JP6823467B2 - Rotary joint - Google Patents

Description

The present invention relates to a rotary joint.

A rotary joint is known as a joint provided between a pipe of a device on one side and a rotating portion of the device on the other side and used for a connecting portion for supplying a fluid from the pipe to the rotating portion.
The rotary joint shown in FIG. 3 is mechanically provided between the joint main body 90, the rotary shaft 91 rotatably held by the joint main body 90, and the joint main body 90 and the rotary shaft 91 to prevent leakage of the fluid. It includes a seal 92 (see, for example, Patent Document 1).

The joint body 90 has a block portion 90a in which a first flow path 93 is formed and a cylindrical portion 90b, and a pipe (not shown) of a device on one side is connected to the first flow path 93. .. A second flow path 94 is formed inside the rotating shaft 91, and a rotating portion (not shown) of the device on the other side is connected to the end portion 91a. The rotating shaft 91 is made of a cylinder made of stainless steel or resin, is connected to the cylindrical portion 90b via a rolling bearing 95, and is rotatable with respect to the joint body 90.

The mechanical seal 92 has a static sealing ring 96 and a rotating sealing ring 97 provided between the joint body 90 (block portion 90a) and the rotating shaft 91. The static sealing ring 96 is in a sealed state with the block portion 90a, and is attached to the block portion 90a so as to be non-rotatable and movable in the axial direction. The rotary sealing ring 97 is in a state of being sealed from the rotary shaft 91, and is attached to the rotary shaft 91 so as to be integrally rotatable via a pin 101.

Then, the spring member 99 provided between the block portion 90a and the static sealing ring 96 pushes the static sealing ring 96 axially toward the rotary sealing ring 97, so that the sealing surfaces 96a of both sealing rings 96 and 97 , 97a are in close contact with each other. The mechanical seal 92 prevents the fluid 98 flowing from the first flow path 93 to the second flow path 94 from leaking to the outside.

Japanese Unexamined Patent Publication No. 2003-2003444

In the rotary joint, since the pin 101 is used as the detent structure of the rotary sealing ring 97 with respect to the rotary shaft 91, the following problems occur. That is, when the rotary sealing ring 97 rotates together with the rotary shaft 91, it receives a reaction force from the pin 101 (a force acting in a direction that suppresses the relative rotation with respect to the rotary shaft 91), so that the rotation stopper structure is used for a long period of time. , The notch 97b of the rotary sealing ring 97 with which the pin 101 is engaged may be deformed, and the rotary sealing ring 97 may be damaged.

Therefore, as the detent structure, it is conceivable to use a key member having a larger contact area with the rotating shaft 91 than the pin 101. However, in this case, since a key groove with which the key member engages is formed on the inner peripheral portion of the rotary sealing ring 97, a part of the radial thickness (inner peripheral portion) of the rotary sealing ring 97 is a rotating shaft. When rotating with 91, the reaction force from the key member is concentrated and received. Therefore, if the detent structure using the key member is used for a long period of time, there is still a possibility that the rotary sealing ring 97 will be damaged.

The present invention has been made in view of such circumstances, and a rotary capable of suppressing damage to the rotary sealing ring due to a structure for preventing the rotary sealing ring of the mechanical seal from rotating with respect to the rotating shaft. The purpose is to provide a joint.

The rotary joint of the present invention is held rotatably on the inner peripheral side of a block portion in which the first flow path is formed, a joint body having a cylindrical portion extending axially from the block portion, and the cylindrical portion. A rotating shaft having a second flow path formed inside, a static sealing ring attached to the block portion and having a sealing surface formed therein, and a static sealing ring arranged on the outer periphery of the rotating shaft. A mechanical seal having a rotary sealing ring having a sealing surface formed in sliding contact with the sealing surface to prevent fluid flowing between the first flow path and the second flow path from leaking to the outside, and the rotary sealing ring. The rotation prevention structure includes a rotation prevention structure for preventing rotation with respect to the rotation shaft, and the rotation prevention structure is such that the end surface on one side in the axial direction faces the back surface on the opposite side to the sealing surface of the rotation sealing ring. In a drive ring arranged on the outer periphery of the shaft, a recess formed in one surface of the back surface of the rotary sealing ring and the end surface of the drive ring over the entire radial thickness, and in the other surface. A convex portion formed over the entire thickness in the radial direction and engaged with the concave portion, a first key groove formed on the inner circumference of the drive ring, and an outer circumference of the rotating shaft facing the first key groove. It is composed of a second key groove formed in the above and a key member fitted in the first and second key grooves.

