JP2015121265A - Magnetic fluid bearing device and vacuum chamber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum chamber and a magnetic fluid bearing device capable of accepting a load in a superior manner even if a radial load accompanied with a deflection angle is applied under a relative spherical surface motion between an inner member and an outer member and capable of holding a clearance between each of the members.SOLUTION: The present invention relates to a magnetic fluid bearing device comprising an inner member 1 and an outer member 2 that is rotatably applied over the inner member 1 with their axial directions being aligned to each other. A plurality of rollers 5 are arranged between a spherical convex outer peripheral surface 3 of the inner member 1 and an inner peripheral surface 4 of the outer member 2 of spherical concave surface opposing against the spherical convex surface, the inner member 1 and the outer member 2 are constituted in such a manner that they can perform a relative spherical surface motion along the spherical convex surface and the spherical concave surface and there is provided a magnetic fluid seal for sealing a curved clearance curved to protrude outward and formed between the inner member 1 and the outer member 2.

Description

  The present invention relates to a magnetic fluid bearing device and a vacuum chamber.

  For example, there is known a magnetic fluid bearing that seals a gap formed between a relatively rotating inner member and an outer member with a magnetic fluid seal, which performs vacuum sealing of a rotating mechanism disposed inside the vacuum device. In general, the magnetic fluid seal has a plurality of annular protrusions arranged in parallel in the axial direction on the outer peripheral surface of the inner member, an annular pole piece arranged outside the annular protrusion, and a gap between them. It consists of intervening magnetic fluid.

  By the way, the magnetic fluid seal of the conventional magnetic fluid bearing is provided for the purpose of sealing the shaft supported by the radial bearing as disclosed in Patent Document 1 and the like.

  For this reason, a radial load with a declination cannot be accommodated.For example, if a large radial load with a declination is applied between the inner member and the outer member, an excessive load is applied to the radial bearing, and this load is received. Since it does not break, the clearance between the pole piece and the annular protrusion cannot be maintained. As a result, the magnetic fluid may disappear from between the pole piece and the annular protrusion, and the sealing performance may be deteriorated.

  In particular, as disclosed in Patent Document 2, for example, an atmospheric box that forms an atmospheric region isolated from the vacuum region is provided in the vacuum chamber so as to be linearly movable by a guide mechanism. Magnetic fluid bearings at connecting portions of the arms constituting the atmosphere arm in a vacuum apparatus in which the atmosphere box and the vacuum chamber are connected via an atmosphere arm having a hollow inside in order to introduce wiring and piping into the atmosphere box When this is used, the following problems occur.

  That is, in a vacuum device having a size of several meters, it is difficult to assemble the guide mechanism, the atmospheric arm, and the vacuum chamber in exactly parallel with each other, and when the vacuum chamber is decompressed, the arm and the vacuum chamber are deformed. . For this reason, when the atmospheric box or the atmospheric arm is moved due to these effects, a radial load with a declination is applied to the magnetic fluid bearing of each connecting portion, and the magnetic fluid seal may be damaged.

Japanese Utility Model Publication No. 7-38819 JP 2009-299176 A

  The present invention was made in view of the current situation as described above, and even when a radial load with a declination is applied, the inner member and the outer member can be relatively spherically moved to receive the load satisfactorily. It is an object of the present invention to provide a magnetic fluid bearing device and a vacuum chamber that can maintain a clearance between members.

  The gist of the present invention will be described with reference to the accompanying drawings.

  An inner member 1 and an outer member 2 that is rotatably fitted to the inner member 1 so as to be axially aligned. An outer peripheral surface 3 that is a spherical convex surface of the inner member 1 and a spherical concave surface that faces the spherical convex surface. A plurality of rolling elements 5 are disposed between the inner peripheral surface 4 of the outer member 2 and the inner member 1 and the outer member 2 are relatively spherical along the spherical convex surface and the spherical concave surface. A magnetic fluid bearing device comprising a magnetic fluid seal configured to be movable and sealing a curved gap that is convexly curved outwardly formed between the inner member 1 and the outer member 2. It is concerned.

