JP2006090231A - Method for manufacturing fixed blade of turbo molecular pump and vacuum pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing turbo molecular pump fixed blades suitable for improving strength of the turbo molecular pump fixed blades. <P>SOLUTION: Slits 102 and small holes 103, 104 are formed on a half ring shaped plate material 100, and the fixed blades 14 are cut and raised from the half ring shaped plate material 100 on which the slits 102 and small holes 103, 104 are formed. At this time, the plurality of slits 100 are radially formed on the half ring shaped plate material 100 at regular intervals. As for cutting and raising of the fixed blades 14, first and second cuts 105, 106 are formed between the slits 102, 102 adjacent to each other. At the same time, spaces between terminals 105a, 106a of the both cuts 105, 106 are used as bent lines and plate material portions 107 between the both slits 102, 102 are bent so as to be raised in the cut direction by press. The small holes 103, 104 are preset in portions serving as the terminals 105a, 106a of the both cuts 105, 106 at the time of cutting and raising the fixed blades 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a turbomolecular pump fixed blade, and in particular, can improve the strength of the turbomolecular pump fixed blade.

  This type of turbomolecular pump fixed blade is disposed in the turbomolecular pump in a ring shape by abutting two semi-ring shaped fixed blade assemblies 72 shown in FIG. Each fixed blade assembly 72 has a structure in which a plurality of fixed blades 75, 75... Arranged in a radial manner are integrally connected by a pair of inner and outer rim portions 73 and 74 (for example, Patent Document 1). FIG. 2 (a)).

  As described above, the plurality of fixed blades 14, 14... Connected by the pair of inner and outer rim portions 73, 74 are cut and raised at a time by a press. That is, when manufacturing the fixed wings 75, 75..., First, a plurality of radial slits are formed in the semi-ring plate, and then a plate portion between the two adjacent slits is used as a fixed wing 75 with a press. It is supposed to cut.

  However, according to the method of cutting the fixed wing 75 as described above, the cuts that enter both sides of the fixed wing 75 become longer than necessary during the cutting and raising, and the width L4 of the base portion of the fixed wing 75 (FIG. 6). May be narrower than the set value. For this reason, the strength of the fixed wing 75 is insufficient, and there is a possibility that the fixed wing 75 bends due to the atmospheric flow when entering the atmosphere or the gas flow during normal operation and comes into contact with the rotary blade 13 (see FIG. 1). There is a problem.

Patent No. 3013083

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for manufacturing a turbomolecular pump fixed blade suitable for improving the strength of the turbomolecular pump fixed blade, and a vacuum pump. It is to provide.

  In order to achieve the above object, the present invention provides a method of manufacturing a turbomolecular pump fixed blade having a structure in which a plurality of fixed blades arranged in a radial pattern are integrally connected by a pair of inner and outer rim portions. The method of manufacturing a turbomolecular pump fixed blade includes a step of forming a slit and a small hole in a half ring-shaped plate member, and a step of cutting the fixed blade from the half ring-shaped plate member formed with the slit and the small hole. Are formed radially at regular intervals on the semi-ring plate, and the fixed blade is cut and raised by inserting first and second cuts between two adjacent slits of the plurality of slits. At the same time, the plate material portion between the slits is bent so as to be raised by the press in the incision direction with the end line between the first and second incisions as a fold line, and the small hole is formed on the fixed wing. Ri and wherein the advance be provided at a position that terminates the first and second cuts during raised.

  The present invention provides a vacuum pump comprising a stationary blade rotating integrally with a rotor around a pump axis and a turbomolecular pump rotating blade fixed at a fixed position alternately in multiple stages. The molecular pump fixed wing includes a plurality of fixed wings that are cut and raised so as to be arranged in a radial pattern, and the end of each notch that enters both sides of each fixed wing by the raised wing of the fixed wing. The structure is characterized by having a small hole in the part.

