Vacuum pump and vacuum pump structural part

Abstract

Provided is a vacuum pump capable of improving compression at low cost. The vacuum pump is provided with a plurality of Seebach exhaust mechanisms (60) provided with a spiral groove (62c) at a fixed circular plate (19c), the Seebach exhaust mechanisms being provided on both plate surfaces (66, 67) of the fixed circular plate (19c) on the upstream side and the downstream side, the terminal portion (62c1) of the spiral groove (62c) provided on the upstream side and the start portion (62c2) of the spiral groove (62c) provided on the downstream side being located at least at a portion of a position overlapping in the circumferential direction, and the width (Cc) of the flow path of the return portion on the upstream side and the downstream side being equal to or less than the depth (Hc) of the flow path of the Seebach exhaust mechanism.

Description

Technical Field

[0001] This invention relates to vacuum pumps, such as turbomolecular pumps, and their structural components. Background Technology

[0002] Generally, a known type of vacuum pump is the turbomolecular pump. In this turbomolecular pump, the rotor blades are rotated by energizing a motor inside the pump body, and the gas is expelled by ejecting gas molecules (process gas) drawn into the pump body.

[0003] Furthermore, among such turbomolecular pumps are Sigbarn (also known as "Sigbarn") type turbomolecular pumps (Patent Documents 1-3). In this Sigbarn type molecular pump, multiple vortex-shaped flow paths spaced apart by hill-shaped sections are formed in the gap between the rotating and fixed circular plates. Moreover, the Sigbarn type molecular pump applies tangential momentum to the gas molecules diffused into the vortex-shaped flow paths by means of the rotating circular plate, and applies a dominant directionality in the exhaust direction by means of the vortex-shaped flow paths to exhaust gas.

[0004] Patent Document 1: Japanese Patent No. 6228839.

[0005] Patent Document 2: Japanese Patent No. 6353195.

[0006] Patent document 3: Japanese Patent No. 6616560.

[0007] However, in vacuum pumps like the aforementioned Sigbarn-type molecular pump, if the combination of rotating and fixed circular plates is a single layer, the compression ratio is often insufficient, making it unusable in industrial applications. Therefore, multi-layering of the rotating and fixed circular plates improves the compression ratio. However, if the flow in the vortex channel of the preceding layer is not properly connected to the flow in the vortex channel of the following layer, momentum loss of gas molecules occurs, hindering effective compression.

[0008] Therefore, as disclosed in Patent Documents 1-3, protrusions (such as reference numeral 600 in Patent Document 1) and connecting holes (such as reference numeral 501 in Patent Document 2) are provided between the vortex-shaped flow path of the front layer and the vortex-shaped flow path of the rear layer, thereby connecting the flow of the front layer and the flow of the rear layer and preventing the loss of momentum of gas molecules. Therefore, the shapes of the rotating and fixed circular plates become complex, and the processing cost of the protrusions and connecting holes is necessary. The object of the present invention is to provide a vacuum pump and vacuum pump structural parts that can improve compressibility at a low cost. Summary of the Invention

[0009] (1) In order to achieve the above objective, the present invention is a vacuum pump having a plurality of Sigbarn exhaust mechanisms, wherein the Sigbarn exhaust mechanism is provided with a vortex-shaped groove on at least one of a rotating circular plate and a fixed circular plate, and at least a portion of the Sigbarn exhaust mechanism is provided on both the upstream and downstream sides of the rotating circular plate or the fixed circular plate. The vacuum pump is characterized in that the terminal portion of the vortex-shaped groove provided on the upstream side and the starting portion of the vortex-shaped groove provided on the downstream side are located at least partially overlapping in the circumferential direction, and the width of the flow path of the fold-back portion on the upstream side and the downstream side is equal to or less than the depth of the flow path of the Sigbarn exhaust mechanism.

[0010] (2) In addition, in order to achieve the above-mentioned objective, another feature of the present invention is that, in the vacuum pump described in (1) above, the side portion of the aforementioned vortex groove of the aforementioned terminal portion and the side portion of the aforementioned vortex groove of the aforementioned starting portion are at least partially located on the same straight line.

[0011] (3) In addition, in order to achieve the above objectives, other features of the present invention are that, in the vacuum pump described in (1) or (2) above, the aforementioned fold-back portion is formed on at least one of the outer peripheral side of the aforementioned rotating circular plate and the inner peripheral side of the aforementioned fixed circular plate.

[0012] (4) In addition, in order to achieve the above objectives, another aspect of the present invention is a vacuum pump structural component, which is used in a vacuum pump. The vacuum pump has a plurality of Sigbarn exhaust mechanisms. The Sigbarn exhaust mechanism has a vortex-shaped groove provided on at least one of a rotating circular plate and a fixed circular plate. At least a portion of the Sigbarn exhaust mechanism is provided on both the upstream and downstream sides of the rotating circular plate or the fixed circular plate. The vacuum pump structural component is characterized in that the terminal portion of the vortex-shaped groove provided on the upstream side and the starting portion of the vortex-shaped groove provided on the downstream side are located at least partially overlapping in the circumferential direction, and the width of the flow path of the folded-back portion on the upstream side and the downstream side is equal to or less than the depth of the flow path of the Sigbarn exhaust mechanism.

[0013] (5) In addition, in order to achieve the above objectives, other features of the present invention are that, in the vacuum pump structure parts described in (4) above, the side portion of the aforementioned vortex groove of the aforementioned terminal portion and the side portion of the aforementioned vortex groove of the aforementioned starting portion are at least partially located on the same straight line.

[0014] (6) In addition, in order to achieve the above objectives, other features of the present invention are that, in the vacuum pump structure parts described in (4) or (5) above, the aforementioned folded-back portion is formed on at least one of the inner and outer peripheral sides of at least one of the aforementioned rotating circular plate and the aforementioned fixed circular plate.

[0015] Invention Effects

[0016] According to the above invention, a vacuum pump and vacuum pump structural parts that can improve compressibility at low cost can be provided. Attached Figure Description

[0017] Figure 1 This is a longitudinal section of the turbomolecular pump according to an embodiment of the present invention.

[0018] Figure 2 (a) means Figure 1 (a) is an enlarged view of a portion of (b), and (b) is an enlarged view of yet another portion of (a).

[0019] Figure 3 (a) is a general representation Figure 1 (a) is an explanatory diagram of the upstream side of the fixed circular plate in the section of line AA, and (b) is an explanatory diagram that schematically shows the state of the downstream side of the fixed circular plate in (a) when viewed at an angle.

[0020] Figure 4 It is a three-dimensional diagram that shows a partially enlarged view of the inner circumference of a fixed circular plate.

[0021] Figure 5 (a) is an explanatory diagram showing the positional relationship of the mountain in an embodiment of the present invention, (b) is an explanatory diagram showing a modified example of the positional relationship of the mountain, (c) is an explanatory diagram showing another modified example of the positional relationship of the mountain, and (d) is an explanatory diagram showing yet another modified example of the positional relationship of the mountain.

[0022] Figure 6 (a) is an explanatory diagram schematically showing a portion of the simulation results of the compression effect of a fixed circular plate according to an embodiment of the present invention, and (b) is an explanatory diagram schematically showing a portion of the simulation results of the compression effect of a fixed circular plate with a conventional construction. Detailed Implementation

[0023] Hereinafter, a vacuum pump according to an embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 A Sigbarn-type turbomolecular pump (hereinafter referred to as "turbomolecular pump") 10, which is a vacuum pump according to an embodiment of the present invention, is schematically shown in longitudinal section. This turbomolecular pump 10 is connected, for example, to the vacuum chamber (not shown) of an object device such as a semiconductor manufacturing apparatus.