  The magnetic fluid seal includes a plurality of annular protrusions 6 arranged in parallel in the axial direction on the outer peripheral surface 3 of the inner member 1 or the inner peripheral surface 4 of the outer member 2, and the inner peripheral surface of the outer member 2. 4 or a pole piece 7 provided on the outer peripheral surface 3 of the inner member 1 and facing the annular protrusion 6 with the curved gap interposed therebetween, and a magnet interposed between the pole piece 7 and the annular protrusion 6 Each of the opposed surface shapes of the annular protrusion 6 and the pole piece 7 is a spherical convex shape of the outer peripheral surface 3 of the inner member 1 on which the annular protrusion 6 and the pole piece 7 are respectively provided, and The magnetic fluid bearing device according to claim 1, wherein the outer peripheral member is set to have a shape that conforms to a spherical concave shape of the inner peripheral surface of the outer member.

  2. The apparatus according to claim 1, further comprising a relative movement amount limiting unit that limits a relative movement amount between the inner member 1 and the outer member 2 to a range in which the sealing by the magnetic fluid seal is not broken. 2. The magnetic fluid bearing device according to any one of 2 above.

  Further, a plurality of rolling element rows each including a plurality of rolling elements 5 arranged in the circumferential direction are arranged in parallel in the axial direction between the inner member 1 and the outer member 2, and the magnetic elements are arranged between the rolling element rows. The fluid hydrodynamic bearing device according to any one of claims 1 to 3, wherein a fluid seal is provided.

A vacuum chamber comprising an atmospheric chamber 10 moving in the vacuum chamber 9 and an atmospheric connecting arm 11 having a first connecting arm 12 and a second connecting arm 13;
The first connecting arm 12 and the side surface of the vacuum chamber 9 are connected by a first rotation connecting portion,
The first connecting arm 12 and the second connecting arm 13 are connected by a second rotation connecting portion,
The second connecting arm 13 and the atmospheric chamber 10 are connected by a third rotation connecting portion,
At least the second rotation connecting portion includes the magnetic fluid bearing device according to any one of claims 1 to 4, and relates to a vacuum chamber.

  Since the present invention is configured as described above, even when a radial load with a declination is applied, the inner member and the outer member can be relatively spherically moved to receive the load satisfactorily, and the clearance between each member The magnetic fluid bearing device and the vacuum chamber can be held.

It is a schematic explanatory side view of the atmospheric chamber and the atmospheric connecting arm in the vacuum chamber. It is a schematic explanatory plan view of the atmosphere chamber and the atmosphere connecting arm in the vacuum chamber. It is a schematic explanatory side view at the time of making the vacuum chamber into a vacuum state. It is an expansion outline explanatory sectional view of a present Example.

  An embodiment of the present invention which is considered to be suitable will be briefly described with reference to the drawings showing the operation of the present invention.

  When a radial load with a declination is applied between the inner member 1 and the outer member 2, the inner member 1 and the outer member 2 are relatively spherically moved via the rolling elements 5 to receive the load satisfactorily. And the clearance between the members is maintained.

  Factors that cause such a radial load with a declination include a deformation of the vacuum chamber and an error during assembly.

  For example, as shown in FIG. 1, when an atmospheric chamber 10 is formed in the vacuum chamber 9 for adsorbing the substrate and forming an atmospheric region isolated from the vacuum region, the atmospheric chamber 10 is externally provided. The air chamber 10 and the vacuum chamber 9 are connected via an air connecting arm 11 having a hollow inside in order to introduce wiring and piping. The atmospheric connecting arm 11 is configured by rotatably connecting a plurality of connecting arms in order to follow the movement of the atmospheric chamber 10 that is guided by a guide mechanism and moves horizontally (see FIG. 2). Here, when the vacuum chamber 9 is depressurized to be in a vacuum state, the wall portion of the vacuum chamber 9 bends inward as shown in FIG. A radial load with corners acts.

