JP6834612B2 - How to make a vacuum pump - Google Patents

Description

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

There is a vacuum pump having an exhaust part composed of a moving blade part and a stationary blade part arranged in multiple stages in the axial direction. The stationary blade portion has a plurality of stator bodies arranged in the circumferential direction. The stator body protrudes axially between the inner peripheral ribs and the outer peripheral ribs in an inclined state with respect to the inner peripheral ribs and the outer peripheral ribs. In order to raise the stator body in an inclined manner with respect to the inner and outer ribs, for example, the rising portion is plastically deformed by drawing or the like. The stationary blade portion formed by this processing method has a limit in the blade angle of the stator body because cracks occur in the plastically deformed portion when the blade angle of the stator body is increased.

Therefore, a method of forming a stator body is known in which a clearance is provided between the stator bodies adjacent to each other in the circumferential direction and between the stator body and the inner / outer peripheral ribs except for a part, and the portion between the clearances is bent in an axial direction. Has been done. In this method, first, a clearance is provided by punching, and then bending is performed to raise the blade in an axial direction to form a stator body having a predetermined blade angle. (See, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-348935

In the stationary blade portion described in Patent Document 1, since slits are formed in the stator main body by punching, the gap formed between the stator main bodies becomes large. Since the gap between the stator bodies causes a backflow of gas, the exhaust performance deteriorates. Further, in the stationary blade portion described in Patent Document 1, in order to form the stator main body, it is necessary to separately perform the slit forming step and the bending processing step, which increases the processing step and increases the manufacturing cost.

A method for manufacturing a vacuum pump according to a preferred embodiment of the present invention includes an exhaust portion in which a moving blade portion and a stationary blade portion are arranged in multiple stages in the axial direction, and the stationary blade portion includes an inner peripheral rib and an outer peripheral rib. The stator body is arranged between the inner peripheral rib and the outer peripheral rib and is inclined with respect to the inner peripheral rib and the outer peripheral rib, and at least one of the stationary blade portions is the stator. The main body is connected to the inner peripheral rib, the outer peripheral rail connected to the outer peripheral rib, the inner peripheral side cutting surface, the outer peripheral side cutting surface, the inner peripheral side cutting surface and the outer peripheral side. In a method for manufacturing a vacuum pump having a radial cut surface that connects a cut surface, a first mold having a first bent portion and a first mold having an unprocessed stationary blade portion sandwiched between the first mold and the first mold are opposed to each other. A second bent portion facing the first bent portion and a tip provided separately from the second bent portion and having a tip of the first mold rather than the second bent portion. A second mold having a cut portion protruding to the side is pressed against the unprocessed stationary blade portion to form the stator body by cutting and bending, and the cut portion includes the raw stationary blade portion. By cutting, the stator main body is cut and separated from the inner peripheral rib, the outer peripheral rib, and other stator main bodies adjacent in the circumferential direction, and the inner peripheral side cut surface, the outer peripheral side cut surface, and the radial direction are cut and separated. The stator body, in which each of the cut surfaces is formed and cut and separated by the cut portion, is inclined with respect to the inner peripheral rib and the outer peripheral rib by bending by the first and second bent portions .
In a more preferred embodiment, the cutting portion cuts and separates the stator main body from the inner peripheral rib to form the inner peripheral side cutting surface, and cuts the stator main body from the outer peripheral rib. An outer peripheral side cutting portion that is separated to form the outer peripheral side cutting surface, and a radial cutting portion that cuts and separates the stator body from another stator body adjacent in the circumferential direction to form the radial cutting surface. Including .
In a more preferred embodiment, the stator body has the circumferential length of the outer peripheral cut surface equal to or smaller than the circumferential length of the inner peripheral cut surface, or the stator body has the outer circumference. The blade angle at which the side cut surface is inclined with respect to the outer peripheral rib is smaller than the blade angle at which the inner peripheral side cut surface is inclined with respect to the inner peripheral rib.
In a more preferred embodiment, in the stator body, the height of the inner peripheral side blade in the region closest to the inner peripheral rib is substantially the same as the height of the outer peripheral side blade in the region closest to the outer peripheral rib.
In a more preferred embodiment, in the plurality of stages of the stationary blades arranged in the axial direction of the exhaust portion, at least the stationary blades arranged on the downstream side in the axial direction are formed by the cutting and bending process.

According to the vacuum pump of the present invention, the exhaust performance can be improved. Further, according to the method for manufacturing a vacuum pump of the present invention, the processing process can be reduced and the manufacturing cost can be reduced.

