Mechanical seal

Abstract

To provide a mechanical seal with high sealing performance. [Solution] One of the sleeve 6 and holder 7 is provided with a recess 64 in which an axially recessed elastic ring 15 can be positioned, and the other of the sleeve 6 and holder 7 is provided with a protrusion 74 that can be inserted into the recess 64 from the axial direction.

Description

Technical Field

[0001] The present invention relates to a mechanical seal, for example, a mechanical seal for shaft-sealing a rotating shaft.

Background Art

[0002] A mechanical seal is used by being mounted between a housing of a fluid device and a rotating shaft arranged to penetrate through the housing. More specifically, a mechanical seal prevents leakage of a sealed fluid by bringing the sliding surface of a stationary seal ring attached to the housing side and the sliding surface of a rotating seal ring attached to the rotating shaft side and rotating together with the rotating shaft into sliding contact in the circumferential direction.

[0003] For example, the mechanical seal disclosed in Patent Document 1 includes a stationary seal ring that is non-rotatably attached to a housing, and a rotating seal ring that is attached to a rotating shaft via a sleeve and a retainer. The sleeve is fixedly attached to the rotating shaft. The retainer holds the rotating seal ring on one end side via an O-ring and a drive pin such that relative rotation is disabled, and the other end side is fixed to the outer diameter side of the sleeve. An annular recess opening to the inner diameter side is formed on the inner peripheral surface of the retainer, and an elastic ring is arranged in the recess. The elastic ring seals the space between the sleeve and the retainer by being clamped in the radial direction between the bottom surface of the recess and the outer peripheral surface of the sleeve.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] However, in the case of a mechanical seal like the one described in Patent Document 1, when the retainer is inserted into the sleeve from the axial direction, the elastic ring is subjected to shear force from both the sleeve and the retainer, causing it to twist, which could reduce the sealing performance between the sleeve and the retainer.

[0006] This invention was made in view of these problems, and aims to provide a mechanical seal with high sealing performance. [Means for solving the problem]

[0007] To solve the aforementioned problems, the mechanical seal of the present invention is: A stationary sealing ring, Rotating sealing ring and A sleeve fixed to the rotating shaft, and a holder fixed to the sleeve and holding the rotating sealing ring, A mechanical seal comprising an elastic ring sandwiched between the sleeve and the holder, One of the sleeve and the holder is provided with a recess that is recessed in the axial direction and into which the elastic ring can be placed, and the other of the sleeve and the holder is provided with a protrusion that can be inserted into the recess from the axial direction. According to this design, the elastic ring is axially clamped between the bottom surface of the recess and the end surface of the convex portion, which reduces the likelihood of twisting of the elastic ring during assembly. Furthermore, the insertion of the convex portion into the recess prevents the sleeve and holder from shifting radially, resulting in a high level of sealing between the sleeve and holder.

[0008] The bottom surface of the recess and the end surface of the protrusion may have at least a portion of an inclined portion that slopes axially from the inner diameter side to the outer diameter side. According to this design, the inclined portion guides the elastic ring to deform in the axial and radial directions, and since the elastic ring is squeezed between the sleeve and the holder in the axial and radial directions, the sealing between the sleeve and the holder is high.

[0009] The inclined portion may have an outer diameter that extends toward the other side of the bottom surface of the recess and the end surface of the protrusion. According to this design, the inclined portion is positioned to cover the outer diameter side of the elastic ring, thereby improving the sealing performance against centrifugal force.

[0010] The inclined portion is provided on the bottom surface of the recess, The recess may be composed of a main body that constitutes one of the sleeve and the holder, and an annular member attached to the main body. According to this, since the recess is a divided structure composed of the main body and the annular member, the inclined part can be manufactured easily.

[0011] The annular member may be provided with the inclined portion. According to this, the inclined section can be constructed simply and with high precision.

[0012] The recess may be provided in the sleeve. According to this design, the annular member is positioned on the outer diameter side of the sleeve, making assembly easier.

[0013] The main body and the annular member may be made of the same material. According to this, since there is little difference in thermal expansion and contraction between the main body and the annular member, the narrow pressure acting on the elastic ring does not change easily.

