KR20120115204A - Cylindrical fixed member of thread-groove exhaust unit and vacuum pump using same - Google Patents

Abstract

(assignment)
While maintaining the strength of the vacuum pump against the breaking torque, it is possible to reduce the cost, or to form a screw groove exhaust portion having a complicated screw groove whose width, depth and lead angle change in the direction of the rotation axis of the rotating member of the screw groove exhaust portion. Provided is a cylindrical fixing member of the screw groove exhaust pump part which can be easily manufactured on the fixing member side and is adapted to improve the exhaust performance and the compression performance of the entire vacuum pump by employing such screw grooves.
(Solution means) The cylindrical fixing member (screw groove exhaust part stator 18) of the screw groove exhaust part Ps is provided with an outer circumference of the rotating member (approximately the lower half of the rotor 6) of the screw groove exhaust part Ps. It is arrange | positioned so that a spiral screw groove exhaust path S for exhausting gas may be formed between the rotating member. This cylindrical fixing member is divided into two or more divided pieces 18A, 18B in the direction of the rotation axis of the rotating member, and is integrally connected to each divided piece by a fastening means such as a bolt or a joining means such as a shrink fit. It is a structure.

Description

CYLINDRICAL FIXED MEMBER OF THREAD-GROOVE EXHAUST UNIT AND VACUUM PUMP USING SAME}

The present invention relates to a cylindrical fixing member of a screw groove exhaust portion constituting a vacuum pump, and a vacuum pump using the same. Specifically, the invention relates to torque generated when the rotor in the vacuum pump breaks (hereinafter referred to as "breaking torque"). While maintaining the strength of the vacuum pump, it is possible to reduce the cost, or to fix the screw groove of the screw groove exhaust portion in a complicated shape in which the width, the depth of change, the lead angle and the like change in the direction of the rotation axis of the rotating member of the screw groove exhaust portion. It is easy to manufacture on the side, and it is suitable to aim at the improvement of the exhaust performance and compression performance of the whole vacuum pump by employing such a screw groove.

With the large diameter of wafers in recent semiconductor manufacturing apparatuses, the vacuum pump used in this apparatus requires exhaust gas, low attained pressure, high exhaust performance, etc. of a convective gas.

As a vacuum pump that satisfies such a requirement, a composite vane type vacuum pump in which a vane exhaust portion and a screw groove exhaust portion are combined is known (for example, see FIG. 6 of Patent Document 1 for the same type of vacuum pump).

The wing exhaust portion has a structure in which the rotary blades and the fixed blades are alternately arranged in multiple stages, and the operation of applying the momentum in the downward direction to the gas molecules with the rotary blade rotating at high speed, and the gas provided with the momentum in the downward direction The operation in which the molecules are transported to the rotary blade side of the next stage by the fixed blade is repeated and is carried out in multiple stages, whereby the upstream gas molecules are transferred to the downstream screw groove exhaust section.

The screw groove exhaust portion has a rotating member and a cylindrical fixing member arranged to surround the outer circumference of the rotating member, and a spiral screw groove is provided between the cylindrical fixing member and the rotating member by providing a screw groove on the inner circumferential surface of the cylindrical fixing member. It has a structure in which an exhaust passage is formed. The gas molecules transported from the wing exhaust portion as described above enter the screw groove exhaust passage, and the gas molecules are compressed and exhausted by the drag effect on the outer circumferential surface of the screw groove and the rotating member.

However, according to the conventional screw groove exhaust part, the screw groove is provided on the inner circumferential surface of the cylindrical fixing member, thereby forming a screw groove having a complicated shape in which the width, depth, lead angle, etc. change in the direction of the rotation axis of the rotating member. It is difficult to improve the exhaust performance and compression performance of the entire vacuum pump by adopting such a screw groove.

Moreover, the cylindrical fixing member of the said conventional screw groove exhaust part also plays a role of reducing breakdown torque by receiving the fragment when breakage generate | occur | produces inside a vacuum pump. For this reason, the whole cylindrical fixing member of a screw groove exhaust part cannot be manufactured only by the casting with low strength. In order to ensure the strength of the vacuum pump against the breakdown torque, as this type of cylindrical fixing member, an expensive cutting product cut from a high strength material, for example, a material made by forging or extrusion / drawing is not employed. No, the cylindrical fixing member of the screw groove exhaust portion is a factor that causes high cost of the entire vacuum pump.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-115691

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its object is to reduce the cost while maintaining the strength of the vacuum pump with respect to the breaking torque, or to provide the width, depth, The screw groove of complicated shape which changes a lead angle etc. can be manufactured easily in the cylindrical fixing member side of a screw groove exhaust part, and the adoption of such a screw groove is suitable for improving the exhaust performance and compression performance of the whole vacuum pump. To provide a cylindrical fixing member of the screw groove exhaust pump portion and a vacuum pump using the same.

In order to achieve the above object, the present invention is a cylindrical fixing member disposed so as to surround the outer circumference of the rotating member of the screw groove exhaust portion, the spiral screw groove exhaust for exhausting gas between the cylindrical fixing member and the rotating member. A passage is provided, and the said cylindrical fixing member is divided into two or more dividing pieces in the rotating shaft center direction of the said rotating member.

You may comprise so that the division piece of the said cylindrical fixing member may be formed from a different material, respectively.

A screw groove for forming the screw groove exhaust passage may be provided in the cylindrical fixing member, and a configuration in which the lead angle of the screw groove is different in one divided piece and the other divided piece of the cylindrical fixed member may be adopted.