FIG. 1 is a cross-sectional view of a turbo molecular pump as a first embodiment of the vacuum pump according to the present invention. FIG. 2 is a plan view of the stationary blade portion of the present invention as viewed from above in the axial direction. FIG. 3 is an enlarged perspective view of the stationary wing portion shown in FIG. 2 in the vicinity of the stator main body. 4 (A) is a radial side view of the stator body as seen from the IVA-IVA direction of FIG. 2, and FIG. 4 (B) is an inner peripheral side view of the stator body as seen from the IVB direction of FIG. 4 (C) is a side view of the outer peripheral side of the stator body as viewed from the IVC direction of FIG. 5A and 5B show an example of a stationary blade portion arranged on the upstream side of the turbine blade exhaust portion shown in FIG. 1, FIG. 5A is a perspective view, and FIG. 5B is an inner peripheral side surface. FIG. 5 (C) is a side view on the outer peripheral side. FIG. 6 is a plan view for explaining a method of processing the stationary blade portion shown in FIG. FIG. 7 is an enlarged view of a part of the stationary wing portion illustrated in FIG. FIG. 8 is a diagram for explaining the structure of the stator body of the comparative example. 9 is a view of the stator body shown in FIG. 8, FIG. 9A is a radial side view, FIG. 9B is an inner peripheral side view, and FIG. 9C is an inner peripheral side view. It is a side view of the outer peripheral side. FIG. 10 is a diagram for explaining the structure of one embodiment of the stator body of the present invention. 11A and 11B are views of the stator main body shown in FIG. 10, FIG. 11A is a radial side view, FIG. 11B is an inner peripheral side view, and FIG. 11C is an inner peripheral side view. It is a side view of the outer peripheral side. FIG. 12 is a diagram for explaining the structure of another embodiment of the stator body of the present invention. 13 is a view of the stator body shown in FIG. 12, FIG. 13 (A) is a radial side view, FIG. 13 (B) is an inner peripheral side view, and FIG. 13 (C) is a side view. It is a side view of the outer peripheral side. 14A and 14B are schematic views of a mold forming a stator body, FIG. 14A is a perspective view of a punch, and FIG. 14B is a perspective view of a die. 15 is a cross-sectional view for explaining a method of forming a stator body using the mold shown in FIG. 14, and FIG. 15 (A) is a cross-sectional view of the cut surface of XVA-XVA of FIG. Yes, FIG. 15B is a cross-sectional view of the XVB-XVB cut plane of FIG. FIG. 16 is a perspective view showing an external shape of the stationary blade portion of the second embodiment of the present invention in the vicinity of the stator body. 17 is a view of the stator body shown in FIG. 16, FIG. 17 (A) is a radial side view, FIG. 17 (B) is an inner peripheral side view, and FIG. 17 (C) is a side view. It is a side view of the outer peripheral side.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
− First Embodiment −
FIG. 1 is a cross-sectional view of a turbo molecular pump as a first embodiment of the vacuum pump 1 according to the present invention. Hereinafter, an embodiment of the vacuum pump 1 will be described by taking a turbo molecular pump as an example. A power supply unit for supplying electric power is connected to the turbo molecular pump, but the illustration is omitted in FIG.
The vacuum pump 1 shown in FIG. 1 includes a turbine blade exhaust unit P1 provided with turbine blades and a thread groove exhaust unit P2 as exhaust function units.

The turbine blade exhaust portion P1 has a plurality of stages (exemplified as 6 stages in FIG. 1) of moving blades 17 formed on the pump rotor 3 and a plurality of stages (exemplified as 6 stages in FIG. 1) arranged on the pump casing 12 side. ) Is composed of the stationary blade portion 50. The moving blade portions 17 and the stationary blade portions 50 are alternately arranged in the axial direction. Each of the stationary blade portions 50 is fixed by sandwiching the outer peripheral edge thereof with spacers 5 arranged between the stationary blade portions 50. The thread groove exhaust portion P2 is provided on the downstream side of the turbine blade exhaust portion P1. The thread groove exhaust portion P2 is composed of rotor cylindrical portions 18a and 18b and screw stators 16a and 16b. The screw stator 16a is arranged on the inner peripheral side of the pump casing 12. The rotor cylindrical portion 18a is arranged between the screw stators 16a and 16b, and the rotor cylindrical portion 18b is arranged on the inner surface side of the screw stator 16b. One of the inner peripheral surface of the screw stator 16a and the outer peripheral surface of the low cylindrical portion 18a, one of the outer peripheral surface of the screw stator 16b and the inner peripheral surface of the rotor cylindrical portion 18a, and the inner peripheral surface of the screw stator 16b and the rotor cylindrical portion 18b. A thread groove is formed on one of the outer peripheral surfaces.

The pump rotor 3 is fastened to a shaft 10 which is a rotating shaft, and the shaft 10 is rotationally driven by a motor 4. As the motor 4, for example, a DC brushless motor is used, a motor stator 4a is provided on the base 2, and a motor rotor 4b is provided on the shaft 10. The rotating body unit R including the shaft 10 and the pump rotor 3 is rotatably supported by a permanent magnet magnetic bearing 6 using permanent magnets 6a and 6b and a bearing 30 which is a rolling bearing.

