Rotary joint

Abstract

To minimize a length in an axial direction without impairing a function of a rotary joint.SOLUTION: A rotary joint comprises: a cylindrical case body 2 at which one end of each of a plurality of outside channels 31, 32 through which a sealed fluid flows opens on the inner circumferential side; a shaft body 5 that is inserted into the case body so as to be rotatable relative to the case body and at which one end of each of a plurality of inside channels 61, 62 through which the sealed fluid flows opens on the outer circumferential side; a first bearing 8 that is provided on one side in an axial direction of the case body and rotatably supports the shaft body; a second bearing 9 that is provided on the other side in the axial direction of the case body and rotatably supports the shaft body 5; and a plurality of mechanical seal devices 7 that is aligned in the axial direction in an annular space A that is formed between an inner surface of the case body and an outer surface of the shaft body. An outer ring 9a of the second bearing is fixed to a cylindrical protrusion 9b that is formed inside the case body, and at least portions of the mechanical seal devices 7 overlap with the second bearing 9 as seen from a direction orthogonal to the axial direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a multi-port, multi-flow rotary joint. [Background technology]

[0002] For example, when configuring a rotary joint having multiple ports as in Patent Documents 1 and 2, the shaft and flange (casing) are centered by bearings arranged above and below the rotary joint. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-186804 [Patent Document 2] Japanese Patent Publication No. 2020-106052 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional rotary joints with multiple ports function by overlapping the components in the axial direction, and there is a need to make this axial length as small as possible.

[0005] The present invention has been made in view of the above points, and its object is to minimize the axial length of a rotary joint without impairing its function. [Means for solving the problem]

[0006] In order to achieve the above object, in the present invention, the arrangement of the bearings that support the shaft body is improved.

[0007] Specifically, in a first aspect of the present invention, there is provided a cylindrical case body in which one ends of a plurality of outer flow paths through which a sealed fluid flows are each open to an inner circumferential side; a shaft inserted into the case body so as to be rotatable relative to the case body, the shaft having a plurality of inner flow passages through which the sealed fluid flows, each of which has one end opening to an outer circumferential side; a first bearing provided on one axial side of the case body and rotatably supporting the shaft body; a second bearing provided on the other axial side of the case body and rotatably supporting the shaft body; a plurality of mechanical seal devices arranged side by side in the axial direction in an annular space formed between the inner surface of the case body and the outer surface of the shaft body, an outer ring of at least one of the first bearing and the second bearing is fixed to a cylindrical protrusion formed inside the case body, When viewed from a direction perpendicular to the axial direction, the mechanical seal devices are arranged so that at least a portion of one of the plurality of mechanical seal devices overlaps with at least one of the first bearing and the second bearing.

[0008] With the above configuration, the axial length of the shaft where the mechanical seal device and bearing overlap can be reduced compared to conventional cases where the mechanical seal device and bearing do not overlap when viewed perpendicular to the axial direction. Even in this case, the shaft is supported in the same way by misaligned bearings, so the functionality of the rotary joint is maintained.

[0009] In the second invention, in the first invention, The cylindrical protrusion is formed on a cover portion of the case body that covers the other side of the shaft body so as to extend in the axial direction.

[0010] According to the above configuration, since it is on the lid side, it is not necessary to arrange the inner flow path all the way to the end, and the tip of the shaft can be made thin so that the shaft can be easily supported by a bearing fixed to the cylindrical protrusion of the lid.

[0011] In the third invention, in the first invention, A rotor mounting portion that is fixed to a rotor is formed on one side of the shaft.

[0012] According to the above configuration, although the region is highly restricted on the base end side of the shaft where the rotor mounting portion is located, it is possible to similarly achieve compactness by ensuring a fluid passage within the shaft.

[0013] In a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, A flow path that connects one of the outer flow paths and one of the inner flow paths is formed in the annular space between the radial outer surface of the cylindrical protrusion and the radial inner surface of the mechanical seal device.

[0014] According to the above configuration, although the area is made compact in the axial direction, one port is still secured in this area.

[0015] In a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, When viewed from a direction perpendicular to the axial direction, the outer diameter of the portion of the shaft body that is rotatably supported by at least one of the first bearing and the second bearing and is arranged to overlap at least a portion of one of the multiple mechanical seal devices is smaller than the outer diameter of the shaft body in other portions.

