Mechanical seal

Abstract

The present invention provides a mechanical seal which does not deform the sliding surface of the sealing ring and is difficult to damage the retainer. The mechanical seal (1) comprises a pair of sealing rings (10, 20) which rotate relatively and a retainer (11) which retains the sealing ring (10). The retainer (11) comprises an annular base (11a), an annular retaining portion (11c) which fits with the outer periphery of the sealing ring (10), and an annular connecting portion (11b) which connects the base (11a) and the annular retaining portion (11c) in the axial direction. An annular space (S) surrounded by the base (11a), the annular connecting portion (11b) and the annular retaining portion (11c) is formed between the outer periphery of the sealing ring (10) and the inner periphery of the retainer (11). In the annular space (S), a beam (110) which connects the base (11a) and the annular retaining portion (11c) is formed on the retainer (11).

Description

Technical Field

[0001] The invention relates to a mechanical seal for sealing a rotating shaft. Background Art

[0002] Conventional mechanical seals seal the gap between a housing and a rotating shaft by causing a stationary seal ring fixed to a housing and a rotating seal ring fixed to a rotating shaft and rotating together with the rotating shaft to rotate relative to each other.

[0003] For example, in conventional mechanical seals, a rotating seal ring is fixed to a rotating shaft via a retainer. The retainer retains the rotating seal ring by a so-called shrink-fit, where the retainer is heated and expanded, and then the rotating seal ring is inserted. The retainer is cooled and shrunk, and an annular retaining portion protruding from the inner circumference of the retainer toward the inner diameter side is fitted to the outer circumference of the rotating seal ring. Since the inner circumference of the retaining portion is pressed against the outer circumference of the rotating seal ring, the sealing between the rotating seal ring and the retainer can be ensured without using a secondary seal such as an O-ring.

[0004] Furthermore, in the case where the rotary seal ring is made of a plastic material such as ceramic, if the contact pressure of the retaining portion that contacts the outer periphery of the rotary seal ring during shrink fitting is locally large, there is a risk of damage to the rotary seal ring or deformation of the sliding surface. Therefore, in the mechanical seal of Patent Document 1, the retaining portion is brought into large contact with the outer periphery of the rotary seal ring along the axial direction, so that the contact pressure acts approximately evenly throughout the contact range.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: U.S. Patent Application Publication No. 2007 / 210526 (page 3, Figure 1 , Figure 5 ).

[0008] However, in the mechanical seal of Patent Document 1, the retainer holding portion is structured such that the retainer holding portion is connected to the base end material of the bellows fixed by welding through an annular connecting portion extending in the axial direction from the outer diameter side of the retainer. The fitting force of the retainer to the outer periphery of the rotating seal ring is designed according to the difference between the inner diameter of the retainer before shrink fitting and the outer diameter of the rotating seal ring. When the mechanical seal is used, when the annular connecting portion is deformed by the pressure of the sealed fluid, the retainer will further move from the shrink fitting state and the fitting force will become too large, which may cause not only the sliding surface of the rotating seal ring to be deformed, but also the retainer to be damaged. Summary of the invention

[0009] The present invention has been made in view of such problems, and an object of the present invention is to provide a mechanical seal in which the sliding surface of the seal ring does not deform and the retainer is not easily damaged.

[0010] In order to solve the above-mentioned problem, the mechanical seal of the present invention comprises a pair of relatively rotating sealing rings and a retaining ring for retaining at least one sealing ring, wherein the retaining ring comprises: an annular base; an annular retaining portion fitted with the outer periphery of the sealing ring; and an annular connecting portion axially connecting the base and the annular retaining portion, wherein an annular space surrounded by the base, the annular connecting portion and the annular retaining portion is formed between the outer periphery of the sealing ring and the inner periphery of the retaining ring.

[0011] In the annular space, a beam connecting the base portion and the annular holding portion is formed on the retainer.

[0012] Thus, by forming a beam connecting the base of the guard ring and the annular retaining portion in the annular space on the inner diameter side of the annular connecting portion, the structural strength of the annular connecting portion can be improved, and the displacement of the annular retaining portion caused by the bending action of the annular connecting portion can be limited. Therefore, when the mechanical seal is used, the influence of the pressure of the sealed fluid on the fitting force of the annular retaining portion can be suppressed, the sliding surface of the sealing ring will not be deformed, and the guard ring can be prevented from being damaged.

[0013] It is also possible that the beams are equidistant in the circumferential direction.

