Mechanical seal
The mechanical seal design addresses the issue of elastic wave attenuation by using a pin member to directly transmit vibrations to a sensor, ensuring accurate monitoring of the sliding portion and simplifying the configuration by acting as an anti-rotation member.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- PILLAR CORP
- Filing Date
- 2025-10-07
- Publication Date
- 2026-06-18
AI Technical Summary
Existing mechanical seals face challenges in accurately monitoring the state of the sliding portion between the rotating and stationary seal rings due to attenuation of elastic waves during propagation through backing metals and wave guides, leading to decreased detection accuracy.
A mechanical seal design featuring a pin member inserted through a seal case insertion hole, where the first end contacts the stationary sealing ring and the second end protrudes outside, allowing vibrations or elastic waves to propagate directly to a sensor, thereby suppressing attenuation and enabling accurate monitoring of the sliding portion.
The design allows for precise monitoring of the sliding portion by reducing vibration attenuation and simplifying the seal configuration, while also serving as an anti-rotation member to prevent the stationary sealing ring from rotating with the rotating ring.
Smart Images
Figure JP2025035549_18062026_PF_FP_ABST
Abstract
Description
Mechanical seal 【0001】 This disclosure relates to a mechanical seal. This application claims priority based on Japanese Application No. 2024-218241 filed on December 12, 2024, and incorporates all the descriptions set forth in the above Japanese application. 【0002】 For example, the mechanical seal described in Patent Document 1 includes a stationary seal ring provided in a casing, a rotating seal ring provided on a rotating shaft and sliding on the stationary seal ring, and a sensor disposed outside the casing for monitoring the state of the sliding portion between the stationary seal ring and the rotating seal ring. The sensor is configured to detect an elastic wave generated in the stationary seal ring when the sliding portion is deformed or destroyed through a backing metal that supports the stationary seal ring and a rod-shaped wave guide. 【0003】 Japanese Unexamined Patent Application Publication No. 2023-181150 【0004】 In the above mechanical seal, the elastic wave generated in the stationary seal ring within the casing propagates to the sensor disposed outside the casing through two members (backing metal and wave guide). Therefore, since the elastic wave generated in the stationary seal ring is likely to attenuate while propagating through the two members, there is a problem that the detection accuracy of the elastic wave by the sensor decreases and the state of the sliding portion cannot be accurately monitored. 【0005】 This disclosure has been made in view of such circumstances, and an object thereof is to provide a mechanical seal capable of accurately monitoring the state of the sliding portion between the rotating seal ring and the stationary seal ring. 【0006】(1) The mechanical seal of the present disclosure comprises a seal case surrounding a rotating shaft, a stationary sealing ring disposed within the seal case, and a rotating sealing ring integrally rotatable with the rotating shaft and sliding relative to the stationary sealing ring, wherein the seal case has an insertion hole that connects the inside and outside of the seal case, and a pin member inserted through the insertion hole of the seal case, the pin member having a first end that protrudes into the seal case from the insertion hole and contacts the stationary sealing ring, and a second end that protrudes outside the seal case from the insertion hole. 【0007】 In the mechanical seal of this disclosure, a pin member is inserted through a through hole that connects the inside and outside of the seal case. The first end of the pin member contacts the stationary sealing ring inside the seal case, and the second end of the pin member protrudes outside the seal case. As a result, when the sliding portion between the rotating sealing ring and the stationary sealing ring is deformed or broken, vibrations or elastic waves generated in the stationary sealing ring propagate from the first end to the second end of the pin member. In other words, vibrations or elastic waves generated in the stationary sealing ring inside the seal case propagate outside the seal case only through the pin member. As a result, the attenuation of the vibrations or elastic waves can be suppressed. Therefore, by detecting the vibrations or elastic waves propagated to the second end of the pin member with a sensor, the state of the sliding portion can be accurately monitored. 【0008】 (2) In the mechanical seal of (1) above, it is preferable that the pin member also serves as an anti-rotation member that restricts the stationary sealing ring from rotating together with the rotating sealing ring. In this case, since the pin member also serves as an anti-rotation member that restricts the stationary sealing ring from rotating together with the rotating sealing ring, the configuration of the mechanical seal can be simplified. 