[0014] The holder may be connected to the sleeve in the axial direction by a connecting member. According to this, the elastic ring can be held between the sleeve and the holder when the connecting members are connected. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view showing a mechanical seal in Example 1 of the present invention. [Figure 2] This is an enlarged view of the main part of Figure 1. [Figure 3] This is an enlarged view of the main part of Figure 2. [Figure 4] It is a schematic diagram illustrating modified examples 1 to 3 of Example 1. [Figure 5] It is a schematic diagram illustrating modified examples 4 and 5 of Example 1. [Figure 6] It is a cross-sectional view illustrating the mechanical seal according to Example 2 of the present invention. [Figure 7] It is a schematic diagram illustrating modified example 6 of Example 2.

Mode for Carrying Out the Invention

[0016] Modes for implementing the mechanical seal according to the present invention will be described below based on working examples.

Examples

[0017] The mechanical seal according to Example 1 will be described with reference to FIG. 1 and FIG. 2. In the following description, the left side of the drawing sheet of FIG. 1 is referred to as the left side, and the right side of the drawing sheet is referred to as the right side.

[0018] The mechanical seal 1 shown in FIG. 1 is for sealing between a rotating shaft 2 and a housing 3 in a fluid device. The mechanical seal 1 of the present Example 1 is a so-called double-type mechanical seal including stationary seal rings 10, 10' and rotating seal rings 20, 20'.

[0019] The mechanical seal 1 is an outside type that seals between inner spaces S1, S1' and an outer space S2 by sliding faces 11, 11', 21, 21'. First fluids F1, F1' as sealed fluids flow into the inner spaces S1, S1', and for example, a second fluid F2 for cooling flows into the outer space S2. The first fluids F1, F1' are partitioned in a sealed manner with a sleeve 6 and a holder 7, which will be described later, interposed therebetween. In the present example, an embodiment is exemplified in which the first fluids F1, F1' are high-pressure liquids, and the second fluid F2 is a liquid having a lower pressure than the first fluids F1, F1'.

[0020] The stationary sealing rings 10, 10' are annular in shape and are provided on the housing 3 of the equipment to be mounted via bellows 5, 5' in a non-rotatable and axially movable manner. The sliding surfaces 11, 11' of the stationary sealing rings 10, 10' are positioned axially opposite to each other and separated to the left and right, and are biased by the bellows 5, 5' in a direction toward each other.

[0021] The rotating sealing rings 20, 20' are annular in shape and are mounted on the rotating shaft 2 via the sleeve 6 and holder 7 so as to be rotatable with the rotating shaft 2. The rotating sealing rings 20, 20' are positioned such that their sliding surfaces 21, 21' face opposite directions in the axial direction and are axially facing the sliding surfaces 11, 11'.

[0022] The bellows 5, 5' bias the stationary sealing rings 10, 10' in the axial direction, causing the sliding surfaces 11, 11' of the stationary sealing rings 10, 10' and the sliding surfaces 21, 21' of the rotating sealing ring 20 to slide in close contact with each other.

[0023] The stationary sealing ring 10 and the rotating sealing ring 20 are typically formed from two SiC (hard material) components or a combination of SiC (hard material) and carbon (soft material), but are not limited to these; any sliding material used for mechanical seals is applicable. SiC can be sintered using boron, aluminum, carbon, etc., as sintering aids, or from materials consisting of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction-sintered SiC made of SiC and Si, SiC-TiC, SiC-TiN, etc. Carbon can be a mixture of carbonaceous and graphite, as well as resin-molded carbon and sintered carbon. In addition to the above-mentioned sliding materials, metal materials, resin materials, surface modification materials (coating materials), composite materials, etc., are also applicable.

[0024] As shown in Figures 1 and 2, the sleeve 6 comprises a sleeve body 61, which is made of a metal such as stainless steel, and an annular member 62 positioned on the outer diameter side of the sleeve body 61. After the sleeve body 61 is fitted onto the rotating shaft 2, its right end is fixed to the rotating shaft 2 by a set screw (not shown) so that it cannot rotate relative to the rotating shaft 2 and cannot move relative to the axial direction.

[0025] As shown in Figure 2, an annular protrusion 61A is formed to the right of the left end of the sleeve body 61, extending outwards. An annular stepped portion 63 is formed at the left end of the sleeve body 61, opening to the left and outwards. Specifically, the stepped portion 63 is composed of the outer peripheral surface 61a of the left end of the sleeve body 61, i.e., the area to the left of the protrusion 61A on the sleeve body 61, and the left surface 61Aa of the protrusion 61A.

