate by the cutting process is 0.2 times or more the thickness of the metal plate.

Another aspect of the manufacturing method of a vacuum pump according to the present invention that achieves the above object is a manufacturing method of a vacuum pump having a first casing having an intake port, a second casing having an exhaust port, a rotor arranged in a space sealed by at least the first casing and the second casing and having a shaft, a plurality of rotor blades fixed to or integrally formed on an outer circumferential surface of the rotor, a stator arranged alternately with the rotor blades in the axial direction of the shaft, a drive unit that drives and rotates the shaft, and a bearing that rotatably supports the shaft, wherein an outer circumferential rim located at an outer circumferential end of the stator, an inner circumferential rim located at an inner circumferential end of the stator, and a plurality of stator blades located between the outer circumferential rim and the inner circumferential rim are integrally formed by cutting a metal plate, and a stator blade side end, which is an end of the stator blade in the circumferential direction of the stator, is cut from the inner circumferential end to the outer circumferential end. a step of forming the stator blade side end in a curved shape so that it is concave in a direction away from an inclination centerline passing through a center of an inner connection part of the stator blade to the inner rim and a center of an outer connection part of the stator blade to the outer rim; a step of bending the metal plate so that an inclination angle of the stator blade to the outer rim changes from the inner end to the outer end of the stator blade; and a step of forming an upstream ridgeline of the stator blade side end located on the upstream side of the stator blade so as to be curved from the inner end to the outer end of the stator blade, while arranging the upstream ridgeline so that a gap in the axial direction is constant with respect to a surface on which the downstream end of the rotor blade is disposed that faces the upstream ridgeline, wherein a width in a direction perpendicular to an extension direction of a slit hole between the stator blades formed in the metal plate by the cutting process is 0.2 times or more the thickness of the metal plate.

One aspect of the vacuum pump according to the present invention that achieves the above object is a vacuum pump comprising: a first casing having an intake port; a second casing having an exhaust port; a rotor arranged in a space sealed by at least the first casing and the second casing, the rotor having a shaft; a plurality of rotor blades fixed to or integrally formed on an outer circumferential surface of the rotor; a stator arranged alternately with the rotor blades in the axial direction of the shaft; a drive unit that drives and rotates the shaft; and a bearing that rotatably supports the shaft, the stator comprising an outer circumferential rim located at an outer circumferential end of the stator, an inner circumferential rim located at an inner circumferential end of the stator, and a bearing that rotatably supports the shaft. and a plurality of stator blades each having an outer rim, the inner rim and the stator blades being integrally formed from a metal plate, the inclination angle of the stator blades with respect to the outer rim changes in a curved manner from the inner rim to the outer rim of the stator blades, the upstream ridgeline of the stator blade end portion located on the upstream side of the stator blades is curved from the inner rim to the outer rim of the stator blades, and a gap in the axial direction is constant with respect to a surface on which the downstream end of the rotor blade facing the upstream ridgeline is located, and a width in a direction perpendicular to the extension direction of slit holes formed between the stator blades by cutting in the metal plate is 0.2 times or more the thickness of the metal plate.

Another aspect of the vacuum pump according to the present invention that achieves the above object is a vacuum pump comprising: a first casing having an intake port; a second casing having an exhaust port; a rotor arranged in a space sealed by at least the first casing and the second casing, the rotor having a shaft; a plurality of rotor blades fixed to or integrally formed on an outer circumferential surface of the rotor; a stator arranged alternately with the rotor blades in the axial direction of the shaft; a drive section that drives and rotates the shaft; and a bearing that rotatably supports the shaft, wherein the stator has an outer circumferential rim located at an outer circumferential end of the stator, an inner circumferential rim located at an inner circumferential end of the stator, and a plurality of stator blades located between the outer circumferential rim and the inner circumferential rim, and the outer circumferential rim, the inner circumferential rim and the stator blades are formed on metal plates. and the stator blades are formed integrally with the rotor blades by cutting the metal plate so that the stator blade side ends are formed in a concave curved shape away from an inclination centerline passing through a center of an inner connection part of the stator blade relative to the inner rim and a center of an outer connection part of the stator blade relative to the outer rim, the inclination angle of the stator blades with respect to the outer rim changes from an inner end to an outer end of the stator blade, the upstream ridge line of the stator blade side end located on the upstream side of the stator blade is curved from the inner end to the outer end of the stator blade, and a gap in the axial direction is constant with respect to a surface on which the downstream end of the rotor blade facing the upstream ridge line is disposed, and the width in a direction perpendicular to the extension direction of slit holes between the stator blades formed by cutting the metal plate so that the stator blade side ends are formed in a concave curved shape away from an inclination centerline passing through a center of an inner connection part of the stator blade relative to the inner rim and a center of an outer connection part of the stator blade relative to the outer rim is 0.2 times or more the thickness of the metal plate.

One aspect of a stator for a vacuum pump according to the present invention that achieves the above object is a stator for use in a vacuum pump having a first casing having an intake port, a second casing having an exhaust port, a rotor having a shaft, a plurality of rotor blades fixed to or integrally formed on an outer circumferential surface of the rotor, a stator arranged alternately with the rotor blades in the axial direction of the shaft, a drive section that drives and rotates the shaft, and a bearing that rotatably supports the shaft, wherein the stator has an outer circumferential rim located at an outer circumferential end of the stator, an inner circumferential rim located at an inner circumferential end of the stator, and a bearing that supports the shaft. and a plurality of stator blades located between a peripheral rim and a peripheral rim, the peripheral rim, the inner rim and the stator blades being integrally formed from a metal plate, the inclination angle of the stator blades with respect to the peripheral rim changing in a curved manner from the inner peripheral end to the outer peripheral end of the stator blades, the upstream ridgeline of the stator blade side end located on the upstream side of the stator blades is curved from the inner peripheral end to the outer peripheral end of the stator blades, and a gap in the axial direction is constant with respect to a surface on which the downstream end of the rotor blade facing the upstream ridgeline is located, and a width in a direction perpendicular to the extension direction of slit holes formed between the stator blades by cutting in the metal plate is 0.2 times or more the thickness of the metal plate.

