JP2009024836A - Mechanical seal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical seal which can retain a gap between sealing end surfaces in a proper non-contact state or a contact state under a condition where the temperature and/or the pressure of a fluid to be sealed is significantly fluctuated, and demonstrate an excellent and a stable sealing functions. <P>SOLUTION: The fluid to be sealed is sealed at a relative rotation part of opposing end faces 3a and 4a between a first sealing ring 3 fixed on one of a seal case 2 and a rotary shaft 1 passing therethrough, and a second sealing ring 4 retained on the other side so as to be movable in the axial direction and also not to be relatively rotatable via a retention ring 5. The second sealing ring 4 and the retention ring 5 are connected with distortion in a diameter direction of both the rings 4 and 5 mutually interfered by bringing the opposing end faces 4e and 5c of both the rings 4 and 5 into contact therewith with pressure via an O ring 9. The second sealing ring 4 is made of carbon and the retention ring 5 is composed of titanium that a coefficient of thermal expansion and/or a Young's modulus is approximate to a component of the second sealing ring 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes a first sealing ring fixed to one of a sealing case and a rotating shaft penetrating through the sealing case, and a second sealing ring that is axially movable and non-rotatably supported through a holding ring on the other side. A mechanical seal configured to seal a fluid to be sealed at a relative rotating portion of the opposed end surface of the first end face, and in particular, the holding ring and the second sealing ring are coupled in a state where their radial strains interfere with each other. It relates to mechanical seals.

  As a conventional mechanical seal of this type, for example, as shown in FIG. 4 or 6, the first seal ring 103 fixed to the rotary shaft 101 and the seal case 102 can be moved in the axial direction via an O-ring 107. The holding ring 105 held, the spring member 106 interposed between the seal case 102 and the holding ring 105, and the spring member 106 is pressed and urged to the first sealing ring 103 via the holding ring 105. And a second sealed ring 104, and a sealed fluid which is an outer peripheral side region of the sealed end faces 103a and 104a in the relative rotation portion by relative rotation of the sealed end faces 103a and 104a which are opposite end faces of the both sealed rings 103 and 104. What is configured to be able to seal the region H and the non-sealed fluid region (atmospheric region) L which is the inner peripheral region is well known (for example, patent documents) Figure 1 1, see FIG. 4 or FIG. 5).

  Thus, in the mechanical seal shown in FIG. 4 (hereinafter referred to as “first conventional seal”), the connection between the holding ring 105 and the second sealing ring 104 directly presses the opposed end faces 104b and 105a. It is done by. Further, in the mechanical seal shown in FIG. 6 (hereinafter referred to as “second conventional seal”), the connection between the holding ring 105 and the second sealing ring 104 is indirect via the O-ring 109 at the opposing end faces 104b and 105a. It is performed by making it press-contact to. Further, in any case, the first seal ring 103, the second seal ring 104, and the holding ring 105 are made of different materials because of differences in function and shape. In general, the first sealing ring 103 is a hard material such as WC or SiC, the second sealing ring 104 is softer than the constituent material of the first sealing ring 103, and the holding ring 105 is a metal material ( Generally, it is made of stainless steel.

Japanese Utility Model Publication No. 4-134963

  By the way, in the first conventional seal, the opposing end faces 104b, 105a of the second sealing ring 104 and the holding ring 105 are in a frictional engagement state in which they directly press contact with each other. , 105a, these thermal strains and / or pressure strains interfere with each other. That is, both rings 104 and 105 are connected in a state where their radial strains interfere with each other.

On the other hand, both rings 104 and 105 are made of different materials as described above, and their thermal expansion coefficient (linear expansion coefficient) and Young's modulus are greatly different (for example, the thermal expansion of carbon constituting the second sealing ring 104). While the coefficient is 4 × 10 ^{−6 to} 5 × 10 ⁻⁶ mm / ° C. and the Young's modulus is 2500 kg / mm ² , the thermal expansion coefficient of stainless steel, which is a general component of the retaining ring 105, is 16 × 10 ^{−6 to} 20 × 10 ⁻⁶ mm / ° C., and Young's modulus is 19700 kg / mm ² ).

