Vacuum pump and rotor and rotary wing for vacuum pump

Abstract

The present invention provides a vacuum pump and a rotor and a rotary blade for the vacuum pump, which break at a predetermined position in a predetermined state when a torque exceeding the assumed torque for rotating the rotor in the rotation direction of the rotor is generated, thereby exhibiting cheap and stable impact absorption. A vacuum pump (10) comprises a shell (11), a stator, and a rotor (17), wherein the shell (11) is formed with an air intake port or an air exhaust port, the stator is arranged on the inner side of the shell (11), the rotor (17) is built into the shell (11), the rotor (17) has a shaft (20) and a rotating wing (19), the shaft (20) is rotatably supported on the stator (18), the rotating wing (19) is provided with a plurality of sheets (22) in a multi-layered manner on the outer periphery, is formed into a cylindrical shape, and is fixed to the shaft (20) so as to be rotatable as a whole, and the vacuum pump (10) is characterized in that a fracture site limiting groove (32) as a fracture site limiting mechanism is provided on the rotating wing (19), the fracture site limiting groove (32) locally reduces the rigidity of the rotating wing (19), and limits the fracture site of the rotating wing (19).

Description

Technical Field

[0001] The present invention relates to a vacuum pump and a rotor and a rotary blade therefor, for example, to a vacuum pump for exhausting a vacuum container and a rotor and a rotary blade therefor. Background Art

[0002] Vacuum pumps used for exhaust of semiconductor manufacturing equipment and vacuum containers requiring high vacuum such as electron microscopes often use the following structure: a molecular pump mechanism and a threaded groove pump mechanism provided downstream of the molecular pump mechanism are integrally housed in a housing having an air intake port and an air exhaust port.

[0003] A rotor that is rotatably supported and can be rotated at high speed by a motor unit and a stator that is fixed to the housing of the vacuum pump are provided inside the housing of the vacuum pump.

[0004] The molecular pump mechanism rotates at high speed, and the rotor and the stator perform exhaust function. Due to this exhaust function, gas is sucked from the air intake port on the molecular pump mechanism side and exhausted to the thread groove pump mechanism side provided with the exhaust port.

[0005] The screw groove type pump mechanism is composed of a cylindrical portion formed on the lower end side of the rotor, an internal thread portion provided on the outer peripheral surface of the cylindrical portion and having a spiral groove on the outer surface, and a screw groove spacer provided on the inner peripheral surface side of the shell at a predetermined distance from the internal thread portion and having a spiral groove corresponding to the spiral groove of the internal thread portion on the inner surface. The directions of the spiral groove of the internal thread portion and the spiral groove of the screw groove spacer are such that the gas is sent toward the exhaust port when the gas is sent in the spiral groove along the rotation direction of the rotor, and the depth of the spiral groove becomes shallower as it approaches the exhaust port, and the gas sent in the spiral groove is compressed as it approaches the exhaust port.

[0006] Therefore, the gas exhausted from the molecular pump mechanism is sent to the thread groove type pump mechanism, compressed in the thread groove type pump mechanism, and exhausted to the outside of the housing from the exhaust port.

[0007] However, if a problem occurs during the operation of the vacuum pump and the rotor collides with the stator or other fixed components in the vacuum, the angular motion of the rotor is transmitted to the stator and fixed components, causing the rotor to instantly generate a large torque in the direction of rotation, while also applying greater stress to the vacuum pump as a whole.

[0008] Therefore, various proposals have been made for absorbing the impact due to such torque (for example, refer to Patent Documents 1, 2, and 3).

[0009] The vacuum pumps disclosed in Patent Documents 1, 2, and 3 are provided with a device for buffering torque generated when torque is generated to rotate the turbomolecular pump in the rotation direction of the rotor. However, the buffer device fails to absorb the torque and thus causes damage.

[0010] Patent document 1: Japanese Patent Application Laid-Open No. 10-274189.

[0011] Patent document 2: Japanese Patent Application Laid-Open No. 08-114196.

[0012] Patent document 3: Japanese Patent No. 4484470.

[0013] However, as shown in the technologies disclosed in Patent Documents 1, 2, and 3, when the rotor instantaneously generates a large torque in the rotation direction and the buffer device cannot absorb the large stress applied to the vacuum pump as a whole, unexpected parts of the vacuum pump may be damaged in unexpected forms.

[0014] Therefore, in order to improve the safety of the vacuum pump, it is obviously necessary to improve the mounting strength of the flange of the vacuum pump and the flange of the vacuum container, and it is also necessary to improve the mechanical strength of the vacuum pump as a whole. Therefore, there is a problem of increased manufacturing cost.

[0015] Furthermore, since an unexpected part of the vacuum pump may be damaged in an unexpected manner, it is difficult to take countermeasures when a problem occurs. Therefore, there is a problem that a long time is required to deal with the problem when it occurs. Summary of the invention

[0016] Therefore, a technical problem arises in order to provide a vacuum pump and a rotor and a rotating blade for a vacuum pump having the following structure. The purpose of the present invention is to solve the problem. The above-mentioned structure is that when a torque exceeding the assumed torque for rotating the rotor in the rotation direction of the rotor is generated, a predetermined portion breaks in a predetermined state, thereby exerting cheap and stable impact absorption.

