Vacuum pump

Abstract

To provide a vacuum pump reduced in a size of a fixing structure in a bottom face side.SOLUTION: A vacuum pump 1 includes a vacuum pump body 100 and a bottom fixing plate 120. The vacuum pump body 100 has a bottom face 31 and a side face 32. The side face 32 includes a pump side flat surface 34 formed from the bottom face 31. The bottom fixing plate 120 is fastened to the bottom face 31 of the vacuum pump body 100. The bottom fixing plate 120 has a fixing side flat surface 56a facing to the pump side flat surface 34.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] In the field of semiconductor manufacturing equipment, etc., turbomolecular pumps, which are a type of vacuum pump, are used to create a high vacuum atmosphere. In turbomolecular pumps, a rotor rotates at high speed inside a casing, so a structure has been disclosed in which the energy generated when the rotor breaks is absorbed by deformation of a flange portion in order to prevent the energy from being transmitted to the device to which the turbomolecular pump is connected (for example, see Patent Document 1).

[0003] In order to ensure strength against impacts when the rotor of the vacuum pump breaks, the bottom side may also be fixed in addition to the top side where the flange is provided as in the above-mentioned Patent Document 1. As a fixing structure on the bottom side, for example, the vacuum pump body is fastened to a bottom fixing plate with a pump fixing bolt, and the bottom fixing plate is fastened to a fixing target with a bottom fixing bolt. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-003070 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the bottom fixing bolts need to be strong enough to withstand the impact of the destructive torque, so the number of bolts, the strength of the bolts, and the size of the bolt pitch circle diameter need to be ensured, which results in the large size of the fixing structure on the bottom side.

[0006] An object of the present invention is to provide a vacuum pump that allows the fixing structure on the bottom side to be made compact. [Means for solving the problem]

[0007] A vacuum pump according to a first aspect of the present invention includes a vacuum pump body and a bottom fixing member. The vacuum pump body has a bottom surface and a side surface. The side surface includes a first plane formed from the bottom surface. The bottom fixing member is fastened to the bottom surface of the vacuum pump body. The bottom fixing member has a second plane opposite to the first plane.

[0008] A vacuum pump according to a second aspect of the present invention includes a bottom surface and a side surface. The bottom surface is fastened to an object to be fixed. The side surface has a first plane formed from the bottom surface. When the bottom surface is fastened to the object to be fixed, the first plane faces a second plane formed on the object to be fixed. Effect of the Invention

[0009] According to the above-described aspects of the present invention, it is possible to provide a vacuum pump that allows the fixing structure on the bottom side of the vacuum pump to be made compact. [Brief description of the drawings]

[0010] [Figure 1] 1 is a front view of a vacuum pump according to an embodiment of the present invention. [Diagram 2] 1 is a diagram showing an internal configuration of a vacuum pump body according to an embodiment of the present invention; [Diagram 3] FIG. 2 is a perspective view showing the vicinity of the base and the bottom side fixing structure of the vacuum pump body of the embodiment according to the present invention. [Figure 4] 4(a) is a bottom view of the vacuum pump body according to the embodiment of the present invention, and (b) is an enlarged view of B in FIG. [Diagram 5] FIG. 2 is a perspective view of a bottom fixing plate according to an embodiment of the present invention. [Figure 6] 6(a) is a top view of a bottom fixing plate according to an embodiment of the present invention, and (b) is an enlarged view of part C in FIG. [Figure 7] 7(a) is a schematic plan view showing the positional relationship between a pump-side plane and a fixed-side plane of a vacuum pump according to an embodiment of the present invention, and (b) is a schematic view seen in the direction of arrow E in FIG. [Figure 8] FIG. 13 is a perspective view of a bottom plate according to a modified example of an embodiment of the present invention. [Figure 9] FIG. 11 is a front view of a vacuum pump according to a modified example of an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a vacuum pump system according to an embodiment of the present invention will be described with reference to the drawings.

