Vacuum pump

Abstract

To restrain deformation of stators in a vertical direction.SOLUTION: A vacuum pump 1 comprises: a rotor 4 housed in a housing 2, and to be rotated and driven; a plurality of stages of rotor blades 22 provided in the rotor 4; and a plurality of stages of stators 5 arranged between the plurality of stages of rotor blades 22. The stators 5 comprise inner peripheral ribs 51, outer peripheral ribs 53, and stator blades 55 connecting the inner peripheral ribs 51 and the outer peripheral ribs 53, and are housed in the housing 2 while the outer peripheral ribs 53 are sandwiched between spacers 31. At least a portion of the outer peripheral ribs 53 of the stators 5 is provided with deformation allowance parts 57 for allowing deformation of the inner peripheral ribs 51 and / or the stator blades 55 in a radial direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vacuum pump. [Background technology]

[0002] Some vacuum pumps have a rotor with rotor blades and a stator arranged between the rotor blades (see, for example, Patent Document 1). In this vacuum pump, by rotating the rotor, the rotor blades move relative to the stator blades provided on the stator, sucking the inside of the device to be evacuated by the vacuum pump and discharging the sucked gas to the outside. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-139361 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described vacuum pump, the temperature of the stator may be adjusted to a high temperature, for example, to prevent the accumulation of by-products inside the vacuum pump. Even without temperature adjustment, the stator may become hot due to the high speed rotation of the rotor or the load of the gas being pumped. In conventional vacuum pumps, the temperature fluctuation of the stator due to temperature adjustment or the like can cause the stator to deform in the vertical direction (i.e., in the direction approaching the rotor blades), which can lead to the stator coming into contact with the rotor blades. Contact of the stator with the rotor blades can cause problems, such as improper operation of the vacuum pump or damage to the stator and / or rotor blades.

[0005] Therefore, an object of the present invention is to suppress deformation of the stator in the direction of the rotation axis, thereby operating the vacuum pump safely. [Means for solving the problem]

[0006] A vacuum pump according to one aspect of the present invention includes a rotor, multiple stages of rotor blades, and multiple stages of stators. The rotor is housed in a housing and driven to rotate. The multiple stages of rotor blades are provided on the rotor. The multiple stages of stators are arranged between the multiple stages of rotor blades. Each stator has an inner circumferential rib, an outer circumferential rib, and stator blades. The stator blades connect the inner circumferential rib and the outer circumferential rib. Each stator is housed in the housing with the outer circumferential rib sandwiched between spacers. At least a portion of the outer circumferential rib of the stator is provided with a deformation-permitting portion that permits radial deformation of the inner circumferential rib and / or the stator blades. [Effects of the Invention]

[0007] In a vacuum pump according to one aspect of the present invention, at least a portion of the outer circumferential rib of the stator is provided with a deformation-permitting portion that permits radial deformation of the inner circumferential rib and / or the stator blades. This allows the inner circumferential rib and / or the stator blades to deform radially even when the outer circumferential rib is sandwiched between spacers and thus is difficult to deform radially. As a result, for example, even when a temperature fluctuation occurs in the vacuum pump, the inner circumferential rib and / or the stator blades can deform radially, thereby preventing the inner circumferential rib and / or the stator blades from deforming in a direction toward the rotor blades. This prevents the stator from coming into contact with the rotor blades, allowing the vacuum pump to operate safely, even when a temperature fluctuation occurs in the vacuum pump. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of a vacuum pump. [Figure 2] FIG. 2 is an overall view of a stator element. [Figure 3] FIG. 10 is a cross-sectional view of a portion of the stator element where a deformation-permitting portion is provided. [Figure 4] FIG. 10 is a cross-sectional view of a deformation-permitting portion provided with a groove. [Figure 5] FIG. 10 is a cross-sectional view of a deformable portion having a hollow portion. [Figure 6] 10A and 10B are diagrams showing examples of non-circular through-holes, grooves, and hollows. DETAILED DESCRIPTION OF THE INVENTION

[0009] The vacuum pump will be described below with reference to Fig. 1. Fig. 1 is a cross-sectional view of a vacuum pump 1. The vacuum pump 1 includes a housing 2, a base 3, a rotor 4, and a stator 5 having multiple stages.