【0009】(3) The mechanical seal of (1) or (2) preferably further comprises an elastic member disposed between the inner circumferential surface of the insertion hole and the outer circumferential surface of the pin member. In this case, when the seal case vibrates, the elastic member can suppress the propagation of that vibration from the inner circumferential surface of the insertion hole to the pin member. As a result, the vibration or elastic wave propagating through the pin member is less affected by the vibration of the seal case, and the vibration or elastic wave of the stationary sealing ring can be accurately detected by the sensor. As a result, the state of the sliding portion between the stationary sealing ring and the rotating sealing ring can be monitored more accurately. 【0010】 (4) In the mechanical seal of (3) above, a first restricting surface is provided in the insertion hole of the seal case, extending in a direction intersecting the communication direction of the insertion hole, the pin member has a first opposing surface that is positioned opposite the first restricting surface from one side in the communication direction when inserted into the insertion hole, and the elastic member preferably includes a first elastic member positioned between the first restricting surface and the first opposing surface. In this case, when the pin member attempts to move toward the other side in the communication direction relative to the insertion hole of the seal case, the first opposing surface of the pin member comes into contact with the first elastic member, and the first elastic member comes into contact with the first restricting surface provided in the insertion hole. This makes it possible to restrict the movement of the pin member toward the other side relative to the insertion hole while suppressing direct contact of the seal case. 【0011】(5) In the mechanical seal of (4) above, a second restricting surface is provided in the insertion hole of the seal case at a position further away from the first restricting surface on one side in the communication direction, and it is preferable that the pin member has a second opposing surface that is positioned opposite the second restricting surface from the other side in the communication direction when inserted into the insertion hole, and the elastic member includes a second elastic member positioned between the second restricting surface and the second opposing surface. In this case, when the pin member attempts to move toward one side in the communication direction relative to the insertion hole of the seal case, the second opposing surface of the pin member comes into contact with the second elastic member, and the second elastic member comes into contact with the second restricting surface provided in the insertion hole. This makes it possible to restrict the movement of the pin member toward one side relative to the insertion hole while suppressing direct contact of the pin member with the seal case. 【0012】 (6) In the mechanical seal of (5) above, the first elastic member is preferably an annular member fitted onto the outer circumference of the pin member, and the first opposing surface is preferably an annular surface located inside the seal case more than the second opposing surface, and is inclined so as to gradually move from the inner end to the outer end toward the outside of the seal case. In this case, when fluid in the seal case enters the through hole, the annular first elastic member fitted onto the outer circumference of the pin member is pressed to the outside of the seal case by the pressure of the fluid that has entered the through hole. The first elastic member pressed to the outside of the seal case moves to the outside of the seal case while being pushed outward radially along the inclination of the first opposing surface. As a result, the inner and outer sides of the first elastic member are strongly pressed against the first opposing surface of the pin member and the inner surface of the through hole, respectively, thereby improving the sealing performance of the first elastic member. As a result, it is possible to suppress the leakage of fluid in the seal case through the through hole to the outside of the seal case. 【0013】 The mechanical seal of this disclosure allows for accurate monitoring of the condition of the sliding portion between the rotating sealing ring and the stationary sealing ring. 【0014】This is a cross-sectional view showing a mechanical seal according to the first embodiment of this disclosure. This is an exploded view showing the pin member, first elastic member, second elastic member, spacer, bolt, etc., removed from the insertion hole of the seal case. This is a cross-sectional view showing a mechanical seal according to the second embodiment of this disclosure. 【0015】 Next, preferred embodiments will be described with reference to the attached drawings. [First Embodiment] Figure 1 is a cross-sectional view showing a mechanical seal 1 according to the first embodiment of the present disclosure. In Figure 1, the mechanical seal 1 is used in a rotating device 70 such as a pump or agitator, and seals a fluid to be sealed (solvent, water, or oil, etc.) inside the rotating device 70. The rotating device 70 comprises a rotating shaft 71 and a casing 72 surrounding the rotating shaft 71. 【0016】 In this specification, "axial direction" refers to the direction along the axis X of the rotation axis 71. "Radial direction" refers to the direction perpendicular to the axis X of the rotation axis 71. "Circumferential direction" refers to the direction around the axis X of the rotation axis 71. For convenience, in this specification, the right side of Figure 1 (inside the machine) is referred to as "one axial side," and the left side of Figure 1 (outside the machine) is referred to as "the other axial side." 