Another aspect of the stator for a vacuum pump according to the present invention that achieves the above object is a stator for use in a vacuum pump having a first casing having an intake port, a second casing having an exhaust port, a rotor having a shaft, a plurality of rotor blades fixed to or integrally formed on an outer circumferential surface of the rotor, a stator arranged alternately with the rotor blades in the axial direction of the shaft, a drive unit that drives and rotates the shaft, and a bearing that rotatably supports the shaft, wherein the stator has an outer circumferential rim located at an outer circumferential end of the stator, an inner circumferential rim located at an inner circumferential end of the stator, and a plurality of stator blades located between the outer circumferential rim and the inner circumferential rim, and the outer circumferential rim, the inner circumferential rim and the stator blades are arranged in a space sealed by at least the first casing and the second casing. the rotor blades are integrally formed from a metal plate, the inclination angle of the stator blade with respect to the outer rim changes from the inner circumferential end to the outer circumferential end of the stator blade, the upstream ridge of the stator blade side end located on the upstream side of the stator blade is curved from the inner circumferential end to the outer circumferential end of the stator blade, and a gap in the axial direction is constant with respect to a surface on which the downstream end of the rotor blade facing the upstream ridge is located, and the metal plate is formed by cutting so that the stator blade side end is formed in a curved shape that is concave in a direction away from an inclination center line passing through a center of an inner connection part of the stator blade with respect to the inner rim and a center of an outer connection part of the stator blade with respect to the outer rim , and the width in a direction perpendicular to the extension direction of a slit hole between the stator blades is 0.2 times or more the thickness of the metal plate.

The manufacturing method for a vacuum pump configured as described above allows the upstream ridge of the stator blade to be positioned with a constant gap and high dimensional accuracy relative to the surface on which the downstream end of the rotor blade is positioned. This makes it possible to suppress backflow of gas and improve the exhaust performance of the vacuum pump.

The width of the slit hole formed in the metal plate by the cutting process is 0.2 times or more the thickness of the metal plate, so that the die for forming the slit hole does not become too thin, and damage to the die can be suppressed.

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 at the corners and causing damage to the stator.

The length of the slit holes formed in the metal plate by the cutting process in the circumferential direction of the stator may increase from the inner circumferential end to the outer circumferential end of the stator blade. This makes it easier to make the length of the stator blade in the circumferential direction of the stator constant from the inner circumferential end to the outer circumferential end of the stator blade. Therefore, by bending after the cutting process, the inclination angle of the stator blade with respect to the outer rim can be made constant from the inner circumferential end to the outer circumferential end, while the upstream ridge of the stator blade can be positioned so that the gap is constant with respect to the surface on which the downstream end of the rotor blade is positioned.

The length of the slit holes formed in the metal plate by the cutting process in the circumferential direction of the stator may be equal from the inner circumferential end to the outer circumferential end of the stator blade. This makes it easier to increase the length of the stator blade in the circumferential direction of the stator from the inner circumferential end to the outer circumferential end of the stator blade. Therefore, by bending after the cutting process, the inclination angle of the stator blade with respect to the outer rim can be changed from the inner circumferential end to the outer circumferential end, while the upstream ridge of the stator blade can be positioned so that the gap is constant with respect to the surface on which the downstream end of the rotor blade is positioned.

The length of the slit holes formed in the metal plate by the cutting process in the circumferential direction of the stator may become smaller from the inner circumferential end to the outer circumferential end of the stator blade. This makes it easier to increase the length of the stator blade in the circumferential direction of the stator from the inner circumferential end to the outer circumferential end of the stator blade. Therefore, by bending after the cutting process, the inclination angle of the stator blade with respect to the outer rim can be changed from the inner circumferential end to the outer circumferential end, while the upstream edge of the stator blade can be positioned so that the gap is constant with respect to the surface on which the downstream end of the rotor blade is positioned. In addition, since the length of the slit holes in the circumferential direction changes, it is possible to prevent the mold for forming the slit holes from becoming thin as a whole, and to prevent damage to the mold.

The length of the slit hole adjacent to the outer peripheral rim formed in the metal plate by the cutting process in the radial direction of the stator may be smaller than the length of the outer peripheral rim in the radial direction. This makes it easier to secure a portion to be clamped by a die radially outward of the slit hole in the cutting process to form the slit hole. This allows the slit hole to be appropriately formed in the stator in the cutting process.

The length of the slit hole adjacent to the inner rim formed in the metal plate by the cutting process in the radial direction of the stator may be smaller than the length of the inner rim in the radial direction. This makes it easier to secure a portion to be clamped by a die radially inward from the slit hole in the cutting process to form the slit hole. Therefore, the slit hole can be appropriately formed in the stator in the cutting process.

The length of the outer connecting portion that connects the stator blades of the stator formed on the metal plate by the cutting process to the outer peripheral rim in the radial direction of the stator may be smaller than the length of the outer peripheral rim in the radial direction. This makes it easier to secure the area to be clamped by a die in the cutting process to form the slit holes. Therefore, the slit holes can be appropriately formed in the stator in the cutting process. Also, since the outer connecting portion does not become too long, it is easy to secure the radial length of the stator blades. This makes it possible to improve the exhaust performance of the vacuum pump.

The length of the inner connecting portion that connects the stator blades and the inner rim of the stator formed on the metal plate by the cutting process in the radial direction of the stator may be smaller than the length of the inner rim in the radial direction. This makes it easier to secure the area to be clamped by a mold in the cutting process to form the slit holes. Therefore, the slit holes can be appropriately formed in the stator in the cutting process. Also, since the inner connecting portion is not too long, it is easy to secure the radial length of the stator blades. This improves the exhaust performance of the vacuum pump.

In a vacuum pump configured as described above, the upstream ridge of the stator blade is positioned with a constant gap and high dimensional accuracy relative to the surface on which the downstream end of the rotor blade is positioned. This makes it possible to suppress backflow of gas and improve the exhaust performance of the vacuum pump.

When the stator for a vacuum pump configured as described above is incorporated into a vacuum pump, the upstream ridge of the stator blades can be positioned with a constant gap and high dimensional accuracy relative to the surface on which the downstream ends of the rotor blades are positioned. This makes it possible to suppress backflow of gas and improve the exhaust performance of the vacuum pump.

1 is a cross-sectional view showing a vacuum pump according to a first embodiment. FIG. FIG. 2 is an enlarged perspective view of a portion of the stator. FIG. 2 is a plan view showing a metal plate before cutting. 5A and 5B are diagrams for explaining the manufacturing process of the stator, in which (A) is a plan view after cutting, and (B) is a plan view after bending. 5A is a side view taken along the line A in FIG. 5B; FIG. 5B is a side view taken along the line B in FIG. 5B; and FIG. 5C is a front view taken along the line C in FIG. 5B. FIG. 2 is a diagram showing the arrangement of stator blades and rotor blades in a vacuum pump in which the stator is incorporated. 10A and 10B are diagrams illustrating a manufacturing process of a stator of a vacuum pump according to a second embodiment, in which (A) is a plan view after cutting, and (B) is a plan view after bending. 8A and 8B are diagrams showing a portion of a stator after bending processing, in which (A) is a side view seen from the arrow A in FIG. 8B, (B) is a side view seen from the arrow B in FIG. 8B, and (C) is a front view seen from the arrow C in FIG. 8B. 10A and 10B are diagrams illustrating a manufacturing process of a stator of a vacuum pump according to a third embodiment, in which (A) is a plan view after cutting, and (B) is a plan view after bending. 10A is a side view taken along the line A in FIG. 10B; FIG. 10B is a side view taken along the line B in FIG. 10B; and FIG. 10C is a front view taken along the line C in FIG. 10B. 10A and 10B are diagrams illustrating a manufacturing process of a stator of a vacuum pump according to a fourth embodiment, in which (A) is a plan view after cutting, and (B) is a plan view after bending. 13A and 13B are plan views showing modified examples of the stator in the fourth embodiment after cutting, in which FIG. 13A shows a first modified example, and FIG. 13B shows a second modified example.