[0010] The housing 2 includes a first end 11, a second end 12, and a first internal space S1. An intake port 13 is provided in the first end 11. The intake port 13 is connected to the interior of the exhaust target device so that gas can flow therethrough. The first internal space S1 is in communication with the intake port 13. The second end 12 is located opposite the first end 11 in the axial direction of the rotor 4 (hereinafter simply referred to as the "axial direction A1"). The second end 12 is connected to the base 3. The base 3 includes a base end 14. The base end 14 is connected to the second end 12 of the housing 2. The base 3 is, for example, a member made of aluminum.

[0011] The rotor 4 is housed in the internal space of the housing 2. The rotor 4 includes a shaft 21. The shaft 21 extends in an axial direction A1. The shaft 21 is rotatably housed in the base 3. A thrust disk 21A is provided at the bottom of the shaft 21. Furthermore, a target 21B is screwed to the lower end of the shaft 21.

[0012] The rotor 4 includes multiple stages of rotor blades 22 and a rotor cylindrical portion 23. The multiple stages of rotor blades 22 are connected to the shaft 21 at an angle with respect to the axial direction A1. The multiple rotor blades 22 are arranged at intervals from one another in the axial direction A1. Although not shown, the multiple stages of rotor blades 22 each extend radially from the shaft 21 as a center. Note that in the drawings, only one of the multiple stages of rotor blades 22 is labeled with a reference numeral, and the reference numerals of the other rotor blades 22 are omitted. The rotor cylindrical portion 23 is arranged below the multiple stages of rotor blades 22. The rotor cylindrical portion 23 extends in the axial direction A1.

[0013] Each of the multiple stages of stators 5 is disposed on the base 3 via a spacer 31. When the housing 2 is fixed to the base 3, the stacked spacers 31 are sandwiched between the base 3 and the housing 2, and therefore, the outer circumferential ribs 53 ( FIG. 2 ) of the stators 5 are sandwiched between the spacers 31. As a result, the multiple stages of stators 5 are housed in the housing 2 while being spaced apart from one another in the axial direction A1. Specifically, each stator 5 is housed in the housing 2 with the outer circumferential rib of that stator 5 sandwiched between the two spacers 31. In other words, by sandwiching the outer circumferential rib of each stator 5 between the two spacers 31, two adjacent stators 5 are arranged at a predetermined interval within the housing 2.

[0014] The multiple stages of stators 5 are respectively arranged between the multiple stages of rotor blades 22. Specifically, the stator blades 55 (FIG. 2) of each stator 5 are arranged to face the adjacent rotor blades 22.

[0015] The stator 5 has a circular shape that fits the internal space of the housing 2. The stator 5 is composed of a plurality of stator elements 5a that are obtained by dividing the circular shape. In this embodiment, the stator 5 is composed of two stator elements 5a. That is, in this embodiment, the stator element 5a has a semicircular shape. Note that the stator 5 may be composed of two or more sector-shaped stator elements 5a, or may be composed of a single circular stator element 5a.

[0016] The vacuum pump 1 includes a screw stator 6. The screw stator 6 is fixed in contact with the base 3. The screw stator 6 is disposed facing the outer circumferential surface of the rotor cylindrical portion 23 with a small gap in the radial direction of the rotor cylindrical portion 23. A spiral groove is provided on the inner circumferential surface of the screw stator 6 facing the rotor cylindrical portion 23.

[0017] As shown in FIG. 1, an exhaust space S2 is formed downstream of the exhaust downstream end of the rotor cylindrical portion 23 and the screw stator 6. The exhaust target gas exhausted from the exhaust target device is guided into the exhaust space S2. The exhaust space S2 is in communication with an exhaust port 15. The exhaust port 15 is provided in the base 3. Another vacuum pump (not shown) is connected to the exhaust port 15. The exhaust downstream side refers to the side closer to the exhaust space S2 in the axial direction A1. The exhaust downstream direction refers to the direction toward the exhaust space S2.

[0018] The vacuum pump 1 includes bearings 44A and 44E, magnetic bearings 44B to 44D, and a motor 45. The bearings 44A and 44E are attached to the base 3 at positions where the shaft 21 is housed. The bearings 44A and 44E rotatably support the shaft 21. The bearings 44A and 44E are ball bearings. The magnetic bearings 44B to 44D are bearings that support the shaft 21 by magnetic force. Of these, the magnetic bearings 44B and 44C are radial magnetic bearings that support the shaft 21 in the radial direction. The magnetic bearing 44D is a thrust magnetic bearing that supports the shaft 21 in the axial direction.