A screw groove for forming the screw groove exhaust passage may be provided in the cylindrical fixing member, and a configuration in which the number of the screw grooves is different in one divided piece and the other divided piece of the cylindrical fixed member may be adopted.

A screw groove for forming the screw groove exhaust passage may be provided in the cylindrical fixing member, and a configuration in which the width of the screw groove is different in one divided piece and the other divided piece of the cylindrical fixed member may be adopted.

A screw groove for forming the screw groove exhaust passage may be provided in the cylindrical fixing member, and a configuration in which the amount of change in the depth of the screw groove is different in one divided piece and the other divided piece of the cylindrical fixed member may be adopted. .

A screw groove for forming the screw groove exhaust passage is provided in the cylindrical fixing member, and in one divided piece of the cylindrical fixed member and the other divided piece, the cylindrical shape is changed by changing the distance from the upper end of the groove of the screw groove to the rotating member. It is also possible to adopt a configuration in which the gap between the fixed member and the rotating member is different.

The cylindrical fixing member may adopt a configuration having a groove formed on its upper surface in the rotational axis direction.

A screw groove for forming the screw groove exhaust passage is provided in each of the divided pieces, and the cylindrical fixing member includes a screw groove positioning means for connecting the screw grooves of one divided piece and the screw grooves of the other divided piece to be continuous. You may comprise so that it may be provided.

The screw groove positioning means comprises an engaging pin which is installed on a divided surface of one divided piece, and an engaging hole formed in the divided surface of another divided piece joined to the divided surface, and the engaging hole is formed. The engagement pin may be inserted into and fitted into the fitting.

The engaging hole is formed of a through hole penetrating the upper and lower end faces of the divided piece, and the engaging pin is inserted and fitted into one end of the through hole, while the other end of the through hole is located at the position of the engaging pin. It may be configured to function as a confirmation window for confirming.

The screw groove aligning means includes a first stepped portion formed on the divided surface of one divided piece, and a second stepped portion formed on the divided surface of the other divided piece joined to the divided surface. It may also be configured to join.

The screw groove positioning means includes an engagement recess formed on the divided surface of one divided piece and an engagement convex formed on the divided surface of the other divided piece joined to the divided surface. You may comprise so that a convex part may engage with the said engagement recessed part.

In the present invention, a configuration in which a work handle for installing one divided piece on the other divided piece is detachably attached to the one divided piece can be adopted.

The said cylindrical fixing member may be comprised so that the lower end part may be supported by the pump base, and the division piece located in the lowest part among the said 2 or more division pieces may be integrated with this pump base by the process of the said pump base.

Moreover, the said cylindrical fixing member is a product mixing prevention means for preventing a product from entering into the clearance gap between the said partition piece and the member located in the outer side, Comprising: The cover part is provided in the outer periphery of the upper end of the partition piece located in the uppermost part of two or more partition pieces. A configuration can be adopted.

In the said invention, the structure which a reinforcing member adheres to the outer peripheral part of the said split piece can also be employ | adopted.

In the present invention, since the cylindrical fixing member adopts a structure in which the cylindrical fixing member is divided into two or more divided pieces in the direction of the rotation axis of the rotating member of the screw groove exhaust portion, as the specific configuration of the cylindrical fixing member, the following (1) or The effect of (2), etc. can be shown.

(1) Each divided piece is formed of a different material according to the required strength, for example, a divided piece of a part requiring strength in particular is a relatively expensive workpiece cut from a material produced by forging or extrusion / drawing. Since the divided pieces of the site | parts which do not need much strength are produced by inexpensive casting, the cost reduction can be aimed at, maintaining the strength of a vacuum pump.

(2) The screw groove processing is performed for each divided piece so that the change in lead angle, number, width, depth, gap with the rotating member, and the like on the inner circumferential surface of the cylindrical fixing member of the screw groove exhaust portion are the axis of rotation of the rotating member. Screw grooves of complicated shape varying in the direction can be produced without high production equipment, and the screw grooves are suitable for improving the exhaust performance and compression performance of the entire vacuum pump.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing of the vacuum pump to which the cylindrical fixing member of the screw groove exhaust part which is one Embodiment of this invention is applied.
2 is an enlarged view of a portion A in FIG. 1;
3 is a plan view of a screw groove exhaust stator (a cylindrical fixing member of the screw groove exhaust portion);
4 is a cross-sectional view of the EE of FIG.
Fig. 5 is a sectional view of another embodiment of the screw groove exhaust unit (a type in which the lead angle of the screw groove is different for each divided piece).
Fig. 6 is a sectional view of another embodiment of the screw groove exhaust portion (type of number of screw grooves different for each divided piece).
Fig. 7 is a sectional view of another embodiment of the screw groove exhaust portion (type of screw grooves having different widths for each divided piece).
Fig. 8 is a sectional view of another embodiment of the screw groove exhaust portion (a type in which the amount of change in the depth of the screw groove is different for each divided piece).
Fig. 9 is a sectional view of another embodiment of the screw groove exhaust portion (a type in which a gap with the rotor is different for each divided piece).
Fig. 10 is a sectional view of another embodiment of a screw groove exhaust portion (a type having grooves for product deposition).
11 is a cross-sectional view of another embodiment of the screw groove exhaust portion (type having screw groove positioning means by the engagement pin and the engagement hole (closed hole)).
Fig. 12 is a sectional view of another embodiment of the screw groove exhaust portion (type having screw groove positioning means by the engagement pin and the engagement hole (through hole)).
FIG. 13 is a side view of another embodiment of the screw groove exhaust portion (type provided with a screw groove positioning means by the stepped portion) seen in the direction indicated by the arrow B in FIG. 2; FIG.
FIG. 14 is a side view of another embodiment of the screw groove exhaust portion viewed from the arrow B direction of FIG. 2 (type provided with screw groove positioning means by the engagement protrusion and the engagement recess); FIG.
Fig. 15 is a side view of another embodiment (type employing a work handle) of the screw groove exhaust portion viewed from the arrow B direction in Fig. 2.
16 is a cross-sectional view of a vacuum pump employing another embodiment (a type in which the lower divided piece is integrally provided with the pump base).
Fig. 17 is a sectional view of another embodiment of a screw groove exhaust portion (a type employing a lid portion).
18 is a cross-sectional view of another embodiment of a screw groove exhaust portion (a type employing a reinforcing member).