  Therefore, when the first conventional seal is used under conditions in which the temperature and / or pressure of the fluid to be sealed fluctuates greatly, radial strain (thermal strain and / or radial direction in the contact portions 104b and 105a of both rings 104 and 105). The second sealing ring 104 is strongly influenced by the thermal strain and pressure strain of the holding ring 105 and exhibits a completely different strain state from its own thermal strain and pressure strain. It will be different. As a result, the flatness of the sealing end surface 104a of the second sealing ring 104, the concentricity and parallelism with respect to the mating sealing end surface 103a are impaired, and the sealing function due to the relative rotation of the sealing end surfaces 103a and 104a becomes unstable or decreases. In extreme cases, the sealing function may be lost. For example, when the temperature of the sealed fluid is raised, as shown in FIG. 5A, the radial strain amount (thermal expansion amount) e1 of the retaining ring 105 is equal to the radial strain amount (thermal expansion amount) of the second seal ring 104. ) Since it is larger than E1, radial strains interfere with each other at the contact portions 104b and 105a of both rings 104 and 105, and the strain amount of the second sealing ring 104 is increased from its own strain amount. It will be. As a result, a moment M1 in the direction shown in FIG. 5A acts on the holding ring 105 on the second sealing ring 104, and the sealing end face 104a of the second sealing ring 104 becomes the mating sealing end face (first sealing ring 104). The sealing end face 103a of the one sealing ring 103 is inclined inwardly. On the contrary, when the temperature of the sealed fluid is lowered, as shown in FIG. 5B, the radial thermal strain amount (thermal contraction amount) e2 of the holding ring 105 is equal to the radial thermal strain amount of the second sealed ring 104 ( Since the amount of heat shrinkage (E2) is larger than E2, a moment M2 in the direction opposite to that when the temperature is lowered acts on the second sealing ring 104, so that the sealing end face 104a of the second sealing ring 104 acts on the mating sealing end face 103a. On the other hand, it will be tilted outward. The same applies to the case where both rings 104 and 105 cause radial pressure distortion due to the pressure of the sealed fluid. When the sealed fluid changes in pressure, radial strain occurs in the contact portions 104b and 105a. Mutually interfere to generate moments M1 and M2 similar to those described above.

  Further, in the second conventional seal, the O-ring 109 is interposed between the opposed end faces 104b and 105a of the second sealing ring 104 and the holding ring 105, and the opposed end faces 104b and 105a are not in direct contact with each other. Therefore, mutual interference of radial strains at the facing end faces 104b and 105a does not occur. However, the O-ring 109 is sandwiched between the opposed end faces 104b and 105a, and both the rings 104 and 105 are connected in a state where their radial strains interfere with each other via the O-ring 109. Thus, the same problem as the first conventional seal occurs. That is, the radial strain (thermal strain or pressure strain) e1 and e2 of the holding ring 105 is larger than the radial strain (thermal strain or pressure strain) E1 and E2 of the second sealing ring 104. Therefore, the contact point of the O-ring 109 with both the rings 104 and 105 is relatively displaced in the opposite direction. Therefore, a rotational force in the direction shown in FIG. 7A or FIG. 7B is applied to the O-ring 109 in its cross section. As a result, the moment M1 or M2 in the direction shown in FIG. 7A or FIG. 7B acts on the holding ring 105 on the second sealing ring 104, and the second sealing ring 104 is sealed. The end face 104a is inclined inwardly opened (FIG. 7A) or outwardly opened (FIG. 7B) with respect to the mating sealed end face 103a.

  The present invention has been made in view of the above points, and maintains a proper non-contact state or a contact state between the sealed end faces even under conditions in which the temperature and / or pressure of the sealed fluid greatly fluctuates. It is an object of the present invention to provide a mechanical seal that can perform a good and stable sealing function.