[0016] According to the above configuration, the outer diameter of the shaft body can be reduced, thereby making it possible to reduce the size of the bearing, and the mechanical seal device and the bearing can be arranged in a position where they overlap when viewed from a direction perpendicular to the axial direction. [Effects of the Invention]

[0017] As described above, according to the present invention, by arranging the plurality of mechanical seal devices so that at least a portion of the one of the first bearing and the second bearing overlaps when viewed from a direction perpendicular to the axial direction, it is possible to minimize the axial length without impairing the function of the rotary joint. [Brief explanation of the drawings]

[0018] [Figure 1]FIG. 2 is an enlarged cross-sectional view of an upper portion of the rotary joint. [Figure 2] 1 is a cross-sectional view showing a rotary joint according to an embodiment of the present invention. [Figure 3] FIG. 2 is a view equivalent to FIG. 1 showing a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0020] Fig. 1 shows an upper portion of a rotary joint 1 according to a first embodiment of the present invention, and Fig. 2 shows the entire rotary joint 1. This rotary joint 1 includes a cylindrical case body 2 in which one end of each of a plurality of outer flow paths 31, 32 through which a sealed fluid flows is open to the inner periphery. This case body 2 constitutes, for example, a stationary member of a rotating device such as a CMP apparatus main body. Here, the sealed fluid is, for example, a gas such as pressurized air or an inert gas such as nitrogen, air for air blowing, or a vacuum, but is not limited to these.

[0021] A shaft 5 is inserted into the case 2 so as to be rotatable relative to the case 2. One end of each of a plurality of inner flow passages 61, 62 through which the sealed fluid flows is open to the outer periphery of the shaft 5. The shaft 5 is attached to, for example, a turntable of a CMP device.

[0022] In this embodiment, the axial direction is defined as the direction along the center line of the shaft body 5 and the direction parallel to it. For convenience, the up and down directions in the axial direction of the shaft body 5 are defined as up and down, but the axial direction may also be horizontal. In some cases, the shaft body 5 may be fixed to the device, and the case body 2 may rotate.

[0023] The case body 2 is made of, for example, an aluminum alloy and has a lower flange 21, a plurality of (three in this embodiment) flow path flanges 22, and an upper flange 23, which are stacked one on top of the other. The lower flange 21, flow path flange 22, and upper flange 23 are all annular, and are connected and fixed by a plurality of bolts 25 extending vertically. With this configuration, the case body 2 is hollow and cylindrical.

[0024] An O-ring 26 is provided between adjacent flanges to seal the sealed fluid. The flow path flange 22 and the upper flange 23 have annular protrusions 22a, 23a that protrude radially inward, respectively. A first outer flow path 31, through which the sealed fluid flows, is formed to extend radially through each of the protrusions 22a, 23a. A second outer flow path 32, through which the sealed fluid flows, is formed to extend radially through the portions of each of the flow path flanges 22 and the upper flange 23 excluding the protrusions 22a, 23a.

[0025] The first outer flow passages 31 and the second outer flow passages 32 are respectively open on the inner peripheral side and the outer peripheral side of the corresponding flow passage flange 22 and the upper flange 23. The openings on the outer peripheral side of each flow passage flange 22 and the upper flange 23 serve as pipe connection ports 22c and 23c to which corresponding pipes of the fixed-side member are connected. By stacking a plurality of flow passage flanges 22, a plurality of first outer flow passages 31 and second outer flow passages 32 through which the sealed fluid flows are formed in the case body 2 at intervals in the vertical direction along the axial direction.

[0026] The shaft body 5 is made of, for example, stainless steel, and is disposed on the inner periphery of the fixed-side case body 2 so as to be rotatable relative to the case body 2 .

[0027] In this embodiment, a small diameter portion 5a having a smaller outer diameter than the outer peripheral portion between the top and bottom is formed at the upper end of the shaft body 5. Meanwhile, a large diameter portion 5b having a larger outer diameter than the outer peripheral portion between the top and bottom is formed at the lower end of the shaft body 5, and a rotor mounting portion 5c having an even larger diameter is formed continuous with the large diameter portion 5b.

