JP6735119B2 - Vacuum pump and stationary blade part used for it - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vacuum pump used as a gas exhaust means of a process chamber in a semiconductor manufacturing apparatus, a flat panel display manufacturing apparatus, a solar panel manufacturing apparatus, and other chambers, and a vane portion used therefor, in particular, As a fixed blade that constitutes the vacuum pump, a high-rigidity fixed blade that prevents cracks due to drawing processing is provided to improve the durability, reliability, and exhaust performance of the vacuum pump.

A conventional vacuum pump of this type is disclosed in Patent Document 1, for example. The vacuum pump of Document 1 includes a turbo molecule part that transfers gas between a rotating blade part (6) and a stationary vane part (70).

The stationary vane portion (70) of the vacuum pump of Patent Document 1 includes a fixed vane (71) inclined at a predetermined angle and the fixed vane as disclosed in FIGS. A rim portion (75, 76) for supporting (71). This fixed wing (71) is formed by drawing, and in order to increase the rigidity of the fixed wing (71), the side wall of the fixed wing (71) is drawn by supporting side wall parts (75S, 76S). ) Are provided (see paragraph 0031 of the same document 1 and FIG. 3 of the same document 1).

In Patent Document 1, as a technique for preventing cracks due to drawing processing in the support side wall portion (75S) at the fixed blade side end portion as described above, a fixed blade ( 71), a configuration is provided in which a notch (75K) that is cut from the inclined tip toward the inclined root is provided (see paragraph 0031 of Document 1 and FIG. 3 of Document 1).

However, Patent Document 1 does not disclose or suggest the conditions under which cracks as described above are not generated. With the configuration in which such a notch (75K) is simply provided, it is not possible to reliably and effectively prevent cracks that occur in the support side wall portion (75S) due to drawing work, and it is possible to continue operation of the vacuum pump. As a result, such cracks gradually expand, leading to problems of durability and reliability as a vacuum pump. Further, if such a crack occurs even a little, the original function of the support side wall portion (75S) to increase the rigidity of the fixed blade (71) is deteriorated, and the inclination angle of the fixed blade (71) is likely to change. Since the fixed blade (71) is set to incline at an optimum angle for exhausting gas molecules, even if the inclination angle changes even slightly, there arises a problem that exhaust performance is deteriorated.

The reference numerals in parentheses in the above description are the reference numerals used in Patent Document 1.

JP, 2014-159805, A

The present invention has been made to solve the above problems, and an object thereof is to provide a fixed vane that constitutes a vacuum pump with a highly rigid fixed vane that prevents cracks due to drawing work, thereby improving durability. A vacuum pump suitable for improving reliability and exhaust performance and a vane portion used for the vacuum pump are provided.

In order to achieve the above object, the present invention provides a vacuum pump including a turbo molecular pump unit that transfers gas between a moving blade portion provided on a rotating body and a stationary blade portion fixed to a stationary body, The stationary vane portion has a fixed blade that is inclined at a predetermined angle and a rim portion that supports the fixed blade, and a side end portion of the fixed blade extends from the inclined root of the fixed blade toward the inclined tip thereof. The drawing process includes a formed support side wall part and is supported by the rim part through the support side wall part, and the drawing process for forming the support side wall part does not cause a crack in the support side wall part Before the above, the portion of the stationary vane portion, which becomes the supporting side wall portion by the drawing process, is set so as to satisfy the following expression (A).

"formula"
S×L×t1 ≧V Equation (A)
S: Radial width of the rotating body in the portion which becomes the supporting side wall portion by the drawing processing L: Circumferential length of the rotating body in the portion which becomes the supporting side wall portion by the drawing processing t1: Support side wall portion by the drawing processing Thickness of the portion to be S×L×t1: Volume of the portion to be the supporting side wall portion by the drawing process V: Volume of the supporting side wall portion after the drawing process

In the present invention, the stationary vane portion is a notch portion formed between the side end portion of the fixed blade and the rim portion so as to be cut from the inclined tip end of the fixed blade toward the inclined root. It may be characterized by having.

