JP2022172542A - mechanical seal - Google Patents

Abstract

To maintain sealing performance even when a rotary shaft being rotated changes its inclination angle.SOLUTION: A mechanical seal 10 includes a rotary unit 11 having a rotary seal ring 16 and rotatable integrally with a rotary shaft 8, a stationary unit 12 having stationary seal rings 17-1, 17-2 for sealing between the rotary seal ring 16 and itself, and a supporting unit 13 for supporting the stationary unit 12, the supporting unit 13 having an outside ring 60 having a concave surface 61 in the inner periphery, the stationary unit 12 having a spherical ring 18 having a convex surface 24 on the outer periphery for face-contacting the concave surface 61, holding rings 19-1, 19-2 integrated with the spherical ring 18 and holding the stationary seal rings 17-1, 17-2, respectively, and a bearing block 21 laid between the spherical ring 18 and the rotary unit 11 for making the spherical ring 18 follow the inclination of the rotary shaft 8.SELECTED DRAWING: Figure 1

Description

The present invention relates to mechanical seals.

In various types of rotating equipment, as a device for sealing internal fluid between the equipment casing and the rotating shaft, there is a rotating seal ring that rotates integrally with the rotating shaft, and the rotating seal ring that is provided on the equipment casing side. A mechanical seal is known that includes a stationary seal ring for sealing therebetween (see, for example, US Pat.

JP 2019-138334 A

In a rotating device, the axis of rotation may be tilted with respect to the casing of the device, for example, due to the assembly accuracy of each part. In this case, it is necessary to attach the mechanical seal to the rotary device in accordance with the inclination of the rotary shaft. In the mechanical seal disclosed in Patent Document 1, the stationary unit is provided with an outer ring having a concave curved surface on the inner circumference and an inner ring having a convex curved surface on the outer circumference that contacts the concave curved surface, and is in a fixed state. It is possible to tilt the inner ring with respect to the outer ring. Therefore, when a mechanical seal is attached to a rotating device, the inner ring and the stationary seal ring integrated with the inner ring are inclined in accordance with the inclination of the rotating shaft, thereby creating a gap between the stationary seal ring and the rotary seal ring. Sealing performance is ensured.

In the mechanical seal disclosed in Patent Document 1, the sealing performance is maintained when the rotary shaft rotates while maintaining the initial inclination angle during assembly. However, when the rotating shaft changes its inclination angle while rotating, the stationary unit cannot follow the rotating shaft, and it may become difficult to maintain the sealing performance.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a mechanical seal capable of maintaining sealing performance even when the rotation shaft changes its inclination angle while rotating.

(1) The mechanical seal of the present invention comprises a rotary unit having a rotary seal ring and capable of rotating integrally with a rotary shaft; a stationary unit having a stationary seal ring for sealing between the rotary seal ring; a support unit for supporting a stationary unit, the support unit having an outer ring having an inner circumference with a concave curved surface shaped along a phantom spherical surface having a center point on the axis of the support unit; The unit includes: a spherical ring whose outer circumference is restricted from rotating with respect to the outer ring and has a convex curved surface in surface contact with the concave curved surface; a retaining ring that is integral with the spherical ring and retains the stationary seal ring; a bearing block that is integral with the spherical ring and interposed between the spherical ring and the rotating shaft or the rotating unit for allowing the spherical ring to follow the inclination of the rotating shaft.

According to the mechanical seal, when the inclination angle of the axis of the rotary shaft changes while the rotary shaft rotates, the bearing block causes the spherical ring to follow the inclination angle, and the inclination angle of the axis of the spherical ring also changes. . Even if the inclination angle of the spherical ring changes, the spherical ring is supported by the outer ring while allowing the change by the concave curved surface. As the inclination angle of the spherical ring changes, the inclination angle of the stationary seal ring held by the retaining ring integral with the spherical ring also changes. As a result, even if the inclination angle of the rotary shaft changes while rotating, the relative postures of the rotary seal ring and the stationary seal ring do not change, and the sealing performance is maintained.

(2) When the rotating shaft swings, the rotating shaft changes its tilt angle and is displaced (eccentrically) in the radial direction. Therefore, preferably, the support unit has a support block provided with a guide groove that supports the outer ring in a radially displaceable manner.
According to this configuration, even if the rotating shaft changes its inclination angle and is displaced in the radial direction, the outer ring that supports the spherical ring is displaced in the radial direction, so that the stationary unit is attached to the rotating shaft. follows. As a result, there is no relative change in posture between the rotary seal ring and the stationary seal ring, and the sealing performance is maintained.

(3) In particular, when the rotating shaft is tilted so that the tilt angle changes with a position on one side or the other side in the axial direction of the mechanical seal as a reference point, the rotating shaft, the rotating unit, and the stationary unit An axial displacement component occurs between Therefore, preferably, the bearing block has a plurality of rollers, a rolling bearing that allows axial displacement between the rollers and a raceway surface with which the rollers are in rolling contact, and a bearing that holds the rolling bearings. and a bearing case connected to the spherical ring.
According to the above configuration, the rotating shaft and rotating unit are rotatable with respect to the bearing block of the stationary unit, and axial displacement is allowed between the bearing block and the rotating shaft and rotating unit. In other words, slippage occurs in the axial direction between the rollers and the raceway surface, and the axial displacement component occurring between the rotating shaft/rotating unit and the stationary unit is absorbed by the rolling bearing. As a result, the follow-up of the rotating shaft in the mechanical seal becomes smooth.