The present invention includes a first sealing ring fixed to one of a sealing case and a rotating shaft penetrating through the sealing case, and a second sealing ring that is axially movable and non-rotatably supported through a holding ring on the other side. A mechanical seal configured to seal a fluid to be sealed at a relative rotation portion of the opposed end surface of the first and second holding rings, wherein the holding ring and the second sealing ring are connected in a state where their radial strains interfere with each other. In the mechanical seal, in order to achieve the above-described object, in particular, the holding ring is made of a metal material whose thermal expansion coefficient (linear expansion coefficient) and / or Young's modulus approximates the constituent material of the second sealing ring. It is what we propose. That is, in the mechanical seal of the present invention, when used under high temperature conditions that are strongly affected by thermal strain, the retaining ring is made of a metal material whose thermal expansion coefficient is at least similar to that of the constituent material of the second sealing ring. When used under high pressure conditions that are strongly influenced by pressure strain, the retaining ring is made of a metal material whose Young's modulus approximates that of the second sealing ring. When used under high temperature and high pressure conditions that are strongly affected by both thermal strain and pressure strain, the retaining ring is a metal material whose thermal expansion coefficient and Young's modulus both approximate the components of the second sealing ring. It is composed of. In general, the second sealing ring is made of carbon. In such a case, it is preferable to select titanium or the like as a constituent material of the retaining ring. For example, since the thermal expansion coefficient of titanium is 8 × 10 ⁻⁶ mm / ° C. and the Young's modulus is 11000 kg / mm ² , stainless steel (thermal expansion coefficient: 16 × 10 6), which is a general component of the retaining ring. Carbon expansion coefficient (4 × 10 ^{−6 to} 5 × 10 ⁻⁶ mm / ° C.) and Young's modulus (2500 kg) compared to ^{−6 to} 20 × 10 ⁻⁶ mm / ° C., Young's modulus: 19700 kg / mm ² / Mm ² ).

  In a preferred embodiment, the mechanical seal of the present invention is configured to rotate relative to each other while the sealing end surfaces, which are the opposite end surfaces of both sealing rings, are held in non-contact by the dynamic pressure and / or static pressure generated therebetween. It is a non-contact type mechanical seal constructed in the above, or an end face contact type mechanical seal constructed so as to rotate relative to each other in a state where the sealed end faces as opposed end faces of both sealing rings are in contact with each other. Further, the connection between the holding ring and the second sealing ring is performed by directly pressing and contacting the opposing end faces of both rings in a state where relative rotation of the both rings is prevented by the drive pin, or both In a state where the relative rotation of the rings is prevented by the drive pins, the opposing end faces of both rings are indirectly pressed and contacted via the O-ring.

  In the non-contact type mechanical seal of the present invention, the retaining ring is made of a metal material whose thermal expansion coefficient and / or Young's modulus is similar to the constituent material of the second sealing ring (for example, the second sealing ring is made of carbon. The retaining ring is made of titanium), the diameter of the sealed fluid is between the second sealing ring and the retaining ring even under conditions in which the fluid to be sealed undergoes a large temperature change and / or pressure fluctuation. A great difference in distortion in the direction does not occur, and a satisfactory and stable sealing function can be exhibited without causing the problems described at the beginning.

  FIG. 1 is a longitudinal side view showing a first embodiment of a mechanical seal according to the present invention. As shown in FIG. 1, the mechanical seal in this embodiment is a rotating device in which a rotating shaft 1 extends vertically. This is a vertical non-contact mechanical seal used as a shaft sealing means of an agitator, etc., and is fixed to the rotating shaft 1 with a seal case 2 attached to a shaft sealing portion (not shown) of the rotating device housing. A rotary seal ring 3 as a first seal ring, a stationary seal ring 4 as a second seal ring directly above the rotary seal ring 3 and directly opposite the seal ring 3, and disposed above the stationary seal ring 4 A sealing end face 3a which is provided with a holding ring 5 held by the seal case 2 and a spring member 6 interposed between the seal case 2 and the holding ring 5 and which is the vertically opposed end faces of both the sealing rings 3 and 4. , 4a due to the dynamic pressure generated during A movement configured to shield a sealed fluid region (in-machine gas region) H which is an in-machine region of the rotating device and an unsealed fluid region (atmosphere region) L which is an out-of-machine region while maintaining the touch state. It is a pressure-type non-contact type mechanical seal.

