Mechanical seal

Abstract

To provide a mechanical seal for allowing easier grasp of a wearing situation.SOLUTION: A mechanical seal 1 includes a pair of seal elements Q1, R1 to be relatively rotated, one seal element R1 having a seal member 6 which is adapted to be energized by energizing means 9 and movable in the axial direction relative to a fixed member 7 fixing the seal member 6, and further includes a visual confirmation component 10 fixed to the fixed member 7 and having viewing windows 14, 15 for allowing visual confirmation of a visually confirmed object 6d as part of one seal element R1 from the lateral side.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a mechanical seal, for example, a mechanical seal capable of determining the wear state of a seal member. [Background technology]

[0002] Mechanical seals are used by being installed between a housing of a fluid equipment and a rotating shaft arranged to pass through the housing. More specifically, mechanical seals have the function of preventing leakage of the sealed fluid by bringing the sliding surface of a stationary seal ring attached to the housing side into sliding contact with the sliding surface of a rotating seal ring attached to the rotating shaft side, which rotates, in the circumferential direction using the biasing force of a biasing means.

[0003] In such mechanical seals, the sliding surfaces of the stationary seal ring and the rotating seal ring may wear due to relative sliding between them. When the sliding surfaces wear, leakage of the sealed fluid and an increase in the frictional force generated during relative sliding may occur. Therefore, leakage during operation and dimensional measurement of the spring gap during stoppage are visually checked, and spare parts are prepared and the replacement time is determined according to the wear state of the sliding surfaces. There is also known a mechanical seal such as that disclosed in Patent Document 1, which allows the wear state to be judged from the appearance without disassembling the mechanical seal.

[0004] In the mechanical seal of Patent Document 1, a floating seat, which is biased toward a seal ring by a coil spring, is movable in the axial direction relative to a case that fixes the floating seat. The floating seat is prevented from rotating by a drive pin that is inserted into the case. The drive pin is inserted into an engagement hole that penetrates the case so as to be movable in the axial direction. The wear amount measuring end of the drive pin protrudes outward from the end face of the case.

[0005] In the mechanical seal of Patent Document 1, when at least one of the seal ring and the floating seat wears, the floating seat is pushed by the coil spring by the amount of wear and moves toward the seal ring, thereby maintaining contact between the seal ring and the floating seat. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Microfilm of Utility Model Application No. 59-53556 (Utility Model Application No. 60-167265) (pages 6-9, Figure 3) Summary of the Invention [Problem to be solved by the invention]

[0007] In the mechanical seal of Patent Document 1, when the floating seat moves toward the seal ring, the drive pin also moves with the floating seat, and the portion of the wear measurement end of the drive pin that protrudes outward from the end face of the case becomes shorter. This makes it possible to determine the wear condition by visually checking the wear measurement end of the drive pin.

[0008] An object of the present invention is to provide a mechanical seal that allows the wear state to be more easily grasped. [Means for solving the problem]

[0009] In order to solve the above problems, the mechanical seal of the present invention comprises: A pair of sealing elements that rotate relative to one another; One of the seal elements is a mechanical seal in which a seal member biased by a biasing means is movable in an axial direction relative to a fixed member that fixes the seal member, A visual component is provided which is fixed to the fixed member and has a sight window through which a visual object which is a part of the one of the seal elements can be viewed from the side. According to this, the amount of wear of the seal member can be easily grasped by changing the position of the visual object, which is part of one of the seal elements visually observed through the sight hole in the visual component.

[0010] The visual component may have a piece extending from the fixed member side along a side of the member having the visual target, and the sight hole may be formed on the piece. This allows the sight glass to be positioned accurately relative to the object being viewed.

[0011] The visual component may be fixed to the fixing member so that its position can be adjusted in the axial direction. This allows for compatibility with a variety of one-side seal elements.

[0012] The visually inspected object may be an edge of a member constituting the one seal element. This allows wear to be detected easily and accurately.

[0013] The sight glass may have a shape having a different width in the axial direction. This makes it easier to detect wear.

[0014] The sight glass may be circular in shape. This allows for easy recognition since the visual recognition area changes gradually.

[0015] The sight glass may be at least one of a hole and a notch. This allows the sight glass to be constructed simply and easily.

[0016] The hole and the notch may be provided at different positions in the axial direction. This makes it easy to easily detect the degree of wear.