According to the present invention, the detent structure for detenting the rotary seal ring of the mechanical seal with respect to the rotary shaft is driven with respect to the rotary shaft by the key members fitted to each other and the first and second key grooves. The ring can be detented. Then, the concave portion and the convex portion engaged with each other can prevent the rotary sealing ring from rotating with respect to the drive ring. As a result, the rotary sealing ring can be prevented from rotating with respect to the rotary shaft via the drive ring.

Since the concave portion and the convex portion are formed over the entire radial thickness, the reaction force acting on the rotary sealing ring from the key member via the drive ring, the concave portion and the convex portion is applied in the radial direction of the rotary sealing ring. Can be received over the entire thickness of. As a result, unlike the conventional case, a part of the radial thickness of the rotary sealing ring does not receive the reaction force from the key member in a concentrated manner, so that the rotation sealing ring is effectively damaged due to the detent structure. Can be suppressed.

In the rotary joint, the drive ring preferably has an annular flange portion that projects outward in the radial direction. In this case, since the outer diameter of the drive ring is increased by the flange portion, the moment (angular momentum) around the axis of the drive ring is increased. As a result, the posture of the rotational movement of the rotary sealing ring that rotates integrally with the drive ring is stabilized, so that the vibration (axial runout) of the rotary sealing ring is suppressed. As a result, the durability of the rotary sealing ring can be improved.

According to the present invention, it is possible to prevent the rotary sealing ring from being damaged due to the structure that prevents the rotary sealing ring of the mechanical seal from rotating with respect to the rotating shaft.

It is a vertical sectional view which shows the rotary joint which concerns on one Embodiment of this invention. It is a vertical sectional view which enlarged the main part of FIG. It is a vertical sectional view which shows the conventional rotary joint.

[overall structure]
Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a vertical sectional view showing a rotary joint according to an embodiment of the present invention. The rotary joint 1 is a 1-port joint using a mechanical seal 30, and is used, for example, as a rotating portion in a CMP (Chemical Mechanical Polishing) apparatus included in a semiconductor manufacturing system.

Specifically, the rotary joint 1 is provided between the pipe 2 of the equipment on one side (fixed side equipment) and the rotating side member 3 of the equipment on the other side, and from this pipe 2 to the rotating side member 3. It is used for the connection part that supplies the fluid 4. The rotating side member 3 rotates with respect to the fixed side device. An example of the fluid 4 is ultrapure water.

The rotary joint 1 is provided between the joint body 20 connected to the pipe 2 of the fixed side device, the rotating shaft 10 connected to the rotating side member 3, and the joint body 20 and the rotating shaft 10, and the fluid is provided. It is provided with a mechanical seal 30 for preventing leakage of 4. The rotating shaft 10 is rotatably connected to the joint body 20.

The joint body 20 has a divided structure, has a block portion 22 as one divided body, and has a cylindrical portion 23 as the other divided body. A first flow path 21 through which the fluid 4 flows is formed inside the block portion 22, and a pipe 2 of the fixed-side device is connected to the first flow path 21. The cylindrical portion 23 is a member extending in the axial direction from the block portion 22.

Further, inside the block portion 22, a hole 24 continuous with the first flow path 21 is formed. The hole 24 is formed as a hole centered on the center line C of the joint body 20. The center line C of the joint body 20 becomes the center line of the rotary joint 1, and the rotating shaft 10 rotates around the center line C.