[0012] <Configuration> (Vacuum Pump 1 Overview) FIG. 1 is a front view of a vacuum pump 1. The vacuum pump 1 includes a vacuum pump body 100 and a bottom fixing structure 110. The vacuum pump body 100 is connected to a chamber and exhausts gas in the chamber. The bottom fixing structure 110 fixes the bottom side of the vacuum pump body 100 to a fixing object 200. The fixing object 200 is, for example, a support frame that supports the chamber, but is not limited thereto. As will be described in detail later, the bottom fixing structure 110 has a bottom fixing plate 120. The vacuum pump body 100 is fastened to the bottom fixing plate 120, and the bottom fixing plate 120 is fastened to the fixing object 200, whereby the vacuum pump body 100 is fixed to the fixing object 200. In FIG. 1, a power supply unit 210 for driving the vacuum pump body 100 is disposed below the bottom fixing plate 120.

[0013] (Vacuum pump body 100) FIG. 2 is a cross-sectional view of the vacuum pump body 100 according to the embodiment.

[0014] The vacuum pump body 100 includes a turbine section P1 and a drag pump section P2. The turbine section P1 constitutes a turbo molecular pump. The drag pump section P2 constitutes a thread groove pump. The vacuum pump body 100 is connected to a chamber. Gas from the chamber is exhausted by the turbine section P1, then exhausted by the drag pump section P2, and exhausted to the outside of the vacuum pump body 100.

[0015] 2, the vacuum pump main body 100 has a housing 2, a rotor 3, a motor 4, a plurality of stator blade units 5, and a stator cylindrical portion 6. The housing 2 accommodates the rotor 3, the motor 4, the plurality of stator blade units 5, and the stator cylindrical portion 6.

[0016] The housing 2 has a casing 8, a base 9, and a fixing flange 10. The housing 2 is formed from a metal such as an aluminum alloy or iron. The casing 8 is a cylindrical member having the fixing flange 10 at one end.

[0017] The casing 8 houses a plurality of stator blade units 5 and a plurality of stages of rotor blade units 22 provided on the rotor 3. The casing 8 has a first end 11, a second end 12, and a side surface 13.

[0018] The first end 11 is attached to the exhaust target device. An intake port 14 is provided at the first end 11. The second end 12 is located on the opposite side of the fixed flange 10 on the central axis A of the rotor 3. The second end 12 is connected to the base 9. A side surface 13 is provided between the first end 11 and the second end 12. Inside the casing 8, a first internal space S1 is formed.

[0019] The base 9 is disposed so as to close the opening on the second end 12 side of the casing 8. The base 9 houses the stator cylindrical portion 6 and the rotor cylindrical portion 23 provided on the rotor 3. The base 9 is connected to the second end 12 of the casing 8 at the base end 33. A second internal space S2 is formed inside the base 9. The second internal space S2 communicates with the first internal space S1. An exhaust port 30 is formed on a side surface 32 of the base 9. A connector 16 that connects to an exhaust pipe is disposed in the exhaust port 30. The exhaust port 30 communicates with the second internal space S2. The configuration of the base 9 will be further described later.

[0020] The fixing flange 10 is connected to the casing 8. The fixing flange 10 protrudes from the casing 8. The fixing flange 10 is fixed to the exhaust target device by bolts. Note that "connection" includes the joining of separate members. Also, "connection" includes the joining of separate parts of an integrated member.

[0021] The rotor 3 has a shaft 21, multiple stages of rotor blade units 22, and a rotor cylindrical portion 23. The shaft 21 extends along the axis A of the rotor 3. In the following description, in the direction along the axis A, the direction from the casing 8 to the base 9 is defined as downward, and the opposite direction is defined as upward.

