Mechanical seal

Abstract

To provide a mechanical seal that can maintain airtightness through a secondary seal. [Solution] A space S3 is provided between the back surface 10a of the rotating sealing ring 10 and the end surface 22a of the holding portion 24, and a restricting portion 12a is provided on at least one of the rotating sealing ring 10 or the sleeve 20 to restrict the radial movement of the secondary seal 30.

Description

Technical Field

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[0001] The present invention relates to a mechanical seal, for example, a mechanical seal for 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 disposed so as to penetrate the housing. Specifically, the mechanical seal has a function of preventing leakage of a sealed fluid by bringing a sliding surface of a stationary seal ring attached to the housing side into sliding contact with a sliding surface of a rotating seal ring attached to the rotating shaft side in the circumferential direction.

[0003] For example, the mechanical seal shown in Patent Document 1 includes a seal ring that is attached to the housing in a non-rotating state and is axially movable, a mating ring that is held inside a holding portion of a sleeve externally mounted on the rotating shaft, and a gasket that seals between the mating ring and the holding portion. The holding portion has a bottomed cylindrical shape. The gasket is a cup gasket having an L-shaped cross section that extends so as to cover the back surface and the inner peripheral surface of the mating ring.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] <0000In a mechanical seal like the one described in Patent Document 1, a space is formed between the back surface of the mating ring and the bottom surface of the retaining part by a gasket, and the back surface of the mating ring and the bottom surface of the retaining part are spaced apart in the axial direction. This space allows the mating ring to follow the inclination of the seal ring, so that the sliding surfaces of the mating ring and the seal ring can maintain proper contact with each other. However, due to the centrifugal force acting on the gasket as the rotating shaft rotates, a minute radial displacement may occur between the gasket and the sleeve or rotating ring, which could prevent the gasket from maintaining its intended sealing performance.

[0006] This invention was made in view of these problems, and aims to provide a mechanical seal that can maintain airtightness through a secondary seal. [Means for solving the problem]

[0007] To solve the aforementioned problems, the mechanical seal of the present invention is: A stationary sealing ring attached to the housing side, A rotating sealing ring attached to the rotating shaft side that is inserted into the housing, A sleeve having a holding portion for holding the rotating sealing ring, It comprises an elastic secondary seal that seals the space between the rotating sealing ring and the holding portion, A mechanical seal in which the sliding surfaces of each of the sealing rings that rotate relative to each other slide against each other to separate the sealed fluid space from the leakage space, There is a space between the back surface of the rotating sealing ring and the end face of the holding portion, At least one of the rotating sealing ring or the sleeve is provided with a restricting portion that restricts the radial movement of the secondary seal. According to this, the radial movement of the secondary seal caused by centrifugal force is restricted by the restricting part, thereby suppressing radial displacement that occurs between the secondary seal and the sleeve or between the secondary seal and the rotating sealing ring, and thus maintaining the desired sealing performance by the secondary seal.

[0008] The rotating sealing ring may be provided with the restricting portion. According to this, since a restricting portion is provided on the rotating sealing ring that moves in accordance with the tilt of the stationary sealing ring, the secondary seal can easily follow the movement of the rotating sealing ring, and the radial movement of the secondary seal can be reliably restricted by the restricting portion.

[0009] The rotating sealing ring has grooves that open in the axial and radial directions, and the end faces of the grooves facing in the radial direction may constitute the restricting portion. According to this, the radially oriented end face of the groove can reliably restrict the radial movement of the secondary seal, and a large space can be secured.

[0010] The axial width of the secondary seal may be greater than the axial width of the groove. According to this, a space can be formed between the back surface of the rotating sealing ring and the end surface of the retaining part with a simple configuration.

[0011] The secondary seal may be a cup gasket. According to this, the secondary seal extends across the back surface and radial circumferential surface of the rotating sealing ring, resulting in a high level of sealing between the rotating sealing ring and the sleeve.

[0012] The secondary seal may be positioned radially offset from the sliding region between the stationary sealing ring and the rotating sealing ring. This allows for improved responsiveness of the rotating sealing ring to the stationary sealing ring. [Brief explanation of the drawing]

[0013] [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 a cross-sectional view showing a mechanical seal in Example 2 of the present invention. [Figure 4] This is a cross-sectional view showing the mechanical seal in Example 3 of the present invention. [Figure 5] It is a cross-sectional view showing the mechanical seal in Example 4 of the present invention. [Figure 6] It is a cross-sectional view showing the mechanical seal in Example 5 of the present invention. [Figure 7] It is a cross-sectional view showing the mechanical seal in Example 6 of the present invention. [Figure 8] It is a cross-sectional view showing the mechanical seal in Example 7 of the present invention.