【0017】 The mechanical seal 1 of this embodiment is a so-called rotary type mechanical seal. The mechanical seal 1 comprises a rotary unit 2 that is integrally rotatable on a rotating shaft 71 and a stationary unit 3 provided on a casing 72. 【0018】 <Rotation Unit> The rotation unit 2 comprises a first retainer 11, a set screw 12, a drive collar 13, a spring 14, a second retainer 15, and a rotation sealing ring 16. The first retainer 11 is formed in an annular shape and is fitted to the outer circumferential surface on one axial side of the rotation shaft 71. Multiple set screws 12 (only one is shown in Figure 1) arranged at intervals in the circumferential direction are tightened radially into the first retainer 11. In this way, the first retainer 11 is fixed to the rotation shaft 71. 【0019】The drive collar 13 is positioned at a distance from the first retainer 11 on the other axial side. The drive collar 13 is formed in an annular shape and is fitted to the outer circumferential surface of the rotating shaft 71 so as to be movable in the axial direction. The drive collar 13 is held in an axially movable manner relative to the first retainer 11 via a drive pin (not shown), and its relative rotation with respect to the first retainer 11 is restricted. 【0020】 Multiple springs 14 are provided between the first retainer 11 and the drive collar 13 at circumferential intervals (only one is shown in Figure 1). The springs 14, through their elastic force, press the drive collar 13 axially toward the other side relative to the first retainer 11. 【0021】 The second retainer 15 is positioned adjacent to the other axial side of the drive collar 13. The second retainer 15 is annular in shape and is fitted to the outer circumferential surface of the rotating shaft 71 so as to be axially movable. One axial end of the second retainer 15 is fixed to the drive collar 13. As a result, the second retainer 15 is held to be axially movable relative to the rotating shaft 71 together with the drive collar 13, and its relative rotation with respect to the drive collar 13 is restricted. The space between the inner circumferential surface of the second retainer 15 and the outer circumferential surface of the rotating shaft 71 is sealed (secondary seal) by an O-ring 17. 【0022】 The rotating sealing ring 16 is formed in an annular shape and is fixed to the other axial end of the second retainer 15. A sealing surface 16a is formed on the other axial side of the rotating sealing ring 16. The rotating sealing ring 16 is pressed axially to the other side via the drive collar 13 and the second retainer 15 by the elastic force of the spring 14. 【0023】 <Standing Unit> The standing unit 3 comprises a seal case 31, a stationary sealing ring 33, a pin member 34, a pair of elastic members 35, a spacer 36, a bolt 37, and a base 38. The pair of elastic members 35 includes a first elastic member 35A and a second elastic member 35B. 【0024】The seal case 31 is formed in a cylindrical shape. The seal case 31 surrounds the rotating shaft 71 and is fixed to the casing 72 in order to partition the internal area A and the external area B of the rotating machine 70. Specifically, one axial side of the seal case 31 is in contact with the other axial side of the casing 72 and is fixed to the casing 72 by bolts (not shown). The space between the one axial side of the seal case 31 and the other axial side of the casing 72 is sealed (secondary seal) by an O-ring 41. 【0025】 The stationary sealing ring 33 is formed in an annular shape and is placed inside the seal case 31. The space between the outer circumferential surface of the stationary sealing ring 33 and the inner circumferential surface of the seal case 31 is sealed (secondary seal) by an O-ring 42. The O-ring 42 prevents the stationary sealing ring 33 from contacting the seal case 31. An engaging portion 33b is provided at the end of the stationary sealing ring 33 on the axial side of the O-ring 42. 【0026】 The engaged portion 33b is, for example, a groove formed at the end of the stationary sealing ring 33. The engaged portion 33b opens to the other axial side of the stationary sealing ring 33 and is formed over the entire radial thickness of the stationary sealing ring 33. Note that the engaged portion 33b is not limited to the groove in this embodiment, and may be, for example, a hole that penetrates the stationary sealing ring 33 radially. 【0027】 A sealing surface 33a is formed on one axial side of the stationary sealing ring 33, facing the sealing surface 16a of the rotating sealing ring 16. The sealing surface 33a of the rotating sealing ring 16, pressed by the spring 14, slides in close contact with the sealing surface 33a of the stationary sealing ring 33. As a result, an internal region A in which the fluid to be sealed is sealed is formed radially outward from the sliding portion (sealing surfaces 16a, 33a) between the rotating sealing ring 16 and the stationary sealing ring 33. Hereinafter, the sliding portion between the rotating sealing ring 16 and the stationary sealing ring 33 will also be referred to as the sliding portion 16a, 33a. 