[0022] The vacuum pump main body 100 includes a protective bearing 29 and a plurality of bearings 24A-24C. The protective bearing 29 functions as a touch-down bearing that limits radial runout of the upper side of the shaft 21. The protective bearing 29 is attached to a base 9. When the shaft 21 is in a steady rotation state, the shaft 21 and the protective bearing 29 are not in contact with each other, but when a large disturbance is applied or when the whirling of the shaft 21 becomes large during acceleration or deceleration of the rotation, the shaft 21 comes into contact with the inner surface of the inner ring of the protective bearing 29. The protective bearing 29 can be, for example, a ball bearing.

[0023] The multiple bearings 24A-24C rotatably support the rotor 3. The multiple bearings 24A-24C are attached to a base 9. The multiple bearings 24A-24C include, for example, magnetic bearings. However, the multiple bearings 24A-24C may include other types of bearings, such as ball bearings.

[0024] The multiple stages of rotor blade units 22 are each connected to the shaft 21. The multiple stages of rotor blade units 22 are arranged at intervals from one another in a direction along the axis A. Each rotor blade unit 22 includes a plurality of rotor blades 25, and although not shown, each of the multiple rotor blades 25 extends radially from the shaft 21 as a center. Note that in the drawings, only one of the multiple stages of rotor blade units 22 and one of the multiple rotor blades 25 are labeled with a reference symbol, and the reference symbols of the other rotor blade units 22 and other rotor blades 25 are omitted.

[0025] The rotor cylindrical portion 23 is connected to the shaft 21. The rotor cylindrical portion 23 is disposed below the rotor blade unit 22. The rotor cylindrical portion 23 is cylindrical and extends in a direction along the axis A. The rotor cylindrical portion 23 is disposed so as to surround the shaft 21 on the outer circumferential side of the shaft 21.

[0026] The motor 4 rotates and drives the rotor 3. For example, a DC brushless motor is used as the motor 4. The motor 4 has a motor rotor and a motor stator. For example, the motor rotor is attached to a shaft 21. The motor stator is attached to a base 9. The motor stator is disposed to face the motor rotor.

[0027] The multiple stages of stator blade units 5 are connected to the inner surface of the casing 8. The multiple stages of stator blade units 5 are arranged at intervals from one another in the direction along the axis A. Each of the multiple stages of stator blade units 5 is arranged between the multiple stages of rotor blade units 22. Each of the stator blade units 5 includes a plurality of stator blades 28. Although not shown in the figure, the multiple stator blades 28 each extend radially from the shaft 21 as a center.

[0028] The multiple stages of rotor blade units 22 and the multiple stages of stator blade units 5 constitute a turbine section P1 (turbomolecular pump). In the drawings, only one of the multiple stator blade units 5 and one of the multiple stator blades 28 are labeled with a reference symbol, and the other stator blade units 5 and other stator blades 28 are omitted.

[0029] The stator cylindrical portion 6 is disposed radially outside the rotor cylindrical portion 23. The stator cylindrical portion 6 is connected to a base 9. The stator cylindrical portion 6 is disposed facing the rotor cylindrical portion 23 in the radial direction of the rotor cylindrical portion 23.

[0030] A helical thread is provided on the inner peripheral surface of the stator cylindrical portion 6. The rotor cylindrical portion 23 and the stator cylindrical portion 6 constitute a drag pump portion P2 (thread groove pump). Note that the helical thread may be provided on the outer peripheral surface of the rotor cylindrical portion 23 instead of the inner peripheral surface of the stator cylindrical portion 6.

[0031] (Base 9) Fig. 3 is a perspective view showing the vicinity of the base 9 and the bottom fixing plate 120. In Fig. 3, the bottom fixing plate 120 is indicated by a two-dot chain line. Fig. 4(a) is a bottom view of the vacuum pump main body 100. Fig. 4(b) is an enlarged view of part B in Fig. 4(a).