EMBODIMENT OF THE INVENTION Hereinafter, the best form for implementing this invention is demonstrated in detail, referring an accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing of the vacuum pump which applied the cylindrical fixing member of the screw groove exhaust part which is one Embodiment of this invention, FIG. 2 is an enlarged view of the A part in FIG. 1, FIG. 3 is a screw groove exhaust stator (fixing member of the screw groove exhaust part). ), And FIG. 4 is a EE cross-sectional view of FIG.

The vacuum pump P of FIG. 1 is used as a part of the vacuum apparatus in a semiconductor manufacturing apparatus or a liquid crystal display panel manufacturing apparatus, for example, and makes the pressure in a vacuum chamber into a predetermined vacuum degree.

The vacuum pump P of this figure has the wing | blade exhaust part Pt which exhausts gas by the rotary vane 13 and the fixed vane 14 in the exterior case 1, and the spiral screw groove exhaust path S And a screw groove exhaust portion Ps for exhausting gas through the cavities, and a drive system for driving these.

<The details of exterior case>

The exterior case 1 is a bottomed cylindrical shape in which the cylindrical pump case 1A and the bottomed cylindrical pump base 1B are integrally connected with bolts in the cylindrical axis direction thereof. The upper end side of the pump case 1A is opened as the gas intake port 2, and the gas exhaust port 3 is provided on the lower end side surface of the pump base 1B.

The gas intake port 2 is a vacuum container in which high vacuum is omitted, for example, a process chamber of a semiconductor manufacturing apparatus, by a bolt (not shown) provided on the flange 1C of the upper edge of the pump case 1A. Is connected to. The gas exhaust port 3 is connected to communicate with an auxiliary pump (not shown).

<The details of support drive system>

In the center part of the pump case 1A, a cylindrical stator column 4 having various electrical components is provided, and the stator column 4 is installed so that its lower end is screwed onto the pump base 1B. have.

The rotor shaft 5 is provided inside the stator column 4, and the upper end part of the rotor shaft 5 faces the direction of the gas intake port 2, and the lower end part faces the direction of the pump base 1B. It is arranged to. The upper end of the rotor shaft 5 is provided so as to protrude upward from the cylindrical upper end surface of the stator column 4.

The rotor 6 is provided outside the stator column 4. The rotor 6 is housed in the pump case 1A and has a cylindrical shape surrounding the outer periphery of the stator column 4. This rotor 6 is integrated with the rotor shaft 5 described above. As an example of the integrated structure of the rotor 6 and the rotor shaft 5, in the vacuum pump P of FIG. 1, the flange 8 with the boss hole 7 is provided inside the upper end of the rotor 6; Moreover, the edge part 9 is formed in the outer periphery of the upper end part of the rotor shaft 5. The upper end of the rotor shaft 5 above the end 9 is fitted into the boss hole 7 of the flange 8 so that the flange 8 and the end 9 are screwed to the rotor 6. And the rotor shaft 5 are integrated.

The rotor composed of the rotor shaft 5 and the rotor 6 is supported by the radial magnetic bearing 10 and the axial magnetic bearing 11 so as to be rotatable in the radial direction and the axial direction. In this state, the rotor shaft ( It is rotationally driven by the drive motor 12 with 5) as the axial center.

The drive motor 12 is a structure which consists of the stator 12A and the rotor 12B, and is provided in the substantially center vicinity of the rotor shaft 5. The stator 12A of this drive motor 12 is provided inside the stator column 4, and the rotor 12B of this drive motor 12 is integrally mounted on the outer peripheral surface side of the rotor shaft 5. have.

The radial magnetic bearings 10 are arranged in pairs one by one in the top and bottom of the drive motor 12, and the axial magnetic bearings 11 are arranged in the lower end side of the rotor shaft 5.

The two sets of radial magnetic bearings 10 and 10 each have a radial electromagnet target 10A attached to the outer circumferential surface of the rotor shaft 5 and a plurality of radial electromagnets 10B provided on the inner side surface of the stator column 4 opposite thereto. ) And radial direction displacement sensor 10C. The radial electromagnet target 10A consists of a laminated steel plate which laminated | stacked the steel plate of high permeability material, and the radial electromagnet 10B magnetically attracts the rotor shaft 5 in radial direction through the radial electromagnet target 10A. The radial direction displacement sensor 10C detects the radial displacement of the rotor shaft 5. And the rotating body which consists of the rotor shaft 5 and the rotor 6 by controlling the excitation current of the radial electromagnet 10B based on the detected value (radial displacement of a rotor shaft) by the radial direction displacement sensor 10C is Floating support is carried out magnetically at a predetermined position in the radial direction.