[0017] The present invention is proposed to achieve the above-mentioned purpose. The invention recorded in technical solution 1 provides a vacuum pump, wherein the vacuum pump comprises a shell, a fixing part, and a rotor, wherein the shell is formed with an air intake port or an air exhaust port, the fixing part is arranged on the inner side of the shell, the rotor is built into the shell, the rotor has a shaft and a rotating wing, the shaft is rotatably supported on the fixing part, the rotating wing is provided with a plurality of sheets in a multi-layered manner on the outer periphery to form a cylindrical shape, and is fixed to the shaft so as to be rotatable as a whole, and is characterized in that a fracture portion limiting mechanism is provided on the rotating wing, and the fracture portion limiting mechanism locally reduces the rigidity of the rotating wing and limits the fracture portion of the rotating wing.

[0018] According to this structure, when a torque exceeding the assumed value is generated and applied to the rotor, the part of the fracture part limiting mechanism provided on the rotor's rotating blade is fractured into a predetermined shape, etc., to absorb the impact of the torque. That is, the predetermined part of the vacuum pump is fractured in a predetermined state, so that the post-fracture treatment can be simply performed according to a predetermined process. As a result, the maintenance work can be stabilized and the treatment can be performed at a low cost.

[0019] The invention described in Technical Solution 2 provides a vacuum pump, wherein the vacuum pump is, in the structure described in Technical Solution 1, the fracture portion limiting mechanism is a groove provided on the outer peripheral surface of the rotary blade along the axial direction of the rotary blade between the axially adjacent pieces.

[0020] According to this structure, the fracture site limiting mechanism is provided as a groove on the outer peripheral surface of the aforementioned rotary wing along the axial direction of the rotary wing between the adjacent sheets in the axial direction. By providing this groove, the part of the rotary wing provided with the groove is thinner than other parts without the groove, and the mechanical strength is reduced. As a result, when a torque exceeding the assumed value is generated and the torque is applied to the rotor, the part of the outer peripheral surface of the rotary wing provided with the groove in the axial direction is broken in a predetermined state in the axial direction, and the impact caused by the torque is absorbed. That is, the predetermined part of the vacuum pump is broken in a predetermined state, so the post-fracture processing can be simply carried out according to a determined process. As a result, the maintenance work can be stabilized and the processing can be carried out inexpensively.

[0021] The invention described in claim 3 provides a vacuum pump, wherein the vacuum pump is, in the structure described in claim 1 or 2, the fracture portion limiting mechanism is a groove provided on the inner peripheral surface of the rotary blade along the axial direction of the rotary blade.

[0022] According to this structure, the fracture site limiting mechanism is provided as a groove on the inner circumferential surface of the rotary blade along the axial direction of the rotary blade. By providing the groove, the part of the rotary blade provided with the groove is thinner than other parts without the groove, and the mechanical strength is reduced. As a result, when a torque exceeding the assumed value is generated and the torque is applied to the rotor, the part of the inner circumferential surface of the rotary blade provided with the groove along the axial direction breaks in a predetermined state along the axial direction, and absorbs the impact caused by the torque. That is, the predetermined part of the vacuum pump breaks in a predetermined state, so the post-fracture processing can be simply performed according to a determined process. As a result, the maintenance work can be stabilized and the processing can be performed inexpensively.

[0023] The invention described in Technical Solution 4 provides a vacuum pump, wherein the vacuum pump is, in the structure described in Technical Solution 1, 2 or 3, the fracture portion limiting mechanism is a groove arranged along the circumferential direction of the rotating blade on at least one of the outer circumferential surface or the inner circumferential surface of the rotating blade.

[0024] According to this structure, the fracture site limiting mechanism is provided with a groove in at least one of the outer circumferential surface or inner circumferential surface of the rotary wing along the circumferential direction of the rotary wing. By providing the groove, the part of the rotary wing provided with the groove is thinner than other parts not provided with the groove, and the mechanical strength is reduced. As a result, when a torque exceeding the assumed value is generated and the torque is applied to the rotor, the part of the rotary wing provided with the groove in at least one of the outer circumferential surface or inner circumferential surface along the circumferential direction of the rotary wing is fractured in a predetermined state along the circumferential direction of the rotary wing, absorbing the impact caused by the torque. That is, the predetermined part of the vacuum pump is fractured in a predetermined state, so the post-fracture processing can be simply performed according to a determined process. As a result, the maintenance operation can be stabilized and the processing can be performed inexpensively.

[0025] The invention described in claim 5 provides a vacuum pump, wherein, in the structure described in claim 2, 3 or 4, the groove is provided corresponding to a plurality of bolt holes provided in the rotor blade for mounting the rotor blade on the shaft.

[0026] According to this structure, the groove as the fracture site limiting mechanism is provided corresponding to the shaft and the multiple bolt holes fixed by bolts. The portion provided with the groove and the portion provided with the bolt hole are fragile compared with other portions and the mechanical strength is reduced. As a result, when a torque exceeding the assumed value is generated and the torque is applied to the rotor, the groove and the portion where the groove is connected to the bolt hole are broken in a predetermined state to absorb the impact caused by the torque. That is, the predetermined portion of the vacuum pump is broken in a predetermined state, so the post-fracture processing can be simply performed according to a determined process. As a result, the maintenance operation can be stabilized and the processing can be performed inexpensively.

[0027] The invention described in technical solution 6 provides a rotor, wherein the rotor is rotatably mounted on a fixed portion provided on the inner side of a shell of a vacuum pump having an air intake port or an air exhaust port, and is characterized in that it comprises a shaft, a rotating wing, and a fracture portion limiting mechanism, wherein the shaft is rotatably supported on the fixed portion, the rotating wing has a plurality of sheets arranged in a multi-layered manner on the outer periphery to form a cylindrical shape, and is fixed to the shaft so as to be rotatable as a whole, and the fracture portion limiting mechanism is provided on the rotating wing to locally reduce the rigidity of the rotating wing and limit the fracture portion of the rotating wing.

