JP2016020714A - mechanical seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal structure under a low cost in a mechanical seal having a fixed ring fixed to a housing under a state in which a motion of a rotary shaft toward a central axis direction is allowed, and a clearance between the housing and the fixed ring can be sealed while the fixed ring is being depressed against the rotary ring.SOLUTION: There is provided a seal structure 400 for sealing a clearance between a housing 300 and a fixed ring 120 while pressing the fixed ring 120 toward a rotary ring 110. The seal structure 400 is constituted by O-rings 411, 412, 413 having different diameters to each other and annular members 420, 430 each of which is arranged between adjoining O-rings. All O-rings 411, 412, 413 are arranged under a state in which recovering force formed by compression deformation may act in both central axial direction and radial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mechanical seal.

  2. Description of the Related Art Conventionally, a mechanical seal is known that includes a stationary ring that is fixed in a state in which movement in the central axis direction of a rotating shaft is allowed with respect to a housing through which the rotating shaft is inserted. In this type of mechanical seal, a rubber shape having a special shape is used to seal the gap between the housing and the fixed ring while pressing the fixed ring toward the rotary ring in the direction of the central axis of the rotary shaft. An elastic packing may be used (see Patent Documents 1 and 2).

International Publication No. 2009/008289 International Publication No. 2012/169297 JP 2008-8318 A

  According to the packing disclosed in the above-mentioned patent document, both pressing of the fixed ring and sealing of the gap between the housing and the fixed ring can be suitably achieved. However, since such a packing has a special shape, the manufacturing cost is generally high.

  An object of the present invention is to provide a mechanical seal including a fixed ring fixed to a housing in a state in which movement of the rotary shaft in the central axis direction is permitted, while pressing the fixed ring toward the rotary ring, An object of the present invention is to provide a sealing structure that can seal a gap between the stationary ring and the fixing ring at a low cost.

The present invention employs the following configuration in order to solve the above problems.
That is, the mechanical seal according to the present invention is
A rotating ring fixed to the rotation axis;
A fixed ring that is fixed to a housing having a shaft hole through which the rotary shaft is inserted, and that slides on an end surface of the rotary ring that faces the central axis direction of the rotary shaft;
A mechanical seal comprising:
In the mechanical seal that is fixed to the housing in a state in which the stationary ring is allowed to move in the direction of the central axis and is restricted in rotational movement,
A sealing structure that seals a gap between the housing and the stationary ring while pressing the stationary ring toward the rotating ring;
The sealing structure is
A plurality of O-rings made of rubber-like elastic bodies having different diameters,
Composed of at least one annular member provided one by one between adjacent O-rings,
Each of the plurality of O-rings is arranged in a state in which a restoring force due to compressive deformation is applied in both the central axis direction and the radial direction.

According to the present invention, all of the plurality of O-rings constituting the sealing structure are arranged in a state in which a restoring force due to compressive deformation acts in both the central axis direction and the radial direction. Therefore, it is possible to seal the gap between the housing and the fixed ring by the radial force while pressing the fixed ring toward the rotating ring by the force in the central axis direction. Here, since the O-ring is a relatively inexpensive general-purpose product that is widely distributed, even if a plurality of O-rings are used, an elastic reaction force is exerted in both the central axis direction and the radial direction. The sealing structure to be exhibited can be obtained at low cost. Therefore, according to the present invention, a sealing structure that seals the gap between the housing and the fixed ring while pressing the fixed ring toward the rotating ring is provided at a lower cost than the packing having the special shape described above. It becomes possible to do.

  Here, the plurality of O-rings are arranged in order from the smallest diameter toward the direction opposite to the pressing direction of the stationary ring, and the smallest O-ring is provided in close contact with the stationary ring. In addition, an O-ring having the largest diameter may be provided in close contact with the housing.

  The stationary ring is provided with an inclined surface that is in close contact with the O-ring having the smallest diameter and expands in the pressing direction of the stationary ring, and the housing has the smallest diameter. There may be provided an inclined surface having a large O-ring in close contact, and having a diameter reduced in a direction opposite to the pressing direction of the stationary ring.

  According to this configuration, both the smallest diameter O-ring in close contact with the stationary ring and the largest diameter O-ring in close contact with the housing are not parallel to either the central axis direction or the radial direction. Compressed in the direction. Thereby, both O-rings can be brought into a state in which a restoring force due to compressive deformation acts in both the central axis direction and the radial direction.