  As shown in FIG. 1, the seal case 2 is a cylindrical structure having a cylindrical guide portion 2a and an annular retainer portion 2b, and is made of a metal material such as stainless steel. The rotating shaft 1 passes through the guide portion 2a and the retainer portion 2b concentrically in the vertical direction.

  The rotary seal ring 3 is made of a hard material such as ceramics such as WC and SiC and cemented carbide, and as shown in FIG. 1, one side end face (upper end face) facing the stationary seal ring 4 is orthogonal to the axis. It is comprised by the sealing end surface 3a which is a smooth plane. The sealed end surface 3a is formed with a dynamic pressure generating groove 3b having an appropriate shape such as a spiral opening to the outer peripheral portion facing the sealed fluid region H. By the action of the dynamic pressure generating groove 3b, both Along with the relative rotation of the sealing rings 3 and 4, a dynamic pressure is generated between the sealing end surfaces 3a and 4a to keep the sealing end surfaces 3a and 4a in a non-contact state in which a fluid film is formed. Thus, in the formation portion of the fluid film, the space between the sealed fluid region H that is the outer peripheral side region of the sealed end surfaces 3a and 4a and the non-sealed fluid region L that is the inner peripheral side region are sealed. ing.

  The stationary seal ring 4 is made of a material softer than the constituent material of the rotary seal ring 3 (in this example, carbon). As shown in FIG. 1, one side end face (lower end face) facing the rotary seal ring 5 is used. Is formed on the sealed end face 4a, which is a smooth plane orthogonal to the axis. As shown in FIG. 1, the stationary seal ring 4 is fitted and held in the guide portion 2a of the seal case 2 so as to be movable in the axial direction with a very small gap. That is, an annular convex portion 4b and an annular concave portion 4c are formed on the outer peripheral portion and the inner peripheral portion on the back side (upper surface side) of the stationary seal ring 4, respectively. The annular convex portion 4b is referred to as, for example, JIS-B0401. By fitting the guide portion 2a with a dimensional tolerance of “clearance fit”, the radial displacement of the stationary seal ring 4 is possible between the outer peripheral surface of the annular convex portion 4b and the inner peripheral surface of the guide portion 2a. Even if it is blocked, a very small gap is formed to allow the movement in the axial direction and the passage of fluid.

As shown in FIG. 1, the holding ring 5 is formed in an L-shaped cross section including a cylindrical held portion 5 a and an annular pressing portion 5 b formed on the tip side (lower end side) thereof. As shown in FIG. 1, the retaining ring 5 is inserted into and held by the inner peripheral portion of the retainer portion 2b of the seal case 2 via an O-ring 7 so that the seal case 2 It is held so as to be movable in the axial direction (vertical direction) in a state where the space is secondarily sealed. The retaining ring 5 is made of a metal material whose thermal expansion coefficient and / or Young's modulus is similar to that of carbon, which is a constituent material of the stationary sealing ring 4. In this example, both the thermal expansion coefficient and Young's modulus are generally used. Titanium (thermal expansion coefficient) similar to carbon (thermal expansion coefficient: 4 × 10 ^{−6 to} 5 × 10 ⁻⁶ mm / ° C., Young's modulus: 2500 kg / mm ² ) compared to stainless steel, which is a typical retaining ring component Coefficient: 8 × 10 ⁻⁶ mm / ° C., Young's modulus (11000 kg / mm ² )

  As shown in FIG. 1, the stationary seal ring 4 has a recess 4d formed therein and an appropriate number of drive pins (only one shown) 8a that can be implanted in the pressing portion 5b of the holding ring 5 are inserted and engaged. Thus, relative rotation with respect to the holding ring 5 is impossible. In addition, as shown in FIG. 1, the retaining ring 5 has a suitable number of drive pins (only one shown) 8b that can be implanted in the retaining ring 5 inserted into a recess 2c formed in the retainer portion 2b of the seal case 2. Thus, relative rotation with respect to the seal case 2 is impossible.