[0028] According to this structure, when a torque exceeding the assumed value is generated and applied to the rotor, the part of the fracture part limiting mechanism provided on the rotor's rotating blade is fractured into a predetermined shape, etc., to absorb the impact of the torque. That is, the predetermined part of the rotor is fractured in a predetermined state, so that the post-fracture treatment can be simply performed in a predetermined process. As a result, the maintenance work can be stabilized and the treatment can be performed at a low cost.

[0029] The invention described in technical solution 7 provides a rotating wing, which is rotatably mounted via an axis on a fixing portion provided on the inner side of a shell of a vacuum pump having an air intake port or an air exhaust port, and is characterized in that it comprises a cylindrical component and a fracture portion limiting mechanism, wherein a plurality of sheets are provided in a multi-layered manner on the outer periphery of the cylindrical component to form a cylindrical shape, and the fracture portion limiting mechanism is provided on the cylindrical component to locally reduce the rigidity of the cylindrical component and limit the fracture portion of the cylindrical component.

[0030] According to this structure, when a torque exceeding the assumed value is generated and applied to the rotor, the part of the fracture part limiting mechanism provided in the cylindrical member is fractured into a predetermined shape, etc., to absorb the impact caused by the torque. That is, the predetermined part of the cylindrical member is fractured in a predetermined state, so that the post-fracture treatment can be simply performed according to a predetermined process. As a result, the maintenance work can be stabilized and the treatment can be performed at a low cost.

[0031] Effects of the Invention

[0032] According to the present invention, when a torque exceeding the assumed value is generated and applied to the rotor, the portion of the fracture portion limiting mechanism provided on the rotor's rotating blades is fractured into a predetermined shape, etc., and the impact caused by the torque can be absorbed. That is, a predetermined portion of the vacuum pump is fractured in a predetermined state, so the following effects are expected: post-fracture processing can be simply performed in a predetermined process, maintenance work can be stabilized, and processing can be performed at a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a top view of a vacuum pump shown as one embodiment of the present invention.

[0034] Figure 2 It is along Figure 1 Longitudinal section side view along line AA.

[0035] Figure 3 is used for Figure 1 and Figure 2 A top view of the rotary blades of a vacuum pump is shown.

[0036] Figure 4 It is along Figure 3 Longitudinal section side view of line BB.

[0037] Figure 5 This is a cross-sectional view illustrating an example of a groove as a fracture portion limiting mechanism of the vacuum pump described above.

[0038] Figure 6 This is a cross-sectional view illustrating a modified example of the groove as a fracture site limiting mechanism of the above vacuum pump.

[0039] Figure 7This is a cross-sectional view illustrating another modified example of the groove as a fracture portion limiting mechanism of the vacuum pump described above.

[0040] Figure 8 It is a top view of a vacuum pump shown as another embodiment of the present invention.

[0041] Fig. 9 It is along Figure 8 Longitudinal section side view of the CC line.

[0042] Fig.10 is used for Figure 8 and Fig. 9 A top view of the rotary blades of a vacuum pump is shown.

[0043] Fig.11 It is along Fig.10 Longitudinal section side view of DD line. DETAILED DESCRIPTION

[0044] The present invention is constructed as described below in order to achieve the following purpose. The above-mentioned purpose is to provide a vacuum pump and a rotor and a rotary wing for a vacuum pump, which have a structure in which a predetermined portion breaks in a predetermined state when a torque exceeding the assumed torque for rotating the rotor in the rotation direction of the rotor is instantaneously generated, thereby exerting a cheap and stable impact absorption performance. The above-mentioned vacuum pump comprises a shell, a fixing portion, and a rotor. The above-mentioned shell is formed with an air intake port or an air exhaust port. The above-mentioned fixing portion is arranged on the inner side of the above-mentioned shell. The above-mentioned rotor is built into the above-mentioned shell. The above-mentioned rotor has a shaft and a rotary wing. The above-mentioned shaft is rotatably supported by the above-mentioned fixing portion. The above-mentioned rotary wing is provided with a plurality of sheets in a multi-layered manner on the outer periphery to form a cylindrical shape, and is fixed to the above-mentioned shaft so as to be rotatable as a whole. It is characterized in that a fracture portion limiting mechanism is provided on the above-mentioned rotary wing. The above-mentioned fracture portion limiting mechanism locally reduces the rigidity of the above-mentioned rotary wing and limits the fracture portion of the above-mentioned rotary wing, thereby achieving the above-mentioned purpose.

[0045] Example

[0046] In the following, an embodiment of the present invention is described in detail based on the accompanying drawings. In addition, in the following embodiments, when the number, value, amount, range, etc. of the constituent elements are mentioned, except for the cases that are specifically indicated and the cases that are obviously limited to a specific number in principle, they are not limited to the specific number and can be more than or less than the specific number.

[0047] Furthermore, when referring to the shapes and positional relationships of components, the shapes and positional relationships of components that are substantially similar or similar to the shapes and positional relationships are included, except for cases where it is particularly noted or cases where it is obvious that this is not the case in principle.

[0048] In addition, the drawings may be exaggerated such as enlarging a feature portion to make the feature easier to understand, and the size ratio of the components is not necessarily the same as the actual one. In addition, in the cross-sectional view, the section lines of some components may be omitted to make the cross-sectional structure of the components easier to understand.

[0049] In addition, in the following description, the expressions indicating the directions such as up and down, left and right are not absolute, and should be interpreted as being suitable for describing the posture of each part of the wafer grinding device of the present invention, but when the posture changes, it changes accordingly. In addition, the same reference numerals are marked on the same elements throughout the entire description of the embodiments.

