WO2015076313A1

WO2015076313A1 - Rotation mechanism, machine tool, and semiconductor manufacturing device

Info

Publication number: WO2015076313A1
Application number: PCT/JP2014/080689
Authority: WO
Inventors: 中村　剛
Original assignee: 日本精工株式会社
Priority date: 2013-11-20
Filing date: 2014-11-19
Publication date: 2015-05-28

Abstract

A rotation mechanism is provided with: a housing; a shaft; a bearing for rotatably supporting the shaft; a first rotation member that is disposed at a first end of the shaft and has an overhang projecting radially outward beyond a first hole and to a side portion of the housing, said overhang facing the side portion of the housing across a first clearance having a predetermined size; a second rotation member that is disposed at a second end of the shaft, projects radially outward beyond a second hole, and faces the housing at the second end side across a second clearance having a predetermined size; a first aperture that opens into the housing radially outward the first hole, faces the first rotation member, and extends along the circumferential direction of the first hole to supply gas into the first clearance; and a second aperture that opens into the housing radially outward the second hole of the housing, faces the second rotation member, and extends along the circumferential direction of the second hole to supply gas into the second clearance.

Description

Rotating mechanism, machine tool and semiconductor manufacturing equipment

The present invention relates to a rotation mechanism, a machine tool, and a semiconductor manufacturing apparatus.

A rotation mechanism that rotates a rotary stage or rotates a tool or a workpiece is used in a transfer device, a semiconductor manufacturing device, a machine tool, or the like. In such a rotation mechanism, a seal using a gas is sometimes used for the rotating part in order to suppress entry of liquid or foreign matter from the outside (for example, Patent Document 1).

JP-A-9-150336

By the way, there is a rotating mechanism that rotates by attaching a rotating body to both sides of the shaft. The technique described in Patent Document 1 is intended for a rotating mechanism in which a rotating body is attached to one end of a shaft. For the rotating mechanism that rotates by attaching a rotating body to both sides of the shaft, the rotating portion is sealed using gas. There is room for improvement.

An object of the present invention is to provide a rotation mechanism, a machine tool, and a semiconductor manufacturing apparatus suitable for rotating a rotating part by attaching a rotating body to both sides of a shaft when the rotating part is sealed with gas.

The present invention includes a housing, a shaft that is inserted through a first hole and a second hole provided in the housing, a bearing that is installed in the housing and rotatably supports the shaft, and a first end of the shaft A projecting portion that is provided in a portion and rotates together with the shaft and projects to the outside of the first hole in the radial direction and to the side portion of the housing, and the overhanging portion has a predetermined size with respect to the side portion of the housing. A first rotating member facing each other with a first gap, and a second end portion provided at a second end portion of the shaft, rotating together with the shaft, and projecting radially outward of the second hole. A second rotating member facing the housing on the side with a second gap of a predetermined size, facing the first rotating member by opening radially outward of the first hole of the housing, and Around the first hole A first opening that supplies gas to the first gap, opens radially outward of the second hole of the housing, faces the second rotating member, and the second And a second opening that extends along a circumferential direction of the hole and supplies gas to the second gap.

This rotating mechanism supplies gas from the first opening to the first gap on the first rotating member side, and supplies gas from the second opening to the second gap on the second rotating member side. Since this gas flows out of the housing through the first gap and the second gap, the first rotating member and the second rotating member, which are rotating bodies, are sealed. As described above, this rotation mechanism is suitable for a structure in which a rotating body is attached and rotated on both sides of the shaft when the rotating portion is sealed with gas.

It is preferable that the first rotating member is disposed above the second rotating member. The first gap is formed between the side portion of the housing and the overhanging portion of the first rotating member, and when the first gap on the first rotating member side is disposed above, the gas is below the first opening. The outlet is located. For this reason, when the first rotary member provided with the first gap is disposed above the second rotary member, when the liquid enters the first gap when the gas supply is stopped, The liquid is easily discharged from the first gap.

It is preferable that the first gap is larger than the dimension of the first opening in the radial direction of the shaft, and the second gap is larger than the dimension of the second opening in the radial direction of the shaft. By doing in this way, gas can be uniformly discharged | emitted from the 1st opening and 2nd opening along the circumferential direction of a 1st rotation member and a 2nd rotation member. Further, since the first gap is larger than the dimension of the first opening in the radial direction of the shaft, and the second gap is larger than the dimension of the second opening in the radial direction of the shaft, the gas flowing out from the first opening and the second opening Is reliably guided to the first gap and the second gap. For this reason, this rotation mechanism can seal the part in which the 1st rotation member and the 2nd rotation member are provided reliably.

The space between the first rotating body and the housing between the first hole and the first opening includes a portion smaller than the dimension of the first opening in the radial direction of the first hole, and the second It is preferable that a portion smaller than the dimension of the second opening in the radial direction of the first hole is included between the second rotating body and the housing between the hole and the second opening. By doing in this way, since the part smaller than the dimension of the 1st opening and the part smaller than the dimension of the 2nd opening exhibit a sealing function, the liquid permeated into the housing from the 1st crevice and the 2nd crevice. Even in this case, the liquid can be prevented from reaching the shaft portion.

It is preferable that a portion of the housing adjacent to the first gap has a groove along the circumferential direction of the first hole. With such a structure, even when the rotation center axes of the first rotating member and the second rotating member are inclined with respect to the direction in which gravity acts, the liquid accumulated in the first gap is discharged to the outside of the housing. can do.

It is preferable that a portion of the second rotating member adjacent to the second gap has a groove along the circumferential direction of the second hole. With such a structure, even when the rotation center axes of the first rotating member and the second rotating member are inclined with respect to the direction in which gravity acts, the liquid accumulated in the second gap is discharged to the outside of the housing. can do.

The first opening is formed between two parts, extends in a direction orthogonal to the rotation center axis of the shaft, and has a gap smaller than that of the first opening. Gas is supplied, and the second aperture is formed between the two parts in the second opening, extends in a direction orthogonal to the rotation center axis of the shaft, and has a smaller interval than the second opening. It is preferable that the gas is supplied through the section. In this way, there are fewer management items for the accuracy of the two parts forming the first throttle part and the two parts forming the second throttle part.