  At this time, if the present invention is applied to the rotation connecting portion A of the atmosphere connecting arm 11, even if a radial load with a declination acts on the rotation connecting portion A due to the bending of the vacuum chamber 9, FIG. , 4, the inner member 1 and the outer member 2 are relatively spherically moved along the spherical convex surface of the inner member 1 and the spherical concave surface of the outer member 2 so that the radial load with this declination is good. Therefore, for example, a curved gap between the annular protrusion 6 and the pole piece 7 constituting the magnetic fluid seal can be held, and the vacuum sealing performance due to the disappearance of the magnetic fluid 8 from the curved gap. Can be prevented. Further, it is possible to absorb a load caused by an external force such as deformation of the vacuum chamber 9, so that the performance of the seal portion can be maintained and the bearing life can be extended.

  In addition, even if a radial load with a declination is applied due to the effects of errors during assembly, the effects can be reduced, that is, the allowable value of the assembly adjustment range can be set large, and the assembly adjustment can be made easier. Become.

  Further, for example, when the relative movement amount of the inner member 1 and the outer member 2 is configured to include a relative movement amount limiting portion that limits the range of the sealing by the magnetic fluid seal, the sealing action is more reliably performed. Can be prevented.

  Specific embodiments of the present invention will be described with reference to the drawings.

  The present embodiment is a ferrofluid bearing device comprising an annular inner member 1 and an annular outer member 2 that is rotatably fitted to the inner member 1 in the axial direction. It is provided in the rotation connecting part A (second rotation connecting part) of the atmosphere connecting arm 11 for introducing the wiring to the atmosphere chamber 10 in the vacuum chamber 9 from the outside.

  1, 3, and 4, the rotation connecting portion 24 (first rotation connecting portion) between the atmospheric chamber 10 and the atmosphere connecting arm 11 and the rotation connecting portion 25 (first rotation connecting portion) between the vacuum chamber 9 and the atmosphere connecting arm 11 ( The third rotation connecting portion) employs a general magnetic fluid bearing, but the annular inner member 1 and a circle that is rotatably fitted to the inner member 1 so as to be axially aligned. A magnetic fluid bearing device including the annular outer member 2 may be employed.

  Specifically, in this embodiment, a plurality of rolling elements are provided between the outer peripheral surface 3 which is a spherical convex surface of the inner member 1 and the inner peripheral surface 4 of the outer member 2 which is a spherical concave surface corresponding to the spherical convex surface. 5, the inner member 1 and the outer member 2 are configured to be relatively spherically movable along the spherical convex surface and the spherical concave surface, and between the inner member 1 and the outer member 2. A magnetic fluid seal is provided to seal the curved gap convexly formed outward.

  1 and 2, the atmosphere connecting arm 11 is provided on the side surface of the vacuum chamber 9, but the atmosphere connecting arm 11 may be provided on the upper surface side or the lower surface side of the vacuum chamber 9.

  The magnetic fluid seal is provided on the outer peripheral surface 3 of the inner member 1 in the axial direction with a plurality of annular protrusions 6 and on the inner peripheral surface 4 of the outer member 2 with the curved gap interposed therebetween. The pole piece 7 is opposed to the annular protrusion 6 and the magnetic fluid 8 is interposed between the pole piece 7 and the annular protrusion 6. The annular protrusion 6 is formed by providing a groove on the outer peripheral surface 3 of the inner member 1. In FIG. 4, reference numeral 22 denotes a permanent magnet, and 23 denotes an O-ring. The outer member 2 of the present embodiment is formed of a divided body, and is integrated after the pole piece 7 with the O-ring 23 and the permanent magnet 22 are assembled in a separated state.

  And the opposing surface shape of the said annular protrusion 6 and the pole piece 7 is the spherical convex shape of the outer peripheral surface 3 of the said inner member 1 in which these annular protrusions 6 and the pole piece 7 are provided, respectively, and the inner periphery of the said outer member 2. It is set to a shape along the spherical concave shape of the surface 4.