[0050] Figure 1 and Figure 2 An embodiment of the vacuum pump 10 of the present invention is shown. Figure 1 This is its top view. Figure 2 It is along Figure 1 Longitudinal section side view along line AA.

[0051] Figure 1 and Figure 2 The vacuum pump 10 shown is a compound pump having a molecular pump mechanism 10A and a threaded groove pump mechanism 10B as a gas exhaust mechanism. The vacuum pump 10 is used as a gas exhaust mechanism in a process chamber of a semiconductor manufacturing device, a flat panel display manufacturing device, a solar panel manufacturing device, or other closed chambers.

[0052] like Figure 1 As shown, the vacuum pump 10 includes a housing 11. Figure 2 As shown, the housing 11 is formed into a bottomed substantially cylindrical shape by integrally connecting a cylindrical pump cover 11A and a pump base 11B in the cylindrical axial direction thereof via a fastening member 12 .

[0053] The upper end side of the pump cover 11A ( Figure 2 As the air inlet 13 opening, in addition, Figure 2 As shown, an exhaust port 14 is provided at the pump base 11B. In addition, a flange 15 is formed at the air intake port 13, and a flange 16 is formed at the exhaust port 14. At the flange 15 of the air intake port 13, for example, a closed chamber (not shown) in a high vacuum such as a process chamber of a semiconductor manufacturing device is connected, and at the flange 16 of the exhaust port 14, an auxiliary pump (not shown) is connected.

[0054] Furthermore, a structure that performs exhaust function is housed inside the shell 11, and the gas in the sealed chamber is sucked from the air inlet 13 and discharged from the exhaust port 14. Thus, for example, reaction gas used in semiconductor manufacturing and other gases can be discharged from the sealed chamber. Figure 1 and Figure 2In the figure, the vacuum pump 10 is arranged vertically, but the vacuum pump 10 can also be installed horizontally on the lateral side of the closed chamber, or installed on the upper part of the closed chamber with the air intake port 13 at the lower side.

[0055] Furthermore, if described in detail, the structure that performs the exhaust function is roughly divided into a rotor 17 that is rotatably supported and a stator 18 that is fixed to the housing 11.

[0056] The rotor 17 is composed of rotor blades 19, a shaft 20, and the like.

[0057] Rotary Wing 19 Figure 1 and Figure 2 In addition Figure 3 and Figure 4 As shown, the cylindrical member 21 includes a first cylindrical portion 21a disposed on the air inlet 13 side (molecular pump mechanism 10A) and a second cylindrical portion 21b disposed on the air outlet 14 side (thread groove type pump mechanism 10B) formed integrally.

[0058] The first cylindrical portion 21a is a substantially cylindrical member and constitutes the rotor portion 17a of the molecular pump mechanism 10A. Figure 1 and Figure 3 , Figure 4 As shown in the figure, a plurality of sheets 22 extending radially outward from a surface perpendicular to the axis of the rotary blade 19 and the shaft 20 are arranged at approximately equal intervals in the direction of rotation. In addition, each sheet 22 is inclined in the same direction at a predetermined angle relative to the horizontal direction. And, in the first cylindrical portion 21a, these plurality of sheets 22 extending radially are formed in multiple layers at predetermined intervals in the axial direction.

[0059] In addition, if Figure 2 , Figure 4 As shown, a partition wall 23 for coupling with the shaft 20 is formed in the axial middle of the first cylindrical portion 21a. The partition wall 23 is formed with an axial hole 23a for inserting and installing the upper end side of the shaft 20, and a bolt hole 23b for installing a mounting bolt 24 for fixing the shaft 20. Eight bolt holes 23b are provided at equal intervals in the circumferential direction on concentric circles drawn with the axial hole 23a as the center. The number of bolt holes 23b is not limited to this.

[0060] The second cylindrical portion 21 b is a member having a cylindrical outer peripheral surface, and constitutes the rotor portion 17 b of the thread groove type pump mechanism 10B.

[0061] The shaft 20 is a cylindrical member constituting the shaft of the rotor 17. Figure 2As shown, at its upper end, a flange portion 20a is integrally formed with the bulkhead 23 of the first cylindrical portion 21a by means of a mounting bolt 24. Therefore, eight mounting holes not shown in the figure are provided in the flange portion 20a corresponding to the bolt holes 23b of the bulkhead 23. And, after the flange portion 20a integrated with the shaft 20 is inserted into the shaft hole 23a from the inner side (lower side) of the first cylindrical portion 21a so as to abut against the lower surface of the bulkhead 23, the mounting bolt 24 is threadedly fixed to the mounting hole of the flange portion 20a from the upper surface side of the bulkhead 23 through the bolt hole 23b, thereby being fixed to the cylindrical member 21 and integrated.

[0062] A permanent magnet is fixed to the outer circumference of the shaft 20 in the axial middle, constituting the rotor 17 side of the motor unit 25. The magnetic poles formed by the permanent magnet on the outer circumference of the shaft 20 are N poles over half of the outer circumference and S poles over the remaining half.

[0063] Furthermore, a portion of the rotor 17 side of the magnetic bearing portion 26 for supporting the shaft 20 in the radial direction relative to the motor portion 25 is formed on the upper end side (the air inlet 13 side) of the shaft 20, and a portion of the rotor 17 side of the magnetic bearing portion 27 for supporting the shaft 20 in the radial direction relative to the motor portion 25 is similarly formed on the lower end side (the exhaust port 14 side). In addition, at the lower end of the shaft 20, a portion of the rotor 17 side of the magnetic bearing portion 28 for supporting the shaft 20 in the axial direction (thrust direction) is formed.