(4) In addition, the mechanical seal has a detent mechanism for restricting rotation of the spherical ring with respect to the outer ring, the outer ring having a pin projecting toward the spherical ring, A recess is provided to accommodate the tip of the pin.
According to the above configuration, even if the rotating shaft rotates together with the rotating unit and the stationary seal ring receives a rotating force from the rotating seal ring, and the spherical ring of the stationary unit tries to rotate, the tip of the pin of the outer ring is The spherical ring is prevented from rotating by contacting the inner surface of the concave portion provided in the spherical ring.

(5) Further, in the case of the mechanical seal described in (2) above, the outer ring can be displaced in the radial direction by the guide groove, and the outer ring may also need anti-rotation. Therefore, as a second anti-rotation mechanism for restricting the rotation of the outer ring with respect to the support block, the outer ring has a second pin protruding toward the support block, and the support block is provided with the second pin. A second recess is provided for receiving the tip of the pin.
According to the above configuration, even if the rotating shaft rotates together with the rotating unit and the stationary seal ring receives a rotating force from the rotating seal ring and the outer ring tries to rotate together with the spherical ring of the stationary unit, the outer ring has The tip of the second pin contacts the inner surface of the second recess provided in the support block to prevent rotation of the outer ring.

(6) Preferably, one or both of the guide groove and the sliding surface of the outer ring that slides in contact with the guide groove are provided with a coating for reducing the coefficient of friction.
According to the above configuration, the radial displacement of the outer ring with respect to the guide groove of the support block is smooth.

(7) Preferably, one or both of the concave curved surface of the outer ring and the convex curved surface of the spherical ring are provided with a coating for reducing frictional resistance.
According to the above configuration, the change in attitude of the spherical ring with respect to the outer ring is smooth.

(8) Preferably, the stationary unit includes a first annular seal member that seals between the spherical ring and the retaining ring; a second annular sealing member sealing between the outer ring.
According to the above configuration, since the spherical ring and the retaining ring do not slide, there is no need to consider the frictional resistance between them. A sealing member is used. On the other hand, since the spherical ring and the outer ring slide, a second annular sealing member such as an O-ring with low frictional resistance is used to seal between them.

According to the present invention, it is possible to maintain sealing performance even when the rotation shaft changes its inclination angle while rotating.

It is a sectional view of a mechanical seal concerning a first embodiment. FIG. 3 is a cross-sectional view showing an enlarged part of the machine outside of the mechanical seal. It is a sectional view of a mechanical seal concerning a second embodiment. FIG. 4 is a cross-sectional view of a mechanical seal showing a state in which a rotating shaft is whirling;

[Regarding the entire mechanical seal]
FIG. 1 is a cross-sectional view of a mechanical seal 10 according to the first embodiment. A mechanical seal 10 is used in a rotating device 7 such as a pump or an agitator. The rotating equipment 7 comprises a rotating shaft 8 and an equipment casing 9 surrounding the rotating shaft 8 . The mechanical seal 10 seals fluid inside the rotating device 7 between the rotating shaft 8 and the device casing 9 . The rotating shaft 8 is rotatably supported by a bearing (not shown) of the rotating device 7 .

The direction of the invention of this disclosure is defined. A direction along the axis L of the rotating shaft 8 and a direction parallel to the axis L are defined as "axial directions". With respect to the axial direction, the outer side (left side in FIG. 1) of the rotating device 7 is the one side in the axial direction, and is referred to as the "outer side". On the other hand, the inner side (the right side in FIG. 1) of the rotating device 7 is the other side in the axial direction, and is referred to as the "inner side". A direction perpendicular to the axis L is defined as a “radial direction”. A direction along a circle centered on the axis L of the rotating shaft 8 is defined as a “circumferential direction”. That is, the direction of rotation of the rotating shaft 8 is the circumferential direction.

FIG. 1 shows a state in which the axis L of the rotating shaft 8 coincides with the axis of the equipment casing 9 . As will be described later, the inclination angle of the axis L changes while the rotating shaft 8 rotates. The direction of each configuration included in the invention of the present disclosure is defined as a state in which the axis L of the rotating shaft 8 coincides with the axis of the equipment casing 9 unless otherwise specified. Also, this matching state is referred to as a reference state.

The mechanical seal 10 prevents the sealed fluid (solvent, water, oil, etc.) inside the machine from leaking out of the machine. For this purpose, the mechanical seal 10 comprises one rotary seal ring 16 and two stationary seal rings 17-1, 17-2. Between the rotary seal ring 16 and the first stationary seal ring 17-1 and between the rotary seal ring 16 and the second stationary seal ring 17-2, respectively, serve as seal portions for preventing fluid leakage. The mechanical seal 10 according to the first embodiment is a double seal type having two seal portions.