In the present invention, before the drawing process, the width of the notch portion in the radial direction of the rotating body is set to a dimension equal to or larger than the plate thickness of the rim portion. It may be a feature.

In the present invention, the width of the rim portion may be set to a dimension equal to or larger than the plate thickness of the rim portion.

In the present invention, the corner portion of the cutout portion may have an arc shape.

In the present invention, an eaves portion may be provided as a gas molecule backflow prevention structure on the intake port side of the cutout portion.

In the present invention, the eaves may be provided on the vane portion.

In the present invention, before the drawing process, when a cut in the fixed blade length direction is formed between the rim portion and a portion of the stationary blade that is the inclined tip of the fixed blade, the cut The width may be set to a dimension equal to or larger than the plate thickness of the rim portion.

In the present invention, the inclination angle of the support side wall portion with respect to the rim portion may be set to less than 90 degrees.

In the present invention, the tilt angle may be determined by the following formula (D).

"formula"
c≦R×b Equation (B)
R=(b+Δr)/b Equation (C)
θ=cos ⁻¹ (b/c) Equation (D)
c: Length of supporting side wall after drawing R: Limit elongation of material b: Length of supporting side wall after drawing onto a surface including the surface of the rim Δr: Material constituting the supporting side wall Limit elongation amount θ: Inclination angle of supporting side wall with respect to rim after drawing

In the present invention, the portion of the rim portion that is connected to the inclined root of the fixed blade may be inclined similarly to the fixed blade.

In the present invention, as a specific configuration of the vacuum pump, as described above, as a condition that a crack does not occur in the supporting side wall part by the drawing process for forming the supporting side wall part, before the drawing process, the drawing process of the stationary blade part is performed. Since the part which becomes the supporting side wall part satisfies the above formula (A), a defect due to a crack in the supporting side wall part occurring in the supporting side wall part, for example, a problem of durability as a vacuum pump or rigidity of a fixed blade. It is possible to prevent deterioration of the rigidity of the fixed blade due to the deterioration of the original function of the supporting side wall portion, and deterioration of the exhaust performance as a vacuum pump due to the change of the inclination angle of the fixed blade. It is possible to provide a vacuum pump having excellent performance and a stationary blade portion used for the vacuum pump.

The whole sectional view of the vacuum pump to which the present invention is applied. 1A is a plan view of a stationary vane portion that constitutes the vacuum pump of FIG. 1, and FIG. 1B is a plan view of two divided stationary vane portions that constitute the stationary vane portion. FIG. 3 is a schematic perspective view of a vane portion near the portion A in FIG. FIG. 4 is a view on arrow B in FIG. 3. The top view of the stationary vane part (divided stationary vane part) before drawing processing. CC sectional drawing in FIG. Explanatory drawing of the gas molecule backflow prevention structure applied to the vacuum pump of FIG. EE sectional drawing in FIG. FIG. 4 is an explanatory view of a divided stationary vane portion viewed from a direction of an arrow D in FIG. 3. Explanatory drawing of other embodiment of a vane part (divided vane part).

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.

1 is an overall cross-sectional view of a vacuum pump to which the present invention is applied, FIG. 2(a) is a plan view of a vane portion which constitutes the vacuum pump of FIG. 1, and FIG. 2(b) is its vane portion. It is a top view of two division|segmentation stationary blade parts.

The vacuum pump P of FIG. 1 transfers gas by a moving blade portion A1 provided on a rotor 7 which is a rotating body and a stationary blade portion A2 which is fixed to an outer case 1 which is a stationary body via a spacer 17. It is configured as a composite pump including a turbo molecular pump unit Pt and a screw groove pump unit Ps that transfers gas using the screw groove B, and includes, for example, a semiconductor manufacturing apparatus, a flat panel display manufacturing apparatus, It is used as a gas exhaust means for process chambers and other chambers in solar panel manufacturing equipment.

