JP6714473B2 - Rotary joint - Google Patents

Description

The present invention relates to a rotary joint provided with a mechanical seal.

Conventionally, in a device including a fixed-side member and a rotating-side member that rotate relative to each other (for example, a semiconductor manufacturing device, an agitator, a medical device, a food-processing device), a fluid passage of the fixed-side member and a fluid passage of the rotating-side member. In order to connect with each other, a rotary joint is provided between the fixed side member and the rotary side member (for example, refer to Patent Document 1).

Such a rotary joint includes a case body, a rotating body, and a mechanical seal. The case body is fixed to the fixed side member, and the rotating body is rotatably supported with respect to the case body so as to rotate in association with the rotation of the rotating side member. The mechanical seal has a rotary seal ring fixed to the rotating body and a stationary seal ring held by the case body so as to face the rotary seal ring.

The mechanical seal rotates the rotary seal ring integrally with the rotary body when the rotary body rotates in association with the rotation of the rotary member, and slides the seal surface of the rotary seal ring onto the seal surface of the stationary seal ring. The rotary seal ring and the stationary seal ring can be sealed by moving the seal.

JP-A-11-248072

It is said that the mechanical seal of the rotary joint is contaminated with abrasion powder (foreign matter) caused by sliding between the rotary seal ring and the stationary seal ring, especially when the rotary seal ring rotates at a low speed (for example, when the rotating body is started). It causes problems and is not preferable for some types of the above-mentioned device using a rotary joint.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a rotary joint that can effectively suppress generation of abrasion powder in a mechanical seal.

The rotary joint of the present invention includes a cylindrical case body formed by opening a plurality of first flow paths on the inner peripheral side, and a plurality of second flow paths provided on the outer peripheral side and the inner peripheral side. And an outer cylindrical body that is formed so as to pass through in a radial direction across the side of the outer cylindrical body and a case body that is rotatable relative to the case body in the outer cylindrical body, and a plurality of third flow paths are formed to open on the outer peripheral side. Formed between the case body and the outer cylinder body, and a drive source for independently rotating and driving the inner shaft body and the outer cylinder body with respect to the case body and the inner shaft body, respectively. A plurality of first mechanical seals that are provided in the first annular space and partition the first annular space to form a flow path that connects the first flow path and the radially outer opening of the second flow path; Provided in a second annular space formed between the outer cylinder body and the inner shaft body, partitioning the second annular space, and the opening on the radially inner side of the second flow path and the third flow A plurality of second mechanical seals forming a flow path connecting the channels, the first mechanical seal is attached to an inner peripheral side of the case body, and has a ring-shaped first sealing surface. And a second sealing ring attached to the outer peripheral side of the outer cylindrical body and having an annular second sealing surface facing the first sealing surface, wherein the second mechanical seal is the outer cylindrical body. A third sealing ring having an annular third sealing surface attached to the inner peripheral side thereof, and an annular fourth sealing surface having an annular fourth sealing surface opposing the third sealing surface attached to the outer peripheral side of the inner shaft body. And four sealing rings.

In the rotary joint configured as described above, the outer cylindrical body is provided with the second sealing ring of the first mechanical seal and the third sealing ring of the second mechanical seal independently of the relative rotation of the inner shaft body with respect to the case body. The first and second mechanical seals can be operated by rotating the drive source together with the drive source. Therefore, from the stage before the inner shaft body starts the relative rotation with respect to the case body, by rotating the outer cylinder body at a predetermined rotation speed by the drive source, regardless of the rotation speed of the relative rotation, The second seal ring of the one mechanical seal is rotated at a predetermined relative rotational speed so that the second seal ring does not come into contact with the first seal ring and the third seal ring of the second mechanical seal does not come into contact with the fourth seal ring. be able to. Therefore, it is possible to operate the first and second mechanical seals so that abrasion powder is not generated as much as possible. As a result, it is possible to effectively suppress the generation of wear debris in the mechanical seal.

Further, in the rotary joint, each of the plurality of first flow paths of the case body, through the flow path of each first mechanical seal, each second flow path of the outer cylindrical body, and each flow path of each second mechanical seal, A plurality of fluid passages connected to the third flow passages of the inner shaft are formed. Therefore, a plurality of fluid passages can be formed with a simple structure in a rotary joint that rotates the outer cylinder independently.

In the rotary joint, the first mechanical seal generates a dynamic pressure between the first seal surface and the second seal surface, and the second seal surface is not in contact with the first seal surface. The second mechanical seal generates a dynamic pressure between the third sealing surface and the fourth sealing surface to keep the fourth sealing surface non-contact with the third sealing surface. It is preferably a mechanical seal that maintains contact.

In this case, since the first and second mechanical seals are dynamic pressure type mechanical seals, when the relative rotation speed of the inner shaft body with respect to the case body tends to be low (for example, when the relative rotation speed is between low speed and high speed). Even if the change is large or the relative rotation is frequently driven and stopped), the abrasion powder in the first and second mechanical seals can be reduced by independently rotating the outer cylinder at a predetermined rotation speed. Can be effectively suppressed.