  Furthermore, on the outer peripheral side of the annular member, there is an inclined surface that expands in the pressing direction of the stationary ring, in which an O-ring having a large diameter out of two adjacent O-rings is in close contact with the annular member. The O-ring with a small diameter of the two adjacent O-rings is closely attached to the inner peripheral side of the annular member, and the diameter of the ring decreases toward the opposite direction of the pressing direction of the stationary ring. An inclined surface may be provided.

  According to this configuration, both of the two O-rings that are in close contact with the annular member are compressed in a direction that is not parallel to either the central axial direction or the radial direction. Thereby, both O-rings can be brought into a state in which a restoring force due to compressive deformation acts in both the central axis direction and the radial direction.

  The plurality of O-rings are arranged in order from the largest in the direction opposite to the pressing direction of the stationary ring, and the largest O-ring is provided in close contact with the stationary ring, In addition, an O-ring having the smallest diameter may be provided in close contact with the housing.

  The stationary ring is provided with an inclined surface that is in close contact with the largest diameter O-ring and is reduced in diameter toward the pressing direction of the stationary ring, and the housing has the largest diameter. There may be provided an inclined surface with which a small O-ring is in close contact and whose diameter is increased in the opposite direction to the pressing direction of the stationary ring.

  According to this configuration, both the largest diameter O-ring that is in close contact with the stationary ring and the smallest diameter O-ring that is in close contact with the housing are not parallel to either the central axis direction or the radial direction. Compressed in the direction. Thereby, both O-rings can be brought into a state in which a restoring force due to compressive deformation acts in both the central axis direction and the radial direction.

Furthermore, on the outer peripheral side of the annular member, an inclined surface that decreases in diameter in the pressing direction of the stationary ring, in which an O-ring having a large diameter of two O-rings adjacent to each other through the annular member is in close contact. The diameter of the annular member is increased toward the direction opposite to the pressing direction of the stationary ring, and an O-ring having a small diameter of the two adjacent O-rings is in close contact with the inner peripheral side of the annular member. An inclined surface may be provided.

  According to this configuration, both of the two O-rings that are in close contact with the annular member are compressed in a direction that is not parallel to either the central axial direction or the radial direction. Thereby, both O-rings can be brought into a state in which a restoring force due to compressive deformation acts in both the central axis direction and the radial direction.

  According to the present invention, in a mechanical seal including a stationary ring fixed to a housing in a state in which movement of the rotating shaft in the central axis direction is allowed, the housing and the housing are pressed while pressing the stationary ring toward the rotating ring. It is possible to provide a sealing structure capable of sealing the gap between the stationary ring and the low cost.

It is typical sectional drawing of the mechanical seal which concerns on an Example. It is a typical fragmentary sectional view of the sealing structure of the mechanical seal which concerns on an Example. It is a typical fragmentary sectional view which shows the structure of the other example of the sealing structure which concerns on an Example. It is a typical fragmentary sectional view which shows the structure of the other example of the sealing structure which concerns on an Example. It is a typical fragmentary sectional view which shows the structure of the other example of the sealing structure which concerns on an Example. It is a typical fragmentary sectional view which shows the structure of the other example of the sealing structure which concerns on an Example.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

[Example]
<Configuration of mechanical seal>
With reference to FIG. 1, the structure of the mechanical seal which concerns on the Example of this invention is demonstrated. The mechanical seal 100 according to the present embodiment is a mechanical seal used for sealing an annular gap between the rotating shaft 200 and the housing 300 through which the rotating shaft 200 is inserted. The mechanical seal 100 is preferably used for sealing a high-concentration slurry fluid, a high-viscosity fluid, a fluid that precipitates and adheres, and hinders the operability of the seal. FIG. 1 is a schematic cross-sectional view showing a schematic configuration of the mechanical seal 100 by a plane including the central axis C of the rotation shaft 200. For convenience of explanation, the phase of the cutting position is appropriately changed in order to show a characteristic part. Further, the depth is basically omitted, and only the end face is shown.