[0014] Thus, by providing beams at equal intervals in the circumferential direction, the structural strength of the annular connection portion can be uniformly increased along the circumferential direction, and displacement of the annular holding portion can be reliably restricted.

[0015] The beam may be formed so as to separate the annular space into inner and outer parts in a radial direction.

[0016] Thus, the annular connecting portion located on the outer diameter side of the annular space separated radially outward by the beam is easily deformed, displacement of the annular holding portion is restricted, the fitting force of the annular holding portion is appropriately maintained, and deformation of the sliding surface of the seal ring is suppressed.

[0017] Alternatively, the beam may be integrally formed of the same material as the base.

[0018] Thereby, the thermal expansion and contraction of the beam can be matched with the thermal expansion and contraction of the base during shrink fit, and the fitting force of the annular holding portion can be stabilized.

[0019] The annular holding portion may extend radially inward from the annular connecting portion and further extend axially toward the base portion.

[0020] Thus, by causing the front end of the retaining portion to go around the radially inner side of the annular space and approach the base, the annular space on the outer diameter side is arranged close to the axial annular retaining portion side, so that the bending effect of the annular connecting portion can be fully exerted.

[0021] Alternatively, the bellows may be fixedly welded to the base.

[0022] Thus, since the base end material of the bellows fixed by welding and the retainer can be integrally structured, no joint portion is formed in the retainer, and the structural strength can be improved.

[0023] Alternatively, the retaining ring is integrally formed by a three-dimensional shaping device.

[0024] Thereby, the annular space or the beam formed in the retainer can be simply configured. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a longitudinal sectional view showing an example of a mechanical seal in an embodiment of the present invention.

[0026] Figure 2 It is an enlarged cross-sectional view showing a retainer and a stationary seal ring in the embodiment.

[0027] exist Figure 3 In (a), it is along Figure 2 The AA section extending along the radial direction in (b) is a cross-sectional view along Figure 2 BB cross-section extending in the circumferential direction.

[0028] Figure 4 It is a cross-sectional view showing a modified example of the retainer in the embodiment.

[0029] Figure 5 It is a cross-sectional view showing a modified example of the retainer in the embodiment.

[0030] Figure 6 It is a cross-sectional view showing a modified example of the retainer and the stationary seal ring in the embodiment. DETAILED DESCRIPTION

[0031] Modes for implementing the mechanical seal according to the present invention will be described below based on examples.

[0032] Example

[0033] For the mechanical seal involved in the embodiment, refer to Figures 1 to 3 In addition, in this embodiment, the inner diameter side of the rotating seal ring and the stationary seal ring constituting the mechanical seal is described as the leakage side, that is, the atmosphere side (low pressure side), and the outer diameter side is described as the sealed fluid side (high pressure side).

[0034] Figure 1The mechanical seal 1 for general industrial machinery is a built-in type, which seals the sealed liquid that is intended to leak from the outer diameter side of the sliding surface to the inner diameter side, and is mainly composed of a rotating seal ring 20 and a stationary seal ring 10. The rotating seal ring 20 is annular, and as a seal ring, it can be set in a state where the rotating shaft 2 rotates together with the sleeve 3 fixed to the rotating shaft 2. The stationary seal ring 10 is annular, and as a seal ring, it is set in a non-rotating state and axially movable state on the sealing cover 5 fixed to the housing 4 of the installed equipment. The stationary seal ring 10 is axially forced by the bellows 6, so that the sliding surface 10a of the stationary seal ring 10 and the sliding surface 20a of the rotating seal ring 20 slide closely against each other. In addition, for the bellows 6, one axial end is welded and fixed to the metal retainer 11 that holds the stationary seal ring 10, and the other axial end is welded and fixed to the metal hoop 12 that is fixed integrally with the sealing cover 5 by the bolt 50.

[0035] The stationary seal ring 10 and the rotating seal ring 20 are typically formed by a combination of SiC (hard material) or SiC (hard material) and carbon (soft material), but are not limited to this. The sliding material can be used as a sliding material for mechanical seals. Among them, as SiC, a sintered body with boron, aluminum, carbon, etc. as a sintering aid is represented, and there are materials composed of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction sintered SiC, SiC-TiC, SiC-TiN, etc. composed of SiC and Si. As carbon, carbon mixed with carbon and graphite is represented, and resin-formed carbon, sintered carbon, etc. can be used. In addition, in addition to the above-mentioned sliding materials, metal materials, resin materials, surface modification materials (coating materials) or composite materials can also be used. Furthermore, in addition, in the case of using a highly corrosive fluid as the sealed fluid, a highly corrosion-resistant material such as a nickel-based superalloy can also be used.