[0028] A first bearing 8 that rotatably supports the shaft body 5 is provided on one axial side (lower side) of the case body 2, and a second bearing 9 that rotatably supports the shaft body 5 is provided on the other axial side (upper side) of the case body 2.

[0029] A first bearing 8 such as a ball bearing is provided between the outer periphery of the large diameter portion 5b of the shaft 5 and the inner periphery of the lower flange 21. Similarly, a second bearing 9 such as a ball bearing is provided between the outer periphery of the small diameter portion 5a of the shaft 5 and the inner periphery of the cylindrical protrusion 9b of the upper flange 23, as will be described in detail later.

[0030] A plurality of (eight in total in this embodiment) flow passage holes 61a, 62a (four of each in this embodiment) extending vertically are formed inside the shaft 5, with the rotor mounting portion 5c side open. The upper end of each flow passage hole 61a, 62a communicates with the corresponding opening on the outer circumferential surface of the shaft 5. In this embodiment, only the flow passage hole 61a extending to the upper end of the shaft 5 is formed to penetrate all the way to the shoulder portion of the shaft 5.

[0031] As a result, each flow path hole 61a in the shaft body 5 constitutes a first inner flow path 61 through which the sealed fluid flows, and each flow path hole 62a in the shaft body 5 constitutes a second inner flow path 62 through which the sealed fluid flows. The upper ends of the first inner flow path 61 and the second inner flow path 62 open at positions offset from each other in the axial direction of the shaft body 5.

[0032] An annular space A is formed between the inner surface of the case body 2 and the outer surface of the shaft body 5. In this annular space A, a plurality of (four in this embodiment) mechanical seal devices 7 are arranged side by side in the axial direction.

[0033] The mechanical seal device 7 has a rotating side seal ring 72 fixed to the shaft body 5 so as to rotate integrally, a first case side seal ring 73 and a second case side seal ring 74 fixed to the case body 2, a first coil spring 75 and a second coil spring 76.

[0034] Specifically, an annular rotating-side seal ring 72 is fixed to the shaft 5 by bolts 72c at the opening position of the second inner flow passage 62 corresponding to the second outer flow passage 32 so as to rotate integrally with the shaft 5. The upper end of the second inner flow passage 62 opens into this rotating-side seal ring 72. The rotating-side seal ring 72 is made of, for example, a stainless steel base material with sliding materials that have excellent wear resistance and sealing performance arranged on both end faces. Specifically, first and second seal surfaces 72a, 72b, which are annularly coated with ceramic, are formed on the top and bottom of the rotating-side seal ring 72. A stationary O-ring 78 is provided between the inner periphery of the rotating-side seal ring 72 and the outer periphery of the shaft 5.

[0035] The first and second case-side seal rings 73, 74 are made of annular members and are respectively arranged above and below the rotating-side seal ring 72. The first and second case-side seal rings 73, 74 are prevented from rotating by abutting against anti-rotation pins 27 protruding from the protrusions 22a, 23a of the flow path flange 22 and the upper flange 23, and therefore function as stationary-side seal rings.

[0036] The lower surface of the first case side sealing ring 73 forms a first sealing surface 73a that comes into sliding contact with the first sealing surface 72a of the rotating side sealing ring 72, and the upper surface of the second case side sealing ring 74 forms a second sealing surface 74a that comes into sliding contact with the second sealing surface 72b of the rotating side sealing ring 72.

[0037] The first coil spring 75 is inserted in a compressed state into the insertion holes 22b, 23b formed in the protruding portions 22a, 23a of the flow path flange 22 and the upper flange 23, and one end side abuts against the first case side seal ring 73, pressing against the first case side seal ring 73. This maintains an appropriate axial pressing force between the two seal surfaces 72a, 73a.

[0038] Similarly, the second coil spring 76 is inserted in a compressed state into the insertion hole 22b formed in the protruding portion 22a of each flow path flange 22, with one end thereof abutting against the second case side seal ring 74 and pressing against the second case side seal ring 74. This maintains an appropriate axial pressing force between the two seal surfaces 72b, 74a.

[0039] Dynamic O-rings 79 are also provided between the outer peripheral surfaces of the first and second case-side seal rings 73, 74 and the inner peripheral surfaces of the protrusions 22a, 23a.