[0017] The sight glass may be provided in a plurality of locations in the circumferential direction. This allows wear to be detected reliably. [Brief description of the drawings]

[0018] [Figure 1] 1 is a cross-sectional view showing a mechanical seal according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a view of the visual inspection part of the first embodiment as viewed from a radial direction. [Diagram 3] (a) is a view of the piece and visual target of Example 1 from the radial direction, (b) is a view of the piece and visual target from the radial direction in a state where the wear is more advanced than in (a), and (c) is a view of the piece and visual target from the radial direction in a state where the wear is more advanced than in (b). [Figure 4] 1A is a view of a first variation of the sight glass seen from a radial direction, FIG. 1B is a view of a second variation of the sight glass seen from a radial direction, and FIG. 1C is a view of a third variation of the sight glass seen from a radial direction. [Diagram 5] FIG. 11 is a cross-sectional view showing a visual component according to a second embodiment of the present invention. [Figure 6] FIG. 11 is a cross-sectional view showing a mechanical seal according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mechanical seal according to the present invention will be described below with reference to the following examples. EXAMPLES

[0020] A mechanical seal according to a first embodiment will be described with reference to Fig. 1 to Fig. 4. In the following description, the left and right sides as viewed from the front side of Fig. 1 are the left and right sides of the mechanical seal.

[0021] As shown in FIG. 1, a mechanical seal 1 of this embodiment is provided between a housing 2 and a rotating shaft 3 in a rotary machine to prevent leakage of a sealed fluid in the vicinity.

[0022] The mechanical seal 1 is mainly composed of a stationary element Q1 as a seal element fixed to a housing 2, and a rotating element R1 as a seal element fixed to a rotating shaft 3.

[0023] The stationary element Q1 includes a case 4 and a stationary seal ring 5.

[0024] The stationary seal ring 5 is made of ceramic and formed in an annular shape, and its left end surface is a sliding surface 5a.

[0025] The stationary seal ring 5 is disposed between the case 4 fixed to the housing 2 in a non-rotating state and in a state where its movement in the axial direction is restricted. In addition, the space between the stationary seal ring 5 and the housing 2, and the space between the stationary seal ring 5 and the case 4 are sealed by packing.

[0026] The rotating element R1 is mainly composed of a rotating seal ring 6 as a seal member, a collar 7 as a fixed member, a compression ring 8, a coil spring 9 as a biasing means, and a visual component 10.

[0027] The rotary seal ring 6 is made of filler-containing PTFE (Polytetrafluoroethylene) and is formed in an annular shape. The rotary seal ring 6 has an annular protrusion protruding from the right end in the axial direction. The right end surface of the annular protrusion is a sliding surface 6a.

[0028] The rotary seal ring 6 is fitted onto the rotary shaft 3. The radial gap between the rotary shaft 3 and the rotary seal ring 6 is sealed by a packing.

[0029] The stationary seal ring 5 and the rotating seal ring 6 are not limited to those made of a combination of hard and soft materials. Also, materials other than those mentioned above can be used for the sliding members as long as they are used as sliding materials for mechanical seals, and examples of materials that can be used include ceramics, metal materials, resin materials, composite materials, and the like.

[0030] The collar 7 is formed in a cylindrical shape. The collar 7 has a cylindrical extension 7a extending axially rightward. The collar 7 is fitted onto the rotating shaft 3. The collar 7 is fixed to the rotating shaft 3 by a set screw 70 that penetrates the collar 7 in the radial direction and is pressed against the rotating shaft 3.

[0031] The compression ring 8 is formed in an annular shape. The compression ring 8 is fitted onto the extension portion 7a of the collar 7.

[0032] The compression ring 8 also has a female screw hole formed from the axial left end surface toward the axial right side. A male screw portion of a drive pin 71 inserted into a stepped through hole 7b that axially penetrates the collar 7 is screwed into this female screw hole. This allows the compression ring 8 to move axially relative to the collar 7, while being connected to the collar 7 so as to be rotatable together with the collar 7. The number and arrangement of the drive pins 71 may be changed as appropriate.

[0033] A coil spring 9 is disposed in a compressed state between the collar 7 and the compression ring 8 in the axial direction. The number and arrangement of the coil springs 9 may be changed as appropriate.

[0034] The compression ring 8 is pressed against the rotary seal ring 6 by the biasing force of the coil spring 9. In other words, the rotary seal ring 6 receives the biasing force of the coil spring 9 via the compression ring 8. As a result, the sliding surface 6a of the rotary seal ring 6 is pressed against the sliding surface 5a of the stationary seal ring 5.

[0035] Furthermore, the collar 7 is formed with a through hole 7c that penetrates in the axial direction at a position that is out of phase with the stepped through hole 7b in the circumferential direction. The compression ring 8 is formed with a through hole 8a that penetrates in the axial direction. The rotary seal ring 6 is formed with a notched recess 6b that extends axially rightward from its left end face and is open to the axial left side and to the outer diameter side.

[0036] A knock pin 72 is press-fitted and fixed in the through hole 7c of the collar 7. The knock pin 72 may be welded or bonded to the collar 7, and the fixing method may be changed as appropriate.