[0036] like Figure 1 As shown, the rotary seal ring 20 is formed in a substantially L-shaped cross-sectional view, and is retained by inserting and fitting the inner circumference of a substantially cylindrical retainer 21 integrally fixed to the sleeve 3 by bolts 30, with an O-ring 22 sandwiched therebetween. In addition, the O-ring 22 functions as a secondary seal to ensure the sealing performance between the rotary seal ring 20 and the retainer 21. In addition, the rotary seal ring 20 can rotate together with the rotating shaft 2 by inserting a stop pin 23 extending in the axial direction from the retainer 21 into a recess 20b formed on the axially opposite side of the sliding surface 20a.

[0037] like Figure 2As shown in FIG. 1 , the stationary seal ring 10 is formed in a substantially rectangular cross-sectional view, and the outer diameter sides of the sliding surface 10a and the back surface 10b on the opposite side in the axial direction are in contact with the inner side surface 11d of the substantially cylindrical retainer 11 in the axial direction, and the annular retaining portion 11c of the retainer 11 is fitted in the substantially axial center of the outer peripheral surface 10c to retain the stationary seal ring 10. The retainer 11 is held by the stationary seal ring 10 by, for example, so-called shrink fitting, where the retainer 11 that is heated and thermally expanded is inserted into the stationary seal ring 10, and the retainer 11 is cooled and shrunk in the state where the back surface 10b is in contact with the inner side surface 11d of the retainer 11 in the axial direction, thereby fitting the annular retaining portion 11c to the outer peripheral surface 10c of the stationary seal ring 10. As a result, since the inner peripheral surface 11e of the annular retaining portion 11c is pressed against the outer peripheral surface 10c of the stationary seal ring 10, the sealing performance between the stationary seal ring 10 and the retainer 11 can be ensured without using a secondary seal such as an O-ring. In addition, the back surface 10b of the stationary seal ring 10 and the inner side surface 11d of the retainer 11 abut in the axial direction, thereby stabilizing the axial position of the stationary seal ring 10 relative to the retainer 11 during shrink fitting or use. Figure 2 In the figure, for the convenience of explanation, the bellows 6 fixed to the retainer 11 by welding is omitted.

[0038] Next, the structure of the retaining ring 11 is described in detail. Figure 2 as well as Figure 3 As shown, the guard ring 11 is substantially L-shaped in cross-sectional view, and has an annular base portion 11a, an annular connecting portion 11b, and an annular retaining portion 11c. An annular space S surrounded by the base portion 11a, the annular connecting portion 11b, and the annular retaining portion 11c is formed on the inner periphery of the guard ring 11. In the annular space S, a plurality of beams 110 connecting the base portion 11a and the annular retaining portion 11c in the axial direction are equidistantly spaced in the circumferential direction (especially referring to Figure 3 ). In addition, the retainer 11 is integrally formed using the same material using a three-dimensional forming device, such as a 3D printer. Furthermore, in addition, the annular space S becomes a substantially blocked space in a state where the retainer 11 holds the stationary seal ring 10.

[0039] The base portion 11a has an inner side surface 11d that contacts the back surface 10b of the stationary seal ring 10 and one axial end side, and an annular extension portion 11f that extends axially on the outer diameter side of the inner side surface 11d, and has a fixing portion 11g that is welded and fixed to one axial end of the bellows 6 at the other axial end side. In addition, the annular extension portion 11f has a tapered surface 11h that is inclined toward the outer radial direction formed on one axial end side of its inner circumference, and is in a cross-sectional view. Figure 5 Edge shape.

[0040] The annular connecting portion 11b extends axially from one axial end of the annular extending portion 11f in the base portion 11a. In addition, the annular connecting portion 11b is thinner than the annular extending portion 11f, and is easy to bend during shrink fitting or due to the pressure of the sealed fluid when the mechanical seal is used.

[0041] The annular retaining portion 11c extends from the free end of the axial end of the annular connecting portion 11b to the inner diameter side, bends to the base 11a side and extends along the axial direction, thereby forming a substantially L-shaped cross-sectional view. In addition, the annular retaining portion 11c has a tapered surface 11k inclined toward the inner radial direction in a manner substantially parallel to the tapered surface 11h of the annular protruding portion 11f formed at the front end on the base 11a side. In addition, at the front end on the base 11a side of the annular retaining portion 11c, an inner side surface 11m is formed that extends from the inner diameter end of the tapered surface 11k toward the inner radial direction and is orthogonal to the inner peripheral surface 11e of the annular retaining portion 11c.