  In the present invention, as described above, a configuration is adopted in which a small hole is provided in advance at a location that is the end of the first and second cuts when the fixed wing is cut and raised. For this reason, there is a small hole opened in advance at the point where the first and second incisions advance and arrive when the fixed wing is raised, that is, at the end of the incision, and the first and second incisions are formed by the small holes. Therefore, the width of the base portion of the fixed wing, that is, the width from the end of the notch to the slit at the tip is constant. For this reason, the width of the root portion of the fixed wing becomes narrower than the set value, that is, it is possible to prevent a decrease in strength of the fixed wing due to entering the cut longer than necessary. It is possible to prevent contact between the fixed blade and the rotor blade due to the atmospheric flow when entering the atmosphere and the gas flow during normal operation.

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

  The vacuum pump P shown in FIG. 1 is used as a part of a vacuum device in a semiconductor manufacturing apparatus or a liquid crystal display panel manufacturing apparatus, and makes the pressure in the vacuum chamber a predetermined degree of vacuum. Moreover, the vacuum pump P of the figure is a composite pump having a part functioning as the turbo molecular pump Pt and a part functioning as the screw pump Ps in the exterior case 1.

  The outer case 1 has a bottomed cylindrical case structure in which a cylindrical pump case 1-1 and a bottomed cylindrical pump base 1-2 are integrally connected with bolts in the direction of the cylinder axis. Moreover, the upper end part side of the pump case 1-1 opens as the gas inlet port 2, and the gas exhaust port 3 is opened in the lower end side surface of the pump base 1-2.

  The gas inlet 2 is connected to a vacuum container (not shown) side that is high vacuum, such as a process chamber of a semiconductor manufacturing apparatus, via a bolt (not shown) provided on the flange at the upper edge of the pump case 1-1. . Further, the gas exhaust port 3 is connected to communicate with an auxiliary pump (not shown).

  A cylindrical stator column 4 that houses various electrical components is provided in the center of the pump case 1-1. The lower end side of the stator column 4 is screwed and fixed on the pump base 1-2 and is erected on the pump base 1-2.

  A rotor shaft 5 is provided inside the stator column 4. The rotor shaft 5 is arranged such that the upper end of the shaft faces the direction of the gas intake port 2 and the lower end of the shaft faces the direction of the pump base 1-2. The upper end of the rotor shaft 5 is formed so as to protrude from the cylindrical upper end surface of the stator column 4.

  A rotor 6 is provided outside the stator column 4. The rotor 6 is housed in the pump case 1-1 and is formed in a cylindrical shape that surrounds the outer periphery of the stator column 4. The rotor 6 is integrally attached and fixed to the upper end side of the rotor shaft 5. Various structures for attaching and fixing the rotor 6 to the rotor shaft 5 are conceivable. In the vacuum pump P of FIG. 1, as an example of the structure, a flange 8 with a boss hole 7 is integrally provided inside the upper end of the rotor 6, and a step 9 is formed on the outer periphery of the upper end of the rotor shaft 5. A structure is adopted in which the tip end portion of the rotor shaft 5 above the portion 9 is fitted into the boss hole 7 of the flange 8 and the flange 8 and the stepped portion 9 are fixed with screws. Therefore, when the rotor shaft 5 rotates, the rotor 6 also rotates integrally with the rotor shaft 5.

  The rotating body composed of the rotor shaft 5 and the rotor 6 as described above is supported by the radial magnetic bearing 10 and the axial magnetic bearing 11 so as to be rotatable in the axial direction and the radial direction. In this state, the drive motor 12 is centered on the rotor shaft 5. It is rotationally driven by.

  The drive motor 12 has a structure including a stator 12-1 and a rotor 12-2, and is provided near the center of the rotor shaft 5. The stator 12-1 of the drive motor 12 is installed on the side surface of the stator column 4 circle, and the rotor 12-2 of the drive motor 12 is integrally mounted on the outer peripheral surface side of the rotor shaft 5.