[0037] Furthermore, the knock pin 72 passes through the through hole 8a in the compression ring 8, and its right axial end is inserted into the notched recess 6b in the rotary seal ring 6. The knock pin 72 is disposed so as to be movable axially relative to the through hole 8a and the notched recess 6b. Furthermore, the knock pin 72 is engageable with the notched recess 6b in the circumferential direction. As a result, the rotary seal ring 6 is coupled to the collar 7, which rotates integrally with the rotary shaft 3, while being permitted to move axially relative to the collar 7.

[0038] The rotating seal ring 6 is capable of rotating relative to the stationary seal ring 5 with its sliding surface 6a pressed against the sliding surface 5a of the stationary seal ring 5 by the biasing force of the coil spring 9. In this way, the mechanical seal 1 seals between the space on the outer diameter side of the sliding surfaces 5a, 6a and the space on the inner diameter side.

[0039] The visual inspection part 10 is a piece-shaped member whose circumferential cross section is formed into an upside-down L-shape. The visual inspection part 10 has a base 11 extending in the radial direction of the rotating shaft 3, and a piece 12 extending from the outer diameter end of the base 11 to the right in the axial direction of the rotating shaft 3.

[0040] The visual component 10 will be described based on the radial, axial, and circumferential directions of the rotating shaft 3. In the following description, however, only the terms "radial," "axial," and "circumferential" will be used, and the preface "of the rotating shaft 3" will be omitted.

[0041] The base 11 is a plate-like member extending in the radial direction. A female screw hole 11a is formed in the base 11 so as to penetrate in the axial direction. The collar 7 is formed with a female screw hole 7d extending from its left end face toward the right in the axial direction.

[0042] The base 11 is fixed to the collar 7 by having the male thread portion 13a of the bolt 13 screwed into the female thread hole 11a of the base 11, which is further screwed into the female thread hole 7d of the collar 7. The right axial end face of the base 11 fixed to the collar 7 is pressed against the left axial end face of the collar 7.

[0043] The piece 12 is cantilevered on the base 11 and extends to the right in the axial direction. The piece 12 extends approximately parallel to the axis of the rotating shaft 3 and the outer peripheral surface 6c of the rotating seal ring 6. In addition, the piece 12 is located on the outer diameter side of the base 11 when viewed from the axial direction, and is arc-shaped.

[0044] On the inner diameter side of the piece 12, there are formed, in order from the left, an inner diameter side inner circumferential surface 12a, an inclined surface 12b, and an outer diameter side inner circumferential surface 12c.

[0045] The inner diameter side inner peripheral surface 12a extends axially to the right, substantially perpendicular to the axial right end face of the base portion 11. The inner diameter side inner peripheral surface 12a is curved in the circumferential direction so as to fit along the outer circumferential surface of the collar .

[0046] With the base 11 fixed to the collar 7, the inner peripheral surface 12a on the inner diameter side abuts against the outer peripheral surface of the collar 7. In other words, the collar 7 supports the left end of the piece 12 in the radial direction. This makes it difficult for the axial tip of the piece 12 to tilt toward the inner diameter side.

[0047] The inclined surface 12b extends axially rightward from the right end of the inner diameter side inner circumferential surface 12a, inclining toward the outer diameter side.

[0048] The outer diameter side inner peripheral surface 12c extends axially rightward from the axial right end of the inclined surface 12b. The outer diameter side inner peripheral surface 12c extends generally parallel to the outer peripheral surface 6c of the rotary seal ring 6. With the base 11 fixed to the collar 7, the outer diameter side inner peripheral surface 12c is located at a position spaced outward from the collar 7, the compression ring 8, and the rotary seal ring 6. This prevents the piece 12 from contacting the compression ring 8 or the rotary seal ring 6.

[0049] As shown in FIG. 2, the piece 12 is formed with a hole 14 as an observation window and a notch 15 as an observation window.

[0050] Hole 14 has a circular shape when viewed from the radial direction, and radially penetrates the right axial end of piece 12. In order to make it easy to view a visual target, which will be described later, it is preferable that hole 14 has a diameter of 0.5 mm or more.

[0051] The notch 15 has a rectangular shape when viewed in the radial direction, and penetrates the piece 12 in the radial direction. The notch 15 is open toward the right side in the axial direction, that is, toward the rotary seal ring 6 side.

[0052] Furthermore, the notch 15 is rectangular in shape with a circumferential dimension longer than the axial dimension. In addition, the circumferential dimension of the notch 15 is substantially constant throughout the axial direction. Note that, in order to facilitate visual recognition of a visual recognition target, which will be described later, the circumferential dimension, i.e., the width, of the notch 15 is preferably 0.5 mm or more.