[0026] The annular member 62 is made of the same material as the sleeve body 61, such as stainless steel or other metal. The annular member 62 has a roughly inverted L-shape in cross-section, with an annular vertical portion 62a and a cylindrical horizontal portion 62b extending to the left from the outer diameter side of the vertical portion 62a.

[0027] The inner diameter of the vertical portion 62a is slightly larger than the outer circumferential surface 61a of the sleeve body 61. This allows the annular member 62 to be inserted into the outer diameter side of the stepped portion 63 of the sleeve body 61.

[0028] When the annular member 62 is positioned on the stepped portion 63 of the sleeve body 61, the right surface 62f of the vertical portion 62a abuts against the left surface 61Aa of the protruding portion 61A to position it, and an annular recess 64 is formed in the sleeve 6 by the sleeve body 61 and the annular member 62, which is recessed to the right in the axial direction.

[0029] The annular recess 64 is configured to open to the left side due to the outer peripheral surface 61a of the sleeve body 61, the inclined surface 64a as an inclined portion, and the inner peripheral surface 62c of the horizontal portion 62b.

[0030] As shown in Figures 2 and 3, the inclined surface 64a constitutes the bottom surface of the annular recess 64. The inclined surface 64a is obliquely inclined between the inner circumferential surface 62d of the vertical portion 62a and the inner circumferential surface 62c of the horizontal portion 62b. Specifically, the inclined surface 64a extends from the inner circumferential surface 62d of the vertical portion 62a toward the inner circumferential surface 62c of the horizontal portion 62b, inclining to the left. In other words, the outer diameter side of the inclined surface 64a is located to the left of the inner diameter side.

[0031] Furthermore, the left inner edge of the horizontal section 62b is an inclined surface 62e that widens to the left from the inner circumferential surface 62c of the horizontal section 62b.

[0032] Returning to Figures 1 and 2, the holder 7 is made of a material with a coefficient of thermal expansion similar to that of the rotating sealing rings 20, 20', such as a nickel alloy. The holder 7 has a radially extending annular base portion 71, a cylindrical holding portion 72 extending to the right from the outer diameter side of the base portion 71, a cylindrical holding portion 73 extending to the left from the outer diameter side of the base portion 71, and a cylindrical convex portion 74 as a convex portion extending to the right from the inner diameter side of the base portion 71 compared to the holding portion 72.

[0033] The holder 7 is externally fitted onto the rotating shaft 2. The holder 7 is fixed from the left side to the left end of the sleeve body 61 by a bolt 9, which is a connecting member extending in the axial direction, at a position on the inner diameter side of the base portion 71.

[0034] The rotating sealing ring 20 is held on the inner diameter side of the holding portion 72 via the secondary seal 12.

[0035] The rotating sealing ring 20' is held on the inner diameter side of the holding portion 73 via the secondary seal 13. The rotating sealing ring 20' is prevented from coming off to the left by a retaining member 14 attached to the outer diameter side of the holder 7.

[0036] The cylindrical projection 74 is positioned on the outer diameter side of the outer peripheral surface 61a of the sleeve body 61, and the right end of the cylindrical projection 74 is located within the annular recess 64 of the sleeve 6. The right end surface 74a of the cylindrical projection 74 is a vertical surface.

[0037] As shown in Figure 3, when the cylindrical protrusion 74 is inserted into the annular recess 64 of the sleeve 6, the outer edge of the right end face 74a is guided by the inclined surface 62e of the annular member 62, so that it can be smoothly inserted into the annular recess 64 of the sleeve 6.

[0038] Furthermore, the outer diameter of the cylindrical projection 74 is slightly smaller than the inner diameter of the horizontal portion 62b. When the cylindrical projection 74 and the annular member 62 are tilted or shifted radially, the outer surface 74b of the cylindrical projection 74 and the inner surface 62c of the horizontal portion 62b come into contact, thereby restricting the relative tilt and radial shift between the cylindrical projection 74 and the annular member 62.

