JP6991943B2 - Split mechanical seal - Google Patents

Description

The present invention is applied to shaft sealing of various rotating machines such as pumps and compressors, and is mechanically configured to seal the sealed fluid by a sliding surface between a static sealing ring and a rotating sealing ring. Regarding the seal, in particular, it relates to a split type mechanical seal which is attached to a shaft seal portion of a device such as a large pump which is difficult to disassemble at the time of maintenance, and at least one of a static sealing ring and a rotary sealing ring is divided in the circumferential direction.

The sealing ring divided in the circumferential direction of the conventional split type mechanical seal is formed by breaking the annular sealing ring into a plurality of divided pieces in the circumferential direction. The sealing ring divided in this way has a fastening band and a taper from the outer diameter side in a state where the divided surfaces of the divided pieces are butted against each other and the irregular and fine uneven surfaces of the fractured surfaces are brought into close contact with each other to form an annular shape. By tightening with the holder, the gap between the split surfaces is reduced and the shaft is mounted on the outer circumference.

For example, in the split type mechanical seal of Patent Document 1, the static sealing ring is divided into two in the circumferential direction, a retainer is arranged on the inner diameter side of the static sealing ring, and a taper arranged on the outer diameter side of the static sealing ring. By fixing the holder with the holder to the retainer, the divided pieces are tightened in the circumferential direction and held in an annular shape. A secondary seal such as an O-ring is fitted into the annular recess formed on the outer circumference of the retainer and recessed toward the inner diameter side, and the secondary seal is brought into contact with the inner peripheral surface of the static sealing ring to prevent leakage of the fluid to be sealed. ing.

Japanese Unexamined Patent Publication No. 4-185976 (Page 2, Fig. 1)

However, in the secondary seal used for such a split type mechanical seal, the outer peripheral portion thereof is brought into contact with the inner peripheral surface of the static sealing ring while being fitted in the annular recess of the retainer, and is a rotary machine. There is a risk that the sealed fluid will leak through between the outer peripheral portion of the secondary seal and the inner peripheral surface of the statically sealed ring due to vibration during operation, pressure fluctuation of the sealed fluid, temperature change, and the like. In particular, as shown in Patent Document 1, in the case of an outside type mechanical seal that prevents leakage of the sealed fluid from the inner diameter side to the outer diameter side of the sealed ring, the pressure of the sealed fluid on the high pressure side is the sealing ring. Since it acts on the inner peripheral portion of the seal, that is, it is applied in the outer diameter direction to open the divided surface, there is a possibility that the secondary seal arranged on the sealed fluid side cannot fully exert its sealing function. there were.

The present invention has been made focusing on such a problem, and an object of the present invention is to provide a split type mechanical seal capable of improving the sealing property of a sealing ring divided in the circumferential direction.

In order to solve the above problems, the split type mechanical seal of the present invention is used.
A split mechanical seal comprising a static sealing ring and a rotary sealing ring, wherein at least one of the sealing rings is circumferentially divided.
A retainer that holds the split-type sealing ring from the radial direction on the sealed fluid side,
It is characterized by having a sealing surface in which the split-type sealing ring and the retainer are in contact with each other in the circumferential direction, and a secondary seal having an elastic secondary seal having a pressure receiving surface exposed toward the sealed fluid. It is supposed to be.
According to this feature, the secondary seal placed on the sealed fluid side of the split mechanical seal has elasticity, and the high pressure of the sealed fluid is applied to the pressure receiving surface exposed toward the sealed fluid. As a result, the secondary seal is elastically deformed, the contact pressure of the sealing surface in contact with the sealing ring and the retainer is increased, and the sealing property can be improved.

Preferably, the split-type sealing ring and the retainer form a fitting recess that opens axially toward the sealed fluid and into which the secondary seal is fitted.
According to this, both end portions of the secondary seal fitted in the fitting recess in the radial direction are used as sealing surfaces, and the side surface portions of the secondary seal located at the opening of the fitting recess are used as pressure receiving surfaces. Can be configured. Further, the secondary seal can be easily attached to the fitting recess from the axial direction.

Preferably, the fitting recess is formed by joining the stepped portion formed on the sealing ring and the stepped portion formed on the retainer.
According to this, since the step portion is formed on the secondary seal side of the joint surface between the sealing ring and the retainer, it is difficult for the sealed fluid leaked from the secondary seal to directly flow into the joint surface.

Preferably, the secondary seal is composed of an O-ring having an O-shaped cross-sectional view, and the sealing surface of the secondary seal is with the sealing ring or the retainer constituting the inner bottom surface of the fitting recess. I'm in contact.
According to this, since it is possible to prevent the sealing surface of the secondary seal composed of the O-ring from coming into contact with the joint between the sealing ring and the retainer, the secondary seal may enter the joint due to its deformation. Can be prevented in advance.