[0024] The turbomolecular pump 10 integrally comprises a cylindrical pump body 11 and a box-shaped electrical housing (not shown). The pump body 11... Figure 1 The upper part of the turbomolecular pump 10 is the intake section 12, which is connected to the target equipment side, and the lower part is the exhaust section 13, which is connected to the auxiliary pump (back pump, etc.). Furthermore, the turbomolecular pump 10, in addition to... Figure 1In addition to the vertical posture shown, it can also be used in inverted, horizontal, and tilted postures.

[0025] Although not shown in the diagram, the electrical housing houses a power supply circuit for supplying electricity to the pump body 11 and a control circuit for controlling the pump body 11. Furthermore, the control circuit controls various devices, including the motor 16, magnetic bearing (reference numerals omitted), and heater 48, which will be described later.

[0026] The pump body 11 has a main body cover 14, which is a generally cylindrical frame. The main body cover 14 is configured to house the pump body. Figure 1 The upper part of the intake side cover 14a, which is an intake side component, and located in Figure 1 The exhaust side cover 14b, which is an exhaust side component, is connected in series in the axial direction. Here, the intake side cover 14a is referred to as a cover, for example, and the exhaust side cover 14b is referred to as a base, for example.

[0027] The intake side shroud 14a and the exhaust side shroud 14b are radially ( Figure 1 The left and right directions overlap. Furthermore, the intake side cover 14a makes one end (in the axial direction) overlap. Figure 1 The inner circumferential surface of the lower end of the intake side cover 14a faces the outer circumferential surface of the upper end 29a of the exhaust side cover 14b. Furthermore, the intake side cover 14a and the exhaust side cover 14b are hermetically joined together by means of a plurality of bolts with hexagonal holes (not shown) through an O-ring (sealing member 41) housed in the groove.

[0028] Here, the exhaust side cover 14b can also be configured as a generally cylindrical base spacer, blocking one axial end of the base spacer. Figure 1 The base body is divided into two parts (the lower end of the base). The base spacer and the base body can also be referred to as the upper base, the lower base, etc. In addition, a heater and a water-cooled pipe for the temperature management system (TMS) can be installed at the exhaust side cover 14b.

[0029] An exhaust mechanism 15 and a rotary drive unit (hereinafter referred to as a "motor") 16 are provided inside the main body cover 14. Among them, the exhaust mechanism 15 includes a turbomolecular pump mechanism 17 as a pump mechanism. The basic structure of the turbomolecular pump mechanism 17 will be briefly described below.

[0030] exist Figure 1The turbomolecular pump mechanism 17, located on the upper side, transports gas (process gas) as a fluid using multiple turbine blades. It includes fixed circular plates (also called "fixed wing", "stator wing", etc.) 19a-19e and rotating circular plates (also called "rotor wing", "rotor wing", etc.) 20a-20e, which are radially arranged with predetermined inclination and curved surfaces. In the turbomolecular pump mechanism 17, the fixed circular plates 19a-19e and the rotating circular plates 20a-20e are arranged in multiple alternating groups (here, 5 groups).

[0031] In this embodiment, a Sigbarn-type exhaust mechanism is used, positioned between the fixed circular plates 19a-19e and the rotating circular plates 20a-20e, such as... Figure 2 (a) shows a portion enlarged, where vortex-shaped channels (vortex channels) 62a-62e are formed by multiple rectangular-shaped hills 61a-61e. Details about these hills 61a-61e and vortex-shaped channels 62a-62e will be explained later. In addition, "vortex-shaped channel" can also be called, for example, "vortex channel" or "vortex channel flow path", but hereinafter, "vortex-shaped channel" will be referred to as "channel".

[0032] Fixed circular plates 19a-19e are integrally assembled into the main body cover 14, and a layer of rotating circular plates (20a-20e) is inserted between the upper and lower layers of fixed circular plates (19a-19e). The rotating circular plates 20a-20e are integrally formed into the cylindrical rotor 28, which is concentrically fixed to the rotor shaft 21 in a manner that covers the outer side of the rotor shaft 21. Furthermore, the rotating circular plates 20a-20e rotate in the same direction as the rotor shaft 21 and the rotor 28 as the rotor shaft 21 rotates.

[0033] Here, the pump body 11 is made of aluminum alloy as the main material, and the exhaust side cover 14b, fixed circular plates 19a~19e, rotor 28, etc., are also made of aluminum alloy. Furthermore, the rotor shaft 21, various bolts (not shown), etc., are made of stainless steel. Figure 1 , Figure 2 In (a) and (b), to avoid making the drawings complicated, the section lines representing the cross-section of the pump body 11 are omitted.

[0034] The rotor shaft 21 is machined into a stepped cylindrical shape, extending from the turbomolecular pump mechanism 17 to the lower threaded groove pump mechanism 18. Furthermore, a motor 16 is disposed at the central portion of the rotor shaft 21 in the axial direction. This motor 16 will be described later.

[0035] Furthermore, at the turbomolecular pump 10, flushing gas (protective gas) is supplied into the main body cover 14. This flushing gas is used to protect the bearing components described later, the aforementioned rotating discs 20a-20e, etc., to prevent corrosion caused by process gases, and to cool the rotating discs 20a-20e. The supply of this flushing gas can be carried out using conventional methods.

[0036] For example, although the illustration is omitted, a flushing gas flow path extending radially in a straight line is provided at a predetermined location on the exhaust side cover 14b (a position approximately 180 degrees off from the exhaust port 25, etc.). Furthermore, flushing gas is supplied from the outside of the exhaust side cover 14b via a flushing gas cylinder (N2 gas cylinder, etc.), a flow regulator (valve device), etc., relative to this flushing gas flow path (more specifically, the flushing port serving as the gas inlet). The flushing gas flowing in the bearing section, etc., is then discharged outside the main body cover 14 through the exhaust port 25.

[0037] The aforementioned motor 16 has a rotating member (reference numerals omitted) fixed to the outer periphery of the rotor shaft 21, and a fixing member (reference numerals omitted) arranged to surround the rotating member. The power supply for operating the motor 16 is provided by a power circuit section and a control circuit section housed in the aforementioned electrical housing (not shown).

[0038] Regarding the support of the rotor shaft 21, a non-contact bearing based on magnetic levitation, namely a magnetic bearing, is used. As magnetic bearings, two sets of radial magnetic bearings (radial magnetic bearings) 30 are arranged above and below the motor 16, and one set of axial magnetic bearings (axial magnetic bearings) 31 is arranged at the lower part of the rotor shaft 21.

[0039] Each of these radial magnetic bearings 30 comprises a radial electromagnet target 30A formed at the rotor shaft 21, multiple (e.g., two) radial electromagnets 30B facing it, and a radial displacement sensor 30C. The radial displacement sensor 30C detects the radial displacement of the rotor shaft 21. Furthermore, based on the output of the radial displacement sensor 30C, the excitation current of the radial electromagnets 30B is controlled, and the rotor shaft 21 is levitated and supported in a manner that allows it to rotate about its axis at a predetermined radial position.