【0028】The seal case 31 has an insertion hole 32 that connects the inside and outside of the seal case 31. The insertion hole 32 in this embodiment is a circular hole formed to penetrate radially from the outer circumferential surface to the inner circumferential surface of the seal case 31. Hereinafter, in this specification, "communication direction" refers to the radial direction of the seal case 31. For convenience, in this specification, the upper side of Figure 1 is referred to as "one side of the communication direction" and the lower side of Figure 1 is referred to as "the other side of the communication direction". 【0029】 The insertion hole 32 is formed in the seal case 31 at a position radially opposite to the engaged portion 33b of the stationary sealing ring 33. The insertion hole 32 has, in order from the other side in the communication direction toward the one side in the communication direction, a small diameter hole portion 32a, a large diameter hole portion 32b, and a threaded hole portion 32c. The small diameter hole portion 32a is formed to be smaller in diameter than the large diameter hole portion 32b. The large diameter hole portion 32b is formed to be smaller in diameter than the threaded hole portion 32c. 【0030】 A first restricting surface 321 is provided within the insertion hole 32 of the seal case 31, extending in a direction intersecting the communication direction. In this embodiment, the first restricting surface 321 is composed of an annular stepped surface formed between the small-diameter hole portion 32a and the large-diameter hole portion 32b of the seal case 31, and extends from its inner circumferential end toward its outer circumferential end in a direction perpendicular to the communication direction. 【0031】 With the pin member 34, the first elastic member 35A, the second elastic member 35B, and the spacer 36 inserted through the insertion hole 32 of the seal case 31 from one side in the communication direction, the shaft portion 37b (described later) of the bolt 37 is tightened into the threaded hole portion 32c of the insertion hole 32. 【0032】 Figure 2 is an exploded view showing the pin member 34, the first elastic member 35A, the second elastic member 35B, the spacer 36, and the bolt 37, etc., removed from the insertion hole 32 of the seal case 31. In Figures 1 and 2, the pin member 34 is a rod-shaped body with a circular cross-section. The pin member 34 is formed to be longer in the communication direction than the insertion hole 32. 【0033】The pin member 34 has a first small-diameter portion 341, a large-diameter portion 342, and a second small-diameter portion 343, arranged in order from the other side in the communication direction toward the one side in the communication direction. The outer diameter of the first small-diameter portion 341 is smaller than the inner diameter of the small-diameter hole portion 32a of the insertion hole 32. The first small-diameter portion 341 is formed to be longer in the communication direction than the small-diameter hole portion 32a. The first small-diameter portion 341 is inserted through the small-diameter hole portion 32a and is not in contact with the inner circumferential surface of the small-diameter hole portion 32a. 【0034】 The first small-diameter portion 341 has a first end portion 341a that protrudes into the seal case 31 from the opening on the other side of the small-diameter hole portion 32a in the communication direction. The first end portion 341a is inserted into the engaged portion 33b of the stationary sealing ring 33 and is in contact with the inner surface of the engaged portion 33b. 【0035】 As a result, even if the rotating sealing ring 16 rotates together with the rotating shaft 71, the stationary sealing ring 33 is in contact with the first small diameter portion 341 (first end portion 341a) of the pin member 34, thus preventing the stationary sealing ring 33 from rotating together with the rotating sealing ring 16. Therefore, the pin member 34 also serves as an anti-rotation member that prevents the stationary sealing ring 33 from rotating together with the rotating sealing ring 16. 【0036】 The outer diameter of the large-diameter portion 342 is larger than the outer diameter of the first small-diameter portion 341 (second small-diameter portion 343) and smaller than the inner diameter of the large-diameter hole portion 32b of the insertion hole 32. The large-diameter portion 342 is formed to be shorter in the communication direction than the large-diameter hole portion 32b. The large-diameter portion 342 is inserted into the large-diameter hole portion 32b and is not in contact with the large-diameter hole portion 32b. 【0037】 The large-diameter portion 342 has a first opposing surface 345 that, when inserted into the large-diameter hole portion 32b, is positioned opposite the first regulating surface 321 from one side in the communication direction. The first opposing surface 345 is the annular end face on the other side in the communication direction of the large-diameter portion 342, and extends from its inner circumferential end toward its outer circumferential end in a direction perpendicular to the communication direction. The first opposing surface 345 is located on the other side in the communication direction (inside the seal case 31) than the second opposing surface 346, which will be described later. The first elastic member 35A is positioned between the first regulating surface 321 and the first opposing surface 345, and between the inner circumferential surface of the large-diameter hole portion 32b and the outer circumferential surface of the first small-diameter portion 341. 