Mode for Carrying Out the Invention

[0014] The mode for carrying out the mechanical seal according to the present invention will be described below based on examples.

Example

[0015] The mechanical seal according to Example 1 will be described with reference to FIGS. 1 and 2. Hereinafter, the left side of the paper surface of FIG. 1 will be described as the left side and the right side of the paper surface as the right side.

[0016] The mechanical seal 1 shown in FIG. 1 is for sealing between the rotating shaft 2 and the housing 3 in a fluid device. The mechanical seal 1 is an inside type that seals between the inner space S1 and the outer space S2 by the sliding surfaces 11 and 41. The inner space S1 is a leakage space communicating with the atmosphere A. The outer space S2 is a sealed fluid space into which the sealed fluid F flows. In this example, a form is exemplified in which the sealed fluid F is a high-pressure liquid and the atmosphere A is at a lower pressure than the sealed fluid F.

[0017] The mechanical seal , mainly composed of a rotating-side element 4 and a stationary-side element 5.

[0018] The stationary-side element 5 is mainly composed of a stationary seal ring 40, a seal cover 50, a biasing member 60, a bellows 70, a band 80, and a retainer 90.

[0019] The stationary sealing ring 40 is attached to the seal cover 50 in a sealed manner by tightening the bellows 70 with the band 80 and retainer 90. As a result, the stationary sealing ring 40 is provided so as to be able to move relative to the seal cover 50 fixed to the housing 3 while its rotation is restricted.

[0020] The stationary sealing ring 40 is biased axially by a biasing member 60, which is a spring. As a result, the sliding surface 41 of the stationary sealing ring 40 and the sliding surface 11 of the rotating sealing ring 10 slide in close contact with each other.

[0021] As shown in Figures 1 and 2, the rotating element 4 mainly consists of a rotating sealing ring 10, a sleeve 20, and a cup gasket 30 as a secondary seal.

[0022] The rotating sealing ring 10 is provided so as to be rotatable with the rotating shaft 2 via the sleeve 20 and the cup gasket 30.

[0023] On the right side of the rotating sealing ring 10, that is, on the back surface 10a side opposite the sliding surface 11 in the axial direction, an annular recess 12 as a groove and a plurality of recesses 13 are provided.

[0024] The annular recess 12 opens to the right and inner diameter sides. In other words, the annular recess 12 has a stepped shape formed by a circumferential surface 12a that extends axially from the back surface 10a and faces in the inner diameter direction as a restricting portion, and an end surface 12b that extends approximately perpendicularly to the inner diameter direction from the left end of the circumferential surface 12a and faces to the right (see Figure 2).

[0025] The recesses 13 open on the outer diameter side and penetrate axially. These recesses 13 are equally spaced circumferentially along the outer edge of the rotating sealing ring 10.

[0026] The sleeve 20 is made of metal and comprises an inner cylinder 21, an annular wall 22, and a plurality of projections 23. The inner cylinder 21 and the annular wall 22 constitute a retaining portion 24 that holds the rotating sealing ring 10.

[0027] The inner cylinder 21 extends axially in a cylindrical shape along the outer circumferential surface of the rotating shaft 2. The annular wall 22 extends annularly from the right end of the inner cylinder 21 toward the outer diameter.

[0028] The projection 23 extends to the left from the outer diameter end of the annular wall 22. The projection 23 is equally spaced circumferentially along the outer edge of the annular wall 22 and is inserted into the recess 13 of the rotating sealing ring 10. This restricts the circumferential relative rotation of the rotating sealing ring 10 with respect to the sleeve 20.

[0029] The cup gasket 30 is made of rubber and comprises an axial portion 31 extending in the axial direction and a radial portion 32 extending outward from the right end of the axial portion 31, forming a roughly L-shaped cross-section. The cup gasket 30 is not limited to rubber; it may be appropriately changed to any material that is more elastically deformable than the rotating sealing ring 10 or sleeve 20, such as an elastomer.