[0040] The axial magnetic bearing 31 comprises a disc-shaped armature disk 31A mounted on the lower end of the rotor shaft 21, axial electromagnets 31B facing each other vertically across the armature disk 31A, and an axial displacement sensor 31C positioned slightly away from the lower end face of the rotor shaft 21. The axial displacement sensor 31C detects the axial displacement of the rotor shaft 21. Furthermore, based on the output of the axial displacement sensor 31C, the excitation current of the vertically positioned axial electromagnets 31B is controlled, and the rotor shaft 21 is levitated and supported in a manner that allows it to rotate around its axis at a predetermined axial position.

[0041] Furthermore, by using these radial magnetic bearings 30 and axial magnetic bearings 31, the rotor shaft 21 (and rotor blades 20) will not wear during high-speed rotation, resulting in a long service life and enabling an environment without lubrication. In addition, in this embodiment, by using radial displacement sensors 30C and axial displacement sensors 31C, the rotor shaft 21 is free only in the direction of rotation (θz) about the axial direction (Z direction), allowing position control about the other five axes, namely X, Y, Z, θx, and θy.

[0042] Furthermore, radially spaced protective bearings (also called "protective bearings," "bottoming (T / D) bearings," "support bearings," etc.) 32 and 33 are arranged around the upper and lower parts of the rotor shaft 21. With the help of these protective bearings 32 and 33, even in the event of faults such as electrical system failure or atmospheric intrusion, the position and orientation of the rotor shaft 21 will not change significantly, and the rotating circular plates 20a~20e and their peripheral parts will not be damaged.

[0043] In addition, the rotor shaft 21, the rotor blade 20 that rotates integrally with the rotor shaft 21, the rotor cylindrical part 23 and the rotating part of the motor 16 (reference numerals omitted) are collectively referred to as "rotor part" or "rotating part".

[0044] Next, the aforementioned fixed circular plates 19a-19e, the mountain portions 61a-61e and the groove portions 62a-62e provided at the fixed circular plates 19a-19e will be described. First, in this embodiment, as described above, five sets of fixed circular plates 19a-19e and rotating circular plates 20a-20e are provided.

[0045] Furthermore, in this embodiment, the fixed circular plates 19a~19e and the rotating circular plates 20a~20e move from the intake section 12 side to the exhaust section 13 side (from... Figure 1 The upper and lower sides of the plate are alternately arranged in the order of rotating circular plate 20a, fixed circular plate 19a, rotating circular plate 20b, fixed circular plate 19b, ..., rotating circular plate 20e, fixed circular plate 19e.

[0046] Figure 2 (a) will Figure 1 A portion of the fixed circular plates 19a-19e and the rotating circular plates 20a-20e are shown in enlarged form. Furthermore, Figure 2 (a) will Figure 1 The right side of the turbomolecular pump mechanism 17 is shown in enlarged view. Furthermore, the fixed circular plates 19a-19e and the rotating circular plates 20a-20e are symmetrical about the axis of the main body cover 14, rotor shaft 21, etc. Figure 1 The structure is symmetrical (left and right), so only the diagram is shown here. Figure 1The right side of the image is shown; the left side is omitted from the diagram.

[0047] like Figure 2 As shown in (a), the mountain portions 61a-61e of each fixed circular plate 19a-19e are integrally formed with the fixed circular plate 19a-19e. Furthermore, from the first to the fourth fixed circular plate 19a-19d (hereinafter referred to as "intake side", "upstream side", etc.) shown from the top of the figure, the mountain portions 61a-61d are formed on both the plate surface 66 of the intake side (upstream side) and the plate surface 67 of the exhaust side (hereinafter referred to as "exhaust side", "downstream side", etc.).

[0048] Furthermore, at the fifth fixed circular plate 19e from the intake side (upstream side) (the first from the exhaust side (downstream side), a hill 61e is formed only on the plate surface 66 on the intake side (upstream side), and no hill 61e is formed on the plate surface 67 on the exhaust side (downstream side).

[0049] Hereinafter, the reference numerals on the plates 66 and 67 of each of the fixed circular plates 19a-19e are common. The common reference numerals (here, reference numerals 66 and 67) will be used to explain the different fixed circular plates 19a-19e. Furthermore, Figure 2 In (a) to avoid making the figures complicated, only the fixed circular plate 19a located on the intake side (upstream side) and the fixed circular plate 19e located on the exhaust side (downstream side) are labeled with the reference numerals for plate surfaces 66 and 67. The reference numerals for plate surfaces 66 and 67 of the other fixed circular plates 19b to 19d are omitted.

[0050] Furthermore, at each of the fixed circular plates 19a~19e on each plate surface 66, 67 (only on one plate surface 66 at the fifth fixed circular plate 19e), as shown... Figure 3 The third fixed circular plate 19c in (a) and (b) is illustrated to have multiple (here, eight) hills (here, reference numeral 61c).

[0051] here, Figure 3 (a) schematically (patternally) shows the state of the fixed circular plate 19c viewed axially from the upstream side of the plate surface 66. Furthermore, Figure 3 (b) roughly represents the state of the fixed circular plate 19c when viewed at an angle from the downstream side of the plate surface 67.

[0052] Furthermore, in this embodiment, regardless of the differences between the plate surfaces 66 and 67, the fixed circular plates 19a-19e are labeled with common reference numerals (reference numerals 61a-61e) for all the mountain-shaped parts. Similarly, the grooves 62a-62e are also labeled with common reference numerals (reference numerals 62a-62e) for all the grooves, regardless of the differences between the plate surfaces 66 and 67.

[0053] At each of the fixed circular plates 19a-19e, the mountain portions 61a-61d protrude from both sides of the circular plate-shaped main body portion (circular plate-shaped portion) 68, namely the plate surfaces 66 and 67, at defined predetermined angles. Furthermore, although detailed descriptions are omitted, in this embodiment, with respect to the first fixed circular plate 19a from the upstream side, the thickness of the main body portion 68 gradually decreases from the base end side, i.e., the outer periphery side, to the end side, i.e., the inner periphery side.

[0054] Here, "outer periphery" means the outer side of the main body 68 of the fixed circular plates 19a-19c in the radial direction, and "inner periphery" similarly means the inner side of the main body 68 in the radial direction. Furthermore, the relative rotation direction of the fixed circular plates 19a-19e and the rotating circular plates 20a-20e can also be called "tangential direction" on a straight line, and "circumferential direction" on a curve, etc.

[0055] Furthermore, regarding the 2nd to 5th fixed circular plates 19b to 19e, the thickness of the main body 68 is approximately constant. Also, regarding the 5 fixed circular plates 19a to 19e, the amount of protrusion of the mountain sections 61a to 61e from the main body 68 is not uniform but different for each.

[0056] To be more specific, the main body 68 of each fixed circular plate 19a~19e and rotating circular plate 20a~20e is not all processed to have the same thickness or uniform thickness, but is formed to have its own inherent thickness and inclination.

[0057] Furthermore, if we take the inner circumferential surface 81 of the main body 19a-19d as a reference, for example, the main body cover 14, not all of them extend from the inner circumferential surface 81 at a right angle. Moreover, the plate surface 66 on the upstream side and the plate surface 67 on the downstream side of each main body 68 are inclined at an angle less than a right angle and at an angle greater than a right angle relative to the inner circumferential surface 81.

