JP4227116B2 - Split type mechanical seal - Google Patents

Description

  The present invention is an inner peripheral region of the relative rotational sliding contact portion of the sealing end surface, which is the opposing end surface of the first sealing ring on the seal case side and the second sealing ring on the rotary shaft side, due to the relative rotational sliding contact action. A mechanical seal configured to shield and seal a sealed fluid region and a non-sealed fluid region which is an outer peripheral side region, and in particular, the first sealing ring is divided in the circumferential direction and the divided surfaces collide with each other. The present invention relates to a split type mechanical seal that is internally fitted and held in a retainer in an annular form.

  As a conventional split-type mechanical seal, a split-type first seal ring held in a seal case via a metal retainer so as to be movable in the axial direction, and a non-split-type second seal ring fixed to a rotary shaft And a spring interposed between the seal case and the retainer to urge the retainer in the axial direction so as to press-contact the first seal ring against the second seal ring, The sealed end surface is a relative rotational sliding contact action, and is configured to shield and seal the sealed fluid region that is the inner peripheral region and the non-sealed fluid region that is the outer peripheral region of the relative rotational sliding contact portion. (Divided outside mechanical seal) is well known (for example, see FIG. 2 of Patent Document 1).

  Thus, in such a conventional divided mechanical seal, the first sealing ring is divided into a plurality of arc-shaped segments by dividing the first sealing ring in the circumferential direction, and the cylindrical first held by the seal case. A retainer member and an annular second retainer member that is attached to the retainer member so as to be tightened in the axial direction and holds the first sealing ring therein, and a second retainer member and the first sealing ring that fits inside the second retainer member And a cam surface that is a truncated conical surface that gradually increases in diameter in the tightening direction of the second retainer member to the first retainer member. Therefore, by tightening the second retainer member to the first retainer member and applying a tightening force in the diameter reducing direction to the first seal ring by the cam surface, the end surfaces of the arc-shaped segments are brought into contact with each other. It can be held tightly in the annular form to match (see, for example, FIGS. 2 and 4 of Patent Document 1).

  By the way, in the split mechanical seal, the first sealing ring is made of a material having a higher degree of wear than the second sealing ring (generally, the second sealing ring is made of a hard material such as ceramics, and the first sealing ring In this case, only the first seal ring is worn by sliding movement of both seal rings, and the sealing function is deteriorated due to wear of the seal rings. Only the first sealing ring needs to be replaced without disassembling the entire mechanical seal, maintenance is easy, and it is suitable as a shaft sealing means such as a large vertical pump.

JP 2004-251376 A

  In the above-described conventional split-type mechanical seal (hereinafter referred to as “conventional mechanical seal”), the first sealing ring is bound to an annular shape by a metal retainer (second retainer member). Combined with the fact that the ring is made of a soft material such as carbon as described above, the arc-shaped segment is deformed by the binding force of the cam surface, and the sealing end surface of the first sealing ring is distorted, resulting in the second The sealing function due to the relative rotational sliding contact with the sealing ring is not properly exhibited. When the tightening force due to the cam surface is low enough not to cause distortion on the sealed end surface, the arc-shaped segment of the arc-shaped segment is caused by the pressure of the sealed fluid that acts on the inner circumferential surface of the first sealing ring in the diameter expanding direction. The space between the abutting surfaces is opened, and the sealed fluid leaks from there, and naturally, a good sealing function cannot be exhibited.

  Therefore, in general, at the time of assembling the mechanical seal or performing maintenance for disassembling or replacing the first sealing ring, the sealing end surface of the first sealing ring is corrected by a so-called sliding operation, or the radial width of the sealing end surface is increased. It is set to be extremely small, and so-called familiar operation is performed prior to regular operation.