The axial magnetic bearing 11 includes a disk-shaped armature disk 11A attached to the outer periphery of the lower end of the rotor shaft 5, an axial electromagnet 11B facing up and down with the armature disk 11A interposed therebetween, and a rotor shaft. It has 11 A of axial direction displacement sensors provided in the position a little distance from the lower end surface of (5).

The armature disk 11A is made of a material having a high permeability, and the upper and lower axial electromagnets 11B are configured to suck the armature disk 11A magnetically from its vertical direction. The axial direction displacement sensor 11C detects the axial displacement of the rotor shaft 5. And the rotating body which consists of the rotor shaft 5 and the rotor 6 by controlling the excitation current of the upper and lower axial electromagnets 11B based on the detection value (axial displacement of a rotor shaft) in 11 A of axial direction displacement sensors. Is floated and supported by a magnetic force at an axial predetermined position.

<Detailed configuration of the wing exhaust part Pt>

In the vacuum pump P of FIG. 1, the substantially upper half of the rotor 6 functions as a wing | blade exhaust part Pt. Hereinafter, this vane exhaust part Pt is demonstrated in detail.

On the outer peripheral surface of the substantially upper half of the rotor 6, a plurality of rotary vanes 13 are integrally provided. These rotary vanes 13 are radially stretched around the rotary shaft center of the rotor 6 or the shaft center of the outer case 1 (hereinafter referred to as the "pump shaft center"). On the other hand, a plurality of fixed blades 14 are provided on the inner circumferential surface side of the pump case 1A, and these fixed blades 14 are arranged radially around the pump shaft center. The rotary blades 13 and the fixed blades 14 are alternately arranged in multiple stages along the pump shaft center to form the blade exhaust portion Pt.

Any rotary blade 13 is a blade-shaped cutting product which is cut and formed integrally with the outer diameter machining portion of the rotor 6, and is inclined at an angle that is optimal for exhausting gas molecules. Both fixed vanes 14 are also inclined at an angle that is optimal for exhausting gas molecules.

<Exhaust Operation of Wing Exhaust Pt>

By the start of the drive motor 12, the rotor shaft 5, the rotor 6, and the plurality of rotary vanes 13 rotate at a high speed integrally, and the uppermost rotary vanes 13 enter the gas intake port 2. The momentum in the downward direction is given to one gas molecule. The gas molecules having the downward momentum are transported to the rotary vane 13 at the next stage by the fixed vane 14. By repeatedly applying the momentum to the gas molecules and conveying them in multiple stages, the gas molecules on the gas intake port 2 side are located upstream of the screw groove exhaust portion Ps (more specifically, the screw groove exhaust passages described later). It exhausts so that it may sequentially move to the upstream inlet 19A of (S).

<Detailed structure of screw groove exhaust part Ps>

In the vacuum pump P of FIG. 1, the substantially lower half of the rotor 6 functions as the screw groove exhaust part Ps. Hereinafter, this screw groove exhaust part Ps is demonstrated in detail.

The lower half of the rotor 6 is a portion that rotates as the rotating member of the screw groove exhaust part Ps, and is inside the cylindrical screw groove exhaust part stator 18 that is a cylindrical fixing member of the screw groove exhaust part Ps. By being accommodated, it arrange | positions so that it may oppose the screw groove exhaust part stator 18 through the predetermined gap G like FIG. The gap G is about 0.7 mm.

The screw groove exhaust part stator 18 (cylindrical fixing member of the screw groove exhaust part Ps) forms a screw groove 19 whose depth is changed into a tapered cone shape having a small hardening downward. The lower end part is supported by the pump base 1B.

In this screw groove exhaust part Ps, by forming the screw groove 19 in the inner peripheral surface of the said screw groove exhaust part stator 18, about half of this screw groove 19 and the rotor 6 which opposes this are approximately It is comprised so that the spiral-shaped screw groove exhaust path S may be formed in the outer peripheral surface of this. Although not shown, by forming the screw groove on the outer circumferential surface of approximately the lower half of the rotor 6, a spiral screw groove exhaust passage is formed from the screw groove and the inner circumferential surface of the screw groove exhaust part stator 18 opposite thereto. You may also

In addition, the screw groove exhaust part stator 18 of this screw groove exhaust part Ps is divided into two divided pieces 18A, 18B in the rotation axis center direction of the rotor 6 (rotation member of the screw groove exhaust part Ps). ), And each of the divided pieces 18A, 18B is integrally connected by fastening means such as bolts or joining means such as shrink fitting. By the division of the screw groove exhaust part stator 18, the screw groove 19 formed in the inner peripheral surface is also divided in the same direction, and the divided screw groove 19 is provided in each of the divided pieces 18A and 18B. have. The screw groove exhaust part stator 18 is not limited to two divisions of the present example, and can be divided into two or more divisions such as three divisions and four divisions. Moreover, a well-known fitting structure, such as the fitting D of unevenness | corrugation, can be employ | adopted as the connection part of two division pieces 18A, 18B.

In this vacuum pump P, as one Embodiment of the said screw groove exhaust part Ps, the two division pieces 18A and 18B which comprise the screw groove exhaust part stator 18 are each formed from a different material, (See FIG. 4). Specifically, the upper divided piece 18A, which is close to the center of the rotor 6 and susceptible to damage when the rotor 6 breaks, is made of a material of high strength, specifically forging or extrusion / drawing. Although it is a relatively expensive cutting workpiece cut out from the material, the lower divided piece 18B, which is hard to be affected by such a material, is used as an inexpensive casting product, thereby reducing the cost while maintaining the strength of the vacuum pump.