[0058] Furthermore, in this embodiment, regarding the first and second fixed circular plates 19a and 19b from the upstream side, the protrusion of the mountain portions 61a and 61b is generally larger than the protrusion of the mountain portions 61c and 61e of the third to fifth fixed circular plates 19c to 19e. Moreover, the protrusion of the mountain portions 61c and 61e of the third to fifth fixed circular plates 19c to 19e varies from one to the other, generally decreasing towards the third to fifth plate.

[0059] Furthermore, since the protrusions of the mountain portions 61a-61e of the fixed circular plates 19a-19e differ, the axial spacing of the rotating circular plates 20a-20e that house the fixed circular plates 19a-19e also differs from the dimensions of the fixed circular plates 19a-19e. Moreover, the spacing of the rotating circular plates 20a-20e decreases from the upstream side to the downstream side.

[0060] Here, the aforementioned "dimensions of the fixed circular plates 19a~19e" can be defined, for example, as "the distance (axial distance) from the end of the mountain portion 61a~61e of one plate surface 66 to the end of the mountain portion 61a~61e of the other plate surface 67", or "the sum of the thickness of the main body portion 68 of the fixed circular plates 19a~19e and the protrusion of the mountain portions 61a~61e of the two plate surfaces 66, 67 (one of the plate surfaces 66 in the fifth fixed circular plate 19e)".

[0061] Furthermore, in this embodiment, the "size of the fixed circular plates 19a to 19e" is approximately the same (uniform) for each of the fixed circular plates 19a to 19e, from the central side near the rotor 28 to the outer peripheral side.

[0062] Furthermore, regarding the rotating circular plates 20a-20e, the thickness of each rotating circular plate 20a-20e is approximately uniform from the central side near the rotor 28 to the outer periphery. In addition, the thickness relationship between the rotating circular plates 20a-20e is approximately the same (common). Furthermore, the amount of protrusion of the rotating circular plates 20a-20e from the rotor 28 is also approximately the same (common), and the rotating circular plates 20a-20e are axially aligned with their outer periphery end faces covering the entire circumference.

[0063] Next, we will explain the mountain sections 61a-61e and the groove sections 62a-62e in more detail. Furthermore, while the fixed circular plates 19a-19e differ in shape and size from the details described above, they perform the same function in the compression principle of the gas (process gas). Therefore, we will only discuss them here. Figure 3 The relationship between a fixed circular plate (the third fixed circular plate 19c from the upstream side) shown in (a) and (b) and the surrounding rotating circular plates 20c, 20d, etc. will be explained. The description of the other fixed circular plates 19a, 19b, 19d, 19e will be omitted as appropriate.

[0064] Figure 3 As described above, the fixed circular plate 19c shown in (a) and (b) has a circular plate-shaped main body 68, a plurality of (here, eight on each side) mountain sections 61c, and a groove section 62c. Furthermore, a Sigbarn-type exhaust mechanism 60 is formed on the fixed circular plate 19c by means of the mountain sections 61c and the groove section 62.

[0065] Here, in this embodiment, the term "Sigbahn-type exhaust mechanism" can be used to refer to one slot 62c of one side of the plate 66 as a unit, or multiple slots 62c as a unit.

[0066] Furthermore, the term "Siegbarn-type exhaust mechanism" can also be used to describe an exhaust mechanism consisting of a flow path formed by two plate surfaces 66 and 67 spanning the upstream and downstream sides of a fixed circular plate 19c. Moreover, the term "Siegbarn-type exhaust mechanism" can also be used to describe an exhaust mechanism consisting of a flow path between a fixed circular plate 19c and a rotating circular plate 20b (or rotating circular plate 20d), and an exhaust mechanism consisting of multiple sets of fixed and rotating circular plates.

[0067] Furthermore, such as Figure 3 As shown in (b), on the outer periphery of the main body 68, the upright wall (spacer) 69 for fixing to the main body cover 14 is formed at a uniform height at approximately right angles to the main body 68.

[0068] Figure 3 In (b), the fixed circular plate 19c is represented as the vertical wall portion 69 extending upward from the main body portion 68, but Figure 1 , Figure 2 In (a) and (b), it is indicated that the vertical wall portion 69 extends downward from the main body portion 68. That is, Figure 3 In (b), the upstream side plate surface 66 of the main body 68 faces downward, and the downstream side plate surface 67 faces upward, but... Figure 1 , Figure 2 In (a) and (b), the upstream side plate 66 of the main body 68 faces upward, and the downstream side plate 67 faces downward.

[0069] like Figure 3 As shown in (a) and (b), the through hole 70 for the rotor 28 and the like to pass through is formed in a perfect circle at the center of the main body 68. Furthermore, the hill 61c is formed in a spiral shape at the plate surfaces 66 and 67 of the main body 68, centered on the center of the main body 68. Moreover, the hill 61c extends from the periphery of the through hole 70 to the area in front of the vertical wall 69 with a smooth curve.

[0070] here, Figure 3(a) schematically shows the state of the upstream side of the fixed circular plate 19c viewed from the front. In contrast, Figure 3 (b) schematically shows the state in which the fixed circular plate 19c is viewed at an angle from the downstream side. And, it shows the state in which the fixed circular plate 19c is viewed from the upstream side. Figure 3 In (a), the hill 61c formed on the upstream side of the plate surface 66 is represented by a solid line, while the hill 61c formed on the downstream side of the plate surface 67 is represented by a dashed line. Furthermore, Figure 3 In (a), the illustration of the vertical wall portion 69 is omitted.

[0071] The vertical wall portion 69 is installed on the main body cover 14 and forms part of the main body cover 14. Furthermore, the inner peripheral surface of the vertical wall portion 69 forms part of the inner peripheral surface 81 of the aforementioned main body cover 14. In addition, the vertical wall portion 69 is also formed on other fixed circular plates 19a, 19b, 19d, and 19e and is installed in the main body cover 14, thereby also functioning as a spacer that defines the axial spacing between the fixed circular plates 19a to 19e.

[0072] On the upstream side of the fixed circular plate 19c, on the plate surface 66, as indicated by the solid arrow Q representing the gas (process gas) transfer direction, the outer periphery of the main body 68 is the starting part 62c2 side (fluid inlet side), and the inner periphery of the main body 68 is the terminal part 62c1 side (fluid outlet side). Similarly, on the downstream side of the plate surface 67, as indicated by the dashed arrow Q representing the gas transfer direction, the inner periphery of the main body 68 is the starting part 62c2 side (fluid inlet side), and the inner periphery of the main body 68 is the terminal part 62c1 side (fluid outlet side).

[0073] here, Figure 3 In (a) and (b), arrow R indicates the direction of rotation of the rotating circular plate 20d, which represents the relative rotational displacement. Furthermore, Figure 3 In (a), to avoid making the illustration too complicated, only the cylindrical portion (rotor cylindrical portion) of the rotor 28 surrounding the outer periphery of the rotor shaft 21 is marked with a section line.

[0074] Furthermore, on the outer and inner peripheral sides of the main body 68, such as Figure 2 (b) shows a foldback section 86-88 with a spatial foldback structure having a gas flow path. First, regarding the upstream plate surface 66 of the main body 68, the foldback section 86 on the outer periphery is formed as a groove 62b spanning the downstream plate surface 67 of the second fixed circular plate 19b, a rotating circular plate (here, rotating circular plate 20c) facing the upstream side, and a groove 62c on the upstream plate surface 66 of the third fixed circular plate 19c.