【0038】The first elastic member 35A is an annular member, for example, an O-ring. The first elastic member 35A is fitted onto the outer circumference of the first small-diameter portion 341 from the other side in the communication direction. A radial interference fit (left-right direction in Figure 1) of the first elastic member 35A is provided between the inner circumferential surface of the large-diameter hole portion 32b and the outer circumferential surface of the first small-diameter portion 341. This radial interference fit is set to such an extent that the inner circumferential surface of the large-diameter hole portion 32b and the outer circumferential surface of the first small-diameter portion 341 do not come into contact. On the other hand, there is no interference fit in the communication direction of the first elastic member 35A between the first restricting surface 321 of the insertion hole 32 and the first opposing surface 345 of the large-diameter portion 342. 【0039】 The second small-diameter portion 343 of the pin member 34 has the same outer diameter as the first small-diameter portion 341. The second small-diameter portion 343 is longer in the communication direction than the first small-diameter portion 341. The second small-diameter portion 343 has a second end portion 343a that protrudes outside the seal case 31 from the opening on one side of the insertion hole 32 in the communication direction. In this embodiment, the second end portion 343a is a threaded portion with male threads formed on its outer circumference. Hereinafter, the second end portion 343a will also be referred to as the threaded portion 343a. The second small-diameter portion 343 may have a different outer diameter than the first small-diameter portion 341. The length of the second small-diameter portion 343 in the communication direction may be less than or equal to the length of the first small-diameter portion 341 in the communication direction. 【0040】 The spacer 36 is formed in a cylindrical shape. The inner diameter of the spacer 36 is larger than the outer diameter of the second small diameter portion 343. The outer diameter of the spacer 36 is slightly smaller than the inner diameter of the large diameter hole portion 32b. The spacer 36 is fitted onto the outer circumference of the second small diameter portion 343 from one side in the communication direction. The second small diameter portion 343 is not in contact with the inner circumferential surface of the spacer 36. 【0041】With the spacer 36 fitted around the outer periphery of the second small-diameter portion 343, the end portion of the spacer 36 on the other side in the communication direction is inserted into the large-diameter hole portion 32b of the insertion hole 32. As a result, a second regulating surface 322 is provided at a position in the large-diameter hole portion 32b of the seal case 31 that is farther from the first regulating surface 321 than the other side in the communication direction. The second regulating surface 322 of the present embodiment is formed by an annular end surface of the spacer 36 on the other side in the communication direction. The second regulating surface 322 extends in a direction intersecting the communication direction. The second regulating surface 322 of the present embodiment extends in a direction orthogonal to the communication direction from its inner peripheral end to its outer peripheral end. 【0042】 In the state shown in FIG. 1, the large-diameter portion 342 of the pin member 34 has an annular second opposing surface 346 that is disposed to face the second regulating surface 322 from the other side in the communication direction. The second opposing surface 346 is an end surface of the large-diameter portion 342 on the one side in the communication direction and extends in a direction orthogonal to the communication direction. A second elastic member 35B is disposed between the second regulating surface 322 and the second opposing surface 346 and between the inner peripheral surface of the large-diameter hole portion 32b and the outer peripheral surface of the second small-diameter portion 343. 【0043】 The second elastic member 35B is an annular member, for example, an O-ring. The second elastic member 35B is fitted around the outer periphery of the second small-diameter portion 343 from the one side in the communication direction, prior to the spacer 36. A radial tightening allowance (in the left-right direction in FIG. 1) of the second elastic member 35B is provided between the inner peripheral surface of the large-diameter hole portion 32b and the outer peripheral surface of the second small-diameter portion 343. This radial tightening allowance is set such that the inner peripheral surface of the large-diameter hole portion 32b and the outer peripheral surface of the second small-diameter portion 343 do not come into contact. On the other hand, no tightening allowance in the communication direction of the second elastic member 35B is provided between the first regulating surface 321 of the insertion hole 32 and the first opposing surface 345 of the large-diameter portion 342. 