Preferably, the mechanical seal is an outside type mechanical seal that seals the sealed fluid on the inner peripheral side of the static sealing ring and the rotary sealing ring.
According to this, the secondary seal is elastically deformed by the sealed fluid sealed on the inner peripheral side of the static sealing ring and the rotary sealing ring, and the sealing property can be ensured.

Preferably, both the static sealing ring and the rotary sealing ring are split type sealing rings divided in the circumferential direction, and the secondary seal can be either the static sealing ring or the rotary sealing ring. Is also provided.
According to this, both the static sealing ring and the rotary sealing ring divided in the circumferential direction can enhance the sealing property.

Preferably, the pressure receiving surface of the secondary seal provided on the static sealing ring and the pressure receiving surface of the secondary seal provided on the rotary sealing ring face each other in the axial direction of the rotating shaft. ing.
According to this, since the pressure receiving surface of the secondary seal on the statically sealed ring side and the pressure receiving surface of the secondary seal on the rotary sealing ring side face each other via the sealed fluid, they are interposed between these pressure receiving surfaces. The pressure of the sealed fluid can be evenly received.

It is sectional drawing which shows the split type mechanical seal in Example 1 of this invention. It is a figure which looked at the stationary sealing ring in FIG. 1 from the outside of the machine in the axial direction. It is an enlarged view of the main part of the static sealing ring and the rotary sealing ring in FIG. It is an enlarged view of the main part which shows an O-ring and a fitting recess. It is a schematic diagram which shows the state which the external force which makes the split body tilt with respect to a retainer is generated from the state of FIG. It is a schematic diagram which shows the modification 1 of the fitting recess of this invention. It is a schematic diagram which shows the modification 2 of the fitting recess of this invention.

A mode for carrying out the split type mechanical seal according to the present invention will be described below based on examples.

The split type mechanical seal according to the first embodiment will be described with reference to FIGS. 1 to 5. First, the split type mechanical seal shown by reference numeral 1 in FIG. 1 has a structure in which both the static sealing ring 10 and the rotary sealing ring 20 are divided in the circumferential direction.

In the split type mechanical seal 1, the sliding surface S of the sealing rings 10 and 20 is used as a sealing surface, from the inner peripheral side which is the high pressure sealed fluid side H to the outer peripheral side which is the low pressure fluid side L (for example, the atmosphere side). An outside-type mechanical seal that seals the fluid that leaks toward the outside, and a stationary type that has a spring 8 that urges the static sealing ring 10 in the axial direction on the housing 2 side. Although it is suitable, it can also be applied to an inside type mechanical seal that seals a fluid that leaks from the outer circumference of the sliding surface toward the inner circumference, and the spring is on the rotating shaft side. It can also be applied to the provided rotary mechanical seal.

In the following, the case of an outside / stationary mechanical seal will be described.

As shown in FIG. 1, the split type mechanical seal 1 (hereinafter, also simply referred to as “mechanical seal 1”) is sealed on the sealed fluid side H between the inner peripheral surface 2a of the housing 2 and the rotating shaft 3. Installed to seal the fluid.

The split type mechanical seal 1 is mainly composed of a case 4, retainers 5A and 5B, a spring 8, a static sealing ring 10, a rotary sealing ring 20, and a collar 6, and before its use, the split type mechanical seal 1 is mainly composed of a case 4. It is integrally configured by the set bolt 25. As will be described later, this mechanical seal 1 is used with the set bolt 25 removed. Note that FIG. 1 shows a state before the set bolt 25 is removed.

In the housing 2, an inner peripheral surface 2a into which the rotation shaft 3 can be inserted is formed on the inside of the machine, and the outside of the machine is open. On the end surface on the outside of the machine, a female screw portion for connecting a fixing bolt 9 is formed. 2b is screwed.

The case 4 has an annular shape having an insertion hole 4a through which the shaft portion of the fixing bolt 9 is inserted, and includes an extension portion 4b extending along the inner peripheral surface 2a of the housing 2. According to this, the case 4 can be fixed to the housing 2 by inserting the fixing bolt 9 into the insertion hole 4a of the case 4 and screwing it into the female screw portion 2b of the housing 2. At this time, as the extending portion 4b of the case 4 is inserted along the inner peripheral surface 2a of the housing 2, the case 4 and the housing 2 are aligned, and in the fixed state by the fixing bolt 9, the extending portion is The O-ring 31 provided in the recess on the outer peripheral surface of 4b is in close contact with the inner peripheral surface 2a of the housing 2 and seals the fluid to be sealed.