The following describes an embodiment of the present invention with reference to the drawings. Note that the dimensions in the drawings may be exaggerated for the sake of explanation and may differ from the actual dimensions. In addition, in this specification and the drawings, components that have substantially the same functional configuration are given the same reference numerals to avoid redundant explanation.

<First embodiment>

As shown in FIG. 1, the vacuum pump 1 according to the first embodiment of the present invention is a turbomolecular pump that exhausts gas by ejecting gas molecules as a rotor 30 equipped with rotor blades 32 rotates at high speed. The vacuum pump 1 has a vacuum pump main body 2 for sucking in and exhausting gas, and a control device 3 for controlling the vacuum pump main body 2.

The vacuum pump body 2 sucks and exhausts gas from a chamber of, for example, a semiconductor manufacturing device. The vacuum pump body 2 has a cylindrical first casing 10 in which an intake port 11 is formed, a second casing 20 in which an exhaust port 21 is formed, a stator column 22 fixed to the second casing 20, a stationary blade section 40, and a threaded spacer 90. Furthermore, the vacuum pump body 2 has a rotating rotor 30, a bearing that rotatably supports the rotor 30, a displacement sensor that detects the displacement of the rotor 30, and a motor 80 (drive section) that rotates and drives the rotor 30.

The first casing 10 is located at the top of the vacuum pump body 2, and has an intake port 11 formed at its upper end. The first casing 10 is fixed to the second casing 20 disposed at its bottom by bolts 12.

The rotor 30 is rotatably arranged inside the first casing 10. The rotor 30 has a shaft 35, multiple stages of rotor blades 32 in the axial direction, and a cylindrical portion 33 arranged downstream of the rotor blades 32. The rotor blades 32 constitute a turbomolecular pump and are blades for sucking and exhausting gas. The multiple rotor blades 32 in each stage are arranged radially in the circumferential direction.

The rotor 30 is generally cylindrical, with the shaft 35 passing through and fixed to the inside. Each rotor blade 32 is formed at a predetermined angle from a plane perpendicular to the axial direction of the shaft 35 in order to transport exhaust gas molecules downward by collision. The rotor blades 32 are integrally formed on the outer circumferential surface of the rotor 30. Alternatively, the rotor blades 32 may be fixed to the outer circumferential surface of the rotor 30.

The cylindrical portion 33 is disposed downstream of the rotor blades 32 and is formed in a cylindrical shape. This cylindrical portion 33 is formed to protrude toward the inner peripheral surface of the threaded spacer 90. The cylindrical portion 33 is adjacent to the inner peripheral surface of the threaded spacer 90 with a predetermined gap therebetween.

The shaft 35 is disposed at the center of rotation of the rotor 30. The shaft 35 has a cylindrical main shaft portion 36 and a circular disk 37 disposed below the main shaft portion 36. The main shaft portion 36 and the disk 37 are formed of a highly magnetically permeable material (iron, etc.) that can be attracted by magnetism. The main shaft portion 36 is attracted and its position is controlled by the magnetic forces of an upstream radial electromagnet 61 and a downstream radial electromagnet 62, which will be described later.

The bearing is, for example, a so-called five-axis controlled magnetic bearing, which supports and levitates the shaft 35 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 comes into contact with the main shaft portion 36 when the axial runout of the rotor 30 becomes large, preventing the rotor 30 from coming into direct contact with the stator side and being damaged.

The upstream radial electromagnet 61 has four electromagnets arranged in pairs on each of two axes that are orthogonal to the plane perpendicular to the rotation axis. The downstream radial electromagnet 62 has four electromagnets arranged in pairs on each of two axes that are orthogonal to the plane perpendicular to the rotation axis. The axial electromagnets 63A and 63B are arranged above and below the disk 37.

The displacement sensor is disposed on the stator column 22 to detect the displacement of the rotor 30. The displacement sensor has an upstream radial sensor 71, a downstream radial sensor 72, and an axial sensor 73. The upstream radial sensor 71 is four non-contact sensors disposed in close proximity 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 the displacement signal to the control device 3. Examples of sensors used as the upstream radial sensor 71 include an inductance sensor and an eddy current sensor.

The downstream radial sensors 72 are four non-contact sensors arranged in close proximity to and corresponding to the four downstream radial electromagnets 62. The downstream radial sensors 72 are configured to detect radial displacement of the lower part of the main shaft portion 36 and transmit the displacement signal to the control device 3. Examples of sensors used as the downstream radial sensors 72 include inductance sensors and eddy current sensors.

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

Based on the displacement signal detected by the upstream radial sensor 71, the control device 3 controls the excitation of the upstream radial electromagnet 61 via a compensation circuit having a PID adjustment function, and adjusts the upstream radial position of the main shaft portion 36. This adjustment is performed independently for each of the two axes that are orthogonal to the plane perpendicular to the rotation axis.

The control device 3 also 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, and adjusts the downstream radial position of the main shaft portion 36. This adjustment is performed independently for each of the two axes that are perpendicular to the plane perpendicular to the rotation axis.

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 upwards by magnetic force, and the axial electromagnet 63B attracts the disk 37 downwards. In this way, by appropriately adjusting the magnetic force exerted on the shaft 35, the magnetic bearing can magnetically levitate the shaft 35 and support it rotatably without contact.

The motor 80 has magnetic poles 81, which are multiple permanent magnets arranged on the rotor side, and a motor electromagnet 82 arranged on the stator side. A torque component that rotates the shaft 35 is applied to the magnetic poles 81 from the motor electromagnet 82. This causes the rotor 30 to rotate.

The motor 80 is also fitted with a rotation speed sensor and a motor temperature sensor (not shown). The rotation speed sensor and the motor temperature sensor transmit their detection results as detection signals to the control device 3. 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.

The stationary blade section 40 has multiple stages of stators 41 and multiple stator spacers 42 stacked so that each stage of the stator 41 is sandwiched between them. Each stator 41 has multiple stator blades 43.