[0039] As shown in Figures 2 and 3, an O-ring 15, which is an elastic ring made of rubber or synthetic resin, is sandwiched between the sleeve 6 and the holder 7, and the O-ring 15 seals the space between the sleeve 6 and the holder 7, that is, the space between the left and right inner spaces S1 and S1'.

[0040] When the holder 7 is fixed to the sleeve 6 by the bolt 9, the O-ring 15 is axially sandwiched between the annular recess 64 of the sleeve 6 and the cylindrical protrusion 74 of the holder 7. Therefore, during assembly, opposing axial forces are less likely to act on the outer and inner diameter sides of the O-ring 15, making twisting less likely.

[0041] More specifically, when the holder 7 moves to the right relative to the sleeve 6, the cylindrical projection 74 presses the O-ring 15 to the right, and it is pressed axially against the inclined surface 64a of the annular member 62. The O-ring 15 deforms radially due to the reaction force from the inclined surface 64a and is pressed against the inner circumferential surface 62c of the horizontal portion 62b and the outer circumferential surface 61a of the sleeve body 61. In other words, the elastic restoring force of the O-ring 15 acts axially and radially between the sleeve 6 and the holder 7, thereby improving the sealing performance between the sleeve 6 and the holder 7.

[0042] Furthermore, when the holder 7 is fixed to the sleeve 6 by the bolt 9, as described above, the cylindrical protrusion 74 is inserted into the annular recess 64, which prevents relative tilting or radial displacement between the sleeve 6 and the holder 7 due to vibration or centrifugal force of the rotating shaft 2. Therefore, the airtight seal between the sleeve 6 and the holder 7 can be maintained.

[0043] Furthermore, the inclined surface 64a extends from the inner diameter side to the outer diameter side, that is, towards the cylindrical protrusion 74 side. As a result, the inclined surface 64a is positioned to cover the outer diameter side of the O-ring 15, so even if centrifugal force acts on the O-ring 15, the inclined surface 64a makes it easier to deform the O-ring 15 toward the inner diameter side, and the airtight seal between the sleeve 6 and the holder 7 can be maintained.

[0044] Furthermore, the inclined surface 64a extends from the inner circumferential surface 62d of the vertical portion 62a while inclining to the left, and the corner formed by the inclined surface 64a and the outer circumferential surface 61a of the sleeve body 61 is acute. As a result, the O-ring 15 can be significantly compressed in the axial and radial directions at the corner between the inclined surface 64a and the outer circumferential surface 61a of the sleeve body 61, improving the sealing performance.

[0045] Furthermore, the annular recess 64 is a divided structure composed of a sleeve body 61 and an annular member 62. This allows for the provision of an inclined surface 64a on the annular member 62, making it easy to form the inclined surface 64a.

[0046] Furthermore, the annular member 62 is positioned such that the right surface 62f of the vertical portion 62a abuts against the left surface 61Aa of the protruding portion 61A, and since the annular member 62 is provided with an inclined surface 64a, the annular recess 64 and the inclined surface 64a can be constructed simply and accurately.

[0047] Furthermore, the annular recess 64 is provided in the sleeve 6. In other words, since the annular member 62 is positioned on the outer diameter side of the sleeve body 61, the assembly of the mechanical seal 1 is simplified.

[0048] Furthermore, since the holder 7 is axially connected to the sleeve body 61 by a bolt 9, the O-ring 15 can be easily and accurately clamped between the sleeve body 61 and the holder 7 when the bolt 9 is connected.

[0049] Furthermore, since the sleeve body 61 and the annular member 62 are made of the same material, differences in thermal expansion and contraction between the sleeve body 61 and the annular member 62 are less likely to occur, and the narrow pressure acting on the O-ring 15 is less likely to change due to temperature changes in the external environment.

[0050] In the mechanical seal 1 of this embodiment, a second cooling fluid F2 is introduced and circulated into the outer space S2 from the outside. This can cause a difference in thermal expansion and contraction between the holder 7 facing the outer space S2 and the sleeve 6 facing the inner space S1. For example, the sleeve 6 may expand due to thermal expansion relative to the holder 7, which may increase the radial gap between the cylindrical protrusion 74 and the annular recess 64. However, since the annular recess 64 will be closer to the cylindrical protrusion 74 in the axial direction, the O-ring 15 will be compressed and deformed radially, thus maintaining its sealing performance. Furthermore, when the cooling fluid flows into the inner spaces S1 and S1', the holder 7 may expand or contract relative to the sleeve 6.