Further, the outer peripheral surface of the retainer 5A is covered with a tubular protective cover 23 extending to the outer diameter side of the collar 6 in order to protect the mechanical seal 1. The protective cover 23 is fixed to the outer peripheral surface of the retainer 5A and the holder 14 described later by a band 21 wound around the outer periphery thereof.

The retainer 5A has a cylindrical shape through which the rotating shaft 3 is inserted, and the tubular portion includes an extending portion 51 inserted into the case 4 and an extending portion 52 into which the static sealing ring 10 is attached to the outer peripheral surface. , Equipped with. Further, a flange portion 53 projecting in the outer diameter direction is formed at the central portion in the axial direction of the tubular portion, and a spring 8 is interposed between the flange portion 53 and the case 4. Specifically, the spring 8 is arranged axially in a compressed state between the recess 4c that opens axially to the outside of the machine of the case 4 and the flange portion 53 of the retainer 5A. Therefore, the side end surface inside the machine of the static sealing ring 10 is loaded with an axial urging force from the spring 8 via the retainer 5A, so that the side end surface (sliding surface S) on the outside of the machine of the static sealing ring 10 becomes. It is in close contact with the side end surface (sliding surface S) of the rotary sealing ring 20. According to this, it is possible to improve the axial followability of the side end surface of the static sealing ring 10 with respect to the side end surface of the rotary sealing ring 20. Therefore, the sealing property of the mechanical seal 1 on the sliding surface S can be improved.

The O-ring 32 provided in the recess on the outer peripheral surface of the extending portion 51 closely seals the inner peripheral surface of the case 4. Further, the extension portion 52 is located at a position close to the sliding surface S between the static sealing ring 10 and the rotary sealing ring 20 (the position of the outer end portion of the static sealing ring 10 which is the base end portion of the convex portion 10d described later). An O-ring 33 (secondary seal) that seals the gap between the extension portion 52 and the static sealing ring 10 on the tip side (outside of the machine) of the outer peripheral surface of the extension portion 52. Is placed. The mode of sealing the gap between the retainer 5A and the static sealing ring 10 by the O-ring 33 will be described in detail later.

A knock pin 7 is arranged between the retainer 5A and the case 4 to regulate the relative rotation between the retainer 5A and the case 4. The knock pin 7 is fixed so as to project from the case 4 to the outside of the machine, and is inserted into a plurality of holes 12 provided in the circumferential direction of the retainer 5A.

The static sealing ring 10 is attached to the outer peripheral surface of the extending portion 52 in contact with the flange portion 53 of the retainer 5A. Holders 14 for pressing the static sealing ring 10 from the outer diameter side are fixed to the flange portion 53 of the retainer 5A at a plurality of locations in the circumferential direction by socket bolts 16. Further, an O-ring 34 is arranged between the holder 14 and the static sealing ring 10.

The static sealing ring 10 has a divided structure including divided bodies 10a and 10b (see FIG. 2) which are divided into two in the circumferential direction as described later, and is formed of, for example, silicon carbide or a carbon material. A convex portion 10d projecting to the outside of the machine is formed at the outer end of the stationary sealing ring 10, and the outer end surface of the convex portion 10d is a sliding surface S. Further, a drive pin 13 is arranged between the static sealing ring 10 and the retainer 5A to regulate the relative rotation between the static sealing ring 10 and the retainer 5A. The drive pin 13 is fixed so as to project from the flange portion 53 of the retainer 5A toward the static sealing ring 10, and is inserted into a plurality of drive pin notches 15 formed in the circumferential direction of the static sealing ring 10. .. The number of divisions of the static sealing ring 10 is not limited to two, and may be three or more.

The collar 6 has a cylindrical shape so that the rotating shaft 3 is inserted, and is arranged so as to project from the rotating shaft 3 in the outer diameter direction. The collar 6 is formed with a through hole 6c that penetrates in the radial direction and has a female threaded portion on the inner peripheral surface. The collar 6 can be fixed to the rotating shaft 3 by screwing the pressing screw 28 into the female screw portion of the through hole 6c and pressing the outer peripheral surface of the rotating shaft 3 with the tip of the pressing screw 28.