The radially inner side and the axially one side of the seal portion where the first seal surface 16a of the rotary seal ring 16 and the seal surface 17a of the first stationary seal ring 17-1 face (contact) are the outer side area of the machine. becomes. The radially inner side and the other axial side of the seal portion where the second seal surface 16b on the inside of the rotary seal ring 16 and the seal surface 17b of the second stationary seal ring 17-2 face (contact) are the inside of the machine. becomes. A space radially outside the seal portion between the rotary seal ring 16 and the two stationary seal rings 17-1 and 17-2 respectively is a third region K3 filled with a fluid such as quenching oil. Become.

The mechanical seal 10 includes a rotary unit 11 that is integrally rotatable with the rotary shaft 8 and has an annular or tubular shape as a whole, a stationary unit 12 that is provided radially outside the rotary unit 11 and has an annular or tubular shape as a whole, and a generally annular or cylindrical support unit 13 for supporting the stationary unit 12 .

[Regarding the rotating unit 11]
The rotary unit 11 has an annular rotary seal ring 16 , a sleeve 31 and a stopper ring 32 . The rotary seal ring 16 has an annular first seal surface 16a on the outside of the machine and a second annular seal surface 16b on the inside of the machine. The sleeve 31 is a cylindrical member, is fitted around the rotating shaft 8 and is fixed by a set screw 36 . The rotary seal ring 16 is fitted over a portion of the sleeve 31 .

The stopper ring 32 is a cylindrical member and fixed to the inner side of the sleeve 31 . A female thread is formed on the inner periphery of the stopper ring 32 and a male thread is formed on the outer periphery of the sleeve 31 , and the stopper ring 32 is fixed to the sleeve 31 by screwing them together. The stopper ring 32 axially sandwiches the rotary seal ring 16 between itself and a portion of the sleeve 31 to prevent the rotary seal ring 16 from falling off into the machine. A cushion seat 51 made of resin is interposed between the portion of the sleeve 31 and the rotary seal ring 16 . The sleeve 31 has a pin 33 projecting toward the rotary seal ring 16 side. A hole is provided in the inner circumference of the rotary seal ring 16 . By fitting the pin 33 into the hole, the rotary seal ring 16 rotates integrally with the rotary shaft 8 together with the sleeve 31 and the stopper ring 32 . An O-ring 34 seals between the sleeve 31 and the rotating shaft 8 . An O-ring 35 seals between the sleeve 31 and the rotary seal ring 16 .

[Regarding the stationary unit 12]
The stationary unit 12 has a first stationary sealing ring 17-1 and a second stationary sealing ring 17-2 for sealing with the rotating sealing ring 16. As shown in FIG. The first stationary seal ring 17-1 has an annular first seal surface 17a on the inside of the machine. The second stationary seal ring 17-2 has an annular second seal surface 17b on the outboard side. The stationary unit 12 includes, in addition to two stationary seal rings 17-1 and 17-2, a spherical ring 18 and an annular first sealing ring integral with the spherical ring 18 and holding the first stationary sealing ring 17-1. It has a retaining ring 19-1, an annular second retaining ring 19-2 which is integral with the spherical ring 18 and retains a second stationary sealing ring 17-2, and a bearing block 21 which is integral with the spherical ring 18. .

In the form shown in FIG. 1, the spherical ring 18 has a bipartite structure. That is, the spherical ring 18 has a first outboard spherical ring 18-1 and a second inboard spherical ring 18-2. The first spherical ring 18-1 and the second spherical ring 18-2 are connected by bolts 22 and integrated. The second spherical ring 18-2 is provided with a radially penetrating channel 23 for forming part of the third region K3.

The spherical ring 18 has, on its outer periphery, a convex curved surface 24 shaped along a phantom spherical surface having a center point on the axis of the spherical ring 18 (stationary unit 12). In the reference state, the axis of the spherical ring 18 coincides with the axis L of the rotating shaft 8 . The convex curved surface 24 is in surface contact with a concave curved surface 61 of an outer ring 60 which will be described later. A portion of the convex curved surface 24 is provided with a concave portion 25 configured by a hole opening radially outward.

A tip portion 73 c of a pin 73 of a first anti-rotation mechanism 71 (see FIG. 2), which will be described later, is housed in the recess 25 . In this embodiment, a rolling bearing 29 is attached to the concave portion 25 . The pin 73 is housed inside the rolling bearing 29 of the concave portion 25 . This configuration restricts rotation of the spherical ring 18 with respect to the outer ring 60 .

In FIG. 1, the first retaining ring 19-1 is provided on the inner peripheral side of the first spherical ring 18-1. A groove is formed in the inner periphery of the first retaining ring 19-1, and the first stationary seal ring 17-1 is tightly fitted and attached to the groove. A plurality of connecting bolts 26 are attached to the first spherical ring 18-1 along the circumferential direction. A hole through which the connecting bolt 26 is passed is provided in the first retaining ring 19-1. With this configuration, the first retaining ring 19-1 is mounted non-rotatably but axially displaceable with respect to the first spherical ring 18-1. An O-ring 38-1 seals between the first retaining ring 19-1 and the first spherical ring 18-1.