  The mechanical seal 100 includes a sleeve 210 fixed to the rotating shaft 200 and a rotating ring 110 fixed to the rotating shaft 200 via the sleeve 210. The rotating ring 110 is made of a material having excellent sliding characteristics such as carbon or a hard material such as ceramic. The rotating ring 110 is fixed to the rotating shaft 200 by fitting the cylindrical portion 111 to the outer peripheral side of the large diameter portion 211 of the sleeve 210. A notch groove 112 is provided on the inner peripheral side of the rotary ring 110, and the central axis of the rotary shaft 200 from the atmosphere side A (right side in FIG. 1) of the large diameter portion 211 in the notch groove 112. The rotation of the rotating ring 110 is restricted by fitting a knock pin 212 that protrudes in a direction (hereinafter simply referred to as a “center axis direction”).

  The mechanical seal 100 includes a fixed ring 120 fixed to the housing 300 having a shaft hole 310 through which the rotating shaft 200 is inserted. The end surface 121 of the stationary ring 120 on the sealing region side B (left side in FIG. 1) slides with respect to the end surface 113 of the rotating ring 110 facing the central axis direction (atmosphere side A direction). Thereby, since a sealing surface is formed between both end surfaces, the annular gap between the rotating shaft 200 and the housing 300 is sealed. Note that the fixed ring 120 is made of a hard material such as carbon or ceramic, like the rotating ring 110.

  Here, the housing 300 includes a main body 301 and an end 302 provided on the sealed region side B of the main body 301. A pin hole 303 is provided in the right end surface of the end portion 302 in the drawing, and the rotation of the end portion 302 is restricted by fitting a knock pin 304 protruding from the main body portion 301 in the central axis direction into the pin hole 303. Has been. In the present embodiment, the end portion 302 is formed of a member different from the main body portion 301, but these may be formed integrally. A knock pin 306 projecting in the central axis direction is provided from the end surface 305 of the end portion 302 facing the sealing region B side. The knock pin 306 is fitted into a notch groove 122 provided in the fixed ring 120. ing. As a result, the stationary ring 120 is fixed to the housing 300 in a state where rotational movement is restricted while movement in the central axis direction is allowed. In addition, a spring 307 is provided on the end surface 305 of the end portion 302 so that the fixed ring 120 faces the rotating ring 110 and presses in the direction of the central axis indicated by the arrow P in the drawing (hereinafter, this direction is referred to as “pressing”). Direction P)). Due to the pressing force by the spring 307, a sealing surface is stably formed between the rotating ring 110 and the stationary ring 120 even when the rotating shaft 200 rotates. A plurality of springs 307 are arranged at rotationally symmetric positions. However, if the stationary ring 120 is sufficiently pressed in the pressing direction P by the restoring force (elastic reaction force) of the O-rings 411, 412, and 413, which will be described later, the spring 307 may not be disposed.

  Here, the mechanical seal 100 according to the present embodiment includes a sealing structure 400 that seals a gap between the housing 300 and the fixed ring 120 while pressing the fixed ring 120 toward the rotating ring 110. The sealing structure 400 includes O-rings 411, 412, and 413 made of rubber-like elastic bodies having different diameters, and annular members 420 and 430 provided one by one between adjacent O-rings. Here, the “diameter” of the O-ring means the outer diameter of the O-ring. That is, the O-rings 411, 412, and 413 have different outer diameters. However, for example, O-rings having different inner diameters or O-rings having different average diameters may be used. These O-rings are arranged in the order of decreasing diameter in the direction opposite to the pressing direction P of the stationary ring 120. In the present embodiment, the O-rings 411, 412, and 413 are relatively inexpensive general-purpose products widely distributed in the market, and the same wire diameter and material are used.

<Configuration of sealing structure>
Hereinafter, the sealing structure 400 will be described in detail with reference to FIG. FIG. 2 is a schematic partial cross-sectional view showing the configuration of the sealing structure 400, and shows only one end face of the central axis C of the rotating shaft 200 for explanation. The sealing structure 400 has a rotationally symmetric shape.