[0064] Furthermore, portions of the displacement sensors 29 and 30 on the rotor 17 side are formed near the magnetic bearings 26 and 27 , respectively, so that displacement of the shaft 20 in the radial direction can be detected.

[0065] Furthermore, a portion of the displacement sensor 31 on the rotor 17 side is formed at the lower end of the shaft 20 , so that the axial displacement of the shaft 20 can be detected.

[0066] The rotor 17 side portions of the magnetic bearings 26, 27 and the displacement sensors 29, 30 are formed of laminated steel plates formed by laminating steel plates in the axial direction of the rotor 17. This is to prevent eddy currents from being generated in the shaft 20 due to the magnetic field generated by the windings of the magnetic bearings 26, 27 and the stator 18 side portions of the displacement sensors 29, 30.

[0067] The rotor 17 described above is made of metal such as stainless steel or aluminum alloy.

[0068] Furthermore, a fractured portion restricting groove 32 serving as a fractured portion restricting mechanism is provided in the first cylindrical portion 21 a of the rotary blade 19 of the rotor 17 .

[0069] The fracture position limiting groove 32 is as follows Figure 1 to Figure 4As shown in FIG. 1 , the first fracture site limiting groove 32a is formed along the axial direction on the outer peripheral surface of the first cylindrical portion 21a. Figure 2 and Figure 4 As shown, the second fracture portion limiting groove 32b is formed along the outer circumference of the lower end of the first cylindrical portion 21a adjacent to the second cylindrical portion 21b.

[0070] The first fracture site limiting grooves 32a are arranged on the outer circumferential surface of the first cylindrical portion 21a, between the adjacent pieces 22 in the axial direction, at substantially equal intervals in the circumferential direction and along the axial direction of the rotary blade 19. The first fracture site limiting grooves 32a also depend on the material and thickness of the cylindrical member 21, but for example, the width is 5.8 mm, the depth is 8 to 15 mm, and the cross-sectional shape is as follows: Figure 5 The shape of the concave curved surface is shown as a semicircular shape. The portion of the first cylindrical portion 21a of the rotary wing 19 provided with the first fracture portion limiting groove 32a of the first cylindrical portion 21a is thinner than other portions not provided with the first fracture portion limiting groove 32a, and the mechanical strength is reduced. Therefore, when a torque exceeding the assumed value is generated and applied to the rotor 17, the portion of the portion of the first cylindrical portion 21a of the rotary wing 19 provided with the first fracture portion limiting groove 32a formed in the axial direction on the outer peripheral surface thereof is fractured in a predetermined state in the axial direction, and the impact of the vacuum pump 10 as a whole caused by the torque can be absorbed by the fracture.

[0071] The second fracture site limiting groove 32b is horizontally formed along the outer circumference of the lower end of the first cylindrical part 21a adjacent to the second cylindrical part 21b to form a substantially circular shape. The second fracture site limiting groove 32b is also determined by the material and thickness of the cylindrical part 21, as is the case with the first fracture site limiting groove 32a, but for example, the width is 5.8 mm, the depth is 8 to 15 mm, and the cross-sectional shape is a semicircular concave curved surface shape, as is the first fracture site limiting groove 32a. The second fracture site limiting groove 32b is provided adjacent to the second cylindrical part 21b on the outer circumference of the lower end of the first cylindrical part 21a, and thus, the part of the cylindrical part 21 of the rotary wing 19 provided with the second fracture site limiting groove 32b is thinner than other parts without the groove, as is the case with the first fracture site limiting groove 32a, and the mechanical strength is reduced. Thus, when a torque exceeding the assumed value is generated and the torque is applied to the rotor 17, the portion of the cylindrical member 21 provided with the second fracture portion limiting groove 32b formed along the outer circumference of the lower end of the first cylindrical portion 21a adjacent to the second cylindrical portion 21b is substantially fractured at the portion of the boundary line between the first cylindrical portion 21a and the second cylindrical portion 21b ( Figure 4 The portion indicated by a dashed line and marked with reference numeral 33 is hereinafter referred to as "boundary line 33". ) That is, a predetermined portion is broken and separated into the first cylindrical portion 21a and the second cylindrical portion 21b, and the impact caused by the torque can be absorbed by the breakage.

[0072] The stator 18 is formed on the inner circumference of the housing 11. The stator 18 is composed of a stator piece 34 provided on the air inlet 13 side (molecular pump mechanism 10A), a thread groove spacer 35 provided on the air outlet 14 side (thread groove pump mechanism 10B), and the like.

[0073] The stator pieces 34 are formed of pieces extending from the inner circumference of the shell 11 toward the shaft 20 at a predetermined angle from a plane perpendicular to the axis of the shaft 20, and in the molecular pump mechanism 10A, these stator pieces 34 are formed in multiple layers in the axial direction alternately with the pieces 22 of the rotary blades 19. The stator pieces 34 of each layer are separated from each other by spacers 36 having a cylindrical shape.

[0074] The spiral groove spacer 35 is a cylindrical member having a spiral groove 35a formed on the inner circumferential surface. The inner circumferential surface of the spiral groove spacer 35 faces the outer circumferential surface of the second cylindrical portion 21b of the cylindrical member 21 with a predetermined gap (clearance) therebetween. The direction of the spiral groove 35a formed in the spiral groove spacer 35 is the direction toward the exhaust port 14 when the gas is transported in the spiral groove 35a along the rotation direction of the rotor 17. The depth of the spiral groove 35a becomes shallower as it approaches the exhaust port 14, and the gas transported in the spiral groove 35a is compressed as it approaches the exhaust port 14.