Referring to FIG. 1, an outer case 1 of a vacuum pump P shown in FIG. 1 is a bottomed cylinder in which a tubular pump case 1A and a bottomed tubular pump base 1B are integrally connected to each other in the tubular axial direction by fastening bolts. The upper end side of the pump case 1A is opened as an intake port 2 for sucking gas, and the exhaust port 3 for discharging gas is formed on the side face of the lower end portion of the pump base 1B. It is provided.

The intake port 2 is connected to a high vacuum chamber Ch, such as a process chamber of a semiconductor manufacturing apparatus, by a fastening bolt provided on a flange on the upper edge of the pump case 1A. Further, the exhaust port 3 is connected to the auxiliary pump via a pipe or a valve (not shown).

A cylindrical stator column 4 is erected at the center of the pump case 1A, and a rotor shaft 5 is provided at the center of the inside of the stator column 4. A magnetic bearing 6 is installed inside the stator column 4, and the magnetic bearing 6 supports the rotor shaft 5 rotatably around its axis.

A rotor 7 is provided outside the stator column 4, and the rotor 7 includes a tubular member 7B having a shape that covers the outer peripheral surface of the stator column 4, and an end member 7A having a shape that closes one end of the tubular member 7B. It has a structure with.

The tip of the rotor shaft 5 projects from one end of the stator column 4, and the tip of the rotor shaft 5 thus projected and the end member 7A of the rotor 7 are connected to each other, so that the rotor 7 is It has a structure integrated with 5.

Further, a drive motor 8 is provided inside the stator column 4, and the rotor 7 is rotated integrally with the rotor shaft 5 by rotationally driving the rotor shaft 5 around the shaft center by the drive motor 8. You can

By the way, in the vacuum pump P of FIG. 1, substantially the upper half of the rotor 7 functions as the turbo molecular pump portion Pt, and the substantially lower half of the rotor 7 functions as the thread groove pump portion Ps. The turbo molecular pump part Pt and the thread groove pump part Ps are specifically configured as follows.

<<Structure Description of Turbo Molecular Pump Pt>>
Referring to FIG. 1, the turbo-molecular pump unit Pt includes a rotating moving blade portion A1 and a stationary stationary blade portion A2 as a means for transferring gas from the intake port 1 toward the exhaust port 3 and a pump shaft center ( Specifically, a plurality of rotors 7 or rotor shafts 5 are alternately arranged along the axial center of the rotor 7 or the rotor shaft 5.

The rotor blade portion A1 is composed of a plurality of rotary blades 9 integrally formed on the outer peripheral surface of the rotor 7, and the plurality of rotary blades 9 are radially provided around the pump shaft center in the pump radial direction. Further, all of the plurality of rotary blades 9 are inclined at an angle optimum for exhausting gas molecules.

The stator vane portion A2 is obtained by abutting the two divided stator vane portions 11 (11A, 11B) shown in FIG. 2(b) from the outer peripheral surface side of the rotor 7 during assembly of the vacuum pump P. It is set in a ring like.

Referring to FIGS. 2A and 2B, each of the divided stationary vane portions 11 (11A, 11B) is similar to the fixed blade 10 that is inclined at a predetermined angle and the inner rim portion 12 that supports the fixed blade 10. And an outer rim portion 13 that supports the fixed wing 10. In addition, these split stationary vane portions 11 (11A, 11B), by abutting the ends of the inner rim portion 12 or the outer rim portion 13 with each other as a butt end 12a or a butt end 13a, It is configured as an annular stationary vane portion A2 as shown in FIG. A plurality of fixed blades 10 supported by the inner and outer rim portions 12 and 13 are also radially arranged in the same manner as the rotary blade 9 described above.