[0019] The motor 45 drives the rotor 4 to rotate. The motor 45 includes a motor rotor 45A and a motor stator 45B. The motor rotor 45A is attached to the shaft 21. The motor stator 45B is attached to the base 3. The motor stator 45B is disposed opposite the motor rotor 45A.

[0020] In the vacuum pump 1, multiple stages of rotor blades 22 and multiple stages of stators 5 (stator blades) form a turbomolecular pump section. Furthermore, the rotor cylindrical section 23 and the screw stator 6 form a thread groove pump section. In the vacuum pump 1, when the rotor 4 is rotated by the motor 45, the gas to be pumped flows from the inside of the device to be pumped into the first internal space S1 via the intake port 13. The gas to be pumped in the first internal space S1 passes through the turbomolecular pump section and the thread groove pump section and is guided to the exhaust space S2. The gas to be pumped in the exhaust space S2 is exhausted from the exhaust port 15. As a result, the inside of the device to be pumped attached to the intake port 13 is brought into a high vacuum state.

[0021] A heater 71 and a cooling water pipe are provided on the outer wall of the base 3 to control the temperature of the base 3. The temperature of the base 3 is detected by a temperature sensor 72. Based on the temperature detected by the temperature sensor 72, the temperature of the base 3 is controlled by balancing the heating of the base 3 by the heater 71 and the cooling by the cooling water flowing through the cooling water pipe.

[0022] The specific configuration of the stator 5 (stator element 5a) will be described below with reference to FIG. 2. FIG. 2 is an overall view of the stator element 5a. The stator 5 of each stage is formed by combining multiple stator elements 5a. Generally, an annular stator 5 is formed by combining two stator elements 5a separated by 180 degrees as shown in FIG. 2 (only one of the two stator elements is shown in FIG. 2). The stator element 5a has an inner peripheral rib 51, an outer peripheral rib 53, and multiple stator blades 55.

[0023] The inner circumferential rib 51 forms the inner periphery of the stator 5. The rotor 4 is disposed in the space on the inner periphery side of the inner circumferential rib 51. That is, the inner diameter of the inner circumferential rib 51 is larger than the diameter of the rotor 4. The outer circumferential rib 53 is disposed a predetermined distance radially from the inner circumferential rib 51 and forms the outer periphery of the stator 5.

[0024] The stator blades 55 are provided to connect the inner peripheral ribs 51 and the outer peripheral ribs 53. The stator blades 55 extend radially from the shaft 21. The stator blades 55 are inclined in the opposite direction to the inclination of the rotor blades 22. For example, when the rotor blades 22 are inclined from the intake side to the exhaust side, the stator blades 55 are inclined from the exhaust side to the intake side. On the other hand, when the rotor blades 22 are inclined from the exhaust side to the intake side, the stator blades 55 are inclined from the intake side to the exhaust side. The inclination direction of the rotor blades 22 and the stator blades 55 can be determined appropriately depending on the rotation direction of the rotor 4, etc.

[0025] In the vacuum pump 1, certain products are generated from the raw materials flowing in from the equipment to be evacuated, and these products may accumulate inside the vacuum pump 1. To prevent this, the temperature of the vacuum pump 1 is adjusted using the heater 71 and / or cooling water piping of the vacuum pump 1. If the temperature of the vacuum pump 1 fluctuates due to this temperature adjustment, the inner peripheral rib 51 of the stator 5 and / or the stator blades 55 may deform in the vertical direction (toward the rotor blades 22). If this deformation becomes excessive, the stator blades 55 may come into contact with the rotor blades 22.

[0026] The present inventors have found that the reason why the inner circumferential rib 51 and / or the stator blades 55 deform significantly in the vertical direction when there is a temperature fluctuation in the vacuum pump 1 is that the outer circumferential rib 53 cannot deform within the plane of the stator 5 (i.e., in the radial direction of the stator 5) because the outer circumferential rib 53 is sandwiched between the spacers 31. Based on this finding, the present inventors have found that by providing the outer circumferential rib 53 with a deformation-permitting portion 57 (described below), the outer circumferential rib 53 is deformed in the radial direction of the stator 5, and the inner circumferential rib 51 and / or the stator blades 55 are deformed in the radial direction in response to this deformation, thereby suppressing the vertical deformation of the inner circumferential rib 51 and / or the stator blades 55.