  As shown in FIG. 1, the spring member 6 includes an appropriate number of coil springs (only one is shown) interposed between the retainer portion 2 b of the seal case 2 and the pressing portion 5 b of the holding ring 5. 5 is pressed and urged in a direction toward the rotary seal ring 3 in the axial direction.

  As shown in FIG. 1, the stationary sealing ring 4 and the holding ring 5 are in a non-contact state in which the O-ring 9 is interposed between the opposing end faces 4e and 5c in the axial direction of the rings 4 and 5, and is secondarily sealed. It is connected with.

  That is, a concentric annular groove 5d is formed on the front surface of the holding ring 5, that is, the front surface 5c of the pressing portion 5b, and the O-ring 9 is slightly protruded and held in this annular groove 5d. In combination with the urging action by the spring member 6, the urging force is held to be pressed against the rotary sealing ring 3 in a sealed state having an appropriate clearance with the holding ring 5. As shown in FIG. 1, an annular O-ring holding portion 5e is provided on the front surface 5c of the pressing portion 5b. The annular O-ring holding portion 5e projects into the inner peripheral space of the stationary seal ring 4, that is, the annular recess 4c. ing. The O-ring 9 is pressed against the O-ring holding portion 5e (inner diameter side wall surface portion of the annular groove 5d) by the fluid pressure in the sealed fluid region H in the radial direction, and the outer diameter side wall surface portion 5f of the annular groove 5d. Is held in a non-contact state. That is, the stationary seal ring 4 and the holding ring 5 are in the state in which the relative rotation of the rings 4 and 5 is blocked by the drive pin 9 and the opposite end faces 4e and 4e of the rings 4 and 5 are the same as in the second conventional seal. 5c is connected in a state of being pressed and contacted via the O-ring 11. The radial clearance between the annular recess 4c and the O-ring holding portion 5e is preferably set as small as possible so long as the portions 4c and 5e do not interfere with each other due to distortion of the rings 4 and 5.

  In the non-contact type mechanical seal configured as described above, the stationary seal ring 4 and the holding ring 5 are connected in a state where their radial strains interfere with each other via the O-ring 9. There is a possibility that the same problem as the second conventional seal described at the beginning may occur. However, since the retaining ring 5 is composed of carbon, which is a constituent material of the stationary sealing ring 4, and titanium whose thermal expansion coefficient and Young's modulus are close to each other, even when the temperature and / or pressure of the fluid to be sealed varies greatly, The difference in thermal strain and / or pressure strain in the radial direction of both rings 4 and 5 is small, and the relative displacement in the radial direction at the contact point between both rings 4 and 5 and the O-ring 9 is slight. 9 is absorbed by the elastic deformation of the ring 9, and no rotational force is applied to the O-ring 9 sandwiched between the opposed end faces 4e and 5c of the rings 4 and 5, causing problems as in the second conventional seal. There is no. That is, the moment M1 as shown in FIG. 6 (A) does not occur when the temperature is raised and / or lowered, and the moment M2 as shown in FIG. 6 (B) acts when the temperature is lowered and / or raised. There is no. Therefore, even when used under high temperature conditions or high pressure conditions where the temperature and pressure of the fluid to be sealed fluctuate greatly, the stationary sealing ring 4 does not tilt, and the flatness of the sealed end face 4a and the mating sealed end face The parallelism and concentricity with 3a are maintained properly without being impaired, and the sealing function (non-contact sealing function) by the non-contact type mechanical seal is satisfactorily exhibited.