As a method for positioning and fixing the stationary blades 10 in the pump axial direction and the pump radial direction (direction orthogonal to the pump axial center; the same applies hereinafter), in the vacuum pump P of FIG. 1, a plurality of pump blades are provided along the inner peripheral surface of the pump case 1A. The spacers 17 are stacked and stacked, and the outer rim portion 13 is interposed between the stacked spacers 17.

With the plurality of fixed blades 10 arranged and set in the vacuum pump P by the positioning and fixing method as described above, each of the plurality of fixed blades 10 is preset so as to be inclined at an optimum angle for exhausting gas molecules. Has been done.

FIG. 3 is a schematic perspective view of the stationary blade portion near the portion A in FIG. 2A, FIG. 4 is a view taken in the direction of arrow B in FIG. 3, and FIG. Part), and FIG. 6 is a sectional view taken along the line CC in FIG.

Referring to FIG. 3, a connecting portion 18 that connects the inner and outer rim portions 12 and 13 is provided near the inclined root 10E of the fixed blade 10. The fixed blade 10 is supported by the inner and outer rim portions 12 and 13 by connecting the inclined root 10E of the fixed blade 10 to the connecting portion 18.

Of the both side ends 10-S1, 10-S2 of the fixed blade 10, the side end 10-S1 closer to the outer rim portion 13 is cut from the inclined tip 10T of the fixed blade 10 toward the inclined root 10E thereof. And a supporting side wall portion 102 (see FIG. 4) formed from the inclined root 10E of the fixed blade 10 toward the inclined tip 10T thereof. It is supported by the outer rim portion 13 via the support side wall portion 102. That is, the stationary vane portion A2 has the notch portion 101 formed as described above between the side end portion 10-S1 of the fixed blade 10 and the rim portion 13.

The rigidity of the fixed blade 10 in the inclination direction is enhanced by the support side wall portion 102, and even if a situation occurs in which another member comes into contact with the fixed blade 10 during assembly of the vacuum pump, for example, the optimally fixed fixation is achieved. The inclination angle of the blade 10 does not change easily.

The divided stationary vane portion 11 (11A, 11B) including the fixed blade 10 and the supporting side wall portion 102 as described above uses a die corresponding to the shape of the fixed blade 10 and the supporting side wall portion 102, and presses the fixed blade 10. Although it can be formed by drawing the support side wall portion 102, the pressing and drawing itself are well known, and therefore detailed description thereof will be omitted.

Among the both side end portions 10-S1 and 10-S2 of the fixed blade 10, the side end portion 10-S2 closer to the inner rim portion 12 also has the structure having the support side wall portion 102 as described above. .. The side end 10-S2 may be provided with the cutout 101 as described above.

As described above, the fixed blade 10 is formed by press working, and the supporting side wall portion 102 is formed by drawing. As a condition that the supporting side wall portion 102 is not cracked by the drawing work for forming the supporting side wall portion 102, In the vacuum pump P of FIG. 1, before the drawing process, the portion that becomes the support side wall part 102 by the drawing process of the stationary blade portion A2 is set to satisfy the following expression (1).

S×L×t1≧V Equation (1)
S: Radial width of the rotor 7 (rotating body) in the portion that becomes the supporting side wall portion by drawing (see FIG. 5)
L: Radial length of the rotor 7 (rotating body) in the portion that becomes the supporting side wall portion by drawing (see FIG. 5)
t1: Plate thickness of a portion which becomes a supporting side wall portion by drawing (see FIG. 6)
S×L×t1: Volume of a portion that becomes a supporting side wall portion by drawing processing V: Volume of a supporting side wall portion after drawing processing

The value of V may be obtained from an experiment. In the experiment, for example, the value of S, L or t1 is appropriately changed several times to perform the press working of the fixed blade 10 and the drawing of the supporting side wall portion 102, and then the presence or absence of cracks in the supporting side wall portion 102. By observing, S, L, and t1 at which cracks due to drawing are not finally generated are calculated and V is calculated.