According to the rotary joint of the present invention, it is possible to effectively suppress the generation of abrasion powder in the mechanical seal.

It is a longitudinal cross-sectional view showing a rotary joint according to an embodiment of the present invention, and is an explanatory view of a case body and an outer cylinder body. It is a longitudinal cross-sectional view showing the rotary joint, and is an explanatory view of an inner shaft body and a drive source. It is sectional drawing which shows the 1st and 2nd mechanical seal arrange|positioned at the upper side, and its periphery.

Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[overall structure]
FIG. 1 is a vertical cross-sectional view showing a rotary joint according to an embodiment of the present invention. In FIG. 1, a rotary joint 1 (hereinafter, also referred to as a joint 1) includes a cylindrical case body 2 and a drive source 4 which are attached to a stationary side member of a rotating device, and an inner portion which is attached to a rotating side member of the rotating device. The shaft body 6 and the outer cylindrical body 5 provided between the case body 2 and the inner shaft body 6 are provided. A first annular space A is formed between the case body 2 and the outer cylinder body 5, and a second annular space B is formed between the outer cylinder body 5 and the inner shaft body 6.

The posture of the joint 1 may be other than the posture shown in FIG. 1, but in the present embodiment, the upper side (driving source 4 side) shown in FIG. The side of the rotating device located opposite the source 4) is “below” the joint 1. In the present invention, the “axial direction” is a direction along the center line of the rotary joint 1 (including a direction parallel to this center line), and includes the case body 2, the drive source 4, the outer cylinder body 5, The center lines of the inner shaft body 6 and first and second mechanical seals 7A and 7B, which will be described later, are configured to coincide with the center line of the rotary joint 1. Further, in the present invention, the “radial direction” is a direction orthogonal to the center line of the rotary joint 1.

[Case body]
The case body 2 includes N (N=2 or more integers, N=2 in the illustrated example) flow path flanges 132 arranged vertically, and flow path flanges 132 that are vertically adjacent to each other with a predetermined interval. It is constituted by (N-1) connecting flanges 133 arranged in between.

These flanges 132 and 133 are formed in an annular shape, and are connected and fixed in a vertically stacked state by bolts 109. As a result, the case body 2 has a tubular structure as a whole. The O-rings 106 are provided between the flow passage flange 132 and the connecting flange 133 which are adjacent to each other.

The flow path flange 132 has an annular projecting portion 135 projecting toward the outer cylinder body 5 which is the radially inner side. Similarly, the connection flange 133 has an annular protrusion 137 that protrudes radially inward. The connecting flange 133 has an outer peripheral side and an inner peripheral side so that a pressure relief hole 138 for releasing the pressure of the first annular space A and the second annular space B passes through the inside of the projecting portion 137 of the connecting flange 133. It is formed so as to penetrate in the radial direction.

A first flow path 134 through which the sealed fluid flows is formed in each of the flow path flanges 132 so as to penetrate therethrough in the radial direction. Examples of the fluid to be sealed include polishing fluid, pressurizing air, cleaning water, pure water, air blowing air, polishing residue liquid, and the like. In this embodiment, air is used as the sealed fluid. In the present embodiment, the fluid to be sealed is a fluid used in an atmospheric pressure state or a fluid used in a pressurized state, but the fluid to be sealed is not limited to this and is used in a depressurized state. It may be a fluid.

Both ends of the first flow path 134 in the road axis direction (the left-right direction in FIG. 1) are open on the inner peripheral side and the outer peripheral side of the flow path flange 132, and in the present embodiment, the outer peripheral side of the flow path flange 132. The opening becomes a connection port to which each of the plurality of pipes of the fixed member is connected. As described above, the case body 2 has a plurality of first flow paths 134 (the number corresponding to the flow path flanges 132).

[External cylinder]
The outer cylinder body 5 is concentrically arranged inside the case body 2, and has a straight long cylinder body 110 in the vertical direction, an outer sleeve 111 fitted on the cylinder body 110, and an inner sleeve body 110. It has a fitted inner sleeve 112 and a disc-shaped lid 113 fixed to one axial end (upper end) of the cylinder body 110.

In addition to the outer sleeve 111, a ring-shaped second sealing ring 12 of a first mechanical seal 7A, which will be described later, is fitted to the outer periphery (radially outer side) of the cylinder body 110. The second sealing ring 12 and the outer sleeve 111 are alternately arranged along the axial direction (in other words, the outer sleeve 111 is arranged between the upper and lower second sealing rings 12 and 12). (N-1) outer sleeves 111 are provided, and N second sealing rings 12 are provided. The outer sleeve 111 functions as a spacer between the vertically adjacent second sealing rings 12, 12.