The permanent magnets 6a and 6b are ring-shaped permanent magnets magnetized in the axial direction. A plurality of permanent magnets 6a provided on the pump rotor 3 are arranged in the axial direction so that the same poles face each other. On the other hand, the plurality of permanent magnets 6b on the fixed side are attached to the magnet holder 11 fixed to the pump casing 12. A plurality of these permanent magnets 6b are also arranged in the axial direction so that the same poles face each other. The axial position of the permanent magnet 6a provided on the shaft 10 is set to be slightly above the position of the permanent magnet 6b arranged on the inner peripheral side thereof. That is, the magnetic poles of the permanent magnets on the rotating side are displaced by a predetermined amount in the axial direction with respect to the magnetic poles of the permanent magnets on the fixed side. The bearing capacity of the permanent magnet magnetic bearing 6 differs depending on the size of the predetermined amount. In the example shown in FIG. 1, since the permanent magnet 6a is arranged on the upper side of the drawing, the repulsive force between the permanent magnet 6a and the permanent magnet 6b causes the support force in the radial direction and the upward direction in the axial direction (direction toward the pump exhaust port side). ) Is acting on the rotating body unit R.

A bearing 9 is provided in the center of the magnet holder 11. The bearing 9 functions as a touchdown bearing that limits the runout of the upper part of the shaft 10 in the radial direction. In the steady rotation state, the shaft 10 and the bearing 9 do not come into contact with each other, and the shaft 10 becomes the bearing 9 when a large disturbance is applied or when the rotation of the shaft 10 becomes large during acceleration or deceleration of rotation. Contact.

The bearing 30 is housed in a bearing housing 31 fixed to the base 2. The bearing 30 is an oil-lubricated or grease-lubricated rolling bearing. A lower cover 19 is fixed to the lower part of the bearing housing 31 by using a fastening member such as a bolt.

An intake port 21 is provided above the pump casing 12.
The base 2 is provided with an exhaust port 25, and the exhaust port 25 is provided with an exhaust port 25a. By driving the rotating body unit R to rotate at high speed by the motor 4, the process gas sucked from the intake port 21 passes through the turbine blade exhaust portion P1 and the thread groove exhaust portion P2 from the exhaust port 25a of the exhaust port 25. It is exhausted. In FIG. 1, the gas flow is indicated by an arrow.

The stationary blade portion 50 constituting the turbine blade exhaust portion P1 is the stationary blade portion 60 arranged on the intake side of the turbine blade exhaust portion P1, in other words, the upstream side, and the exhaust side of the turbine blade exhaust portion P1, in other words. For example, it is provided with a stationary blade portion 70 arranged on the downstream side. The upstream-side stationary blade portions 60 are arranged in a plurality of stages (exemplified as three stages in FIG. 1) on the upstream side of the gas flow path, and the downstream-side stationary blade portions 70 are arranged below the upstream-side stationary blade portion 60. It is arranged in stages (exemplified as 3 stages in FIG. 1).
On the downstream side, in order to increase the compression ratio, it is preferable to use a stationary blade portion having a stator body having a small blade angle. Hereinafter, the first embodiment of the stationary blade portion 70 arranged on the downstream side will be described.

FIG. 2 is a plan view of the stationary blade portion of the present invention as viewed from above in the axial direction.
The stationary blade portion 70 is composed of a pair of split stationary blade portions 70A and 70B having a semi-ring shape in which a circular ring is divided into two. The split stationary blade portions 70A and 70B are arranged in a circular ring shape so that both end faces in the circumferential direction face each other, and the outer peripheral ribs 72 of the split stationary blade portions 70A and 70B are sandwiched by the spacer 5. The split wing portions 70A and 70B are formed in a shape symmetrical with respect to a straight line passing through the center of the circle, or a straight line extending to the left and right in the figure. It will be described as 70.
The stationary blade portion 70 has an inner peripheral rib 71, an outer peripheral rib 72, and a plurality of stator main bodies 73 arranged along the circumferential direction between the inner peripheral rib 71 and the outer peripheral rib 72.

FIG. 3 is an enlarged perspective view of the stationary wing portion shown in FIG. 2 in the vicinity of the stator main body. 4 (A) is a radial side view of the stator body as seen from the IVA-IVA direction of FIG. 2, and FIG. 4 (B) is an inner peripheral side view of the stator body as seen from the IVB direction of FIG. 4 (C) is a side view of the outer peripheral side of the stator body as viewed from the IVC direction of FIG.
The stator main body 73 is provided so as to be inclined with respect to the inner / outer peripheral ribs 71 and 72, and protrudes upward / downward in the axial direction. As shown in FIG. 4, the blade height hi on the inner peripheral side of the stator body 73 and the blade height ho on the outer peripheral side are substantially the same. An inner peripheral rail 74 connected to the inner peripheral rib 71 is provided at substantially the center of the circumferential length of the stator main body 73 on the inner peripheral side. An outer peripheral rail 75 connected to the outer peripheral rib 72 is provided at substantially the center of the circumferential length of the stator main body 73 on the outer peripheral side. That is, the stator main body 73 is connected by the inner / outer peripheral bars 74 and 75 and is integrally formed with the inner / outer peripheral ribs 71 and 72. The thicknesses of the inner and outer peripheral bars 74 and 75 are the same as those of the inner and outer peripheral ribs 71 and 72, respectively.
The lengths of the inner and outer peripheral bars 74 and 75 in the circumferential direction, and the blade angle θi on the inner peripheral side of the stator body 73 and the blade angle θo on the outer peripheral side are the blade height hi on the inner peripheral side of the stator body 73. The wing height ho on the outer peripheral side is set to be substantially the same. This will be described later.