Here, when the volume “S×L×t1” of the supporting side wall portion 102 before the drawing processing is set to be equal to “V” like “S×L×t1=V” in the formula (1) ( Equivalent setting), as can be seen from the deformation of the formula, that is, "S×L×t1=V", the volume "S×L×t1" of the supporting side wall portion 102 after drawing prevents cracks due to drawing. Is equal to the volume “V” of the supporting side wall portion 102 required for the above, the volume (S×L×t1=V) of the supporting side wall portion 102 before drawing is satisfied so as to satisfy “S×L×t1=V” in the formula (1). When L×t1) is set, cracks due to the drawing process in the support side wall portion 102 are effectively prevented.

Further, when the volume “S×L×t1” of the supporting side wall portion 102 before the drawing processing is set to be larger than “V” like “S×L×t1>V” in the formula (1), the further drawing Since the volume “S×L×t1” of the portion to be processed (support side wall portion 102 before drawing) is increased as compared with the equivalent setting described above, there is more room for drawing the support side wall 102, and The cracks in the support side wall portion 102 described above are less likely to occur.

The width s1 of the cutout portion 101 (=the width S of the support side wall portion, see FIG. 5) can be appropriately changed as necessary. However, when the cutout portion 101 is formed by punching, it is generally made of a material to be punched out. Considering that punching with a width smaller than the plate thickness is difficult, and ease of press working of the fixed blade 10 and drawing of the support side wall portion 102 are taken into consideration, as shown by the following formula (2), Before processing, the radial width s1 of the rotor 7 (rotating body) of the notch 101 may be set to a dimension equal to or larger than the plate thickness t2 of the rim portions 12 and 13. preferable.

s1≧t2 Equation (2)
s1: Radial width of the rotor (rotating body) at the cutout portion (=width S of the supporting side wall portion)
t2: Thickness of the rim (see Fig. 6)

The corners 101A and 101B (see FIG. 5) of the cutout 101 are located at the boundary with the support side wall 102 and are stretched by the drawing process of the support side wall 102. In order to prevent the cracks, it is preferable that the corners 101A and 101B of the cutout 101 have an arc shape.

The width s2 (see FIG. 5) of the outer rim portion 13 can be changed as appropriate, but the width s2 is, as shown by the following formula (3), the plate thickness t2 of the outer rim portion 13 (see FIG. 6). It is preferable to set the size equal to or larger than the above.

s2≧t2 Equation (3)
s2: width of the outer rim portion t2: plate thickness of the rim portion

The reason why it is preferable to set the width s2 of the rim portion 13 as described above is that the outer rim portion 13 is fixed as the pressing portion in the pressing work of the fixed blade 10 and the drawing work of the support side wall part 102. This is because if the width s2 of the rim portion 13 on the outer side of the plate thickness t2 is smaller, there is a high possibility that a problem in the drawing process will occur, such as the outer rim part 13 coming off from the mold during the drawing process.

The same applies to the case where the fixed blade 10 is pressed and the supporting side wall 102 is drawn while the inner rim 12 is fixed as the pressing portion. Therefore, in that case, the width of the inner rim portion 12 is preferably set to a dimension equal to or larger than the plate thickness of the material forming the rim portion 12.

FIG. 7 is an explanatory diagram of a gas molecule backflow prevention structure applied to the vacuum pump of FIG. 1. The sectional view of the divided stationary vane portion 11 (11A) shown in FIG. 7 corresponds to the sectional view of the divided stationary vane portion 11 (11A) viewed in the direction of arrow D in FIG.

The notch 101 described above is important for preventing cracks due to drawing of the support side wall portion 102, but on the other hand, causes backflow of gas molecules to the intake port 2 side, thereby reducing the exhaust performance of the vacuum pump P. Bring about a decline.

