Sealing structure

Abstract

To realize a sealing structure that can properly seal the area around the rotating shaft. [Solution] The sealing structure comprises a cylindrical seal member 1 that seals the outer peripheral surface of a rotating shaft 8, and a ring-shaped fastening member 2 that is arranged radially outward of the seal member 1 in the radial direction R and fastens the seal member 1 to the rotating shaft 8. The seal member 1 is flexible. The fastening member 2 is configured so that a plurality of fastening pieces 20 are connected in the circumferential direction C to form a ring shape. A notch 22 that extends over the entire circumferential direction C is formed on the inner peripheral surface of the fastening member 2 in the radial direction R. A ring-shaped pressing member 3 that presses against the seal member 1 is arranged in the notch 22.

Description

[Technical Field]

[0001] The present invention relates to a sealing structure around a rotating shaft. [Background technology]

[0002] Mechanical seals installed in rotating equipment such as mixers and pumps form a sealing surface by sliding between a fixed ring and a rotating ring arranged opposite each other in the axial direction, sealing around the rotating shaft and preventing fluid leakage (see, for example, JP 2024-155070 A).

[0003] In mechanical seals, a sealing structure is also used in the secondary seal portion, which is a sealing location other than the above-mentioned seal surface. For example, Figures 5 and 6 show a shaft seal structure that can be used in the secondary seal portion. In the illustrated shaft seal structure, a cylindrical seal member 98 is provided to cover the outer peripheral surface of a rotating shaft 99. A fastening member 97 is disposed radially outward of the seal member 98, and this fastening member 97 fastens the seal member 98 to the rotating shaft 99.

[0004] The fastening member 97, which is attached to the rotary shaft 99 and the seal member 98 from the radially outer side, has a structure including divided pieces 97a that are divided in the circumferential direction, as shown in Fig. 6. These divided pieces 97a are connected with bolts 96, so that the fastening member 97 forms an annular shape and is arranged to cover the entire circumference of the seal member 98.

[0005] The seal member 98 is made of a flexible resin material such as an elastomer. Therefore, when the fastening member 97 is attached to the seal member 98, the seal member 98 may bend and become caught between the divided pieces 97a that are adjacent in the circumferential direction. This bending creates a gap G between the rotating shaft 99 and the seal member 98. This gap G can be a cause of fluid leakage. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-155070 Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above circumstances, there is a need for a sealing structure that can adequately seal the area around the rotating shaft. [Means for solving the problem]

[0008] A sealing structure around a rotation shaft, a cylindrical seal member disposed radially outward of the rotary shaft and sealing an outer peripheral surface of the rotary shaft; a ring-shaped fastening member disposed radially outward of the seal member and fastening the seal member to the rotary shaft, The sealing member is flexible, The fastening member is configured so that a plurality of fastening pieces are connected in a circumferential direction to form a ring shape, A notch portion extending over the entire circumferential direction is formed on a radially inner circumferential surface of the fastening member, A ring-shaped pressure contact member is disposed in the notch portion and is brought into pressure contact with the seal member.

[0009] When connecting multiple fastening pieces in the circumferential direction, it is difficult to avoid gaps between adjacent fastening pieces. However, with this configuration, a notch is formed on the inner peripheral surface of the fastening member so as to extend over the entire circumferential direction, and a pressure-contact member disposed in this notch presses the seal member from the radially outer side. As a result, when a gap occurs between circumferentially adjacent fastening pieces, the pressure-contact member can press the seal member from the radially outer side at the circumferential position where the gap exists. Therefore, even at the position where the gap exists, the seal member can be pressed against the rotating shaft without deflecting, thereby ensuring appropriate sealing around the rotating shaft.