[0032] The base 9 is substantially cylindrical with a bottom. As shown in FIG. 2, the base 9 has a bottom surface 31, a side surface 32, and a base end portion 33. The bottom surface 31 is fixed to the bottom fixing plate 120. As shown in FIG. 4(a), the bottom surface 31 is formed with a plurality of bolt holes 31a into which pump fixing bolts 130 described later are inserted. The bolt holes 31a are arranged on a circumference centered on the axis A. The inner peripheral surface of the bolt holes 31a is formed with a female thread that screws into the male thread of the pump fixing bolt 130. In this embodiment, eight bolt holes 31a are formed, but only one is indicated by a reference number in FIG. 4(a).

[0033] The side surface 32 is disposed from the periphery of the bottom surface 31 toward the intake port 14. The base end portion 33 is disposed at the end of the side surface 32 on the intake port 14 side. The base end portion 33 protrudes outward (away from the axis A) from the side surface 32. As shown in Figs. 2 and 3, the base end portion 33 is connected to the second end portion 12 of the casing 8.

[0034] The outer shape of the side surface 32 is generally a shape of cylinders of different outer diameters lined up one above the other. The outer diameter of the side surface 32 is larger on the bottom surface 31 side than on the intake port 14 side. The side surface 32 has a pump-side flat surface 34 (first flat surface). The outer shape of the side surface 32 is not limited to this, and may be a cylinder of the same diameter.

[0035] The pump-side flat surface 34 is connected to the bottom surface 31, as shown in Figures 3, 4(a) and 4(b). The pump-side flat surface 34 is formed from an end of the bottom surface 31 toward the upward direction (toward the intake port 14). The pump-side flat surface 34 is disposed parallel to the axis A. When the vacuum pump body 100 is fixed to the bottom fixing plate 120, the pump-side flat surface 34 faces a fixing-side flat surface 56a (second flat surface) of the bottom fixing plate 120, which will be described later.

[0036] As shown in FIG. 3, the part of the side surface 32 near the bottom surface 31 that fits into the recess 54 of the bottom fixing plate 120 described later is defined as the side surface lower end portion 35. The side surface lower end portion 35 has a flat portion 35a and a curved portion 35b. The flat portion 35a is part of the pump side flat surface 34 (see FIG. 7(b) described later). The curved portion 35b is the part of the side surface lower end portion 35 other than the flat portion 35a. In a plan view, as shown in FIG. 4(a), the curved portion 35b is formed on the same circumference about the axis A. The flat portion 35a is on a straight line. The flat portion 35a overlaps with the pump side flat surface 34 in a plan view, so the reference number for the flat portion 35a is shown in parentheses in FIG. 4(a).

[0037] (Bottom side fixed structure 110) As shown in FIG. 1, the bottom side fixing structure 110 includes a bottom fixing plate 120 (bottom fixing member), a pump fixing bolt 130 (first fastening member) (see FIG. 3), a bottom fixing jig 140, and a bottom fixing bolt 150 (second fastening member). As shown in FIG. 3, the bottom fixing plate 120 is fastened to the vacuum pump body 100 by the pump fixing bolt 130. The bottom fixing jig 140 is disposed between the bottom fixing plate 120 and the fixing object 200. The bottom fixing bolt 150 is inserted from above through the bottom fixing plate 120 and the bottom fixing jig 140 to the fixing object 200. The bottom fixing bolt 150 is disposed parallel to the axis A. This allows the vacuum pump body 100 to be fixed to the fixing object 200.

[0038] Fig. 5 is a perspective view of the bottom fixing plate 120. Fig. 6(a) is a top view of the bottom fixing plate 120. Fig. 6(b) is an enlarged view of part C in Fig. 6(a).

[0039] The bottom fixing plate 120 has a main body 40 and a plurality of protrusions 41. The main body 40 is plate-shaped. The main body 40 has a first surface 51, a second surface 52, an opening 53, and a recess 54. The first surface 51 is the surface on which the vacuum pump main body 100 is placed. The second surface 52 is the surface on which the fixing target 200 is disposed.

