JP2017207147A - mechanical seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical seal capable of inhibiting the flatness of a seal surface of a rotary seal ring from lowering and the squareness of the seal surface to a rotating shaft from being impaired.SOLUTION: A mechanical seal 1 comprises a retainer 6 that is installed in an integrally-rotatable manner to the side of a rotating shaft S passing through a casing C and is formed with an annular groove part 62 in one end face in the axial direction, and a rotary seal ring 7 that is fitted in the groove part 62 of the retainer 6 and has a seal surface 7a slidably contacting with a seal surface 3a of a stationary seal ring 3. The rotary seal ring 7 is loosely fitted in the groove part 62 with an annular first elastic member 31 interposed between a back face 7c of the seal surface 7a of the rotary seal ring and a bottom face 62a of the groove part 62 opposed to the back face 7c. The mechanical seal 1 further comprises a whirl-stop mechanism 40 for regulating rotation of the rotary seal ring 7 relative to the retainer 6.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a mechanical seal.

  Conventionally, as shown in FIG. 6, a stationary sealing ring 103 fixed to the casing 101 side and a rotating shaft 102 side are attached so as to be able to rotate integrally as a seal for the sealed fluid inside the rotary fluid device. There is known a mechanical seal that includes a rotary seal ring 104 and in which a seal surface 103a formed on the stationary seal ring 103 and a seal surface 104a formed on the rotary seal ring 104 are in sliding contact.

  In such a mechanical seal, a groove 105a is formed on one axial end surface of a retainer 105 that is externally fitted to the rotary shaft 102, and the rotary seal ring 104 is fixed to the groove 105a by shrink fitting. For this reason, the back surface 104b that is the opposite side of the seal surface 104a of the rotary seal ring 104 is in contact with the bottom surface 105b of the groove 105a (see, for example, Patent Document 1).

JP 2013-177914 A (see FIG. 4)

Since the rotary seal ring 104 of the mechanical seal is fixed to the groove portion 105a of the retainer 105 by shrink fitting, distortion is likely to occur on the seal surface 104a of the rotary seal ring 104 due to residual stress due to the shrink fit. As a result, the flatness of the seal surface 104a is adversely affected.
Further, since the back surface 104b of the rotary seal ring 104 is in metal contact with the bottom surface 105b of the groove 105a by shrink fitting, if the flatness of the back surface 104b is low, the flatness is corrected by the bottom surface 105b of the groove 105a. The rotation sealing ring 104 is easy to tilt with respect to the rotation shaft 102. As a result, the perpendicularity of the seal surface 104a with respect to the rotating shaft 102 is adversely affected.

As described above, in the mechanical seal, since the rotary seal ring 104 is fixed to the groove portion 105a by shrink fitting, the seal surface 104a is distorted to reduce the flatness of the seal surface 104a, Since the back surface 104b of the surface 104a is in metal contact with the groove portion 105a and the rotary seal ring 104 is inclined with respect to the rotary shaft 102, the perpendicularity of the seal surface 104a with respect to the rotary shaft 102 is impaired. There was a problem that decreased.
This invention is made | formed in view of such a situation, and it suppresses that the flatness of the sealing surface of a rotation sealing ring falls, or the perpendicularity with respect to the rotating shaft of the said sealing surface is impaired. An object of the present invention is to provide a mechanical seal that can be used.

  The mechanical seal of the present invention is attached to the casing side, and is attached to the stationary seal ring having a seal surface and the rotary shaft side penetrating the casing so as to be integrally rotatable, and an annular groove is formed on one end surface in the axial direction. A mechanical seal comprising: a retainer; and a rotary seal ring that is fitted in a groove portion of the retainer and has a seal surface that is in sliding contact with the seal surface of the stationary seal ring. An annular first elastic member is interposed between the back surface on the opposite side and the bottom surface of the groove portion facing the back surface, and the groove is loosely fitted into the groove portion, and the rotary sealing ring is attached to the retainer. An anti-rotation mechanism is provided that restricts rotation against the rotation.