It is preferable that a first spacer is provided between two parts forming the first throttle part, and a second spacer is provided between two parts forming the second throttle part. By using the first spacer and the second spacer, it is possible to further reduce the accuracy management items of the two parts forming the first throttle part and the two parts forming the second throttle part.

Since the machine tool according to the present invention includes the above-described rotation mechanism, the machine tool is suitable for being attached to a rotating body on both sides of the shaft for rotation when sealing the rotating portion with gas.

Since the semiconductor manufacturing apparatus according to the present invention includes the above-described rotation mechanism, it is suitable for a device in which a rotating body is attached and rotated on both sides of the shaft when the rotating portion is sealed with gas.

The present invention can provide a rotation mechanism, a machine tool, and a semiconductor manufacturing apparatus suitable for rotating a rotating portion by attaching a rotating body on both sides of a shaft when the rotating portion is sealed with gas.

FIG. 1 is a cross-sectional view illustrating a rotation mechanism according to the first embodiment. FIG. 2 is a cross-sectional view illustrating a rotation mechanism according to a modification of the first embodiment. FIG. 3 is a cross-sectional view illustrating a rotation mechanism according to the second embodiment. FIG. 4 is a cross-sectional view illustrating a rotation mechanism according to the third embodiment. FIG. 5 is a cross-sectional view illustrating a rotation mechanism according to a modification of the third embodiment. FIG. 6 is a cross-sectional view illustrating a rotation mechanism according to the fourth embodiment. FIG. 7 is a cross-sectional view illustrating a rotation mechanism according to the fifth embodiment. FIG. 8 is a cross-sectional view illustrating a rotation mechanism according to a modification of the fifth embodiment.

(Embodiment 1)
Hereinafter, a mode for carrying out the present invention (hereinafter referred to as a first embodiment) will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing a rotation mechanism according to the first embodiment. FIG. 1 shows a cross section in which the rotation mechanism 1 is cut along a plane including the rotation center axis Zr of the rotation mechanism 1 and parallel to the rotation center axis Zr. The direction indicated by arrow G in FIG. 1 is the direction in which gravity acts. The rotation mechanism 1 is a mechanical element that transmits rotation, and is applied to, for example, a transport device, a semiconductor manufacturing apparatus, or a flat panel display manufacturing apparatus used in a special environment such as a machine tool or a vacuum chamber. Here, as an example, the case where the rotation mechanism 1 is a spindle unit including a spindle as a rotation axis will be described. However, the application target of the rotation mechanism 1 is not limited to this.

The rotating mechanism 1 includes a housing 2, a shaft 4,

bearings

7A, 7B, and 7C, a first rotating member 5A as a rotating body, a second rotating member 5B as a rotating body, a first opening 11A, 2 openings 11B. The housing 2 is a member that houses the

bearings

7A, 7B, 7C, the electric motor 3, and the like. In the present embodiment, the housing 2 includes a main body 2S that is a cylindrical member, a first structure 2FA provided at one end of the main body 2S, and a second provided at the other end of the main body 2S. And a structure 2FB. The main body 2S, the first structure 2FA, and the second structure 2FB are a part of the housing 2. In the present embodiment, the main body 2S is a cylindrical member and has a through hole 2SI from one end to the other end, that is, from the first structure 2FA to the second structure 2FB.

The first structure 2FA has a first member 2FAS and a second member 2FAR, and is a structure in which these are combined. The second structure 2FB has a first member 2FBS and a second member 2FBR, and is a structure in which these are combined. The first structure 2FA and the second structure 2FB are both plate-like members. In the present embodiment, the shapes of the first structure 2FA and the second structure 2FB are circular in plan view, but these shapes are not limited to a circle.

The first member 2FAS and the second member 2FAR included in the first structure 2FA are both annular members. The 2nd member 2FAR is attached to this from the one end part of the 1st member 2FAS, and is provided in the radial direction outer side of the 1st member 2FAS. The first member 2FBS and the second member 2FBR included in the second structure 2FB are both annular members. The second member 2FBR is attached to the inside in the radial direction of the first member 2FBS.

In the radial direction of the hole 2HA, a predetermined gap 12A is provided between the first member 2FAS and the second member 2FAR of the first structure 2FA. This gap 12A is open to the surface 2FAP of the first structure 2FA facing the first rotating member 5A. This opening is the first opening 11A. The first opening 11A faces the first rotating member 5A. A groove 9A is provided along the circumferential direction on the inner circumferential surface of the second member 2FAR. The groove 9A is connected to the gap 12A. The groove 9A is connected to the first gas passage 10A.

In the radial direction of the hole 2HB, a predetermined gap 12B is provided between the first member 2FBS and the second member 2FBR of the second structure 2FB. The gap 12B opens on a surface 2FBP of the second structure 2FB that faces the second rotating member 5B. This opening is the second opening 11B. The first opening 11B faces the second rotating member 5B. A groove 9B is provided along the circumferential direction on the inner peripheral surface of the second member 2FBR. The groove 9B is connected to the gap 12B. The groove 9B is connected to the second gas passage 10B.

The first structure 2FA includes a first hole 2HA including the rotation center axis Zr of the shaft 4 and penetrating in the thickness direction. The second structure 2FB includes a second hole 2HB that includes the rotation center axis Zr of the shaft 4 and penetrates in the thickness direction. The shaft 4 is an output shaft of the rotation mechanism 1, and is provided in both the housing 2, more specifically, the first hole 2 HA included in the first structure 2 FA of the housing 2 and the second hole 2 HB included in the second structure 2 FB. Inserted.

The bearing 7A is installed on the inner peripheral part of the first member 2FAS of the first structure 2FA in the housing 2, in this embodiment, via the annular preloading member 8, and rotatably supports the shaft 4. The

bearings

7B and 7C are installed on the inner periphery of the housing 2, in the present embodiment, on the second rotating member 5B side of the main body 2S, and rotatably support the shaft 4. The

bearings

7B and 7C are attached to the second end 4TB side of the shaft 4. In the present embodiment, the shaft 4 is supported on the housing 2 by the three

bearings

7A, 7B, and 7C, but the number of bearings is not limited to two.