[0010] Further features and advantages of the techniques according to the present disclosure will become more apparent from the following description of exemplary and non-limiting embodiments, which proceeds with reference to the drawings. [Brief explanation of the drawings]

[0011] [Figure 1] Radial view of sealing structure [Figure 2] Axial view of the sealing structure [Figure 3] 10A and 10B are diagrams illustrating sealing members and fastening members according to other embodiments. [Figure 4] 10A and 10B are diagrams showing pressure contact members according to other embodiments; [Figure 5] Diameter view of a conventional sealing structure [Figure 6] Axial view of a conventional sealing structure DETAILED DESCRIPTION OF THE INVENTION

[0012] The sealing structure according to the present disclosure is a sealing structure around a rotating shaft, and is used, for example, in the secondary seal portion of a mechanical seal. In a mechanical seal, fluid leakage is suppressed at the seal surface where a rotating ring and a fixed ring, which are arranged opposite each other in the axial direction, slide against each other, but there are also areas that need to be sealed in places other than the seal surface. These areas that need to be sealed are secondary seal portions, and the sealing structure according to this embodiment can be used in these secondary seal portions. The fluid to be sealed may be a liquid or a gas (for example, a gas generated in a chemical agitator).

[0013] In the following, an embodiment of the sealing structure will be described, with the axis Ax of the rotating shaft 8 as the reference, and the "axial direction L", "radial direction R", and "circumferential direction C" defined.

[0014] As shown in FIG. 1, the sealing structure includes a cylindrical sealing member 1 that is arranged radially outward from the rotating shaft 8 in the radial direction R and seals the outer peripheral surface 8F of the rotating shaft 8, and a ring-shaped fastening member 2 that is arranged radially outward from the sealing member 1 in the radial direction R and fastens the sealing member 1 to the rotating shaft 8.

[0015] The seal member 1 has flexibility and is made of a resin material such as an elastomer resin.

[0016] The fastening member 2 has rigidity and is made of a metal material such as stainless steel.

[0017] As shown in Fig. 2, the fastening member 2 is configured so that a plurality of fastening pieces 20 are connected in the circumferential direction C to form a ring shape. In this embodiment, the fastening member 2 is configured using a pair of semicircular arc-shaped fastening pieces 20. The pair of semicircular arc-shaped fastening pieces 20 are connected in the circumferential direction C, so that the fastening member 2 forms a ring shape.

[0018] In this embodiment, the pair of fastening pieces 20 are connected using a bolt 4. Each fastening piece 20 has a recess 23 in which the bolt 4 is disposed and a bolt insertion hole 24 into which the bolt 4 is inserted.

[0019] The recess 23 is for accommodating the bolt 4 inside the circular outer shape of the fastening member 2, in other words, for preventing the bolt 4 from protruding from the outer shape of the fastening member 2. After the bolt 4 is fastened, the head of the bolt 4 is placed in the recess 23.

[0020] The bolt insertion hole 24 of one fastening piece 20 is disposed at a position corresponding to the recess 23 of the other fastening piece 20. The bolt 4 is inserted from the recess 23 of one fastening piece 20 toward the bolt insertion hole 24 of the other fastening piece 20. The head of the bolt 4 stops in the recess 23 of one fastening piece 20, and the threaded portion of the bolt 4 screws into the bolt insertion hole 24 of the other fastening piece 20. As a result, both fastening pieces 20 are firmly connected.

[0021] Each of the pair of semicircular arc-shaped fastening pieces 20 has two end faces in the circumferential direction C and is connected to each other at two locations in the circumferential direction C. At these connection locations, the end face in the circumferential direction C of one fastening piece 20 and the end face in the circumferential direction C of the other fastening piece 20 face each other in the circumferential direction C with a gap between them. Here, both end faces of the fastening pieces 20 in the circumferential direction C are defined as first end faces 21F.

[0022] The fastening member 2 has a first boundary 21 where the first end faces 21F of a pair of fastening pieces 20 face each other. That is, the first end face 21F of one fastening piece 20 faces the first end face 21F of the other fastening piece 20 in the circumferential direction C, thereby forming one first boundary 21. For the fastening member 2 as a whole, two such first boundaries 21 exist in the circumferential direction C.

[0023] That is, in this embodiment, a pair of first boundaries 21, where the first end faces 21F of a pair of fastening pieces 20 face each other in the circumferential direction C, are positioned at positions that are 180 degrees out of phase with each other in the circumferential direction C and are fastened by bolts 4 that are inserted in a direction perpendicular to the first end faces 21F.