【0044】 As described above, in the insertion hole 32, a radial tightening allowance for the first elastic member 35A and the second elastic member 35B is provided, and no tightening allowance in the communication direction is provided. Thereby, while suppressing the pin member 34 from moving radially and contacting the inner peripheral surface of the insertion hole 32, movement of the pin member 34 in the communication direction due to vibration of the stationary seal ring 33 or the like is permitted. 【0045】The bolt 37 is, for example, a hexagonal bolt and has a head 37a and a shaft portion 37b with male threads formed on the outer periphery. The shaft portion 37b is tightened into the threaded hole portion 32c of the insertion hole 32, and the head 37a is in contact with the outer peripheral surface of the seal case 31. In this state, the end face on the other side in the communication direction of the shaft portion 37b abuts against the end face on one side in the communication direction of the spacer 36. Thereby, the movement of the spacer 36 in the one side direction in the communication direction is restricted. 【0046】 A through hole 37c penetrating the head 37a and the shaft portion 37b in the communication direction is formed in the bolt 37. The inner diameter of the through hole 37c is larger than the outer diameter of the second small diameter portion 343 of the pin member 34. The second small diameter portion 343 is inserted into the through hole 37c of the bolt 37. The second small diameter portion 343 is not in contact with the inner peripheral surface of the through hole 37c. In the state where the shaft portion 37b of the bolt 37 is tightened into the threaded hole portion 32c of the insertion hole 32, the second end portion 343a of the second small diameter portion 343 protrudes to the one side in the communication direction from the head 37a of the bolt 37. 【0047】 When the spacer 36 can be held in the insertion hole 32, it is not necessary to provide the bolt 37 in the insertion hole 32. In that case, it is not necessary to form the threaded hole portion 32c in the insertion hole 32. 【0048】 The pedestal 38 is, for example, a disc-shaped member. A threaded hole 38a is formed to penetrate the central portion of the pedestal 38 in the communication direction. The threaded portion 343a of the pin member 34 that has passed through the bolt 37 is tightened into the threaded hole 38a of the pedestal 38. In the state where the threaded portion 343a is tightened into the threaded hole 38a, the tip end face of the threaded portion 343a is flush with the end face 38b on one side in the communication direction of the pedestal 38. 【0049】A sensor (not shown) is installed on the end face 38b of the base 38. The sensor in this embodiment is a vibration sensor. When the sliding portions 16a and 33a between the rotating sealing ring 16 and the stationary sealing ring 33 are deformed or broken, the vibration generated in the stationary sealing ring 33 propagates from the first end 341a of the pin member 34, which is in contact with the stationary sealing ring 33, to the second end 343a outside the seal case 31. The vibration sensor detects the vibration propagated from the second end 343a to the base 38. In this way, the vibration sensor indirectly detects the vibration generated in the stationary sealing ring 33. By detecting the vibration of the stationary sealing ring 33 with the vibration sensor, the state of the sliding portions 16a and 33a inside the seal case 31 can be monitored. 【0050】 The sensor may also be an acoustic emission (AE) sensor that detects elastic waves generated in the stationary sealing ring 33 when the sliding parts 16a and 33a are deformed or broken. Furthermore, if the sensor can be installed on the tip surface of the second end 343a of the pin member 34, it is not necessary to provide a base 38 on the second end 343a. In that case, it is not necessary to make the second end 343a a threaded portion. 【0051】 <Effects and Effects> In the mechanical seal 1 of the first embodiment, a pin member 34 is inserted through a through hole 32 that connects the inside and outside of the seal case 31. The first end 341a of the pin member 34 contacts the stationary sealing ring 33 inside the seal case 31, and the second end 343a of the pin member 34 protrudes outside the seal case 31. As a result, when the sliding portions 16a and 33a between the rotating sealing ring 16 and the stationary sealing ring 33 are deformed or broken, vibrations generated in the stationary sealing ring 33 are transmitted from the first end 341a of the pin member 34 through the second end 343a to the base 38. In other words, vibrations generated in the stationary sealing ring 33 inside the seal case 31 are transmitted outside the seal case 31 only through the pin member 34. As a result, the attenuation of the vibrations can be suppressed. Therefore, by detecting the vibrations transmitted to the second end 343a of the pin member 34 with a vibration sensor, the state of the sliding portions 16a and 33a can be accurately monitored. 【0052】The pin member 34 also serves as an anti-rotation member that restricts the stationary sealing ring 33 from rotating together with the rotating sealing ring 16. This simplifies the configuration of the mechanical seal 1. 