Rotary joint

Abstract

To inhibit harmful effect of a lubricant on a seal end surface 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 and rotatably supports the shaft body; a second bearing 9 that is provided on the other side in the axial direction 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. A lubricant O is applied to an entire part or a part of seal surfaces 72a, 72b, 73a, 74a of the respective mechanical seal devices 7. Case side recessed grooves 28 which may store the lubricant scattered by centrifugal force are formed on inner surfaces 22d, 23d, which face the annular space, of the case body.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, as in Patent Documents 1 and 2, rotary joints with multiple ports seal and transfer gas to the device without using an externally supplied fluid such as water, so a lubricant may be applied to the seal end surface to prevent wear on the seal end surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-278424 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-321827 Summary of the Invention [Problem to be solved by the invention]

[0004] This lubricant may fly off the seal end face due to centrifugal force, and the lubricant adhering to the inner cylindrical surface of the flow path flange may flow out together with the supply gas, potentially affecting the device.

[0005] Furthermore, the scattered lubricant may also enter the bearing on the lower side of the rotary joint and mix with the grease inside the bearing, hindering the lubrication of the bearing and causing the bearing to seize.

[0006] The present invention has been made in view of the above points, and an object of the present invention is to suppress the adverse effects of the lubricant on the seal end face. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention is made so that lubricant can be temporarily stored.

[0008] 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, A lubricant is applied to all or part of the seal end surface of the mechanical seal device, A case-side recessed groove capable of storing the lubricant scattered by centrifugal force is formed on the inner surface of the case body facing the annular space.

[0009] With the above configuration, the lubricant applied to the seal end surface of the mechanical seal device is scattered by centrifugal force toward the inner surface of the case body facing the annular space, but because the case-side groove is formed on this inner surface, the lubricant is retained inside the case-side groove and is prevented from being released to the outside from the case body, which results in reducing the amount of lubricant flowing into the first bearing or the second bearing.

[0010] In the second invention, in the first invention, The case-side groove is formed in a plurality of stages in the axial direction for each of the plurality of mechanical seal devices on the inner surface of the case body that faces the annular space.

[0011] According to the above-mentioned configuration, by providing a plurality of stages of case-side grooves for each mechanical seal, lubricant scattered from the seal end face is reliably stored.

[0012] In a third aspect of the present invention, in the first or second aspect of the present invention, At least one end of the shaft body on one axial side and the other axial side is formed with a shaft-side groove that stores the lubricant that has flowed out and prevents it from flowing into the first bearing or the second bearing.

[0013] According to the above configuration, lubricant that flows out from the seal end face and attempts to flow toward the bearing side is stored in the shaft-side groove, so that it is reliably prevented from flowing into the bearing and adversely affecting the bearing.

[0014] In a fourth aspect of the present invention, in the third aspect of the present invention, The total volume of the lubricant that can be stored in the case-side groove and the shaft-side groove is greater than the total amount of lubricant applied to all of the seal end faces of the plurality of mechanical seal devices.

[0015] According to the above configuration, the total volume of the recessed grooves is made larger than the total amount of lubricant applied to the seal end surface, so that the lubricant can be stored reliably. [Effects of the Invention]

[0016] As described above, according to the present invention, a case-side groove capable of storing lubricant scattered by centrifugal force is formed on the inner surface of the case body facing the annular space, thereby suppressing the adverse effects of the lubricant on the seal end surface. [Brief explanation of the drawings]

[0017] [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. 10 is a view equivalent to FIG. 1, showing a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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 .

[0026] 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.

[0027] 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.

[0028] 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 bearing recess 9b of the upper flange 23.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] The axial pressing force of these seal end faces may be achieved by a biasing means other than a coil spring.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] With this configuration, the rotary joint 1 of this embodiment is a multi-passage rotary joint.

[0045] In this embodiment, a lubricant O is applied to the seal surfaces 73a and 74a of the mechanical seal device 7. The type of lubricant O may be oil or grease, but is not particularly limited.

[0046] The lubricant O may be applied to the seal surfaces 72a and 72b instead of the seal surfaces 73a and 74a, or may be applied to all of the seal surfaces 72a, 72b, 73a, and 74a. Furthermore, the seal surfaces 73a and 74a may be provided with a circumferential groove or multiple depressions so that the lubricant O can be easily retained between the seal surfaces 72a and 73a and between the seal surfaces 72b and 74a.

[0047] As a feature of this embodiment, a case-side recessed groove 28 capable of storing lubricant O scattered by centrifugal force is formed on the inner surface of the case body 2 facing the annular space A.