The block portion 22 has a large diameter portion 22a and a small diameter portion 22b, and a stepped portion 22c is formed on the radial outer edge portion of the block portion 22. The cylindrical portion 23 is fitted on the small diameter portion 22b and is in axial contact with the large diameter portion 22a. The center line of the cylindrical portion 23 coincides with the center line C of the joint body 20. An O-ring 5 is interposed between the small diameter portion 22b and the end portion of the cylindrical portion 23 to prevent the cooling medium for the mechanical seal 30 (cooling water 50 described later) from leaking to the outside of the joint body 20. prevent.

The rotating shaft 10 is made of stainless steel or resin, and a second flow path 12 through which the fluid 4 flows is formed inside the rotating shaft 10. Then, the rotating side member 3 is connected to the end (one end) 11 of the rotating shaft 10. Further, almost half of the rotating shaft 10 is in a state of being inserted into the cylindrical portion 23 of the joint body 20, and two rows of rolling bearings 8 are provided between a part 13 of the inserted portion and the cylindrical portion 23. 8 is attached. As a result, the rotating shaft 10 is held by the cylindrical portion 23 via the rolling bearing 8 and can rotate with respect to the joint body 20. Further, the rotary shaft 10 is restricted from moving in the axial direction with respect to the cylindrical portion 23 via the rolling bearing 8 and the snap rings 9a and 9b.

[mechanical seal]
The mechanical seal 30 has a static sealing ring 31 and a rotary sealing ring 32, and these sealing rings 31 and 32 are provided between the block portion 22 and the end (other end) 14 of the rotating shaft 10. Has been done. The mechanical seal 30 prevents the fluid 4 flowing between the first flow path 21 in the block portion 22 and the second flow path 12 in the rotating shaft 10 from leaking to the outside. That is, the mechanical seal 30 prevents the fluid 4 flowing between the first flow path 21 and the second flow path 12 from leaking from between the flow paths 21 and 12.

The statically sealed ring 31 is an annular member having a first internal flow path 33, and is entirely made of silicon carbide (SiC). The static sealing ring 31 includes a small diameter portion 35 having a small diameter and a large diameter portion 36 having a diameter larger than that of the small diameter portion 35. The small diameter portion 35 is in a state of being inserted into the hole 24 of the block portion 22, and the static sealing ring 31 is guided by the hole 24 and can move in the axial direction. An O-ring 6 is provided between the small diameter portion 35 and the hole 24, and the static sealing ring 31 is sealed between the small diameter portion 35 and the hole 24 by the O-ring 6, and the first flow path is formed. 21 and the internal flow path 33 side continuous to the 21 and the annular flow path 51 described later are blocked from each other.

An annular sealing surface 41 having a surface finish (for example, wrap finish) is formed so as to project in the axial direction on the axial end surface of the large diameter portion 36 of the static sealing ring 31. A pin 26 projecting in the axial direction is fixed to the block portion 22, and a notch 38 that comes into contact with the pin 26 from the circumferential direction is formed in a part of the large diameter portion 36. When the pin 26 and the notch 38 come into contact with each other, the static sealing ring 31 cannot rotate relative to the block 22. From the above, the static sealing ring 31 is attached to the block portion 22 so as to be non-rotatable and movable in the axial direction.

The rotary sealing ring 32 is an annular member having a second internal flow path 34, and is entirely made of silicon carbide (SiC). The rotary sealing ring 32 has an annular portion 39 in which a second internal flow path 34 is formed, and a tubular portion 40 extending in the axial direction from the radially outer edge portion of the annular portion 39. ing. The tubular portion 40 is fitted onto the end portion 14 of the rotating shaft 10, and can be integrally rotated with the rotating shaft 10 by a rotation stopper structure 60 described later. An O-ring 7 is provided between the end portion 14 of the rotary shaft 10 and the tubular portion 40, and the rotary sealing ring 32 is in a state of being sealed between the rotary shaft 10 (end portion 14). The second flow path 12 and the internal flow path 34 side continuous with the second flow path 12 and the annular space provided with the rolling bearing 8 are blocked from each other.