The second retaining ring 19-2 is provided on the inner peripheral side of the second spherical ring 18-2. A groove is formed in the inner periphery of the second retaining ring 19-2, and the second stationary seal ring 17-2 is tightly fitted and attached to the groove. A plurality of bottomed holes 27 are provided in the second spherical ring 18-2 along the circumferential direction. An elastic member (compression coil spring 28 ) is provided in the bottomed hole 27 . The outboard end of the compression coil spring 28 is in contact with the second retaining ring 19-2. Due to the elastic restoring force of the compression coil spring 28, the second stationary seal ring 17-2 is pressed against the rotary seal ring 16, and the rotary seal ring 16 is pressed against the first stationary seal ring 17-1. When the rotary shaft 8 rotates together with the rotary unit 11, the rotary seal ring 16 slides against the stationary seal rings 17-1 and 17-2 respectively. An O-ring 38-2 seals between the second retaining ring 19-2 and the second spherical ring 18-2.

[Regarding the bearing block 21]
FIG. 2 is a cross-sectional view showing an enlarged part of the machine outside of the mechanical seal 10 shown in FIG. The bearing block 21 has a rolling bearing 43 and a tubular bearing case 41 that holds the rolling bearing 43 . The bearing case 41 is connected to the outer side of the spherical ring 18 by bolts 39 . Seals 42 are attached to the inner peripheral side of the bearing case 41 and on both sides in the axial direction of the rolling bearing 43 to prevent foreign matter from entering. An O-ring 37 seals between the bearing case 41 and the first spherical ring 18-1.

The rolling bearing 43 has an outer ring 44 and a plurality of rollers 45 arranged in the circumferential direction, and the rolling bearing 43 of this embodiment is a needle bearing. The outer ring 44 is fitted and fixed to the bearing case 41 . The outer ring 44 has an outer raceway surface 46 with which the rollers 45 roll and contact on the inner peripheral side thereof, and a pair of flanges 47, 47 protruding radially inward on both sides of the outer raceway surface 46 in the axial direction. The position of the roller 45 in the axial direction is restricted by the pair of flanges 47, 47 (that is, displacement in the axial direction is restricted). A radial load (pressurization) is applied to the roller 45 when the assembly of the mechanical seal 10 to the rotating shaft 8 is completed.

In the form shown in FIG. 2, the rolling bearing 43 does not have an inner ring, and a part of the outer peripheral surface of the sleeve 31 serves as an inner raceway surface 48 with which the rollers 45 roll and contact. A part of the sleeve 31 functioning as an inner ring does not have a flange on both sides in the axial direction of the roller 45, and has an inner raceway surface 48 and a cylindrical surface 49 extending from the inner raceway surface 48 on both sides in the axial direction. and With this configuration, a configuration is obtained in which slippage occurs between the rollers 45 and the inner raceway surface 48 in the axial direction. That is, axial displacement is allowed between the rollers 45 and the inner raceway surface 48 .

Thus, the bearing block 21 is interposed between the spherical ring 18 (first spherical ring 18-1) and the rotating unit 11 (sleeve 31). Therefore, when the tilt angles of the rotating shaft 8 and the rotating unit 11 change, the tilt angle of the bearing block 21 also changes so as to follow the change, and the bearing block 21 tilts the spherical ring 18 at the tilt angle. . That is, the bearing block 21 is integrally connected to the spherical ring 18 by the bolts 39 , and the spherical ring 18 follows the tilt of the rotating shaft 8 .

Although not shown, the roller 45 of the rolling bearing 43 may be in rolling contact with a portion of the outer peripheral surface of the rotating shaft 8 . In this case, the bearing block 21 is interposed between the spherical ring 18 (first spherical ring 18 - 1 ) and the rotating shaft 8 .
Moreover, although not shown, the rolling bearing 43 may have an inner ring with which the roller 45 is in rolling contact. In this case, the inner ring is included in the rotating unit 11 .
Even in these cases, the bearing block 21 causes the spherical ring 18 to follow the inclination of the rotating shaft 8 . Further, axial displacement is allowed between the rollers 45 and the inner raceway surface.

[Regarding the support unit 13]
In FIG. 1, support unit 13 supports stationary unit 12 . To that end, the support unit 13 has an outer ring 60 and support blocks 62 supporting the outer ring 60 . The outer ring 60 has, on its inner peripheral side, a concave curved surface 61 that is in surface contact with the convex curved surface 24 of the spherical ring 18 . The concave curved surface 61 has a shape along a phantom spherical surface having a center point on the axis of the support unit 13 . In the reference state, the axis of the support unit 13 coincides with the axis L of the rotating shaft 8 .

In the form shown in FIG. 1, the outer ring 60 includes a first outer ring 60-1 on the outboard side which is in surface contact with the convex curved surface 24 of the first spherical ring 18-1, and a convex curved surface 24 of the second spherical ring 18-2. and a second outer ring 60-2 on the inboard side that makes surface contact with the . The first outer ring 60-1 and the second outer ring 60-2 are not connected, and are held independently in guide grooves 65-1 and 65-2 of the support block 62, which will be described later. A portion of the third region K3 is formed between the first outer ring 60-1 and the second outer ring 60-2.

As will be described later, when the rotation shaft 8 changes the inclination angle, the convex curved surface 24 slides against the concave curved surface 61 . Therefore, the concave curved surface 61 is provided with a coating 81 for reducing the coefficient of friction. A coating 81 may be provided on the convex curved surface 24 . In other words, the coating 81 may be provided on one or both of the concave curved surface 61 and the convex curved surface 24 .