The stator blades 43, like the rotor blades 32, are formed at a predetermined angle from a plane perpendicular to the axial direction of the shaft 35. The stator blades 43 are arranged inward of the first casing 10, staggered with the rotor blades 32. The outer peripheral end of the stator blades 43 is supported by being sandwiched between a plurality of stacked ring-shaped stator spacers 42. The stator spacers 42 are stacked inside the first casing 10. The stator spacers 42 are made of metals such as aluminum, iron, stainless steel, copper, etc., or alloys containing these metals as components.

The threaded spacer 90 is disposed between the lower part of the stator spacer 42 and the second casing 20. The threaded spacer 90 is adjacent to the cylindrical portion 33 of the rotor 30, which is disposed in a cylindrical shape, with a predetermined gap therebetween. A plurality of helical thread grooves 91 are formed on the inner peripheral surface of the threaded spacer 90. The helical direction of the thread grooves 91 is the direction in which the molecules of the exhaust gas are transported toward the exhaust port 21 when they move in 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.

The second casing 20 is a disk-shaped member that constitutes the bottom of the vacuum pump body 2. The second casing 20 has an exhaust port 21 formed at the bottom of the threaded spacer 90. The exhaust port 21 is connected to the outside. The second casing 20 is generally made of a metal such as iron, aluminum, or stainless steel. The second casing 20 preferably not only physically holds the vacuum pump body 2, but also functions as a heat conduction path. Therefore, the material that constitutes the second casing 20 is preferably a metal that is rigid and has high thermal conductivity, and for example, iron, aluminum, copper, etc. can be suitably used.

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. As a result, exhaust gas from the chamber is sucked in through the intake port 11 by the action of the rotor blades 32 and the stator blades 43.

The exhaust gas sucked in from the intake port 11 is transferred to the second casing 20 by the rotor blades 32 and the stator blades 43. At this time, the temperature of the rotor blades 32 rises due to frictional heat generated when the exhaust gas comes into contact with the rotor blades 32 and conduction of heat generated by the motor 80. However, this heat is transferred to the stator blades 43 side by radiation or conduction by gas molecules of the exhaust gas. Furthermore, the stator spacers 42 are joined to each other at the outer periphery. Therefore, the heat received by the stator blades 43 from the rotor blades 32 and frictional heat generated when the exhaust gas comes into contact with the stator blades 43 are transferred to the outside via the stator spacers 42.

In addition, the exhaust gas transferred to the second casing 20 is transferred to the exhaust port 21 while being guided by the thread groove 91 of the threaded spacer 90 .
In this 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 circumferential surface of the threaded spacer 90. However, conversely, a thread groove may be formed on the outer circumferential surface of the cylindrical portion 33, and a spacer having a cylindrical inner circumferential surface may be disposed around it.

The outer periphery of the electrical equipment is covered with a stator column 22 so that the gas sucked in from the intake port 11 does not enter the electrical equipment side, which is composed of the motor 80, downstream radial electromagnet 62, downstream radial sensor 72, upstream radial electromagnet 61, upstream radial sensor 71, etc. The inside of the stator column 22 surrounding the electrical equipment is kept at a predetermined pressure by purge gas. The second casing 20 is provided with piping (not shown), through which purge gas is introduced. The introduced purge gas is sent to the exhaust port 21 through the gaps between the auxiliary bearing 65 and the shaft 35, between the motor 80, and between the stator column 22 and the rotor blades 32.

A heater (not shown) and an annular water-cooled tube 23 are wound around the outer periphery of the second casing 20, etc. Also, a temperature sensor (e.g., a thermistor) (not shown) is embedded in the second casing 20. Based on the signal from this temperature sensor, the heating of the heater and the cooling by the water-cooled tube 23 are controlled so as to keep the temperature of the second casing 20 at a constant high temperature (set temperature). This prevents the process gas from adhering and accumulating inside the vacuum pump main body 2.

Process gases are sometimes introduced into the chamber at high temperatures to increase their reactivity. When these process gases are cooled and cooled to a certain temperature as they are exhausted, they become solid and may precipitate products in the exhaust system. When this type of process gas cools down inside the vacuum pump body 2, it becomes solid and adheres to and accumulates inside the vacuum pump body 2.

For example, when SiCl ₄ is used as a process gas in an Al etching device, solid products (e.g., AlCl ₃ ) precipitate and accumulate inside the vacuum pump body 2 at low vacuum (1×10 ⁵ [Pa] to 1 [Pa]) and low temperature (about 20° C.). When the precipitates of the process gas accumulate inside the vacuum pump body 2, the deposits narrow the pump flow path, causing a decrease in the performance of the vacuum pump body 2. For example, the above-mentioned products tend to solidify and adhere to low-temperature parts near the exhaust port 21, particularly near the cylindrical part 33 and the threaded spacer 90. Therefore, the control device 3 controls the heating of the heater and the cooling by the water cooling tube 23 based on the signal from the temperature sensor so as to keep the temperature of the second casing 20 at a constant high temperature (set temperature). This makes it possible to suppress the process gas from adhering and accumulating inside the vacuum pump body 2.

At least one stator 41 has two split stators 41A formed by dividing a ring shape into two at 180 degrees so that they can be inserted from the outside in the radial direction between the rotor blades 32 arranged in the axial direction, as shown in FIG. 2. The split stator 41A is formed by cutting and bending a single metal plate. The cutting is a shearing process using a die and a punch. The cutting and bending may be performed separately or simultaneously. It is preferable that the cutting and bending are performed continuously while feeding the metal plate using a progressive press die. As shown in FIGS. 2 and 3, the split stator 41A has an inner rim 44 located on the inner periphery side, an outer rim 45 located on the outer periphery side, a plurality of stator blades 43 arranged between the inner rim 44 and the outer rim 45, an inner connecting portion 46 connecting the stator blades 43 and the inner periphery rim 44, and an outer connecting portion 47 connecting the stator blades 43 and the outer periphery rim 45. The inner connecting portion 46 and the outer connecting portion 47 are formed shorter than the stator blades 43 in the circumferential direction of the stator 41. Between the stator blades 43 arranged in the circumferential direction, slit holes 48 are formed by punching by cutting. Aluminum or the like can be suitably used as the material of the metal plate constituting the stator 41. The slit holes 48 have an outer slit 48A extending in the circumferential direction on the inner peripheral side of the outer peripheral rim 45, an inner slit 48B extending in the circumferential direction on the outer peripheral side of the inner peripheral rim 44, and a central slit 48C extending between the outer slit 48A and the inner slit 48B. The central slit 48C connects the center of the outer slit 48A in the circumferential direction of the stator 41 with the center 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 the direction perpendicular to the extending direction.