  According to the mechanical seal configured as described above, since the rotary seal ring is loosely fitted into the groove portion of the retainer, it is possible to reduce the occurrence of residual stress in the rotary seal ring due to the fitting, and as a result, the rotary seal Generation of distortion on the seal surface of the ring can be suppressed. Further, since the first elastic member is interposed between the back surface of the rotary seal ring and the bottom surface of the groove portion, even if the flatness of the back surface is low, the flatness is corrected by the first elastic member. As a result, it is possible to suppress the sealing surface of the rotary seal ring from being inclined with respect to the rotation axis.

Therefore, the seal surface of the rotary seal ring is distorted and the flatness of the seal surface is reduced, or when the flatness of the back surface is low, the rotary seal ring is inclined and the perpendicularity of the seal surface to the rotation axis is impaired. Therefore, it is possible to suppress the deterioration of the sealing performance of the mechanical seal.
Further, since the mechanical seal has a detent mechanism for restricting the rotation sealing ring from rotating with respect to the retainer, the rotation sealing ring rotates with respect to the retainer even if the rotation sealing ring is loosely fitted into the retainer. Can be prevented.

It is preferable that an annular second elastic member is interposed between the outer peripheral surface of the rotary seal ring and the peripheral surface of the groove portion facing the outer peripheral surface.
In this case, even if the flatness of the outer peripheral surface of the rotary seal ring is low, the flatness can be corrected by the second elastic member. It is possible to further suppress adverse effects on the perpendicularity with respect to the rotation axis.

  It is preferable that a diamond film is formed on at least the sealing surface of the rotary seal ring. In this case, since the diamond film has a large thermal conductivity, the frictional heat generated on the sealing surface of the rotary seal ring can be efficiently released. Thereby, since it can suppress that a thermal strain generate | occur | produces on a sealing surface, it can further suppress that the flat surface of a sealing surface falls.

It is preferable that a tapered surface that gradually increases in diameter as it goes inward in the axial direction from the seal surface is formed on the outer peripheral edge of the seal surface of the stationary seal ring.
In this case, the taper surface formed on the outer peripheral edge of the seal surface of the stationary seal ring increases the liquid contact area with the flushing fluid on the seal surface of the rotary seal ring, so that the seal surface of the rotary seal ring is efficiently cooled. be able to. As a result, it is possible to further suppress the occurrence of thermal strain on the seal surface.

  The first elastic member is preferably a gasket having thermal conductivity. In this case, since the frictional heat generated on the seal surface of the rotary seal ring can be released from the back surface of the rotary seal ring to the retainer via the gasket, it is possible to further suppress the occurrence of thermal strain on the seal surface. .

  According to the mechanical seal of this invention, it can suppress that the flatness of the sealing surface of a rotation sealing ring falls, or the perpendicularity with respect to the rotating shaft of the said sealing surface is impaired.

It is sectional drawing which shows the mechanical seal which concerns on one Embodiment of this invention. It is an expanded sectional view which shows the attachment structure of a rotation sealing ring. It is the front view which looked at the retainer from the machine outer side. It is the front view which looked at the stationary seal ring from the inside of the machine. It is an expanded sectional view showing the modification of the 1st elastic member. It is sectional drawing which shows the conventional mechanical seal.

Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[overall structure]
FIG. 1 is a cross-sectional view showing a mechanical seal according to an embodiment of the present invention. In FIG. 1, this mechanical seal 1 is used as a shaft seal device for rotating fluid equipment such as various industrial pumps, agitators, compressors, blowers, etc., and penetrates the casing C of the rotating fluid equipment and the opening c1 of the casing C. It arrange | positions between the rotating shafts S which do. In this specification, the left side of FIG. 1 is referred to as the outside of the machine, and the right side of FIG. 1 is referred to as the inside of the machine (the same applies to FIGS. 2 and 5).

  As shown in FIG. 1, the mechanical seal 1 includes, as a stationary unit, an annular seal case 2 fixed to the casing C, and an annular stationary seal fitted and fixed to the inner peripheral surface of the seal case 2. Ring 3. In the seal case 2, a supply path 22 for supplying the flushing fluid into the seal case 2 and a discharge path 23 for discharging the flushing fluid in the seal case 2 are formed.