The support block 62 has a plurality of annular blocks 62a extending from the inside of the machine to the outside of the machine. The support block 62 is fixed to the equipment casing 9 by mounting bolts 59 . A through hole 64 forming part of the third region K3 is provided in the center of the support block 62 in the axial direction. A pipe (not shown) through which a fluid such as oil for quenching flows is connected to the through hole 64 .

A first guide groove 65-1 is provided on the outside of the support block 62, and a second guide groove 65-2 is provided on the inside of the support block 62. As shown in FIG. Each of the first guide groove 65-1 and the second guide groove 65-2 is formed by a concave circumferential groove that opens radially inward. A first outer ring 60-1 is radially displaceable and supported in the first guide groove 65-1. A second outer ring 60-2 is supported in the second guide groove 65-2 so as to be radially displaceable.

The first outer ring 60-1 is in sliding contact with the first guide groove 65-1. The second outer ring 60-2 is in sliding contact with the second guide groove 65-2. Therefore, the sliding surface of the first outer ring 60-1 with respect to the first guide groove 65-1 is provided with a coating 80 for reducing the coefficient of friction. A coating 80 is provided on the sliding surface of the second outer ring 60-2 with respect to the second guide groove 65-2 to reduce the coefficient of friction. As described above, in the third region K3, the pressure is higher than inside and outside the machine. Therefore, as shown in FIG. 1, the coating 80 is provided only on the sliding surface away from the third region K3.

A coating 80 may be provided on the side of the first guide groove 65-1 and the second guide groove 65-2. That is, the coating 80 is provided on one or both of the guide grooves 65-1 and 65-2 and the sliding surfaces of the outer rings 60-1 and 60-2 that are in sliding contact with the guide grooves 65-1 and 65-2. It is good if it is

An O-ring 66-1 seals between the first outer ring 60-1 and the first guide groove 65-1. An O-ring 67-1 seals between the first outer ring 60-1 and the first spherical ring 18-1. An O-ring 66-2 seals between the second outer ring 60-2 and the second guide groove 65-2. An O-ring 67-2 seals between the second outer ring 60-2 and the second spherical ring 18-2.

[Regarding the anti-rotation mechanism of the stationary unit 12]
When the rotary shaft 8 rotates together with the rotary unit 11, the rotary seal ring 16 slides against the stationary seal rings 17-1 and 17-2. Therefore, a rotational force acts on the stationary unit 12 having the stationary seal rings 17-1 and 17-2. Therefore, the mechanical seal 10 has a detent mechanism that restricts the rotation of the stationary unit 12 .

Specifically, in FIG. 2, a first detent mechanism 71 for restricting rotation of the spherical ring 18 (first spherical ring 18-1) with respect to the outer ring 60 (first outer ring 60-1). Prepare. The mechanical seal 10 further includes a second anti-rotation mechanism 72 that restricts rotation of the outer ring 60 (first outer ring 60-1) with respect to the support block 62. As shown in FIG.

As the first detent mechanism 71 , the outer ring 60 has a pin (first pin) 73 projecting toward the spherical ring 18 . The pin 73 has a main body portion 73a having a male thread on its outer circumference, and a shaft portion 73b protruding from the main body portion 73a. The external threads of body portion 73 a are attached to threaded holes formed in outer ring 60 . The shaft portion 73b has a spherical tip portion 73c.

As mentioned above, spherical ring 18 is provided with recess 25 . The concave portion 25 is formed by a hole having an inner diameter larger than the diameter of the spherical tip portion 73c. The concave portion 25 accommodates the tip portion 73 c of the pin 73 . In this embodiment, a rolling bearing 29 is attached to the concave portion 25 . The rolling bearing 29 has an inner diameter larger than the diameter of the spherical tip portion 73 c , and the rolling bearing 29 accommodates the tip portion 73 c of the pin 73 . A tip portion 73 c of the pin 73 can contact the inner peripheral surface of the rolling bearing 29 . Note that the rolling bearing 29 may be omitted, in which case the tip portion 73 c of the pin 73 can contact the inner peripheral surface of the recess 25 . Rotation of the spherical ring 18 with respect to the outer ring 60 is restricted by contact of the pin 73 with the rolling bearing 29 mounted in the recess 25 or with the recess 25 .

As the second anti-rotation mechanism 72, the outer ring 60 has a second pin 74 projecting toward the support block 62 side. The pin 74 has a main body portion 74a having a male thread on its outer periphery, and a shaft portion 74b protruding from the main body portion 74a. The external threads of body portion 74 a are attached to threaded holes formed in outer ring 60 . A rolling bearing 75 is attached to the tip portion 74c of the shaft portion 74b.

As described above, the support block 62 has a plurality of annular blocks 62a, of which the outboard annular block 62a functions as a lid member that closes the first guide groove 65-1 from the outboard side. A second concave portion 76 is provided in the outboard annular block 62a. The recess 76 is formed by a hole having an inner diameter larger than the outer diameter of the tip portion 74 c of the pin 74 and further larger than the outer diameter of the rolling bearing 75 . The concave portion 76 accommodates the tip portion 74 c of the pin 74 and the rolling bearing 75 . A rolling bearing 75 attached to the tip portion 74 c of the pin 74 can contact the inner peripheral surface of the recess 76 . Note that the rolling bearing 75 may be omitted, in which case the tip portion 74 c of the pin 74 can contact the inner peripheral surface of the recess 76 . The contact of the pin 74 or the rolling bearing 75 attached to the pin 74 with the recess 25 restricts the rotation of the outer ring 60 with respect to the support block 62 .