The annular members 420 and 430 are members made of a rigid body such as stainless steel. The annular member 430 has an outer diameter larger than that of the annular member 420, but in this embodiment, the cut end surfaces of both annular members are formed in the same shape. On the outer peripheral side of the annular member 420, an inclined surface 422 that is enlarged in the pressing direction P is formed. On the other hand, on the inner peripheral side of the annular member 420, an inclined surface 421 that is reduced in diameter in the direction opposite to the pressing direction P is provided. In the present embodiment, the inclined surface 421 is formed of a curved surface formed so as to substantially follow the outer peripheral surface of the compressed O-ring 411. Thereby, the O-ring 41 with respect to the annular member 420
1 positioning is performed. On the other hand, the inclined surface 422 is composed of a tapered surface. Thereby, the acting direction of the restoring force of the O-ring 411 described later is defined. Note that side surfaces 423 and 424 for preventing the O-ring 412 from falling off are formed at both end edges of the inclined surface 422. Similar to the annular member 420, an inclined surface 431 and an inclined surface 432 are formed on the inner peripheral side and the outer peripheral side of the annular member 430. Also, side surfaces 433 and 434 for preventing the O-ring 413 from falling off are formed at both end edges of the inclined surface 432 in the same manner as the inclined surface 422. The sealing structure 400 fixes the thickness of the annular member 420 (distance between the inclined surface 421 and the inclined surface 422) and the thickness of the annular member 430 (distance between the inclined surface 431 and the inclined surface 432). The thickness is set such that all of the O-rings 411, 412, and 413 are compressed when mounted in the annular gap between the ring 120 and the end portion 302.

  An inclined surface 123 and side surfaces 124 and 125 having the same shape as the above-described inclined surface 422 and side surfaces 423 and 424 are formed on the outer peripheral side of the fixed ring 120. In addition, an inclined surface 311 having the same shape as the above-described inclined surface 421 is formed on the end portion 302 of the housing 300.

  In the sealing structure 400 configured as described above, the O-ring 411 having the smallest diameter is provided in close contact with the inclined surface 123 on the outer peripheral side of the stationary ring 120 and the inclined surface 421 on the inner peripheral side of the annular member 420. It is done. The O-ring 413 having the largest diameter is provided in close contact with the inclined surface 432 on the outer peripheral side of the annular member 430 and the inclined surface 311 of the end portion 302. The O-ring 412 is provided in close contact with the inclined surface 422 on the outer peripheral side of the annular member 420 and the inclined surface 431 on the inner peripheral side of the annular member 430. As described above, any of the O-rings 411, 412, and 413 is compressed in a direction that is not parallel to either the central axis direction or the radial direction by the inclined surfaces that are in close contact with each other. As a result, the restoring force due to the compressive deformation of each O-ring acts in a direction not parallel to either the central axis direction or the radial direction. Here, taking the O-ring 411 as an example, as shown in FIG. 2, the restoring force F of the O-ring 411 has a shape of the inclined surface 123 (for example, the inclined surface in FIG. 2) with respect to the inclined surface 123. Acting on the direction of the arrow F, which is a direction corresponding to the angle of the ridgeline of 123. As a result, both the component force F1 (arrow F1) in the central axis direction and the component force F2 (arrow F2) in the radial direction of the restoring force F act on the stationary ring 120. The restoring force F of the O-ring 411 acts on the annular member 420 in the direction opposite to the arrow F. The restoring forces of the O-rings 412 and 413 also act bidirectionally in the same manner. As described above, all of these O-rings are arranged in a state in which a restoring force due to compressive deformation acts in both the central axis direction and the radial direction. Therefore, according to the sealing structure 400, the stationary ring 120 is pressed toward the rotating ring 110 by the force in the central axis direction of each O-ring. Moreover, the annular gap between each of the fixed ring 120, the annular members 420, 430 and the end portion 302 is stably sealed by the radial force of each O-ring.

<Excellent points of mechanical seal according to this embodiment>
According to the mechanical seal 100 configured as described above, any of the O-rings 411, 412, and 413 included in the sealing structure 400 is in a state in which a restoring force due to compressive deformation acts in both the central axis direction and the radial direction. Be placed. As a result, the gap between the housing 300 and the stationary ring 120 can be sealed by the radial force while pressing the stationary ring 120 toward the rotating ring 110 by the force in the central axis direction. Here, since these O-rings are relatively inexpensive general-purpose products that are widely distributed, even if a plurality of O-rings are used, they are elastic against both the central axis direction and the radial direction. A sealing structure that exerts the force can be obtained at low cost. Therefore, according to the present embodiment, it is possible to provide such a sealing structure at a lower cost than the packing having the special shape according to the above-described prior art.