[0042] The beam 110 extends in the axial direction so as to connect a virtual conical surface obtained by extending the conical surface 11k at the front end of the annular holding portion 11c in the circumferential direction and a virtual conical surface obtained by extending the conical surface 11h of the annular extending portion 11f of the base portion 11a in the circumferential direction. Figure 3 As shown in (a), the beam 110 is formed as a columnar body having a substantially rectangular shape in a cross-sectional view by means of an inner peripheral surface 110a, an outer peripheral surface 110d, and two side surfaces 110b and 110c extending in the radial direction. In addition, the inner peripheral surface 110a of the beam 110 is formed as a plane extending in the axial direction on the base 11a side from the inner diameter end of a virtual conical surface obtained by extending the conical surface 11k in the circumferential direction toward the inner diameter end of a virtual conical surface obtained by extending the conical surface 11h in the circumferential direction. In addition, the outer peripheral surface 110d of the beam 110 is formed as an L-shaped curved surface extending in the outer diameter side toward the outer diameter end of the virtual conical surface obtained by extending the conical surface 11h in the circumferential direction after extending in the axial direction from the outer diameter end of the virtual conical surface obtained by extending the conical surface 11k in the circumferential direction toward the base 11a side. In addition, the radially inner and outer surfaces 110 a and 110 d of the beam 110 may be curved along the circumferential direction.

[0043] In addition, on the outer diameter side of the beam 110, that is, inside the retaining ring 11, a first annular space S1 is formed which is surrounded by the annular connecting portion 11b, the annular retaining portion 11c, and the surface 110d on the outer peripheral side of the beam 110. In addition, between the inner diameter side of the beam 110, that is, the outer peripheral surface 10c of the stationary sealing ring 10 retained on the inner diameter side of the retaining ring 11, a second annular space S2 is formed which is surrounded by the base 11a, the inner side surface 11m of the annular retaining portion 11c, and the surface 110a on the inner peripheral side of the beam 110. In addition, the first annular space S1 and the second annular space S2 are connected by connecting holes 111 formed between the beams 110 which are equidistant along the circumferential direction. In other words, the annular space S is separated radially inside and outside by a plurality of beams 110 into the first annular space S1 and the second annular space S2. In addition, the first annular space S1 and the second annular space S2 are constructed so that the axial length is substantially the same (especially refer to Figure 2 ). Furthermore, the beam 110 and the connecting hole 111 have a circumferential length in the range of 2:1 to 1:2, preferably 1:1, and are substantially the same in this embodiment (especially referring to Figure 3 ).

[0044] Thus, by forming the beam 110 connecting the annular extension 11f of the base 11a of the retainer 11 and the annular retaining portion 11c in the annular space S on the inner diameter side of the annular connecting portion 11b, the structural strength of the annular connecting portion 11b can be improved, and the displacement of the annular retaining portion 11c caused by the bending action of the annular connecting portion 11b can be restricted. When the mechanical seal 1 is used, the influence of the pressure of the sealed fluid on the fitting force of the annular retaining portion 11c is suppressed, and the sliding surface 10a of the stationary seal ring 10 is not deformed, and the retainer 11 can be prevented from being damaged. In addition, the plate thickness of the annular connecting portion 11b does not increase, and the displacement of the annular retaining portion 11c can be restricted by the beam 110, thereby making it easy to appropriately maintain the fitting force of the annular retaining portion 11c to the outer peripheral surface 10c of the stationary seal ring 10, and preventing cracks in the stationary seal ring 10 and deformation of the sliding surface 10a.

[0045] Furthermore, by providing the beams 110 at equal intervals in the circumferential direction, the structural strength of the annular connecting portion 11 b is substantially uniformly increased in the circumferential direction, thereby making it possible to reliably restrict the displacement of the annular holding portion 11 c.

[0046] In addition, the annular space S formed on the inner periphery of the retaining ring 11 is separated radially inside and outside into a first annular space S1 and a second annular space S2 by the beam 110. The annular connecting portion 11b located on the outer diameter side of the first annular space S1 separated toward the outer diameter side by the beam 110 is easy to deform, especially during shrinkage fitting. It is possible to appropriately maintain the fitting force of the annular retaining portion 11c due to the bending action of the annular connecting portion 11b while limiting the displacement of the annular retaining portion 11c by the beam 110. Therefore, when the mechanical seal 1 is in use, it is possible to appropriately maintain the fitting force of the annular retaining portion 11c against the pressure of the sealed fluid and suppress the deformation of the sliding surface 10a of the stationary sealing ring 10.