[0030] The axial portion 31 is positioned between the inner cylinder 21 of the sleeve 20 and the inner circumferential surface of the rotating sealing ring 10. The radial portion 32 is positioned between the annular wall 22 of the sleeve 20 and the back surface 10a of the rotating sealing ring 10. More specifically, the radial portion 32 is mostly positioned within the annular recess 12 in the axial direction and is sandwiched axially between the end face 12b and the end face 22a of the annular wall 22 of the sleeve 20.

[0031] The axial width D1 of the radial portion 32 is greater than the axial width D2 of the annular recess 12 (D1 > D2). Therefore, when the rotating sealing ring 10 is attached to the holding portion 24, the back surface 10a of the rotating sealing ring 10 and the end surface 22a of the annular wall 22 of the sleeve 20 are spaced apart in the axial direction. In other words, a space S3 is formed between the back surface 10a of the rotating sealing ring 10 and the end surface 22a of the annular wall 22 of the sleeve 20 (see Figure 2).

[0032] According to this, even if the stationary sealing ring 40 is tilted radially, the rotating sealing ring 10 can follow the tilt of the stationary sealing ring 40 by utilizing the space S3, thereby maintaining a state in which the sliding surface 41 of the stationary sealing ring 40 and the sliding surface 11 of the rotating sealing ring 10 are in proper contact.

[0033] Furthermore, the radial portion 32 and the annular recess 12 of the rotating sealing ring 10 are located on the inner diameter side of the sliding region R in which the sliding surfaces 11 and 41 actually slide. In other words, the radial portion 32 does not overlap with the sliding region R in the axial direction.

[0034] Next, we will explain the rotation of axis 2.

[0035] As shown in Figure 2, when the rotating shaft 2 rotates, especially at high speeds, centrifugal force acts on the cup gasket 30, applying a force that deforms the radial portion 32 by stretching it radially.

[0036] In the mechanical seal 1 of this embodiment, the circumferential surface 12a of the annular recess 12 is located on the outer diameter side of the radial portion 32, and the movement of the radial portion 32 in the outer diameter direction caused by centrifugal force is restricted by the circumferential surface 12a.

[0037] As a result, the radial portion 32 extends radially, which suppresses the formation of radial misalignment between the radial portion 32 and the back surface 10a of the rotating sealing ring 10, or between the radial portion 32 and the end face 22a of the annular wall 22 of the sleeve 20. In other words, it prevents the formation of minute gaps in the axial direction between the radial portion 32 and the end face 12b or between the radial portion 32 and the end face 22a, thus maintaining the desired sealing performance of the cup gasket 30.

[0038] Furthermore, since the circumferential surface 12a of the annular recess 12 is provided on the rotating sealing ring 10 which moves in accordance with the inclination of the stationary sealing ring 40, the radial portion 32 of the cup gasket 30 can easily follow the movement of the rotating sealing ring 10, and the circumferential surface 12a of the annular recess 12 can reliably restrict the movement of the radial portion 32 in the outer diameter direction.

[0039] Furthermore, since the axial width D1 of the radial portion 32 is greater than the axial width D2 of the annular recess 12, the difference D3 between the axial width D1 of the radial portion 32 and the axial width D2 of the annular recess 12 allows a space S3 to be formed between the back surface 10a of the rotating sealing ring 10 and the end surface 22a of the annular wall 22 of the sleeve 20. In other words, a space S3 can be formed with a simple configuration.

[0040] Furthermore, the cup gasket 30 has an axial portion 31 sandwiched between the inner cylinder 21 of the sleeve 20 and the inner circumferential surface of the rotating sealing ring 10, and a radial portion 32 sandwiched between the end face 12b of the annular recess 12 and the end face 22a of the annular wall 22 of the sleeve 20, thus providing a high level of sealing between the rotating sealing ring 10 and the sleeve 20.

[0041] Furthermore, the radial portion 32 is positioned offset inward from the sliding region R, allowing the area outside the radial portion 32 to be used as a larger space S3. As a result, the outer diameter side of the rotating sealing ring 10 can be tilted significantly with the radial portion 32 as the pivot point, thereby improving the responsiveness of the rotating sealing ring 10 to the stationary sealing ring 40.

[0042] Furthermore, the radial width D4 of the gap formed between the projection 23 of the sleeve 20 and the bottom surface 13a of the recess 13 of the rotating sealing ring 10 in the properly assembled state is greater than the axial width D3 of the space S3 (D3 > D4). Therefore, even if the rotating sealing ring 10 is tilted, the bottom surface 13a of the recess 13 does not interfere with the projection 23 of the sleeve 20, and the responsiveness of the rotating sealing ring 10 to the stationary sealing ring 40 can be improved.