  Specifically, the opposing surface shape of each annular protrusion 6 is a shape along the spherical convex shape of the outer peripheral surface 3 of the inner member 1, that is, the outer shape of the outer peripheral surface 3 forming the spherical convex surface as a whole of the inner member 1. The curved surface shape matches the above. The opposing surface shape of the pole piece 7 matches the shape of the spherical concave surface of the inner peripheral surface 4 of the outer member 2, that is, the outer shape of the inner peripheral surface 4 forming the spherical concave surface as a whole of the outer member 2. It has a curved shape.

  In this embodiment, the outer peripheral surface 3 that forms a spherical convex surface as the whole inner member 1 and the outer shape of the inner peripheral surface 4 that forms a spherical concave surface as a whole of the outer member 2 are opposed to the annular protrusion 6 and the pole piece 7. Although the surfaces are configured to match each other (substantially flush with each other), if the curved surface motion is not hindered, the opposed surfaces of the annular protrusion 6 and the pole piece 7 are somewhat protruding or immersing. Also good.

  Further, the annular protrusion 6 and the pole piece 7 may be provided at opposing positions, the annular protrusion 6 is provided on the outer peripheral surface 3 of the inner member 1, and the pole piece 7 is provided on the inner peripheral surface 4 of the outer member 2. Alternatively, the pole piece 7 may be provided on the outer peripheral surface 3 of the inner member 1 and the annular protrusion 6 may be provided on the inner peripheral surface 4 of the outer member 2. Further, the plurality of annular protrusions 6 provided in parallel are provided so as to be parallel to each other in FIG. 4, but may be provided so as to be perpendicular to the provided spherical convex surface or spherical concave surface.

  The atmosphere connecting arm 11 is configured by rotatably connecting a first connecting arm 12 on the lower side and a second connecting arm 13 on the upper side, and the first connecting arm 12 and the second connecting arm 13 are connected to each other. The present embodiment is provided in the rotation connecting portion A with the connecting arm 13.

  Specifically, the inner member 1 is connected to the first connecting arm 12, the outer member 2 is connected to the second connecting arm 13, and the hollow portion inside the first connecting arm 12 and the second connecting arm are connected. The hollow part inside 13 is configured to communicate in a sealed state. Therefore, the inside of each connecting arm 12 and 13 and the inside of the atmospheric chamber 10 are maintained at atmospheric pressure. In this embodiment, the first connecting arm 12 is connected to the inner member 1 with a screw or the like via a relative movement amount limiting body 15 described later. The second connecting arm 13 is connected to the mounting flange 14 of the outer member 2 with a screw or the like.

  In addition, this embodiment includes a relative movement amount limiting unit that limits the relative movement amount between the inner member 1 and the outer member 2 to a range in which the sealing by the magnetic fluid seal is not broken.

  Specifically, a base portion 17 having a center hole 16 communicating with the inside of the inner member 1 in a disk shape, and a cylindrical portion that rises from the periphery of the center hole 16 of the base portion 17 and fits to the inner peripheral surface 18 of the inner member 1. 19 are provided at both ends of the inner member 1 so that both end faces of the inner member 1 and the base portion 17 are in close contact with each other.

  At the outer peripheral end of the base portion 17 of the relative movement amount limiting body 15, there are provided opposing contact surfaces 21 that face the contact surfaces 20 provided at both ends of the outer member 2, respectively. When the contact surface 20 of the member 2 is in contact, further relative movement is prevented. In the present embodiment, stepped portions are provided at both ends of the outer peripheral surface 4 of the outer member 2, and the vertical surface of the stepped portion is set as the contact surface 20. Therefore, the relative movement amount can be appropriately set depending on the formation width of the stepped portion.