An end sleeve 114</b>A is further fitted above the uppermost second sealing ring 12 on the outer circumference of the cylinder body 110.
A cylindrical pressing member 115A that presses the second sealing ring 12, the outer sleeve 111, and the end sleeve 114A upward is fixed to the lower end of the outer periphery of the cylinder body 110 by a bolt 119A.

An outer restricting portion 110A that projects radially outward is formed on the upper side (one side in the axial direction) of the cylinder body 110. The outer restricting portion 110A restricts upward movement of the second sealing ring 12, the outer sleeve 111, and the end sleeve 114A, which are fitted onto the cylinder body 110.

As described above, by tightening the pressing member 115A with the bolt 119A, all the second sealing ring 12, the outer sleeve 111, and the end sleeve 114A are axially pressed toward the outer restricting portion 110A of the tube body 110. There is.

The pressing force (axial tightening force) by the pressing member 115A becomes uniform in the circumferential direction. Due to this pressing force, the outer sleeve 111 is pressed against the second sealing ring 12 and the end sleeve 114A is pressed against the second sealing ring 12 and the outer restriction portion 110A. As a result, all of the second sealing ring 12, the outer sleeve 111, and the end sleeve 114A are integrated with the tube main body 110, and can rotate integrally with the tube main body 110 due to mutual frictional force.

In addition to the inner sleeve 112, a ring-shaped third sealing ring 14 of a second mechanical seal 7B, which will be described later, is fitted to the inner periphery (radially inner side) of the cylinder body 110. The inner sleeves 112 are arranged alternately along the axial direction (in other words, the outer sleeves 111 are arranged between the upper and lower third sealing rings 14, 14). (N-1) inner sleeves 112 are provided, and N third sealing rings 14 are provided. The inner sleeve 112 functions as a spacer between the vertically adjacent third sealing rings 14, 14.

An end sleeve 114B is further fitted above the uppermost third sealing ring 14 on the inner circumference of the cylinder body 110.
A cylindrical pressing member 115B that presses the third sealing ring 14, the inner sleeve 112, and the end sleeve 114B upward is fixed to the lower end of the inner periphery of the cylinder body 110 by a bolt 119B.

An inner restricting portion 110B is formed on the upper side (one side in the axial direction) of the cylinder body 110 so as to project inward in the radial direction. The inner restricting portion 110B restricts upward movement of the third sealing ring 14, the inner sleeve 112, and the end sleeve 114B, which are fitted in the cylinder body 110.

As described above, by tightening the pressing member 115B with the bolt 119B, all the third sealing ring 14, the inner sleeve 112, and the end sleeve 114B are axially pressed toward the inner restricting portion 110B of the tube body 110. There is.

The pressing force (axial tightening force) by the pressing member 115B becomes uniform in the circumferential direction. Due to this pressing force, the inner sleeve 112 is pressed against the third sealing ring 14, and the end sleeve 114B is pressed against the third sealing ring 14 and the inner restricting portion 110B. As a result, all the third sealing ring 14, the inner sleeve 112, and the end sleeve 114B are integrated with the cylinder main body 110, and can rotate integrally with the cylinder main body 110 due to mutual frictional force.

N (two in the illustrated example) second flow paths 118 through which the fluid to be sealed flows are formed in the cylinder main body 110 so as to penetrate in the radial direction from the outer peripheral side to the inner peripheral side. The respective second flow paths 118 are formed at different height positions (corresponding to the second sealing ring 12 and the third sealing ring 14) in the vertical direction in the cylinder body 110.
Further, a through hole 143 is formed in the cylinder body 110 at a position corresponding to the pressure release hole 138 on the case body 2 side so as to penetrate in the radial direction.

A through hole 111a is formed in the outer sleeve 111 at a position corresponding to the through hole 143 of the cylinder body 110 so as to penetrate in the radial direction. Similarly, a through hole 112a is formed in the inner sleeve 112 at a position corresponding to the through hole 143 of the cylinder body 110 so as to penetrate in the radial direction.
As a result, the pressure in the first annular space A is released to the outside from the pressure relief hole 138 of the case body 2. Further, the pressure in the second annular space B is released to the outside through the through hole 112a of the inner sleeve 112, the through hole 143 of the cylinder body 110, the through hole 111a of the outer sleeve 111, and the pressure relief hole 138 of the case body 2. Be released.

Between the cylinder body 110, the end sleeve 114A and the second seal ring 12, between the cylinder body 110, the outer sleeve 111 and the second seal ring 12, and between the cylinder body 110, the pressing member 115A and the second seal ring 12. O-rings 117A are provided between them. These O-rings 117A prevent the sealed fluid flowing in the second flow channel 118 from invading other flow channels or leaking to the outside.

Between the tube body 110, the end sleeve 114B and the third sealing ring 14, between the tube body 110, the inner sleeve 112 and the third sealing ring 14, and between the tube body 110, the pressing member 115B and the third sealing ring 14. O-rings 117B are provided between them. These O-rings 117B prevent the sealed fluid flowing in the second flow channel 118 from invading other flow channels or leaking to the outside.