Further, a retainer 5B is arranged inside the machine of the color 6. The retainer 5B includes a tubular portion 54 through which the rotating shaft 3 is inserted, and a flange portion 55 projecting from the outer end of the tubular portion 54 in the outer radial direction. An annular notch 54a that opens to the outside of the machine is formed on the inner peripheral edge of the tubular portion 54 on the outside of the machine, and an O-ring 35 is arranged on the annular notch 54a on the outside of the machine of the O-ring 35. Is arranged with an annular spacer 17 that is pressed inside the machine by the collar 6. That is, the O-ring 35 is axially sandwiched by the annular notch 54a and the spacer 17, and seals between the rotating shaft 3 and the retainer 5B.

Further, a knock pin 18 is arranged between the retainer 5B and the collar 6 to regulate the relative rotation between the retainer 5B and the collar 6. The knock pin 18 is fixed so as to project from the collar 6 to the inside of the machine, and is inserted into a plurality of holes 27 provided in the circumferential direction of the retainer 5B.

Further, a rotary sealing ring 20 is attached to the outer peripheral surface of the tubular portion 54 of the retainer 5B. An O-ring 36 (secondary seal) is arranged on the outer peripheral surface of the inner end of the tubular portion 54 to seal the gap between the tubular portion 54 of the retainer 5B and the rotary sealing ring 20. The mode of sealing the gap between the retainer 5B and the rotary sealing ring 20 by the O-ring 36 will be described in detail later.

Further, holders 22 for pressing the rotary sealing ring 20 from the outer diameter side are fixed to the flange portion 55 of the retainer 5B at a plurality of locations in the circumferential direction by socket bolts 24. Further, an O-ring 37 is arranged between the holder 22 and the rotary sealing ring 20.

The rotary sealing ring 20 has a split structure that is divided into two in the circumferential direction like the static sealing ring 10, and is made of a material such as silicon carbide or carbon. The machine inner end surface of the rotary sealing ring 20 is formed flat and functions as a sliding surface S that is in sliding contact with the convex portion 10d. Further, a drive pin 19 is arranged between the rotary sealing ring 20 and the retainer 5B to regulate the relative rotation between the rotary sealing ring 20 and the retainer 5B. The drive pin 13 is fixed so as to project from the flange portion 55 of the retainer 5B toward the rotary sealing ring 20, and is inserted into a plurality of drive pin notches 26 formed in the circumferential direction of the rotary sealing ring 20. .. The number of divisions of the rotary sealing ring 20 is not limited to two, and may be three or more.

The set bolt 25 sets the axial length of the mechanical seal 1 in the set state, integrates the mechanical seal 1, and is removed after the mechanical seal 1 is attached to the device.

Next, with reference to FIG. 2, the statically sealed ring 10 and the rotationally sealed ring 20 of this embodiment (hereinafter, when the statically sealed ring and the rotationally sealed ring are collectively referred to as a "sealed ring", may be simply referred to as a "sealed ring". ) Will be described. The present invention can be similarly applied to both the statically sealed ring 10 and the rotary sealing ring 20, but the present invention will be described below by taking the statically sealed ring 10 as an example. Furthermore, FIG. 2 illustrates a state in which the static sealing ring 10 is viewed from the outside of the machine in the axial direction.

As shown in FIG. 2, the static sealing ring 10 is composed of the divided bodies 10a and 10b which are divided by applying an external force to the annular body formed in an integrally annular shape. That is, the divided surfaces 11 and 11 of the divided bodies 10a and 10b are naturally fractured cross sections that are spontaneously fractured without machining, and are composed of a large number of complicated and minute uneven surfaces (enlarged portion in FIG. 2) due to fracture. Since the resulting divided surfaces 11 precisely complement each other and match each other, a high sealing function can be obtained.

Next, the mounting mode of the sealing ring of this embodiment will be described with reference to FIGS. 3 to 5. Since the mounting mode of the static sealing ring 10 is substantially the same as the mounting mode of the rotary sealing ring 20, the mounting mode of the static sealing ring 10 to the retainer 5A and the holder 14 will be described as an example.

As shown in FIG. 3, the static sealing ring 10 has a tapered surface 10c inclined so as to gradually expand the diameter toward the inside of the axial machine at a substantially central portion in the axial direction of the outer peripheral surface. Further, the holder 14 includes a base portion 14a fixed to the flange portion 53 of the retainer 5A, and a hook-shaped portion 14b extending axially from the inner diameter side of the base portion 14a and extending with its tip bent in the inner diameter direction. There is. The O-ring 34 described above is arranged between the tapered surface 10c of the static sealing ring 10 and the hook-shaped portion 14b of the holder 14.