In this vacuum pump P, while forming the screw groove 19 in the inner peripheral surface of the above-mentioned screw groove exhaust part stator 18, the outer peripheral surface of substantially lower half of the rotor 6 which opposes the screw groove 19 is formed. By forming into a smooth cylindrical surface, the spiral screw groove exhaust passage S is formed between the screw groove exhaust part stator 18 (cylindrical fixing member) and the rotor 6 (rotating member). In addition, although five screw grooves 19 were provided in the screw groove exhaust part Ps like FIG. 3, the number can be changed suitably as needed.

The screw groove exhaust passage S is spirally provided from the upper end to the lower end of the screw groove exhaust part stator 18. The upstream inlet 19A of the screw groove exhaust passage S communicates with a minute gap between the lowermost rotary vane 13 and the fixed blade 14, and the downstream outlet of the screw groove exhaust passage S is provided. The 19B side is configured to communicate with the gas exhaust port 3 side. In addition, in this screw groove exhaust part Ps, the depth of the screw groove 19 is exhausted, in order to convey, while compressing gas by the drag effect in the outer peripheral surfaces of the screw groove 19 and the rotor 6. It is set so that it may be deepest on the upstream inlet 19A side of the passage S, and shallowest on the downstream outlet 19B side.

<Exhaust Behavior of Screw Groove Exhaust Section>

As described above, when the rotor shaft 5, the rotor 6, and the plurality of rotary vanes 13 are integrally rotated at high speed by the start of the drive motor 12, the above-described exhaust operation of the vane exhaust part Pt is performed. The gas molecules reaching the upstream inlet 19A of the screw groove exhaust passage S enter the screw groove exhaust passage S and are transferred by the drag effect at the outer circumferential surface of the rotor 6 and the screw groove 19. While moving to the gas exhaust port 3 while being compressed into viscous flow, it is finally exhausted to the outside through an auxiliary pump (not shown).

<Other embodiment of screw groove exhaust part>

5-18 is explanatory drawing of other embodiment of the screw groove exhaust part Ps.

The screw groove exhaust part Ps of FIG. 5 uses the screw groove exhaust part stator 18 (cylindrical fixing member of the screw groove exhaust part Ps) like the embodiment of FIG. The screw groove 19 is provided in each division piece 18A, 18B. In the upper divided piece 18A and the lower divided piece 18B, the lead angle θ of the screw groove 19 has a different configuration such as 30 degrees and 15 degrees. In addition, the lead angle (theta) of the screw groove 19 is not limited to the said example, It can change suitably as needed.

The screw groove exhaust part Ps of FIG. 6 uses the screw groove exhaust part stator 18 (cylindrical fixing member of the screw groove exhaust part Ps) like the embodiment of FIG. The screw grooves 19 are provided in each of the divided pieces 18A and 18B, and the number of the screw grooves 19 is different in the divided pieces 18A on the upper side and the divided pieces 18B on the lower side. It consists.

The screw groove exhaust part Ps of FIG. 7 uses the screw groove exhaust part stator 18 (cylindrical fixing member of the screw groove exhaust part Ps) similarly to the embodiment of FIG. 1 in two divided pieces 18A and 18B. The screw groove 19 is provided in each divided piece 18A, 18B, and the width | variety of the screw groove 19 is L1, in the upper divided piece 18A and the lower divided piece 18B. Another configuration is adopted as in L2.

The screw groove exhaust part Ps of FIG. 8 uses the screw groove exhaust part stator 18 (cylindrical fixing member of the screw groove exhaust part Ps) like the embodiment of FIG. And the grooves 190 and 191 are provided in each of the divided pieces 18A and 18B, and the depth of the screw grooves 19 in the upper divided piece 18A and the lower divided piece 18B. The amount of change is configured differently. In FIG. 8, the screw groove 190 is changed to become shallow at the same gradient in the upper divided piece 18A, and the depth of the screw groove 191 does not change in the lower divided piece 18B (change amount = 0). Although the form is employ | adopted, it is not limited to this example. Although not shown, a form in which the screw groove 191 of the lower divided piece 18B is changed to be shallower with a gentle gradient can be adopted as compared with the screw groove 190 of the upper divided piece 18A. It may be.

As for the screw groove exhaust part Ps of FIG. 9, the screw groove exhaust part stator 18 (cylindrical fixing member of the screw groove exhaust part Ps) is divided into two divided pieces 18A and 18B like embodiment of FIG. The screw groove 19 is provided in each of the divided pieces 18A and 18B, and the rotor from the upper end of the groove of the screw groove 19 in the upper divided piece 18A and the lower divided piece 18B. By changing the distance to (6), the gap between the screw groove exhaust part stator 18 (cylindrical fixing member of the screw groove exhaust part Ps) and the rotor 6 (rotating member of the screw groove exhaust part Ps) is obtained. The other form is employ | adopted like this G1 and G2. In FIG. 9, since the product of the lower divided piece 18B having a high pressure tends to deposit relatively, this gap is set to G1 &lt; G2. The gap G1 is about 0.7 mm and the gap G2 is about 1 mm.