A rolling bearing 120 is provided between the outer peripheral surface of the upper end of the cylinder body 110 and the inner peripheral surface of the upper flow path flange 132. A rolling bearing 121 is provided between the outer peripheral surface of the pressing member 115</b>A located on the lower side of the tube main body 110 and the inner peripheral surface of the lower flow path flange 132. Thereby, the outer cylinder body 5 is rotatable with respect to the case body 2.

A rolling bearing 122 is provided between the inner peripheral surface of the upper end of the cylinder body 110 and the outer peripheral surface of the inner shaft body 6. Further, a rolling bearing 123 is provided between the inner peripheral surface of the pressing member 115B located on the lower side of the cylinder body 110 and the outer peripheral surface of the inner shaft body 6. As a result, the outer cylinder body 5 is also rotatable with respect to the inner shaft body 6.

[Inner shaft]
FIG. 2 is the same view as FIG. 1, and is a vertical cross-sectional view showing the joint 1. In FIG. 2, the inner shaft body 6 is attached to the rotation-side member in a state of being arranged concentrically inside the outer cylinder body 5, and is different from the case body 2 attached to the fixed-side member. It is rotatable.
The inner shaft body 6 includes N (two in the illustrated example) split shaft portions 160 arranged vertically and (N-1) connecting shafts arranged between vertically adjacent split shaft portions 160. And a part 161.

These shaft portions 160 and 161 are formed in a cylindrical shape, and are connected and fixed by bolts 163 in a vertically stacked state. As a result, the inner shaft body 6 is a columnar structure as a whole. The inner shaft body 6 may be formed in another shape such as a cylindrical shape as a whole.

Each of the split shaft portions 160 has an annular protrusion 170 that protrudes outward in the radial direction. Similarly, the connecting shaft portion 161 has an annular protruding portion 175 protruding outward in the radial direction. An O-ring 164 is provided between the end of each split shaft 160 on the side of the connecting shaft 161 and the protrusion 175 of the connecting shaft 161. These O-rings 164 prevent the sealed fluid flowing in the third flow path 165, which will be described later, from entering the other flow paths and leaking to the outside.

In the inner shaft body 6, N third flow paths 165 through which the sealed fluid flows are formed. The respective third flow paths 165 are formed inside the inner shaft body 6 at predetermined intervals in the radial direction. Further, the upper end side of each of the third flow paths 165 is open at the outer peripheral surface of the different split shaft portions 160 (the upper split shaft portion 160 and the lower split shaft portion 160). As a result, the upper ends of the third flow paths 165 are opened at different height positions in the vertical direction.

In the present embodiment, two third flow paths 165 are formed in the inner shaft body 6, one of the third flow paths 165 is formed on the center line of the inner shaft body 6, and the other third flow path is formed. The passage 165 is formed in the inner shaft body 6 on the outer peripheral side of the one third flow passage 165.

The one third flow path 165 is formed by penetrating in the axial direction at the central portion of the connecting shaft portion 161 and the flow passage hole 171A formed so as to extend in the axial direction at the central portion of each split shaft portion 160. It has a flow path hole 176. The flow path hole 171A formed in the lower split shaft portion 160 is formed so as to penetrate in the axial direction, and the lower end side of the flow path hole 171A is opened at the lower end surface of the lower split shaft portion 160. ing.

A channel hole 172A extending in the radial direction is formed in the upper split shaft portion 160. The radial inner end of the flow path hole 172A communicates with the upper end portion of the flow path hole 171A, and the radial outer end of the flow path hole 172A opens at the outer peripheral surface of the upper split shaft portion 160.

Therefore, the one third flow passage 165 formed in the central portion (on the center line) of the inner shaft body 6 has the flow passage hole 171A of the lower split shaft portion 160 and the flow passage hole 176 of the connecting shaft portion 161. And the flow path hole 171A and the flow path hole 172A of the upper split shaft portion 160.

The other third flow path 165 has a flow path hole 171B formed by extending axially on the outer peripheral side (radially outside) of the flow path hole 171A in the lower split shaft portion 160, and a radial direction. The flow path hole 172B extends. The lower end side of the flow path hole 171B is opened at the lower end surface of the lower split shaft portion 160. The radial inner end of the flow path hole 172B communicates with the upper end portion of the flow path hole 171B, and the radial outer end of the flow path hole 172B opens at the outer peripheral surface of the lower split shaft portion 160.

As described above, the inner shaft body 6 of the present embodiment has a configuration in which two third flow paths 165 that open on the outer peripheral side are formed, and the flow path holes 172A and 172B formed in each split shaft portion 160. Is an opening hole on the outer peripheral side of the third flow path 165. Each of these third flow paths 165 opens toward the inner peripheral side of the outer tubular body 5, and also opens at different positions in the vertical direction (axial direction). Further, each of the plurality of pipes of the rotation-side member is connected to the openings of the flow path holes 171A and 171B on the lower end surface of the inner shaft body 6.