[0053] Further, notch 15 is formed at a position that is out of phase with respect to the circumferential direction and at a position that is out of phase with respect to the axial direction from hole 14. More specifically, notch 15 is formed axially closer to the rotary seal ring 6 than hole 14, i.e., on the right side in the axial direction.

[0054] Next, a method for checking the wear state of the stationary seal ring 5 and the rotating seal ring 6 using the visual inspection part 10 will be described with reference to Fig. 3. In Fig. 3, the rotating seal ring 6 is given a dot pattern to clearly show the rotating seal ring 6.

[0055] First, the state immediately after the mechanical seal 1 is assembled to the rotary machine will be described. With reference to Fig. 3(a), the edge 6d of the rotary seal ring 6 can be seen through the hole 14 viewed from the radial direction. In other words, the hole 14 is positioned in the axial direction so that no wear occurs or the wear is within an acceptable range in the range where the edge 6d is visible through the hole 14. The edge 6d is the object to be visually confirmed in this embodiment, and is the portion where the outer peripheral surface 6c of the rotary seal ring 6 and the left axial end face of the rotary seal ring 6 intersect.

[0056] In order to make the edge 6d of the rotating seal ring 6 more clearly visible, the rotating seal ring 6 and the compression ring 8 may be colored to different colors, or paint may be applied to a portion of the outer circumferential surface 6c continuous with the edge 6d.

[0057] Furthermore, the visual inspection object may be changed as appropriate, for example, by attaching a marker to an area necessary for identifying the wear state, or by interposing a thin-plate-shaped visual inspection object member between the rotating seal ring 6 and the compression ring 8. In other words, it may be possible to make the determination using a visual inspection object other than the edge, or a visual inspection object other than the edge may be used in combination with the edge.

[0058] The stationary seal ring 5 and the rotating seal ring 6 may be worn down due to the relative sliding of the sliding surface 5a of the stationary seal ring 5 and the sliding surface 6a of the rotating seal ring 6. In other words, the axial dimension of the stationary seal ring 5 and the rotating seal ring 6 becomes shorter by the amount of wear.

[0059] Even in such a case, the rotating seal ring 6 is pressed toward the stationary seal ring 5 by the biasing force of the coil spring 9, so that the sliding surface 6a of the rotating seal ring 6 is kept in pressure contact with the sliding surface 5a of the stationary seal ring 5.

[0060] In other words, the rotary seal ring 6 and the compression ring 8 move axially to the right as at least one of the stationary seal ring 5 and the rotary seal ring 6 wears. That is, the edge 6d of the rotary seal ring 6 moves axially to the right, i.e., toward the stationary seal ring 5, as the wear of the stationary seal ring 5 or the rotary seal ring 6 progresses.

[0061] Because the hole 14 is circular, its circumferential width decreases toward the right in the axial direction. As a result, the area in which the rotary seal ring 6 can be seen through the hole 14 decreases rapidly as the wear of the stationary seal ring 5 and the rotary seal ring 6 progresses. This makes it easier to grasp the wear status of the stationary seal ring 5 and the rotary seal ring 6.

[0062] Furthermore, in a situation where the area in which the rotating seal ring 6 can be seen through the hole 14 has simply decreased, there may be other reasons besides wear of the stationary seal ring 5 and the rotating seal ring 6. Possibilities other than wear include the rotating seal ring 6 having moved toward the collar 7 due to some kind of use, or the edge 6d becoming difficult to see due to the adhesion of dirt or the like.

[0063] The visual inspection part 10 in this embodiment has a one-sided shape. In other words, the position of the edge 6d can be grasped by directly visually inspecting the rotary seal ring 6 on both circumferential outer sides of the visual inspection part 10. This makes it possible to accurately determine whether the stationary seal ring 5 or the rotary seal ring 6 has worn down. This also applies when the stationary seal ring 5 or the rotary seal ring 6 has worn down, as described later.

[0064] 3(b), when wear of the stationary seal ring 5 or the rotary seal ring 6 progresses and the edge 6d of the rotary seal ring 6 cannot be seen through the hole 14, it can be determined that it is time to order a spare stationary seal ring 5 or a spare rotary seal ring 6. In other words, the hole 14 is positioned in the axial direction so that when the edge 6d cannot be seen through the hole 14, it is time to order a spare stationary seal ring 5 or a spare rotary seal ring 6.

[0065] As wear of the stationary seal ring 5 and the rotating seal ring 6 progresses further from the state shown in FIG. 3(b), the edge 6d of the rotating seal ring 6 moves further axially to the right.