When the static sealing ring 10 is attached to the retainer 5A and the holder 14, the static sealing ring 10 is arranged on the outer peripheral surface of the extending portion 52 of the retainer 5A, and then between the holder 14 and the tapered surface 10c of the static sealing ring 10. The holder 14 is fixed to the flange portion 53 of the retainer 5A by the socket bolt 16 with the O-ring 34 arranged in the holder. Since the static sealing ring 10 is composed of the divided bodies 10a and 10b as described above, it can be attached to the outer peripheral surface of the extending portion 52 from the outer diameter side, and the attaching work is simplified.

When the socket bolt 16 is tightened, the holder 14 approaches the flange portion 53 of the retainer 5A in the axial direction, and the O-ring 34 presses the tapered surface 10c of the static sealing ring 10 inward in the axial direction. When the holder 14 abuts on the flange portion 53 of the retainer 5A, the static sealing ring 10 abuts on the flange portion 53 of the retainer 5A, and the tapered surface 10c is inclined so as to gradually increase in diameter toward the inside of the axial machine. Therefore, the pressing force in the axial direction machine transmitted to the static sealing ring 10 via the O-ring 34 is converted into the pressing force in the inner diameter direction by the tapered surface 10c (see the black dashed arrow in FIG. 2), and the static sealing is performed. By pressing the divided surfaces 11 and 11 of the divided bodies 10a and 10b constituting the ring 10 in the circumferential direction while being abutted against each other, the sealing property between the divided surfaces 11 and 11 is improved (FIG. 2 enlarged portion). See the white arrow in). This prevents the fluid to be sealed from leaking from between the divided surfaces 11 and 11. Further, the O-ring 33 prevents the fluid to be sealed from leaking from the gap between the extending portion 52 of the retainer 5A and the static sealing ring 10.

The O-ring 33 is fitted in a fitting recess 40 formed between the static sealing ring 10 and the extending portion 52. As shown in FIG. 4, the fitting recess 40 has a stepped portion 41 provided on the outer peripheral peripheral edge of the machine outside of the static sealing ring 10 and a stepped portion provided on the outer peripheral edge of the machine outside of the extending portion 52 of the retainer 5A. It is composed of 42 and 42, and is formed in a rectangular cross section that opens toward the outside of the machine in the axial direction.

The step portion 41 is a horizontal surface 10f extending in the axial direction from the end surface 10e on the outer side of the machine of the static sealing ring 10 toward the inside of the machine, a vertical surface 10g extending in the inner diameter direction from the inner end of the horizontal plane 10f, and a vertical surface 10g. It is composed of a contact surface 10h extending axially from the inner diameter side end portion to the inside of the machine and abutting on the extending portion 52, and is formed so as to be open to the outside of the machine in the axial direction and in the inner diameter direction.

The stepped portion 42 has a horizontal surface 52b extending axially from the outer end surface 52a of the extending portion 52 toward the inside of the machine, a vertical surface 52c extending in the outer radial direction from the inner end of the horizontal surface 52b, and a vertical surface 52c. It is composed of a contact surface 52d that extends axially from the outer diameter side end of the machine to the inside of the machine and abuts on the contact surface 10h, and is formed so as to be open on the outside of the machine in the axial direction and in the outer diameter direction. .. Further, the radial dimension L1 of the vertical surface 10g of the step portion 41 is formed to be longer than the radial dimension L2 of the vertical surface 52c of the step portion 42 (L1> L2).

The step portion 41 and the step portion 42 are formed in a notched shape by machining, molding, casting, or the like.

The O-ring 33 is an O-ring having an O-shaped cross-sectional view, and is in contact with the peripheral surface (horizontal plane 10f and horizontal plane 52b) of the fitting recess 40 and the inner bottom surface (vertical surface 10g and vertical surface 52c) of the fitting recess 40. is doing. Specifically, as described above, since the radial dimension L1 of the vertical surface 10g of the step portion 41 is formed to be longer than the radial dimension L2 of the vertical surface 52c of the step portion 42, the contact surface is formed. The 10h and the contact surface 52d are arranged closer to the inner diameter side on the inner bottom surface of the fitting recess 40, and the O-ring 33 is a vertical surface 10g (contact surface 10h and contact surface) on the bottom surface of the fitting recess 40. It is in contact with the outer diameter side of 10h). Hereinafter, for convenience of explanation, the contact portion between the O-ring 33 and the vertical surface 10 g is the contact portion PT1 (seal surface), and the contact portion between the O-ring 33 and the horizontal plane 52b is the contact portion PT2 (seal surface) and the O-ring 33. The contact portion between the surface and the horizontal plane 10f will be described as a contact portion PT3 (seal surface).