The stator body 73 has an inner peripheral side surface 73a, an outer peripheral side side surface 73b, and a radial side surface 73c. The inner peripheral side surface 73a, the outer peripheral side side surface 73b, and the radial side surface 73c are cut surfaces cut from the inner peripheral rib 71, the outer peripheral rib 72, and the stator body 73 adjacent in the circumferential direction, respectively. Each of these cut surfaces is formed by being cut by a sharp cutting blade. Further, a step of cutting the inner peripheral side side surface 73a, the outer peripheral side side surface 73b, and the radial side surface 73c and cutting from the inner peripheral rib 71, the outer peripheral rib 72, and the stator main body 73 adjacent in the circumferential direction, respectively, and the stator main body 73. The step of inclining the inner / outer peripheral ribs 71 and 72 is performed at the same time in one step as a cutting and bending step. Details about these will also be described later.

5A and 5B show an example of a stationary blade portion 60 arranged on the upstream side of the turbine blade exhaust portion P1 illustrated in FIG. 1, FIG. 5A is a perspective view, and FIG. 5B is an inner circumference. It is a side side view, and FIG. 5C is an outer peripheral side side view.
Although not shown, the stationary blade portion 60 is also composed of a pair of split stationary blade portions having a semi-ring shape in which a circular ring is divided into two, like the stationary blade portion 70. The stationary blade portion 60 has an inner peripheral rib 61, an outer peripheral rib 62, and a plurality of stator main bodies 63 arranged along the circumferential direction between the inner peripheral rib 61 and the outer peripheral rib 62. In the stationary blade portion 60 arranged on the upstream side, the inner / outer peripheral side portions 63a and 63b of the stator main body 63 are formed by being plastically deformed so as to rise in an inclined manner from the inner / outer peripheral ribs 61 and 62, respectively. ..

That is, the stator main body 63 is formed in an inclined shape with an upward slope from the inner / outer peripheral ribs 61 and 62 in the circumferential direction by drawing the plate-shaped member. The stator body 63 is formed so as to project above the inner / outer ribs 61 and 62, in other words, only toward the intake port 21 side of the vacuum pump 1, and protrudes below the inner / outer ribs 61 and 62. Absent. Between the stator main bodies 63 arranged in the circumferential direction, a connecting portion 66 for connecting the inner peripheral rib 61 and the outer peripheral rib 62 is provided. Therefore, the stator main body 63 has an inner peripheral side side portion 63a, an outer peripheral side side portion 63b, a radial side surface 63c, and a connecting portion 64 connected to the delivery portion 66. The inner peripheral side portion 63a of the stator main body 63 is a plastically deformed portion connected to the inner peripheral rib 61 over the entire length in the circumferential direction. Further, a notch 63k is formed on the outer peripheral side side portion 63b of the stator main body 63 on the tip side corresponding to the radial side surface 63c, and the portion other than the notch 63k is a plastic deformation portion connected to the outer peripheral rib 62. It has become. A slit 67 is provided between the connecting portion 66 and the radial side surface 63c of the stator body 63.

The following two steps are required to form the stator body 63.
First step: The slit 67 on the radial side surface 63c side of the stator body 63 and the notch 63k are formed by punching.
Second step: After the first step, the inner peripheral side portion 63a and the outer peripheral side portion 63b of the stator main body 63 are plastically deformed by drawing, and the radial side surface 63c side has an upward slope. Form.

Since the stationary blade portion 60 is formed by plastically deforming the inner and outer peripheral side portions 63a and 63b of the stator main body 63, cracks are likely to occur in the plastically deformed portion. Therefore, the blade angle of the stator body 63 cannot be made too large in order to suppress the occurrence of cracks in the plastically deformed portion. On the other hand, in the stator body 73 of the stationary blade portion 70, since the inner / outer peripheral side surfaces 73a and 73b are cut from the inner / outer peripheral ribs 71 and 72, the blade angle can be increased. Normally, the blade angle of the stator body 63 of the stationary blade portion 60 is limited to about 15 degrees, but the blade angle of the stator body 73 of the stationary blade portion 70 can be made larger than that.