[0048] Specifically, eight stages of the case-side grooves 28 are formed on the inner surfaces 22d, 23d of the flow path flange 22 and the upper flange 23, respectively, that face the annular space A. The case-side grooves 28 are continuous around the entire circumference, but in some cases may not be continuous in the circumferential direction. The case-side grooves 28 may have more or fewer stages than eight, as long as each flange 22, 23 can secure a capacity greater than the total amount of lubricant O applied to each seal surface 72a, 72b, 73a, 74a.

[0049] A shaft-side groove 5d is formed on the upper surface of the large-diameter portion 5b on the lower end side of the shaft body 5 to collect the leaked lubricant O and prevent it from flowing into the first bearing 8. The shaft-side groove 5d is an annular groove recessed into the upper surface of the large-diameter portion 5b.

[0050] Looking at the rotary joint 1 as a whole, the total volume of lubricant O that can be stored in the case side groove 28 and the shaft side groove 5d needs to be greater than the total amount of lubricant O applied to all seal surfaces 72a, 72b, 73a, 74a of the multiple mechanical seal devices 7.

[0051] Therefore, in the rotary joint 1 according to this embodiment, the case body 2 has inner surfaces 22d, 23d facing the annular space A formed with case-side grooves 28 capable of storing lubricant O scattered by centrifugal force, thereby suppressing the adverse effects of the lubricant O between the seal surfaces 72a, 73a and between the seal surfaces 72b, 74a.

[0052] In addition, a shaft-side groove 5d is formed on the upper surface of the large-diameter portion 5b at the lower end of the shaft body 5 to collect dripping lubricant O and prevent it from flowing into the first bearing 8.Therefore, lubricant O that flows out from between the seal surfaces 72a, 73a and between 72b, 74a and attempts to flow toward the first bearing 8 is collected in the shaft-side groove 5d, thereby effectively preventing the lubricant O from flowing into the first bearing 8 and causing adverse effects on the first bearing 8.

[0053] -Variations- Figure 3 shows a rotary joint 101 according to a modified embodiment of the present invention, which differs from the above-described embodiment in that it has a different number of case-side grooves 28. In this modified embodiment, the same parts as those in Figures 1 and 2 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0054] In this modification, unlike the above embodiment, only two upper and lower case-side grooves 28 are formed on inner surfaces 22d, 23d of the flow path flange 22 and the upper flange 23 that face the annular space A.

[0055] In this modified example, it is sufficient that the two-stage upper and lower case side grooves 28 in each flange 22, 23 can secure a capacity greater than the total amount of lubricant O applied to each sealing surface 72a, 72b, 73a, 74a, and in some cases the case side grooves 28 may only have one stage.

[0056] (Other embodiments) The present invention may be configured as follows in relation to the above embodiment.

[0057] That is, in the above embodiment, the axial direction of the shaft body 5 was vertical, so the shaft-side groove 5d was provided on the upper surface of the large diameter portion 5b, but if, for example, the axial direction of the shaft body 5 is horizontal, the shaft-side groove may be provided not only on the large diameter portion 5b side but also on the small diameter portion 5a side.

[0058] 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]

[0059] 1 rotary joint 2 Case body 5-axis body 5a Small diameter section 5b Large diameter part 5c Rotating body mounting part 5d Shaft side groove 7 Mechanical seal device 8 No. 1 bearing 9 Second bearing 9a outer ring 9b Bearing recess 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 22d, 23d inner surface 25 volts 26 O-ring 27 Anti-rotation pin 28 Case side groove 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 seal surface (seal end surface) 72b Second seal surface (seal end surface) 73 First case side seal ring (stationary side seal ring) 73a First seal surface (seal end surface) 74 Second case side seal ring (stationary side seal ring) 74a Second seal surface (seal end 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); A lubricant (O) is applied to all or part of the seal end surfaces (72a, 72b, 73a, 74a) of the mechanical seal device (7), The inner surfaces (22d, 23d) of the case body (2) facing the annular space (A) are formed with case-side grooves (28) capable of storing the lubricant (O) scattered by centrifugal force. A rotary joint (1) characterized in that

2. The case-side grooves (28) are formed in a plurality of stages in the axial direction for each of the plurality of mechanical seal devices (7) on the inner surfaces (22d, 23d) of the case body (2) facing the annular space (A). A rotary joint (1) according to claim 1 .

3. At least one end of the shaft body (5) on one axial side and the other axial side is formed with a shaft-side recessed groove (5d) for storing the lubricant (O) that has flowed out and preventing it from flowing into the first bearing (8) or the second bearing (9). A rotary joint (1) according to claim 1 or 2.

4. The total capacity of the lubricant (O) that can be stored in the case-side groove (28) and the shaft-side groove (5d) is greater than the total amount of the lubricant (O) applied to all the seal end faces (72a, 72b, 73a, 74a) of the plurality of mechanical seal devices (7). A rotary joint (1) according to claim 3.

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