Next, the manufacturing process of the stator 41 will be described. First, as shown in FIG. 4, a half-ring-shaped metal plate is prepared as a material. The half-ring-shaped metal plate may be formed by cutting, but the processing method is not particularly limited. Next, the portion indicated by the dashed line is cut by cutting using a die. As a result, as shown in FIG. 5(A), a slit hole 48 is formed between the stator blades 43 arranged in the circumferential direction. The slit hole 48 has an outer end 49 which is the end on the inner circumferential side of the outer rim 45, an inner end 50 which is the end on the outer circumferential side of the inner rim 44, two outer connection ends 51 which are the ends of the outer connecting portion 47 in the circumferential direction, two inner connection ends 52 which are the ends of the inner connecting portion 46 in the circumferential direction, and two stator blade ends 53 which are the ends of the stator blades 43. Each stator blade end 53 has a stator blade outer end 53A located on the outer periphery of the stator blade 43, a stator blade inner end 53B located on the inner periphery of the stator blade 43, and a stator blade side end 53C extending in the radial direction of the stator 41 between the stator blade outer end 53A and the stator blade inner end 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, even more preferably 0.7 times or more, and even more preferably 1 time or more, of the thickness of the metal plate. This prevents the die for cutting out the slit hole 48 from becoming too thin, and prevents damage to the die.

A first corner C1 is formed between the outer end 49 and the outer connection end 51. The corner is a portion where the wall surface constituting the slit hole 48 forms a recess. A second corner C2 is formed between the outer connection end 51 and the stator blade outer end 53A. A third corner C3 is formed between the stator blade inner end 53B and the inner connection end 52. A fourth corner C4 is formed between the inner end 50 and the inner connection end 52. The first corner C1, the second corner C2, the third corner C3, and the fourth corner C4 are preferably formed by curved surfaces. The curvature radius of the first corner C1, the second corner C2, the third corner C3, and the fourth corner C4 is preferably 0.2 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more. This makes it possible to suppress stress concentration at each corner and damage to the stator 41.

A first corner E1 is formed at the joint between the stator blade outer end 53A and the stator blade side end 53C. The corner is a portion where the wall surface constituting the slit hole 48 forms a convex portion. A second corner E2 is formed at the joint between the stator blade inner end 53B and the stator blade side end 53C. It is preferable that the first corner E1 and the second corner E2 are formed as sharp corners without curvature. This makes it possible to prevent the gap between the stator blade outer end 53A and the rotor blade 32 from becoming large, and to prevent a decrease in exhaust efficiency. The first corner E1 and the second corner E2 may be formed with a radius of curvature.

The two stator blade side ends 53C arranged on each stator blade 43 are formed as straight lines when viewed from the out-of-plane direction of the metal plate, and are parallel to each other. 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 part 46 in the circumferential direction and the center of the outer connecting part 47 in the circumferential direction is 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.

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 side to the outer side of the stator blade 43.

It is preferable that the length L3 of the slit hole 48 adjacent to the outer peripheral rim 45 in the radial direction of the stator 41 is smaller than the length L2 of the outer peripheral rim 45 in the radial direction. Therefore, in the cutting process for forming the slit hole 48, a sufficient area to be clamped by the die can be secured radially outward from the slit hole 48. Note that if a sufficient area to be clamped by the die cannot be secured, it may be difficult to form the slit hole 48. Therefore, the slit hole 48 (particularly the outer slit 48A adjacent to the outer peripheral rim 45) can be appropriately formed in the stator 41 in the cutting process.

In addition, it is preferable that the length L4 of the slit hole 48 adjacent to the inner rim 44 in the radial direction of the stator 41 is smaller than the length L5 of the inner rim 44 in the radial direction. Therefore, in the cutting process for forming the slit hole 48, a sufficient area to be clamped by the die can be secured radially inward from the slit hole 48. Note that if a sufficient area to be clamped by the die cannot be secured, it may be difficult to form the slit hole 48. Therefore, the slit hole 48 (particularly the inner slit 48B adjacent to the inner rim 44) can be appropriately formed in the stator 41 in the cutting process.

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 rim 45 in the radial direction. This ensures that there is a sufficient area to be clamped by a die during the cutting process to form the slit holes 48. This allows the slit holes 48 to be properly formed in the stator 41 during the cutting process. In addition, because the outer connecting portion 47 is not too long, the radial length of the stator blades 43 can be sufficiently ensured. This improves the exhaust performance of the vacuum pump 1.

In addition, it is preferable that the length L7 of the inner connecting portion 46 in the radial direction of the stator 41 is smaller than the length L5 of the inner rim 44 in the radial direction. This ensures that there is a sufficient area to be clamped by a die in the cutting process to form the slit holes 48. This allows the slit holes 48 to be properly formed in the stator 41 in the cutting process. In addition, because the inner connecting portion 46 is not too long, the radial length of the stator blades 43 can be sufficiently ensured. This improves the exhaust performance of the vacuum pump 1.

After forming the slit holes 48 in the metal plate, the metal plate is subjected to bending processing using a die. As a result, as shown in Figures 5 (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 blades 43 are tilted relative to the outer rim 45 and the inner rim 44. The tilt angle θ of the stator blades 43 relative to the outer rim 45 is constant from the outer periphery to the inner periphery of the stator blades 43. Note that the tilt angle θ at the portion of the stator blades 43 connected to the outer connecting portion 47 and the inner connecting portion 46 may differ slightly from the constant tilt angle θ due to the influence of the twisting of the outer connecting portion 47 and the inner connecting portion 46.

After this, the stator 41 is assembled into the vacuum pump 1 as shown in FIG. 7. Since the stator blades 43 are inclined with respect to the outer rim 45, the upstream ridge 54 is formed at the stator blade end 53C located upstream of the outer rim 45 at a position far from the surface on which the outer rim 45 is located. The ridge is formed at the boundary between the wall surface of the slit hole 48 and the surface of the metal plate. The upstream ridge 54 is disposed at a constant height H upstream from the outer rim 45 and the inner rim 44. The upstream ridge 54 is disposed at a constant gap S in the axial direction with respect to the rotor blade lower reference plane P1 on which the downstream end of the rotor blade 32 facing the upstream side is located. In other words, the entire upstream ridge 54 is disposed at an appropriate gap S with high dimensional accuracy with respect to the rotor blade 32. As a result, gas backflow is less likely to occur between the stator blades 43 and the rotor blades 32, and the exhaust performance of the vacuum pump 1 can be improved. In addition, when the stator blade 43 is inclined, a downstream ridge 55 is formed at a position far from the surface on which the outer rim 45 is located at the stator blade side end 53C located downstream of the outer rim 45. The downstream ridge 55 is disposed at a constant height H downstream from the outer rim 45 and the inner rim 44. The height H of the upstream ridge 54 and the height H of the downstream ridge 55 may be the same or different. The downstream ridge 55 is disposed at a constant gap S in the axial direction with respect to the rotor blade upper reference plane P2 on which the upstream end of the rotor blade 32 facing downstream is located. In other words, the entire downstream ridge 55 is disposed at an appropriate gap S with high dimensional accuracy with respect to the rotor blade 32. As a result, gas backflow is less likely to occur between the stator blade 43 and the rotor blade 32, and the exhaust performance of the vacuum pump 1 can be improved.