Further, according to the sealing structure 400 of the mechanical seal 100, the stationary ring 120 is provided with the inclined surface 123 whose diameter increases in the pressing direction P, and the end portion 302 of the housing 300 has the pressing direction P in the pressing direction P. An inclined surface 311 that decreases in diameter in the opposite direction is provided. In addition, inclined surfaces 422 and 432 that increase in diameter toward the pressing direction P are provided on the outer peripheral side of the annular members 420 and 430, respectively, and the opposite direction of the pressing direction P is provided on the inner peripheral side of both annular members. Inclined surfaces 421 and 431 each having a diameter decreasing toward the surface are provided. With the configuration described above, all of the O-rings 411, 412, and 413 are compressed in a direction that is not parallel to either the central axis direction or the radial direction. Can be made to act in both the central axis direction and the radial direction.

  Further, according to the sealing structure 400, the stationary ring 120 is pressed uniformly in the circumferential direction (entirely) by the force in the central axis direction of each O-ring. Therefore, it is possible to stably form a seal surface between the fixed ring 120 and the rotating ring 110. This makes it possible to stably seal a fluid to be sealed such as a high-concentration slurry fluid. Further, according to the sealing structure 400, a plurality of O-rings and a plurality of annular members are provided in multiple stages. Therefore, even if the annular gap between the fixed ring 120 and the housing 300 is relatively large, it can be sealed.

  Here, in the sealing structure 400, the materials and wire diameters of the respective O-rings are the same, but they may be different from each other. That is, by appropriately selecting the material, wire diameter, etc. of each O-ring, a sealing structure having desired sealing characteristics and elastic characteristics can be obtained easily and inexpensively. Moreover, in the sealing structure 400, although the shape of the cut end surface of each annular member was the same, you may make these mutually different. That is, by appropriately changing the shape of the annular members 420 and 430 (the inclination angle and curvature of the inclined surface closely contacting the O-ring, the distance between the inner peripheral side and the outer peripheral inclined surface, etc.), It becomes possible to make a sealing characteristic and an elastic characteristic into a desired value.

<Other examples of sealing structure>
Next, another example of the mechanical seal sealing structure according to the present invention will be described with reference to FIGS. 3 to 6 are schematic partial cross-sectional views showing configurations of other examples of the sealing structure, and only an end surface on one side of the central axis C of the rotating shaft 200 is shown for the sake of explanation. In addition, about the structure same as the above-mentioned Example, the same code | symbol is attached | subjected and the description is abbreviate | omitted. The operation of the same configuration is also substantially the same.

  FIG. 3 shows an example of a sealing structure composed of two O-rings and one annular member. The sealing structure 401 includes O-rings 411 and 412 and an annular member 420. Also in the sealing structure 401, the same effect as the above-described sealing structure 400 is exhibited. On the other hand, FIG. 4 shows an example of a sealing structure composed of four O-rings and three annular members. The sealing structure 402 further includes an O-ring 414 having an outer diameter larger than the outer diameter of the O-ring 413 and an annular member 440 having an outer diameter larger than the outer diameter of the annular member 430. Also in the sealing structure 402, the same effect as the above-described sealing structure 400 is exhibited. And even if the number of O-rings and the number of annular members provided in the sealing structure are further increased (however, the number of annular members is one smaller than the number of O-rings), the same effect as the sealing structure 400 described above is exhibited. Is done. Thus, according to the present invention, the number of O-rings can be increased or decreased according to the size and shape of the annular gap between the stationary ring 120 and the end 302 or the characteristics required for the sealing structure. . Further, in the sealing structure in which the number of O-rings and the number of annular members are increased or decreased as in the sealing structures 401 and 402, the material and shape of each O-ring and each annular member are appropriately set as in the sealing structure 400. Can be changed.