  The stationary seal ring 3 is a member formed of carbon or other material as a main component, and a seal surface 3a is formed at an end portion on the inner side of the machine. On the outer periphery of the stationary seal ring 3, rubber O-rings 15 and 16 are provided for sealing (secondary seal) between the inner peripheral surface of the seal case 2 at two locations in the axial direction.

  The mechanical seal 1 is linked to the drive collar 5 as a rotary unit, a sleeve 4 attached to the rotary shaft S so as to be integrally rotatable, an annular drive collar 5 attached to the outer periphery of the sleeve 4 so as to be integrally rotatable. An annular retainer 6 attached to the outer periphery of the sleeve 4 so as to be integrally rotatable, a rotary seal ring 7 attached to the retainer 6, a plurality of urging members 8 for urging the drive collar 5 to the outside of the machine, And an annular holding member 9 for holding the biasing member 8.

  The sleeve 4 is made of a metal material such as stainless steel (for example, SUS304) and is fitted to the outer peripheral surface of the rotation shaft S. The end of the sleeve 4 on the outside of the machine is arranged on the outside of the machine than the seal case 2, and the end on the inside of the machine is arranged in the casing C. Further, a rubber O-ring 17 is provided on the inner periphery of the central portion in the axial direction of the sleeve 4 so as to seal (secondary seal) with the outer peripheral surface of the rotary shaft S.

  A stopper ring 10 having an annular portion 10a and a cylindrical portion 10b is disposed at the end of the sleeve 4 on the outside of the machine. The inner circumferential surface of the annular portion 10 a is fitted and fixed to the outer circumferential surface of the rotation shaft S, and the inner circumferential surface of the cylindrical portion 10 b is fitted to the outer circumferential surface of the sleeve 4. An end surface 10 c on the inner side of the annular portion 10 a is in contact with an end surface on the outer side of the sleeve 4.

  A plurality of screw holes 10d penetrating in the radial direction are formed in the cylindrical portion 10b at predetermined intervals in the circumferential direction. A set screw (pressing screw) 11 is screwed into the screw hole 10 d, and by tightening the set screw 11, the tip portion presses the outer peripheral surface of the sleeve 4. Thereby, the sleeve 4 is firmly fixed to the rotating shaft S by the stopper ring 10 and the set screw 11.

  The drive collar 5 is made of a metal material such as stainless steel (for example, SUS304), and is attached to the outer peripheral surface of the sleeve 4 so as to be slidable in the axial direction. On the drive collar 5, a plurality of (three in this embodiment) drive pins 13 are fixed to the end portions on the outside of the machine. Specifically, a plurality of screw holes 5 a penetrating in the axial direction are formed in the drive collar 5 at predetermined intervals in the circumferential direction, and each screw hole 5 a is formed at one end of each drive pin 13. The male screw portions 13a are screwed together.

  The holding member 9 is made of a metal material such as stainless steel (for example, SUS304), and is fitted to the outer peripheral surface of the sleeve 4 on the inner side of the machine than the drive collar 5. A plurality of screw holes 9a penetrating in the radial direction are formed in the holding member 9 at predetermined intervals in the circumferential direction, and set screws 12 are screwed into the respective screw holes 9a. By tightening, the tip portion presses the outer peripheral surface of the sleeve 4. Thereby, the holding member 9 is fixed to the sleeve 4 by the set screw 12.

A plurality of holding holes 9b penetrating in the axial direction are formed in the holding member 9 at predetermined intervals in the circumferential direction. In the holding hole 9b, the drive pin 13 is inserted and is held so as to be movable within a predetermined range in the axial direction.
The holding member 9 holds end portions of the plurality of urging members 8 inside the machine at predetermined intervals in the circumferential direction. The urging member 8 is formed of, for example, a compression coil spring, and an end portion on the outside of the machine is in contact with an end surface on the inside of the machine of the drive collar 5. As a result, the drive collar 5 is urged outward by the urging force of the urging member 8.