An annular sealing surface 42 having a surface finish (for example, a wrap finish) is formed on the axial end surface of the annular portion 39. In the block portion 22 of the joint main body 20, concave holes 27 in the axial direction are formed at a plurality of locations in the circumferential direction (only one location is shown in FIG. 1), and the compression coil spring of the mechanical seal 30 is formed in the concave holes 27. (Elastic member) 37 is attached. The spring 37 is provided between the block portion 22 and the static sealing ring 31 (large diameter portion 36), and has a function of pushing the static sealing ring 31 axially toward the rotary sealing ring 32. ..

From the above, as the rotary sealing ring 32 rotates around the center line C of the joint body 20 together with the rotary shaft 10, the sealing surface 42 of the rotary sealing ring 32 is in close contact with the sealing surface 41 of the static sealing ring 31. .. As a result, the fluid 4 flowing between the first flow path 21 and the second flow path 12 can be prevented from leaking from between the flow paths 21 and 12.

[Cooling structure]
An annular space is formed between the cylindrical portion 23 of the joint body 20 and the portion of the rotating shaft 10 inserted into the cylindrical portion 23, and one side of the annular space in the axial direction (lower part of FIG. 1). The rolling bearings 8 and 8 are provided on the side). A sealing member 15 is provided between the inner peripheral surface of the cylindrical portion 23 and the outer peripheral surface of the rotary sealing ring 32 (cylindrical portion 40). The sealing member 15 seals a region on the other side (upper side in FIG. 1) of the annular space in the axial direction, and forms an annular flow path 51 through which cooling water (cooling medium) 50 for cooling the mechanical seal 30 flows. There is.

An introduction port 52 for introducing the cooling water 50 into the flow path 51 is formed in a part of the cylindrical portion 23 so as to penetrate in the radial direction, and a pipe (shown) for introducing the cooling water 50 into the introduction port 52. Is installed. Further, a discharge port 53 for discharging the cooling water 50 from the flow path 51 is formed in a part of the cylindrical portion 23 so as to penetrate in the radial direction, and a pipe for discharging the cooling water 50 is formed in the discharge port 53 ( (Not shown) is attached. The seal member 15 prevents the cooling water 50 introduced into the flow path 51 from leaking to the region where the rolling bearings 8 and 8 are provided.

Even if the cooling water 50 of the flow path 51 passes through the seal member 15 and leaks to one side in the axial direction of the annular space, the pipe connected to the discharge port 54 formed through the cylindrical portion 23 (FIG. The cooling water 50 can be discharged to the outside from (not shown). An annular drain receiver 56 is provided on the inner circumference of the cylindrical portion 23 between the discharge port 54 and the rolling bearing 8. The drain receiver 56 has an annular main body portion 56a and a cylindrical receiving portion 56b extending in the axial direction from the inner peripheral end portion of the main body portion 56a.

An annular pool portion in which the cooling water 50 is temporarily collected by the outer peripheral surface of the receiving portion 56b, the inner peripheral surface of the cylindrical portion 23 facing the outer peripheral surface, and the axial end surface of the main body portion 56a on the receiving portion 56b side. 56c is partitioned. An O-ring 57 is provided between the main body portion 56a of the drain receiver 56 and the cylindrical portion 23, and the drain receiver 56 is sealed between the cylindrical portion 23 by the O-ring 57. As a result, the cooling water 50 that has passed through the seal member 15 and leaked to one side in the axial direction of the annular space is temporarily stored in the pool portion 56c of the drain receiver 56 and then discharged to the outside from the discharge port 54. ..

In addition, another port 55 is formed through the cylindrical portion 23 at different positions in the circumferential direction with respect to the discharge port 54, and this port 55 has a rotary joint 1 as shown in FIG. 1 of the present embodiment. It is used when it is installed upside down with respect to the installation state shown. Therefore, in this embodiment, the port 55 is not used and is therefore sealed by a lid (not shown).