  However, such a rubbing operation and a familiar operation are difficult to perform on the user side because it requires a high degree of skill, and it imposes an excessive burden on the operator, and the economic burden is extremely large. . In addition, the split type mechanical seal with an extremely small radial width of the shaft seal sealing end face is difficult to perform familiar operation under dry conditions. It cannot be employed as a shaft sealing means such as a pump, and its application is greatly limited.

  The present invention has been made in view of these points, and does not require a rubbing operation or a familiar operation, and binds a split-type sealing ring to an appropriate annular shape without causing distortion at its sealing end face. An object of the present invention is to provide a split-type mechanical seal that can be held.

  In the present invention, the first seal ring is divided into the circumferential direction and the retainer is fitted and held in an annular shape in which the divided surfaces abut each other, and at the opposing end surfaces of the first seal ring and the second seal ring, A split type configured to shield and seal a sealed fluid region which is an inner peripheral side region and an unsealed fluid region which is an outer peripheral side region by a relative rotational sliding contact action of a certain sealing end surface. In the mechanical seal, in order to achieve the above object, in particular, the first sealing ring is tightly held in an annular shape by the elastic force of an elastic material binding body loaded between the opposed peripheral surfaces of the first sealing ring and the retainer. It is suggested to keep.

  In a preferred embodiment of such a split type mechanical seal, a retainer is attached to a cylindrical first retainer member held by a seal case, and can be fastened in an axial direction to hold the first sealing ring. An annular holding surface and a first sealing member for holding the proximal end surface (back surface) of the first sealing ring in a secondary seal state on the distal end surface of the first retainer member. An annular pressing surface located in an annular loading space formed between the opposed peripheral surfaces of the ring and the second retainer member is formed, and the inner circumferential surface of the second retainer member has the pressing force in the loading space. An annular locking surface facing the surface is formed, and the binding body is loaded in the loading space in a state where the binding body is clamped between the pressing surface and the locking surface. In such an embodiment, at least one of the pressing surface and the locking surface is configured as a cam surface which is a truncated conical surface whose diameter gradually decreases in a direction away from the pressing surface or the locking surface as a mating surface. Preferably it is. The first retainer member is an annular portion having a cylindrical main body portion held by the seal case and to which the second retainer member is attached, and the holding surface and the pressing surface, and is relatively moved in the axial direction to the main body portion. The sealing ring holding part is configured to be separated from the inner ring so that the sealing ring holding part can be pressed into the sealing ring holding part by the pressure of the sealed fluid that enters between the opposing end surfaces of the main body part and the sealing ring holding part in the axial direction. It is preferable that an axial force that relatively displaces the surface in the direction to bring the surface close to the locking surface is applied. The binding body is preferably made of an incompressible elastic material (rubber or the like). Further, the binding body can be constituted by a plurality of elastic members arranged in parallel in the axial direction of the first sealing ring. In the present invention, the “axis” refers to a rotating shaft of a rotating device in which the split mechanical seal is incorporated, a second seal ring that is concentrically attached thereto, and a first seal ring that is concentrically opposed to the second seal ring. The “axis direction” means a direction parallel to the axis.

  In the split type mechanical seal of the present invention, the first sealing ring is tightly held in an annular shape by the elastic force of the elastic material binding body loaded between the opposed peripheral surfaces of the first sealing ring and the retainer. Therefore, unlike the conventional mechanical seal that is directly bound by the retainer, the divided surfaces of the first sealing ring can be properly abutted without causing distortion in the first sealing ring. Therefore, according to the split-type mechanical seal of the present invention, it is possible to easily and efficiently perform maintenance including assembly of the mechanical seal and disassembly and replacement of the first seal ring without requiring the sliding operation and the familiar operation described at the beginning. Can be done economically.

  Further, according to the split type mechanical seal of the present invention, the first retainer member is separated into the main body portion and the sealing ring holding portion, and the shaft in the direction toward the second sealing ring is formed in the sealing ring holding portion by the sealed fluid. By devising such that the directional thrust acts, the binding force is automatically adjusted according to the pressure of the fluid to be sealed, and a good sealing function can be exhibited regardless of the sealing conditions.