  The retainer 6 is made of a metal material such as stainless steel (for example, SUS304), and is attached to the outer peripheral surface of the sleeve 4 so as to be slidable in the axial direction. A rubber O-ring 18 is provided on the inner periphery of the retainer 6 to seal (secondary seal) with the outer peripheral surface of the sleeve 4. A plurality of protrusions 61 are formed on the end surface of the retainer 6 on the inner side of the retainer 6 at predetermined intervals in the circumferential direction, and the protrusions 61 are respectively engaged with a plurality of engagement holes 5 b formed in the drive collar 5. Are combined.

  The rotary seal ring 7 is made of, for example, a SiC sintered body having excellent wear resistance and sealing performance, and is attached to the end of the retainer 6 on the outside of the machine. An end surface on the machine outer side of the rotary seal ring 7 is a seal surface 7 a that is in sliding contact with the seal surface 3 a of the stationary seal ring 3. The sliding contact portion between the seal surface 7 a of the rotary seal ring 7 and the seal surface 3 a of the stationary seal ring 3 is cooled and lubricated by the flushing fluid supplied from the supply path 22.

  With the above configuration, when the drive collar 5 receives drive torque from the holding member 9 via the drive pin 13, the retainer 6 is rotationally driven via the protrusion 61, and the drive collar 5, the retainer 6, and the rotary seal ring 7 are driven. Rotates integrally with the rotary shaft S. At this time, the drive collar 5 is urged to the outside of the machine by the urging member 8 while being held so as to be movable in the axial direction with respect to the holding member 9 via the drive pin 13. Thereby, the seal surface 7a of the rotary seal ring 7 is in sliding contact with the seal surface 3a of the stationary seal ring 3 with a predetermined pressure to form a shaft seal portion.

[Mounting structure of rotating seal ring]
FIG. 2 is an enlarged cross-sectional view showing the mounting structure of the rotary seal ring 7. In FIG. 2, an annular groove 62 into which the rotary seal ring 7 is fitted is formed on the end surface of the retainer 6 on the outside of the machine. The diameter of the groove portion 62 is set slightly larger (about 0.2 to 0.5%) than the outer diameter of the rotary seal ring 7, whereby the rotary seal ring 7 is loosely fitted in the groove portion 62.

  An annular first elastic member 31 is interposed between a back surface 7c opposite to the seal surface 7a of the rotary seal ring 7 and a bottom surface 62a of the groove 62 facing the back surface 7c. The first elastic member 31 is disposed in an annular recess 63 formed in the bottom surface 62 a of the groove 62, and seals (secondary seal) between the bottom surface 62 a and the back surface 7 c of the rotary seal ring 7. . Further, the first elastic member 31 is made of an O-ring formed using an elastic material such as fluoro rubber having excellent corrosion resistance, for example, and the back surface 7c of the rotary seal ring 7 is crushed so as not to contact the bottom surface 62a of the groove 62. It is set to teenage.

  An annular second elastic member 32 is interposed between the outer peripheral surface 7b of the rotary seal ring 7 and the peripheral surface 62b of the groove 62 facing the outer peripheral surface 7b. The second elastic member 32 is disposed in a recess 64 formed in the peripheral surface 62b of the groove 62, and seals (secondary seal) between the peripheral surface 62b and the outer peripheral surface 7b of the rotary seal ring 7. Yes. The second elastic member 32 is made of an O-ring formed using an elastic material such as fluororubber having excellent corrosion resistance, for example, and the outer peripheral surface 7b of the rotary seal ring 7 is not in contact with the peripheral surface 62b of the groove 62. It is set as the crushing allowance.