[0075] Furthermore, regarding the inner circumference of the third fixed circular plate 19c, the folded-back portion 87 on the inner circumference is formed such that the groove portions 62c of the two plate surfaces 66 and 67 are spatially connected through the main body portion 68 of the fixed circular plate 19c.

[0076] Furthermore, regarding the downstream side plate surface 67 of the main body 68, the folded-back portion 88 on the outer periphery is formed as a groove 62c spanning the downstream side plate surface 67, a rotating circular plate (here, a rotating circular plate 20d) facing the downstream side, and a groove 62d on the upstream side plate surface 66 of the fourth fixed circular plate 19d.

[0077] At the folded-back portion 86 (and 87) on the outer periphery of the third fixed circular plate 19c, the end faces (hereinafter referred to as "outer end faces") 71 of the respective mountain portions 61c of the two plate surfaces 66 and 67 Figure 3 (a) and (b) protrude and protrude onto the plate surfaces 66 and 67. Furthermore, on the fixed circular plate 19c, the mountain part 61c and the groove part 62c are formed with the same phase on the upstream plate surface 66 and the downstream plate surface 67, starting from their respective starting points (starting parts).

[0078] Therefore, on the two plate surfaces 66 and 67 of the main body 68, the outer end face 71 of the mountain portion 61c protrudes in opposite directions with respect to the thickness direction of the main body 68, and is positioned at the same location with respect to the circumference of the main body 68. Furthermore, the groove portions 62c separated by the mountain portions 61c are also formed such that the terminal portion 62c1 of the groove portion 62c provided on the upstream plate surface 66 and the starting portion 62c2 of the groove portion 62c provided on the downstream plate surface 67 are located as a whole in a position that overlaps in the circumferential direction (arranged in the thickness direction of the main body 68), and are spatially continuous with each other.

[0079] Furthermore, the outer end face 71 of the mountain portion 61c faces the inner peripheral surface 81 of the main body cover 14. Also, the distance Cc between the outer end face 71 of each mountain portion 61c and the inner peripheral surface 81 of the main body cover 14 is... Figure 2 (b) Figure 3 The distance (interval) Hc between (a) and the main body 68 of the fixed circular plate 19c and the surface (the downstream plate surface 78) of the rotating circular plate (here, the rotating circular plate 20c) facing it is determined in relation to the distance (interval) between (a) and (b) and (c).

[0080] That is, the distance Cc between the outer end face 71 of each hill 61c and the inner peripheral surface 81 of the main body cover 14 can be considered as the width of the flow path of the folded-back section 87. Furthermore, the distance Hc between the main body 68 of the fixed circular plate 19c and the rotating circular plate 20c can be considered as the depth of the flow path of the Siegbahn exhaust mechanism. Hereinafter, the aforementioned distance Cc will be referred to as the "width Cc of the flow path of the folded-back section," and the height Hc of the hill will be referred to as the "depth Hc of the flow path of the Siegbahn exhaust mechanism." In addition, the depth Hc of the flow path of the Siegbahn exhaust mechanism (the distance between the main body 68 of the fixed circular plate 19c and the rotating circular plate 20c) can also be approximately described based on the height of the hill 61c.

[0081] The width Cc of the flow path of the folded-back portion is formed to the same degree as the depth Hc of the flow path of the Siegbahn exhaust mechanism, covering the entire circumference of the fixed circular plate 19c. The depth Hc of the flow path of the Siegbahn exhaust mechanism mentioned here is taken as the height of the outer end face 71 of the hill 61c (the amount of protrusion from the plate surface 66 on the upstream side).

[0082] Furthermore, the depth Hc of the flow path in the Siegbahn exhaust mechanism is a value in the range of approximately 2 to 3 mm (e.g., 2 mm), and the width Cc of the flow path in the return section is the same as (equivalent to) the depth Hc of the flow path in the Siegbahn exhaust mechanism (e.g., 2 mm). Here, the present invention is not necessarily limited to the same value; as long as the effective compression effect described below is obtained, for example, Hc can be set to 3 mm and Cc can be set to 2 mm, etc.

[0083] By implementing such a structure, compared to the case where a protrusion is provided at the folded portion as described in, for example, Patent Document 3 mentioned above, it is possible to suppress the local pressure rise, and thus the effect of reducing the product can also be expected.

[0084] Furthermore, the present invention is not limited to the Siegbahn exhaust mechanism having a constant depth Hc in the width direction (circumferential or tangential) and the same depth Hc as the width Cc of the flow path of the return section. For example, as long as the same compression effect can be obtained, the Siegbahn exhaust mechanism can also be configured to have a varying depth Hc in the width direction (circumferential or tangential), consistent only with a portion of the depth (Hc).

[0085] Furthermore, in this embodiment, the mountain portion 61c protruding from the two plate surfaces 66 and 67 of the main body portion 68 has its end surface 76 extending along its entire length and facing the upstream rotating circular plate 20c and the upstream rotating circular plate 20d, respectively. Moreover, the distance between the end surface 76 of the mountain portion 61c and the upstream rotating circular plate 20c (reference numerals omitted) is approximately 1 mm.

[0086] Furthermore, during the operation of the turbomolecular pump 10, due to thermal expansion, the width Cc of the flow path in the return section and the distance between the end face 76 of the hill 61c and the rotating circular plate 20c on the upstream side (reference numerals omitted) change. In addition, the depth Hc of the flow path in the Siegbahn exhaust mechanism also changes due to thermal expansion.

[0087] Next, the inner circumference (inner side in the normal direction) of the main body 68 will be explained. Figure 4 The diagram is partially enlarged and schematically shown. The end face (hereinafter referred to as the "inner end face") 72 of the central side of the main body 68 of each of the two mountain parts 61c on the two plates 66 and 67 is smoothly connected to the inner peripheral surface (also referred to as the "inner peripheral surface of the main body 68") 73 of the through hole 70 without any steps. Furthermore, the inner end faces 72 of the two mountain parts 61c and the inner peripheral surface 73 of the annular main body 68 form a smooth and continuous cross-shaped curved surface, i.e., a continuous surface 74.

[0088] in addition, Figure 4 The image only indicates one location, but continuous surfaces 74 are also formed at the inner end faces 72 of other mountain sections 61c. Furthermore, in this embodiment, there are eight continuous surfaces 74 at the fixed circular plate 19c.

[0089] Furthermore, on each continuous surface 74, the inner end face 72 of the mountain portion 61c (first mountain portion) of the upstream side plate surface 66 and the inner end face 72 of the mountain portion 61c (second mountain portion) of the downstream side plate surface 67 are arranged such that at least a portion of them are on the same straight line with respect to the thickness direction of the main body portion 68.

[0090] The term "at least partially lying on the same straight line" as used here can be considered in various ways, as will be discussed later. For example, Figure 5 In (a), as an example, a portion of the inner periphery of the main body 68 (the portion facing the through hole 70) is shown schematically with an enlarged view of the outer periphery (from the inside to the outside in the normal direction) when viewed from the inner periphery side. This illustrates how the side surfaces (sides of the vortex grooves) 75 of the two hillsides 61c are located on the same straight line (on the straight line S) in the thickness direction of the main body 68. Figures 1-3 In the embodiment shown, this method is adopted.