[0024] 5 and 6, when fastening member 97 is attached to seal member 98, seal member 98 may bend and become caught between circumferentially adjacent divided pieces 97a (see FIG. 6). This bending creates a gap G between rotating shaft 99 and seal member 98, and this gap G is a cause of fluid leakage at the secondary seal portion of the mechanical seal.

[0025] The sealing structure according to the present disclosure can prevent the formation of such a gap G and improve the reliability of sealing, as will be described in detail below.

[0026] 1 and 2, in the sealing structure according to the present disclosure, a notch 22 extending over the entire circumferential direction C is formed on an inner circumferential surface 2F (see FIG. 1) in the radial direction R of the fastening member 2. A ring-shaped pressing member 3 that is pressed against the seal member 1 is disposed in this notch 22. In this embodiment, the pressing member 3 is made of a metal material such as stainless steel.

[0027] When connecting multiple fastening pieces 20 in the circumferential direction C, it is inevitable that gaps will occur between adjacent fastening pieces 20. That is, as shown in the figure, a gap occurs in the circumferential direction C at a first boundary 21 where the first end faces 21F of each fastening piece 20 face each other. However, in the sealing structure according to the present disclosure, a notch 22 is formed in the inner circumferential surface 2F of the fastening member 2 so as to extend over the entire circumferential direction C, and the pressure contact member 3 disposed in this notch 22 presses the seal member 1 from the outside in the radial direction R. As a result, when a gap occurs at the first boundary 21, the pressure contact member 3 can press the seal member 1 from the outside in the radial direction R at the position in the circumferential direction C where the gap exists (i.e., the position of the first boundary 21). Therefore, even at the position of the first boundary 21 where the gap exists, the seal member 1 can be pressed against the rotating shaft 8 without being deflected, thereby enabling appropriate sealing around the rotating shaft 8.

[0028] 1, in this embodiment, the crimping member 3 is disposed at a position where it presses against the center of the seal member 1 in the axial direction L. In the illustrated example, a notch 22 for disposing the crimping member 3 is formed in a groove shape at the center of the fastening member 2 in the axial direction L. Therefore, the crimping member 3 disposed in this notch 22 is disposed at the center of the fastening member 2 in the axial direction L, and is therefore disposed at a position where it presses against the center of the seal member 1 in the axial direction L. This configuration makes it easier to uniformly press the seal member 1 over the entire axial direction L.

[0029] As shown in FIG. 2, the crimping member 3 is configured so that a plurality of crimping pieces 30 are arranged in the circumferential direction C to form a ring shape. In this embodiment, the crimping member 3 is configured using a pair of semicircular arc-shaped crimping pieces 30. Because the crimping member 3 is configured using a plurality of crimping pieces 30, the crimping member 3 can be appropriately positioned on the outer periphery of the cylindrical sealing member 1. Furthermore, because the plurality of crimping pieces 30 are a pair of semicircular arc-shaped crimping pieces 30, when the entire crimping member 3 is positioned in the cutout portion 22, it is only necessary to attach the crimping pieces 30 twice. This also improves workability.

[0030] Each of the pair of semicircular arc-shaped press-connecting pieces 30 has two end faces in the circumferential direction C, and they face each other at two locations in the circumferential direction C. At these facing locations, the end face in the circumferential direction C of one press-connecting piece 30 and the end face in the circumferential direction C of the other press-connecting piece 30 face each other in the circumferential direction C with a gap between them. Here, the end face in the circumferential direction C of each press-connecting piece 30 is defined as a second end face 32F.

[0031] The press-connecting member 3 has a second boundary 32 where the second end faces 32F of a pair of press-connecting pieces 30 face each other. That is, the second end face 32F of one press-connecting piece 30 faces the second end face 32F of the other press-connecting piece 30 in the circumferential direction C, thereby forming one second boundary 32. The press-connecting member 3 as a whole has two such second boundary parts 32 in the circumferential direction C.

[0032] In this embodiment, a plurality of first boundary portions 21 where the first end faces 21F in the circumferential direction C of a plurality of fastening pieces 20 face each other, and a plurality of second boundary portions 32 where the second end faces 32F in the circumferential direction C of a plurality of pressure-welding pieces 30 face each other are arranged at different positions in the circumferential direction C.