[0066] 3(c), when the edge 6d is visible through the notch 15 as viewed from the radial direction, it can be determined that it is time to replace the stationary seal ring 5 and the rotating seal ring 6 with their respective spare parts. In other words, the notch 15 is positioned in the axial direction so that when the edge 6d is visible through the notch 15, it is time to replace the stationary seal ring 5 and the rotating seal ring 6 with their respective spare parts.

[0067] As described above, in the mechanical seal 1 of this embodiment, the amount of wear of the stationary seal ring 5 and the rotating seal ring 6 can be easily grasped by changing the position of the edge 6d of the rotating seal ring 6, which is part of the rotating element R1, which is visible through the hole 14 and the notch 15 in the visual part 10.

[0068] The visual component 10 has a piece 12 that extends from the collar 7 side along the side of the rotary seal ring 6, i.e., along the outer circumferential surface 6c, and the piece 12 is formed with a hole 14 and a notch 15. This allows the hole 14 and the notch 15 to be positioned accurately on the edge 6d of the rotary seal ring 6.

[0069] Furthermore, since the visual component 10 has a one-sided shape, it can be easily installed even in a mechanical seal that is already installed in a rotating machine without being provided with the visual component 10, for example.

[0070] Furthermore, since the object to be visually confirmed in this embodiment is the edge 6d of the rotary seal ring 6, wear can be detected easily and accurately.

[0071] In addition, the hole 14 is circular when viewed from the radial direction, and has a shape with a different circumferential width in the axial direction, so that wear can be easily detected. Furthermore, the visible area gradually changes as wear progresses, so that the wear state can be easily recognized.

[0072] In addition, by forming hole 14 in a circular shape, it is possible to easily and reliably form a shape tapering toward the right in the axial direction. For example, holes 114, 214, and 314 in Modifications 1 to 3 described below are difficult to form only by drilling with a drilling machine, and the number of work steps required to approximately align the center of the circumferential width with the axial direction of rotating shaft 3 increases, which can be cumbersome.

[0073] Furthermore, because the notch 15 has a rectangular shape with a substantially constant circumferential width in the axial direction when viewed from the radial direction, it is possible to ensure a range in which the edge 6d of the rotary seal ring 6 can be confirmed. For example, even if the axis of the rotary seal ring 6 wears so that it tilts relative to the axis of the rotating shaft 3, the edge 6d can be easily visually confirmed.

[0074] Furthermore, since the notch 15 is rectangular, it is possible to easily recognize whether the linear edge 6d is inclined with respect to the circumferential direction of the rotating shaft 3 or not.

[0075] Moreover, the sight glass of this embodiment is the hole 14 and the notch 15, and therefore can be constructed simply.

[0076] In addition, since the hole 14 and the notch 15 are provided at different axial positions, the timing for ordering spare parts and the timing for replacing the spare parts can be recognized at different times. In other words, the degree of wear can be easily detected. This makes it easier to secure spare parts by the time they need to be replaced, so the stationary seal ring 5 and the rotating seal ring 6 can be replaced smoothly.

[0077] Furthermore, since the hole 14 and the notch 15 are provided at positions with different circumferential phases, it is easy to recognize whether the edge 6d of the rotating seal ring 6 is visible through the hole 14 or the edge 6d of the rotating seal ring 6 is visible through the notch 15.

[0078] In addition, since the plate thickness of the visual component 10 is thin at the portion of the piece 12 where the hole 14 and the notch 15 are formed, the edge 6d of the rotating seal ring 6 can be easily visually observed through the hole 14 and the notch 15.

[0079] Note that multiple visual inspection parts 10 may be provided in the circumferential direction. With this configuration, even if the rotary seal ring 6 wears so that its axis tilts relative to the axis of the rotating shaft 3, it can be reliably detected. From this perspective, when multiple visual inspection parts 10 are provided, they are preferably equally spaced.

[0080] Furthermore, if multiple visual components 10 are provided in the circumferential direction, regardless of the position at which the rotating shaft 3 stops, one of the visual components 10 is likely to stop in a position that is easy to see, making it easy to check the wear condition.

[0081] Here, first to third modified examples of the observation window will be described with reference to FIG.

[0082] Referring to FIG. 4(a) showing the first modified example of the sight glass, a piece 112 is formed with a semicircular hole 114 when viewed from the radial direction, and a semicircular notch 115 when viewed from the radial direction.

[0083] The hole 114 has a semicircular shape that protrudes axially to the right, that is, toward the rotary seal ring 6. Even with this shape, the visible area gradually changes as wear progresses, so it is easy to recognize.

[0084] The notch 115 has a semicircular shape that protrudes axially leftward, that is, toward the collar 7. Even with this shape, the visible area gradually changes as wear progresses, so it is easy to recognize.