[0027] As shown in FIG. 2, the deformable portions 57 are provided at the circumferential ends of the outer peripheral rib 53 of the stator element 5a. Preferably, the deformable portions 57 are provided at both circumferential ends of the outer peripheral rib 53 of the stator element 5a. That is, the deformable portions 57 are provided within a range of a predetermined length in the circumferential direction, starting from the circumferential end of the outer peripheral rib 53 of the stator element 5a. Although not particularly limited, the predetermined circumferential length generally corresponds to two to three stator blades 55. As shown in FIGS. 2 and 3, the deformable portions 57 are provided with a plurality of through-portions 571 that penetrate the outer peripheral rib 53 in the thickness direction. Specifically, the deformable portions 57 are provided with two large circular through-portions 571a, a small circular through-portion 571b disposed between the two large circular through-portions 571a, and one semicircular through-portion 571c provided at the end of the outer peripheral rib 53. FIG. 3 is a cross-sectional view of a portion of stator element 5a where deformation-permitting portion 57 is provided.

[0028] 2 and 3, the through-holes 571 form spaces within the plane of the outer peripheral rib 53 (i.e., within a plane including the radial direction of the stator 5). As a result, even if the outer peripheral rib 53 is sandwiched between the spacers 31, the through-holes 571 deform within the plane of the outer peripheral rib 53 due to temperature fluctuations, etc., and accordingly, the inner peripheral rib 51 and / or the stator blades 55 can deform in the radial direction of the stator 5. Because the inner peripheral rib 51 and / or the stator blades 55 can deform in the radial direction, deformation of the inner peripheral rib 51 and / or the stator blades 55 in the up-and-down direction (directions approaching the rotor blades 22) is suppressed.

[0029] Furthermore, by providing the semicircular through-holes 571c at both ends of the outer peripheral rib 53, the semicircular through-holes 571c can deform more greatly. This is because the ends of the outer peripheral rib 53 of the stator element 5a are connected to other stator elements 5a, and gaps exist in these connections. As a result, the inner peripheral rib 51 and / or the stator blades 55 can deform more greatly in the radial direction, which further suppresses deformation of the inner peripheral rib 51 and / or the stator blades 55 in the up-down direction.

[0030] 2 and 3, the deformable portion 57 has a thickness smaller than that of other portions of the outer peripheral rib 53. That is, as shown in FIG. 2, the deformable portion 57 is formed in a band-like shape with a small thickness in the circumferential direction starting from a circumferential end of the outer peripheral rib 53. A plurality of through-holes 571 are provided within this band-like area with a small thickness. As a result, when the outer peripheral rib 53 is sandwiched between two spacers 31, a gap is formed between the spacers 31 and the deformable portion 57. By forming a gap between the spacers 31 and the deformable portion 57, the deformable portion 57 becomes more easily deformable within the plane of the outer peripheral rib 53, and therefore the inner peripheral rib 51 and / or the stator blades 55 also become more easily deformed in the radial direction.

[0031] In the above-described vacuum pump 1, at least a portion of the outer peripheral rib 53 of the stator 5 is provided with a deformation-permitting portion 57 that permits radial deformation of the inner peripheral rib 51 and / or the stator blades 55. This allows the inner peripheral rib 51 and / or the stator blades 55 to deform radially even when the outer peripheral rib 53 is sandwiched between spacers and thus is difficult to deform radially. As a result, for example, even if a temperature fluctuation occurs in the vacuum pump 1, the inner peripheral rib 51 and / or the stator blades 55 can deform radially, thereby preventing the inner peripheral rib 51 and / or the stator blades 55 from deforming in a direction approaching the rotor blades 22. This prevents the stator 5 from coming into contact with the rotor blades 22, allowing the vacuum pump 1 to operate safely, for example, even if a temperature fluctuation occurs in the vacuum pump 1. In particular, by providing the deformation-permitting portions 57 at both circumferential ends of the outer peripheral rib 53 of the stator element 5a, the effect of suppressing deformation of the inner peripheral rib 51 and / or the stator blades 55 in a direction approaching the rotor blades 22 is more pronounced than when the deformation-permitting portions 57 are provided at the circumferential central portion of the outer peripheral rib 53 of the stator element 5a.