[0051] Furthermore, the holder 7 and the rotating sealing rings 20, 20' facing the outer space S2 are made of materials with similar coefficients of thermal expansion. This makes it difficult for differences in thermal expansion and contraction to occur between the holder 7 and the rotating sealing rings 20, 20', thus preventing slurries and foreign matter from getting stuck due to a larger gap between the holder 7 and the rotating sealing rings 20, 20'.

[0052] In this embodiment, the protrusion is shown as being integrated with the holder, but the protrusion may also be made of a separate component from the holder.

[0053] Furthermore, in this embodiment, the recess was composed of a sleeve and an annular member, but the recess may be integrally formed in the sleeve. In other words, the recess does not have to be a divided structure.

[0054] Furthermore, in this embodiment, the inclined surface 64a was formed in a straight line from the inner circumferential surface 62d of the vertical portion 62a of the annular member 62 to the inner circumferential surface 62c of the horizontal portion 62b, but this is not limited to this.

[0055] For example, as shown in Figure 4(a), the bottom surface 641A of the annular recess 641 in Modified Example 1 may consist of a vertical surface 641b extending radially from the inner circumferential surface 621d of the vertical portion 621a of the annular member 621, and an inclined surface 641a extending from the outer circumferential end of the vertical surface 641b to the inner circumferential surface 621c of the horizontal portion 621b, tilting to the left. In this Modified Example 1 as well, the O-ring 15 can be held between the cylindrical protrusion 74 and the annular recess 641 in the axial and radial directions. The vertical surface 641b may be inclined at a different angle than the inclined surface 641a.

[0056] Furthermore, as shown in Figure 4(b), the bottom surface 642A of the annular recess 642 in Modified Example 2 may consist of an inclined surface 642a extending from the inner circumferential surface 622d of the vertical portion 622a of the annular member 622 while tilting to the left, and a vertical surface 642b extending from the outer diameter end of the inclined surface 642a toward the inner circumferential surface 622c of the horizontal portion 622b. In this Modified Example 2 as well, the O-ring 15 can be held between the cylindrical protrusion 74 and the annular recess 642 in the axial and radial directions. Note that the vertical surface 642b may be inclined at a different angle than the inclined surface 642a.

[0057] Furthermore, as shown in Figure 4(c), the bottom surface of the annular recess 643 in Modified Example 3, i.e., the inclined surface 643a, may have a curved shape that protrudes to the left. In this Modified Example 3 as well, the O-ring 15 can be held between the cylindrical protrusion 74 and the annular recess 643 in the axial and radial directions. Note that the inclined surface 643a may be curved only in part.

[0058] In the above embodiment 1, a configuration in which an inclined surface 64a is formed on the annular member 62 was illustrated, but the embodiment is not limited to this. For example, as shown in Figure 5(a), the left side of the protruding portion 614A of the sleeve body 614 in modified example 4 may be an inclined surface 644a. In this case, the annular member 624 is fitted onto the left outer edge of the protruding portion 614A and constitutes the outer diameter portion of the annular recess 644. As a result, the annular member 624 is restricted from moving radially and axially to the right relative to the sleeve body 614.

[0059] Furthermore, as shown in the modified example 5 in Figure 5(b), the right end surface 745a of the cylindrical projection 745 may extend while inclined to the right from the inner diameter end to the outer diameter end. This allows the O-ring 15 to be clamped in the axial and radial directions by the inclined surface 64a of the annular recess 64 and the right end surface 745a of the cylindrical projection 745. In addition, a part of the right end surface of the cylindrical projection 745 may be an inclined surface. Moreover, in this case, the bottom surface of the annular recess may be a vertical surface instead of an inclined surface. [Examples]

[0060] Next, the mechanical seal according to Example 2 will be described with reference to Figure 6. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0061] As shown in Figure 6, in this embodiment 2, the mechanical seal 200 has an annular recess 210 as a recess formed by the holder 27 and the sleeve body 261, and an annular member 262 as a protrusion is provided on the sleeve 26.

[0062] Specifically, the holder 27 has an annular groove 275 formed on the inner diameter side of the base portion 271. The groove 275 opens to the right and on the inner diameter side, and can be fitted onto the large diameter portion 261a provided at the left end of the sleeve body 261. The holder 27 is fixed to the left end of the sleeve body 261 from the left side by a bolt 9.