  Two sets of radial magnetic bearings 10 are arranged one by one above and below the drive motor 12, and one set of axial magnetic bearings 11 is arranged on the lower end side of the rotor shaft 5.

  The two sets of radial magnetic bearings 10, 10 are respectively a radial electromagnet target 10-1 attached to the outer peripheral surface of the rotor shaft 5 and a plurality of radial electromagnets 10-installed on the inner side surface of the stator column 4 facing this. 2 and a radial displacement sensor 10-3.

  The radial electromagnet target 10-1 is made of a laminated steel plate in which steel plates of high permeability material are laminated, and the radial electromagnet 10-2 attracts the rotor shaft 5 with a magnetic force in the radial direction via the radial electromagnet target 10-1. The radial direction displacement sensor 10-3 is configured to detect the radial displacement of the rotor shaft 5.

  And in the radial magnetic bearings 10 and 10 of the said structure, the exciting current of the radial electromagnet 10-2 is controlled based on the detection value (radial direction displacement of a rotor shaft) by the radial direction displacement sensor 10-3. The entire rotating body including the shaft 5 and the rotor 6 is levitated and supported at a predetermined position in the radial direction.

  The axial magnetic bearing 11 includes a disk-shaped armature disk 11-1 attached to the outer periphery of the lower end portion of the rotor shaft 5, and an axial electromagnet 11-2 disposed at a vertical position facing the armature disk 11-1. And an axial direction displacement sensor (not shown) installed at a position slightly away from the lower end surface of the rotor shaft 5.

  The armature disk 11-1 is made of a material having high magnetic permeability, and the upper and lower axial electromagnets 11-2 are configured to attract the armature disk 11-1 from the upper and lower directions by a magnetic force, and the axial direction displacement sensor is a rotor shaft. 5 is configured to detect an axial displacement.

  In the axial magnetic bearing 11 having the above structure, the excitation current of the upper and lower axial electromagnets 11-2 is controlled based on the value detected by the axial displacement sensor (axial displacement of the rotor shaft). A rotating body composed of the rotor 6 is levitated and supported at a predetermined position in the axial direction.

  In the vacuum pump shown in FIG. 1, the upper half of the rotor 6 functions as a turbo molecular pump Pt. Hereinafter, the site | part which functions as this turbo-molecular pump Pt is demonstrated.

  A plurality of rotor blades 13 are integrally provided on the upper outer peripheral surface of the rotor 6, and these rotor blades 13 serve as the rotation center of the rotor 6 or the axis of the outer case 1 (hereinafter referred to as “pump axis”). They are arranged radially as the center. On the other hand, a plurality of fixed wings 14 are provided on the inner peripheral surface side of the pump case 1-1, and these fixed wings 14 are arranged side by side radially about the pump shaft center, like the rotary blades 13. Yes. Further, such rotary blades 13 and fixed blades 14 are alternately arranged in multiple stages along the pump axis.

  Each of the rotor blades 13 is a blade-like cut product that is cut and formed integrally with the outer diameter machining portion of the rotor 2 and is inclined at an optimum angle for exhausting gas molecules. Further, as shown in FIG. 5, each of the fixed blades 14 is inclined at an optimum angle for exhausting gas molecules.

  In the case of the vacuum pump of FIG. 1, the portion of the blade structure composed of the plurality of rotor blades 13 and fixed blades 14 arranged as described above functions as a turbo molecular pump by the rotation of the rotor 6. That is, when the drive motor 12 is operated, the rotor shaft 5, the rotor 6, and the rotary blades 13 are integrally rotated at a high speed. The uppermost rotating blade 13 rotating at a high speed imparts a downward momentum to the gas molecules incident from the gas inlet 2, and the gas molecules having the downward momentum are moved by the fixed blade 14 to the next rotating blade 13. It is sent to the side. By applying the momentum to the gas molecules and performing the feeding operation repeatedly in multiple stages, the gas molecules on the gas inlet 2 side are sequentially transferred to the upstream side of the screw pump Ps and exhausted.