[0075] The stators 18 are made of metal such as stainless steel or aluminum alloy.

[0076] The pump base 11B is a disc-shaped member, and a cylindrical stator column 37 is installed in the radial center concentric with the rotation axis of the rotor 17 toward the air inlet 13. The stator column 37 supports the motor 25, the magnetic bearings 26, 27, and the stator side of the displacement sensors 29, 30.

[0077] In the motor part 25, stator windings with a predetermined number of poles are arranged at equal intervals on the inner circumference of the stator windings, and a rotating magnetic field can be generated around the magnetic poles formed on the shaft 20. In addition, a sleeve 38 as a cylindrical member made of metal such as stainless steel is arranged on the outer circumference of the stator winding to protect the motor part 25.

[0078] The magnetic bearings 26 and 27 are composed of windings arranged every 90 degrees around the rotation axis, and the magnetic bearings 26 and 27 attract the shaft 20 by the magnetic field generated by the windings, so that the shaft 20 is magnetically levitated in the radial direction.

[0079] A magnetic bearing 28 is formed at the bottom of the stator column 37. The magnetic bearing 28 is composed of a disk extending from the shaft 20 and windings arranged above and below the disk. The magnetic field generated by the windings attracts the disk, thereby magnetically levitating the shaft 20 in the axial direction.

[0080] The flange 15 extending toward the outer peripheral side of the pump cover 11A is formed at the air inlet 13 of the shell 11. The flange 15 is provided with a bolt hole 39 for inserting a bolt not shown in the figure and a groove 40 for assembling an O-ring for maintaining airtightness with the flange on the vacuum container side not shown in the figure.

[0081] The vacuum pump 10 configured as described above operates as follows to exhaust gas from the vacuum container.

[0082] First, the magnetic bearings 26 , 27 , and 28 magnetically float the shaft 20 , thereby supporting the rotor 17 in a non-contact manner in space.

[0083] Next, the motor unit 25 is operated to rotate the rotor 17 in a predetermined direction. The rotation speed is, for example, about 30,000 revolutions per minute. Figure 2 Observe from the direction of arrow line E, Figure 1 The direction of the vacuum pump 10 is a clockwise rotation direction as shown by the arrow line R. In addition, the vacuum pump 10 can also be configured to rotate in the counterclockwise rotation direction.

[0084] When the rotor 17 rotates, the gas is sucked from the air inlet 13 by the action of the blades 22 of the rotor 19 and the stator blades 34 of the stator 18, and is compressed as it moves downward. The gas compressed at the molecular pump mechanism 10A is further compressed at the screw groove pump mechanism 10B and discharged from the exhaust port 14.

[0085] Next, in the vacuum pump 10 configured as described above, a process when a torque exceeding the assumed value is generated in the rotor 17 and the torque is applied to the rotor 17 will be described.

[0086] In the vacuum pump 10 of this embodiment, a plurality of first fracture site limiting grooves 32a and second fracture site limiting grooves 32b are provided on the outer peripheral surface of the first cylindrical portion 21a. The portion of the rotary wing 19 provided with these first fracture site limiting grooves 32a and second fracture site limiting grooves 32b is thinner than other portions not provided with the first fracture site limiting grooves 32a and second fracture site limiting grooves 32b, and the mechanical strength is reduced. Therefore, when the above torque is assumed to be generated and applied to the rotor 17, the first fracture site limiting grooves 32a and / or the second fracture site limiting grooves 32b are broken into a predetermined state along these grooves, so that the first cylindrical portion 21a and the second cylindrical portion 21b are separated into multiple pieces, and the impact caused by the torque is absorbed along the separation. Here, for example, cracks are generated in the first cylindrical portion 21a along the multiple first fracture site limiting grooves 32a, the first cylindrical portion 21a is broken in the axial direction and divided into multiple pieces, or / and the first cylindrical portion 21a and the second cylindrical portion 21b are broken along the axial direction. Figure 4The boundary line 33 shown is broken along the circumferential direction and divided into a plurality of parts. That is, the first breaking part limiting groove 32a and / or the second breaking part limiting groove 32b are broken at a predetermined position in a predetermined state, so that the post-breaking treatment can be simply performed in a determined process. Thus, the maintenance operation can be stabilized and the treatment can be performed at a low cost.

[0087] In addition, the first fracture site limiting groove 32a as the fracture site limiting mechanism is provided corresponding to the shaft 20 and the plurality of bolt holes 23b fixed by bolts. Therefore, the portion provided with the first fracture site limiting groove 32a and the portion provided with the bolt holes 23b are fragile and mechanical strength is reduced compared with other portions, so when a torque exceeding the assumed value is generated and the torque is applied to the rotor 17, the first fracture site limiting groove 32a and the portion connected to the first fracture site limiting groove 32a and the bolt holes 23b are also easily fractured in a predetermined state, and the fracture at this portion also absorbs the impact caused by the torque, so the post-fracture treatment can be simply performed in a determined process.

[0088] In addition, in the above-mentioned embodiment, the cross-sectional shapes of the first fracture site limiting groove 32a and the second fracture site limiting groove 32b are disclosed as follows: Figure 5 The structure shown is a semicircular concave curved surface, but is not limited to the semicircular concave curved surface. For example, it can also be as Figure 6 As shown in the shape of a four-sided concave surface, or as Figure 7 The shape shown is a V-shaped concave shape.