<Second embodiment>

As shown in Figures 8 and 9, the vacuum pump 1 according to the second embodiment differs from the first embodiment only in the shape of the slit holes 48 and the stator blades 43 of the stator 41. In the second embodiment, when cutting the metal plate, as shown in Figure 8 (A), the two stator blade side ends 53C of the slit holes 48 are formed to be parallel straight lines when viewed from the outside of the plane 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.

After forming the slit holes 48 in the metal plate, the metal plate is subjected to bending processing using a die. As a result, as shown in Figures 8 (B) and 9, the outer connecting part 47 and the inner connecting part 46 are twisted around the inclination center line X, and the stator blade 43 is inclined relative to the outer rim 45 and the inner rim 44. The upstream ridge 54 of the stator blade side end 53C is disposed at a constant height H upstream from the outer rim 45 and the inner rim 44. The upstream ridge 54 is formed by a curve (see Figure 8 (B)). When the stator 41 is assembled into the vacuum pump 1, the upstream ridge 54 is disposed at a constant gap S in the axial direction with respect to the rotor blade lower reference plane P1 (see Figure 7) on which the downstream end of the rotor blade 32 facing the upstream side is located. In other words, the entire upstream ridge 54 is disposed at an appropriate gap S with high dimensional accuracy with respect to the rotor blade 32. Therefore, gas backflow is less likely to occur between the stator blades 43 and the rotor blades 32, improving the exhaust performance of the vacuum pump 1. 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 rim 45 gradually increases from the outer periphery side to the inner periphery side of the stator blade 43. That is, the inclination angle θ is larger on the inner periphery side where the distance from the inclination center line X to the stator blade side end 53C is shorter. Therefore, as shown in FIG. 9, the inclination angle θ1 at the inner periphery end of the stator blade side end 53C is larger than the inclination angle θ2 at the outer periphery end of the stator blade side end 53C. It is considered that the inclination angle θ at this time changes in direct proportion to a linear function or in a curved manner with respect to the radial direction.

The downstream ridge 55 of the stator blade end 53C is disposed at a constant height H downstream from the outer rim 45 and the inner rim 44. The downstream ridge 55 is formed by a curve (see FIG. 8B). The downstream ridge 55 is disposed at a constant gap S in the axial direction with respect to the rotor blade upper reference plane P2 (see FIG. 7) on which the upstream end of the rotor blade 32 facing downstream is located. That is, the entire downstream ridge 55 is disposed at an appropriate gap S with high dimensional accuracy with respect to the rotor blade 32. This makes it difficult for gas to flow back between the stator blade 43 and the rotor blade 32, improving the exhaust performance of the vacuum pump 1.

<Third embodiment>

As shown in Figures 10 and 11, the vacuum pump 1 according to the third embodiment differs from the first embodiment only in the shape of the slit holes 48 of the stator 41 and the stator blades 43. In the third embodiment, when cutting the metal plate, as shown in Figure 10 (A), the length W between two adjacent stator blade side ends 53C in the circumferential direction of the stator 41 in each slit hole 48 is processed so as to decrease 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.

After forming the slit holes 48 in the metal plate, the metal plate is subjected to bending processing using a die. As a result, as shown in Figures 10 (B) and 11, the outer connecting part 47 and the inner connecting part 46 are twisted around the inclination center line X, and the stator blade 43 is inclined relative to the outer rim 45 and the inner rim 44. The upstream ridge 54 of the stator blade side end 53C is disposed at a constant height H upstream from the outer rim 45 and the inner rim 44. The upstream ridge 54 is formed by a curve (see Figure 10 (B)). When the stator 41 is assembled into the vacuum pump 1, the upstream ridge 54 is disposed at a constant gap S in the axial direction with respect to the rotor blade lower reference plane P1 (see Figure 7) on which the downstream end of the rotor blade 32 facing the upstream side is located. In other words, the entire upstream ridge 54 is disposed at an appropriate gap S with high dimensional accuracy with respect to the rotor blade 32. Therefore, gas backflow is less likely to occur between the stator blades 43 and the rotor blades 32, improving the exhaust performance of the vacuum pump 1. 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 rim 45 gradually increases from the outer periphery side to the inner periphery side of the stator blade 43. That is, the inclination angle θ is larger on the inner periphery side, where the distance from the inclination center line X to the stator blade side end 53C is shorter. Therefore, as shown in FIG. 11, the inclination angle θ1 at the inner periphery end of the stator blade side end 53C is larger than the inclination angle θ2 at the outer periphery end of the stator blade side end 53C. It is considered that the inclination angle θ at this time changes in direct proportion to a linear function or in a curved manner with respect to the radial direction.

The downstream ridge 55 of the stator blade end 53C is disposed at a constant height H downstream from the outer rim 45 and the inner rim 44. The downstream ridge 55 is formed by a curve (see FIG. 10B). The downstream ridge 55 is disposed at a constant gap S in the axial direction with respect to the rotor blade upper reference plane P2 (see FIG. 7) on which the upstream end of the rotor blade 32 facing downstream is located. That is, the entire downstream ridge 55 is disposed at an appropriate gap S with high dimensional accuracy with respect to the rotor blade 32. This makes it difficult for gas to flow back between the stator blade 43 and the rotor blade 32, improving the exhaust performance of the vacuum pump 1.

<Fourth embodiment>

As shown in FIG. 12, the vacuum pump 1 according to the fourth embodiment differs from the first embodiment only in the shape of the slit hole 48 and the stator blade 43 of the stator 41. In the fourth embodiment, when cutting the metal plate, as shown in FIG. 12(A), the two stator blade side ends 53C of the slit hole 48 are formed to be curved when viewed from the out-of-plane direction of the metal plate. In each slit hole 48, the length W between two adjacent stator blade side ends 53C in the circumferential direction of the stator 41 changes from the inner periphery side to the outer periphery side of the stator blade 43. In addition, the distance L1 from the inclined center line X to the stator blade side end 53C changes from the inner periphery side to the outer periphery side of the stator blade 43. The stator blade side end 53C is a curve that is concave in the direction away from the inclined center line X. Note that the stator blade side end 53C may be a curve that is convex in the direction away from the inclined center line X, as in the first modified example of the fourth embodiment shown in FIG. 13(A). Also, as in the second modified example of the fourth embodiment shown in FIG. 13B, one of the two stator blade side ends 53C that form the slit hole 48 may be a curve that is concave in the direction away from the tilt center line X, and the other may be a curve that is convex in the direction away from the tilt center line X. The two curved stator blade side ends 53C that form the slit hole 48 may or may not be parallel.