Therefore, in the vacuum pump P of FIG. 1, as shown in FIG. 7, the eaves portion 19 is provided on the intake port side of the cutout portion 101 as a gas molecule backflow prevention member, and the cutout portion 101 is formed by the eaves portion 19. The backflow of gas molecules therethrough is prevented, and the exhaust performance of the vacuum pump P is improved.

In the example of FIG. 7, the eaves portion 19 is integrally formed on the inner surface of the spacer 17 (see FIG. 1), but the invention is not limited to this. Although illustration is omitted, the eaves portion 19 may be supported by some fixing member (stationary body or the like) present in the vacuum pump P, such as the eaves portion 19 being provided on the stationary blade portion A2.

When the fixed blade 10 is formed by press working, a notch 20 in the fixed blade length direction is formed between the rim portion 12 and the rim portion 12 and the portion of the fixed blade 10 that is an inclined tip before drawing. 8)). The cut 20 in the length direction of the fixed blade is also formed by punching similarly to the cutout portion 101 described above, but as described above, it is generally difficult to punch a width smaller than the plate thickness of the material to be punched. Is. Therefore, the width s3 (see FIGS. 5 and 8) of the notch 20 in the fixed blade length direction is set to a size equal to or larger than the plate thickness t2 of the rim portions 12 and 13. Is preferred.

The stationary vane portion 11 (11A, 11B) including the fixed blade 10, the supporting side wall portion 102, and the rim portions 12 and 13 is formed of an aluminum steel plate or a stainless steel plate. The inclination angle θ (see FIG. 9) of 102 with respect to the rim portions 12 and 13 needs to be set to less than 90 degrees. The inclination angle θ can be determined as an inclination angle of less than 90 degrees by the following formula (6).

c≦R×b Equation (4)
R=(b+Δr)/b Equation (5)
θ=cos ⁻¹ (b/c) Equation (6)
c: Length of supporting side wall after drawing (see FIG. 9)
R: Limit elongation of material b: Length of the supporting side wall after drawing, which is projected on the surface including the surface of the rim (see FIG. 9)
Δr: Limiting elongation of the material forming the supporting side wall θ: Inclination angle of the supporting side wall after drawing to the rim

When the c value exceeds the R×b value, cracks are generated in the supporting side wall portion 102 due to the drawing process. Therefore, in order to prevent such cracks, the c value needs to satisfy the equation (5). .. That is, if the value of c satisfies the expression (5), cracks due to the drawing process on the support side wall portion 102 are unlikely to occur. Since θ is determined by including the c value in the equation (6), if the supporting side wall portion 102 is formed by drawing at the inclination angle of θ determined in the equation (6), It is unlikely that a crack due to processing will occur in the supporting side wall portion 102.

The portion 18 of the rim portion 12, 13 which is connected to the inclined root of the fixed blade 10 may be formed into a flat flat plate without inclination as shown in FIG. As shown in FIG. 5, the fixed blade 10 may be inclined similarly to the fixed blade 10. In this case, the inclined connecting portion 18 also has a function of imparting a downward momentum (a direction from the intake port 2 to the exhaust port 3) to the gas molecules, like the fixed blade 10, and thus is further improved as a vacuum pump. It can be expected to improve the exhaust performance.

<<Explanation of operation of turbo molecular pump unit Pt>>
In the vacuum pump P of FIG. 1, when the drive motor 8 is started, the rotor shaft 5, the rotor 7, and the plurality of rotary blades 9 rotate integrally. At this time, in the turbo molecular pump unit Pt, the uppermost rotor blade 9 imparts a downward momentum (a direction from the intake port 2 to the exhaust port 3) to the gas molecules incident from the intake port 2. The gas molecules having the downward momentum are sent to the rotary blade 9 side of the next stage by the fixed blade 10. By giving the momentum to the gas molecules and feeding the gas molecules as described above repeatedly in multiple stages in each stage of the moving blade portion A1 and the stationary blade portion A2, the gas molecules on the intake port 2 side are provided downstream of the rotor 7 ( In FIG. 1, the exhaust gas is exhausted so as to sequentially move toward the bottom of the rotor 7).