Bearings

7A, 7B, and 7C include an outer ring 7a, rolling elements 7b, and an inner ring 7c. The inner ring 7c is disposed on the radially inner side of the outer ring 7a. Thus, in this embodiment, all the

bearings

7A, 7B, and 7C are rolling bearings. The rolling element 7b is disposed between the outer ring 7a and the inner ring 7c. In the bearing 7A, the outer ring 7a is in contact with the inner wall of the first member 2FAS of the first structure 2FA included in the housing 2. In the

bearings

7B and 7C, the outer ring 7a is in contact with the inner wall of the through hole 2SI included in the main body 2S of the housing 2. With such a structure, the

bearings

7A, 7B, and 7C are attached to the housing 2. In the present embodiment, both the

bearings

7A, 7B, and 7C are ball bearings, but the types of the

bearings

7A, 7B, and 7C as rolling bearings are not limited to ball bearings. In the present embodiment, the

bearings

7A, 7B, and 7C are all rolling bearings, but may be sliding bearings, hydrostatic bearings, or magnetic bearings. For example, the hydrostatic bearing is provided with an exhaust groove along the circumferential direction of the first hole 2HA on the inner peripheral surface of the first hole 2HA included in the first member 2FAS of the first structure 2FA. This can be realized by providing an exhaust groove along the circumferential direction of the second hole 2HB on the inner peripheral surface of the second hole 2HB of the second member 2FBR.

The first rotating member 5 A is provided at the first end 4 TA of the shaft 4 and rotates together with the shaft 4. In the present embodiment, the first rotating member 5A is attached to the shaft 4 via the first support member 6A. The second rotating member 5B is attached to the shaft 4 via the second support member 6B. The second rotating member 5 B is provided at the second end 4 TB of the shaft 4 and rotates together with the shaft 4. As described above, the first rotating member 5 A and the second rotating member 5 B rotate together with the shaft 4.

The first rotating member 5A is opposed to the side portion of the first structure 2FA with the first gap 13A having a predetermined size. In the present embodiment, the first rotating member 5A has an overhang portion 5FA in which the outer peripheral portion on the first structure 2FA side extends to the second member 2FAR side of the first structure 2FA. The overhang portion 5FA and the second member 2FAR overlap in the direction of the rotation center axis Zr of the first rotation member 5A. 13 A of 1st clearance gaps are the inner periphery of side part 2FRAS of 2nd member 2FAR of 1st structure 2FA, and extension part 5FA of 1st rotation member 5A in the part where overhang | projection part 5FA and 2nd member 2FAR overlapped. The part 5WI faces the part.

The second rotating member 5B faces the housing 2 with a second gap 13B having a predetermined size. In the present embodiment, the first member 2FBS of the second structure 2FB included in the housing 2 has a protruding portion 2FBE in which the side portion on the second rotating member 5B side extends to the second rotating member 5B side. Yes. The projecting portion 2FBE of the first member 2FBS and the second rotating member 5B overlap with each other in the direction of the rotation center axis Zr of the second rotating member 5B. The second gap 13B is a portion where the second rotating member 5B and the overhanging portion 2FBE of the second member 2FAR overlap with each other, the side portion 5BE of the second rotating member 5B, and the first member 2FBS of the second structure 2FB. This is a portion facing the inner peripheral surface 2FBI of the overhang portion 2FBE.

In the first rotating member 5A, an object is placed on the surface 5APS opposite to the first end 4TA of the shaft 4. In the present embodiment, the first rotating member 5A is a plate-like member and has a circular plan view. The first rotating member 5A extends to the outside in the radial direction of the first hole 2HA provided in the first structure 2FA of the housing 2. As shown in FIG. 1, the portion of the first hole 2HA that protrudes to the outside in the radial direction faces the housing 2 with a predetermined gap 14A. The gap 14A is formed between a surface 2FAP of the housing 2 facing the first rotating member 5A of the first member 2FAS and the second member 2FAR and a surface 5APR of the first rotating member 5A facing the first structure 2FA. Is done.

In the second rotating member 5B, an object is placed on the surface 5BPS opposite to the second end 4TB of the shaft 4. In the present embodiment, the second rotating member 5B is a plate-like member and has a circular plan view. The second rotating member 5B extends to the outside in the radial direction of the hole 2HB provided in the second structure 2FB of the housing 2. As shown in FIG. 1, the portion of the hole 2 HB that projects to the outside in the radial direction is opposed to the housing 2 with a predetermined gap 14 B. The gap 14B is formed between the surface 2FBP of the housing 2 facing the second rotating member 5B of the first member 2FBS and the second member 2FBR and the surface 5BPR of the second rotating member 5B facing the second structure 2FB. Is done.

The first gas passage 10A is provided in a portion of the housing 2 that faces the first rotating member 5A, more specifically, in the second member 2FAR of the first structure 2FA of the housing 2. The first gas passage 10A opens to the side portion 2FYA of the second member 2FAR of the first structure 2FA. The second gas passage 10 B is provided in a portion facing the second rotating member 5 B of the housing 2, more specifically, in the first member 2 FBS of the second structure 2 FB of the housing 2. The second gas passage 10B opens to the side portion 2FYB of the first member 2FBS of the second structure 2FB.

The first gas passage 10A and the second gas passage 10B are connected to the air supply device 50. The air supply device 50 supplies gas (air in this embodiment) to the

grooves

9A and 9B via the first gas passage 10A and the second gas passage 10B. The air supply device 50 is, for example, a pump. The gas from the first gas passage 10A flows out from the first opening 11A to the gap 14A and is supplied to the first gap 13A. The gas from the second gas passage 10B flows out from the second opening 11B to the gap 14B and is supplied to the second gap 13B. Gas is supplied to the first gap 13 A and the second gap 13 B, and the gas flows out of the housing 2, thereby sealing (sealing) the inside and the outside of the housing 2.

In the present embodiment, the rotation mechanism 1 has one first gas passage 10A and one second gas passage 10B, but the number thereof is not limited. When the rotation mechanism 1 has a plurality of first gas passages 10A and second gas passages 10B, respectively, it is preferable that these are provided at equal intervals around the rotation center axis Zr.