[0040] The opening 53 penetrates the main body 40 from the first surface 51 to the second surface 52. The opening 53 is provided for passing cables and the like extending from the power supply unit 210 to the vacuum pump main body 100.

[0041] The recess 54 is formed in the first surface 51. The bottom surface 31 and the lower end portion 35 of the side surface of the vacuum pump body 100 fit into the recess 54. An opening 53 is formed in the recess 54. The recess 54 has a mounting surface 55 and an inner circumferential surface 56. The bottom surface 31 of the vacuum pump body 100 is placed on the mounting surface 55. The inner circumferential surface 56 is formed from the periphery of the mounting surface 55 toward the upper side. The inner circumferential surface 56 faces the lower end portion 35 of the side surface of the vacuum pump body 100.

[0042] The inner peripheral surface 56 includes a fixed side flat surface 56a and a curved surface 56b. When the vacuum pump body 100 is placed in the recess 54, the fixed side flat surface 56a faces the flat surface portion 35a. Since the flat surface portion 35a is included in the pump side flat surface 34, it can be said that the fixed side flat surface 56a faces the pump side flat surface 34. As shown in FIG. 5, the fixed side flat surface 56a is formed in a rectangular shape when viewed from a direction perpendicular to the axis A. The curved surface 56b is formed along the above-mentioned curved portion 35b of the vacuum pump body 100. As shown in FIG. 6(a), the curved surface 56b is formed on a circumference of the same radius centered on the axis A in a plan view. As shown in FIG. 6(b), the fixed side flat surface 56a is formed on a straight line in a plan view.

[0043] The main body 40 has a plurality of through holes 40a that penetrate from the second surface 52 to the mounting surface 55. The through holes 40a are arranged on a circumference centered on the axis A. In this embodiment, eight through holes 40a are formed, but only one is marked in the figure. For example, the inner peripheral surface of the through hole 40a is a smooth curved surface, and no female thread shape is formed. A pump fixing bolt 130 (see FIG. 3) is inserted from below through the through hole 40a of the bottom fixing plate 120 into the bolt hole 31a of the bottom surface 31 of the vacuum pump main body 100. The pump fixing bolt 130 is arranged parallel to the axis A. The male thread on the outer periphery of the pump fixing bolt 130 (an example of a fastening member) is screwed into the female thread on the inner periphery of the bolt hole 31a. This allows the vacuum pump main body 100 to be fixed to the bottom fixing plate 120.

[0044] The main body 40 is provided with a plurality of through holes 40b penetrating from the outer portion of the recess 54 of the first surface 51 to the second surface 52. The plurality of through holes 40b are arranged on a circumference centered on the axis A. In this embodiment, eight through holes 40b are formed, but only one is marked in the figure. For example, the inner peripheral surface of the through hole 40b is a smooth curved surface, and no female thread shape is formed. The through holes 40b are arranged along the periphery of the main body 40. The bolt 160 shown in FIG. 1 is inserted into a bolt hole formed on the upper surface of the power supply unit 210 through the through hole 40b. The male thread on the outer periphery of the bolt 160 is screwed into the female thread on the inner periphery of the bolt hole.

[0045] A plurality of protrusions 41 protrude outward from the outer periphery of the main body 40. In this embodiment, two protrusions 41 are provided. Each protrusion 41 is plate-shaped. A plurality of through holes 41a into which the bottom fixing bolt 150 is inserted are formed in each protrusion 41. In this embodiment, six through holes 41a are formed in one protrusion 41, but only one is marked in the figure. A bottom fixing jig 140 is disposed between the through holes 41a and the fixing object 200. The bottom fixing jig 140 is cylindrical. For example, the inner peripheral surface of the through hole 41a and the inner periphery of the bottom fixing jig 140 are smoothly curved surfaces, and no female thread shape is formed. The bottom fixing bolt 150 is inserted into the fixing object 200 from above through the through hole 41a of the protrusion 41 and the inside of the bottom fixing jig 140. The bottom fixing bolt 150 is disposed parallel to the axis A. The male thread on the outer periphery of the bottom fixing bolt 150 screws into the female thread on the inner periphery of the bolt hole of the fixing object 200. This allows the bottom fixing plate 120 to be fixed to the fixing object 200.