<<Structure Description of Thread Groove Pump Ps>>
Referring to FIG. 1, in the thread groove pump portion Ps, the thread groove flow path 15 is formed by the substantially lower half of the rotor 7 and the thread groove stator 14 located on the outer peripheral surface side of the rotor 7, and the thread groove flow path 15 is formed. Exhaust gas through. Specifically, in the vacuum pump P of FIG. 1, the lower half of the rotor 7 is surrounded by the cylindrical thread groove stator 14, and the thread groove B formed on the inner peripheral surface of the thread groove stator 14. And the outer peripheral surface of the rotor 7, the thread groove flow path 15 is provided on the outer peripheral surface side of the rotor 7.

The inlet (upstream end side) of the thread groove flow path 15 communicates with the downstream side of the turbo molecular pump unit Pt, and the outlet (downstream end side) of the thread groove flow path 15 passes through the in-pump exhaust flow path 16 and an exhaust port. It communicates with 3.

As another embodiment of the thread groove flow path 15, for example, the thread groove B of the thread groove stator 14 is omitted, and such a thread groove B is formed on the outer peripheral surface of the rotor 7, or the thread groove B. Can be formed on both the outer peripheral surface of the rotor 7 and the inner peripheral surface of the thread groove stator 14, and the thread groove B can be formed on a part of the outer peripheral surface of the rotor 7 or the thread groove stator 14. A structure formed on a part of the inner peripheral surface can also be adopted.

In the thread groove pump portion Ps having the above-described structure, the gas is transferred while being compressed by the drag effect on the thread groove B and the outer peripheral surface of the rotor 7. Therefore, the depth of the thread groove B is It is set so that it is deepest on the inlet side of 15 (flow passage opening end closer to the intake port 2) and shallowest on its outlet side (flow passage opening end closer to the exhaust port 3).

<<Explanation of screw groove pump operation>>
In the vacuum pump P of FIG. 1, gas molecules reach the inlet side of the thread groove flow passage 15 by the exhaust operation of the turbo molecular pump unit Pt. The reached gas molecules flow into the thread groove flow path 15, and are compressed from the transition flow to the viscous flow by the effect of the rotation of the rotor 7, that is, the drag effect on the outer peripheral surface of the rotor 7 and the thread groove B, and the exhaust flow in the pump Head to road 16. Then, the viscous flow of gas molecules that has reached the in-pump exhaust flow path 16 is exhausted from the exhaust port 3 to the outside of the outer case 1 by an auxiliary pump (not shown).

The present invention is not limited to the embodiments described above, and many modifications can be made by a person having ordinary skill in the art within the technical idea of the present invention.

For example, in the above-described embodiment, the example in which the supporting side wall portion is provided at the side end portion closer to the outer rim portion 13 of the both end portions of the fixed blade has been described, but the present invention is not limited thereto. Alternatively, the invention can be applied to an example in which the supporting side wall portion is provided at the side end portion on the side closer to the inner rim portion 12 of the both end portions of the fixed blade.

Further, the respective embodiments described above may be used in combination.

In the above-described embodiment, the composite pump including the turbo molecular pump unit Pt and the thread groove pump unit Ps has been described, but it may be used in an all-blade pump including only the turbo molecular pump unit Pt.