[0033] With this configuration, a part of the press-contact piece 30 can be disposed at the position of the first boundary 21, i.e., at the position in the circumferential direction C where the boundary between the fastening pieces 20 is located. On the other hand, a part of the fastening piece 20 can be disposed at the position of the second boundary 32, i.e., at the position in the circumferential direction C where the boundary between the fastening pieces 30 is located. This allows the fastening member 2 and the press-contact member 3 to function complementarily with each other, making it possible to press the seal member 1 against the rotating shaft 8 all around in the circumferential direction C.

[0034] Furthermore, in this embodiment, a pair of second boundaries 32, where the second end faces 32F of the pair of press-fit pieces 30 in the circumferential direction C face each other, are arranged at positions that are 180 degrees out of phase with each other in the circumferential direction C. The first boundaries 21, which are the boundaries between the fastening pieces 20, and the second boundaries 32, which are the boundaries between the press-fit pieces 30, are arranged at positions that are 90 degrees out of phase with each other.

[0035] With this configuration, the distance in the circumferential direction C from the first boundary 21 to the second boundary 32 is maximized, thereby enhancing the complementary function between the fastening member 2 and the pressure-contact member 3, making it easier to achieve a great sealing effect.

[0036] As described above, the sealing structure according to the present disclosure makes it possible to appropriately seal the area around the rotating shaft 8.

[0037] Other Embodiments Next, other embodiments will be described.

[0038] (1) In the above embodiment, an example has been described in which the notch 22 for disposing the press-fit member 3 is formed in a groove shape at the center of the fastening member 2 in the axial direction L. However, the present invention is not limited to this example. For example, FIG. 3 shows a seal member 100 and a fastening member 200 according to another embodiment. In the example shown in FIG. 3, the fastening member 200 has a stepped notch 202. The notch 202 is provided at an end of the fastening member 200 in the axial direction L and has a stepped shape. The seal member 100 also has a sealing portion 101 that is disposed between the rotating shaft 8 and the fastening member 200 in the radial direction R and seals in the fluid, and a retaining portion 102 that protrudes outward from the sealing portion 101 in the radial direction R and retains the press-fit member 3 from the axial direction L. The retaining portion 102 is formed in a flange shape that extends over the entire circumferential direction C. As a result, even in a configuration in which the pressing member 3 is disposed in the stepped cutout portion 202, the pressing member 3 can be appropriately held by the holding portion 102 of the seal member 100. Note that the holding portion 102 does not have to be formed over the entire circumferential direction C, and may be formed intermittently in the circumferential direction C.

[0039] (2) In the above embodiment, an example was described in which both the fastening member 2 in which the notch 22 is formed and the press-fit member 3 placed in the notch 22 are made of metal. In this configuration, it is difficult to arrange the press-fit member 3 without a gap relative to the notch 22 from a design perspective (gaps occur due to tolerances). In this case, fluid that enters between the notch 22 and the press-fit member 3 may flow through the notch 22 in the circumferential direction C to the second boundary 32 and then further flow in the circumferential direction C to the first boundary 21. That is, the fluid may flow through the notch 22, the second boundary 32, and the first boundary 21 and leak. In light of this, as shown in FIG. 4 , the press-fit member 300 may be made of a hard resin with a predetermined elasticity instead of a metal material. Because the press-fit member 300 has elasticity, it can be arranged without a gap relative to the notch 22. In this example, the pressure contact member 300 includes a first surface portion 301 that contacts the seal member 1, and a second surface portion 302, a third surface portion 303, and a fourth surface portion 304 that contact the cutout portion 22. This prevents gaps from occurring inside the cutout portion 22, making it possible to further suppress fluid leakage.

[0040] (3) In the above embodiment, an example has been described in which the bolt 4 connecting the pair of fastening pieces 20 is inserted in a direction perpendicular to the first end surface 21F. However, this is not limited to such an example. The bolt 4 may be configured to be inserted obliquely with respect to the first end surface 21F.

[0041] (4) In the above embodiment, the bolts 4 are used to connect the multiple fastening pieces 20 together. However, the present invention is not limited to this example. Instead of the bolts 4, the multiple fastening pieces 20 may be connected together using clamps or the like.