FIG. 6 is a plan view for explaining the processing method of the stationary blade portion shown in FIG. 2, and FIG. 7 is an enlarged view of a part of the stationary blade portion shown in FIG.
As shown in FIGS. 6 and 7, the stator body 73 is cut to form an inner peripheral side surface 73a, an outer peripheral side side surface 73b, and a radial side surface 73c. The stator main body 73 is bent so as to be inclined upward in the circumferential direction with respect to the ribs 71 and 72. Here, the cutting and bending process refers to a processing method in which cutting and bending are performed simultaneously in one process.
The stator body 73 is cut and bent along the alternate long and short dash line shown in FIGS. 6 and 7. The radial side surface 73c of the stator body 73 extends along a straight line passing through the center O of the circle (see FIG. 10 and the like), and the stator body 73 is formed in a fan shape in a plan view. Circumferential lengths Wi and Wo of the inner and outer circumference bars 74 and 75 (see FIG. 7), and blade angles θi and θo on the inner and outer circumference sides of the stator body 73 (see FIGS. 4B and 4C). Is set so that the blade height hi on the inner peripheral side of the stator body 73 and the blade height ho on the outer peripheral side are substantially the same. By making the blade height hi on the inner peripheral side of the stator body 73 substantially the same as the blade height ho on the outer peripheral side, the gap between the rotor blade portion 17 and the rotor blade portion 17 on the inner peripheral side of the stator body 73 can be set to the outer circumference of the stator body 73. Similar to the gap with the moving blade portion 17 on the side, it can be made smaller. If the gap between the stator main body 73 and the rotor blade portion 17 is large, the backflow of gas increases. In this way, the gap on the inner and outer peripheral sides of the stator main body 73 can be reduced together, so that the exhaust performance can be improved. Can be planned.
Hereinafter, the lengths Wi and Wo in the circumferential direction of the inner and outer peripheral bars 74 and 75 for making the blade heights hi and ho on the inner and outer peripheral sides of the stator body 73 substantially the same, and the inner and outer peripheral sides of the stator body 73. The relationship between the blade angles θi and θo will be described in comparison with a comparative example.

FIG. 8 is a diagram for explaining the structure of the stator body of the comparative example. 9A and 9B are views of the stator main body shown in FIG. 8, FIG. 9A is a radial side view, FIG. 9B is an inner peripheral side view, and FIG. 9C. ) Is a side view on the outer peripheral side.
In the stator body 83 of the comparative example shown in FIG. 8, the radial side surface 83c is located on a straight line passing through the center O of the circle. Further, the ends 85a and 85b on both sides of the outer peripheral rail 85, which are the connecting portions of the stator body 83 with the outer peripheral rib 82, are the ends on both sides of the inner peripheral rail 84, which is the connecting portion with the inner peripheral rib 81, respectively. It is located on the extension of the straight line connecting the portions 84a and 84b and the center O of the circle.
Therefore, in this state,
Circumferential length Wo of outer peripheral rail 85> Circumferential length Wi of inner peripheral rail 84
And also
Circumferential length Lo of outer peripheral side surface 83b> Circumferential length Li of inner peripheral side surface 83a
Is.
Here, the stator body 83 is inclined by a straight line connecting the end portion 85a of the outer peripheral rail 85 and the end portion 84a of the inner peripheral rail 84 and a straight line connecting the end portion 85b of the outer peripheral rail 85 and the end portion 84b of the inner peripheral rail 84. The bent state is shown in FIGS. 9A to 9C. In this state, the blade angle θi on the inner peripheral side of the stator body 83 and the blade angle θo on the inner peripheral side are equal (θi = θo).
Therefore, as illustrated in FIG. 9 (A),
Wing height ho on the outer circumference side> Wing height hi on the inner circumference side
Will be.

10 is a diagram for explaining the structure of one embodiment of the stator main body of the present invention, FIG. 11 is a view of the stator main body shown in FIG. 10, and FIG. 11 (A) is a radial direction. It is a side view, FIG. 11B is an inner peripheral side side view, and FIG. 11C is an outer peripheral side side view.
In the stator body 73 shown in FIG. 10, the circumferential length Lo of the outer peripheral side surface 73b of the stator main body 73 is larger than the circumferential length Li of the inner peripheral side surface 73a (Lo> Li). The radial side surface 73c is located on a straight line passing through the center O of the circle. In this embodiment, the blade angle θo on the outer peripheral side and the blade angle θi on the inner peripheral side are set so that the blade height ho on the outer peripheral side side surface 73b and the blade height hi on the inner peripheral side side surface 73a are equal to each other. .. That is, as shown in FIG. 13, the blade angle θo on the outer peripheral side is smaller than the blade angle θi on the inner peripheral side (θo <θi).

FIG. 12 is a diagram for explaining the structure of another embodiment of the stator main body of the present invention, FIG. 13 is a view of the stator main body shown in FIG. 12, and FIG. 13 (A) is a diameter. It is a directional side view, FIG. 13B is an inner peripheral side side view, and FIG. 13C is an outer peripheral side side view.
In the stator body 73 shown in FIG. 12, the radial side surface 73c is located on a straight line passing through the center O of the circle. However, the circumferential length Lo of the outer peripheral side surface 73b of the stator main body 73 and the circumferential length Li of the inner peripheral side surface 73a are equal (Lo = Li). Further, the circumferential length Wo of the outer peripheral rail 75, which is the connecting portion between the stator main body 73 and the outer peripheral rib 72, and the circumferential length of the inner peripheral rail 74, which is the connecting portion between the stator main body 73 and the inner peripheral rib 71. Wi is set so as to satisfy Lo = Li.
Therefore, in FIG. 13, if the blade angle θo on the outer peripheral side and the blade angle θi on the inner peripheral side are equalized (θo = θi), the blade height ho on the outer peripheral side and the blade height on the inner peripheral side of the stator body 73 are equal. It is equal to hi (ho = hi).