  Next, the manufacturing method of the fixed wing | blade 14 is demonstrated. In the present embodiment, the fixed wings 14 of each stage shown in FIG. 1 are manufactured together with other fixed wings 14 of the same stage in the form of an integrated product called a fixed wing assembly 14n shown in FIG. It arrange | positions at the internal peripheral surface side of case 1-1.

  Note that the fixed blade assembly 14n shown in FIG. 4 has a half ring shape as a whole, and the vacuum pump 1 is formed by abutting two such half ring shape fixed blade assemblies 14n into a ring shape. It is a turbo-molecular pump fixed blade | wing arrange | positioned in the inside.

  Here, the fixed wing assembly 14n in FIG. 4 will be briefly described. The fixed wing assembly 14n in FIG. 4 has a plurality of fixed wings 14, 14,. A plurality of fixed wings are structured to be integrally connected to each other by a pair of inner and outer rim portions 15 and 16 having a semicircular arc shape, and the outer end portion 14a of each fixed wing 14 is connected to the outer rim portion 15. The inner end of each fixed wing 14 is connected to the inner rim 16. Since the fixed blade assembly 14n has a structure in which the fixed blades 14 having the same shape are repeatedly arranged, only about 1/3 of the fixed blade assembly 14n is shown in FIG. 4, and about 2/3 thereof is omitted. .

  FIGS. 2 and 3 are explanatory views of a process of manufacturing a part of the turbomolecular pump fixed blade, that is, the fixed blade assembly 4n of FIG. 4, and these steps will be described below in order.

  In step 1 of FIG. 2, as shown by the dotted line in the figure, the semi-ring-shaped plate material 101 is punched from the plate material 100 (outline punching process). A punching press process can be applied to the outer shape punching process.

  In step 2 of FIG. 3, as shown in the figure, slits 102 and small holes 103 and 104 are formed in the semi-ring plate 101 produced in step 1 (slit and hole forming process). Punching press processing can also be applied to the slit and small hole forming processing.

  Here, a plurality of the slits 102 are radially formed in the semi-ring-shaped plate material 101 at regular intervals. The small holes 103 and 104 are provided in advance at locations where the first and second cut ends 105a and 106a (see FIG. 6) are formed when the fixed blade 14 described later is cut and raised. Further, when the fixed blade 14 described later is cut and raised, the above two cuts, specifically, a first cut 105 from one end 102a of one slit 102 toward one end 102a of the adjacent slit 102, Since the second cut 106 is made from the other end 102b of the slit 102 toward the other end 102b of the adjacent slit 102 (see FIG. 4 and FIG. 6), the outer side provided at the location serving as the end 105a of the first cut. The small hole 103 is formed on a line segment (dotted line L1 in FIG. 3) connecting the ends 102a, 102a of two adjacent slits 102-1, 102-2. On the other hand, the inner small hole 104 provided at the position serving as the terminal end 106a of the second cut is on a line segment (the dotted line L2 in FIG. 3) connecting the other ends 102b, 102b of the two adjacent slits 102, 102. Formed. The inner and outer small holes 103 and 104 may have the same diameter. For example, the outer small hole 103 may have a large diameter, and the inner small hole 104 may have a small diameter.

  When the slit and small hole forming process as described above is completed, the fixed wing 14 is then cut out from the half ring-shaped plate material 101 in which the slit 102 and the small holes 103 and 104 are formed. The fixed wing 14 is cut and raised while the first and second cuts are made simultaneously while two cuts 105 and 106 are inserted between two adjacent slits 102 and 102 among the plurality of slits 102 and 102. The plate material portion 107 between the two slits 102-1 and 102-2 is bent so as to be raised by the press in the incision direction between the end points 105a and 106a as a bending line (dotted line L3 in FIG. 3). At this time, the rising angle (bending angle) is set to an optimum angle (elevation angle θ) for exhausting gas molecules as the plate member portion 107 between the slits 102 and 102 is fixed blade 14 (see FIG. 5).