【0053】 An elastic member 35 is positioned between the inner circumferential surface of the insertion hole 32 of the seal case 31 and the outer circumferential surface of the pin member 34. Therefore, when the seal case 31 vibrates, the elastic member 35 can suppress the propagation of that vibration from the inner circumferential surface of the insertion hole 32 to the pin member 34. As a result, the vibrations propagating through the pin member 34 are less affected by the vibrations of the seal case 31, and the vibrations of the stationary sealing ring 33 can be accurately detected by the vibration sensor. Consequently, the state of the sliding portions 16a and 33a between the rotating sealing ring 16 and the stationary sealing ring 33 can be monitored with even greater accuracy. 【0054】 A first elastic member 35A is positioned between the first regulating surface 321 in the insertion hole 32 and the first opposing surface 345 of the pin member 34. Therefore, if the pin member 34 attempts to move significantly in the other direction relative to the insertion hole 32 of the seal case 31 compared to the propagating vibration, the first opposing surface 345 of the pin member 34 will come into contact with the first elastic member 35A, and the first elastic member 35A will come into contact with the first regulating surface 321 in the insertion hole 32. This prevents the pin member 34 from directly contacting the seal case 31 while limiting its movement significantly in the other direction relative to the insertion hole 32. 【0055】 A second elastic member 35B is positioned between the second regulating surface 322 in the insertion hole 32 and the second opposing surface 346 of the pin member 34. Therefore, if the pin member 34 attempts to move significantly to one side in the communication direction relative to the insertion hole 32 of the seal case 31, the second opposing surface 346 of the pin member 34 will come into contact with the second elastic member 35B, and the second elastic member 35B will come into contact with the second regulating surface 322 in the insertion hole 32. This prevents the pin member 34 from directly contacting the seal case 31 while limiting its movement to one side in the communication direction relative to the insertion hole 32. 【0056】[Second Embodiment] Figure 3 is a cross-sectional view showing a mechanical seal 1 according to the second embodiment of the present disclosure. In the mechanical seal 1 of this embodiment, the shape of the first opposing surface 345 of the pin member 34 differs from that of the first embodiment. In Figure 3, the first opposing surface 345 of the pin member 34 of this embodiment is inclined so as it moves from its inner circumference towards its outer circumference, it gradually moves toward one side in the communication direction (outside the seal case 31). 【0057】 The first elastic member 35A is positioned between the first regulating surface 321 and the first opposing surface 345, on the inner circumferential end side of the first opposing surface 345. A radial interference fit (left-right direction in Figure 3) of the first elastic member 35A is provided between the first opposing surface 345 and the inner circumferential surface of the large-diameter hole 32b. This interference fit gradually decreases from the inner circumferential end to the outer circumferential end of the first opposing surface 345. Other components of this embodiment are the same as those of the first embodiment, and are therefore given the same reference numerals, and their descriptions are omitted. 【0058】 Based on the above, the mechanical seal 1 of the second embodiment also provides the same effects as the first embodiment. Furthermore, the first opposing surface 345 of the pin member 34 is inclined so as to gradually move from its inner circumference towards its outer circumference towards one side in the communication direction, thus providing the following effects. 【0059】 When the sealed fluid in internal region A leaks to external region B and enters the through hole 32, the first elastic member 35A, positioned on the inner circumferential end side of the first opposing surface 345, is pressed to one side in the communication direction (outside the seal case 31) by the pressure of the sealed fluid that has entered the through hole 32. Pressed to one side in the communication direction, the first elastic member 35A moves to one side in the communication direction while being pushed radially outward (towards the outer circumferential end side of the first opposing surface 345) along the inclination of the first opposing surface 345. As a result, the inner and outer circumferential sides of the first elastic member 35A are strongly pressed against the first opposing surface 345 of the pin member 34 and the inner circumferential surface of the through hole 32, respectively, thereby improving the sealing performance of the first elastic member 35A. Consequently, leakage of the sealed fluid through the through hole 32 to the outside of the seal case 31 can be suppressed. 【0060】[Other] The "first" designation for the first regulating surface 321, the first opposing surface 345, and the first elastic member 35A, and the "second" designation for the second regulating surface 322, the second opposing surface 346, and the second elastic member 35B, are used to distinguish between the regulating surface, the opposing surface, and the elastic member, respectively. Therefore, these "first" and "second" designations may be used in reverse. 