[0043] In this embodiment, the circumferential surface 12a of the annular recess 12 formed by cutting out the rotating sealing ring 10 was described as the restricting portion. However, for example, a protruding portion that extends from the back surface of the rotating sealing ring toward the back surface may also be used as the restricting portion. In this case, the protruding portion may be formed in an annular shape, or multiple protrusions may be provided in the circumferential direction. [Examples]

[0044] Next, the mechanical seal according to Example 2 will be described with reference to Figure 3. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0045] As shown in Figure 3, in this embodiment 2, the mechanical seal 201 restricts the relative rotation between the rotating sealing ring 210 and the sleeve 220 by fitting a fitting portion (not shown) provided on the inner circumference of the rotating sealing ring 210 and a fitted portion (not shown) provided on the outer circumference of the inner cylinder 221 of the sleeve 220. Therefore, the sleeve 220 does not have the projection 23 of embodiment 1, and the sleeve 220 can be made smaller.

[0046] The secondary seal in this embodiment 2 is an O-ring 230. The O-ring 230 is positioned within the annular recess 212 of the rotating sealing ring 210. More specifically, the O-ring 230 is sandwiched radially between the circumferential surface 212a of the annular recess 212 of the rotating sealing ring 210 and the circumferential surface of the inner cylinder 221 of the sleeve 220, and is also sandwiched axially between the end face 212b of the annular recess 212 of the rotating sealing ring 210 and the end face 222a of the annular wall 222 of the sleeve 220.

[0047] Since the cross-sectional diameter D5 of the O-ring 230 is larger than the axial width D2' of the annular recess 212, a space S23 is formed between the back surface 210a of the rotating sealing ring 210 and the end surface 222a of the annular wall 222 of the sleeve 220.

[0048] Even when centrifugal force acts on the O-ring 230 during rotation of the rotating shaft 2, its movement toward the outer diameter is restricted by the circumferential surface 212a of the annular recess 212 located on the outer diameter side, thus maintaining the desired sealing performance of the O-ring 230.

[0049] Furthermore, since the annular wall 222 of the sleeve 220 has a smaller radial dimension than the rotating sealing ring 210, the rotating sealing ring 210 can move more significantly in response to the tilt of the stationary sealing ring 40. [Examples]

[0050] Next, the mechanical seal according to Example 3 will be described with reference to Figure 4. Note that the description of components that are identical to those in Example 2 and therefore redundant will be omitted.

[0051] As shown in Figure 4, the mechanical seal 301 of this embodiment 3 has a secondary seal consisting of two O-rings 330 and 331.

[0052] One of the O-rings, the O-ring 330, is sandwiched radially between the inner surface of the rotating sealing ring 310 and the outer surface of the inner cylinder 321 of the sleeve 320. The outer diameter portion of the O-ring 330 is positioned within an annular groove 314 provided on the inner surface of the rotating sealing ring 310, and the inner diameter portion is positioned within an annular groove 325 provided on the outer surface of the inner cylinder 321. This restricts the axial movement of the O-ring 330.

[0053] The other O-ring 331 is sandwiched axially between the end face 312b of the annular recess 312 of the rotating sealing ring 310 and the end face 322a of the annular wall 322 of the sleeve 320.

[0054] Although the annular grooves 314 and 325 are shown as having a roughly triangular shape in cross-section, they are not limited to this and can be freely changed to a rectangular shape in cross-section, etc. [Examples]

[0055] Next, the mechanical seal according to Example 4 will be described with reference to Figure 5. Note that the description of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0056] As shown in Figure 5, the mechanical seal 401 of this embodiment 4 has an annular projection 414 that protrudes inward from the inner circumferential surface of the rotating sealing ring 410.

[0057] This annular projection 414 is positioned to the left of the axial portion 431 of the cup gasket 430 when the cup gasket 430 and the rotating sealing ring 410 are attached to the holding portion 424 of the sleeve 420, and presses the axial portion 431 to the right. Therefore, when the cup gasket 430 and the rotating sealing ring 410 are attached, the axial portion 431 and the rotating sealing ring 410 are less likely to move relative to each other in the axial direction, making it less likely for the cup gasket 430 to be poorly attached.