[0040] The axial pressing force of these seal surfaces may be achieved by a biasing means other than a coil spring.

[0041] By configuring it in this manner, when the shaft body 5 rotates relative to the case body 2, a sealing function is exerted to prevent leakage of the sealed fluid between the first seal surfaces 72a, 73a and the second seal surfaces 72b, 74a.

[0042] In the mechanical seal devices 7 that are adjacent to each other vertically in the axial direction, a cylindrical first gap flow path 41a, through which the sealed fluid can flow, is formed between the inner surface of the first case side sealing ring 73 of the lower mechanical seal device 7 and the inner surface of the second case side sealing ring 74 of the upper mechanical seal device 7, and the outer surface of the shaft body 5, and a first annular flow path 41b, through which the sealed fluid can flow, is formed between the upper surface of the first case side sealing ring 73 and the lower surface of the second case side sealing ring 74, so as to communicate with this first gap flow path 41a.

[0043] The first annular flow path 41b communicates with the first outer flow path 31 located radially outward of it. Each of the first gap flow paths 41a communicates with an opening of the first inner flow path 61 formed in the shaft body 5 at that position, and as a result, the first inner flow path 61 and the first outer flow path 31 communicate with each other, forming a first fluid passage 11.

[0044] Meanwhile, a cylindrical second gap flow passage 42a through which the sealed fluid flows is formed between each of the first and second case-side seal rings 73, 74 and the outer periphery of the rotating-side seal ring 72. This second gap flow passage 42a communicates with the second outer flow passage 32 located radially outward. Each second gap flow passage 42a communicates with the opening of the second inner flow passage 62 formed in the shaft 5 at that position, and as a result, the second inner flow passage 62 and the second outer flow passage 32 communicate with each other, forming a second fluid passage 12.

[0045] With this configuration, the rotary joint 1 of this embodiment is a multi-passage rotary joint.

[0046] A feature of this embodiment is that a cylindrical protrusion 9b is formed to extend in the axial direction on an upper flange 23 serving as a lid that covers the other side of the shaft 5 in the case body 2. An outer ring 9a of the upper second bearing 9 is fixed to the cylindrical protrusion 9b formed inside this case body 2. When viewed from a direction perpendicular to the axial direction, the second bearing 9 is arranged to overlap with a first case-side seal ring 73 that is part of one of the uppermost mechanical seal devices 7. In this embodiment, the second bearing 9 can be made smaller by reducing the outer diameter of the small-diameter portion 5a of the shaft 5, and the mechanical seal device 7 and the second bearing 9 can be arranged to overlap when viewed from a direction perpendicular to the axial direction.

[0047] In this embodiment, a flow path that connects the first outer flow path 31 and one of the first inner flow paths 61 is formed between the radial outer surface of the cylindrical protrusion 9b and the radial inner surface of the mechanical seal device 7 in the annular space A. In this way, one port is secured in an area that is compact in the axial direction.

[0048] 3 shows a rotary joint 101 of a comparative example, which has the same configuration as rotary joint 1 of the above embodiment except for the arrangement of second bearing 109. In this rotary joint 101, outer ring 109a of second bearing 109 is fixed to inner surface 109b of a recess formed in upper flange 123.

[0049] The small diameter portion 105a of the shaft 105 of this comparative example has a larger outer diameter than the small diameter portion 5a of the above embodiment. In this comparative example, when viewed from a direction perpendicular to the axial direction, the first case side seal ring 173 of the uppermost mechanical seal device 107 and the second bearing 109 are not arranged to overlap.

[0050] Therefore, the length H2 from the shoulder of the shaft body 105 to the upper surface of the upper flange 123 is longer than the length H1 from the shoulder of the shaft body 5 to the upper surface of the upper flange 23 in the above embodiment (H2>H1).

[0051] Therefore, compared to the comparative example in which the mechanical seal device 107 and the second bearing 109 do not overlap when viewed from a direction perpendicular to the axial direction, the axial length of the overlapping portion of the shaft 5 is reduced. Even with this configuration, the second bearing 9 firmly supports the shaft 5 in this embodiment, so the functionality of the rotary joint 1 is maintained.