[0046] In the vacuum pump 1 of this embodiment, the pump side flat surface 34 of the vacuum pump body 100 and the fixed side flat surface 58 of the bottom fixing plate 120 are provided as flat surfaces facing each other. Therefore, when the rotor breaks, the pump side flat surface 34 abuts against the fixed side flat surface 56a, and the bottom fixing plate 120 can receive the breaking torque on its surface, thereby reducing the breaking torque applied to the bottom fixing bolt 150.

[0047] A gap is provided between the inner peripheral surface 56 of the bottom fixing plate 120 and the lower end portion 35 of the side surface. FIG. 7(a) is a schematic plan view showing the positional relationship between the pump side plane 34 and the fixed side plane 56a. FIG. 7(a) illustrates the lower end portion 35 of the side surface in FIG. 6(b). FIG. 7(b) is a schematic view of FIG. 7(a) viewed along the arrow E. The gap d between the pump side plane 34 and the fixed side plane 56a is formed smaller than the gap between the inner peripheral surface of the through hole 41a of the bottom fixing plate 120 and the bottom fixing bolt 150. In addition, it is preferable that the gap d is smaller than the smallest gap between the multiple bottom fixing bolts 150 and the inner peripheral surface of the through hole 41a. As a result, when the rotor 3 is broken, the pump side plane 34 comes into contact with the fixed side plane 56a before the bottom fixing bolt 150 comes into contact with the through hole 41a, so that the breaking torque applied to the bottom fixing bolt 150 can be reduced.

[0048] In addition, if the width of the pump-side flat surface 34 in a plan view is W1 and the width of the fixed-side flat surface 56a is W2, it is preferable that W2 is larger than W1. It is also preferable that the widths W1, W2 and the gap d are set so that the pump-side flat surface 34 comes into contact with the fixed-side flat surface 56a when the vacuum pump body 100 rotates about the axis A relative to the bottom fixed plate 120.

[0049] (Other embodiments) 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.

[0050] In the above embodiment, only one pair of the pump-side flat surface 34 and the fixed-side flat surface 56a is provided, but multiple pairs may be provided.

[0051] In the above embodiment, the pump-side flat surface 34 extends above the fixed-side flat surface 56a, but may be formed up to a portion (flat surface portion 35a) at the same height as the fixed-side flat surface 56a.

[0052] In the above embodiment, the recess 54 is formed in the bottom fixing plate 120, and the fixed side flat surface 56a facing the pump side flat surface 34 is provided on the inner peripheral surface 56 of the recess 54, but this configuration is not limited to this. FIG. 8 is a perspective view showing a modified bottom fixing plate 320. In the bottom fixing plate 320, the recess 54 is not formed on the first surface 351 of the main body portion 340, as compared with the bottom fixing plate 120. The bottom fixing plate 320 has a convex portion 354 on the first surface 351. The convex portion 354 has a fixed side flat surface 354a facing inward. The fixed side flat surface 354a faces the pump side flat surface 34 when the vacuum pump body 100 is fixed to the bottom fixing plate 320. In this way, the surface facing the pump side flat surface 34 may be provided on the convex portion 354, not on the inner peripheral surface 56 of the recess 54.

[0053] In the above embodiment, two protrusions 41 are provided, and six through holes 41a are formed in each of the protrusions 41, but the number is not limited to this. Similarly, the number of through holes 40a, 40b is not limited to eight.

[0054] In the above embodiment, the power supply unit 210 is arranged below the bottom fixing plate 120, and the bottom fixing plate 120 and the power supply unit 210 are fastened with bolts, but the power supply unit 210 does not have to be arranged below the bottom fixing plate 120.