[0089] Figure 8 to Figure 11 A modified example of the vacuum pump 10 of the present invention is shown. Figure 8 This is its top view. Fig. 9 It is along Figure 8 The longitudinal section side view of the CC line, Fig.10 yes Figure 8 and Fig. 9 A top view of the rotary wing 19 used in the vacuum pump is shown, Fig.11 It is along Fig.10 Longitudinal section side view of DD line. Figure 8 to Figure 11 The variation shown is similar to Figure 1 to Figure 7 The first fracture site limiting grooves 32a of the vacuum pump 10 of the embodiment shown are arranged at substantially equal intervals on the outer circumferential surface of the first cylindrical portion 21a in the circumferential direction and arranged in the axial direction of the rotary blade 19, and are arranged at substantially equal intervals on the inner circumferential surface of the first cylindrical portion 21a in the circumferential direction and arranged in the axial direction of the rotary blade 19. Figure 1 to Figure 4 Therefore, the same components are denoted by the same reference numerals and repeated description is omitted.

[0090] Therefore, if the description Figure 1 to Figure 4The embodiment shown in the figure is different from the structure in that the first fracture portion limiting groove 132a of the fracture portion limiting groove 32 is formed in the axial direction on the inner peripheral surface of the first cylindrical portion 21a, and the second fracture portion limiting groove 32b of the fracture portion limiting groove 32 is formed in the axial direction on the inner peripheral surface of the first cylindrical portion 21a. Figure 1 to Figure 4 In the illustrated embodiment, the outer circumference of the lower end of the first cylindrical portion 21a adjacent to the second cylindrical portion 21b is similarly formed.

[0091] The first fracture site limiting groove 132a is as follows Figure 8 to Figure 11 As shown, on the inner circumferential surface of the first cylindrical part 21a, the first fracture part limiting groove 132a is dispersed at approximately equal intervals in the circumferential direction and is provided along the axial direction of the rotary wing 19. The first fracture part limiting groove 132a here also depends on the material and thickness of the cylindrical part 21, but for example, the width is 5.8 mm and the depth is 8 to 15 mm. The first fracture part limiting groove 132a is provided, and thus the part of the rotary wing 19 provided with the first fracture part limiting groove 132a is thinner than other parts without the groove, and the mechanical strength is reduced. In addition, the first fracture part limiting groove 132a is provided corresponding to the shaft 20 and the plurality of bolt holes 23b fixed by bolts. Therefore, it is set so that the part provided with the first fracture part limiting groove 32a and the part provided with the bolt hole 23b are fragile compared with other parts and the mechanical strength is reduced. Thus, when the rotor 17 generates a torque greater than the assumed value and the torque is applied to the rotor 17, the first fracture portion limiting groove 132a axially provided on the inner circumferential surface of the first cylindrical portion 21a serving as the rotating wing 19 fractures in a predetermined state along the axial direction, and the impact caused by the torque can be absorbed by the fracture.

[0092] Therefore, in Figure 8 to Figure 11In the modified example shown, a plurality of first fracture site limiting grooves 132a are also provided on the inner circumferential surface of the first cylindrical portion 21a at approximately equal intervals in the circumferential direction and along the axial direction of the rotary blade 19, and a second fracture site limiting groove 32b is provided on the outer circumference of the lower end of the first cylindrical portion 21a adjacent to the second cylindrical portion 21b, which surrounds the outer circumference of the first cylindrical portion 21a and forms approximately one circle horizontally. The portion of the rotary blade 19 provided with the first fracture site limiting grooves 132a and the second fracture site limiting grooves 32b is thinner than other portions not provided with the first fracture site limiting grooves 132a and the second fracture site limiting grooves 32b, and the mechanical strength is reduced. Therefore, when the above torque is generated and applied to the rotor 17, the portion of the first fracture site limiting groove 132a or / and the second fracture site limiting groove 32b is broken into a predetermined state along these grooves, so that the first cylindrical portion 21a and the second cylindrical portion 21b are separated into a plurality of portions, and the impact caused by the torque is absorbed as they separate. Here, for example, cracks are generated in the first cylindrical portion 21a along the plurality of first fracture site limiting grooves 132a, the first cylindrical portion 21a is fractured in the axial direction and divided into a plurality of parts, or / and cracks are generated along the first cylindrical portion 21a and the second cylindrical portion 21b. Figure 4 The boundary line 33 shown is broken along the circumferential direction and divided into a plurality of parts. That is, the first breaking part limiting groove 132a and / or the second breaking part limiting groove 32b are broken at a predetermined position in a predetermined state, so that the post-breaking treatment can be simply performed in a determined process. Thus, the maintenance operation can be stabilized and the treatment can be performed at a low cost.

[0093] In addition, in the vacuum pump 10 of this modified example, a structure is disclosed in which the second rupture portion limiting groove 32b is formed horizontally and approximately in one circle around the outer circumference of the first cylindrical portion 21a, but it may also be a structure formed horizontally and approximately in one circle on the inner circumference side of the first cylindrical portion 21a.

[0094] In addition, the first fracture part limiting groove 132a as the fracture part limiting mechanism is provided corresponding to the shaft 20 and the plurality of bolt holes 23b fixed by bolts, so the portion provided with the first fracture part limiting groove 132a and the portion provided with the bolt holes 23b are fragile compared with other portions and the mechanical strength is reduced. Therefore, when the rotor 17 generates a torque exceeding the assumed torque and the torque is applied to the rotor 17, the first fracture part limiting groove 32a and the portion connected to the first fracture part limiting groove 132a and the bolt holes 23b are fractured in a predetermined state, absorbing the impact caused by the torque, so that the post-fracture treatment can be simply performed in a predetermined process.