  1, 2 and 5 show a first embodiment of a split mechanical seal according to the present invention, and FIGS. 3 to 5 show a second embodiment of the split mechanical seal according to the present invention. Each embodiment relates to an example in which the present invention is applied to the shaft sealing means of the preceding standby type pump shown in FIG. 7 or FIG. In the following description, the split mechanical seal in the first embodiment is referred to as a first mechanical seal M1, and the split mechanical seal in the second embodiment is referred to as a second mechanical seal M2.

  The preceding standby pump 1 shown in FIG. 7 and FIG. 8 is a vertical shaft diagonal flow pump such as an irrigation pump that is operated in advance standby, and has a discharge elbow (discharge port) 2a and a suction bell (suction port) 2b at the upper and lower ends. The pump casing 2 that is long in the up-down direction, and extends upward from the vicinity of the suction bell 2b through the center of the pump casing 2 and is connected to the prime mover 3 installed in the upper portion of the pump casing 2. The pump shaft 4 and the impeller 5 provided at the lower end portion of the pump shaft 4 in the vicinity of the upper portion of the suction bell 2b are provided, and are the peripheral wall portion of the discharge elbow 2a. As a shaft sealing means for sealing between the cylindrical shaft sealing portion 2c through which the pump penetrates and the pump shaft 4, the first mechanical seal M1 is used as shown in FIG. 7, or the second mechanical seal M2 as shown in FIG. using That. In addition, each mechanical seal structural member in the following description shows the structural member of both seal | stickers M1 and M2, unless otherwise specified.

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Thus, as shown in FIG. 1 or FIG. 3, each seal M1, M2 includes a seal case 6 attached to a shaft seal portion 2c which is a rotating shaft penetrating portion of the pump casing 2, and a retainer 7 and a binding to the seal case 6. A first sealing ring 9 that is movable in the axial direction (vertical direction) through the body 8 and is held so as not to rotate relative to it, and a pump shaft 4 that is disposed above the first sealing ring 9 and that is a rotating shaft is fixed. A second seal ring 10 and a spring 11 interposed between the seal case 6 and the retainer 7 and biasing the first seal ring 9 upward to press-contact the second seal ring 10 against the second seal ring 10. Then, due to the relative rotational sliding contact action of the sealing end faces 9a, 10a which are the opposed end faces of the both sealing rings 9, 10, a sealed fluid region (pump casing 2) which is an inner peripheral side region of the relative rotational sliding contact portions 9a, 10a. (Communication area) S and its outer peripheral side area It is a non-sealed fluid region of the configured end face contact to shield seal and A (atmospheric region outside the pump casing 2) split outside mechanical seal is.

  As shown in FIG. 1 or FIG. 3, the seal case 6 is an annular body having an L-shaped cross section having an inner peripheral portion having a diameter larger than that of the pump shaft 4. It is attached via an O-ring 12 to the upper end of the sealing part 2c.

  As shown in FIG. 5, the first sealing ring 9 is an annular body having a sealing end surface 9a as a front end surface, and is divided into a plurality (two in this example) arc-shaped segments 13 and 14 in the circumferential direction. The split surfaces (circumferential end surfaces of the arc-shaped segments 13 and 14) 13a and 14a are abutted and held in a retainer 7 (second retainer member 25) to be described later.