FIG. 5 shows an example of a sealing structure in which three O-rings are arranged in order from the largest in the direction opposite to the pressing direction P of the stationary ring 120. The sealing structure 403 includes the above-described O-rings 411, 412, and 413 and annular members 450 and 460. The annular portions 450 and 460 are similar to the annular member 420 described above, and the annular member 450 has a larger outer diameter than the annular member 460. In the sealing structure 403, O-rings 411, 412, and 413 are arranged in order of increasing outer diameter from the rotating ring 110 side. The fixed ring 120 is provided with an inclined surface 1230 with a diameter decreasing toward the pressing direction P to which the O-ring 413 is in close contact, and the O-ring 411 is in close contact with the end portion 302 of the housing 300. An inclined surface 3110 that increases in diameter in the direction opposite to the direction P is provided. In addition, on the outer peripheral side of the annular members 450 and 460, O-rings having a large diameter out of two adjacent O-rings are in close contact with each other via the annular member, and inclined surfaces 452 and 462 that decrease in diameter toward the pressing direction P. Are provided. In addition, inclined surfaces 451 and 461 each having an enlarged diameter in the opposite direction to the pressing direction P are provided on the inner peripheral side of both annular members, in which the small O-ring of two adjacent O-rings is in close contact. It has been. In the sealing structure 403, the inclined surfaces 452, 462, 3110 are composed of curved surfaces formed so as to substantially follow the outer peripheral surface of the compressed O-ring. On the other hand, the inclined surfaces 451, 461, and 1230 are tapered surfaces. Thereby, the function similar to the inclined surface in the above-mentioned sealing structure 400 is exhibited. Further, in the sealing structure 403, the spring 307 is disposed on the radially outer side than the O-ring 413. However, if the stationary ring 120 is sufficiently pressed in the pressing direction P by the restoring force of the O-rings 411, 412, and 413, the spring 307 may not be disposed.

  With the above configuration, in the sealing structure 403, all of the O-rings 411, 412, and 413 are compressed in a direction that is not parallel to either the central axis direction or the radial direction. The restoring force due to the compressive deformation can be made to act in both the central axis direction and the radial direction. Therefore, also in the sealing structure 403, the same effect as the above-described sealing structure 400 is exhibited. Also in the sealing structure 403, the number of O-rings and annular members can be increased or decreased as in the sealing structures 401 and 402. Also in the sealing structure 403, the material and shape of each O-ring and each annular member can be changed as appropriate.

  FIG. 6 shows an example of another sealing structure in which three O-rings are arranged in order from the largest in the direction opposite to the pressing direction P of the stationary ring 120. In the sealing structure 404, similarly to the sealing structure 403 described above, O-rings 411, 412, and 413 are arranged in order of increasing outer diameter from the rotating ring 110 side. In this embodiment, the stationary ring 120 includes an annular stationary ring case 130 that is pressed by a spring 307, and the stationary ring 120 and the stationary ring case 130 constitute a stationary ring. The fixed ring case 130 is provided with an inclined surface 131 with which the O-ring 413 is in close contact with each other and the diameter of the inclined surface 131 is reduced in the pressing direction P. The end 302 of the housing 300 is similar to the sealing structure 403 described above. Is provided with an inclined surface 3110. Similarly to the sealing structure 403, inclined surfaces 452 and 462 are provided on the outer peripheral sides of the annular members 450 and 460, respectively, and inclined surfaces 451 and 461 are provided on the inner peripheral sides of the two annular members, respectively. It has been. In the present embodiment, the inclined surfaces 131, 451, and 461 are composed of curved surfaces that are formed so as to substantially follow the outer peripheral surface of the compressed O-ring. On the other hand, the inclined surfaces 452, 462, 3110 are formed of tapered surfaces. Thereby, the function similar to the inclined surface in the above-mentioned sealing structure 400 is exhibited. Further, in the sealing structure 404, the spring 307 is disposed radially inward from the O-ring 411. However, if the stationary ring 120 is sufficiently pressed in the pressing direction P by the restoring force of the O-rings 411, 412, and 413, the spring 307 may not be disposed.

With the above-described configuration, even in the sealing structure 404, each of the O-rings 411, 412, and 413 is compressed in a direction that is not parallel to either the central axis direction or the radial direction. The restoring force due to the compressive deformation can be made to act in both the central axis direction and the radial direction. Therefore, also in the sealing structure 404, the same effect as the above-described sealing structure 400 is exhibited. Also in the sealing structure 404, the number of O-rings and annular members can be increased or decreased as in the other sealing structures described above. Also in the sealing structure 404, the material and shape of each O-ring and each annular member can be changed as appropriate. The fixed ring 120 and the fixed ring case 130 may be integrally formed.