[0055] In the above embodiment, the vacuum pump body 100 is fixed to the object 200 via the bottom fixing plate 120, but as shown in Fig. 9, the vacuum pump body 100 may be directly fixed to the object 200. In this case, the recess 54 in which the fixing side flat surface 56a is formed is formed on the front surface 200a of the object 200. The pump fixing bolt 130 is inserted from the back surface 200b side of the object 200. In this manner, the pump side flat surface 34 of the vacuum pump body 100 may face the fixing side flat surface 56a of the object 200.

[0056] In the above embodiment, it has been described that a gap is provided between the inner peripheral surface 56 of the bottom fixing plate 120 and the lower end portion 35 of the side surface, but there may be no gap provided between the lower end portion 35 of the side surface of the vacuum pump body 100 and the inner peripheral surface 56 of the bottom fixing plate 120 in whole or in part and they may be in contact with each other. Also, there may be no gap provided between the pump side flat surface 34 and the fixed side flat surface 56a and they may be in contact with each other.

[0057] (Aspect) It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0058] (Item 1) A vacuum pump according to a first aspect includes a vacuum pump body and a bottom fixing member. The vacuum pump body has a bottom surface and a side surface. The side surface includes a first plane formed from the bottom surface. The bottom fixing member is fastened to the bottom surface of the vacuum pump body. The bottom fixing member has a second plane opposite to the first plane.

[0059] According to the vacuum pump of the first aspect, if the rotor of the vacuum pump body breaks, the first flat surface of the vacuum pump body comes into contact with the second flat surface of the bottom fixing member. In this way, the bottom fixing member can receive the breaking torque generated in the vacuum pump body on its surface, and the breaking torque applied to the second fastening member used to fix the bottom fixing member to the object to be fixed can be reduced. Therefore, the number of second fastening members can be reduced, their strength can be lowered, and the bolt pitch circle diameter (the diameter of a circle whose radius is the length from the central axis of the rotor to the bolt) can be reduced. This allows the fixing structure on the bottom side of the vacuum pump to be made smaller.

[0060] (2) In the vacuum pump according to the 1st aspect, the bottom fixing member may have a recess into which the bottom surface of the vacuum pump body fits. The recess may have a mounting surface on which the bottom surface is mounted and an inner peripheral surface disposed around the upper surface. The second plane may be disposed on the inner peripheral surface.

[0061] According to the vacuum pump of the second aspect, if the rotor breaks, the first flat surface of the vacuum pump body comes into contact with the second flat surface formed on the inner circumferential surface of the recess, allowing the bottom fixing member to receive the breaking torque on its surface.

[0062] (Item 3) In the vacuum pump described in item 1, the bottom surface and the bottom fixing member may be fastened by a first fastening member. The first fastening member may be disposed parallel to the first plane.

[0063] According to the vacuum pump according to the third aspect, in the event of the rotor breaking, it is possible to reduce the breaking torque applied to the first fastening member which fastens the vacuum pump body and the bottom fixing member.

[0064] (Item 4) In the vacuum pump described in item 1, the bottom fixing member may be fastened to the fixing object by a second fastening member on an outer side of the bottom surface. The second fastening member may be disposed parallel to the first plane.

[0065] According to the vacuum pump of the fourth aspect, in the event of the rotor breaking, it is possible to reduce the breaking torque applied to the second fastening member which fastens the bottom fixing member and the fixed object.

[0066] (Item 5) In the vacuum pump described in item 3, the bottom fixing member may have a through hole through which the second fastening member passes, and the second fastening member may be inserted into the fixing object through the through hole. A gap between the first plane and the second plane may be smaller than a gap between an inner circumferential surface of the through hole and the second fastening member.

[0067] According to the vacuum pump of the fifth aspect, if the rotor breaks, the first plane contacts the second plane before the second fastening member contacts the inner circumferential surface of the through hole, thereby reducing the breaking torque applied to the fastening members.