As for the screw groove exhaust part Ps of FIG. 10, the groove | channel 20 formed in the rotation axis center direction is provided in the upper surface of the screw groove exhaust part stator 18 (cylindrical fixing member of the screw groove exhaust part Ps), The rotary vane 13 when the product deposits on the upper surface of the screw groove exhaust part stator 18 by depositing a product generated by the gas exhausted from the inside of the pump and solidifying in a high pressure part or the like in the groove 20. It aims to prevent contact with. In the example of FIG. 10, since the screw groove exhaust part stator 18 is divided into two divided pieces 18A and 18B, the groove 20 is provided on the upper surface of the upper divided piece 18A. In addition, although not shown, when the screw groove exhaust part stator 18 is divided into three or more divided pieces, the groove 20 is installed on the upper surface of the uppermost divided piece closest to the rotary vane 13. do.

In the divided structure of the screw groove exhaust part stator 18 demonstrated above, it is necessary to connect the screw groove 19 provided in each divided piece 18A, 18B so that it may continue. If the screw groove 19 is stopped in the middle, the gas compression / exhaust operation by the above-described drag effect is performed until it reaches the downstream outlet 19B from the upstream inlet 19A of the screw groove exhaust passage S. This is because it cannot be done. On the other hand, since the screw groove 19 is formed in the inner peripheral surfaces of the divided pieces 18A and 18B, and the connection part of the screw groove 19 is in a position which is hard to be seen by an operator, the connection work of the screw groove 19 is difficult.

Therefore, when employ | adopting the division | segmentation structure of the screw groove exhaust part stator 18 demonstrated above, it is preferable to employ | adopt the screw groove position alignment means 21 shown in any one of FIG. All of these screw groove positioning means 21 are means for arranging the screw groove 19 of the upper divided piece 18A and the screw groove 19 of the lower divided piece 18B so as to be continuous. The configuration is as follows.

The screw groove position alignment means 21 in FIG. 11 includes an engagement pin 21A made of a tapered pin that stands on a divided surface of the lower divided piece 18B, and an upper divided piece joined to the divided surface ( In addition to the engaging holes 21B formed in the divided surface of 18A), the engaging pins 21A are inserted into and fitted into the engaging holes 21B, so that both of the divided pieces 18A and 18B are fitted. Positioning of the screw groove 19 is performed. In addition, in the example of FIG. 11, in order to make it easy to insert the engagement pin 21A into the engagement hole 21B, the chamfering process is given in the edge part of the engagement hole 21B.

Moreover, as another embodiment, the lower division piece which 21 A of said engagement pins stands up in the divided surface of 18 A of upper division pieces, and the said engagement hole 21B joins the division surface is installed further. It is also possible to adopt a configuration formed by drilling in 18B. In addition, a plurality of sets of the above-described engagement pins 21A and the engagement holes 21B may be provided. In the case where two sets are provided, the radial positions of the upper and lower divided pieces 18A and 18B are also determined, so that the fitting D described above can be omitted. In this case, in contrast to the case where one of the engagement pins 21A is folded, the engagement structure of the stepped portions 21D and 21E shown in FIG. 13 described later, or the engagement protrusions 21F shown in FIG. It is preferable to employ the engaging structure of the fitting recess 21G.

The engagement hole 21B may be a closed hole as illustrated in FIG. 11 described above, but may be a through hole penetrating the upper and lower end faces of the upper divided piece 18A as shown in FIG. 12. In this case, the engagement pin 21A is inserted and fitted to the lower end of the through hole, while the upper end of the through hole functions as a confirmation window 21C for confirming the position of the engagement pin 21A.

As an example of the engagement hole 21B as described above, when the through hole as shown in FIG. 12 is employed, the partitioning piece 18A on the upper side is inserted by fitting the engagement pin 21A into the engagement hole 21B. When aligning the screw groove 19 in the lower portion 18B on the lower side, the operator can check the position of the engagement pin 21A from the confirmation window 21C, so that the alignment operation becomes easy.

The screw groove positioning means 21 of FIG. 13 divides the 1st step part 21D formed in the dividing surface of 18 A of upper division pieces, and the dividing part 18B of the lower side joined to the dividing surface. In addition to the second stepped portion 21E formed on the surface, these stepped portions 21D and 21E are located at at least two positions and are joined to each other to join each other, so that the screw grooves 19 of the two divided pieces 18A and 18B are joined. ) Is aligned. Although the figure is omitted, the stepped portions 21D and 21E may be inclined.

The screw groove position alignment means 21 of FIG. 14 divides the engagement convex part 21F formed in the dividing surface of 18 A of upper division pieces, and the division part 18B of the lower side joined to the dividing surface. In addition to the engagement recessed portion 21G formed on the surface, these engagement projections 21F and the engagement recessed portion 21G are located at at least one position and are engaged with each other to engage each other, thereby resulting in both divided pieces 18A. , 18B) is to be aligned with the screw groove 19.

In the division structure of the screw groove exhaust part stator 18 demonstrated above, although the operation | movement which installs the upper division piece 18A on the lower division piece 18B is performed, the operation handle shown in FIG. 15 in the operation | work By using (22), the workability of installation is improved.

The handle 22 has a form (eye bolt shape) in which a ring-shaped gripping portion 22B is provided at the head of the bolt 22A. And the screw hole (illustration omitted) is formed in the upper surface of 18 A of upper division pieces, and this handle 22 is divided | segmented by inserting the bolt 22A of the handle 22 in this screw hole. Removably attached to the piece 18A. Then, when the above installation work is completed, the handle 22 is removed from the upper divided piece 18A and reused in the next installation work. In addition, you may employ | adopt other means other than the said bolt 22A about the means which attaches the handle 22 to 18 A of upper division pieces.