  In the present embodiment, the first and second elastic members 31 and 32 are provided on the back surface 7c side and the outer peripheral surface 7b side of the rotary seal ring 7, respectively, but at least the first elastic member 31 on the back surface 7c side is provided. What is necessary is just to be provided. This is because the flatness of the back surface 7c of the rotary seal ring 7 has a higher degree of adverse effect on the perpendicularity of the seal surface 7a with respect to the rotation axis S than the flatness of the outer peripheral surface 7b. However, from the viewpoint of further stabilizing the performance of the mechanical seal 1 (the performance of the seal between the stationary seal ring 3 and the rotary seal ring 7 serving as the primary seal and the performance of the secondary seal), the outer surface 7b also has the second elasticity. A member 32 is preferably provided.

  FIG. 3 is a front view of the retainer 6 as seen from the outside of the machine. 2 and 3, on the inner peripheral side of the bottom surface 62a of the groove portion 62 in the retainer 6, a plurality of (three in the illustrated example) pins 41 projecting outward from the machine are spaced at predetermined intervals in the circumferential direction. Is formed. These pins 41 are formed integrally with the retainer 6 by, for example, milling the end surface of the retainer 6 on the outside of the machine.

  Each pin 41 is inserted into a plurality of concave grooves 42 formed at predetermined intervals in the circumferential direction on the back surface 7 c of the rotary seal ring 7. In this state, the tip surface of the pin 41 is not in contact with the bottom surface 42 a of the concave groove 42. When the rotary sealing ring 7 tries to rotate with respect to the retainer 6, the side surface 42 b of the concave groove 42 comes into contact with the outer peripheral surface of the pin 41, so that the rotation is restricted. Therefore, in the present embodiment, the pin 41 and the concave groove 42 constitute a detent mechanism 40 that restricts the rotation sealing ring 7 from rotating with respect to the retainer 6.

As described above, since the rotary seal ring 7 is loosely fitted in the groove 62 of the retainer 6, it is possible to reduce the occurrence of residual stress in the rotary seal ring 7 due to the fitting, and as a result, the seal of the rotary seal ring 7 can be reduced. It is possible to suppress the occurrence of distortion on the surface 7a.
Further, since the first elastic member 31 is interposed between the back surface 7c of the rotary seal ring 7 and the bottom surface 62a of the groove portion 62, even if the flatness of the back surface 7c is low, the flatness is reduced to the first level. It can be corrected (absorbed) by one elastic member 31. Further, since the second elastic member 32 is interposed between the outer peripheral surface 7b of the rotary seal ring 7 and the peripheral surface 62b of the groove portion 62, even if the flatness of the outer peripheral surface 7b is low, its flatness The degree can be corrected (absorbed) by the second elastic member 32. Thereby, when the flatness of the said back surface 7c and the outer peripheral surface 7b is low, it can suppress that the rotation sealing ring 7 inclines with respect to the rotating shaft S. FIG.

  Accordingly, when the seal surface 7a of the rotary seal ring 7 is distorted and the flatness of the seal surface 7a is reduced, or when the flatness of the back surface 7c and the outer peripheral surface 7b is low, the rotary seal ring 7 is inclined and the seal surface 7a is tilted. Since the perpendicularity with respect to the rotation axis S can be prevented from being damaged, it is possible to suppress the deterioration of the sealing performance of the mechanical seal 1.

Further, since the mechanical seal 1 is provided with a detent mechanism 40 that restricts the rotation sealing ring 7 from rotating with respect to the retainer 7, the rotation sealing ring 7 does not move even if the rotation sealing ring 7 is loosely fitted into the retainer 6. The rotation with respect to the retainer 6 can be prevented.
Further, the tip surface of the pin 41 on the retainer 6 side that constitutes the anti-rotation mechanism 40 is not in contact with the bottom surface 42a of the concave groove 42 on the rotary seal ring 7 side. It is possible to prevent the ring 7 from being inclined with respect to the rotation axis S.

[Diamond film of rotating seal ring]
In FIG. 2, diamond films d1 to d4 are continuously formed on the entire surface of the rotary seal ring 7 of the present embodiment. The diamond film d1 is formed on the seal surface 7a of the rotary seal ring 7, and the diamond film d2 is formed on the outer peripheral surface 7b of the rotary seal ring 7. The diamond film d3 is formed on the back surface 7c (including the concave groove 42) of the rotary seal ring 7, and the diamond film d4 is formed on the inner peripheral surface 7d of the rotary seal ring 7. In FIG. 2, the film thicknesses of the diamond films d1 to d4 are exaggerated for easy understanding.