Further, in the O-ring 33, the half surface 33a (the left half surface of the paper surface) on the outer side of the axial machine is exposed to the sealed fluid side H through the opening of the fitting recess 40 (outside the axial machine) in the cross-sectional view. That is, the half surface 33a of the O-ring 33 functions as a pressure receiving surface that receives the pressure P1 (black arrow in FIG. 4) from the sealed fluid, and the O-ring 33 is compressed by the pressure P1. Therefore, since the O-ring 33 receives the pressure P1 from the sealed fluid in addition to the elastic repulsive force to the contact portions PT1, PT2, and PT3 generated at the time of installation in the fitting recess 40, the pressing force P2 to the contact portion PT1 is received. , And the pressing force P3 on the contact portions PT2 and PT3 is generated, and the sealing property of the gap between the contact surface 10h and the contact surface 10h is improved. The elasticity of the O-ring 33 may be deformable by the pressure of the fluid to be sealed, and may be more easily elastically deformed than the statically sealed ring 10.

As shown in FIG. 5, when the static sealing ring 10 is tilted with respect to the retainer 5A due to vibration of the rotating shaft 3 during operation, pressure fluctuation of the sealed fluid, temperature change, etc., the O-ring 33 of this embodiment is used. The O-ring 33 is deformed and follows the contact portions PT1, PT2, and PT3 due to the pressure P1 from the sealed fluid on the outer half surface 33a of the cross-sectional axial direction machine. The pressing pressures P2 and P3 can maintain the contact portions PT1, PT2 and PT3 between the O-ring 33 and the vertical surface 10 g, the horizontal plane 10f and the horizontal plane 52b, and maintain the sealing property between the O-ring 33 and the fitting recess 40. Dripping.

Therefore, it is possible to prevent the sealed fluid from entering the gap between the contact surface 10h and the contact surface 10h without using the O-ring 33 having a high elastic rebound force. In particular, in the outside type mechanical seal 1 as in this embodiment, since it is difficult for the sealed fluid to enter the gap between the contact surface 10h and the contact surface 10h, the pressure of the sealed fluid is that of the divided bodies 10a and 10b. It is possible to suppress the action of the divided surfaces 11 and 11 in the opening direction, and the sealing function of the divided surfaces 11 and 11 can be fully exerted. Further, by using an inexpensive O-ring 33 having a relatively low elastic rebound force, the assembly work of the mechanical seal 1 is easy, and the O-ring 33 can be greatly compressed in the radial direction (not bulky in the radial direction). , The structure of the mechanical seal 1 can be made compact. Note that FIG. 5 illustrates a state in which the rest-sealing ring 10 is tilted more than the actual retainer 5A for the sake of easy understanding.

Further, the extending portion 52 of the retainer 5A is located at a position close to the sliding surface S between the static sealing ring 10 and the rotary sealing ring 20 (at the outer end of the static sealing ring 10 which is the base end of the convex portion 10d). Since the O-ring 33 is arranged on the tip side (outside of the machine) on the outer peripheral surface of the extension portion 52, it is possible to seal most of the divided surfaces 11 and 11 in the axial direction. , It is difficult for the sealed fluid to flow into the divided surfaces 11 and 11.

The tip end side of the retainer refers to the other retainer side facing the axial center of the axially extending portion (extending portion) of one retainer, and the position where the secondary seal is attached is the tip of the retainer. The closer to the side (position closer to the sliding surface S), the better the sealing property of the divided surface, which is preferable.

Further, since the contact portion PT1 that contacts the vertical surface 10g of the fitting recess 40 is provided inside the axial machine of the O-ring 33, when the half surface 33a of the O-ring 33 receives the pressure of the sealed fluid. The O-ring 33 is easily deformed so as to bulge in the radial direction, and the sealing properties of the contact portions PT1, PT2, and PT3 can be improved. Further, since the pressure receiving surface of the O-ring 33 is the half surface 33a on the outer side of the cross-sectional axial direction machine in the O-ring 33, the pressure of the fluid to be sealed can be widely received.

Further, since the O-ring 33 is arranged in the fitting recess 40 formed by the static sealing ring 10 and the retainer 5A, the installation position of the O-ring 33 can be stabilized (difficult to come off). Further, since the O-ring 33 can be installed in the axial direction from the opening of the fitting recess 40, the fitting recess is compared with the conventional mode in which the diameter of the O-ring 33 is expanded and the O-ring 33 is mounted from the outer diameter direction. The work of attaching the O-ring 33 to the 40 is simple. Further, the fitting portion (contact portion PT1, PT2, PT3) of the O-ring 33 fitted in the fitting recess 40 is used as a sealing surface, and a half surface of the O-ring 33 located at the opening of the fitting recess 40. 33a can be configured as a pressure receiving surface.