[0085] Referring to FIG. 4(b) showing a second modified example of the sight glass, a hole 214 that is D-shaped when viewed from the radial direction and a notch 215 that is laterally inverted D-shaped when viewed from the radial direction are formed in a piece 212.

[0086] The hole 214 has a portion whose circumferential width is approximately constant along the axial direction, and a semicircular portion that protrudes to the right in the axial direction. With this shape, by providing a portion whose circumferential width is approximately constant along the axial direction, it is possible to easily recognize whether the linear edge 6d is tilted relative to the circumferential direction of the rotating shaft 3. In addition, in the semicircular portion, the visible area gradually changes as wear progresses, making it easy to recognize.

[0087] The notch 115 has a semicircular portion protruding to the left in the axial direction and a portion whose circumferential width is approximately constant along the axial direction. With this shape, the semicircular portion is easy to recognize because the visual recognition area gradually changes as wear progresses. In addition, by providing a portion whose circumferential width is approximately constant on the axial right side of the semicircular portion, i.e., on the side where wear has progressed, it is easy to recognize whether the linear edge 6d is tilted with respect to the circumferential direction of the rotating shaft 3.

[0088] Referring to FIG. 4(c) showing the third modified example of the sight glass, piece 312 is formed with triangular hole 314 when viewed from the radial direction, and triangular cutout 315 when viewed from the radial direction.

[0089] The hole 314 is triangular and protrudes to the right in the axial direction. Even with this shape, the visible area changes gradually as wear progresses, making it easy to recognize.

[0090] The notch 315 is triangular and protrudes axially to the left. Even with this shape, the visible area changes gradually as wear progresses, making it easy to recognize. EXAMPLES

[0091] Next, a visual confirmation component according to a second embodiment will be described with reference to Fig. 5. Note that a description of the same configuration as that of the first embodiment will be omitted.

[0092] As shown in FIG. 5, the visual inspection component 110 of this embodiment has a base portion 111 formed with a large inner diameter female screw hole 111a and a small inner diameter female screw hole 111b.

[0093] A male threaded portion 13a of a large diameter bolt 113 is screwed into the large inner diameter female threaded hole 111a.

[0094] The small inner diameter female screw hole 111b penetrates in the axial direction at a position that is out of phase with the large inner diameter female screw hole 111a in the radial direction. The small inner diameter female screw hole 111b has a smaller diameter than the large inner diameter female screw hole 111a. A male screw portion 116a of a small diameter bolt 116 is screwed into the small inner diameter female screw hole 111b.

[0095] The small diameter bolt 116 has its head pressed against the left end surface of the base 111, and the right axial end of the male threaded portion 116a abuts against the left axial end surface of the collar 7. This allows the base 111 to be fixed to the collar 7 at a position spaced axially to the left of the collar 7.

[0096] In other words, by adjusting the axial length of the male thread portion 116a of the small diameter bolt 116 and the dimension of the male thread portion 116a screwed into the small inner diameter female threaded hole 111b, it is possible to adjust the axial positions of the hole 14 and the notch 15 relative to the rotating seal ring 6 and the compression ring 8. The small inner diameter female threaded hole 111b and the small diameter bolt 116 are means for adjusting the position of the visual component 110.

[0097] In this way, in the visual component 110 of this embodiment, even if the sealing element has a different visual target position from that of the first embodiment, the axial positions of the holes 14 and the notches 15 can be made to correspond.

[0098] The position adjustment of the visual component may be performed by interposing a spacer between the base and a fixing member such as a collar. If the visual component has only one side, the position may be adjusted by forming a plurality of female screw holes at different positions in the axial direction in the one side and fixing a bolt inserted through a selected female screw hole to the fixing member in the radial direction. In this way, the configuration of the position adjustment means may be changed as appropriate. EXAMPLES

[0099] Next, a mechanical seal according to a third embodiment will be described with reference to Fig. 6. Note that a description of the same configuration as in the first embodiment will be omitted.

[0100] The mechanical seal 201 of the third embodiment is mainly composed of a stationary element Q2 and a rotating element R2.

[0101] The rotating element R2 includes a bellows 206 having a rotating seal ring 260, a clamp 207 as a fixing member, a retainer 208, a coil spring 9 as a biasing means, a collar 209, and a visual component 10.

[0102] The bellows 206 is formed in a substantially cylindrical shape and includes, from the right side, a rotating seal ring 260, a bellows portion 261, and a base end portion 262.

[0103] Bellows portion 261 is formed in a bellows shape and is configured to be expandable and contractible in the axial direction. Base end portion 262 is configured in a cylindrical shape. Bellows portion 261 and base end portion 262 are metal molded products or resin molded products, and bellows portion 261 is fixed to rotating seal ring 260 by an appropriate fixing method such as bonding or welding. Furthermore, bellows portion 261 and rotating seal ring 260 may be integrally molded products made of the same material, and the configuration of bellows 206 may be changed as appropriate.