  As shown in FIG. 4, the plate material portion 107 between the slits 102, 102 cut and raised as described above becomes the fixed wing 14. At both ends of the fixed wing 14, there are first and second cuts 105 and 106 which are cut and raised, and the aforementioned small holes 103 and 104 are provided at the end portions of the cuts 105 and 106. . Further, a portion outside the first cut 105 becomes the outer rim portion 15, and a portion inside the second cut 106 becomes the inner rim portion 16.

  By the way, in the above manufacturing method, of the two cuts 105, 106, the first cut 105 enters from one end 102a of one slit 102 toward one end 102a of the adjacent slit 102, and the second cut The notch 105 enters from the other end 102b of the same slit 102 toward the other end 102b of the adjacent slit 102. At this time, there are small holes 103 and 104 which are opened in advance at the points where the first and second cuts 105 and 106 reach and reach, that is, the end points 105a and 106a of the two cuts. For this reason, the positions of the end points 105a and 106a of the first and second cuts are regulated by the small holes 103 and 104.

  Therefore, according to the manufacturing method described above, it is possible to prevent the notches 105 and 106 that enter when the fixed blade 14 is cut and raised from entering excessively, and the fixed blade 14 and the pair of inner and outer rim portions 15 and 16 can be prevented. The width of the connecting portions 108 and 108 (see FIG. 6), that is, the width L4 of the base portion of the fixed wing 14 (specifically, the width from the cut end 105a, 106a to the slit 102 ahead) is made constant. be able to.

  The fixed blade assembly 14n of FIG. 4 manufactured by the above manufacturing method is installed on the inner peripheral surface side of the pump case 1-1. Various installation methods are conceivable. In the vacuum pump P of FIG. 1, as the installation method, as shown in FIG. 1, a plurality of ring-shaped spacers 17 are used, and these spacers 17 are stacked in multiple stages. While installing, the system which clamps the outer rim | limb part 15 of the fixed wing | blade aggregate | assembly 14n between the upper and lower spacers 17 and 17 is employ | adopted.

  According to the vacuum pump P having the fixed blades 14, 14... Produced by the manufacturing method as described above, the width L 4 of the root portion of each fixed blade 14, 14. The strength of the fixed wing 14 is prevented from lowering due to being narrower than the set value, that is, when the first and second cuts 105 and 106 are made longer than necessary. The contact between the fixed blade 14 and the rotary blade 13 due to the atmospheric flow during the operation or the gas flow during normal operation is also prevented.

  In the vacuum pump P of FIG. 1, the substantially lower half of the rotor 6 functions as a screw pump Ps. Hereinafter, a portion functioning as the screw pump Ps will be described.

  The lower side of the rotor 6 is accommodated in a cylindrical screw pump stator 18. The screw pump stator 18 is formed in a tapered cone shape whose inner peripheral portion is reduced in diameter toward the lower side, and has a structure that covers the lower outer periphery of the rotor 6. The screw pump stator 18 is fitted and fixed to the pump case 1-1.

  In the vacuum pump P of FIG. 1, a screw groove 19 is formed on the inner peripheral surface of the screw pump stator 18 as described above, and the lower outer peripheral surface of the rotor 6 facing the screw groove 19 of the screw pump stator 18 is smooth. It is formed on a cylindrical surface. A minute clearance is provided between the screw pump stator 18 and the rotor 6.

  The screw groove 19 is spirally engraved from the upper end to the lower end of the screw pump stator 18. The upstream end 19a (inlet) side of the thread groove 19 communicates with a minute gap between the lowermost rotary blade 13 and the fixed blade 14, and the downstream end 19b (outlet) side of the thread groove 19 is It is configured to communicate with the gas exhaust port 3 side.