[Drive source]
In FIG. 2, the drive source 4 drives the outer cylinder body 5 to rotate independently of the case body 2 and the inner shaft body 6, and is configured using a motor, an air turbine, or the like. The drive source 4 is integrally connected to the outer cylinder body 5 so that the outer cylinder body 5 can be rotated at a predetermined rotation speed.

The drive source 4 in this embodiment includes a motor 41, for example, and is fixed to the case body 2. Specifically, a disc-shaped support plate 43 is integrally fixed to the motor 41, and the support plate 43 is fixed by a bolt 44 while being mounted on the upper end surface of the upper flow path flange 132. Has been done.

The motor 41 has an output shaft 42, and the output shaft 42 is fixed by being inserted into the central portion of the lid 113 of the outer tubular body 5. Thus, by rotating the output shaft 42 of the motor 41, the outer cylinder body 5 can be rotated together with the output shaft 42.

At that time, as described above, the outer cylindrical body 5 can be rotated with respect to the case body 2 by the rolling bearings 120 and 121, and can be rotated with respect to the inner shaft body 6 by the rolling bearings 122 and 123. it can. Therefore, the outer cylinder body 5 can be rotated by the motor 41 independently of the relative rotation of the inner shaft body 6 with respect to the case body 2.

[mechanical seal]
In FIG. 2, a first mechanical seal 7A is provided in the first annular space A between the case body 2 and the outer cylinder body 5. N first primary mechanical seals 7A are arranged vertically along the outer tubular body 5. A second mechanical seal 7B is provided in the second annular space B between the outer cylinder body 5 and the inner shaft body 6. N second secondary mechanical seals 7B are arranged side by side along the outer cylinder body 5 in the vertical direction.

The joint 1 of the present embodiment is a multi-channel rotary joint in which a plurality (two in the illustrated example) of each of the first and second mechanical seals 7A and 7B are arranged in the axial direction.
Each of the first mechanical seals 7A partitions the first annular space A and connects the first flow path 134 in the case body 2 and the opening on the radially outer side of the second flow path 118 in the outer tubular body 5 to each other. Is provided to form the.
In addition, each second mechanical seal 7</b>B partitions the second annular space B and defines an opening on the radially inner side of the second flow passage 118 in the outer tubular body 5 and a third flow passage 165 of the inner shaft body 6. It is provided to form a connecting flow path 27.

The functions of the plurality of first mechanical seals 7A are the same, and here, the first mechanical seal 7A arranged on the upper side will be described as a representative. Similarly, the functions of the plurality of second mechanical seals 7B are similar, and here, the second mechanical seal 7B arranged on the upper side will be described as a representative.

<First mechanical seal>
FIG. 3 is a cross-sectional view showing the first and second mechanical seals 7A and 7B arranged on the upper side and the periphery thereof. In FIG. 3, one first flow path 134 that opens on the inner peripheral side of the flow path flange 132 and one second flow path 118 that opens on the outer peripheral side of the tube body 110 open at substantially the same height position. ing. Further, one first mechanical seal 7A is provided between them.

The first mechanical seal 7A is a dynamic pressure type non-contact type mechanical seal, and has a first sealing ring 11, a second sealing ring 12, and a coil spring 13 as an elastic member.
The second sealing ring 12 is integrally rotatably provided on the cylinder body 110 as described above. Both axial end faces of the second seal ring 12 are annular second seal faces 22, 22.

The first sealing ring 11 is made up of a pair of upper and lower parts which are arranged with the second sealing ring 12 interposed therebetween, and the pair of first sealing rings 11 and 11 is a constituent member of one first mechanical seal 7A. Become. Each of the pair of first sealing rings 11 has an annular first sealing surface 20, 20 facing the second sealing surface 22, 22 of the second sealing ring 12, respectively.

Each first sealing ring 11 is formed in an annular shape and is prevented from rotating by the case body 2. In the present embodiment, a locking pin 136 extending axially downward is fixed to the flow path flange 132, and the locking pin 136 is formed at an axial end portion of the upper first sealing ring 11. It is locked in the stop groove 21. As a result, the upper first sealing ring 11 is prevented from rotating around the case body 2.

Further, a locking pin 139 extending upward in the axial direction is fixed to the connecting flange 133, and the locking pin 139 is formed in the locking groove 21 formed at the axial end of the lower first sealing ring 11. Is locked to. As a result, the lower first sealing ring 11 is prevented from rotating around the case body 2.