As for the screw groove exhaust part Ps demonstrated above, the screw groove exhaust part stator 18 (cylindrical fixing member of the screw groove exhaust part Ps) is divided into two division pieces 18A and 18B, and the lower side The divided piece 18B is supported by the pump base 1B (see FIG. 1 and the like). In this structure, the lower part piece 18B can be integrally provided with the pump base 1B as shown in FIG. 16 by the process of the pump base 1B. In addition, although illustration is abbreviate | omitted, when dividing the screw groove | channel exhaust part stator 18 into three or more division pieces, the division piece located in the lowest part is provided integrally with the pump base 1B.

According to the integral structure of the pump base 1B and the division piece 18B as mentioned above, a component point reduction can be aimed at. In addition, since the pump base 1B and the lower divided piece 18B do not have a joining surface which is a heat transfer obstacle, the screw groove exhaust part stator is formed by a water cooling tube (not shown) incorporated in the pump base 1B. 18) It becomes possible to cool the whole efficiently.

About the screw groove exhaust part Ps demonstrated above, for example, as shown in FIG. 17, the outer peripheral part of 18 A of upper division pieces is cut off, and it is comprised so that it may become easy to bend and deform the upper division pieces 18A by breaking torque. can do. In this case, a product may enter the clearance gap 30 which arises between the divided piece 18A and the member located in the outer side (in the example of FIG. 17, pump base 1B), and the clearance gap 30 may fill up. . As the gap 30 is filled, the divided pieces 18A are hardly deformed. The gap 30 is caused by cutting the outer peripheral portion of the divided piece 18A.

In order to solve the problems as described above, in the screw groove exhaust portion Ps of FIG. 17, as the product mixing prevention means for preventing the product from entering the gap 30, the upper peripheral portion of the upper divided piece 18A is provided. The cover part 40 is provided. Although not illustrated, when the screw groove exhaust part stator 18 is divided into three or more divided pieces, the outer peripheral portion of the divided pieces positioned at least at the top is easily cut and bent and deformed. In addition, the cover portion 40 as described above is provided on the outer peripheral portion of the upper end of the divided piece located at the top.

By the way, if the strength of the cover part 40 is too high, the effect by the bending deformation of the upper divided piece 18A will be impaired, and the cover part 40 is comprised by low intensity | strength by making thickness as thin as possible, for example. It is desirable to.

As a specific structure of the cover part 40, upper division, such as a structure which installs and fixes a thin plate with the fixing member 40A, such as a screw, on the upper end surface of 18 A of upper division pieces as shown in FIG. It is good also as a part different from piece 18A. In addition, as described above, when the outer peripheral portion of the upper divided piece 18A is cut off, the portion to be the cover portion 40 is left as shown in FIG. 18, so that the cover portion 40 is divided into the upper divided piece 18A. You may comprise as an integrated component with the. In addition, although FIG. 17 is the example which employ | adopted the cover part 40 in the structure which integrated the lower parting piece 18B with the pump base 1B, such a cover part 40 has the lower parting piece 18B. The structural example (refer FIG. 1 etc.) which is not integrated with the pump base 1B can also be employ | adopted.

By the way, the above-mentioned clearance 30 makes it easy to bend and deform | transform the upper divided piece 18A, and it is easy to fracture by comparatively weak force. If it breaks easily with weak force, the effect by the bending deformation of 18 A of upper side fragments cannot fully be exhibited. For this reason, in the screw groove exhaust part Ps of FIG. 18, high strength members, such as CFRP, are attached as the reinforcement member 50 to the outer peripheral part of 18 A of upper division pieces, specifically, the site | part which formed the clearance gap 30. Doing. 18 is an example in which the reinforcing member 50 is adopted in the structural example in which the lower divided piece 18B is integrated with the pump base 1B, but such a reinforcing member 50 is the lower divided piece 18B. The structure which is not integrated with this pump base 1B (refer FIG. 1 etc.) can also be employ | adopted.

In the screw groove exhaust part Ps of FIGS. 5-18 demonstrated above, each division piece 18A, 18B may be formed with a different material like FIG. 5 to 9, screw grooves 19, 190 and 191 having a complicated shape can be appropriately combined as necessary, whereby a screw groove having a more complicated shape can be employed.

In all the embodiments described above, as the concrete configuration of the screw groove exhaust part stator 18 (fixing member of the screw groove exhaust part Ps), such a screw groove exhaust part stator 18 has a rotor 6 (screw groove double). Since the structure divided | segmented into two or more division pieces 18A, 18B in the rotation axis direction of the base Ps rotation part) is employ | adopted, the effect of (1) or (2), etc. can be exhibited below.

(1) Each of the divided pieces is formed of different materials according to the required strength, for example, the divided pieces of the site requiring particularly strength are made of relatively expensive workpieces cut from materials made by forging or extrusion / drawing. Since the divided pieces of the site | parts which do not need much strength are produced by inexpensive casting, the cost reduction can be aimed at, maintaining the strength of a vacuum pump.

(2) The thread groove processing is performed separately for each divided piece so that the lead angle θ, the number, the widths L1 and L2, the amount of change in the inner circumferential surface of the screw groove exhaust part stator 18, or the rotor 6 ) Can be produced without the need for advanced production equipment, and the screw grooves of a complicated shape in which the gap of the rotor 6 changes in the direction of the rotation axis of the rotor 6 can be manufactured without the use of high production equipment. Can be planned.