  In the case of the vacuum pump shown in FIG. 1, the portion composed of the screw pump stator 18 as described above and the lower outer peripheral surface of the rotor 6 facing the screw groove 19 functions as the screw pump Ps by the rotation of the rotor 6. That is, the gas molecules that have reached the upstream side of the screw pump Ps, that is, the upstream end 19a side of the screw groove 19 due to the function of the turbo molecular pump described above, become viscous from the transition flow due to the interaction between the rotation of the rotor 6 and the screw groove 19. The gas is compressed into a flow, transferred to the gas exhaust port 3 side, and exhausted to the outside through the auxiliary pump (not shown) from the gas exhaust port 3.

  In the above embodiment, an example in which the turbo molecular pump fixed blade is manufactured in the composite vacuum pump has been described. However, the present invention is a so-called all-blade type vacuum pump having only a turbo molecular pump function. Specifically, in the vacuum pump having the structure in which the rotor blades 13 are provided on substantially the entire outer periphery of the rotor 6 shown in FIG.

A sectional view of a vacuum pump. Explanatory drawing of the process to which the manufacturing method of the turbo-molecular pump fixed blade which concerns on this invention is applied. Explanatory drawing of the process to which the manufacturing process of the turbo-molecular pump fixed blade which concerns on this invention is applied. Explanatory drawing of the turbo-molecular pump fixed blade produced through the process of FIG. 2 and FIG. AA line sectional view in FIG. (A) is the C section enlarged view in FIG. 4, (b) is the B section enlarged view in FIG. Explanatory drawing of the conventional turbomolecular pump fixed blade.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exterior case 1-1 Pump case 1-2 Pump base 2 Gas inlet 3 Gas exhaust 4 Stator column 5 Rotor shaft 6 Rotor 7 Boss hole 8 Flange 9 Step part 10 Radial magnetic bearing 10-1 Radial electromagnet target 10-2 Radial electromagnet 10-3 Radial direction displacement sensor 11 Axial magnetic bearing 11-1 Armature disk 11-2 Axial electromagnet 12 Drive motor 12-1 Stator 12-2 Rotor 13 Rotor 14 Fixed vane 14n Fixed vane assembly 15 Outside Rim portion 16 Inner rim portion 17 Spacer 18 Screw pump stator 19 Screw groove 100 Plate material 101 Semi-ring plate material 102 Slit 103 Outer small hole 104 Inner small hole 105 First notch 105a First notch end 106 Second notch 106a second cut end 10 Plate portion 108 connecting portions between the slits (root portion of the fixed wing)
L1 Line segment connecting one end of two adjacent slits L2 Line segment connecting the other ends of two adjacent slits L3 Bending line L4 Width of base of fixed blade P Vacuum pump Pt Turbo molecular pump Ps Screw pump

Claims (2)

A method of manufacturing a turbomolecular pump stationary blade having a structure in which a plurality of stationary blades arranged in a radial manner are integrally connected by a pair of inner and outer rim parts,
The turbo molecular pump fixed blade manufacturing method is as follows:
Forming slits and small holes in the semi-ring plate,
A step of cutting and raising the fixed wing from the half ring-shaped plate material in which the slit and the small hole are formed,
A plurality of the slits are radially formed in the half ring-shaped plate material at regular intervals,
The fixed blade is cut and raised while the first and second cuts are made between two adjacent slits among the plurality of slits, and at the same time, the ending line between the first and second cuts is used as a fold line. Bending so that the plate material part between the two slits rises with a press in the cutting direction,
The method for producing a turbomolecular fixed blade, wherein the small hole is provided in advance at a location that is the end of the first and second cuts when the fixed blade is cut and raised. In a vacuum pump comprising a stationary blade rotating integrally with a rotor around a pump axis and a turbo molecular pump rotating blade fixed at a fixed position alternately in multiple stages,
The turbomolecular pump fixed blades of each stage have a plurality of fixed blades cut and raised so as to be arranged side by side in the radial direction, and when the fixed blades are cut and raised, A vacuum pump characterized by having a small hole at the end of the notch entering both sides.

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