Dynamic pressure generating grooves 23, 23 are formed on the second sealing surfaces 22, 22 of the second sealing ring 12, respectively. Each dynamic pressure generating groove 23 is formed so that the first sealing surface 20 of the first sealing ring 11 and the second sealing surface 22 of the second sealing ring 12 facing the first sealing surface 20 do not come into contact with each other. It is formed in an appropriate shape so as to generate a dynamic pressure with the relative rotation of the sealing surfaces 20 and 22.

The first sealing ring 11 is manufactured using, for example, stainless steel and a ceramic coating, or stainless steel and silicon carbide. The second sealing ring 12 is made of carbon, for example.

The coil spring 13 is interposed between the first sealing ring 11 and the protruding portion 135 of the flow path flange 132 in a compressed state. Therefore, the elastic restoring force of the coil spring 13 pushes the first sealing ring 11 in the axial direction toward the second sealing ring 12 side. A plurality of coil springs 13 are provided along the circumferential direction. The elastic restoring force of the coil spring 13 is appropriately set so that a predetermined distance can be secured between the first sealing surface 20 of the first sealing ring 11 and the second sealing surface 22 of the second sealing ring 12 by dynamic pressure. ..

Therefore, in the first mechanical seal 7A, when the outer cylindrical body 5 rotates, the second sealing ring 12 can be rotated with respect to the first sealing ring 11 to generate dynamic pressure. As a result, the outer peripheral side of the first mechanical seal 7A and the case body 2 are maintained while maintaining the non-contact state between the first sealing surface 20 of the first sealing ring 11 and the second sealing surface 22 of the second sealing ring 12. It is possible to prevent the sealed fluid passing through the annular first sealing area Sa formed between the (flow passage flange 132 and the connection flange 133) from leaking between the sealing surfaces 20 and 22 to the outside. ..

An O-ring 17A is provided between the inner peripheral surface of the protruding portion 135 of the flow path flange 132 and the outer peripheral surface of the upper first sealing ring 11 facing the protruding portion 135. The O-ring 17A serves as a seal. This prevents the sealed fluid in the first sealed area Sa from leaking to the outside. The upper first sealing ring 11 is fitted and held in the projecting portion 135 of the flow path flange 132 via the O-ring 17A so as to be movable in the axial direction.

An O-ring 18A is provided between the inner peripheral surface of the projecting portion 137 of the connecting flange 133 and the outer peripheral surface of the lower first sealing ring 11 that faces the protruding portion 137. The O-ring 18A seals the function. This prevents the sealed fluid in the first sealed area Sa from leaking to the outside. The lower first seal ring 11 is fitted and held in the axially movable state with respect to the protrusion 137 of the coupling flange 133 via the O-ring 18A.

The second sealing ring 12 is disposed at substantially the same height as the second flow passage 118 of the cylinder body 110, and the flow passage 24 through which the sealed fluid flows extends radially through the outer peripheral side and the inner peripheral side. Is formed. The radially inner opening of the flow path 24 communicates with the radially outer opening of the second flow path 118, and the radially outer opening of the flow path 24 communicates with the first sealing area Sa.

As a result, the second flow path 118 in the outer cylinder body 5 communicates with the first flow path 134 of the case body 2 via the flow path 24 and the first sealed area Sa. Therefore, the flow path 24 is a flow path that connects the first flow path 134 of the case body 2 and the opening of the second flow path 118 of the outer tubular body 5 on the radially outer side.

<Second mechanical seal>
One second flow path 118 that opens on the inner peripheral side of the cylinder body 110 and one third flow path 165 that opens on the outer peripheral side of the split shaft portion 160 open at approximately the same height position. Further, one second mechanical seal 7B is provided between them.

The second mechanical seal 7B is a dynamic pressure type non-contact type mechanical seal, and has a third sealing ring 14, a fourth sealing ring 15, and a coil spring 16 as an elastic member.
As described above, the third sealing ring 14 is provided so as to be integrally rotatable with the barrel main body 110. Both axial end surfaces of the third sealing ring 14 are annular third sealing surfaces 25, 25.

The fourth sealing ring 15 is a pair of upper and lower parts arranged with the third sealing ring 14 sandwiched therebetween, and the pair of fourth sealing rings 15 and 15 is a constituent member of one second mechanical seal 7B. Become. Each of the pair of fourth sealing rings 15 has an annular fourth sealing surface 28, 28 facing the third sealing surface 25, 25 of the third sealing ring 14, respectively.

Each of the fourth sealing rings 15 is formed in an annular shape and is prevented from rotating by the inner shaft body 6. In the present embodiment, a locking pin 173 that extends downward in the axial direction is fixed to the split shaft portion 160, and this locking pin 173 is formed at the axial end of the upper fourth sealing ring 15. It is locked in the stop groove 29. As a result, the upper fourth sealing ring 15 is prevented from rotating around the inner shaft body 6.

Further, a locking pin 177 extending upward in the axial direction is fixed to the connecting shaft portion 161, and the locking pin 177 is a locking groove formed at the axial end of the lower fourth sealing ring 15. It is locked to 29. As a result, the lower fourth sealing ring 15 is prevented from rotating on the inner shaft body 6.