In addition, in the first anti-rotation mechanism 71, a rolling bearing may be provided at the tip of the pin 73 like the second anti-rotation mechanism 72. 76 may be provided with a rolling bearing like the first anti-rotation mechanism 71 .

[Regarding the mechanical seal 10 of the first embodiment]
The mechanical seal 10 according to the first embodiment shown in FIG. 1 is a double seal type having one rotary seal ring 16 and two stationary seal rings 17-1 and 17-2. In addition to having two stationary seal rings, the spherical ring 18 has a first outboard spherical ring 18-1, a second inboard spherical ring 18-2, and an outer ring 60. has a first outer ring 60-1 on the outboard side and a second outer ring 60-2 on the inboard side.

[Regarding the mechanical seal 10 of the second embodiment]

FIG. 3 is a cross-sectional view of the mechanical seal 10 according to the second embodiment. The mechanical seal 10 shown in FIG. 3 is a single seal type having one rotary seal ring 16 and one stationary seal ring 17-1. In addition to having one stationary seal ring 17-1, the mechanical seal 10 has one first spherical ring 18-1 and one outer ring 60-1 on the outside of the machine. Compared with the first embodiment shown in FIG. 1, in the second embodiment shown in FIG. Region K3 is omitted, and the others are substantially the same. In the second embodiment shown in FIG. 3, the same reference numerals are assigned to the same configurations as in the first embodiment. In the second embodiment, a compression coil spring that applies an axial biasing force between the stationary seal ring 17-1 and the rotary seal ring 16 is provided in the retaining ring 19-1, although not shown. .

[Regarding the mechanical seal 10 of each embodiment]
As described above, in the mechanical seal 10 of each of the first embodiment and the second embodiment, between the rotary unit 11 having the rotary seal ring 16 and integrally rotatable with the rotary shaft 8 and the rotary seal ring 16 It comprises a stationary unit 12 having a stationary seal ring 17-1 (17-2) for sealing and a support unit 13 for supporting the stationary unit 12. The support unit 13 has an outer ring 60 , and the inner circumference of the outer ring 60 has a concave curved surface 61 shaped along an imaginary spherical surface having a center point on the axis of the support unit 13 .

The stationary unit 12 includes a spherical ring 18 whose rotation with respect to the outer ring 60 is restricted, a retaining ring 19-1 (19-2) integral with the spherical ring 18, and a bearing block 21 integral with the spherical ring 18. have The spherical ring 18 has a convex curved surface 24 on its outer circumference that is in surface contact with the concave curved surface 61 . A retaining ring 19-1 (19-2) retains a stationary seal ring 17-1 (17-2). The bearing block 21 is interposed between the spherical ring 18 and the rotating unit 11 (or the rotating shaft 8 ), and causes the spherical ring 18 to follow the inclination of the rotating shaft 8 .

1 and 3 show a reference state in which the axis L of the rotating shaft 8 coincides with the axis of the equipment casing 9. FIG. FIG. 4 shows a state in which the rotating shaft 8 is oscillating, in which the axis L of the rotating shaft 8 is inclined from the standard state, and the axis L is radially displaced (eccentric). In FIG. 4, the inclination angle of the axis L from the reference state is indicated by "θ", and the eccentricity of the axis L from the reference state is indicated by "E". When the axis L of the rotating shaft 8 has an inclination angle θ, the inclination angle of the axis of the rotary seal ring 16 included in the rotary unit 11 also becomes "θ".

According to the mechanical seal 10 of each embodiment described above, when the inclination angle θ of the axis L of the rotation shaft 8 changes while the rotation shaft 8 is rotating, the bearing block 21 causes the spherical ring 18 to follow the inclination angle θ. Then, the inclination angle of the axis of the spherical ring 18 also changes. Even if the inclination angle of the spherical ring 18 changes, the spherical ring 18 is supported by the outer ring 60 allowing the change by the concave surface 61 . That is, the inclination angle of the spherical ring 18 becomes "θ".
As the inclination angle of the spherical ring 18 changes, the stationary seal ring 17-1 (17-2) held by the retaining ring 19-1 (19-2) integral with the spherical ring 18 also changes in inclination angle. do. That is, the inclination angle of the stationary seal ring 17-1 (17-2) is "θ".
As a result, even when the rotary shaft 8 changes its inclination angle θ while rotating, the relative attitudes of the rotary seal ring 16 and the stationary seal ring 17-1 (17-2) change. seal performance is maintained.

As described above, when the rotating shaft 8 swings, the rotating shaft 8 changes its inclination angle θ and is displaced (eccentrically) in the radial direction as shown in FIG. 4 .
In the mechanical seal 10 of each of the above embodiments, the support block 62 of the support unit 13 is provided with guide grooves 65-1 (65-2) that support the outer ring 60 so as to be displaceable in the radial direction. Therefore, even if the rotating shaft 8 changes the inclination angle θ and is displaced in the radial direction, the outer ring 60 that supports the spherical ring 18 is displaced in the radial direction. Stationary unit 12 follows. As a result, relative posture change between the rotary seal ring 16 and the stationary seal ring 17-1 (17-2) does not occur, and the sealing performance is maintained.