[Anti-rotation structure]
FIG. 2 is an enlarged vertical sectional view of a main part of FIG. The rotary joint 1 is provided with a detent structure 60 for detenting the rotary sealing ring 32 with respect to the rotary shaft 10. The detent structure 60 includes a drive ring 61, a first detent portion 62 that detents the drive ring 61 with respect to the rotating shaft 10, and a second detent ring 32 that detents the rotary sealing ring 32 with respect to the drive ring 61. It is provided with a detent portion 63. The drive ring 61 has a rotary shaft 10 in a state where the end surface 61a on one side in the axial direction (upper side in FIG. 2) faces the end surface 43 (end surface of the tubular portion 40) on the opposite side to the seal surface 42 of the rotary sealing ring 32. It is arranged on the outer peripheral side of.

The first detent portion 62 includes a first key groove 64 formed on the inner circumference of the drive ring 61, a second key groove 65 formed on the outer circumference of the rotating shaft 10, and first and second key grooves 64. , 65 and the key member 66 fitted to the 65. The first key groove 64 is formed over the entire length in the axial direction at one location in the circumferential direction of the inner circumference of the drive ring 61. The second key groove 65 is formed in a concave shape at one position in the circumferential direction of the outer circumference of the rotating shaft 10 so as to face the first key groove 64. Further, the second key groove 65 is formed to be longer in the axial direction than the first key groove 64.

The key member 66 is formed in a rectangular parallelepiped shape, for example, and a part 66a thereof is fitted in the first key groove 64 and another portion 66b is fitted in the second key groove 65. The axial length of the key member 66 is formed to be the same as the axial length of the second key groove 65. As a result, the key member 66 is restricted from moving in the axial direction with respect to the rotating shaft 10. From the above, the drive ring 61 is rotatably stopped with respect to the rotating shaft 10 by the first detent portion 62.

The second detent portion 63 is composed of a concave portion 67 formed on the end surface 43 of the rotary sealing ring 32 and a convex portion 68 formed on the end surface 61a of the drive ring 61 and engaged with the concave portion 67. ing. One or a plurality of recesses 67 (only one is shown in FIG. 2) are formed on the end surface 43 of the rotary sealing ring 32 at predetermined intervals in the circumferential direction. Each recess 67 is formed over the entire thickness of the end face 43 in the radial direction (left-right direction in FIG. 2).

The convex portions 68 are formed on the end surface 61a of the drive ring 61 in the same number as the concave portions 67 at predetermined intervals in the circumferential direction. Each convex portion 68 is formed so as to project from the end surface 61a in the axial direction (upper side in FIG. 2) and is formed over the entire thickness of the end surface 61a in the radial direction (left-right direction in FIG. 2), and the corresponding concave portion 67 is formed. Is engaged in. As a result, the rotary sealing ring 32 is rotatably stopped with respect to the drive ring 61 by the second detent portion 63.

With the above configuration, the rotary sealing ring 32 is rotatably stopped by the first and second detent portions 62 and 63 with respect to the rotary shaft 10 via the drive ring 61. Since the concave portion 67 and the convex portion 68 of the second detent portion 63 are formed over the entire radial thickness of the corresponding end faces 43, 61a, when the rotary sealing ring 32 rotates together with the rotary shaft 10. In addition, the reaction force acting on the rotary sealing ring 32 from the key member 66 via the drive ring 61, the concave portion 67 and the convex portion 68 (the force acting in the direction of suppressing the relative rotation with respect to the rotating shaft 10) is applied to the rotary sealing ring 32. It can be received over the entire radial thickness.

As a result, unlike the conventional case, a part of the radial thickness of the rotary sealing ring 32 does not receive the reaction force from the key member 66 in a concentrated manner. Therefore, the rotary sealing ring 32 caused by the rotation prevention structure 60 Damage can be effectively suppressed.
Further, since the rotary sealing ring 32 is integrated with the drive ring 61 by engaging the concave portion 67 and the convex portion 68 with each other, compared with the case where the rotary sealing ring 32 and the drive ring 61 are integrated by shrink fitting. Therefore, the structure is inexpensive, and damage to the rotary sealing ring 32 due to shrink fitting can be prevented.