[0032] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[0033] In the vacuum pump 1 according to the above embodiment, the through-holes 571 are provided in the deformation-permitting portions 57 of the outer peripheral ribs 53, thereby facilitating deformation of the outer peripheral ribs 53 in the radial direction (within the plane of the stator 5). The through-holes 571 can be formed by a simple process of drilling holes in the outer peripheral ribs 53. However, the configuration for facilitating deformation of the outer peripheral ribs 53 is not limited to the through-holes 571. For example, as shown in FIG. 4, the outer peripheral ribs 53 can also be made to deform easily by providing grooves 573 in the deformation-permitting portions 57 that do not penetrate the outer peripheral ribs 53. The grooves 573 can be formed without penetrating the outer peripheral ribs 53, and therefore can be formed by a simple process. FIG. 4 is a cross-sectional view of the deformation-permitting portions 57 provided with the grooves 573.

[0034] Alternatively, for example, as shown in Fig. 5, the outer peripheral rib 53 can be made more easily deformable by providing a hollow portion 575, which is a space inside the outer peripheral rib 53, in the deformation-permitting portion 57. A stator 5 having the hollow portion 575 provided in the outer peripheral rib 53 can be formed using, for example, a 3D printer. The hollow portion 575 is not visible from the outside of the stator 5, and therefore the appearance of the stator 5 can be improved. Fig. 5 is a cross-sectional view of the deformation-permitting portion 57 having the hollow portion 575 provided therein.

[0035] The through portions 571, groove portions 573, and hollow portions 575 formed in the deformation-permitting portion 57 can have any shape other than a circle. For example, the through portions 571, groove portions 573, and hollow portions 575 can have V-shaped and triangular shapes alternately arranged as shown in Fig. 6. Fig. 6 is a diagram showing an example of the through portions 571, groove portions 573, and hollow portions 575 that are not circular.

[0036] The deformable portion 57 may be disposed at any position on the outer circumferential rib 53, as long as it is at least a part of the outer circumferential rib 53. For example, multiple deformable portions 57 may be disposed at equal intervals along the circumferential direction of the outer circumferential rib 53.

[0037] The through portions 571, groove portions 573, and hollow portions 575 formed in the deformation-permitting portion 57 can have any shape other than a circle. For example, the through portions 571, groove portions 573, and hollow portions 575 can have V-shaped and triangular shapes alternately arranged as shown in Fig. 6. Fig. 6 is a diagram showing an example of the through portions 571, groove portions 573, and hollow portions 575 that are not circular.

[0038] Deformable portion 57 may be formed by combining through portions 571, grooves 573, and / or hollow portions 575 of any shape.

[0039] The vacuum pump 1 according to the above embodiment is a pump that integrates a turbomolecular pump composed of multiple stages of rotor blades 22 and multiple stages of stators 5, and a thread groove pump composed of a rotor cylindrical portion 23 and a screw stator 6. However, the thread groove pump may be omitted. In other words, the stator 5 having the above-described deformable portion 57 can also be applied to a vacuum pump composed of only a turbomolecular pump.

[0040] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0041] (First Aspect) A vacuum pump (e.g., vacuum pump 1) according to the first aspect includes a rotor (e.g., rotor 4), multiple stages of rotor blades (e.g., rotor blades 22), and multiple stages of stators (e.g., stator 5). The rotor is housed in a housing (e.g., housing 2) and is driven to rotate. The multiple stages of rotor blades are provided on the rotor. The multiple stages of stators are disposed between the multiple stages of rotor blades. Each stator has an inner circumferential rib (e.g., inner circumferential rib 51), an outer circumferential rib (e.g., outer circumferential rib 53), and stator blades (e.g., stator blades 55). The stator blades connect the inner circumferential rib and the outer circumferential rib. Each stator is housed in the housing with the outer circumferential rib sandwiched between spacers (e.g., spacer 31). At least a portion of the outer circumferential rib of the stator is provided with a deformation-permitting portion (e.g., deformation-permitting portion 57) that permits radial deformation of the inner circumferential rib and / or the stator blades.

[0042] In the vacuum pump according to the first aspect, at least a portion of the outer peripheral rib of the stator is provided with a deformation-permitting portion that permits radial deformation of the inner peripheral rib and / or the stator blades. This allows the inner peripheral rib and / or the stator blades to deform radially even when the outer peripheral rib is sandwiched between spacers and thus is difficult to deform radially. As a result, for example, even if there is a temperature fluctuation in the vacuum pump, the inner peripheral rib and / or the stator blades can deform radially, thereby preventing the inner peripheral rib and / or the stator blades from deforming in a direction approaching the rotor blades. This prevents the stator from coming into contact with the rotor blades, allowing the vacuum pump to operate safely, even if there is a temperature fluctuation in the vacuum pump.