  As shown in FIG. 1 or FIG. 3, the second sealing ring 10 is an annular body having a non-divided structure, and is fixedly held on the pump shaft 4 via a fixing ring 15 and a holding ring 16. That is, the fixing ring 15 is divided into two in the circumferential direction, and is fitted and fixed to the pump shaft 4 by being fastened in a ring shape with the fastening bolts 17. The holding ring 16 is fixed to the pump shaft 4 by being inserted into and held by the pump shaft 4 through an O-ring 18 and connected to the fixing ring 15 by a connecting bolt 19 below the fixing ring 15. The second sealing ring 10 is fitted and held via the O-rings 20 and 21 in the annular recess 16a formed at the lower end portion of the holding ring 16, and the engagement pin 22 provided on the holding ring 16 is engaged. The pump shaft 4 is fixedly held. The second seal ring 10 is made of a hard material such as ceramics, and the first seal ring 9 is softer than the material having a higher degree of wear than the second seal ring 10, for example, the constituent material of the second seal ring 10 and is self-supporting. It is composed of carbon having lubricity.

  As shown in FIG. 1 or FIG. 3, the retainer 7 is attached to the metal first retainer member 24 held by the seal case 6 and the first retainer ring 24 so as to be clamped in the axial direction, and holds the first sealing ring 9 inside. The second retainer member 25 is made of metal.

  As shown in FIG. 1, the first retainer member 24 in the first mechanical seal M <b> 1 has a cylindrical shape that is held in the seal case 6 via an O-ring 26 so as to be movable in the axial direction. Relative rotation of the first retainer member 24 with respect to the seal case 6 is prevented by the engaging action of the drive pin 6 a protruding from the seal case 6. The front end surface (upper end surface) 24 a of the first retainer member 24 has a rear surface (lower end surface) 9 b that is the base end surface of the first sealing ring 9 through the O-ring 27 in a secondary sealed state. And the annular | circular shaped press surface 24c located in the cyclic | annular loading space 28 formed between the opposing peripheral surfaces 9c and 25a of the 1st sealing ring 9 and the 2nd retainer member 25 is formed. As shown in FIG. 2, an annular convex portion 24d that can be projected and retracted in the loading space 28 in the axial direction protrudes from the distal end surface 24a of the first retainer member 24. An end surface (upper surface) of the annular convex portion 24d is provided. The end surface is a pressing surface 24c. Further, by engaging a locking pin 29 protruding from the front end surface 24a of the first retainer member 24 with a recess formed on the back surface 9b of the first sealing ring 9, relative rotation of both the members 9 and 24 is prevented. Yes.

  As shown in FIG. 3, the first retainer member 24 in the second mechanical seal M <b> 2 has a first sealing ring 9 on the front end surfaces (upper end surfaces) 24 a and 24 e in the same manner as the first retainer member 24 in the first mechanical seal M <b> 1. The back surface 9b of the first sealing ring 9 and the second retainer member 25 are formed between a holding surface 24b for abutting and holding the back surface 9b through an O-ring 27 in a secondary sealed state, and an annular shape formed between the opposing peripheral surfaces 9c and 25a. Although it has a cylindrical shape formed with an annular pressing surface 24c located in the loading space 28, the main body portion 24A and the sealing ring holding portion 24B are separated as follows. That is, as shown in FIG. 3, the main body portion 24A has a cylindrical shape that is fitted and held in the seal case 6 through an O-ring 26 so as to be movable in the axial direction, and to which a second retainer member 25 described later is attached. 3 and 4, an annular recess 24f for fitting and holding the sealing ring holding portion 24B is formed on the inner peripheral side portion of the upper end surface portion 24a. As shown in FIG. 4, the sealing ring holding portion 24B is an annular body in which a pressing surface 24c and a holding surface 24b are formed on the upper end surface portion 24e, and is fitted and held in an annular recess 24f of the main body portion 24A so as to be movable in the axial direction. ing. In the fitting portion between the main body portion 24A and the sealing ring holding portion 24B, an O-ring 30 is mounted between the opposed peripheral surfaces of both portions 24A and 24B so as to be secondary-sealed in a state in which they can move relative to each other in the axial direction. At the same time, the sealed fluid can enter between the opposed end faces 24g and 24h of the two parts 24A and 24B in the axial direction. Both portions 24A and 24B are allowed to move relative to each other in the axial direction by engaging a locking pin 31 protruding from the main body portion 24A with a recess formed in a base end surface (lower end surface) 24h of the sealing ring holding portion 24B. Relative rotation is blocked in As shown in FIG. 4, an annular convex portion 24 d that can be projected and retracted in the loading space 28 in the axial direction protrudes from the end surface portion 24 e of the sealing ring holding portion 24 </ b> B. The end surface is a pressing surface 24c. Further, by engaging the locking pin 29 protruding from the end surface portion 24e of the sealing ring holding portion 24B with the concave portion formed on the back surface 9b of the first sealing ring 9, relative rotation of the both 9 and 24 is prevented. Yes.