  The diamond films d1 to d4 have a large thermal conductivity of 1000 to 2000 W / m · k. For this reason, not only the wear resistance of the seal surface 7a of the rotary seal ring 7 is improved, but also the following effects are obtained. That is, the frictional heat generated on the seal surface 7a of the rotary seal ring 7 is quickly transferred from the diamond film d1 to the diamond film d3 formed on the back surface 7c of the rotary seal ring 7 via the diamond film d2 and the diamond film d3. I can tell you.

  Thereby, the temperature difference between the seal surface 7a and the back surface 7c of the rotary seal ring 7 can be relaxed, and the occurrence of thermal strain due to this temperature difference on the seal surface 7a can be suppressed. As a result, it is possible to suppress a decrease in the flatness of the seal surface 7a, and thus it is possible to further suppress a decrease in the sealing performance of the mechanical seal 1.

  The diamond films d1 to d4 can be manufactured using a general manufacturing technique such as a microwave CVD method or a hot filament CVD method. The thickness of the diamond films d1 to d4 is not particularly limited in the present invention, but is usually 3 to 30 μm, preferably 3 to 10 μm. From the viewpoint that the frictional heat generated on the seal surface 7a of the rotary seal ring 7 is moved to the outer peripheral surface 7b and the inner peripheral surface 7d before moving to the SiC sintered body which is the base material of the rotary seal ring 7, it is 3 μm. The above thickness is desirable. In addition, the thicker the diamond film, the higher the surface roughness of the film, making it difficult to use as a sealing surface for mechanical seals, which are precision mechanical parts. In addition, the residual stress of the diamond film is minimized. From the viewpoint, it is desirably 10 μm or less.

  The diamond films d1 to d4 may have the same thickness or different thicknesses. From the viewpoint of quickly moving the frictional heat generated on the seal surface 7a of the rotary seal ring 7 to the outer peripheral surface 7b and the inner peripheral surface 7d, the film thicknesses of the diamond films d2 and d4 on the outer peripheral surface 7b and the inner peripheral surface 7d are the same. It is desirable that the thickness is equal to or greater than the thickness of the diamond film d2 on the seal surface 7a.

On the sealing surface 7a of the rotary seal ring 7, the surface roughness is increased by forming the diamond film d1. For this reason, in order to ensure the flatness necessary for the seal surface 7a, the surface of the diamond film d1 is finished.
In addition, the surface roughness of the outer peripheral surface 7b and the back surface 7c of the rotary seal ring 7 is increased by forming the diamond films d2 and d3. And it can absorb by the 2nd elastic members 31 and 32, respectively. Therefore, by forming the diamond films d2 and d3 on the outer peripheral surface 7b and the back surface 7c of the rotary seal ring 7, even if the flatness of the outer peripheral surface 7b and the back surface 7c is lowered, the rotary seal ring 7 is inclined and the seal surface 7a. It is possible to effectively prevent the perpendicularity to the rotation axis S from being damaged.

[Tapered surface of stationary seal ring]
As shown in FIG. 2, a taper surface (hydrocut) that gradually increases in diameter from the seal surface 3 a toward the inner side in the axial direction (outside of the machine) of the stationary seal ring 3. ) 3b is formed.
FIG. 4 is a front view of the stationary seal ring 3 as viewed from the inside of the machine. As shown in FIG. 4, the taper surface 3b of the stationary seal ring 3 is formed at a plurality of locations (eight locations in the example) at predetermined intervals in the circumferential direction on the outer peripheral edge of the seal surface 3a.