[0043] (Second Aspect) In the vacuum pump according to the first aspect, the stator of each stage may be composed of a plurality of stator elements (for example, stator element 5a). In this case, the deformation-permitting portion may be formed at the circumferential end of the outer peripheral rib of the stator element. The circumferential end of the outer peripheral rib of the stator element is a connecting portion with other stator elements, and a minute gap exists in this portion. As a result, the inner peripheral rib and / or the stator blades can deform more radially, so that deformation of the inner peripheral rib and / or the stator blades in the vertical direction is further suppressed.

[0044] (Third Aspect) In the vacuum pump according to the first or second aspect, the deformable portion may have a thickness smaller than that of the other portions of the outer peripheral rib. In the vacuum pump according to the third aspect, when the outer peripheral rib is sandwiched between the spacer, a gap is formed between the spacer and the deformable portion, making the deformable portion more likely to deform within the plane of the outer peripheral rib. As a result, the inner peripheral rib and / or the stator blades also more likely to deform radially.

[0045] (Fourth Aspect) In the vacuum pump according to any one of the first to third aspects, the deformable portion may have a through-hole (for example, through-hole 571) that passes through the outer peripheral rib. In the vacuum pump according to the fourth aspect, the through-hole can be formed by a simple process of drilling a hole in the outer peripheral rib, which makes it easy to process the stator 5.

[0046] (Fifth Aspect) In the vacuum pump according to any one of the first to fourth aspects, the deformable portion may have a hollow portion (for example, hollow portion 575) formed inside the outer peripheral rib. In the vacuum pump according to the fifth aspect, the groove portion can be formed by simple processing, which makes it easy to process the stator 5.

[0047] (Sixth Aspect) In the vacuum pump according to any one of the first to fifth aspects, the deformable portion may have a groove portion (for example, groove portion 573) formed in the outer peripheral rib. In the vacuum pump according to the sixth aspect, the hollow portion is not visible from the outside of the stator, which improves the appearance of the stator. [Explanation of symbols]

[0048] 1: Vacuum pump 2: Housing 3: Bass 4: Rotor 5: Stator 5a: Stator element 51: Inner rib 53: Peripheral rib 55: Stator blade 57: Deformation allowance section 571: Penetration 571a: Large circle penetration 571b: Small circular through hole 571c: Semicircular penetration 573: Groove 575: Hollow part 6: Screw stator 11: First end 12:Second end 13: Air intake 14: Base end 15: Exhaust port 21: Shaft 21A: Thrust disc 21B: Target 22: Rotor blade 23: Rotor cylindrical part 31: Spacer 44A, 44E: Bearings 44B~44D: Magnetic bearings 45: Motor 45A: Motor rotor 45B: Motor stator 71: Heater 72: Temperature sensor A1: Axial direction D1 :Direction S1: 1st internal space S2: Exhaust space

Claims

1. a rotor housed in a housing and driven to rotate; a plurality of stages of rotor blades provided on the rotor; a plurality of stages of stators disposed between the plurality of stages of rotor blades; Equipped with the stator has an inner peripheral rib, an outer peripheral rib, and a stator blade connecting the inner peripheral rib and the outer peripheral rib, and is housed in the housing with the outer peripheral rib sandwiched between spacers; At least a portion of the outer peripheral rib is provided with a deformation-permitting portion that permits radial deformation of the inner peripheral rib and / or the stator blade. Vacuum pump.

2. Each stage stator is composed of a plurality of stator elements, 2. The vacuum pump according to claim 1, wherein the deformation-permitting portion is formed at a circumferential end of an outer peripheral rib of the stator element.

3. 2. The vacuum pump according to claim 1, wherein the deformation-permitting portion has a thickness smaller than that of other portions of the outer peripheral rib.

4. The vacuum pump according to claim 1 , wherein the deformable portion has a through portion that passes through the outer peripheral rib.

5. The vacuum pump according to claim 1 , wherein the deformable portion has a hollow portion formed inside the outer peripheral rib.

6. The vacuum pump according to claim 1 , wherein the deformable portion has a groove formed in the outer peripheral rib.

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