  By the way, titanium which is a constituent material of the retaining ring 4 has lighter specific gravity than stainless steel which is a general retaining ring constituent material (for example, the specific gravity of titanium is 4.88 while the specific gravity of SUS316 is 7.88). When the shape is the same, the titanium retaining ring 5 is significantly lighter than a typical stainless steel retaining ring. Therefore, the axial movement of the retaining ring 5 is performed smoothly even under conditions where the rotating shaft 1 rotates at a low speed and there are disturbance factors such as equipment vibrations. As a result, the follow-up operation of the stationary sealing ring 4 is smooth. The sealing end surfaces 3a and 4a can be maintained in an appropriate non-contact state. In particular, as shown in FIG. 1, in the case of a vertical non-contact type mechanical seal in which the stationary seal ring 4 is positioned above the rotary seal ring 3, a great merit is exhibited in order to perform an appropriate sealing function. It becomes. That is, in such a vertical non-contact mechanical seal, the weight of the retaining ring 5 functions as a closing force that acts in the direction of closing between the sealed end faces 3a and 4a. However, as described above, the retaining ring 5 is lightweight. Therefore, the weight of the holding ring 5 does not impair the balance with the dynamic pressure generated between the sealed end surfaces 3a and 4a, and the sealed end surfaces 3a and 4a are held in an appropriate non-contact state. be able to.

  Therefore, according to the non-contact type mechanical seal having the above-described configuration, the separation action (the levitation action) of the stationary seal ring 4 due to the dynamic pressure from the rotary seal ring 3 under the condition that the temperature and the pressure greatly fluctuate or under low speed rotation. ) Can be maintained in an appropriate non-contact state between the sealed end faces 3a and 4a, and a good and stable sealing function can be exhibited.

  FIG. 2 is a longitudinal side view showing a second embodiment of the mechanical seal according to the present invention. The mechanical seal in this embodiment is a shaft seal portion (see FIG. 2) of the rotary device housing as shown in FIG. A seal case 22 attached to the rotary shaft 21, a rotary seal ring 23 as a first seal ring fixed to the rotary shaft 21, a holding ring 25 held by the seal case 22 so as to be movable in the axial direction, and a seal case 22 The spring member 26 interposed between the holding ring 5 and the seal case 22 is held by the holding ring 25 so as to be movable in the axial direction, and pressed against the rotary sealing ring 23 by the spring member 26. A stationary sealing ring 24 as a second sealing ring, and an in-machine region of the rotating device by a relative rotational sliding contact action of the sealing end surfaces 23a and 24a as opposed end surfaces of both sealing rings 23 and 24. Is there the sealed fluid region (e.g. the pump chamber) H and a non-sealed fluid region (for example, atmospheric region of the pump outdoor) L and configured end surface contact type mechanical seal to shield which is outside the region.

  As shown in FIG. 2, the seal case 22 is a cylindrical structure and is made of a metal material such as stainless steel. The rotating shaft 1 passes through the seal case 22 concentrically.

  The rotary seal ring 23 is made of a hard material such as ceramics such as WC or SiC or cemented carbide, and is fixed to the rotary shaft 21 via sleeves 21a and 21b. One side end face of the rotary sealing ring 23 is configured as a sealing end face 23a which is a smooth plane orthogonal to the axis.

  The stationary seal ring 24 is made of a softer material (carbon in this example) than the constituent material of the rotary seal ring 23. As will be described later, the opposite end faces 24b and 25a of the holding ring 25 are directly pressed against the holding ring 25. They are connected in contact. One end face of the stationary sealing ring 24 is formed as a sealing end face 24a which is a smooth plane perpendicular to the axis.

  As shown in FIG. 2, the spring member 26 includes an appropriate number of coil springs (only one is shown) interposed between the seal case 22 and the holding ring 25, and the holding ring 25 is rotated and sealed in the axial direction. By pressing and energizing in the direction toward 23, the stationary seal ring 24 is brought into press contact with the rotary seal ring 23.

  As shown in FIG. 2, the holding ring 25 is an annular body having an L-shaped cross section, and is held by the seal case 22 via an O-ring 27 so as to be movable in the axial direction. The relative rotation of the holding ring 25 with respect to the seal case 22 rushes into a recess 22a formed in the seal case 2 with an appropriate number of drive pins (only one shown) 28a that can be implanted in the holding ring 25 as shown in FIG. It is blocked by keeping it engaged.