[0095] In addition, in this modified example, the cross-sectional shape of the first fracture site limiting groove 132a and the second fracture site limiting groove 32b is disclosed to be formed into a semicircular surface shape, but is not limited to the semicircular surface shape, for example, it can also be a quadrilateral shape, or a V-shaped surface shape, etc.

[0096] In addition, the present invention can be modified in various ways without departing from the spirit of the present invention, and the present invention obviously also covers such modifications.

[0097] Description of Reference Numerals

[0098] 10: Vacuum pump

[0099] 10A: Molecular pump mechanism

[0100] 10B: Threaded groove pump mechanism

[0101] 11: Shell

[0102] 11A: Pump cover

[0103] 11B: Pump base

[0104] 12: Fasten the connecting parts

[0105] 13: Intake port

[0106] 14: Exhaust port

[0107] 15: Flange

[0108] 16: Flange

[0109] 17: Rotor

[0110] 17a: Rotor

[0111] 17b: Rotor

[0112] 18: Stator

[0113] 19: Rotary Wing

[0114] 20: Axis

[0115] 20a: convex edge

[0116] 21: Cylindrical parts

[0117] 21a: First cylindrical part

[0118] 21b: Second cylindrical part

[0119] 22: Piece

[0120] 23: Next Door

[0121] 23a: Shaft hole

[0122] 23b: Bolt hole

[0123] 24: Mounting bolts

[0124] 25: Motor

[0125] 26: Magnetic bearing

[0126] 27: Magnetic bearing

[0127] 28: Magnetic bearing

[0128] 29: Displacement sensor

[0129] 30: Displacement sensor

[0130] 31: Displacement sensor

[0131] 32: Fracture limit groove

[0132] 32a: 1st fracture site limiting groove

[0133] 32b: Second fracture site limiting groove

[0134] 33: Borderline

[0135] 34: Stator segment

[0136] 35: Thread groove spacer

[0137] 35a: Spiral groove

[0138] 36: Spacer

[0139] 37: Stator column

[0140] 38: Casing

[0141] 39: Bolt hole

[0142] 40: Slot

[0143] 132a: 1st fracture site limiting groove

[0144] E: Arrow line

[0145] R: Arrow line.

Claims

1. A vacuum pump comprising a shell, a fixing portion, and a rotor, wherein the shell is formed with an air intake port or an air exhaust port, the fixing portion is arranged inside the shell, the rotor is built into the shell, the rotor has a shaft and a rotary wing, the shaft is rotatably supported by the fixing portion, the rotary wing is provided with a plurality of sheets in a multi-layered manner on the outer periphery, is formed into a cylindrical shape, and is fixed to the shaft so as to be rotatable as a whole, characterized in that: The rotor blade is provided with a fractured portion limiting mechanism, wherein the fractured portion limiting mechanism partially reduces the rigidity of the rotor blade to limit the fractured portion of the rotor blade. The fracture portion limiting means is a groove having a length, a width shorter than the length, and a depth, provided on the outer peripheral surface of the rotary wing in a manner extending along the axial direction of the rotary wing with the length between the axially adjacent pieces, or a groove provided on the inner peripheral surface of the rotary wing in a manner extending along the axial direction of the rotary wing with the length, The grooves are provided at intervals in the circumferential direction of the rotor blade.

2. The vacuum pump according to claim 1, characterized in that The fractured portion limiting mechanism further includes a groove provided along the circumferential direction of the rotor blade on at least one of the outer peripheral surface or the inner peripheral surface of the rotor blade.

3. The vacuum pump according to claim 1, characterized in that The circumferential position of the groove is provided to correspond to the circumferential position of a plurality of bolt holes provided in the rotor blade for mounting the rotor blade on the shaft.

4. A rotor rotatably mounted on a fixing portion provided inside a housing of a vacuum pump having an air intake port or an air exhaust port, characterized in that: Equipped with shaft, rotating wings, and fracture limit mechanism, The shaft is rotatably supported by the fixing portion. The rotor blade is provided with a plurality of sheets in a multi-layered manner on the outer periphery thereof, formed into a cylindrical shape, and fixed to the shaft so as to be rotatable as a whole. The fractured portion limiting mechanism is provided on the rotor blade, and partially reduces the rigidity of the rotor blade to limit the fractured portion of the rotor blade. The fracture portion limiting means is a groove having a length, a width shorter than the length, and a depth, provided on the outer peripheral surface of the rotary wing in a manner extending along the axial direction of the rotary wing by the length between the axially adjacent pieces, or a groove provided on the inner peripheral surface of the rotary wing in a manner extending along the axial direction of the rotary wing by the length, The grooves are provided at intervals in the circumferential direction of the rotor blade.

5. A rotary blade rotatably mounted via a shaft to a fixing portion provided inside a housing of a vacuum pump having an air intake port or an air exhaust port, characterized in that: Equipped with cylindrical parts and fracture limit mechanism, The cylindrical member is provided with a plurality of sheets in a multi-layered manner on the outer periphery to form a cylindrical shape. The fracture site limiting mechanism is provided on the cylindrical member, so that the rigidity of the cylindrical member is partially reduced, thereby limiting the fracture site of the cylindrical member. The fracture portion limiting means is a groove having a length, a width shorter than the length, and a depth, provided on the outer peripheral surface of the cylindrical member in a manner extending along the axial direction of the rotary blade by the length between the axially adjacent pieces, or a groove provided on the inner peripheral surface of the cylindrical member in a manner extending along the axial direction of the rotary blade by the length, The grooves are provided at intervals in the circumferential direction of the cylindrical member.

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