1 Exterior Case 1A Pump Case 1B Pump Base 2 Intake Port 3 Exhaust Port 4 Stator Column 5 Rotor Shaft 6 Magnetic Bearing 7 Rotor 7A End Member 7B Cylindrical Member 8 Drive Motor 9 Rotor Blade 10 Fixed Blade 10E Fixed Blade Inclined Root 10T Fixed Blade Of the inclined tip 10-S1 side end 10-S2 of the fixed blade closer to the outer rim portion side end portion 11 of the fixed blade closer to the inner rim portion split vane portion 11A first split vane portion 11B 2nd division|segmentation stationary vane part 12 Inner rim part 12a End part 13 of inner rim part Outer rim part 14 Screw groove stator 15 Screw groove flow passage 16 Pump exhaust flow passage 17 Spacer 18 Fixed blade of rim portion Portion connected to the inclined root 19 Eaves portion A1 Moving blade portion A2 Stator blade portion B Thread groove Ch Chamber P Vacuum pump Pt Turbo molecular pump portion Ps Thread groove pump portion

Claims (12)

In a vacuum pump including a turbo molecular pump unit that transfers gas with a moving blade portion provided on a rotating body and a stationary blade portion fixed to a stationary body,
The stationary blade portion has a fixed blade inclined at a predetermined angle, and a rim portion supporting the fixed blade,
The side end portion of the fixed blade includes a supporting side wall portion formed from an inclined root of the fixed blade toward the inclined tip end thereof, and is supported by the rim portion via the supporting side wall portion,
As a condition that a crack does not occur in the supporting side wall part by the drawing process for forming the supporting side wall part, before the drawing process, a portion of the stationary vane part which becomes the supporting side wall part by the drawing process is represented by the following formula ( A vacuum pump characterized by being set to satisfy A).
"formula"
S×L×t1 ≧V Equation (A)
S: Radial width of the rotating body in the portion which becomes the supporting side wall portion by the drawing processing L: Circumferential length of the rotating body in the portion which becomes the supporting side wall portion by the drawing processing t1: Support side wall portion by the drawing processing Thickness of the portion to be S×L×t1: Volume of the portion to be the supporting side wall portion by the drawing process V: Volume of the supporting side wall portion after the drawing process The stationary vane portion has a cutout portion between the side end portion of the fixed blade and the rim portion, which is cut out from the inclined tip of the fixed blade toward the inclined root. The vacuum pump according to claim 1. Before the drawing process, the radial width of the rotary body of the cutout portion is set to a dimension equivalent to or larger than the plate thickness of the rim portion. The vacuum pump according to 2. The vacuum pump according to any one of claims 1 to 3, wherein the width of the rim portion is set to a dimension equal to or larger than the plate thickness of the rim portion. The vacuum pump according to any one of claims 2 to 4, wherein a corner portion of the cutout portion has an arc shape. 6. The vacuum pump according to claim 1, wherein an eaves portion is provided as a gas molecule backflow prevention structure on the intake port side of the cutout portion. In the vane part,
The said eaves part is provided, The vacuum pump of Claim 6 characterized by the above-mentioned. Before the drawing process, when a cut in the fixed blade length direction is formed between the rim portion and the portion of the stationary blade that is the inclined tip of the fixed blade, the width of the cut is The vacuum pump according to any one of claims 1 to 7, wherein the size is set to be equal to or larger than the plate thickness of the rim portion. The vacuum pump according to any one of claims 1 to 8, wherein an inclination angle of the support side wall portion with respect to the rim portion is set to less than 90 degrees. The vacuum pump according to claim 9, wherein the inclination angle is determined by the following formula (D).
"formula"
c≦R×b Equation (B)
R=(b+Δr)/b Equation (C)
θ=cos ⁻¹ (b/c) Equation (D)
c: Length of supporting side wall after drawing R: Limit elongation of material b: Length of supporting side wall after drawing onto a surface including the surface of the rim Δr: Material constituting the supporting side wall Limit elongation amount θ: Inclination angle of supporting side wall with respect to rim after drawing The vacuum pump according to any one of claims 1 to 10, wherein a portion of the rim portion connected to the inclined root of the fixed blade is inclined similarly to the fixed blade. A stationary vane portion that constitutes the vacuum pump according to any one of claims 1 to 11.

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