Further, since the fitting recess 40 is configured by joining the step portion 41 of the static sealing ring 10 and the step portion 42 of the retainer 5A, the fitting recess 40 can be easily configured and the static sealing to be sealed is desired. The joint surface (contact surface 10h and contact surface 10h) between the ring 10 and the retainer 5A can be arranged closer to the radial center of the inner bottom surface (vertical surface 10g, 52c) of the fitting recess 40. According to this, even if a small amount of the fluid to be sealed leaks from the O-ring 33 due to aging or the like, it is blocked by the step portion 41 (vertical surface 10 g) and the step portion 42 (vertical surface 52c), so that the leaked sealed fluid is sealed. It is possible to prevent the fluid from directly entering the sealed fluid between the contact surface 10h and the contact surface 10h.

Further, since the O-ring 33 has an O-shaped cross-sectional view, it can be deformed with a uniform force regardless of which portion receives an external force. Further, since the radial dimension L1 of the vertical surface 10g of the step portion 41 is formed to be longer than the radial dimension L2 of the vertical surface 52c of the step portion 42, the contact surface 10h and the contact surface 10h are formed. Is arranged closer to the inner diameter side on the bottom surface of the fitting recess 40, and the O-ring 33 is placed on the vertical surface 10g (the outer diameter side of the contact surface 10h and the contact surface 10h) on the bottom surface of the fitting recess 40. Are in contact. According to this, it is possible to prevent the sealing surface (contact portion PT1) of the O-ring 33 from coming into contact with the joint portion (between the contact surface 10h and the contact surface 10h) between the static sealing ring 10 and the retainer 5A. That is, it is possible to prevent problems such as the O-ring 33 getting into the space between the contact surface 10h and the contact surface 10h due to its deformation.

The radial dimension of the vertical surface 10g of the step portion 41 is formed shorter than the radial dimension of the vertical surface 52c of the step portion 42, and the O-ring 33 is formed on the vertical surface 52c at the bottom surface of the fitting recess 40. They may come into contact with each other, and even in this case, the same effect as described above can be exhibited.

Further, both the static sealing ring 10 and the rotary sealing ring 20 are split type sealing rings divided in the circumferential direction, and the O-ring 33 and the O-ring 36 are included in both the static sealing ring 10 and the rotary sealing ring 20. Is provided. According to this, since both the static sealing ring 10 and the rotary sealing ring 20 are divided in the circumferential direction, the installation work of the static sealing ring 10 and the rotary sealing ring 20 is easy, and the O-ring 33 and the O-ring 36 are used. Both the static sealing ring 10 and the rotary sealing ring 20 can enhance the sealing property.

Further, as shown in FIG. 3, the pressure receiving surface (half surface 33a) of the O-ring 33 and the pressure receiving surface of the O-ring 36 face each other in the axial direction of the rotating shaft 3. According to this, since the pressure receiving surface of the O-ring 33 on the static sealing ring 10 side and the pressure receiving surface of the O-ring 36 on the rotary sealing ring 20 side face each other via the sealed fluid, the pressure receiving surface between these pressure receiving surfaces ( The pressure of the sealed fluid intervening in the predetermined area) can be evenly received.

Further, as a modification 1 of the fitting recess, there is also the following. As shown in FIG. 6, the fitting recess 401 of the modified example 1 is composed of a step portion 41 of the static sealing ring 10 and an extension portion 521 of the retainer 50A. The extending portion 521 has a flat ring shape without a stepped portion. Even with such a shape, since the half surface 33a of the O-ring 33 is exposed to the sealed fluid side H, the pressure of the sealed fluid is used to be used between the O-ring 33 and the fitting recess 401. Sealing property is maintained.

Further, as a modification 2 of the fitting recess, the following is also available. As shown in FIG. 7, in the static sealing ring 100 of the present modification 2, the convex portion 100d is arranged so as to be closer to the inner diameter side of the machine outer end surface 100a. Further, the machine outer end surface 522a of the extension portion 522 of the retainer 500A is arranged outside the machine in the axial direction with respect to the machine outer end surface 100a of the static sealing ring 100, and the sliding surface S of the static sealing ring 100 (convex portion 100d). It is located slightly inside the machine in the axial direction. The fitting recess 402 is formed by cutting out the outer peripheral edge of the machine outside of the convex portion 100d and the outer peripheral edge of the machine outside of the extending portion 522 in the circumferential direction. Further, the left end of the O-ring 33 in the axial direction is arranged at a position where it overlaps with the outer end surface 522a of the retainer 500A in the radial direction. That is, as compared with the first embodiment, the fitting recess 402 and the O-ring 33 can be arranged at positions closer to the sliding surface S in the axial and radial directions, so that the sealing property of the divided surface of the static sealing ring 100 is improved. do. In addition, it may be arranged in a position close to the axial direction or the radial direction.