An electric motor 3 is provided inside the housing 2. The electric motor 3 includes a rotor 3R and a stator 3S provided on the radially outer side of the rotor 3R. The stator 3S is attached to the inner wall of the through hole 2SI included in the main body 2S. The rotor 3R is provided between the first end 4TA and the second end 4TB of the shaft 4. With such a structure, the rotor 3R, the shaft 4, the first rotating member 5A, and the second rotating member 5B rotate integrally around the rotation center axis Zr. In the present embodiment, the type of the electric motor 3 is not limited.

In the present embodiment, dust generated in the

bearings

7A, 7B, and 7C is collected by the gas passing through the first hole 2HA and the second hole 2HB. When the inside of the through hole 2SI is sealed, the gas does not easily pass through the first hole 2HA and the second hole 2HB, so that the inside of the through hole 2SI is not sealed. The main body 2 S of the housing 2 has an exhaust passage 19 that connects the outside and the through hole 2 SI and discharges the gas in the through hole 2 SI to the outside of the housing 2. The exhaust passage 19 is preferably provided with a throttle valve. Since this throttle valve suppresses the flow rate of the gas passing through the exhaust passage 19, an increase in the amount of gas supplied from the first gas passage 10A and the second gas passage 10B is suppressed.

In this embodiment, as described above, the gas flowing out from the first opening 11A and the second opening 11B flows out of the housing 2 after being supplied to the first gap 13A and the second gap 13B. For this reason, intrusion of foreign matter from the outside of the rotating mechanism 1 between the shaft 4 and the housing 2, entry of foreign matter into the

bearings

7A, 7B, 7C and dust generation from the inside of the housing 2 flow out to the outside. It is suppressed. Dust generation from the inside of the housing 2 includes, for example, dust generation from the

bearings

7A, 7B, and 7C and dust generation from the electric motor 3.

If the exhaust passage 19 is narrow, long, or both, the exhaust resistance increases, and thus there is a possibility that gas will not be easily discharged from the through hole 2SI. As a result, there is a possibility that the gas in the through-hole 2SI is caught in the gas flow flowing out from the first opening 11A and the second opening 11B, and the dust generation of the

bearings

7A, 7B, 7C flows out of the housing 2. is there. In order to avoid this, an exhaust device may be connected to the exhaust passage 19 or the exhaust passage 19 may be connected to a decompressed space so as to ensure the flow rate of the gas flowing through the exhaust passage 19. In this way, it is possible to reduce the possibility that dust from the

bearings

7A, 7B, and 7C flows out of the housing 2.

The rotation mechanism 1 can use mechanical bearings that do not require gas supply, such as rolling bearings or sliding bearings, for the

bearings

7A, 7B, and 7C. When rolling bearings are used for the

bearings

7A, 7B, and 7C, the displacement of the shaft 4 in the

gaps

14A and 14B directions due to reasons other than loads from the objects mounted on the first rotating member 5A and the second rotating member 5B is reduced. It is suppressed.

In the present embodiment, the size tsa of the first gap 13A is larger than the width ta of the first opening 11A, that is, the dimension of the first opening 11A in the radial direction of the hole 2HA. The width ta of the first opening 11A is equal to the width of the gap 12A. The size tsb of the second gap 13B is larger than the width tb of the second opening 11B, that is, the dimension of the second opening 11B in the radial direction of the hole 2HB. The width tb of the second opening 11B is equal to the width of the gap 12B. As described above, the first opening 13A has a size tsa larger than the width ta of the first opening 11A and the second gap 13B has a size tsb larger than the width tb of the second opening 11B. The gas flowing out from 11A can be efficiently guided to the first gap 13A, and the gas flowing out from the second opening 11B can be efficiently guided to the second gap 13B, so that the sealing effect can be reliably exhibited.

For example, a slot stop of a gas bearing can be used for the first opening 11A and the second opening 11B. The width ta of the first opening 11A and the width tb of the second opening 11B are, for example, about several μm to several tens of μm. The size tsa of the first gap 13A and the size tsb of the second gap 13B vary depending on the width ta of the first opening 11A and the width tb of the second opening 11B. For the first opening 11 A and the second opening 11 B, various throttle types for hydrostatic bearings, such as a porous throttle or a self-made throttle, can be used.

The first opening 11A and the second opening 11B are formed along the circumferential direction of the hole 2HA and the hole 2HB. For this reason, the first opening 11A can inject gas uniformly in the circumferential direction between the first rotating member 5A and the first structure 2FA, and the second opening 11B has the second opening 11B. Gas can be uniformly injected in the circumferential direction between the rotating member 5B and the second structure 2FB. In order to increase the width ta of the first opening 11A and the width tb of the second opening 11B for the purpose of uniformly injecting the gas, an adjustment device for suppressing the flow rate of the gas flowing into the gap 12A and the gap 12B Can be provided in the first gas passage 10A and the second gas passage 10B or in the passage connected thereto.

The first opening 11A and the gap 12A are formed between the first member 2FAS and the second member 2FAR of the first structure 2FA. That is, the first opening 11A and the gap 12A are formed between the two members. The second opening 11B and the gap 12B are formed between the first member 2FBS and the second member 2FBR of the second structure 2FB. That is, the first opening 11A and the gap 12A and the second opening 11B and the gap 12B are formed between the two members. Thus, the first opening 11A and the second opening 11B do not allow gas to flow out from the gap between the rotating body and the housing. For this reason, with respect to the first member 2FAS and the second member 2FAR of the first structure 2FA and the first member 2FBS and the second member 2FBR of the second structure 2FB, management of their dimensional accuracy and geometrical tolerances such as cylindricity are given. Can be relaxed. As a result, the manufacturing cost of the first structure 2FA and the second structure 2FB can be reduced. Further, by forming the first opening 11A and the gap 12A and the second opening 11B and the gap 12B by, for example, connecting two members by fitting, the management of these dimensions becomes relatively easy. Furthermore, by forming the first structure 2FA and the second structure 2FB from two members, replacement of parts can be facilitated.

In addition, a material that is excellent in terms of corrosion resistance with respect to the atmosphere outside the housing 2 to be sealed, but can not be employed in terms of workability. For example, in the first structure 2FA, a material excellent in corrosion resistance that could not be used so far is applied to the second member 2FBR provided outside the housing 2, or applied to the first member 2FBS of the second structure 2FB. You can do it.