[0052] Therefore, in the rotary joint of this embodiment, when viewed from a direction perpendicular to the axial direction, a portion of the upper end mechanical seal device 7 and the second bearing 9 are arranged to overlap, thereby making it possible to minimize the axial length without impairing the function of the rotary joint 1.

[0053] (Other embodiments) The present invention may be configured as follows in relation to the above embodiment.

[0054] That is, in the above embodiment, the cylindrical protrusion 9b is provided on the cover side, so that the tip of the shaft 5 is made thin and can be easily supported by the second bearing 9 fixed to the cylindrical protrusion 9b. However, the lower first bearing 8 side may be provided so as to overlap with the mechanical seal device 7 when viewed from a direction perpendicular to the axial direction. In this case, since the rotor mounting portion 5c that is fixed to the rotor is formed on the underside of the shaft 5, the cross-sectional area of ​​the large diameter portion 5b is reduced, which is a disadvantage in terms of installation space, but this can be realized by ensuring the inner flow paths 61, 62 inside the shaft 5.

[0055] It should be noted that the above-described embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses. [Explanation of symbols]

[0056] 1 rotary joint 2 Case body 5-axis body 5a Small diameter section 5b Large diameter part 5c Rotating body mounting part 7 Mechanical seal device 8 No. 1 bearing 9 Second bearing 9a outer ring 9b Cylindrical protrusion 11 1st fluid passage 12 Second fluid passage 21 Lower flange 22 Flow path flange 23 Upper flange (lid) 22a,23a protrusion 22b, 23b Insertion holes 22c, 23c Piping connection port 25 volts 26 O-ring 27 Anti-rotation pin 31 First outer channel 32 Second outer channel 41a First gap flow path 41b First annular flow path 42a Second gap flow path 61 First inner flow passage 61a Flow path hole 62 Second inner flow passage 62a Flow path hole 72 Rotating side seal ring 72a First sealing surface 72b Second sealing surface 73 First case side seal ring (stationary side seal ring) 73a First sealing surface 74 Second case side seal ring (stationary side seal ring) 74a Second sealing surface 75 First coil spring 76 Second coil spring 78 Stationary O-ring 79 Sports O-ring

Claims

1. a cylindrical case body (2) in which one ends of a plurality of outer flow paths (31, 32) through which a sealed fluid flows are each open to an inner peripheral side; a shaft (5) inserted into the case body (2) so as to be rotatable relative to the case body (2), and having a plurality of inner flow paths (61, 62) through which the sealed fluid flows, each of which has one end opening to an outer circumferential side; a first bearing (8) provided on one axial side of the case body (2) and rotatably supporting the shaft body (5); a second bearing (9) provided on the other axial side of the case body (2) and rotatably supporting the shaft body (5); a plurality of mechanical seal devices (7) arranged side by side in the axial direction in an annular space (A) formed between the inner surface of the case body (2) and the outer surface of the shaft body (5); an outer ring (9a) of at least one of the first bearing (8) and the second bearing (9) is fixed to a cylindrical protrusion (9b) formed inside the case body (2); When viewed from a direction perpendicular to the axial direction, at least a part of one of the plurality of mechanical seal devices (7) is arranged to overlap with at least one of the first bearing (8) and the second bearing (9). A rotary joint (1) characterized in that

2. The cylindrical protrusion (9b) is formed so as to extend in the axial direction on a cover (23) that covers the other side of the shaft body (5) in the case body (2). A rotary joint (1) according to claim 1 .

3. A rotating body mounting portion (5c) that is fixed to a rotating body is formed on one side of the shaft body (5). A rotary joint (1) according to claim 1 .

4. In the annular space (A), a flow path is formed between a radial outer surface of the cylindrical protrusion (9b) and a radial inner surface of the mechanical seal device (7), which allows communication between one of the outer flow paths (31, 32) and one of the inner flow paths (61, 62). A rotary joint (1) according to any one of claims 1 to 3.

5. When viewed from a direction perpendicular to the axial direction, the outer diameter of a portion (5a) of the shaft body (5) that is rotatably supported by at least one of the first bearing (8) and the second bearing (9), which is arranged so as to overlap at least a part of one of the plurality of mechanical seal devices (7), is smaller than the outer diameter of the shaft body (5) in other portions. A rotary joint (1) according to any one of claims 1 to 3.

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