  A connecting ring 29 is fitted and fixed to the outer peripheral portion of the holding ring 25 via an O-ring 29a, and the stationary sealing ring 24 is internally fitted and held by the connecting ring 29 via an O-ring 29b. 24 and 25 are connected in a state where the opposed end faces 24b and 25a are directly pressed and contacted. The connecting ring 29 is used to connect the rings 24 and 25 in an axially inseparable manner, and relative rotation of the stationary sealing ring 24 with respect to the connecting ring 29 can be implanted in the holding ring 25 as shown in FIG. An appropriate number of drive pins (only one is shown) 28b is blocked by plunging into a recess 24c formed in the stationary seal ring 24. The O-ring 29b provides a secondary seal between the stationary seal ring 24 and the connection ring 29, and absorbs the difference in radial strain between the rings 24 and 29 to absorb the connection ring. The effect of 29 strain on the stationary seal ring 24 is eliminated.

  Thus, the retaining ring 25 is made of a metal material whose thermal expansion coefficient and / or Young's modulus is close to that of carbon, which is a constituent material of the stationary sealing ring 4. In this example, the retaining ring 25 is the same as that of the first embodiment. Similar to the retaining ring 5, both the thermal expansion coefficient and the Young's modulus are made of titanium that approximates carbon as compared with a general retaining ring component (stainless steel). In addition, when a difference in radial strain occurs between the stationary seal ring 24 and the connecting ring 29, it is absorbed by the O-ring 29b, so that both the rings 24 and 29 are made of different materials. Defects (defects due to mutual interference of radial strains) do not occur. Therefore, it is not necessary to consider the relationship (particularly, the relationship with the thermal expansion coefficient and / or Young's modulus) of the constituent material of the connecting ring 29 with the constituent material of the stationary seal ring 24, and generally a metal material such as stainless steel. In this example, it is made of the same titanium as the retaining ring 25. In this way, the connecting ring 29 is made of the same titanium as the holding ring 25, so that the radial direction of both rings 24 and 29 is provided even when the stationary sealing ring 24 is closely fitted in the connecting ring 29. Detrimental effects caused by mutual interference of distortions are avoided.

  By the way, the stationary sealing ring 24 and the holding ring 25 may be coupled without using the coupling ring 29 described above. For example, as shown in FIG. 3, the opposing end faces 24 b and 25 a are brought into direct pressing contact by causing the stationary seal ring 24 to be clamped between the rotary seal ring 23 and the holding ring 25 by the biasing force of the spring member 26. In this state, it is connected to the holding ring 25. In this case, the relative rotation of both rings 24 and 25 is prevented by the drive pin 28b, and the contact surfaces 24b and 25b of both rings 24 and 25 are secondarily sealed by an O-ring 29c.

  In the end surface contact type mechanical seal configured as described above, as shown in FIG. 2 or FIG. 3, the stationary sealing ring 24 and the holding ring 25 made of different materials are provided at the opposite end surfaces 24b and 25a. Since they are connected in a state where they are in direct pressing contact, that is, in a state where the radial strains of both rings 24 and 25 interfere with each other, there is a possibility that problems similar to those of the first conventional seal described at the beginning may occur. However, since the retaining ring 25 is made of carbon, which is a constituent material of the stationary sealing ring 24, and titanium whose thermal expansion coefficient and Young's modulus are close to each other, even when the temperature and / or pressure of the sealed fluid greatly varies, The difference in thermal strain and / or pressure strain in the radial direction of both rings 24 and 25 is small, and the relative displacement in the radial direction in the contact portions 24b and 25a of both rings 24 and 25 is slight. This causes no problems. That is, the moment M1 as shown in FIG. 6 (A) does not occur when the temperature is raised and / or lowered, and the moment M2 as shown in FIG. 6 (B) acts when the temperature is lowered and / or raised. There is no. Therefore, even when used under conditions in which the temperature and / or pressure of the fluid to be sealed fluctuates greatly, the stationary sealing ring 4 does not tilt, and the flatness of the sealed end surface 24a and the parallel with the mating sealed end surface 23a are avoided. The degree of concentricity and the degree of concentricity are maintained properly and the sealing function by the end face contact type mechanical seal is exhibited well.