The first gap 13A that exhibits the sealing function is a portion where the protruding portion 5FA of the first rotating member 5A and the second member 2FAR of the first structure 2FA overlap. The second gap 13B that exhibits the sealing function is a portion where the side portion 5BE of the second rotating member 5B and the inner peripheral surface 2FBI of the overhang portion 2FBE of the first member 2FBS of the second structure 2FB overlap. . The gap 12A reduces the amount of gas supplied from the first opening 11A, and the gap 12B reduces the amount of gas supplied from the second opening 11B.

The rotation mechanism 1 can suppress the intrusion of liquid or the like by the first gap 13A and the second gap 13B even when the supply of gas from the air supply device 50 is stopped. The same applies when liquid or the like is sprayed from the outside of the housing 2 to the first rotating member 5A and the second rotating member 5B.

In the present embodiment, the first rotating member 5A provided with the first gap 13A is disposed above the second rotating member 5B provided with the second gap 13B. That is, the first rotating member 5A is disposed on the side opposite to the direction of gravity and the second rotating member 5B is disposed on the direction of gravity. With this arrangement, when liquid or the like flows into the first gap 13A on the first rotating member 5A side, the liquid is easily discharged from below the first gap 13A (the direction in which gravity acts) by the action of gravity. . Further, in the second gap 13B on the second rotating member 5B side, the surface 5BPS of the second rotating member 5B opposite to the second end portion 4TB of the shaft 4 faces downward. Therefore, when liquid or the like flows into the second gap 13B, the liquid is easily discharged from the second gap 13B due to the action of gravity. Furthermore, even when the supply of gas from the air supply device 50 shell is stopped, the intrusion of liquid or the like can be suppressed.

(Modification)
FIG. 2 is a cross-sectional view illustrating a rotation mechanism according to a modification of the first embodiment. FIG. 2 shows a cross section of the rotation mechanism 1a taken along a plane including the rotation center axis Zr of the rotation mechanism 1a and parallel to the rotation center axis Zr. As shown in FIG. 1, in the rotation mechanism 1 of the first embodiment, the second member 2 FBR of the second structure 2 FB is in contact with the end of the main body 2 S of the housing 2. The second member 2FBRa of the second structure 2FBa is different from the end of the main body 2S of the housing 2a. For this purpose, the first member 2FBBSa of the second structure 2FBa has an overhanging portion 2FBF in which a portion in contact with the main body portion 2S side projects radially inward. The second member 2FBRa of the second structure 2FBa is in contact with the main body portion 2S of the housing 2a via the overhang portion 2FBF. Even with such a structure, the rotating mechanism 1 a can obtain the same operations and effects as the rotating mechanism 1. Further, in the rotation mechanism 1a, the overhang portion 2FBF can position the second member 2FBRa of the second structure 2FBa in the direction of the rotation center axis Zr.

As described above, the

rotation mechanisms

1 and 1a according to the first embodiment and the modifications thereof are suitable for rotating the shaft by attaching a rotating body to both sides of the shaft 4 when sealing the rotating portion with gas. The configurations of the first embodiment and the modifications thereof can be applied as appropriate in the following embodiments. In this case, only a part of the configuration of the first embodiment and its modifications may be applied, or all the configurations may be applied.

(Embodiment 2)
FIG. 3 is a cross-sectional view illustrating a rotation mechanism according to the second embodiment. FIG. 3 shows a cross section of the rotation mechanism 1b taken along a plane including the rotation center axis Zr of the rotation mechanism 1b and parallel to the rotation center axis Zr. In the rotation mechanism 1b, between the first rotation member 5Ab and the housing 2b between the first hole 2HA and the first opening 11A, the dimension of the first opening 11A in the radial direction of the first hole 2HA, that is, the width ta. Includes a small portion 18A (hereinafter, referred to as a small gap portion 18A as appropriate). Further, the portion between the second rotation member 5Bb and the housing 2 between the second hole 2HB and the second opening 11B is a portion smaller than the dimension of the second opening 11B in the radial direction of the second hole 2HB, that is, the width tb. (Hereinafter referred to as small gap portion 18B as appropriate).

The small gap portion 18A on the first structure 2FAb side is a gap between the first member 2FASb of the first structure 2FA and the first rotating member 5Ab. The size of the small gap portion 18A, that is, the interval between the surface 2FAP of the first member 2FASb and the surface 5APR of the first rotating member 5Ab is tc. The small gap portion 18B on the second structure 2FBb side is a gap between the second member 2FBRb and the second rotating member 5Bb of the second structure 2FB. The size of the small gap portion 18B, that is, the interval between the surface 2FBP of the second member 2FBRb and the surface 5BPR of the second rotating member 5Bb is td.

The rotating mechanism 1b has a large gap portion 15A having a gap larger than the small gap portion 18A between the small gap portion 18A on the first structure 2FAb side and the first opening 11A. The size of the large gap portion 15A is te. The large gap portion 15A is connected to the first gap 13A. The rotating mechanism 1b has a large gap portion 15B having a gap larger than the small gap portion 18B between the small gap portion 18B on the second structure 2FBb side and the second opening 11B. The size of the large gap portion 15B is tf. The large gap portion 15B is connected to the second gap 13B.

On the first rotating member 5Ab side, the relationship between the size te of the large gap portion 15A, the width ta of the first opening 11A, and the size tc of the small gap portion 18A is te> ta> tc. On the second rotating member 5Bb side, the relationship between the size tf of the large gap portion 15B, the width tb of the second opening 11B, and the size td of the small gap portion 18B is tf> tb> td.

As described above, the width ta of the first opening 11A and the width tb of the second opening 11B are several μm to several tens μm. The size tc of the small gap portion 18A and the size tf of the small gap portion 18B are about several μm to 20 μm, and the size te of the large gap portion 15A and the size tf of the large gap portion 15B are more than several tens of μm. large.

The gas flowing out from the first opening 11A to the large gap portion 15A is supplied to the first gap 13A and seals this portion. The gas flowing out from the second opening 11B to the large gap portion 15B is supplied to the second gap 13B and seals this portion. In the rotating mechanism 1b, liquid can be accumulated between the first rotating member 5Ab and the first structure 2FA or between the second rotating member 5Bb and the second structure 2FBb due to an abnormality in the external environment of the housing 2b. There is sex.