  As shown in FIG. 1 or FIG. 3, the second retainer member 25 is an annular body having an inner peripheral surface 25 a larger in diameter than the outer diameter of the first sealing ring 9, and is The retainer member 24 (a main body portion 24A in the case of the second mechanical seal M2) is attached so as to be clamped in the axial direction. On the inner peripheral surface 25a of the second retainer member 25, an annular locking surface 25b formed on the first retainer member 24 (or the main body portion 24A in the case of the second mechanical seal M2) is opposed to the pressing surface 24c in the axial direction. Is formed. The locking surface 25b is configured as a cam surface that is a truncated conical surface that gradually decreases in diameter in a direction away from the pressing surface 24c.

  The binding body 8 is an annular member made of an incompressible elastic material such as rubber or synthetic resin, as shown in FIG. 1 or FIG. 3, and the loading space 28 is provided between the pressing surface 24c and the locking surface 25b. As shown in FIG. 5, the first sealing ring 9 is tightly bound to an annular shape in which the end faces 13a and 14a of the arc-shaped segments 13 and 14 abut with each other by its elastic force. ing. In the first mechanical seal M1, the binding body 8 is configured by a single annular member, and in the second mechanical seal M2, the binding body 8 is configured by a plurality of annular members 8a. That is, in the first mechanical seal M1, as shown in FIGS. 1 and 2, as the binding body 8, the opposed peripheral surfaces 9c and 25a of the first sealing ring 9 and the second retainer member 25, the pressing surface 24c, and the locking One annular elastic member formed into a cross-sectional shape corresponding to the space shape surrounded by the surface 25b or one annular elastic member that can be compressed and deformed into the cross-sectional shape is used. Further, in the second mechanical seal M1, as shown in FIGS. 3 and 4, a plurality of (three in the illustrated example) annular elastic members (for example, an O-ring or the like) are arranged in parallel in the axial direction as the binding body 8. A similar annular elastic ring) 8a is used, and these elastic members 8a are compressed and deformed so as to have the cross-sectional shape as a whole.

  In the first or second mechanical seal M1, M2 configured as described above, the second retainer member 25 is replaced with the first retainer member 24 (the main body of the first retainer member 24 in the second mechanical seal M2). When the fastening bolt 32 attached to the portion 24A) is tightened, the pressing surface 24c and the locking surface 25b are relatively displaced in the proximity direction, and the binding body 8 (in the second mechanical seal M2) loaded in the loading space 28 is provided. The elastic member group 8a) is compressed and deformed in the axial direction, and the pressure contact force to the outer peripheral surface 9c of the first seal ring 9 in the radial direction increases, so that the first seal ring 9 is connected to the binding body 8 or the elastic member group 8a. Bound by elastic force.

  Therefore, by adjusting the tightening amount of the tightening bolt 32, the first sealing ring 9 is tightly held in an annular shape in which the end faces 13a, 14a of the arc-shaped segments 13, 14 are properly abutted. At this time, since the arc-shaped segments 13 and 14 are bound by the elastic force of the binding body 8 or the elastic member group 8a, they are directly bound by a metal retainer like the conventional mechanical seal described at the beginning. Unlike the case, the arc-shaped segments 13 and 14 are not deformed, and the sealing end face 9a of the first sealing ring 9 is not distorted.