[0091] However, the phrase "at least partly on the same straight line" is not limited to this; for example, ... Figure 5 As shown in (b), it can be illustrated that the side surfaces 75 of the two mountain portions 61c are not located on the same straight line (on the straight line S) in the thickness direction of the main body portion 68, but are partially located on a common straight line (on the straight line T).

[0092] In addition, for example, Figure 5As shown in (c), it is possible to move the positions of the two mountain sections 61c left and right in the circumferential direction by the amount of thickness (also referred to as "offset", "bias", etc.), such that the side surface (side of the vortex groove) 75B of one side of the given mountain section 61c and the side surface (side of the vortex groove) 75A of the mountain section 61c protruding to the opposite side are located on a common straight line (on the straight line U). This can be expressed, for example, as such that the side surface (or edge) of the opposite mountain section 61c at a diagonal position is in the same phase in the circumferential direction of the fixed circular plate 19c.

[0093] Furthermore, such as Figure 5 As shown in (d), it is also possible to consider having different thicknesses for the two mountain sections 61c. Furthermore, in such a case, for example, it is possible to consider a situation where one side 75A is located on the same straight line (on the straight line S) but the other side 75B is not located on the same straight line (on the straight line S).

[0094] Furthermore, although the illustration is omitted, the outer periphery of the plate surface 67 on the downstream side of the third fixed circular plate 19c and the outer periphery of the plate surface 66 on the upstream side of the fourth fixed circular plate 19d are also arranged such that "at least a portion of the outer end face 71 of the mountain portion 61c (first mountain portion) of the third fixed circular plate 19c and the outer end face 71 of the mountain portion 61d (second mountain portion) of the fourth fixed circular plate 19d are located on the same straight line.

[0095] As for the positional relationship of their outer end faces 71, 71, the same as described above is adopted. Figure 5 The same method as the mountain part 61c in (a). Furthermore, not limited to this, it is possible to use the same method as described above. Figure 5 The same way as the mountain part 61c of (b)~(d).

[0096] If we were to describe in more detail the grooves 62c that are spaced apart by such hills 61c, then as... Figure 3 As shown in (a) and (b), on each plate surface 66, 67, the outer periphery becomes relatively wider (larger opening width). Furthermore, the inner periphery of the groove 62c becomes relatively narrower (smaller opening width). Moreover, the groove 62c is separated by two hills 61c on each plate surface 66, 67, forming a vortex shape centered on the center of the main body 68.

[0097] As previously described, the groove 62c is formed to be spatially continuous with the same phase at the two plate surfaces 66 and 67 of the main body 68. Furthermore, the second fixed circular plate 19b and the third fixed circular plate 19c are also continuous via the aforementioned fold-back portion 86. Moreover, the groove 62c formed on the upstream plate surface 66 and the groove 62c formed on the downstream plate surface 67 of the third fixed circular plate 19c are continuous via the fold-back portion 87. Furthermore, the third fixed circular plate 19c and the fourth fixed circular plate 19d are continuous via the fold-back portion 88.

[0098] When the turbomolecular pump 10 with this configuration operates, the aforementioned motor 16 is driven, causing the rotating circular plates 20a-20e to rotate. Furthermore, relative rotational displacement occurs between each fixed circular plate 19a-19e and each rotating circular plate 20a-20e. Figure 1 , Figure 2 As shown by multiple arrows Q (only for a portion of the attached figures), gas (process gas) is drawn from the suction section 12, and the upstream side plate surface 66 of each fixed circular plate 19a~19e is designated as the upstream region, and the downstream side plate surface 66 is designated as the upstream region, and the gas is transferred between the opposing rotating circular plates 20a~20e.

[0099] This gas transfer occurs simultaneously with the collision of gas molecules with fixed circular plates 19a-19e and rotating circular plates 20a-20e. Furthermore, the gas, which is compressed during the transfer, enters the exhaust port 25 from the exhaust section 13 and is discharged from the pump body 11 through the exhaust port 25.

[0100] Specifically, the gas drawn from the intake section 12 passes between the first rotating circular plate 20a and the first fixed circular plate 19a, between the first fixed circular plate 19a and the second rotating circular plate 20b, between the second rotating circular plate 20b and the second fixed circular plate 19b, and between the second fixed circular plate 19b and the third rotating circular plate 20c, reaching the third fixed circular plate 19c. Furthermore, the gas reaching the third fixed circular plate 19c passes between the third fixed circular plate 19c and the fourth rotating circular plate 20d, and between the fourth rotating circular plate 20d and the fifth fixed circular plate 19e, and is discharged towards the exhaust section 13.

[0101] Furthermore, taking the third fixed circular plate 19c as an example, the gas being transferred is introduced from the outer periphery into the groove 62c at the plate surface 66 on the upstream side of the fixed circular plate 19c. Then, the gas introduced into the groove 62c is transferred from the outer periphery of the main body 68 to the inner periphery.

[0102] As previously described, the groove 62c has a relatively larger width on its outer periphery and a relatively narrower width on its inner periphery. Furthermore, on the upstream plate surface 66, the groove 62c is divided by the hill 61c, gradually narrowing from the fluid inlet side (starting part 62c2, i.e., the outer periphery) to the fluid outlet side (ending part 62c1, i.e., the inner periphery). Moreover, the groove 62c is also divided by a third rotating circular plate 20c near the hill 61c, with a slight gap (the aforementioned interval of approximately 1 mm).

[0103] Furthermore, on the upstream side of the plate surface 67, the groove 62c is divided by the hill 61c, gradually narrowing from the fluid inlet side (starting part 62c2, i.e., the inner circumference side) to the fluid outlet side (ending part 62c1, i.e., the outer circumference side). Moreover, the groove 62c is also divided by a fourth rotating circular plate 20d near the hill 61c with a slight gap (the aforementioned interval of approximately 1 mm).

[0104] like Figure 2 (b) Figure 3 As shown in (a), on the downstream side of the third fixed circular plate 19c, on the plate surface 67, at the end portion 62c1 of the groove portion 62c, the outer end face 71 of the mountain portion 61c has a flow path of a fold-back portion (88) with a width Cc that faces the inner peripheral surface 81 of the main body cover 14. Furthermore, the groove portion 62c is spatially connected to the fold-back portion 88 connected to the fourth fixed circular plate 19d through the space of the flow path of the fold-back portion (88) with a width Cc, so that the exhaust function is not interrupted.

[0105] Therefore, with the relative rotational displacement between the fixed circular plate 19c and the rotating circular plate 20c, gas is introduced into the groove 62c. Inside the groove 62c, the rotating circular plate 20c applies tangential momentum to the diffused gas molecules. Furthermore, the groove 62c applies a dominant directional position to the gas molecules in the exhaust direction, thus facilitating exhaust.

[0106] Furthermore, on the outer periphery of the downstream plate surface 67, the gas transfer direction is reversed by the inner periphery surface 81 of the main body cover 14, and the gas is transferred to the groove 62d of the upstream plate surface 66 of the lower layer fixed circular plate (here, fixed circular plate 19d).

[0107] With the help of the turbomolecular pump 10 constructed in this way, the following can be obtained Figure 6 Simulation results of the pressure distribution shown in (a). Figure 6 (a) schematically illustrates the pressure distribution on a portion of the downstream surface 67 of the fixed circular plate 19c, magnified. Furthermore, Figure 6 The simulation results of (a) will be obtained by mapping the color image obtained by computer calculation, and the boundary parts of each pressure region in the original color image that are distinguished by color will be represented by solid lines.