Although examples of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these examples, and any changes or additions that do not deviate from the gist of the present invention are included in the present invention. Will be.

For example, in the above embodiment, the fitting recess in which at least three surfaces are surrounded has been described, but the present invention is not limited to this. It may be held by the elastic holding force of the next seal.

Further, in the above embodiment, the outside type mechanical seal has been described, but the present invention is not limited to this, and is an inside type mechanical seal that seals the sealed fluid that tends to leak from the outer peripheral side to the inner peripheral side. May be good.

Further, in the above embodiment, the embodiment in which the cross-sectional view O-type O-ring is used as the secondary seal is exemplified, but the present invention is not limited to this, and the cross-sectional view rectangular shape, the cross-sectional view polygonal shape, the cross-sectional view X-type, and the like are secondary. A seal may be used.

Further, the secondary seal is not limited to forming an annular shape in the natural state, and if it is continuous in the circumferential direction in the state of being attached between the seal ring and the retainer, it is divided in the circumferential direction in the natural state. May be good. Even if the secondary seal is divided in the circumferential direction in the natural state, the divided members constituting the secondary seal can be brought into close contact with each other due to the pressure of the fluid to be sealed to maintain the sealing property. Further, since the fitting recess is open in the axial direction, it is easy to attach the secondary seal having the split structure to the fitting recess.

Further, in the above embodiment, both the static sealing ring 10 and the rotary sealing ring 20 have a structure that is divided in the circumferential direction, but at least one of the sealing rings may have a divided structure. ..

1 Split type mechanical seal 2 Housing 3 Rotating shaft 5A, 5B Retainer 10 Static sealing ring 10a, 10b Split body 11 Split surface 20 Rotating sealing ring 33 O-ring (secondary seal)
33a Half side (pressure receiving side)
36 O-ring (secondary seal)
40 Fitting recess 41, 42 Step 50A Retainer 100 Static sealing ring 401,402 Fitting recess 500A Retainer H Sealed fluid side L Low pressure fluid side P1 Pressure P2, P3 Pushing pressure PT1, PT1'Contact part PT2, PT2' Contact Part PT3, PT3'Contact part PT4 Contact part S Sliding surface

Claims (5)

A static sealing ring and a rotary sealing ring, one of which is divided in the circumferential direction ,
A retainer for holding the split-type sealing ring from the radial direction on the sealed fluid side is provided.
In a split type mechanical seal in which the static sealing ring, the rotary sealing ring, and the retainer are integrated by a set bolt and mounted on an apparatus.
A secondary seal having an elastic secondary seal having a sealing surface in which the split-type sealing ring and the retainer are in contact with each other in the circumferential direction and a pressure receiving surface exposed toward the sealed fluid is provided.
The split-type sealing ring and the retainer form a fitting recess that opens axially toward the sealed fluid and into which the secondary seal is fitted.
The sealing surface of the secondary seal is in contact with the sealing ring or the retainer constituting the inner bottom surface of the fitting recess.
The mechanical seal is an outside type mechanical seal that seals the sealed fluid on the inner peripheral side of the static sealing ring and the rotary sealing ring.
The fitting recess is formed on the side opposite to the pressure receiving surface and is composed of at least one of the sealing ring and the retainer. The inner bottom surface is connected to the inner bottom surface and extends toward the pressure receiving surface side in the axial direction. It is formed from a surface and a sealed ring-side axial surface that is connected to the inner bottom surface and extends toward the axial pressure receiving surface side, and is axially opened on the opposite side of the inner bottom surface.
The secondary seal is a split type mechanical seal that is in contact with the retainer side axial surface, the sealing ring side axial surface, and the inner bottom surface over the entire circumferential direction . The split type mechanical seal according to claim 1 , wherein the fitting recess is formed by joining a step portion formed on the sealing ring and a step portion formed on the retainer. The split-type mechanical seal according to claim 1 or 2 , wherein the secondary seal is composed of an O-ring having an O-type in cross section . Both the static sealing ring and the rotary sealing ring are divided type sealing rings divided in the circumferential direction, and the secondary seal is provided on both the static sealing ring and the rotary sealing ring. The split type mechanical seal according to any one of claims 1 to 3 . A claim that the pressure receiving surface of the secondary seal provided on the static sealing ring and the pressure receiving surface of the secondary seal provided on the rotary sealing ring face each other in the axial direction of the rotating shaft. The split type mechanical seal according to any one of 1 to 4 .

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