  Further, by setting the locking surface 25b to be a tapered (truncated conical) cam surface as described above, the binding body 8 or the elastic member group 8a is compressed in the axial direction by the pressing surface 24c and the locking surface 25b. In this case, elastic deformation of the binding body 8 or the elastic member 8a in the inner peripheral direction can be promoted, and the first sealing ring 9 can be more effectively bound by the binding body 8 or the elastic member group 8a. .

  Further, in the second mechanical seal M2, as shown in FIG. 4, the sealed fluid enters between the opposed end surfaces 24g and 24h of the main body portion 24A of the first retainer member 24 and the sealing ring holding portion 24B, Due to the pressure (back pressure) P, an axial force that relatively displaces the pressing surface 24c toward the locking surface 25b acts on the sealing ring holding portion 24B, and the elastic member group 8a serving as the binding body 8 is axially moved. Will compress in the direction. The degree of compression of the elastic member group 8a by this axial force is proportional to the pressure P of the sealed fluid. Accordingly, a binding force of the first sealing ring 9 according to the pressure P of the fluid to be sealed is obtained, and the abutting force of the end faces 13a and 14a of the arc-shaped segments 13 and 14 is increased by the internal pressure (the first pressure of the first sealing ring 9). 1 and the pressure of the sealed fluid acting on the inner peripheral surface of the sealing ring 9). Regardless of the pressure conditions (pressure fluctuations, etc.) of the sealed fluid region S, the arcuate segments 13, 14 are always The end faces 13a and 14a will abut with an appropriate pressure, and the internal pressure of the first sealing ring 9 will cause the segment end faces 13a and 14a to open and leak, or conversely, the binding force of the first sealing ring 9 will be more than necessary. The distortion does not occur in the sealed end face 9a.

  Therefore, according to the first and second mechanical seals M1 and M2, assembly and maintenance of the mechanical seals M1 and M2 can be performed easily and economically without the need for the sliding operation and the familiar operation described at the beginning. The first sealing ring 9 can be tightly held in an appropriate annular form without causing distortion in the sealed end face 9a, and a good mechanical seal function can be exhibited.

  The present invention is not limited to the above-described embodiments, and can be appropriately improved and changed without departing from the basic principle of the present invention.

  For example, the binding body 8 may be composed of a single annular elastic member as shown in FIGS. 1 and 2, or a plurality of annular elastic members 8a as shown in FIGS. Further, one or a plurality of places in the circumferential direction may be separated. For example, the binding body 8 or each elastic member 8a is loaded into the loading space 28 by making a C-shaped member or a plurality of arc-shaped members separated from each other into an annular shape. As a constituent material of the binding body 8 or the elastic member 8a, it is preferable to use an incompressible elastic material such as rubber or synthetic resin. However, if the first sealing ring 9 can be bound by an elastic force, the incompressible material can be used. It is not limited to an elastic material.

  In the example described above, the locking surface 25b is configured as a truncated cone-shaped cam surface that gradually decreases in the direction away from the pressing surface 24c. Conversely, the pressing surface 24c is separated from the locking surface 25b. Even if it is configured as a truncated conical cam surface that gradually decreases in diameter in the direction, it is also possible to configure both the surfaces 24c and 25b as cam surfaces. Further, as shown in FIG. 6, neither the pressing surface 24c nor the locking surface 25b can be a cam surface, and can be a non-cam surface orthogonal to the axis.

  The present invention can also be applied to a split type mechanical seal in which the second seal ring 10 is divided like the first seal ring 9.