Dynamic pressure generating grooves 26, 26 are formed in the third sealing surfaces 25, 25 of the third sealing ring 14, respectively. Each of the dynamic pressure generating grooves 26 is formed so that the fourth sealing surface 28 of the fourth sealing ring 15 and the third sealing surface 25 of the third sealing ring 14 facing the fourth sealing surface 28 do not come into contact with each other. It is formed in an appropriate shape so as to generate a dynamic pressure with the relative rotation of the seal surfaces 25, 28.

The third sealing ring 14 is manufactured using carbon, for example. The fourth sealing ring 15 is manufactured using, for example, stainless steel and a ceramic coating, or stainless steel and silicon carbide.

The coil spring 16 is interposed between the fourth sealing ring 15 and the protruding portion 170 of the split shaft portion 160 in a compressed state. Therefore, the elastic restoring force of the coil spring 16 pushes the fourth sealing ring 15 in the axial direction toward the third sealing ring 14 side. A plurality of coil springs 16 are provided along the circumferential direction. The elastic restoring force of the coil spring 16 is appropriately set so that a predetermined distance can be secured between the third sealing surface 25 of the third sealing ring 14 and the fourth sealing surface 28 of the fourth sealing ring 15 by dynamic pressure. ..

Therefore, in the second mechanical seal 7B, when the outer tubular body 5 rotates, the third sealing ring 14 can be rotated with respect to the fourth sealing ring 15 to generate dynamic pressure. Thereby, while maintaining the non-contact state between the third seal surface 25 of the third seal ring 14 and the fourth seal surface 28 of the fourth seal ring 15, the inner peripheral side of the second mechanical seal 7B and the inner shaft of the second mechanical seal 7B. The sealed fluid passing through the annular second sealing region Sb formed between the body 6 (the split shaft portion 160 and the connecting shaft portion 161) is prevented from leaking to the outside from between the seal surfaces 25 and 28. be able to.

An O-ring 17B is provided between the outer peripheral surface of the protruding portion 170 of the split shaft portion 160 and the inner peripheral surface of the upper fourth sealing ring 15 that faces the protruding portion 170, and the sealing function of the O-ring 17B is provided. This prevents the sealed fluid in the second sealed area Sb from leaking to the outside. The upper fourth sealing ring 15 is fitted and held in the axially movable state with respect to the protruding portion 170 of the split shaft portion 160 via the O-ring 17B.

An O-ring 18B is provided between the outer peripheral surface of the protruding portion 175 of the connecting shaft portion 161 and the inner peripheral surface of the lower fourth sealing ring 15 that faces the protruding portion 175, and the O-ring 18B seals the O-ring 18B. The function prevents the sealed fluid in the second sealed area Sb from leaking to the outside. The lower fourth sealing ring 15 is fitted and held in the axially movable state with respect to the protruding portion 175 of the connecting shaft portion 161 via the O-ring 18B.

The fourth sealing ring 15 is arranged at substantially the same height as the second flow passage 118 of the cylinder main body 110, and the flow passage 27 through which the sealed fluid flows extends radially through the outer peripheral side and the inner peripheral side. Is formed. The radially outer opening of the flow path 27 communicates with the radially inner opening of the second flow path 118, and the radially inner opening of the flow path 27 communicates with the second sealing area Sb.

As a result, the second flow passage 118 in the outer tubular body 5 communicates with the third flow passage 165 of the inner shaft body 6 via the flow passage 27 and the second sealed region Sb. Therefore, the flow path 27 serves as a flow path that connects the third flow path 165 of the inner shaft body 6 and the radially inner opening of the second flow path 118 of the outer tubular body 5.

As described above, the first flow path 134 of the case body 2, the second flow path 118 of the outer tubular body 5, and the inner shaft body 6 are formed by the flow paths 24 and 27 constituted by the first and second mechanical seals 7A and 7B. Is connected to the third flow path 165. The first flow path 134, the flow path 24, the second flow path 118, the flow path 27, and the third flow path 165 constitute one independent fluid passage 8. As a result, as shown in FIG. 2, a plurality of (two in the present embodiment) fluid passages 8 are formed in the joint 1.

As described above, according to the rotary joint 1 of the present embodiment, the outer cylinder body 5 is connected to the seal ring 12 of the first and second mechanical seals 7A and 7B independently of the relative rotation of the inner shaft body 6 with respect to the case body 2. , 14 together with the drive source 4, the first and second mechanical seals 7A, 7B can be operated. Therefore, from the stage before the inner shaft body 6 starts the relative rotation with respect to the case body 2, by rotating the outer cylindrical body 5 at a predetermined rotation speed by the drive source 4, the rotation speed of the relative rotation becomes the same. Nevertheless, the second sealing ring 12 of the first mechanical seal 7A should not come into contact with the first sealing ring 11, and the third sealing ring 14 of the second mechanical seal 7B should not come into contact with the fourth sealing ring 15. , And each can be rotated at a predetermined relative rotation speed. Therefore, it is possible to operate the first and second mechanical seals 7A and 7B so that abrasion powder is not generated as much as possible. As a result, it is possible to effectively suppress the generation of abrasion powder in the first and second mechanical seals 7A and 7B.