In the example shown in FIG. 4 , the rotation shaft 8 is tilted so that the tilt angle θ changes with a position outside the machine relative to the mechanical seal 10 as a reference point. In this case, an axial displacement component is generated between the rotating shaft 8 and rotating unit 11 and the stationary unit 12 . Therefore, in each of the above-described embodiments, the bearing block 21 for causing the stationary unit 12 to follow the rotating unit 11 has the rolling bearing 43 and the bearing case 41 that holds the rolling bearing 43 and is connected to the spherical ring 18. . The rolling bearing 43 has a plurality of rollers 45 and is configured to allow axial displacement between the rollers 45 and the raceway surface (inner raceway surface 48) with which the rollers 45 are in rolling contact.

As a configuration for this purpose, FIG. 2 will be used as an example. On the other hand, the sleeve 31 as the inner ring does not have flanges on both sides of the roller 45 in the axial direction. Thereby, a structure is obtained in which slippage occurs between the rollers 45 and the inner raceway surface 48 in the axial direction, and axial displacement is allowed between the rollers 45 and the inner raceway surface 48 .

Therefore, the axial displacement component generated between the rotating shaft 8 and rotating unit 11 and the stationary unit 12 is absorbed by the rolling bearing 43 . As a result, the mechanical seal 10 smoothly follows the rotating shaft 8 . Although the roller 45 is allowed to slip in the axial direction with respect to the inner raceway surface 48, it may be configured to allow the slip in the axial direction on the outer ring 44 side.

As described above, the mechanical seal 10 of each embodiment includes the first detent mechanism 71 that restricts rotation of the spherical ring 18 with respect to the outer ring 60 . Even if the rotary shaft 8 rotates together with the rotary unit 11 and the stationary seal ring 17-1 (17-2) receives a rotational force from the rotary seal ring 16, and the spherical ring 18 tries to rotate, the pin 73 of the outer ring 60 does not. tip 73c contacts the inner surface of recess 25 (rolling bearing 29 attached to recess 25) provided in spherical ring 18, and spherical ring 18 is prevented from rotating.
Since the recessed portion 25 (the space on the inner peripheral side of the rolling bearing 29) is larger than the tip portion 73c of the pin 73, the change in the inclination angle of the spherical ring 18 with respect to the outer ring 60 is not hindered.

Furthermore, the mechanical seal 10 of each of the above embodiments includes the second anti-rotation mechanism 72 that restricts rotation of the outer ring 60 with respect to the support block 62, as described above. The rotating shaft 8 rotates together with the rotating unit 11, and the stationary seal ring 17-1 (17-2) receives rotational force from the rotating seal ring 16, and the outer ring 60 rotates together with the spherical ring 18 of the stationary unit 12. Even if you try, the tip of the second pin 74 (rolling bearing 75) of the outer ring 60 contacts the inner surface of the second recess 76 provided in the support block 62, and the outer ring 60 is prevented from rotating. be.
Since the second recess 76 is larger than the tip of the second pin 74 (rolling bearing 75 ), radial displacement of the outer ring 60 with respect to the support block 62 is not hindered.

Rolling bearings 29 and 75 are provided in the first anti-rotation mechanism 71 and the second anti-rotation mechanism 72 . The first pin 73 contacts the inner surface of the recess 25 at an arbitrary position, and the second pin 74 contacts the second recess 76 at an arbitrary position. According to the rolling bearings 29 and 75, the relative positions between the pins 73 and 74 and the mating member are smoothly changed regardless of the position at which the pins 73 and 74 come into contact with the mating member, and the mutual postures are appropriate. , rotation is restricted.

Further, as described above, the concave curved surface 61 of the outer ring 60 is provided with the coating 81 for reducing frictional resistance. Therefore, the attitude of the spherical ring 18 with respect to the outer ring 60 changes smoothly.
Further, as described above, the sliding surface of the outer ring 60 that slides in contact with the guide grooves 65-1 (65-2) is provided with the coating 80 for reducing the coefficient of friction. Therefore, radial displacement of the outer ring 60 with respect to the guide grooves 65-1 (65-2) is smooth.

Furthermore, in each of the above embodiments, the mechanical seal 10 has a plurality of O-rings as described above, and a plurality of types (two types) of O-rings are used. Among the multiple types of O-rings, one is a first annular sealing member (O-ring) made of highly versatile rubber, and the other is a second annular sealing member (O-ring) having a smaller frictional resistance than the first annular sealing member (O-ring). It is a two-ring sealing member (O-ring). Note that the second annular seal member is generally more expensive.

Specifically, the O-ring 67-1 (67-2) that seals between the spherical ring 18 and the outer ring 60 corresponds to the second annular sealing member. Also, the O-rings 66-1 (66-2, 66-2) that seal between the outer ring 60 and the guide grooves 65-1 (65-2) correspond to the second annular sealing member. That is, the O-ring used for the sliding surface when the rotating shaft 8 changes the inclination angle θ or is displaced in the radial direction corresponds to the second annular sealing member.
On the other hand, the O-ring used for the surface that does not slide even when the rotating shaft 8 changes the inclination angle θ or is displaced in the radial direction corresponds to the first annular sealing member. For example, the O-ring 38-1 (38-2) that seals between the spherical ring 18 and the retaining ring 19-1 (19-2) corresponds to the first annular sealing member.