[0063] Furthermore, an annular stepped portion 276 is formed on the outer diameter side of the groove 275 in the base portion 271, opening to the right and inner diameter sides. The stepped portion 276 consists of an end face 276a extending perpendicularly from the inner circumferential surface of the groove 275 toward the outer diameter side, a circumferential surface 276b extending horizontally to the right from the outer diameter end of the end face 276a, and a tapered surface 276c that widens in diameter from the right end of the circumferential surface 276b toward the right end face of the base portion 271.

[0064] The annular recess 210 is formed by opening to the right side through the large-diameter portion 261a of the sleeve body 261 and the stepped portion 276 of the holder 27. In other words, the holder 27 may constitute only a part of the recess, or a part of the sleeve 26 may constitute the rest of the recess.

[0065] The sleeve 26 consists of a sleeve body 261 and an annular member 262 that is attached to the outer diameter side of the sleeve body 261 so as to protrude.

[0066] The sleeve body 261 has a large-diameter portion 261a at its left end and a small-diameter portion 261b located to the right of the large-diameter portion 261a. The small-diameter portion 261b has an annular groove 261c that opens to the outer diameter side. A regulating member 216 with a rectangular cross-section is placed in the groove 261c.

[0067] The restricting member 216 has a roughly C-shape in axial view and extends in the circumferential direction. The outer circumferential surface of the restricting member 216 is positioned on the outer diameter side of the outer circumferential surface of the small diameter portion 261b.

[0068] The annular member 262 comprises a first step portion 265, a second step portion 266, and a third step portion 267. The first step portion 265 is provided in an annular shape on the left inner diameter portion of the annular member 262, opening to the left and inner diameter sides. The second step portion 266 is provided in an annular shape on the right inner diameter portion of the annular member 262, opening to the right and inner diameter sides. The third step portion 267 is provided in an annular shape on the right outer diameter portion of the annular member 262, opening to the right and outer diameter sides.

[0069] The annular member 262 is fitted onto the small-diameter portion 261b of the sleeve body 261. The first stage portion 265 of the annular member 262 is fitted onto the large-diameter portion 261a of the sleeve body 261. The second stage portion 266 of the annular member 262 is fitted onto the left outer edge of the regulating member 216.

[0070] Furthermore, the left end surface of the annular member 262 is an inclined surface 262a that extends from the inner diameter side to the outer diameter side, sloping to the left. The left end of the annular member 262 is positioned within the annular recess 210, and thus constitutes a convex portion.

[0071] An O-ring 15 is sandwiched in the axial direction between the end face 276a of the holder 27 and the inclined surface 262a of the annular member 262.

[0072] Specifically, when the holder 27 is fixed to the sleeve body 261 by the bolt 9, the end face 275a of the holder 27 presses the O-ring 15 to the right and presses it against the inclined surface 262a of the annular member 262. The O-ring 15 deforms radially due to the reaction force from the inclined surface 262a and is pressed against the circumferential surface 276b of the stepped portion 276 and the outer circumferential surface of the large diameter portion 261a of the sleeve body 261. In other words, since the O-ring 15 is squeezed axially and radially between the sleeve 26 and the holder 27, the sealing performance between the sleeve 26 and the holder 27 can be improved.

[0073] When the annular member 262 is inserted into the annular recess 210, its outer edge is guided by the tapered surface 276c of the holder 27, allowing the annular member 262 to be smoothly inserted into the annular recess 210.

[0074] Furthermore, since the annular member 262 that is fitted onto the small-diameter portion 261b of the sleeve body 261 is provided with an inclined surface 262a, the inclined surface 262a can be easily constructed.

[0075] Furthermore, the groove 261c and the regulating member 216 are not limited to being formed in a substantially annular shape, but may be arranged in multiples in the circumferential direction.

[0076] Furthermore, although the protrusion was formed by an annular member 262 fixed to the sleeve body 261, the protrusion may be integrally provided with the sleeve.

[0077] Furthermore, in this embodiment, the annular recess 210 is shown as being composed of the large-diameter portion 261a of the sleeve body 261 and the stepped portion 276 of the holder 27, but the holder may also have an integrally provided recess that is recessed in the axial direction. In other words, the recess does not have to be a divided structure.