In the fourth embodiment, after forming slit holes 48 in the metal plate as shown in Figs. 12(A) and 13, as shown in Fig. 12(B), the metal plate is subjected to bending processing using a die. As a result, the outer connecting portion 47 and the inner connecting portion 46 are twisted around the inclination center line X, and the stator blade 43 is inclined relative to the outer rim 45 and the inner rim 44. The upstream ridge 54 of the stator blade side end portion 53C is disposed at a constant height H upstream from the outer rim 45 and the inner rim 44. The upstream ridge 54 is formed by a curve. Note that a part or all of the upstream ridge 54 may be formed by a straight line. When the stator 41 is assembled in the vacuum pump 1, the upstream ridge 54 is disposed at a constant gap S in the axial direction with respect to the rotor blade lower reference plane P1 (see Fig. 7) on which the downstream end of the rotor blade 32 facing the upstream side is located. That is, the entire upstream ridge 54 is disposed at an appropriate gap S with high dimensional accuracy with respect to the rotor blade 32. This makes it difficult for gas to flow back between the stator blades 43 and the rotor blades 32, improving the exhaust performance of the vacuum pump 1. To form such a stator blade side end 53C, the inclination angle θ of the stator blades 43 relative to the outer rim 45 changes from the outer periphery side to the inner periphery side of the stator blades 43.

The downstream ridge 55 of the stator blade end 53C is disposed at a constant height H downstream from the outer rim 45 and the inner rim 44. The downstream ridge 55 is formed by a curve. Note that a part or all of the downstream ridge 55 may be formed by a straight line. The downstream ridge 55 is disposed at a constant gap S in the axial direction with respect to the rotor blade upper reference plane P2 (see FIG. 7) on which the upstream end of the rotor blade 32 facing downstream is located. That is, the entire downstream ridge 55 is disposed at an appropriate gap S with high dimensional accuracy with respect to the rotor blade 32. This makes it difficult for gas to flow back between the stator blade 43 and the rotor blade 32, improving the exhaust performance of the vacuum pump 1.

The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical concept of the present invention. For example, the bearing does not have to be a magnetic bearing. Also, in the above-described embodiment, the stator blades 43 have a portion located upstream of the outer rim 45 and a portion located downstream, but they do not have to have a portion located downstream.

REFERENCE SIGNS LIST 1 Vacuum pump 2 Vacuum pump body 10 First casing 11 Intake port 20 Second casing 21 Exhaust port 30 Rotor 32 Rotor blade 40 Stationary blade portion 41 Stator 41A Split stator 43 Stator blade 44 Inner peripheral rim 45 Outer peripheral rim 46 Inner connecting portion 47 Outer connecting portion 48 Slit hole 49 Outer end portion 50 Inner end portion 51 Outer connecting end portion 52 Inner connecting end portion 53 Stator blade end portion 53A Stator blade outer end portion 53B Stator blade inner end portion 53C Stator blade side end portion 54 Upstream side ridge line 55 Downstream side ridge line 80 Motor (drive portion)
C1 First corner C2 Second corner C3 Third corner C4 Fourth corner E1 First corner E2 Second corner P1 Rotor blade lower reference plane P2 Rotor blade upper reference plane θ Tilt angle

Claims (14)