[0058] In this embodiment 4, the annular projection 414 was formed in an annular shape, but multiple projections may be provided in the circumferential direction. [Examples]

[0059] Next, the mechanical seal according to Example 5 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.

[0060] As shown in Figure 6, the rotating sealing ring 510 of the mechanical seal 501 in this embodiment 5 does not have an annular recess, and the back surface 510a is a flat surface.

[0061] The sleeve 520 has an annular recess 525 formed on the inner diameter side of the end face 522a of the annular wall 522. The annular recess 525 consists of a circumferential surface 525a that extends to the right from the inner diameter side of the end face 522a as a restricting portion, and an end face 525b that extends inward from the right end of the circumferential surface 525a and connects to the outer circumferential surface of the inner cylinder 521.

[0062] The radial portion 532 of the cup gasket 530 is positioned in the annular recess 525. The axial width D6 of the radial portion 532 is greater than the axial width D7 of the annular recess 525 (D6 > D7). As a result, a space S3' is formed between the end face 522a of the annular wall 522 and the back surface 510a of the rotating sealing ring 510.

[0063] When the rotating shaft 2 rotates, even if centrifugal force acts on the radial portion 532, the circumferential surface 525a of the annular recess 525 located on the outer diameter side of the radial portion 532 restricts the radial movement of the radial portion 532. This ensures that the desired sealing performance by the cup gasket 530 can be maintained.

[0064] In this embodiment 5, the circumferential surface 525a of the annular recess 525 formed by cutting out the sleeve 520 was described as the restricting portion, but the convex portion that protrudes to the left from the annular wall of the sleeve may also be used as the restricting portion.

[0065] Furthermore, the regulating portion is not limited to being formed in a continuous ring shape, but may also be provided in multiple locations in the circumferential direction, for example. [Examples]

[0066] Next, the mechanical seal according to Example 6 will be described with reference to Figure 7. Note that the description of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0067] As shown in Figure 7, the rotating sealing ring 610 of the mechanical seal 601 in this embodiment 6 does not have an annular recess. The back surface 610a of the rotating sealing ring 610 is a rough surface with fine irregularities formed over its entire surface.

[0068] In the installed state of the rotating sealing ring 610, the irregularities on the back surface 510a of the rotating sealing ring 510 bite into the radial portion 632 of the cup gasket 630. As a result, the frictional force between the back surface 610a of the rotating sealing ring 610 and the radial portion 632 of the cup gasket 630 is increased. Therefore, even if centrifugal force acts on the radial portion 632, its radial movement is restricted, and the desired sealing performance by the cup gasket 630 can be maintained.

[0069] In other words, in this embodiment 6, the back surface 610a of the rotating sealing ring 610 functions as a restricting portion.

[0070] In this embodiment 6, the example shows that the back surface 610a of the rotating sealing ring 610 is a rough surface. However, for example, the back surface of the rotating sealing ring may be processed to increase the coefficient of friction, or a high-friction member may be fixed to the back surface of the rotating sealing ring. [Examples]

[0071] Next, the mechanical seal according to Example 7 will be described with reference to Figure 8. Note that the description of components that are identical to those in Example 6 and therefore redundant will be omitted.

[0072] As shown in Figure 8, in this embodiment 1, the mechanical seal 701 has a rough surface on the end face 722a of the annular wall 722 of the sleeve 720, with fine irregularities formed over its entire surface.

[0073] In the installed state of the rotating sealing ring 710, the irregularities of the end face 722a of the annular wall 722 bite into the radial portion 732 of the cup gasket 730. As a result, the frictional force between the end face 722a of the annular wall 722 of the sleeve 720 and the radial portion 732 of the cup gasket 730 is increased. Therefore, even if centrifugal force acts on the radial portion 732, the radial movement of the radial portion 732 is restricted, and the desired sealing performance by the cup gasket 730 can be maintained.

[0074] In other words, in this embodiment 7, the end face 722a of the annular wall 722 functions as a restricting portion.

[0075] In this embodiment 7, the end face 722a of the annular wall 722 is shown as a rough surface, but for example, the back surface of the rotating sealing ring may be processed to increase the coefficient of friction, or a high-friction member may be fixed to the back surface of the rotating sealing ring.

[0076] 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.