In the rotation mechanism 1b, since the small gap portion 18A and the small gap portion 18B exhibit a sealing function, even when liquid enters the large gap portion 15A and the large gap portion 15B from the first gap 13A and the second gap 13B, This liquid can be prevented from reaching the portion of the shaft 4. In particular, it is preferable because the liquid can be effectively prevented from entering the portion of the shaft 4 even when the gas supply to the first opening 11A and the second opening 11B is stopped.

As described above, the rotation mechanism 1b according to the second embodiment is suitable for a structure in which a rotating body is attached and rotated on both sides of the shaft 4 when the rotating portion is sealed with gas. The configuration of the second embodiment can be applied as appropriate in the following embodiments. In this case, only a part of the configuration of the second embodiment may be applied, or all the configurations may be applied.

(Embodiment 3)
FIG. 4 is a cross-sectional view illustrating a rotation mechanism according to the third embodiment. FIG. 4 shows a cross section in which the rotation mechanism 1c is cut along a plane including the rotation center axis Zr of the rotation mechanism 1c and parallel to the rotation center axis Zr. The rotation mechanism 1 and the rotation mechanism 1c described above have the second gap 13B extending in a direction parallel to the rotation center axis Zr. The rotation mechanism 1c of Embodiment 3 has a second gap 13Bc between the surface 5BPR of the second rotation member 5Bc and the surface 2FBP of the second structure 2FBc of the housing 2c. That is, the rotation mechanism 1c is different in that it has a second gap 13Bc extending in a direction intersecting (orthogonal in this example) with the rotation center axis Zr.

For example, the first member 2FBSc needs to have high strength. Since the second member 2FBRc is highly likely to come into contact with the liquid, corrosion resistance and the like are necessary. By extending the second gap 13Bc in the direction intersecting (orthogonal in this example) with the rotation center axis Zr, each of the first member 2FBSc and the second member 2FBRc of the second structure 2FBc is required. A material having characteristics can be used. In this example, a high-strength material can be used for the first member 2FBSc, and a highly corrosion-resistant material can be used for the second member 2FBRc. As a result, the performance of the second structure 2FBc is improved.

In the present embodiment, the second rotating member 5Bc has a member 5BI and a member 5BJ. The member 5BI is attached to the shaft 4, and the member 5BJ is attached to the outside of the member 5BI. The second opening 11B is provided at a position facing the member 5BJ. The member 5BI attached to the shaft 4 does not directly contact the environment outside the rotating mechanism 1c because the member 5BJ is attached to the outside. Since the member 5BJ directly contacts the environment outside the rotation mechanism 1c, corrosion resistance is required. The member 5BI is required to be strong because the rotational force from the shaft 4 is transmitted.

When the second rotating member 5B is formed of the two members 5BI and 5BJ, a material having properties suitable for the members 5BI and 5BI can be used. In this example, a high-strength material can be used for the member 5BI, and a material having high corrosion resistance can be used for the member 5BJ. As a result, the performance of the second rotating member 5Bc is improved. The diameter DR of the second rotating member 5Bc is larger than the diameter DS of the second structure 2FBc, but the size of both is not limited to this. In the present embodiment, the second gap 13Bc extends in a direction intersecting the rotation center axis Zr. However, the first gap 13A shown in FIG. 1 is arranged in a direction intersecting (for example, orthogonal to) the rotation center axis Zr. It may be extended.

(Modification)
FIG. 5 is a cross-sectional view illustrating a rotation mechanism according to a modification of the third embodiment. FIG. 5 shows a cross section of the rotation mechanism 1d taken along a plane including the rotation center axis Zr of the rotation mechanism 1d and parallel to the rotation center axis Zr. The rotation mechanism 1d extends the protruding portion 5FAd of the first rotation member 5Ad to the main body 2Sd of the housing 2d. With such a structure, the first gap 13A is formed between the inner peripheral portion 5WI of the overhang portion 5FAd and the side portion 2FSAS of the first member 2FASd and the side portion 2FRAS of the second member 2FRAS of the first structure 2FAd. It is formed.

The end of the main body 2Sd of the housing 2d on the second rotating member 5Bd side has an overhang 2SHd that projects to the position of the second rotating member 5Bd. The first member 2FBSd and the second member 2FBRd of the second structure 2FBd are attached to the inner peripheral portion 2SI of the overhang portion 2SHd. The diameter DR of the second rotating member 5Bd is smaller than the inner diameter DI of the overhang portion 2SHd. For this reason, the side part 5BJd of the second rotating member 5Bd faces the inner peripheral part 2SI of the overhang part 2SHd. A second gap 13Bd is formed between the second rotating member 5Bd and the second member 2FBRd of the second structure 2FBd. The diameter DR of the second rotating member 5Bd is smaller than the inner diameter DI of the overhang portion 2SHd.

With such a structure, the degree of freedom in selecting the material of the parts for forming the first opening 11A and the gap 12A connected thereto and the second opening 11B and the gap 12B connected thereto is improved. Can do. The parts described above are the first member 2FASd and the second member 2FARd of the first structure 2FAd, and the first member 2FBSd and the second member 2FBRd of the second structure 2FBd.

As described above, the

rotation mechanisms

1c and 1d according to the third embodiment and the modifications thereof are suitable for rotating by attaching a rotating body to both sides of the shaft 4 when sealing the rotating portion with gas. Although the third embodiment and the modifications thereof have been described, the configurations of the third embodiment and the modifications can be applied as appropriate in the following embodiments. In this case, only a part of the configuration of the third embodiment and its modification may be applied, or all the configurations may be applied.