[0104] The clamp 207 includes a pair of split clamp pieces 270 and two bolts 271. The split clamp pieces 270 are formed in a semicircular arc shape. For convenience of illustration, only one of the pair of split clamp pieces 270 and one of the two bolts 271 are shown in Fig. 6.

[0105] The pair of split clamp pieces 270 are fastened by two bolts 271 while being fitted onto the base end portion 262 of the bellows 206. As a result, the clamp 207 is hermetically fixed by crimping the base end portion 262 onto the rotating shaft 3. Although detailed illustration is omitted, by fastening the split clamp pieces 270 together, the clamp 207 is fixed to the collar 209 in a state in which its relative movement is restricted.

[0106] An annular adaptor 272 is fixed to the clamp 207. In addition, a knock pin 72 is fixed to the adaptor 272.

[0107] The retainer 208 is formed in a cylindrical shape with a step on the inner diameter side.

[0108] The right end inner diameter side of retainer 208 is expanded in diameter so that rotary seal ring 260 can be fitted therein. In addition, retainer 208 and rotary seal ring 260 are able to rotate together as a notched recess formed in the right end face of retainer 208 engages with an outer diameter side protrusion of rotary seal ring 260.

[0109] A plurality of first recesses 208a and a plurality of second recesses 208b that are recessed in the axial direction and open toward the left side are formed on the left end surface of the retainer 208. One end of the coil spring 9 is inserted into the first recess 208a, and the coil spring 9 is disposed between the retainer 208 and the adapter 272 in a state of being compressed in the axial direction.

[0110] Further, one end of the knock pin 72 fixed to the adapter 272 is inserted into a second recess 208 b of the retainer 208 so that the retainer 208 can rotate together with the clamp 207 .

[0111] As a result, the retainer 208 is permitted to move in the axial direction, while rotating together with the clamp 207 in response to the rotation of the rotating shaft 3. In addition, the rotating seal ring 260, which receives the biasing force of the coil spring 9 via the retainer 208, is pressed against the stationary seal ring 205.

[0112] The collar 209 is formed in a cylindrical shape. The collar 209 is fixed to the rotating shaft 3 by a set screw 290 that penetrates the collar 209 in the radial direction and is pressed against the rotating shaft 3.

[0113] The visual component 10 is fixed to the split clamp piece 270 by a bolt 13. Furthermore, the piece 12 of the visual component 10 extends approximately parallel to the outer peripheral surface 208c of the retainer 208. Furthermore, the visual object in this embodiment is an edge 208d where the outer peripheral surface 208c of the retainer 208 and the left axial end face of the retainer 208 intersect.

[0114] As described above, the rotating side element R2 of this embodiment has a configuration in which the rotating seal ring 260 is cantilevered by the clamp 207 via the bellows portion 261 and the base end portion 262. Even with this configuration, the amount of wear of the stationary seal ring 205 and the rotating seal ring 260 can be easily grasped by changing the position of the edge 208d of the retainer 208 visible through the hole 14 and the notch 15 in the visual component 10.

[0115] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0116] For example, in the above-mentioned Examples 1 to 3, the visual component is described as being provided on the rotating side element, but this is not limited to this, and the visual component may be provided on the sealing element in which the biasing means is arranged, and when the biasing means is arranged on the stationary side element, the visual component may be provided on the stationary side element.

[0117] In addition, in the above-mentioned Examples 1 to 3, the visual component has been described as being one-sided, but this is not limited thereto and may be cylindrical. In such a configuration, it is preferable that the visual component is composed of multiple members, such as being split in half, in that it is easier to attach it to the mechanical seal later than a configuration in which it is integrally formed.

[0118] In addition, in the above-mentioned Examples 1 to 3, the visual component has been described as having a base and a piece, but this is not limited thereto, and the visual component may be configured to have only the piece without the base. In such a configuration, the visual component can be fixed to the fixed member by a method such as fixing the piece to the fixed member with a bolt that penetrates the piece in the radial direction, or fixing the piece to the fixed member by welding or the like.

[0119] In the first to third embodiments, the visual component is disposed on the outer diameter side of the rotary seal ring, but the present invention is not limited to this and the visual component may be disposed on the inner diameter side of the rotary seal ring. In such a configuration, it is preferable that the piece of the visual component extends along the inner peripheral surface of the rotary seal ring, which is the side to be visually inspected.

[0120] In addition, in the above-mentioned Examples 1 to 3, the visual component is described as having both a hole and a notch, but the present invention is not limited to this, and only one of the hole and the notch may be provided. Furthermore, a visual component provided with only a hole and a visual component provided with only a notch may be assembled.