  Here, in the sealing structure 404, as in the sealing structure 400, the outer peripheral side of the seal surface formed between the rotating ring 110 and the fixed ring 120 is the sealing region side B. Therefore, in the sealing structure 404, the right-hand portion in the drawing on the outer peripheral surface of each O-ring is exposed to the sealing region side B. Therefore, the pressure of the sealing fluid acts on each O-ring from the right side to the left side in the drawing. As a result, the stationary ring 120 can be further pressed in the pressing direction P using the pressure of the sealing fluid, so that the sealing surface can be formed more stably. In particular, when the pressure of the sealing fluid is high, the sealing surface 404 can be formed more stably by employing the sealing structure 404. Thus, the arrangement of the plurality of O-rings in the sealing structure according to the present invention may be determined according to the pressure level of the sealing fluid. Further, the arrangement of the plurality of O-rings may be determined according to the type and characteristics of the sealing fluid.

100: mechanical seal 110: rotating ring 120: fixed ring 200: rotating shaft 300: housing 400, 401, 402, 403, 404: sealing structure 411, 412, 413: O-ring 420, 430, 440, 450, 460: annular Member C: Center axis F: Restoring force P: Pressing direction

Claims (7)

A rotating ring fixed to the rotation axis;
A fixed ring that is fixed to a housing having a shaft hole through which the rotary shaft is inserted, and that slides on an end surface of the rotary ring that faces the central axis direction of the rotary shaft;
A mechanical seal comprising:
In the mechanical seal that is fixed to the housing in a state in which the stationary ring is allowed to move in the direction of the central axis and is restricted in rotational movement,
A sealing structure that seals a gap between the housing and the stationary ring while pressing the stationary ring toward the rotating ring;
The sealing structure is
A plurality of O-rings made of rubber-like elastic bodies having different diameters,
Composed of at least one annular member provided one by one between adjacent O-rings,
All of the plurality of O-rings are arranged in a state in which a restoring force due to compressive deformation is applied in both the central axis direction and the radial direction.   The plurality of O-rings are arranged in order from the smallest diameter toward the direction opposite to the pressing direction of the stationary ring, the smallest O-ring is provided in close contact with the stationary ring, and The mechanical seal according to claim 1, wherein an O-ring having the largest diameter is provided in close contact with the housing.   The stationary ring is provided with an inclined surface that is in close contact with the smallest diameter O-ring and expands in the pressing direction of the stationary ring, and the housing has the largest O diameter. The mechanical seal according to claim 2, wherein an inclined surface having a diameter reduced toward a direction opposite to a pressing direction of the stationary ring is provided, which is in close contact with the ring.   On the outer peripheral side of the annular member, there is provided an inclined surface that increases in diameter in the pressing direction of the stationary ring, in which an O-ring having a large diameter of two O-rings adjacent to each other through the annular member is in close contact. In addition, on the inner peripheral side of the annular member, an O-ring having a small diameter of the two adjacent O-rings is in close contact, and the inclination is reduced toward the opposite direction to the pressing direction of the stationary ring. The mechanical seal according to claim 2, wherein a surface is provided.   The plurality of O-rings are arranged in order from the largest in the direction opposite to the pressing direction of the stationary ring, the largest O-ring is provided in close contact with the stationary ring, and The mechanical seal according to claim 1, wherein an O-ring having the smallest diameter is provided in close contact with the housing.   The stationary ring is provided with an inclined surface that is in close contact with the largest diameter O-ring and is reduced in diameter toward the pressing direction of the stationary ring, and the housing has the smallest O diameter. The mechanical seal according to claim 5, further comprising an inclined surface that expands in a direction opposite to a pressing direction of the stationary ring, in which the ring is in close contact.   On the outer peripheral side of the annular member, there is provided an inclined surface that decreases in diameter in the pressing direction of the stationary ring, in which an O-ring having a large diameter of two O-rings adjacent to each other through the annular member is in close contact. In addition, on the inner peripheral side of the annular member, an O-ring having a small diameter among the two adjacent O-rings is in close contact, and the diameter is increased in the direction opposite to the pressing direction of the stationary ring. The mechanical seal according to claim 5 or 6, wherein a surface is provided.

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