The drive ring 61 has a ring main body portion 69 and an annular flange portion 70 projecting radially outward, which is integrally formed on one side in the axial direction (upper side in FIG. 2) of the ring main body portion 69. There is. The outer diameter of the ring main body 69 is set smaller than the inner diameter of the receiving portion 56b of the drain receiving 56. Further, the flange portion 70 is arranged on one side (seal member 15 side) in the axial direction from the receiving portion 56b of the drain receiving portion 56, and the outer diameter of the flange portion 70 is set to be larger than the outer diameter of the receiving portion 56b. Has been done.

As a result, in the present embodiment, the annular gap S formed between the outer peripheral surface of the ring main body 69 and the inner peripheral surface of the receiving portion 56b has a collar on one side in the axial direction (upper side in FIG. 2). Since it is covered by the portion 70, the cooling water 50 leaking from the flow path 51 through the seal member 15 can be guided to the pool portion 56c of the drain receiver 56. As a result, it is possible to prevent the cooling water 50 from passing through the gap S and leaking to the region where the rolling bearings 8 and 8 are provided.

Further, since the outer diameter of the drive ring 61 is increased by the flange portion 70, the moment (angular momentum) around the axis (center line C) of the drive ring 61 is increased. As a result, the posture of the rotational movement of the rotary sealing ring 32 that rotates integrally with the drive ring 61 is stabilized, so that the vibration (axial runout) of the rotary sealing ring 32 is suppressed. As a result, the durability of the rotary sealing ring 32 can be improved.

[Other]
It should be noted that the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is indicated by the scope of claims, not the above-mentioned meaning, and is intended to include meaning equivalent to the scope of claims and all modifications within the scope.

For example, the rotary joint 1 may be installed upside down with respect to the installation state shown in FIG. Further, in the above embodiment, the concave portion 67 is formed on the rotary sealing ring 32 side and the convex portion 68 is formed on the drive ring 61 side, but the convex portion is formed on the rotary sealing ring 32 side and the drive ring 61 side. A recess may be formed in the. Further, it is not always necessary to form the collar portion 70 on the drive ring 61.

1 Rotary joint 10 Rotating shaft 12 Second flow path 20 Joint body 21 First flow path 22 Block part 23 Cylindrical part 30 Mechanical seal 31 Static sealing ring 32 Rotating sealing ring 41 Sealing surface 42 Sealing surface 43 End surface 60 Anti-rotation structure 61 Drive ring 61a End face 64 1st key groove 65 2nd key groove 66 Key member 67 Concave part 68 Convex part 70 Cylinder part

Claims (2)

A block portion in which the first flow path is formed, and a joint body having a cylindrical portion extending in the axial direction from the block portion,
A rotating shaft that is held rotatably on the inner peripheral side of the cylindrical portion and has a second flow path formed inside.
It has a static sealing ring that is attached to the block portion and has a sealing surface formed therein, and a rotary sealing ring that is arranged on the outer periphery of the rotating shaft and has a sealing surface formed that is slidably in contact with the sealing surface of the static sealing ring. , A mechanical seal that prevents the fluid flowing between the first flow path and the second flow path from leaking to the outside.
A detent structure for detenting the rotary sealing ring with respect to the rotary shaft is provided.
The detent structure
A drive ring arranged on the outer circumference of the rotating shaft with an end surface on one side in the axial direction facing the end surface on the opposite side of the sealing surface of the rotary sealing ring
A first detent portion that detents the drive ring with respect to the rotating shaft,
A second detent portion for detenting the rotary sealing ring with respect to the drive ring is provided.
The second detent portion is
Wherein said end face of the rotary seal ring, and of the end surface of the drive ring, a recess formed throughout the thickness of the radial direction at one side, is formed over the entire thickness of the radial direction in the other surface Rutotomoni It is composed of a convex portion that protrudes in the axial direction from the other surface and is engaged with the concave portion .
The first detent portion is
The first keyway formed on the inner circumference of the drive ring and
A second key groove facing the first key groove and formed on the outer circumference of the rotating shaft,
A rotary joint composed of a key member fitted in the first and second key grooves. The rotary joint according to claim 1, wherein the drive ring has an annular flange portion that projects outward in the radial direction.

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