【0061】 In each of the above embodiments, the insertion hole 32 penetrates the seal case 31 radially, but if the stationary sealing ring 33 is positioned on one axial side of the seal case 31, it may also penetrate the seal case 31 axially. In each of the above embodiments, the pin member 34 also serves as an anti-rotation member that restricts the stationary sealing ring 33 from rotating together with the rotating sealing ring 16, but it may be provided separately from the anti-rotation member. 【0062】 The mechanical seal 1 in this embodiment is a rotary type in which a spring 14 presses against a rotary sealing ring 16, but it may also be a stationary type in which a spring presses against a stationary sealing ring 33. The elastic member 35 may include at least one of a first elastic member 35A and a second elastic member 35B. Alternatively, a groove may be provided on the outer circumference of the large diameter portion 342, and the elastic member 35 may be provided between the groove and the inner circumferential surface of the insertion hole 32 (large diameter hole portion 32b). 【0063】 The first restricting surface 321, like the second restricting surface 322, may be formed by the end face of a spacer or the like, inserted separately from the seal case 31 into the insertion hole 32. The spacer 36 does not need to be inserted into the insertion hole 32 of the seal case 31. In that case, the end face on the other side in the communication direction of the shaft portion 37b of the bolt 37 may be used as the second restricting surface 322. 【0064】The configuration of the insertion hole 32 of the seal case 31 is not limited to this embodiment. For example, the insertion hole 32 may not have a threaded hole portion 32c, but rather have a large-diameter hole portion 32b extended to one side in the communication direction and opened on the outer circumferential surface of the seal case 31. In that case, the spacer 36 is inserted into the large-diameter hole portion 32b, but the bolt 37 cannot be tightened into the large-diameter hole portion 32b. For this reason, instead of the bolt 37, a member that abuts against the end face of the spacer 36 inserted into the large-diameter hole portion 32b on one side in the communication direction and restricts the movement of the spacer 36 to that side in the communication direction may be attached to the outer circumferential surface of the seal case 31. 【0065】 The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims, not in the sense described above, and is intended to include all modifications within the meaning and scope of the equivalents of the claims. 【0066】 1 Mechanical seal 16 Rotating sealing ring 31 Seal case 32 Through hole 33 Stationary sealing ring 34 Pin member 35 Elastic member 35A First elastic member 35B Second elastic member 71 Rotating shaft 321 First restricting surface 322 Second restricting surface 341 First small diameter portion (anti-rotation member) 341a First end 343a Second end 345 First opposing surface 346 Second opposing surface
Claims
1. A mechanical seal comprising: a seal case surrounding a rotating shaft; a stationary sealing ring disposed within the seal case; and a rotating sealing ring integrally rotatable with the rotating shaft and sliding relative to the stationary sealing ring, wherein the seal case has an insertion hole connecting the inside and outside of the seal case, and a pin member inserted through the insertion hole of the seal case, the pin member having a first end protruding into the seal case from the insertion hole and in contact with the stationary sealing ring, and a second end protruding out of the seal case from the insertion hole.
2. The mechanical seal according to claim 1, wherein the pin member also serves as an anti-rotation member that restricts the stationary sealing ring from rotating together with the rotating sealing ring.
3. The mechanical seal according to claim 1 or claim 2, further comprising an elastic member disposed between the inner circumferential surface of the insertion hole and the outer circumferential surface of the pin member.
4. The mechanical seal according to claim 3, wherein a first restricting surface is provided in the insertion hole of the seal case, extending in a direction intersecting the communication direction of the insertion hole, the pin member has a first opposing surface that is positioned opposite the first restricting surface from one side in the communication direction when inserted into the insertion hole, and the elastic member includes a first elastic member positioned between the first restricting surface and the first opposing surface.
5. The mechanical seal according to claim 4, wherein a second restricting surface is provided in the insertion hole of the seal case, at a position further away from the first restricting surface on one side in the communication direction, and extending in a direction intersecting the communication direction; the pin member has a second opposing surface that is positioned opposite the second restricting surface from the other side in the communication direction when inserted into the insertion hole; and the elastic member includes a second elastic member positioned between the second restricting surface and the second opposing surface.
6. The mechanical seal according to claim 5, wherein the first elastic member is an annular member fitted onto the outer circumference of the pin member, and the first opposing surface is an annular surface located inside the seal case more than the second opposing surface, and is inclined so as to gradually move from the inner end to the outer end toward the outside of the seal case.