It is a vertical front view which shows a 1st mechanical seal. It is an enlarged view of the principal part of FIG. It is a vertical front view which shows a 2nd mechanical seal. It is an enlarged view of the principal part of FIG. FIG. 5 is a transverse plan view taken along line VV in FIG. 1 or FIG. 3. It is a vertical front view equivalent to FIG. 4 which shows the modification of a 2nd mechanical seal. It is a vertical front view which shows an example of the vertical axis mixed flow pump provided with the 1st mechanical seal. It is a vertical front view which shows an example of the vertical axis mixed flow pump provided with the 2nd mechanical seal.

Explanation of symbols

6 Seal Case 7 Retainer 8 Tightened Body 8a Elastic Member 9 First Seal Ring 9a Sealed End Surface of the First Seal Ring 9b Base End Surface (Back) of the First Seal Ring
9c Outer peripheral surface of first sealing ring 10 Second sealing ring 10a Sealing end surface of second sealing ring 24 First retainer member 24A Main body portion 24B Sealing ring holding portion 24c Pressing surface 24g Opposing end surface of main body portion and sealing ring holding portion 24h Opposing end face of main body part and sealing ring holding part 25 Second retainer member 25a Inner peripheral surface 25b of second retainer member A Locking surface A Non-sealed fluid region (atmospheric region)
M1 First mechanical seal M2 Second mechanical seal S Sealed fluid region

Claims (4)

The divided surface with the first seal ring of the seal case (6) side (9) is divided in the circumferential direction is fitted and held in the retainer (7) in an annular form in which abutting, the first seal ring ( 9) and the relative rotational sliding contact portion (9a, 10a) of the sealing end surface (9a, 10a) which is the opposing end surface of the second sealing ring (10 ) on the rotating shaft (4) side. In the split mechanical seal configured to shield and seal the sealed fluid region (S) that is the inner peripheral region and the non-sealed fluid region (A) that is the outer peripheral region,
The first sealing ring (9) is tightly held in an annular shape by the elastic force of the elastic material binding body (8) loaded between the opposed peripheral surfaces of the first sealing ring (9) and the retainer (7) .
A cylindrical first retainer member (24) having a retainer (7) held by a seal case (6) and an annular shape attached to the first retainer member (24) so as to be clamped in the axial direction and holding the first sealing ring (9) inside. Of the first retainer member (24), and the base end surface (9b) of the first seal ring (9) is abutted and held in a secondary seal state on the distal end surface of the first retainer member (24). An annular pressing surface (24c) located in the annular loading space (28) formed between the holding surface (24b) and the opposed peripheral surface of the first sealing ring (9) and the second retainer member (25). An annular locking surface (25b) is formed on the inner peripheral surface of the second retainer member (25) so as to face the pressing surface (24c) in the loading space (28). (8) pinched this between the pressing surface (24c) and the locking surface (25b) In state has been loaded into the loading space (28),
A cylindrical main body portion (24A) in which the first retainer member (24) is held by the seal case (6) and the second retainer member (25) is attached, the holding surface (24b) and the pressing surface (24c). And a sealing ring holding portion (24B) that is fitted and held in the main body portion (24A) so as to be relatively movable in the axial direction, and is separated from the main body portion (24A) in the axial direction. Due to the pressure of the sealed fluid that enters between the end faces (24g, 24h) facing the seal ring holding portion (24B), the pressing surface (24c) is close to the locking surface (25b) and the seal ring holding portion (24B). A split-type mechanical seal characterized in that an axial force for relative displacement in the direction to be applied acts . At least one of the pressing surface (24c) and the locking surface (25b) is a cam surface that is a truncated conical surface that gradually decreases in diameter in a direction away from the pressing surface (24c) or the locking surface (25b) as a mating surface. The split-type mechanical seal according to claim 1, which is configured . The split-type mechanical seal according to claim 1 or 2, wherein the binding body (8) is made of an incompressible elastic material . Bondage body (8), characterized in that it is constituted by a plurality of resilient members in parallel to the axial direction of the first seal ring (9) (8a), in claim 1, claim 2 or claim 3 Split type mechanical seal to be described.