A first casing having an intake port;
a second casing having an exhaust port;
a rotor having a shaft and disposed in a space sealed by at least the first casing and the second casing;
A plurality of rotor blades fixed to or integrally formed on an outer peripheral surface of the rotor;
a stator arranged alternately with the rotor blades in the axial direction of the shaft;
A drive unit that rotates the shaft;
and a bearing that rotatably supports the shaft.
a cutting process is performed on a metal plate to integrally form an outer circumferential rim located at an outer circumferential end of the stator, an inner circumferential rim located at an inner circumferential end of the stator, and a plurality of stator blades located between the outer circumferential rim and the inner circumferential rim, and form stator blade side ends, which are ends of the stator blades in the circumferential direction of the stator, in a straight line from the inner circumferential end to the outer circumferential end of the stator blade;
bending the stator blades by bending the metal plate such that an inclination angle of the stator blades with respect to the outer rim changes in a curved manner from an inner circumferential end to an outer circumferential end of the stator blades;
and forming an upstream edge of the stator blade end portion located on the upstream side of the stator blade into a curved line extending from an inner peripheral end to an outer peripheral end of the stator blade, and disposing the upstream edge and a surface on which the downstream end portion of the rotor blade is disposed, such that a gap in the axial direction is constant;
a width of the slit holes between the stator blades formed in the metal plate by the cutting process in a direction perpendicular to the extension direction of the slit holes is 0.2 times or more a thickness of the metal plate. A first casing having an intake port;
a second casing having an exhaust port;
a rotor having a shaft and disposed in a space sealed by at least the first casing and the second casing;
A plurality of rotor blades fixed to or integrally formed on an outer peripheral surface of the rotor;
a stator arranged alternately with the rotor blades in the axial direction of the shaft;
A drive unit that rotates the shaft;
and a bearing that rotatably supports the shaft.
cutting a metal plate to integrally form an outer rim located at an outer circumferential end of the stator, an inner rim located at an inner circumferential end of the stator, and a plurality of stator blades located between the outer rim and the inner rim, and forming stator blade side ends, which are ends of the stator blades in the circumferential direction of the stator , in a curved shape such that the stator blade side ends become concave from the inner circumferential end to the outer circumferential end in a direction away from an inclined center line that passes through a center of an inner connection portion of the stator blade to the inner rim and a center of an outer connection portion of the stator blade to the outer circumferential rim;
bending the stator blades by bending the metal plate such that an inclination angle of the stator blades with respect to the outer rim changes from an inner circumferential end to an outer circumferential end of the stator blades;
and forming an upstream edge of the stator blade end portion located on the upstream side of the stator blade into a curved line extending from an inner peripheral end to an outer peripheral end of the stator blade, and disposing the upstream edge and a surface on which the downstream end portion of the rotor blade is disposed, such that a gap in the axial direction is constant;
a width of the slit holes between the stator blades formed in the metal plate by the cutting process in a direction perpendicular to the extension direction of the slit holes is 0.2 times or more a thickness of the metal plate. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that the radius of curvature of the corners of the slit holes formed in the metal plate by the cutting process is 0.2 mm or more. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that the length of the slit holes formed in the metal plate by the cutting process in the circumferential direction of the stator increases from the inner end to the outer end of the stator blade. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that the length of the slit holes formed in the metal plate by the cutting process in the circumferential direction of the stator is equal from the inner end to the outer end of the stator blade. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that the length of the slit holes formed in the metal plate by the cutting process in the circumferential direction of the stator becomes smaller from the inner end to the outer end of the stator blade. 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 rim formed in the metal plate by the cutting process in the radial direction of the stator is smaller than the length of the outer rim in the radial direction. 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 rim formed in the metal plate by the cutting process in the radial direction of the stator is smaller than the length of the inner rim in the radial direction. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that the length of the outer connecting portion that connects the stator blades of the stator formed in the metal plate by the cutting process to the outer peripheral rim in the radial direction of the stator is smaller than the length of the outer peripheral rim in the radial direction. The method for manufacturing a vacuum pump according to claim 1 or 2, characterized in that the length of the inner connecting portion that connects the stator blades and the inner rim of the stator formed in the metal plate by the cutting process in the radial direction of the stator is smaller than the length of the inner rim in the radial direction. A first casing having an intake port;
a second casing having an exhaust port;
a rotor having a shaft and disposed in a space sealed by at least the first casing and the second casing;
A plurality of rotor blades fixed to or integrally formed on an outer peripheral surface of the rotor;
a stator arranged alternately with the rotor blades in the axial direction of the shaft;
A drive unit that rotates the shaft;
a bearing that rotatably supports the shaft,
the stator has an outer circumferential rim located at an outer circumferential end of the stator, an inner circumferential rim located at an inner circumferential end of the stator, and a plurality of stator blades located between the outer circumferential rim and the inner circumferential rim,
the outer rim, the inner rim and the stator blades are integrally formed from metal plates,
an inclination angle of the stator blade with respect to the outer circumferential rim changes in a curved manner from an inner circumferential end to an outer circumferential end of the stator blade;
an upstream edge of a stator blade end portion located on the upstream side of the stator blade is curved from an inner peripheral end to an outer peripheral end of the stator blade, and a gap in the axial direction is constant with respect to a surface on which the downstream end portion of the rotor blade is disposed, the surface facing the upstream edge,
A vacuum pump characterized in that a width of a slit hole between the stator blades formed by cutting the metal plate in a direction perpendicular to an extension direction of the slit hole is 0.2 times or more the thickness of the metal plate. A first casing having an intake port;
a second casing having an exhaust port;
a rotor having a shaft and disposed in a space sealed by at least the first casing and the second casing;
A plurality of rotor blades fixed to or integrally formed on an outer peripheral surface of the rotor;
a stator arranged alternately with the rotor blades in the axial direction of the shaft;
A drive unit that rotates the shaft;
a bearing that rotatably supports the shaft,
the stator has an outer circumferential rim located at an outer circumferential end of the stator, an inner circumferential rim located at an inner circumferential end of the stator, and a plurality of stator blades located between the outer circumferential rim and the inner circumferential rim,
the outer rim, the inner rim and the stator blades are integrally formed from metal plates,
an inclination angle of the stator blade with respect to the outer rim varies from an inner end to an outer end of the stator blade;
an upstream edge of a stator blade end portion located on the upstream side of the stator blade is curved from an inner peripheral end to an outer peripheral end of the stator blade, and a gap in the axial direction is constant with respect to a surface on which the downstream end portion of the rotor blade is disposed, the surface facing the upstream edge,
a width in a direction perpendicular to an extension direction of a slit hole between the stator blades formed by cutting the metal plate so that the stator blade side end is formed in a curved shape that is concave in a direction away from an inclined center line passing through a center of an inner connection part of the stator blade to the inner rim and a center of an outer connection part of the stator blade to the outer rim, the width being 0.2 times or more the thickness of the metal plate. A first casing having an intake port;
a second casing having an exhaust port;
a rotor having a shaft and disposed in a space sealed by at least the first casing and the second casing;
A plurality of rotor blades fixed to or integrally formed on an outer peripheral surface of the rotor;
a stator arranged alternately with the rotor blades in the axial direction of the shaft;
A drive unit that rotates the shaft;
a bearing for rotatably supporting the shaft,
the stator has an outer circumferential rim located at an outer circumferential end of the stator, an inner circumferential rim located at an inner circumferential end of the stator, and a plurality of stator blades located between the outer circumferential rim and the inner circumferential rim,
the outer rim, the inner rim and the stator blades are integrally formed from metal plates,
an inclination angle of the stator blade with respect to the outer circumferential rim changes in a curved manner from an inner circumferential end to an outer circumferential end of the stator blade;
an upstream edge of a stator blade end portion located on the upstream side of the stator blade is curved from an inner peripheral end to an outer peripheral end of the stator blade, and a gap in the axial direction is constant with respect to a surface on which the downstream end portion of the rotor blade is disposed, the surface facing the upstream edge,
A stator, characterized in that a width in a direction perpendicular to an extension direction of slit holes between the stator blades formed by cutting the metal plate is 0.2 times or more the thickness of the metal plate. A first casing having an intake port;
a second casing having an exhaust port;
a rotor having a shaft and disposed in a space sealed by at least the first casing and the second casing;
A plurality of rotor blades fixed to or integrally formed on an outer peripheral surface of the rotor;
a stator arranged alternately with the rotor blades in the axial direction of the shaft;
A drive unit that rotates the shaft;
a bearing for rotatably supporting the shaft,
the stator has an outer circumferential rim located at an outer circumferential end of the stator, an inner circumferential rim located at an inner circumferential end of the stator, and a plurality of stator blades located between the outer circumferential rim and the inner circumferential rim,
the outer rim, the inner rim and the stator blades are integrally formed from metal plates,
an inclination angle of the stator blade with respect to the outer rim varies from an inner end to an outer end of the stator blade;
an upstream edge of a stator blade end portion located on the upstream side of the stator blade is curved from an inner peripheral end to an outer peripheral end of the stator blade, and a gap in the axial direction is constant with respect to a surface on which the downstream end portion of the rotor blade is disposed, the surface facing the upstream edge,
a stator blade side end portion of the metal plate being formed by cutting into a curved shape that is concave in a direction away from an inclined center line passing through the center of the inner connection portion of the stator blade to the inner rim and the center of the outer connection portion of the stator blade to the outer rim, the width of the stator blade in a direction perpendicular to the extension direction of the slit holes between the stator blades being 0.2 times or more the thickness of the metal plate.

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