(Embodiment 4)
FIG. 6 is a cross-sectional view illustrating a rotation mechanism according to the fourth embodiment. FIG. 6 shows a cross section of the rotation mechanism 1e taken along a plane that includes the rotation center axis Zr of the rotation mechanism 1e and is parallel to the rotation center axis Zr. The rotating mechanism 1e according to the fourth embodiment includes a groove 16 along the circumferential direction of the first hole 2HA in a portion adjacent to the first gap 13A of the housing 2e, and is adjacent to the second gap 13B of the second rotating member 5Be. The point which has the groove | channel 17 along the circumferential direction of 2nd hole 2HB in the part to perform differs from the rotation mechanism 1 of Embodiment 1 mentioned above. The groove 16 extends to the position of the overhanging portion 5FAe of the first rotating member 5Ae in the direction of the rotation center axis Zr. In the present embodiment, the second rotating member 5Be is formed of two members, a member 5BIe and a member 5BJe, but the second rotating member 5Be may be a single member.

In Embodiments 1 to 3, the

rotation mechanisms

1, 1b, 1c, and 1d are all installed so that the rotation center axis Zr is parallel to the direction in which gravity acts. In the present embodiment, the rotation mechanism 1e is installed so that the rotation center axis Zr intersects with the direction in which gravity acts (in the present embodiment, it is orthogonal). If liquid is contained in the external atmosphere of the housing 2e, there is a possibility that the liquid accumulates in the first gap 13A and the second gap 13B. For this reason, the rotation mechanism 1e has the groove 16 in the portion adjacent to the first gap 13A of the housing 2e, that is, the second member 2FBRe included in the first structure 2FAe in the present embodiment. Further, the rotation mechanism 1e has a groove 17 in a portion adjacent to the second gap 13B of the second rotation member 5Be, that is, a portion facing the first member 2FBSe included in the second structure 2FBe in the present embodiment.

The groove 16 discharges the liquid accumulated in the first gap 13A to the outside of the housing 2e. The groove 17 discharges the liquid accumulated in the second gap 13B to the outside of the housing 2e. As a result, it is possible to suppress liquid from accumulating in the first gap 13A and the second gap 13B. The rotating mechanism 1e according to the fourth embodiment is suitable for a rotating portion that is attached with a rotating body on both sides of the shaft 4 and rotated when the rotating portion is sealed with gas. In particular, the rotation center axis Zr intersects with the direction of gravity action. It is suitable for. Although the fourth embodiment has been described, the configuration of the fourth embodiment can be appropriately applied to the following embodiments. In this case, only a part of the configuration of the fourth embodiment may be applied, or all the configurations may be applied.

(Embodiment 5)
FIG. 7 is a cross-sectional view illustrating a rotation mechanism according to the fifth embodiment. FIG. 7 shows a cross section of the rotation mechanism 1f taken along a plane including the rotation center axis Zr of the rotation mechanism 1f and parallel to the rotation center axis Zr. In the rotation mechanism 1f of the fifth embodiment, the first member 2FARf and the second member 2FASf of the first structure 2FAf are in contact with each other at their outer peripheral portions. The second member 2FASf has an annular groove 9Af extending along the circumferential direction on the radially outer side. In the first member 2FARf and the second member 2FASf, the surface 2FARP of the first member 2FARf and the second member 2FASf surface 2FASP are in contact with each other on the radially outer side of the groove 9Af.

30A of 1st aperture | diaphragm | squeeze parts are formed between 1st member 2FARf and 2nd member 2FASf. 30 A of 1st aperture | diaphragm | squeeze parts are formed between two components, ie, 1st member 2FARf, and 2nd member 2FASf, and are extended in the direction orthogonal to the rotation center axis Zr of the rotation mechanism 1f. The first member 2FARf has a step in a portion of the surface 2FAEP and a portion radially inward of the surface 2FAEP in order to form the first diaphragm portion 30A. 30 A of 1st aperture | diaphragm | squeeze parts are connected with the clearance gap 12A inside the radial direction of 1st structure 2FAf, and are connected with groove | channel 9Af at the radial inside of 1st structure 2FAf. The groove 9Af is connected to the first gas passage 10A. With such a structure, the gas supplied from the air supply device 50 flows into the first throttle portion 30A through the first gas passage 10A and the groove 9Af. The gas that has flowed into the first throttle portion 30A flows out of the first opening 11A through the gap 12A. The interval between the first aperture portions 30A is about several μm to several tens of μm, and is smaller than the interval between the gaps 12A.

The rotation mechanism 1f is provided with a protruding portion 2ST, a part of which protrudes in the direction of the rotation center axis Zr at the end of the main body 2Sf on the side where the second structure 2FBf is attached. The second structure 2FBf is attached to the outside of the protrusion 2ST. A part of the surface 2FBPf of the second structure 2FBf and a part of the end surface 2SP on the side where the second structure 2FBf of the main body 2Sf is attached are in contact with each other on the outside in the radial direction. A second diaphragm 30B is formed between the end surface 2SP and the second structure 2FBf. 30 A of 2nd aperture | diaphragm | squeeze parts are formed between main-body part 2SF and 2nd structure 2FBf, and are extended in the direction orthogonal to the rotation center axis Zr of the rotation mechanism 1f. The second structure 2FBf has a step between a portion of the surface 2FBP and a portion radially inward of the surface 2FBP in order to form the second diaphragm portion 30B. The interval between the second aperture portions 30B is about several μm to several tens of μm, and is smaller than the interval between the gaps 12B.

The second structure 2FBf has an annular groove 9Bf extending along the circumferential direction on the radially outer side. The second throttle portion 30B is connected to the gap 12B on the radially inner side of the second structure 2FBf, and is connected to the groove 9Bf on the radially inner side of the second structure 2FBf. The groove 9Bf is connected to the second gas passage 10B. With such a structure, the gas supplied from the air supply device 50 flows into the second throttle portion 30B through the second gas passage 10B and the groove 9Bf. The gas that has flowed into the second throttle portion 30B flows out of the second opening 11B through the gap 12B.

The rotation mechanism 1f requires only the flatness and level difference of the surface 2FARP for the first member 2FARf and only the flatness of the surface 2FASP for the second member 2FASf in order to form the first diaphragm portion 30A. . The second structure 2FBf only requires the flatness and the level difference of the surface 2FBPf in order to form the second diaphragm portion 30B. For this reason, since the rotation mechanism 1f does not need to manage the diameter tolerance of the first member 2FARf, the second member 2FASf, and the second structure 2FBf, there is an advantage that the number of management items for the component accuracy can be reduced. As a result, the yield is improved.