[0121] In addition, in the above embodiments 1 to 3, the notches are described as being open toward the rotating seal ring side, but this is not limited thereto, and the notches may be open toward one or the other circumferential side, or may be open toward the rotating seal ring side and one or the other circumferential side.

[0122] In addition, in the above-described embodiments 1 to 3, the notch is formed closer to the rotating seal ring in the axial direction than the hole, but this is not limited to the above, and the hole may be formed closer to the rotating seal ring in the axial direction than the notch.

[0123] In addition, in the above-mentioned first to third embodiments, the hole and the notch are described as being out of phase with each other in the circumferential direction, but the present invention is not limited thereto, and the hole and the notch may be formed in the same phase, i.e., on the same axis. With such a configuration, the circumferential dimension of the one-sided visual component can be shortened.

[0124] In addition, in the above-mentioned first to third embodiments, the hole or notch penetrating in the radial direction is described as an example of the sight window, but the present invention is not limited thereto, and the hole or notch may be embedded in a transparent resin material, glass material, etc., or the part overlapping with the visual target in the radial direction or the whole may be formed of a transparent resin material, glass material, etc., and may be appropriately changed as long as the visual target can be visually recognized. In other words, the sight window does not have to penetrate in the radial direction.

[0125] In addition, in the above-mentioned Examples 1 to 3, a rotating seal ring and a retainer are given as examples of components having a visual object, but the present invention is not limited to these, and may be modified as appropriate as long as the component is a sealing element that is arranged to be able to move axially relative to the fixed member when subjected to the biasing force of the biasing means.

[0126] In addition, in the above-described first to third embodiments, the biasing means is described as a coil spring, but this is not limited thereto, and it may be a coiled wave spring, or rubber, or the bellows portion in the third embodiment may double as the biasing means, or any of these may be combined, or may be modified as appropriate.

[0127] In addition, in the above-described Examples 1 to 3, the bolts for fixing the visual component to the fixed member are described as being inserted in the axial direction, but this is not limited to this, and they may be inserted in the radial direction or the circumferential direction, or any combination of these, or may be modified as appropriate.

[0128] Furthermore, as long as the bolt that fixes the visual component to the fixed member is inserted radially or circumferentially, the hole in the visual component through which the bolt is inserted may be an elongated hole extending axially. With this configuration, the visual component can slide axially while being guided by the bolt inserted into the elongated hole, so that the fixed position of the visual component can be set arbitrarily. [Explanation of symbols]

[0129] 1 Mechanical seal 5 Static seal ring (sealing material) 6 Rotating seal ring (one of the sealing components, component with visual target) 6c Outer surface (side of component having visual target) 6d Edge (visible object) 7 Collar (fixing member) 9 Coil spring (biasing means) 10 Visible Parts 12 pieces 14 holes (sight window) 15 Notch (view window) 112~312 pieces 114~314 holes (sight window) 115~315 Notch (view window) 110 Visible parts 111b Small inner diameter female screw hole (position adjustment means) 116 Small diameter bolt (position adjustment means) 201 Mechanical seal 205 Static seal ring (sealing material) 207 Clamp (fixing member) 208 Retainer (part with visible object) 208c Outer periphery (side of component having visible object) 208d Edge (visible target) 260 Rotating seal ring (one of the seal members) Q1,Q2 Stationary side element R1, R2 Rotating element

Claims

1. A pair of sealing elements that rotate relative to one another; One of the seal elements is a mechanical seal in which a seal member biased by a biasing means is movable in an axial direction relative to a fixed member that fixes the seal member, A mechanical seal comprising a visual component fixed to the fixed member and having a sight window through which a visual object that is part of one of the seal elements can be viewed from the side.

2. 2. The mechanical seal according to claim 1, wherein the visual component has a piece extending from the fixed member side along a side of the member having the visual object, and the sight hole is formed in the piece.

3. The mechanical seal according to claim 1 , wherein the visual component is fixed to the fixed member so that its position can be adjusted in the axial direction.

4. 2. The mechanical seal according to claim 1, wherein the visually inspected object is an edge of a member constituting the one seal element.

5. The mechanical seal according to claim 1 , wherein the sight glass has a shape in which its width in the axial direction varies.

6. 6. The mechanical seal according to claim 5, wherein the sight hole has a circular shape.

7. The mechanical seal according to claim 1 , wherein the sight glass is at least one of a hole and a notch.

8. The mechanical seal according to claim 7 , wherein the hole and the notch are provided at different positions in the axial direction.

9. 9. The mechanical seal according to claim 1, wherein a plurality of the observation windows are provided in the circumferential direction.

Images