[0068] (Item 6) A vacuum pump according to a second aspect includes a bottom surface and a side surface. The bottom surface is fastened to an object to be fixed. The side surface has a first plane formed from the bottom surface. When the bottom surface is fastened to the object to be fixed, the first plane faces a second plane formed on the object to be fixed.

[0069] According to the vacuum pump according to the sixth aspect, if the rotor of the vacuum pump body breaks, the first flat surface of the vacuum pump body comes into contact with the second flat surface of the bottom fixing member. In this way, the bottom fixing member can receive the breaking torque generated in the vacuum pump body on its surface, and the breaking torque applied to the fastening member that fastens the bottom fixing member to the vacuum pump body, or the fastening member used to fasten the bottom fixing member to the object to be fixed, can be reduced. Therefore, the number of the first fastening members and the second fastening members can be reduced, the strength can be lowered, and the bolt pitch circle diameter (the diameter of the circle whose radius is the length from the central axis of the rotor to the bolt) can be reduced. This allows the fixing structure on the bottom side of the vacuum pump to be made smaller. [Explanation of symbols]

[0070] 1: vacuum pump, 2: housing, 3: rotor, 4: motor, 5: stator blade unit, 6: stator cylindrical portion, 8: casing, 9: base, 10: fixing flange, 11: first end, 12: second end, 13: side, 14: intake port, 16: connector, 21: shaft, 22: rotor blade unit, 23: rotor cylindrical portion, 24A-24C: bearing, 25: rotor blade, 28: stator blade, 29: protective bearing, 30: exhaust port, 31: bottom surface, 31a: bolt hole, 32: side surface, 33: base portion, 34: pump side flat surface, 35: lower end of side surface, 35a: flat portion, 35b: curved portion, 40: main body portion, 40a: through hole, 40b: through Hole, 41: protrusion, 41a: through hole, 51: first surface, 52: second surface, 53: opening, 54: recess, 55: mounting surface, 56: inner peripheral surface, 56a: fixed side flat surface, 56b: curved surface, 100: vacuum pump body, 110: bottom side fixing structure, 120: bottom fixing plate, 130: pump fixing bolt, 140: bottom fixing jig, 150: bottom fixing bolt, 160: bolt, 200: fixing object, 200a: front surface, 200b: back surface, 210: power supply unit, 320: bottom fixing plate, 340: main body, 351: first surface, 354: convex portion, A: shaft, P1: turbine portion, P2: drag pump portion, S1: first internal space, S2: second internal space, d: gap

Claims

1. a vacuum pump body having a bottom surface and a side surface including a first plane formed from the bottom surface; a bottom fixing member fastened to the bottom surface of the vacuum pump body, The bottom fixing member has a second plane opposite to the first plane. Vacuum pump.

2. the bottom fixing member has a recess into which the bottom surface of the vacuum pump body fits, The recess has a mounting surface on which the bottom surface is placed and an inner circumferential surface disposed around the mounting surface, The second plane is disposed on the inner circumferential surface.

2. A vacuum pump as claimed in claim 1.

3. The bottom surface and the bottom fixing member are fastened by a first fastening member, The first fastening member is disposed parallel to the first plane.

2. A vacuum pump as claimed in claim 1.

4. The bottom fixing member is fastened to a fixing object by a second fastening member at a portion outside the bottom surface, The second fastening member is disposed parallel to the first plane.

2. A vacuum pump as claimed in claim 1.

5. The bottom fixing member has a through hole through which the second fastening member passes, The second fastening member is inserted into the object through the through hole, a gap between the first plane and the second plane is smaller than a gap between an inner circumferential surface of the through hole and the second fastening member; 5. A vacuum pump according to claim 4.

6. A bottom surface to be fastened to a fixed object; a side surface having a first plane formed from the bottom surface, When the bottom surface is fastened to the object, the first plane faces a second plane formed on the object. Vacuum pump.

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