1: Outer case 1A: Pump case
1B: Pump base 1C: Flange
2: gas intake port 3: gas exhaust port
4: stator column 5: rotor shaft
6: rotor 7: boss hole
8: Flange 9: End
10: radial magnetic bearing 10A: radial electromagnet target
10B: Radial Electromagnet 10C: Radial Directional Displacement Sensor
11: Axial magnetic bearing 11A: Amateur disc
11B: Axial Electromagnet 11C: Axial Directional Displacement Sensor
12: drive motor 12A: stator
12B: rotor 13: rotary wing
14: fixed wing 18: screw groove exhaust section stator
18A, 18B: Part 19, 190, 191: Screw groove
19A: Upstream inlet of screw groove exhaust passage
19B: downstream outlet of screw groove exhaust passage
20: Home for product deposition
21: Screw home position alignment means
21A: Engagement pin 21B: Engagement hole
21C: confirmation window 21D: first step
21E: 2nd step part 21F: Engaging convex part
21G: Engaging recess 22: Handle
22A: Bolt 22B: Holding part
30: clearance of a split piece and a member located outside
40: cover part 50: reinforcing member
D: Fitting G, G1, G2: Gap between rotor and screw groove exhaust stator
L1, L2: Width of screw groove P: Vacuum pump
Pt: Wing exhaust part Ps: Screw groove exhaust part
S: Screw groove exhaust passage θ: Lead angle of screw groove

Claims (18)

A cylindrical fixing member disposed to surround the outer circumference of the rotating member of the screw groove exhaust portion,
A spiral screw groove exhaust passage for exhausting gas is provided between the cylindrical fixing member and the rotating member, and the cylindrical fixing member is divided into two or more divided pieces in the rotation axis direction of the rotating member. The tubular fixing member of the screw groove exhaust part characterized by the above-mentioned. The method according to claim 1,
The cylindrical fixing member of the screw groove exhaust part, wherein the divided pieces of the cylindrical fixing member are each formed of different materials. The method according to claim 1,
Screw grooves for forming the screw groove exhaust passage are provided in each of the divided pieces,
A cylindrical fixing member of a screw groove exhaust portion, wherein the lead angle of the screw groove is different from the one divided piece and the other divided piece. The method according to claim 1,
Screw grooves for forming the screw groove exhaust passage are provided in each of the divided pieces,
A cylindrical fixing member of a screw groove exhaust portion, characterized in that the number of screw grooves is different in the one divided piece and the other divided piece. The method according to claim 1,
Screw grooves for forming the screw groove exhaust passage are provided in each of the divided pieces,
A cylindrical fixing member of a screw groove exhaust portion, wherein a width of a screw groove is different in the one divided piece and the other divided piece. The method according to claim 1,
Screw grooves for forming the screw groove exhaust passage are provided in each of the divided pieces,
A cylindrical fixing member of a screw groove exhaust portion, characterized in that the change amount of the depth of the screw groove is different from the one divided piece and the other divided piece. The method according to claim 1,
Screw grooves for forming the screw groove exhaust passage are provided in each of the divided pieces,
And the gap between the cylindrical fixing member and the rotating member is different in the one divided piece and the other divided piece by changing the distance from the upper end of the groove of the screw groove to the rotating member. The method according to claim 1,
The cylindrical fixing member has a groove formed in an upper surface thereof in a groove in a rotational axis direction. The method according to claim 1,
Screw grooves for forming the screw groove exhaust passage are provided in each of the divided pieces,
The cylindrical fixing member,
And a thread groove positioning means for continuously connecting the screw groove of one split piece and the screw groove of another split piece to each other. The method according to claim 9,
The screw groove positioning means,
The engagement pin is formed on the division surface of one divided piece, and the engagement hole formed in the division surface of the other division piece joined to the division surface, and the engagement pin is inserted into the engagement hole. A cylindrical fixing member of a screw groove exhaust portion, which is adapted to be fitted. The method of claim 10,
The engaging hole consists of a through hole penetrating the upper and lower end faces of the divided piece, and the engaging pin is inserted and fitted into one end of the through hole, while the other end of the through hole is the position of the engaging pin. A cylindrical fixing member of a screw groove exhaust portion, functioning as a confirmation window for confirming that. The method according to claim 9,
The screw groove positioning means,
And a first stepped portion formed on the divided surface of one divided piece, and a second stepped portion formed on the divided surface of the other divided piece joined to the divided surface, wherein the two stepped portions are joined to each other. Cylindrical fixing member of the thread groove exhaust. The method according to claim 9,
The screw groove positioning means,
The engagement convex portion formed on the divided surface of one divided piece and the engagement convex portion formed on the divided surface of the other divided piece joined to the divided surface, and the engagement convex portion is fitted to the engagement recessed portion. A cylindrical fixing member of a screw groove exhaust portion, characterized in that it is intended to be provided. The method according to claim 1,
A working handle for installing one split piece on another split piece is detachably attached to the split piece. The method according to claim 1,
The lower end portion of the cylindrical fixing member is supported by a pump base,
A cylindrical fixing member of a screw groove exhaust portion, wherein the divided piece positioned at the bottom of the two or more divided pieces is provided integrally with the pump base by processing the pump base. The method according to claim 1,
The cylindrical fixing member,
A product groove preventing means for preventing a product from entering into a gap between the split piece and a member positioned outside the screw piece, wherein a screw portion is provided on the outer periphery of the upper end of the split piece positioned at the top of the split pieces. The cylindrical fixing member of the exhaust part. The method according to claim 1,
A reinforcing member is attached to an outer circumferential portion of the divided piece. The vacuum pump using the cylindrical fixing member of the screw groove exhaust part of any one of Claims 1-17.

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