In this embodiment, the circumferential length Lo of the outer peripheral side surface 73b of the stator main body 73 is slightly smaller than the circumferential length Li of the inner peripheral side surface 73a (Lo <Li), and the outer peripheral side side surface 73b is set on the outer peripheral side. The blade angle θo may be made slightly larger than the blade angle θi on the inner circumference side (θo> θi).

Next, a method for forming the stator body of the present invention will be described.
14A and 14B are schematic views of a mold forming a stator body, FIG. 14A is a perspective view of a punch, and FIG. 14B is a perspective view of a die. 15 is a cross-sectional view for explaining a method of forming a stator body using the mold shown in FIG. 14, and FIG. 15 (A) is a cross-sectional view of the cut surface of XVA-XVA of FIG. Yes, FIG. 15B is a cross-sectional view of the XVB-XVB cut plane of FIG.
As shown in FIGS. 14 (A), 15 (A), and 15 (B), the punch 110 has a cut portion 112 and a bent portion 113 formed on the pedestal 111. The cutting portion 112 has an inner peripheral side cutting portion 112a, an outer peripheral side cutting portion 112b, and a radial cutting portion 112c. The inner peripheral side cutting portion 112a cuts the inner peripheral rib 71 to form the inner peripheral side side surface 73a of the stator main body 73. The outer peripheral side cutting portion 112b cuts the outer peripheral rib 72 to form the outer peripheral side side surface 73b of the stator main body 73. The radial cutting portion 112c forms the radial side surface 73c of the stator body 73. The radial side surface 73c is a surface formed by cutting the circumferential boundary surface of the adjacent stator body 73.

The inner peripheral side cutting portion 112a, the outer peripheral side cutting portion 112b, and the radial cutting portion 112c each have a sharp cutting edge at the tip portion. In the embodiment, each of the cut portions 112a to 112c gradually increases in width (112a and 112b are radial lengths and 112c is circumferential length) from the tip side to the root side, for example, a triangular cross section. It is formed in a shape. In this case, the cross section may be triangular over the entire length from the tip to the root, or only the tip side may be triangular in cross section, and the root side may be a straight shape having a rectangular cross section.

The bent portion 113 has an inclined surface 113a that is inclined with respect to the upper surface 111a of the pedestal 111. The bent portion 113 bends a portion of the stator body 73 above the inner / outer peripheral ribs 71 and 72 and a portion of the stator body 73 below the inner / outer ribs 71 and 72 in an inclined manner.

As shown in FIGS. 14 (B), 15 (A), and 15 (B), the die 120 has a bent portion 123 formed on the support portion 121. The support portion 121 has an inner peripheral side support portion 121a and an outer peripheral side support portion 121b. The inner peripheral side support portion 121a supports the inner peripheral edge of the stationary blade portion 70 to form the inner peripheral rib 71. The outer peripheral side support portion 121b supports the outer periphery of the stationary blade portion 70 to form the outer peripheral rib 72.

The bent portion 123 of the die 120 bends the portion above the inner / outer peripheral ribs 71 and 72 and the portion below the inner / outer peripheral ribs 71 and 72 of the stator body 73 in an inclined manner together with the bent portion 113 of the punch 110.

As shown in FIGS. 15A and 15B, the inner peripheral side support portion 121a and the outer peripheral side support portion 121b extend in the circumferential direction along the inner peripheral side surface or the outer peripheral side surface of the bent portion 123, respectively. A groove 124 is formed. Further, as shown in FIG. 15B, a groove 124a is formed between the bent portions 123 adjacent to the supporting portion 121 in the circumferential direction. When the stator body 73 is formed, the inner and outer peripheral side cutting portions 112a and 112b and the radial cutting portion 112c of the punch 110 are inserted into the grooves 124 and 124a.
The cutting blades 112a to 112c of the punch 110 enter the grooves 124 and 124a, and the inner and outer peripheral side surfaces 73a and 73b and the radial side surface 73c are formed.

An unprocessed stationary blade portion before forming the stator body 73 is set on the die 120, and the punch 110 is pushed out to the die 120 side. The raw stationary blade portion is formed in advance in the shape of a semicircular ring shown in FIG. By pushing the punch 110 toward the die 120, the raw stationary blade portion is cut by the cutting portion 112 of the punch 110. That is, the unprocessed stationary blade portion is cut by the inner peripheral side cutting portion 112a, the outer peripheral side cutting portion 112b, and the radial cutting portion 112c, and the inner peripheral side side surface 73a, the outer peripheral side side surface 73b, and the radial side surface 73c of the stator main body 73 are formed. It is formed. By further pushing the punch 110 toward the die 120, the raw stationary blade portion is bent by the bent portion 113 of the punch 110 and the bent portion 123 of the die 120 so as to be inclined with respect to the inner and outer peripheral ribs 71 and 72. Be done.