By using two types of O-rings in this manner, the following effects can be achieved.
Even if the rotation shaft 8 changes the inclination angle θ or is displaced in the radial direction, for example, the spherical ring 18 and the retaining ring 19-1 (19-2) do not slide. A first annular sealing member, such as a common O-ring, is used to seal between them without any consideration of resistance. On the other hand, the spherical ring 18 and the outer ring 60 slide, and the outer ring 60 and the guide groove 65-1 (65-2) slide. , a second annular sealing member such as an O-ring with low frictional resistance is used. As a result, for example, the attitude of the spherical ring 18 with respect to the outer ring 60 changes smoothly, and the stationary unit 12 can easily follow the inclination of the rotating shaft 8 .

As described above, according to the mechanical seal 10 according to each of the embodiments described above, the sealing performance of the rotary seal ring 16 and the stationary seal ring 17-1 (17-2) is maintained even if the attitude of the rotating rotary shaft 8 is changed. becomes possible.

〔others〕
In the above-described embodiments, the rotary unit 11 may have a form other than that shown in the figure as long as it has a rotary seal ring 16, and the stationary unit 12 may have a stationary seal ring 17 as shown in the figure. It may be in a form other than that.

The above embodiments are illustrative in all respects and are not restrictive. The scope of rights of the present invention is indicated by the scope of claims rather than the above embodiments, and includes all modifications within the range equivalent to the structure described in the scope of claims.

8 rotary shaft 10 mechanical seal 11 rotary unit 12 stationary unit 13 support unit 16 rotary seal ring 17-1, 17-2 stationary seal ring 18 spherical ring 18-1 first spherical ring 18-2 second spherical ring 19-1 second One retaining ring 19-2 Second retaining ring 21 Bearing block 24 Convex curved surface 25 Concave portion 37 O-ring (first annular seal member)
38-1 O-ring (first annular seal member)
38-2 O-ring (first annular seal member)
41 bearing case 43 rolling bearing 45 roller 48 inner raceway surface (raceway surface)
60 outer ring 60-1 first outer ring 60-2 second outer ring 61 concave surface 62 support block 65-1 first guide groove 65-2 second guide groove 66-1 O-ring (second annular seal member)
66-2 O-ring (second annular seal member)
67-1 O-ring (second annular seal member)
67-2 O-ring (second annular seal member)
71 anti-rotation mechanism 72 second anti-rotation mechanism 73 pin 73c tip 74 second pin 74c tip 76 second recess 80 coating 81 coating L axis

Claims (8)

a rotating unit having a rotating seal ring and capable of rotating integrally with the rotating shaft;
a stationary unit having a stationary seal ring for sealing against said rotating seal ring;
a support unit that supports the stationary unit;
with
The support unit has an outer ring having, on its inner periphery, a concave curved surface shaped along a phantom spherical surface having a center point on the axis of the support unit,
The stationary unit is
a spherical ring having, on its outer periphery, a convex curved surface that is in surface contact with the concave curved surface and whose rotation with respect to the outer ring is restricted;
a retaining ring integral with the spherical ring and retaining the stationary seal ring;
a bearing block that is integral with the spherical ring and interposed between the spherical ring and the rotating shaft or the rotating unit for allowing the spherical ring to follow the inclination of the rotating shaft;
A mechanical seal. 2. The mechanical seal according to claim 1, wherein the support unit has a support block provided with a guide groove that supports the outer ring so as to be radially displaceable. The bearing block is
a rolling bearing having a plurality of rollers and allowing axial displacement between the rollers and a raceway surface with which the rollers are in rolling contact;
3. The mechanical seal according to claim 1, further comprising a bearing case that holds the rolling bearing and is connected with the spherical ring. The outer ring has a pin protruding toward the spherical ring as a detent mechanism for restricting rotation of the spherical ring with respect to the outer ring,
4. The mechanical seal according to any one of claims 1 to 3, wherein the spherical ring is provided with a recess for accommodating the tip of the pin. The outer ring has a second pin projecting toward the support block as a second anti-rotation mechanism for restricting rotation of the outer ring with respect to the support block,
3. The mechanical seal according to claim 2, wherein the support block is provided with a second recess for accommodating the tip of the second pin. 6. The coating according to claim 2 or 5, wherein one or both of the guide groove and the sliding surface of the outer ring that slides in contact with the guide groove are provided with a coating for reducing a coefficient of friction. mechanical seal. 7. The coating according to any one of claims 1 to 6, wherein one or both of the concave curved surface of the outer ring and the convex curved surface of the spherical ring are provided with a coating for reducing frictional resistance. Mechanical seal as described. The stationary unit is
a first annular sealing member for sealing between the spherical ring and the retaining ring;
a second annular seal member that seals between the spherical ring and the outer ring and has a smaller frictional resistance than the first annular seal member;
The mechanical seal according to any one of claims 1 to 7, comprising:

Images