[0108] The pressure distribution is such that the outer periphery of the downstream plate 67 is relatively high, while the inner periphery is relatively low. Figure 6 In (a), for a groove 62c, the boundaries of the pressure regions are schematically depicted with black and white lines, and each pressure region is labeled with reference numerals Pc1 to Pc13. Therefore, the pressure in the region shown as Pc1 is the lowest, and the pressure gradually (in stages) increases in the order of Pc1, Pc2, ..., Pc12, Pc13. Furthermore, the pressure regions (Pc2 to Pc12) between the pressure regions Pc1 and Pc13 at both ends, which are roughly parallelogram-shaped or trapezoidal in shape, are represented with approximately equal widths.

[0109] The shape (projected shape) of the pressure region Pc13 located at the outermost peripheral position can be represented as a wedge shape with a sharp outer peripheral end. As described above, this wedge-shaped pressure region Pc13 is the region of maximum pressure on the downstream surface 67 of the fixed circular plate 19c (maximum pressure region), and all the grooves 62c are similarly represented. Furthermore, this maximum pressure region Pc13 reaches the position of the fold-back portion 88 formed between the inner peripheral surface 81 of the main body cover 14 and the fourth fixed circular plate 19d, which is the lower layer.

[0110] Therefore, due to the presence of the maximum pressure region Pc13 of this wedge, in the turbomolecular pump 10 of this embodiment, the gas in the groove 62c does not experience a pressure drop due to the opening at the retraction portion 88, and is supplied to the groove 62d of the plate surface 66 on the upstream side of the fixed circular plate 19d in the lower layer. Furthermore, Figure 6 In (a), to prevent the diagram from becoming too complex, the pressure distribution is shown only for one slot 62c, but in the simulation results, the same pressure distribution is obtained for all other slots 62c.

[0111] In contrast, Figure 6 (b) represents the simulation results of the previous construction. Furthermore, Figure 6 In (b), the inner diameter of the main body cover 114 is used as the... Figure 6 The dimensions of the main body cover 14 of (a) are approximately the same as those of the inner diameter.

[0112] In Figure 6 In the conventional configuration shown in (b), the gas is also gradually compressed from the inner circumference to the outer circumference. However, the distance (corresponding to the width of the flow path of the folded-back portion) Cc0 between the outer end face 171 of the mountain portion 161c of the fixed circular plate 119c and the inner circumference surface 181 of the main body cover 114 is about 10 mm, which is about 5 times the width Cc (e.g., 2 mm) of the aforementioned embodiment.

[0113] Furthermore, in the pressure distribution of the previous structure, the maximum pressure region Pc100 is located in the area very close to the outer end face 171 of the mountain 161c (the area closer to the inner circumference). This maximum pressure region Pc100 is related to... Figure 6 The shape of the wedge-shaped maximum pressure region Pc13 shown in (a) of this embodiment is different. Furthermore, on the outside of the maximum pressure region Pc100, an area (pressure drop region) Pc101 is generated facing the inner peripheral surface 181 of the main body cover 114, where the pressure drops compared to the maximum pressure region Pc100.

[0114] Therefore, in conventional structures, gas molecules disperse at the downstream end (equivalent to the terminal section) of the groove 162c, resulting in decreased exhaust and compression effects. Furthermore, the "dominant momentum in the exhaust direction" applied to the gas at the groove 162c is more easily lost at the terminal section of the groove 162c compared to this embodiment. Here, "dominant momentum in the exhaust direction" refers to the momentum applied to the gas molecules at the groove 162c that makes it dominant in the exhaust direction (terminal section direction).

[0115] According to the turbomolecular pump 10 of this embodiment as described above, for example, a wedge-shaped maximum pressure region Pc13 is formed at the end portion 62c1 (the end on the fluid outlet side) of the groove portion 62c at the downstream side of the fixed circular plate 19c. Therefore, it is possible to prevent the gas pressure from dropping before the gas flows into the lower groove (here, the groove 62d on the upstream side of the fourth fixed circular plate 19c). Furthermore, gas compression can be performed effectively while preventing pressure loss, and a high compression ratio can be maintained.

[0116] Furthermore, compared to vacuum pumps that improve compressibility by setting protrusions (such as reference numeral 600 in Patent Document 1) and connecting holes (such as reference numeral 501 in Patent Document 2) as disclosed in the aforementioned prior patent documents 1 to 3, there is no need to process protrusions and connecting holes, and high compressibility can be achieved at a low cost.

[0117] Furthermore, according to the turbomolecular pump 10 of this embodiment, during operation, due to thermal expansion, the gap Cc between the mountain 61c and the main body cover 14 further decreases depending on the situation, and the compression performance is improved in this case.

[0118] Furthermore, based on the technical concept of determining the width of the flow path of the turnaround section (the distance between the hill 61c and the main body cover 14) Cc using the flow path depth Hc of the Siegbahn exhaust mechanism as a reference, a clear guideline can be provided for determining the width Cc. Moreover, the development and design of the turbomolecular pump 10 do not require repeated trial and error, thus shortening the development and design periods.

[0119] Here, the maximum pressure region Pc13 that forms the aforementioned wedge shape can also be explained as follows. For example, if the width Cc of the flow path of the return section is like... Figure 6 (b) If the width Cc is set to about 10 mm as in the conventional configuration shown, this width becomes too large compared to the distance (e.g., less than 1 mm) between the end face 76 of the mountain 61c and the rotating circular plate 20d on the downstream side. Furthermore, gas molecules tend to diffuse on the outer periphery of the groove 62c, and the pressure drop at the return section 88 becomes greater.

[0120] However, as shown in this embodiment, the width Cc of the flow path in the return section is determined based on the depth Hc of the flow path in the Siegbahn exhaust mechanism, so that the width Cc and the depth Hc are the same. Therefore, the airtightness between the near groove 62c and the downstream-facing rotating disc 20d can also be ensured regarding the width Cc of the flow path in the return section. As a result, a wedge-shaped pressure region is formed at the fluid outlet end (terminal 62c1) of the groove 62c, achieving good compressibility.

[0121] Furthermore, in this embodiment, the rotor shaft 21 is maintained by means of the protective bearings 32 and 33, so even if the gap Cc between the mountain 61c and the main body cover 14 narrows, the gap Cc can be easily ensured.

[0122] Furthermore, according to the turbomolecular pump 10 of this embodiment, such as Figure 5 As shown in (a), the mountain 61c protrudes from the upstream side plate surface 66 and the downstream side plate surface 67 of the fixed circular plate 19c, respectively. Furthermore, at the fluid outlet side end of the groove 62c (here, the outer peripheral side end), the mountain 61c (first mountain) of the upstream side plate surface 66 and the mountain 61c (second mountain) of the downstream side plate surface 67 are arranged to be on the same straight line (on the straight line S) in the thickness direction of the main body 68.

[0123] Therefore, the fold-back portion 87 on the inner circumference side of the third fixed circular plate 19c can effectively transfer the gas compressed by the upstream plate surface 67 to the downstream plate surface 67 while preventing pressure loss.