[0047] In addition, the beam 110 is integrally formed with the base 11a, the annular connecting portion 11b and the annular retaining portion 11c by the same material, so that the thermal expansion and contraction of the beam 110 during shrinkage fitting can be consistent with the thermal expansion and contraction of the retaining ring 11, so that the fitting force of the annular retaining portion 11c to the outer peripheral surface 10c of the stationary sealing ring 10 can be stabilized.

[0048] In addition, the annular retaining portion 11c extends radially inward from the annular connecting portion 11b, and further extends axially backward toward the base portion 11a, and goes around the radially inner side of the annular space S, especially the first annular space S1, so that the conical surface 11k at the front end of the annular retaining portion 11c approaches the conical surface 11h of the annular protruding portion 11f in the axial direction, thereby separating the beam 110 and the annular connecting portion 11b in the radial direction through the first annular space S1, and the first annular space S1 is axially close to the side of the annular retaining portion 11c, that is, the free end side of the annular connecting portion 11b, thereby fully exerting the bending effect of the annular connecting portion 11b. That is, the beam 110 and the free end of the annular connecting portion 11b are separated radially and axially, so that the bending effect of the annular connecting portion 11b that assists the fitting force of the annular retaining portion 11c during shrinkage fitting will not be hindered, and the influence of the pressure of the sealed fluid on the fitting force of the annular retaining portion 11c when the mechanical seal 1 is in use can be suppressed.

[0049] In addition, the axial ends of the beam 110 are connected by a virtual conical surface that extends the conical surface 11h of the annular extension portion 11f in the base 11a along the circumferential direction and a virtual conical surface that extends the conical surface 11k at the front end of the annular retaining portion 11c along the circumferential direction. Therefore, the cross-sectional area of ​​the axial ends of the beam 110 can be larger, thereby improving the strength of the beam 110.

[0050] In addition, the beam 110 is constructed in an inclined structure as described above, so that the radial component stress caused by the pressure of the sealed fluid during shrink fitting or when the mechanical seal 1 is used is partially dispersed along the axial direction, so that the fitting force of the annular retaining portion 11c is unlikely to become too large, and damage to the stationary sealing ring 10 or the retaining ring 11 can be effectively prevented.

[0051] Furthermore, since the base portion 11 a of the retainer 11 is an integral structure that also serves as a base end material for welding and fixing the corrugated tube 6 , no joint portion is formed in the retainer 11 , and the structural strength can be improved.

[0052] Furthermore, since the retainer 11 is integrally formed by a three-dimensional forming device such as a 3D printer, the first annular space S1 or the beam 110 formed inside the retainer 11 can be easily configured.

[0053] Furthermore, the retainer 11 can appropriately maintain the fitting force of the annular holding portion 11 c to the outer peripheral surface 10 c of the stationary seal ring 10 , and a highly corrosion-resistant material such as a nickel-based superalloy can be applied to the stationary seal ring 10 of the mechanical seal 1 .

[0054] As mentioned above, although the embodiment of the present invention is described based on the drawings, the specific configuration is not limited to these embodiments, and any changes or additions that do not depart from the gist of the present invention are also included in the present invention.

[0055] For example, in the above-described embodiment, the beam 110 is formed on the retaining ring 11 that holds the stationary sealing ring 10 . However, the present invention is not limited thereto, and the beam may be formed on the retaining ring 21 that holds the rotating sealing ring 20 , or on both the retaining rings 11 , 21 that hold the stationary sealing ring 10 and the rotating sealing ring 20 .

[0056] In addition, the circumferential lengths of the beam and the connecting hole are not limited to being formed to be substantially the same, and for example, they may be formed to be substantially the same as Figure 4 As shown in the modified example, the communication hole 211 is formed as a long hole longer in the circumferential direction than the beam 210. In addition, the beam is not limited to being provided in plurality, and a long C-shaped beam may be provided in the circumferential direction.

[0057] In addition, in the above-described embodiment, the beam 110 is described as extending in the axial direction by connecting a virtual conical surface obtained by extending the conical surface 11k in the front end of the annular holding portion 11c in the circumferential direction and a virtual conical surface obtained by extending the conical surface 11h of the annular extending portion 11f in the base portion 11a in the circumferential direction, but the present invention is not limited to this. For example, Figure 5 As shown in the modified example of , the beam 310 may be formed so as to connect the base portion and the inner side surface perpendicular to the axial direction of the annular holding portion. In addition, the annular extending portion 11f may not be formed in the base portion 11a.