That is, in the method for forming the stator main body 73 according to the embodiment of the present invention, the stator main body 73 is formed by cutting and bending in which cutting and bending are performed at the same time (same step).
Therefore, the processing step can be reduced and the manufacturing cost can be reduced as compared with the conventional method in which the cutting step and the bending step are performed separately.
Further, the inner / outer peripheral side surfaces 73a and 73b and the radial side surface 73c of the stator main body 73 are formed by cutting with a sharp cutting edge. On the other hand, for example, in the punching process described in Patent Document 1, a clearance is set between the die and the punch for punching. The punched part is
It falls off from the work piece (base material).
In punching, if the clearance between the punch and the die is too small, cracks are formed in the portions of the workpiece corresponding to the punch edge and the die edge, and tongues are formed between the cracks. Will be done. That is, in the punching process, if the clearance between the punch and the die is too small, an uneven shear surface is formed. To avoid this, a properly sized clearance is required.

On the other hand, in the method of cutting with a sharp cutting edge, unlike punching, the workpiece is directly cut, so that the clearance of the cut portion can be made smaller than the width of the clearance formed by punching. The size of the clearance is related to the blade height ho of the stator body 73, and the smaller the clearance, the larger the blade height ho can be. Therefore, in one embodiment of the present invention, the blade height ho of the stator body 73 can be made larger than that of the stationary blade manufactured by the method of Patent Document 1, and the exhaust performance of the vacuum pump can be improved. it can.

Further, in one embodiment of the present invention, the outer peripheral side blade height ho of the stator main body 73 is substantially the same as the inner peripheral side blade height hi. Therefore, the gap between the inner peripheral side of the stator body 73 and the moving blade portion 17 is reduced, and the backflow of the exhausted gas can be suppressed. This also makes it possible to improve the exhaust performance of the vacuum pump.

According to the first embodiment of the present invention, the following effects are obtained.
(1) The stator body 73 includes an inner peripheral rail 74 connected to the inner peripheral rib 71, an outer peripheral rail 75 connected to the outer peripheral rib 72, an inner peripheral side side surface 73a, an outer peripheral side side surface 73b, and an inner peripheral side. It has a radial side surface 73c provided between the side surface 73a and the outer peripheral side surface 73b, and the inner peripheral side side surface 73a, the outer peripheral side side surface 73b and the radial side surface 73c have an inner peripheral rib 71, an outer peripheral rib 72 and a circumference, respectively. A cut surface cut from another stator body adjacent in the direction. Since the inner / outer peripheral side surfaces 73a and 73b and the radial side surface 73c of the stator main body 73 are formed by cutting, the gap in each cut portion can be minimized. In other words, the blade height of the stator body 73 can be reduced to the utmost limit. Therefore, the exhaust performance of the vacuum pump can be improved.

(2) In the stator body 73, the circumferential length of the outer peripheral side surface 73b is the same as or smaller than the circumferential length of the inner peripheral side surface 73a, or the outer peripheral side surface 73b is relative to the outer peripheral rib 72. The angle of the blade that is tilted is smaller than the angle at which the inner peripheral side surface 73a is tilted with respect to the inner peripheral rib 71. Therefore, the outer peripheral side blade height ho of the stator main body 73 can be brought closer to the inner peripheral side blade height hi. As a result, the gap between the inner peripheral side of the stator body 73 and the moving blade portion 17 is reduced, and the backflow of gas can be suppressed, so that the exhaust performance can be improved.

(3) In the stator main body 73, the inner peripheral side wing height hi from which the inner peripheral side surface 73a protrudes from the inner peripheral rib 71 is substantially the same as the outer peripheral side wing height ho protruding from the outer peripheral rib 72 of the outer peripheral side side surface 73b. .. In this way, by setting the inner peripheral side blade height hi of the stator main body 73 to be substantially the same as the outer peripheral side blade height ho, the backflow of gas on the inner peripheral side of the stator main body 73 can be sufficiently suppressed, and the exhaust performance can be suppressed. Can be improved.

(4) The stator main body 73 of the stationary blade portion 70 has the inner peripheral side side surface 73a, the outer peripheral side side surface 73b, and the radial side surface 73c, respectively, the inner peripheral rib 71, the outer peripheral rib 72, and other stator main bodies adjacent to each other in the circumferential direction. It is formed by cutting from 73 and inclining it with respect to the inner peripheral rib 71 and the outer peripheral rib 72. Therefore, the processing step when forming the stator main body 73 on the stationary blade portion 70 can be reduced, and the manufacturing cost can be reduced.

-Second embodiment-
A second embodiment of the present invention will be described with reference to FIGS. 16 and 17.
FIG. 16 is a perspective view showing an external shape of the stationary blade portion of the second embodiment of the present invention in the vicinity of the stator body. 17 is a view of the stator body shown in FIG. 16, FIG. 17 (A) is a radial side view, FIG. 17 (B) is an inner peripheral side view, and FIG. 17 (C) is a side view. It is a side view of the outer peripheral side.
In the first embodiment, the stator body 73 is formed so as to project in both the upper and lower directions of the inner and outer peripheral ribs 71 and 72. In the second embodiment, the stator body 73 is formed so as to project in only one of the inner / outer peripheral ribs 71 and 72 in the vertical direction.
As shown in FIGS. 16 and 17, the stator body 73 projects inclined in the axial direction only toward the upper side of the inner / outer peripheral ribs 71 and 72 (the intake port 21 side of the vacuum pump 1). ing. That is, one end side of the stator body 73 in the circumferential direction is connected to the inner / outer peripheral ribs 71 and 72, and the stator body 73 is formed in an upward slope from one end side to the other end side.