[0078] Furthermore, as shown in the modified example 6 in Figure 7, the bottom surface of the annular recess 210' may be an inclined portion 210a'. In this case, the inclined portion 210a' can be easily constructed by attaching the annular member 278' having the inclined portion 210a' to the stepped portion 276' of the holder 27'. Also, in this modified example 6, the end surface 262a' of the annular member 262' is shown to be vertical, but it may be an inclined surface 262a as in Example 2.

[0079] Although embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments, and any changes or additions that do not depart from the spirit of the present invention are also included.

[0080] For example, while the above embodiments 1 and 2 described outside-type mechanical seals, they may also be applied to inside-type mechanical seals. Furthermore, the mechanical seal is not limited to a double type; it may be freely changed to a single type, tandem type, etc.

[0081] Furthermore, although the fluid in the internal space was described as a high-pressure liquid in Examples 1 and 2, it is not limited to this and may be a gas or a low-pressure liquid, or it may be a mist-like mixture of liquid and gas.

[0082] Furthermore, although the fluid in the outer space was described as a low-pressure liquid in Examples 1 and 2 above, it is not limited to this and may be a liquid or a high-pressure gas, or a mist-like mixture of liquid and gas.

[0083] Furthermore, in the above-described embodiments 1 and 2, the inner space side was described as the high-pressure side and the outer space side as the low-pressure side. However, the inner space side may be the low-pressure side and the outer space side may be the high-pressure side, or the pressures of the outer space side and the inner space side may be approximately the same.

[0084] Furthermore, while embodiments 1 and 2 illustrate a configuration in which one of the bottom surface of the recess and the end surface of the convex portion is an inclined portion that slopes relative to the other, the invention is not limited to this configuration, and the bottom surface of the recess and the end surface of the convex portion may be parallel to each other in the axial direction.

[0085] Furthermore, although the terms "vertical" and "horizontal" were used in the above-mentioned Examples 1 and 2, some degree of distortion or tilt is acceptable.

[0086] Furthermore, although the elastic ring was described as an O-ring 15 in Examples 1 and 2 above, it is not limited to this, and can be freely changed to a rectangular cross-section, an elliptical cross-section, an X-shaped cross-section, etc. [Explanation of Symbols]

[0087] 1 Mechanical seal 2 rotation axes 3 Housing 6 sleeves 7 Holder 9. Bolts (connecting members) 10,10' static sealing ring 15 O-rings (elastic rings) 20,20' Rotating sealing ring 61 Sleeve body (body) 62 Annular member 64 Annular recess (recess) 64a Inclined surface (bottom surface of recess, inclined part) 74. Cylindrical protrusion (protrusion) 74a Right end face (end face) F1,F1' 1st fluid F2 2nd fluid S1,S1' inner space S2 outside space

Claims

1. A stationary sealing ring, Rotating sealing ring and A sleeve fixed to the rotating shaft, and a holder fixed to the sleeve and holding the rotating sealing ring, A mechanical seal comprising an elastic ring sandwiched between the sleeve and the holder, A mechanical seal comprising a sleeve and a holder, one of which is provided with a recess in the axial direction in which the elastic ring can be positioned, and the other of the sleeve and the holder, provided with a protrusion that can be inserted into the recess from the axial direction.

2. The mechanical seal according to claim 1, wherein at least a portion of the bottom surface of the recess and the end surface of the protrusion have an inclined portion that slopes axially from the inner diameter side to the outer diameter side.

3. The mechanical seal according to claim 2, wherein the inclined portion extends toward the other side of the bottom surface of the recess and the end surface of the convex portion on its outer diameter side.

4. The inclined portion is provided on the bottom surface of the recess, The mechanical seal according to claim 2, wherein the recess is composed of a main body constituting one of the sleeve and the holder, and an annular member attached to the main body.

5. The mechanical seal according to claim 4, wherein the inclined portion is provided on the annular member.

6. The mechanical seal according to claim 4, wherein the recess is provided in the sleeve.

7. The mechanical seal according to claim 4, wherein the main body and the annular member are made of the same material.

8. The mechanical seal according to any one of claims 1 to 7, wherein the holder is axially connected to the sleeve by a connecting member.

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