(Modification)
FIG. 8 is a cross-sectional view illustrating a rotation mechanism according to a modification of the fifth embodiment. FIG. 8 shows a cross section of the rotating mechanism 1g taken along a plane including the rotating center axis Zr of the rotating mechanism 1e and parallel to the rotating center axis Zr. The rotating mechanism 1g of this modification includes a first spacer 31A between the first member 2FARf and the second member 2FASf of the rotating mechanism 1f of the fifth embodiment, and is between the main body 2Sf and the second structure 2FBf. The difference is that the second spacer 31B is provided. In the rotation mechanism 1g, the first diaphragm portion 30A and the second diaphragm portion 30B are formed by the thicknesses of the first spacer 31A and the second spacer 31B. For example, the rotation mechanism 1g can change the sizes of the first aperture portion 30A and the second aperture portion 30B by changing the thicknesses of the first spacer 31A and the second spacer 31B in accordance with the intended use.

Since the rotation mechanism 1g forms the first aperture portion 30A and the second aperture portion 30B by the first spacer 31A and the second spacer 31B, the first member 2FARg is required to have only the flatness of the surface 2FARP, and the second member Only the flatness of the surface 2 FASP is required for 2FASg. Only the flatness of the surface 2FBPg is required for the second structure 2FBg to form the second diaphragm portion 30B. For this reason, the rotation mechanism 1g does not require management of the diameter tolerances of the first member 2FARg, the second member 2FASg, and the second structure 2FBg, and therefore has an advantage that the number of component accuracy management items can be further reduced. As a result, the yield is further improved.

As described above, the first to fifth embodiments have been described. However, the first to fifth embodiments are not limited to the above-described contents. In addition, the above-described constituent elements include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the above-described components can be appropriately combined. Furthermore, at least one of various omissions, substitutions, and changes of the components can be made without departing from the spirit of the first to fifth embodiments.

1, 1a, 1b, 1c, 1d, 1e Rotating mechanism 2, 2a, 2b, 2c, 2d, 2e Housing 2SI Through hole 2HA First hole 2HB Second hole 2FA, 2FBa, 2FAb, 2FAd, 2FAe First structure 2FB 2FBa, 2FBb, 2FBc, 2FBd, 2FBd Second structure 2FAP, 2FBP Surface 2FAS, 2FASb, 2FASd, 2FBS, 2FBBSa, 2FBBSc, 2FBSd, 2FBBSe First member 2FAR, 2FARd, 2FBR, 2FBRa, 2FBRb, 2FBRc, 2FBR 2FBRe Second member 2FRAS, 2FSAS, 2FYA, 2FYB Side part 2FBE, 2FBF Overhang part 2FBI Inner peripheral surface 2S, 2Sd Main body part 2SI Inner peripheral part 2SHd Overhang part 3 Electric motor 4 Shaft 4TA First end part 4TB Second end part 5A, 5Ab, 5Ac, Ad 1st rotation member 5B, 5Bb, 5Bc, 5Bd, 5Be 2nd rotation member 5BE, 5BEd Side part 5FA, 5FAd Overhang part 5WI Inner peripheral part 5BJ, 5BJe, 5BI, 5Bie Member 5APS, 5APR, 5BPS, 5BPR Surface 6A First support member 6B Second support member 7A, 7B, 7C Bearing 8 Preload member 9A, 9B Groove 10A First gas passage 10B Second gas passage 11A First opening 11B Second openings 12A, 12B, 14A, 14B Clearance 13A First 1 gap 13B, 13Bc, 13Bd 2nd gap 15A, 15B part (large gap part)
16, 17

Groove

18A, 18B part (small gap part)
50 Air supply device Zr Rotation center shaft

Claims

A housing;
A shaft inserted through a first hole and a second hole provided in the housing;
A bearing installed in the housing and rotatably supporting the shaft;
A projecting portion provided at a first end portion of the shaft and rotating together with the shaft; projecting to a radially outer side of the first hole and to a side portion of the housing; A first rotating member opposed to the portion with a first gap of a predetermined size;
The shaft is provided at the second end of the shaft, rotates together with the shaft, and projects to the outside in the radial direction of the second hole, and has a second gap of a predetermined size with the housing on the second end side. A second rotating member facing each other,
A first gas is supplied to the first gap by opening radially outward of the first hole of the housing, facing the first rotating member, and extending along a circumferential direction of the first hole. One opening,
The second opening of the housing is radially outward of the second hole, faces the second rotating member, extends along the circumferential direction of the second hole, and supplies gas to the second gap. 2 openings,
Including rotation mechanism.
The rotation mechanism according to claim 1, wherein the first rotation member is disposed above the second rotation member.
The said 1st clearance gap is larger than the dimension of the said 1st opening in the radial direction of the said shaft, The said 2nd clearance gap is larger than the dimension of the said 2nd opening in the radial direction of the said shaft. 2. The rotation mechanism according to 2.
The space between the first rotating body and the housing between the first hole and the first opening includes a portion smaller than the dimension of the first opening in the radial direction of the first hole, and the second The space between the second rotating body and the housing between the hole and the second opening includes a portion smaller than the dimension of the second opening in the radial direction of the first hole. 4. The rotation mechanism according to any one of items 3.
The rotation mechanism according to any one of claims 1 to 4, further comprising a groove along a circumferential direction of the first hole in a portion adjacent to the first gap of the housing.
The rotation mechanism according to any one of claims 1 to 5, further comprising a groove along a circumferential direction of the second hole in a portion adjacent to the second gap of the second rotation member.
The first opening is formed between two parts, extends in a direction orthogonal to the rotation center axis of the shaft, and has a gap smaller than that of the first opening. Gas is supplied,
The second opening is formed between two parts, extends in a direction perpendicular to the rotation center axis of the shaft, and has a gap smaller than that of the second opening. The rotation mechanism according to any one of claims 1 to 6, wherein gas is supplied.
The first spacer is provided between two parts forming the first throttle part, and the second spacer is provided between two parts forming the second throttle part. The rotating mechanism described.
A machine tool comprising the rotation mechanism according to any one of claims 1 to 8.
A semiconductor manufacturing apparatus comprising the rotation mechanism according to any one of claims 1 to 8.