  Thereby, the flushing fluid supplied from the supply passage 22 (see FIG. 1) slides between the seal surface 3a of the stationary seal ring 3 and the seal surface 7a of the rotary seal ring 7 along the tapered surface 3b of the stationary seal ring 3. Since it becomes easy to enter the contact portion, the sliding contact portion can be efficiently cooled, and the thickness of the lubricating film by the flushing fluid can be increased at the sliding contact portion. In addition, since the taper surface 3b of the rotary seal ring 7 increases the wetted area with the flushing fluid on the seal surface 7a, the seal surface 7a can be further efficiently cooled. As a result, the wear resistance of both the sealing surfaces 3a and 7a can be improved.

[Modification]
FIG. 5 is an enlarged cross-sectional view showing a modification of the first elastic member 31. The first elastic member 31 of the present modification is made of a gasket having thermal conductivity. The thermal conductivity and hardness of the gasket are not particularly limited in the present invention, but preferably the thermal conductivity is 5 to 200 W / m · k, and the hardness is Hs 40 to 90. In this modification, the first elastic member 31 is a gasket, but in addition, the second elastic member 32 may be a gasket.

  As described above, by using a thermally conductive gasket as the first elastic member 31, the frictional heat generated on the seal surface 7a of the rotary seal ring 7 is changed from the diamond film d1 to the diamond film d2 (diamond film d3), This is transmitted to the bottom surface 62 a of the groove 62 of the retainer 6 via the diamond film d 3 and the first elastic member 31. As a result, the frictional heat can be released to the retainer 6, so that the temperature difference between the seal surface 7 a and the back surface 7 c of the rotary seal ring 7 can be further relaxed, and as a result, thermal strain is generated on the seal surface 7 a. This can be further suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims. For example, in the above-described embodiment, the diamond film is formed on the entire circumference of the rotary seal ring 7, but it may be formed at least on the seal surface 7 a.

DESCRIPTION OF SYMBOLS 1 Mechanical seal 2 Seal case 3 Static seal ring 3a Seal surface 3b Tapered surface 4 Sleeve 5 Drive collar 5a Screw hole 5b Engagement hole 6 Retainer 7 Rotating seal ring 7a Seal surface 7b Outer surface 7c Back surface 7d Inner surface 8 Energizing member DESCRIPTION OF SYMBOLS 9 Holding member 9a Screw hole 9b Holding hole 10 Stopper ring 10a Ring part 10b Cylindrical part 10c End surface 10d Screw hole 11 Set screw 12 Set screw 13 Drive pin 13a Male screw part 15 O ring 16 O ring 17 O ring 18 O ring 22 Supply path 23 Discharge path 31 1st elastic member 32 2nd elastic member 40 Anti-rotation mechanism 41 Pin 42 Recessed groove 42a Bottom face 42b Side face 61 Projection part 62 Groove part 62a Bottom face 62b Peripheral surface 63 Recessed part 64 Recessed part C Casing c1 Opening d1 Diamond film d2 Iyamondo film d3 diamond film d4 diamond film S rotary shaft

Claims (5)

A stationary sealing ring attached to the casing side and having a sealing surface;
A retainer attached to the rotary shaft side penetrating the casing so as to be integrally rotatable, and having an annular groove formed on one end surface in the axial direction;
A rotary seal ring that is fitted in the groove of the retainer and has a seal surface that is in sliding contact with the seal surface of the stationary seal ring, and a mechanical seal comprising:
The rotary seal ring is loosely fitted into the groove portion with an annular first elastic member interposed between a back surface opposite to the seal surface and a bottom surface of the groove portion facing the back surface. And
A mechanical seal provided with a detent mechanism for restricting rotation of the rotary seal ring relative to the retainer.   The mechanical seal according to claim 1, wherein an annular second elastic member is interposed between an outer peripheral surface of the rotary seal ring and a peripheral surface of the groove portion facing the outer peripheral surface.   The mechanical seal according to claim 1 or 2, wherein a diamond film is formed on at least a seal surface of the rotary seal ring.   The taper surface which is gradually diameter-expanded as it goes to the axial direction inner side from the said seal surface is formed in the outer periphery of the seal surface of the said stationary sealing ring. mechanical seal.   The mechanical seal according to any one of claims 1 to 4, wherein the first elastic member is a gasket having thermal conductivity.

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