Further, in the rotary joint 1, each of the plurality of first flow paths 134 of the case body 2, the flow path 24 of each first mechanical seal 7A, each second flow path 118 of the outer tubular body 5, and each second mechanical seal. A plurality of fluid passages 8 connected to the respective third passages 165 of the inner shaft body 6 are formed via the passages 27 of 7B. Therefore, in the rotary joint 1 that rotates the outer cylinder body 5 independently, a plurality of fluid passages 8 can be formed with a simple configuration.

Further, since the first and second mechanical seals 7A and 7B are dynamic pressure type non-contact type mechanical seals, when the relative rotation speed of the inner shaft body 6 with respect to the case body 2 tends to be low (for example, the relative rotation speed is Even when the rotation speed greatly changes between low speed and high speed, or when the relative rotation is frequently driven and stopped), by independently rotating the outer cylinder body 5 at a predetermined rotation speed, Further, it is possible to effectively suppress the generation of abrasion powder on the second mechanical seals 7A and 7B.

It should be considered that the embodiments disclosed this time are exemplifications in all points and not restrictive. The scope of the present invention is shown not by the above meaning but by the scope of the claims, and is intended to include the meaning equivalent to the scope of the claims and all modifications within the scope. For example, the rotary joint 1 in the above embodiment is arranged so that its axial direction is the vertical direction, but it may be arranged so that the axial direction is the horizontal direction.

The first and second mechanical seals 7A and 7B in the above embodiment are dynamic pressure type non-contact mechanical seals. For example, nitrogen gas or air is transferred from the outside to the first seal ring 11 and the fourth seal ring 15. Is a static pressure type non-contact type mechanical seal that generates a static pressure to bring the first sealing ring 11 and the second sealing ring 12, the fourth sealing ring 15 and the third sealing ring 14 into non-contact with each other. Good.
Further, in the rotary joint 1 in the above embodiment, the case body 2 is attached to the fixed side member and the inner shaft body 6 is attached to the rotary side member, but the inner shaft body 6 is attached to the fixed side member and the rotary side member is attached. The case body 2 may be attached.

DESCRIPTION OF SYMBOLS 1 rotary joint 2 case body 4 drive source 5 outer cylinder body 6 inner shaft body 7A first mechanical seal 7B second mechanical seal 11 first seal ring 12 second seal ring 14 third seal ring 15 fourth seal ring 20 first Seal surface 22 Second seal surface 24 Flow path 25 Third seal surface 27 Flow path 28 Fourth seal surface 118 Second flow path 134 First flow path 165 Third flow path A First annular space B Second annular space

Claims (2)

A tubular case body attached to the fixed-side member, in which a plurality of first flow paths are formed with openings on the inner peripheral side,
An outer cylinder body provided in the case body, wherein a plurality of second flow passages are formed so as to penetrate in the radial direction over the outer peripheral side and the inner peripheral side,
Attached to the rotary side member, and is provided in said barrel body as possible rotation with respect to the case body, and the shaft member among a plurality of third flow passage is formed open at the outer peripheral side,
A drive source that is fixed to the case body and that rotates the outer cylinder body independently of each of the case body and the inner shaft body;
It is provided in a first annular space formed between the case body and the outer cylinder body, and partitions the first annular space to define an opening on the radially outer side of the first flow path and the second flow path. A plurality of first mechanical seals forming a connecting flow path,
It is provided in a second annular space formed between the outer cylinder body and the inner shaft body, partitions the second annular space, and an opening on the radially inner side of the second flow path and the third flow path. A plurality of second mechanical seals that form a flow path that connects the
The first mechanical seal is attached to an inner peripheral side of the case body, is attached to a first sealing ring having an annular first seal surface, and is attached to an outer peripheral side of the outer cylindrical body, and is opposed to the first seal surface. A second sealing ring having an annular second sealing surface to
The second mechanical seal is attached to the inner peripheral side of the outer tubular body, and is attached to the outer peripheral side of the third sealing ring having an annular third seal surface and the inner shaft body, and is attached to the third seal surface. A fourth sealing ring having an opposing annular fourth sealing surface, and a rotary joint. The first mechanical seal generates a dynamic pressure between the first seal surface and the second seal surface and maintains the second seal surface in a non-contact state with the first seal surface. And
The second mechanical seal is a mechanical seal that generates a dynamic pressure between the third sealing surface and the fourth sealing surface and maintains the fourth sealing surface in a non-contact state with the third sealing surface. The rotary joint according to claim 1.

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