[0058] In addition, the beam may be formed in any shape as long as it connects the base portion 11a and the annular holding portion 11c. In addition, the beam may be formed in a circular shape or a polygonal shape in a cross-sectional view.

[0059] In addition, the above embodiment describes that the annular space S formed on the inner periphery of the retainer 11 is separated radially inwardly and outwardly into the first annular space S1 and the second annular space S2 by the beam 110, and the annular connecting portion 11b is located on the outer diameter side of the first annular space S1, but the present invention is not limited thereto, and the first annular space S1 may not be formed on the outer diameter side of the beam, and the beam may be integrally formed along the inner diameter side surface of the annular connecting portion 11b. In addition, a portion of the beam, for example, a portion on the base 11a side, may be partially integrally formed on the inner diameter side surface of the annular connecting portion 11b.

[0060] Alternatively, the beam may be formed of a material different from that of the base portion 11a, the annular connecting portion 11b, and the annular holding portion 11c of the retainer 11, and both ends thereof may be fixed to the base portion 11a and the annular holding portion 11c by welding, respectively.

[0061] In addition, the annular holding portion 11 c does not need to be formed so as to go around to the radially inner side of the first annular space S1 .

[0062] In addition, if Figure 6 As shown in the modified example, the second annular space S2 may be formed between the inner periphery of the retainer 411 and the stationary seal ring 410 by the recessed portion 410 a provided on the outer periphery of the stationary seal ring 410 .

[0063] In addition, the back surface 10b of the stationary seal ring 10 does not need to abut against the inner side surface 11d of the base portion 11a of the retainer 11. In this case, by fitting the annular holding portion 11c of the retainer 11 into the annular groove formed on the outer peripheral surface 10c of the stationary seal ring 10, the axial positional displacement of the stationary seal ring 10 relative to the retainer 11 can be prevented.

[0064] In addition, the base portion of the retainer 11 and the base end material to which the bellows 6 is welded and fixed may be formed separately.

[0065] In the above-described embodiment, the stationary seal ring 10 is also urged in the axial direction by the urging force of the bellows 6 . However, the present invention is not limited thereto, and the urging force may be applied by a separately arranged spring.

[0066] Explanation of symbols

[0067] 1. Mechanical seal; 2. Rotating shaft; 3. Sleeve; 4. Housing; 5. Sealing cover; 6. Bellows; 10. Stationary sealing ring (sealing ring); 10a. Sliding surface; 11. Guard; 11a. Base; 11b. Annular connecting portion; 11c. Annular retaining portion; 11f. Annular extension portion; 11h, 11k. Conical surface; 12. Hoop; 20. Rotating sealing ring (sealing ring); 20a. Sliding surface; 21. Guard; 110. Beam; 111. Connecting hole; 210. Beam; 211. Connecting hole; 310. Beam; 410. Stationary sealing ring; 410a. Concave portion; 411. Guard; S. Annular space; S1. First annular space; S2. Second annular space.

Claims

1. A mechanical seal comprising a pair of relatively rotatable sealing rings and a retaining ring for retaining at least one sealing ring. The retainer has: an annular base; an annular retaining portion engaged with the outer periphery of the sealing ring; and an annular connecting portion axially connecting the base and the annular retaining portion, and an annular space surrounded by the base, the annular connecting portion and the annular retaining portion is formed between the outer periphery of the sealing ring and the inner periphery of the retainer. In the annular space, a beam is formed on the retaining ring to connect the base and the annular retaining portion. The annular connecting portion extends axially from the annular base portion. The annular holding portion extends radially inward from the annular connecting portion and further extends in the axial direction toward the annular base portion.

2. The mechanical seal according to claim 1, wherein: The beams are equidistant in the circumferential direction.

3. The mechanical seal according to claim 1 or 2, wherein: The beam is formed to separate the annular space into inner and outer parts in the radial direction.

4. The mechanical seal according to claim 1 or 2, wherein: The beam is integrally formed from the same material as the base.

5. The mechanical seal according to claim 1 or 2, wherein: The bellows is welded and fixed on the base.

6. The mechanical seal according to claim 1 or 2, wherein: The retaining ring is integrally formed by a three-dimensional shaping device.

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