[0077] For example, in the above embodiments 1 to 7, an inside-type mechanical seal was described in which the inner space S1 is connected to the atmosphere A and the fluid to be sealed F flows into the outer space S2. However, it may also be applied to an outside-type mechanical seal in which the fluid to be sealed F flows into the inner space S1 and the outer space S2 is connected to the atmosphere A.

[0078] Furthermore, although the sealed fluid was described as a high-pressure liquid in Examples 1 to 7, it is not limited to this and may be a gas or a low-pressure liquid, or a mist-like mixture of liquid and gas.

[0079] Furthermore, although the fluid on the leakage space side was described as air, which is a low-pressure gas, in Examples 1 to 7 above, it is not limited to this and may be a liquid or a high-pressure gas, or it may be a mist-like mixture of liquid and gas.

[0080] Furthermore, in Examples 1 to 7, the sealed fluid space side has been described as the high-pressure side and the leak space side as the low-pressure side. However, the sealed fluid space side may be the low-pressure side and the leak space side may be the high-pressure side, or the sealed fluid space side and the leak space side may be at approximately the same pressure.

[0081] Furthermore, while embodiments 1 to 7 above illustrate a configuration in which the back surface of the rotating sealing ring is substantially flat, it is sufficient that an axial space is formed between the backmost surface of the rotating sealing ring and the end face of the retaining portion, and the back surface of the rotating sealing ring may have an uneven or curved shape. For example, the back surface of the rotating sealing ring may have a shape in which radially extending recesses and protrusions are alternately arranged in the circumferential direction.

[0082] Furthermore, while embodiments 6 and 7 illustrate a configuration in which either the back surface of the rotating sealing ring or the end surface of the sleeve is a rough surface, both the back surface of the rotating sealing ring and the end surface of the sleeve may be rough surfaces.

[0083] Furthermore, while embodiments 1 to 7 illustrate a configuration in which the secondary seal is positioned on the inner diameter side of the relationship between the rotating sealing ring and the sleeve holding portion, the secondary seal may also be positioned on the outer diameter side of the relationship between the rotating sealing ring and the sleeve holding portion. In this case as well, the regulating portion can restrict the movement of the secondary seal toward the outer diameter side due to centrifugal force, thereby enabling the secondary seal to exhibit its desired sealing performance.

[0084] Furthermore, while embodiments 1 to 7 above illustrate a configuration in which the biasing member is located on the fixed side and biases the stationary sealing ring, the biasing member may also be positioned on the rotating shaft side to bias the rotating sealing ring. For example, the biasing member may be positioned between the rotating shaft and the sleeve, and the rotating sealing ring may be biased via the sleeve. [Explanation of symbols]

[0085] 1 Mechanical seal 2 rotation axes 3 Housing 10 Rotating Sealing Rings 10a back 11 Sliding surface 12. Annular recess (groove) 12a Surrounding surface (regulating part) 12b End face 20 sleeves 22 Ring Wall 22a End face 24 Holding part 30 Cup Gaskets (Secondary Seals) 31 Axial location 32 Radial portion 40 Stationary sealing ring 41 Sliding surface 60 biasing member D1 Axial width D2 Axial width R sliding area S1 inner space S2 outside space

Claims

1. A stationary sealing ring attached to the housing side, A rotating sealing ring attached to the rotating shaft side that is inserted into the housing, A sleeve having a holding portion for holding the rotating sealing ring, It comprises an elastic secondary seal that seals the space between the rotating sealing ring and the holding portion, A mechanical seal in which the sliding surfaces of each of the sealing rings that rotate relative to each other slide against each other to separate the sealed fluid space from the leakage space, There is a space between the back surface of the rotating sealing ring and the end face of the holding portion, A mechanical seal in which at least one of the rotating sealing ring or the sleeve is provided with a restricting portion that restricts the radial movement of the secondary seal.

2. The mechanical seal according to claim 1, wherein the regulating portion is provided on the rotating sealing ring.

3. The mechanical seal according to claim 2, wherein the rotating sealing ring has grooves that open in the axial direction and radially, and the radially facing end faces of the grooves constitute the restricting portion.

4. The mechanical seal according to claim 3, wherein the axial width of the secondary seal is greater than the axial width of the groove.

5. The mechanical seal according to claim 1, wherein the secondary seal is a cup gasket.

6. The mechanical seal according to any one of claims 1 to 5, wherein the secondary seal is positioned radially offset from the sliding region between the stationary sealing ring and the rotating sealing ring.

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