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

  For example, the present invention can be applied to the above-described non-contact type mechanical seal or end face contact type mechanical seal, and supplies a seal gas having a pressure higher than that of the sealed fluid from a seal gas supply path that penetrates one seal ring to the sealed end face. By doing so, the sealing end surfaces of both sealing rings are applied to a static pressure type non-contact type mechanical seal configured to rotate relative to each other while being held in a non-contact state by a static pressure generated by a seal gas generated between them. Furthermore, by forming a dynamic pressure generating groove on one sealed end face, static pressure due to the seal gas generated between the sealed end faces of both seal rings and dynamic pressure due to the sealed fluid Therefore, the present invention can also be applied to a dynamic pressure type and a static pressure type non-contact type mechanical seal configured to rotate relative to each other while being held in a non-contact state. In addition, the present invention is configured such that the stationary sealing ring and the holding ring are indirectly in contact with each other via the O-ring as shown in FIG. The present invention can be applied to either a mechanical seal or a mechanical seal configured to be in direct pressing contact without an O-ring as shown in FIG. 2 or FIG.

It is a vertical side view which shows 1st Embodiment of the mechanical seal which concerns on this invention. It is a vertical side view which shows 2nd Embodiment of the mechanical seal which concerns on this invention. It is a vertical side view equivalent to FIG. 2 which shows the modification in 2nd Embodiment. It is a vertical side view which shows a 1st conventional seal | sticker. FIG. 5 is an operation explanatory diagram showing an enlarged main part of FIG. 4. It is a vertical side view which shows a 2nd conventional seal | sticker. FIG. 7 is an operation explanatory diagram showing an enlarged main part of FIG. 6.

Explanation of symbols

1 Rotating shaft 2 Seal case 3 Rotating seal ring (first seal ring)
3a Sealing end face of the rotating sealing ring (sealing end face of the first sealing ring)
4 Static seal ring (second seal ring)
4a Sealing end face of stationary sealing ring (sealing end face of second sealing ring)
4e End face of the stationary seal ring (second seal ring) facing the holding ring 5c End face of the holding ring facing the stationary seal ring (second seal ring) 5 Holding ring 6 Spring member 9 O-ring 21 Rotating shaft 22 Seal case 23 Rotating seal ring (first seal ring)
23a Sealing end face of the rotating sealing ring (sealing end face of the first sealing ring)
24 Static seal ring (second seal ring)
24a Sealing end face of stationary sealing ring (sealing end face of second sealing ring)
24b End face facing the holding ring in the stationary sealing ring (second sealing ring) 25 Holding ring 25a End face facing the stationary sealing ring (second sealing ring) in the holding ring 26 Spring member H Sealed fluid region L Non-sealing fluid region

Claims (6)

A seal case and a first seal ring fixed to one of the rotating shafts penetrating the seal case, and an opposite end face of the second seal ring that is axially movable and non-rotatably supported through the holding ring on the other side. In the mechanical seal configured to seal the sealed fluid in the relative rotating portion, wherein the holding ring and the second sealing ring are connected in a state where their radial strains interfere with each other,
A mechanical seal, wherein the retaining ring is made of a metal material having a thermal expansion coefficient and / or a Young's modulus that is similar to the constituent material of the second sealing ring.   It is a non-contact type mechanical seal configured so as to rotate relative to each other in a state in which the sealing end faces as opposed end faces of both sealing rings are held in non-contact by dynamic pressure and / or static pressure generated therebetween. The mechanical seal according to claim 1.   2. The mechanical seal according to claim 1, wherein the mechanical seal is an end surface contact type mechanical seal configured to rotate relative to each other in a state where the sealing end surfaces as opposed end surfaces of both sealing rings are in contact with each other.   The mechanical seal according to any one of claims 1 to 3, wherein the holding ring and the second sealing ring are connected by directly pressing and contacting the opposed end faces of both rings.   The connection between the holding ring and the second sealing ring is performed by pressing and contacting the opposing end faces of both rings via an O-ring. mechanical seal. The mechanical seal according to any one of claims 1 to 5, wherein the holding ring is made of titanium when the second sealing ring is made of carbon.

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