  Further, the rolling element 5 is configured to be held by a rolling element holding groove for holding the rolling element 5 provided on the inner peripheral surface 4 of the outer member 2 or the outer peripheral surface 3 of the inner member 1 or both. In this embodiment, an angular groove-shaped rolling element holding groove 26 is provided around the outer peripheral surface 3 of the inner member 1, and the rolling element 5 is held by the rolling element holding groove 26 and the inner peripheral surface 4 of the outer member 2. It is assumed to be configured. In addition, you may provide the spacer which hold | maintains the space | interval of the rolling elements 5 between each rolling element 5. FIG.

  Further, in this embodiment, a plurality of rolling element rows (the rolling element holding grooves 26) composed of a plurality of rolling elements 5 arranged in the circumferential direction between the outer member 2 and the inner member 1 are arranged in the axial direction (this embodiment). In the example, two are provided side by side, and the magnetic fluid seal is provided between the rolling element rows (the rolling element holding grooves 26).

  From the above, according to the present embodiment, even when a radial load with a declination is applied between the inner member 1 and the outer member 2, the gap between the annular protrusion 6 and the pole piece 7 constituting the magnetic fluid seal is applied. The curved gap can be held, and the deterioration of the vacuum sealing performance due to the disappearance of the magnetic fluid 8 from the curved gap can be prevented. Further, it is possible to absorb a load caused by an external force such as deformation of the vacuum chamber 9, so that the performance of the seal portion can be maintained and the bearing life can be extended.

  In addition, even if a radial load with a declination is applied due to the effects of errors during assembly, the effects can be reduced, i.e., the tolerance of the assembly adjustment range can be set large, and the assembly adjustment can be made easier. Become.

  Note that the present invention is not limited to this embodiment, and the specific configuration of each component can be designed as appropriate.

DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer member 3 Outer peripheral surface 4 Inner peripheral surface 5 Rolling element 6 Annular protrusion 7 Pole piece 8 Magnetic fluid 9 Vacuum chamber
10 Atmospheric chamber
11 Atmospheric articulated arms
12 First articulated arm
13 Second articulated arm

Claims (5)

  An outer member that is rotatably fitted with the inner member being axially aligned with the inner member, and an outer peripheral surface that is a spherical convex surface of the inner member and a spherical concave surface that faces the spherical convex surface. A plurality of rolling elements are disposed between the inner peripheral surface and the inner member and the outer member so as to be relatively spherically movable along the spherical convex surface and the spherical concave surface. A magnetic fluid bearing device comprising a magnetic fluid seal that seals a curved gap formed between the outer member and convex outward.   The magnetic fluid seal is formed on the outer peripheral surface of the inner member or the inner peripheral surface of the outer member, and a plurality of annular protrusions arranged in the axial direction thereof, A pole piece provided opposite the annular protrusion with the curved gap interposed therebetween, and a magnetic fluid interposed between the pole piece and the annular protrusion, and the annular protrusion and the pole piece Each of the opposing surface shapes is set to a shape along the spherical convex shape of the outer peripheral surface of the inner member and the spherical concave shape of the inner peripheral surface of the outer member provided with the annular protrusion and the pole piece, respectively. The ferrofluid bearing device according to claim 1.   The relative movement amount limiting unit for limiting a relative movement amount between the inner member and the outer member to a range in which the sealing by the magnetic fluid seal is not broken. The ferrofluid bearing device according to item 1.   A plurality of rolling element rows composed of a plurality of rolling elements arranged in the circumferential direction are arranged in parallel between the inner member and the outer member in the axial direction, and the magnetic fluid seal is provided between the rolling element rows. The magnetic fluid bearing device according to claim 1, wherein the magnetic fluid bearing device is a magnetic fluid bearing device. A vacuum chamber comprising an atmospheric chamber moving in the vacuum chamber, and an atmospheric connecting arm having a first connecting arm and a second connecting arm,
The first connecting arm and the side surface of the vacuum chamber are connected by a first rotation connecting portion,
The first connecting arm and the second connecting arm are connected by a second rotation connecting portion;
The second connecting arm and the atmosphere chamber are connected by a third rotation connecting portion,
The vacuum chamber characterized in that at least the second rotation connecting portion includes the magnetic fluid bearing device according to any one of claims 1 to 4.

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