[0124] Furthermore, the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit of the invention. For example, the description here focuses on the third fixed circular plate 19c. Moreover, various configurations described so far can be used only with respect to the third fixed circular plate 19c.

[0125] However, this is not the only possibility; the same structure can also be used for some or all of the other fixed circular plates (here, the first, second, and fourth fixed circular plates 19a, 19b, and 19d). Furthermore, a relationship can be established between the width (Ca, Cb, Cd (not shown)) of the flow path of the folded-back section and the depth (Ha, Hb, Hd (not shown)) of the corresponding Siegbahn exhaust mechanism, and this relationship can be set to be the same (or at least partially the same) as the aforementioned width Cc and depth Hc.

[0126] Furthermore, the structure of the invention of this application can also be used only with respect to one surface of a fixed circular plate (e.g., the downstream surface 67 of the third fixed circular plate 19c, etc.).

[0127] Furthermore, the relationship between the width Cc of the flow path of the folded-back portion and the depth Hc of the flow path of the Siegbahn exhaust mechanism, as described above, can also be applied to the inner circumferential side of the fixed circular plate 19c. That is, the folded-back portion can be formed on at least one of the outer circumferential side of the rotating circular plate and the inner circumferential side of the fixed circular plate. Moreover, when the relationship between the width Cc and the depth Hc is applied to the inner circumferential side of the fixed circular plate 19c, the interval between the aforementioned continuous surface 74 and the outer circumferential surface (reference numerals omitted) of the rotor 28 can be established with respect to the height of the inner end face 72 of the hill 61c, and set to approximately 2 to 3 mm in a manner that makes them at least partially the same.

[0128] Furthermore, it is possible to reduce the width of the flow path of such a fold-back section only on the outer peripheral side (or only on the inner peripheral side), or to use it in combination on the outer peripheral side and the inner peripheral side.

[0129] Furthermore, the objects forming the mountain portion 61c and the groove portion 62c are not limited to a fixed circular plate (here, fixed circular plate 19c), but can also be a rotating circular plate. Furthermore, it is also possible to mix fixed circular plates and rotating circular plates with the mountain portion 61c and the groove portion 62c formed thereon. For example, the mountain portion 61c and the groove portion 62c can be formed on one surface of the rotating circular plate and one surface of the fixed circular plate, respectively. Furthermore, the mountain portion 61c and the groove portion 62c can be provided only on one side of the fixed circular plate facing the rotating circular plate, which is separated from the rotating circular plate by the upper and lower (upstream and downstream) sides.

[0130] Furthermore, the exhaust mechanism 15 can be configured as a composite component consisting of a turbomolecular pump mechanism 17 as a pump mechanism and a threaded groove pump mechanism (not shown) as a threaded groove exhaust mechanism. In this case, various general components can be used as the threaded groove pump mechanism (not shown).

[0131] For example, the grooved pump mechanism (not shown) can include a rotor cylindrical section (not shown) and a threaded stator (not shown). Furthermore, as the rotating discs 20a-20e rotate, gas is transferred towards the grooved pump mechanism (not shown). In the grooved pump mechanism (not shown), the gas is compressed, and the compressed gas enters the exhaust port 25 from the exhaust section 13, and can be discharged from the pump body 11 through the exhaust port 25.

[0132] Explanation of reference numerals in the attached figures

[0133] 10. Turbomolecular pump (vacuum pump)

[0134] 14 main body cover

[0135] 19c Third fixed circular plate

[0136] 20d, 4th rotating circular plate

[0137] 28 rotors

[0138] 60 Sigbarn exhaust system

[0139] 61c Yamabe

[0140] 62c vortex-shaped groove (vortex-shaped groove)

[0141] The end portion of the 62c1 vortex-shaped groove

[0142] The beginning of the 62c2 vortex-shaped groove section

[0143] 66. The upstream side panel of the main body (upstream side surface)

[0144] 67. The downstream side panel of the main body (the downstream side surface)

[0145] 68 main body

[0146] 71. The outer end face of the mountain (the end face of the mountain)

[0147] 72. Inner end face of the mountain (end face of the mountain)

[0148] Side views of mountains 75, 75A, and 75B (side views of the vortex-shaped grooves)

[0149] 81. Inner circumferential surface of the main body cover (circumferential surface of opposing parts)

[0150] 87 Turnback

[0151] Width of the flow path in the Cc return section

[0152] The depth of the flow path in the Hc Sigbarn exhaust system.

Claims

1. A vacuum pump comprising a plurality of Sigbarn exhaust mechanisms, wherein each Sigbarn exhaust mechanism has a vortex-shaped groove on at least one of a rotating circular plate and a fixed circular plate. At least a portion of the aforementioned Sigbarn exhaust mechanism is disposed on both the upstream and downstream sides of the aforementioned rotating circular plate or the aforementioned fixed circular plate, and the aforementioned vacuum pump is characterized in that... The terminal portion of the vortex-shaped groove provided on the upstream side and the starting portion of the vortex-shaped groove provided on the downstream side are located at least partially overlapping in the circumferential direction. The width of the flow path at the aforementioned upstream and downstream turnaround points is set to be consistent with the depth of at least a portion of the flow path of the aforementioned Siegbahn exhaust mechanism, based on the depth of the flow path. The amount of protrusion of the mountain portion varies among the aforementioned fixed circular plates. The spacing between the aforementioned rotating discs decreases from the upstream side to the downstream side.

2. The vacuum pump as described in claim 1, characterized in that, The side portion of the aforementioned vortex-shaped groove of the aforementioned terminal portion and the side portion of the aforementioned vortex-shaped groove of the aforementioned starting portion are at least partially located on the same straight line.

3. The vacuum pump as described in claim 1 or 2, characterized in that, The aforementioned folded portion is formed on at least one of the outer peripheral side of the aforementioned rotating circular plate and the inner peripheral side of the aforementioned fixed circular plate.

4. A vacuum pump structural component, wherein the vacuum pump structural component is used in a vacuum pump, the vacuum pump having a plurality of Sigbarn exhaust mechanisms, wherein the Sigbarn exhaust mechanism has a vortex-shaped groove on at least one of a rotating circular plate and a fixed circular plate. At least a portion of the aforementioned Sigbarn exhaust mechanism is disposed on both the upstream and downstream sides of the aforementioned rotating circular plate or the aforementioned fixed circular plate, and the aforementioned vacuum pump structural component is characterized in that... The terminal portion of the vortex-shaped groove provided on the upstream side and the starting portion of the vortex-shaped groove provided on the downstream side are located at least partially overlapping in the circumferential direction. The width of the flow path at the aforementioned upstream and downstream turnaround points is set to be consistent with the depth of at least a portion of the flow path of the aforementioned Siegbahn exhaust mechanism, based on the depth of the flow path. The amount of protrusion of the mountain portion varies among the aforementioned fixed circular plates. The spacing between the aforementioned rotating discs decreases from the upstream side to the downstream side.

5. The vacuum pump structural component as described in claim 4, characterized in that, The side portion of the aforementioned vortex-shaped groove of the aforementioned terminal portion and the side portion of the aforementioned vortex-shaped groove of the aforementioned starting portion are at least partially located on the same straight line.

6. The vacuum pump structural component as described in claim 4 or 5, characterized in that, The aforementioned folded portion is formed on at least one of the outer peripheral side of the aforementioned rotating circular plate and the inner peripheral side of the aforementioned fixed circular plate.

Images