Also in the second embodiment, the inner peripheral side blade height hi of the stator main body 73 is substantially the same as the outer peripheral side blade height ho. In order to make the inner peripheral side blade height hi and the outer peripheral side blade height ho of the stator main body 73 substantially the same, the same structure as in the first embodiment may be adopted.
The other structures in the second embodiment are the same as those in the first embodiment, and the corresponding members are designated by the same reference numerals and the description thereof will be omitted.
The second embodiment also has the same effect as that of the first embodiment.

In the above embodiment, the vacuum pump 1 is exemplified as a ball bearing type turbo molecular pump. However, the present invention can be applied to a magnetic bearing type turbo molecular pump. Further, in the above embodiment, the vacuum pump 1 having the turbine blade exhaust portion P1 and the thread groove exhaust portion P2 is exemplified, but the present invention can be applied to a vacuum pump having only the turbine blade exhaust portion P1.

In the above embodiment, the structure is exemplified in which the stationary blade portions 60 are arranged on the upstream side of the turbine blade exhaust portion P1. However, the turbine blade exhaust portion P1 may be composed entirely of the stationary blade portion 70. In that case, the blade angle or blade height of the stationary blade portion 70 on the upstream side and the downstream side may be different.

Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included within the scope of the present invention.

1 Vacuum pump 3 Pump rotor 10 Shaft 17 Moving wing part 50 Static wing part 70 Static wing part 71 Inner peripheral rib 72 Outer rib 73 Stator body 73a Inner peripheral side side 73b Outer peripheral side side 73c Radial side side 74 Inner circumference rail 75 Outer rail hi Inner circumference side blade height ho Outer circumference side blade height P1 Turbine blade exhaust part Wi Inner circumference rail length in the circumferential direction Wo Outer circumference rail circumference length θi Inner circumference side blade angle θo Outer circumference side blade angle

Claims (5)

It has an exhaust section in which the moving blade section and the stationary blade section are arranged in multiple stages in the axial direction.
The stationary blade portion has an inner peripheral rib, an outer peripheral rib, and a stator body which is arranged between the inner peripheral rib and the outer peripheral rib and is inclined with respect to the inner peripheral rib and the outer peripheral rib. And
At least one of the stationary blade portions includes an inner peripheral rail in which the stator body is connected to the inner peripheral rib, an outer peripheral rail connected to the outer peripheral rib, an inner peripheral side cutting surface, and an outer peripheral side cutting surface. In a method for manufacturing a vacuum pump having a radial cut surface connecting the inner peripheral side cut surface and the outer peripheral side cut surface.
A first mold provided with a first bent portion and a second bent portion facing the first bent portion and facing the first bent portion with an unprocessed stationary blade portion interposed therebetween. A second mold provided separately from the second bent portion and having a cutting portion whose tip projects toward the side of the first mold with respect to the second bent portion is provided with the unprocessed static. Including the step of pressing the wing portion to form the stator body by cutting and bending.
By cutting the raw stationary blade portion at the cut portion, the stator main body is cut and separated from the inner peripheral rib, the outer peripheral rib, and other stator main bodies adjacent in the circumferential direction, and the inner peripheral side cut surface is cut. , Each of the outer peripheral side cut surface and the radial cut surface is formed.
A method for manufacturing a vacuum pump, wherein the stator body cut and separated by the cutting portion is inclined with respect to the inner peripheral rib and the outer peripheral rib by bending by the first and second bending portions. In the method for manufacturing a vacuum pump according to claim 1,
The cut portion is
An inner peripheral side cutting portion for forming the inner peripheral side cutting surface by cutting and separating the stator main body from the inner peripheral rib,
An outer peripheral side cut portion that cuts and separates the stator body from the outer peripheral rib to form the outer peripheral side cut surface, and
A method for manufacturing a vacuum pump, comprising a radial cutting portion that cuts and separates the stator main body from another stator main body adjacent in the circumferential direction to form the radial cut surface. In the method for manufacturing a vacuum pump according to claim 1 ,
In the stator body, the length of the outer peripheral side cut surface in the circumferential direction is the same as or smaller than the length in the circumferential direction of the inner peripheral side cut surface, or in the stator body, the outer peripheral side cut surface is the outer circumference. A method for manufacturing a vacuum pump, wherein the blade angle inclined with respect to the rib is smaller than the blade angle at which the inner peripheral side cutting surface is inclined with respect to the inner peripheral rib. In the method for manufacturing a vacuum pump according to claim 3 ,
A method for manufacturing a vacuum pump, wherein the height of the inner peripheral side blade of the region closest to the inner peripheral rib of the stator main body is substantially the same as the height of the outer peripheral side blade of the region closest to the outer peripheral rib. The method of manufacturing a pump according to any one of claims 1 to 4,
A method for manufacturing a vacuum pump, wherein in the plurality of stages of the stationary blades arranged in the axial direction of the exhaust portion, at least the stationary blades arranged on the downstream side in the axial direction are formed by the cutting and bending process.

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