[0042] (5) In the above embodiment, an example has been described in which the fastening member 2 is configured using a pair of semicircular arc-shaped fastening pieces 20. However, the present invention is not limited to such an example. The fastening member 2 may be configured using three or more fastening pieces 20.

[0043] (6) In the above embodiment, an example has been described in which the press-contact member 3 is configured using a pair of semicircular arc-shaped press-contact pieces 30. However, the present invention is not limited to this example. The press-contact member 3 may be configured using three or more press-contact pieces 30.

[0044] (7) The configurations disclosed in the above-described embodiments may be combined with configurations disclosed in other embodiments as long as no contradictions arise. Regarding other configurations, the embodiments disclosed in this specification are merely examples in all respects. Therefore, various modifications may be made as appropriate within the scope of the present disclosure.

[0045] [Summary of this embodiment] The summary of this embodiment will be described below.

[0046] A sealing structure around a rotation shaft, a cylindrical seal member disposed radially outward of the rotary shaft and sealing an outer peripheral surface of the rotary shaft; a ring-shaped fastening member disposed radially outward of the seal member and fastening the seal member to the rotary shaft, The sealing member is flexible, The fastening member is configured so that a plurality of fastening pieces are connected in a circumferential direction to form a ring shape, A notch portion extending over the entire circumferential direction is formed on a radially inner circumferential surface of the fastening member, A ring-shaped pressure contact member is disposed in the notch portion and is brought into pressure contact with the seal member.

[0047] When connecting multiple fastening pieces in the circumferential direction, it is difficult to avoid gaps between adjacent fastening pieces. However, with this configuration, a notch is formed on the inner peripheral surface of the fastening member so as to extend over the entire circumferential direction, and a pressure-contact member disposed in this notch presses the seal member from the radially outer side. As a result, when a gap occurs between circumferentially adjacent fastening pieces, the pressure-contact member can press the seal member from the radially outer side at the circumferential position where the gap exists. Therefore, even at the position where the gap exists, the seal member can be pressed against the rotating shaft without deflecting, thereby ensuring appropriate sealing around the rotating shaft.

[0048] The pressure contact member is configured so that a plurality of pressure contact pieces are arranged in a circumferential direction to form a ring shape, It is preferable that a plurality of first boundary portions where the first circumferential end faces of the plurality of fastening pieces face each other, and a plurality of second boundary portions where the second circumferential end faces of the plurality of pressure-welding pieces face each other, are arranged at different circumferential positions.

[0049] According to this configuration, a portion of the press-fitting piece can be positioned at the first boundary, i.e., at the circumferential position where the boundary between the fastening pieces is located. Meanwhile, a portion of the fastening piece can be positioned at the second boundary, i.e., at the circumferential position where the boundary between the fastening pieces is located. Therefore, according to this configuration, the fastening member and the press-fitting member function complementarily with each other, making it possible to press the seal member against the rotating shaft over the entire circumferential direction. This facilitates improved sealing performance.

[0050] The fastening member is configured using a pair of semicircular arc-shaped fastening pieces, It is preferable that a pair of first boundaries where the circumferential first end faces of the pair of fastening pieces face each other are positioned at positions that are 180 degrees out of phase with each other in the circumferential direction and are fastened by bolts inserted in a direction perpendicular to the first end faces.

[0051] According to this configuration, workability is improved when attaching the fastening member to the rotating shaft.

[0052] The pressure contact member is configured using a pair of semicircular arc-shaped pressure contact pieces, a pair of second boundary portions where second end surfaces of the pair of press-fit pieces face each other in the circumferential direction are arranged at positions that are out of phase with each other by 180 degrees in the circumferential direction, Preferably, the first boundary and the second boundary are disposed at positions that are out of phase with each other by 90 degrees.

[0053] According to this configuration, by maximizing the circumferential distance from the first boundary to the second boundary, the complementary function between the fastening member and the press-contact member can be enhanced, making it easier to obtain a great sealing effect. [Industrial Applicability]

[0054] The technology according to the present disclosure can be used in a sealing structure around a rotating shaft. [Explanation of symbols]

[0055] 1: Sealing material 2: Fastening member 2F: Inner surface 20: Fastening piece 21: First boundary 21F: 1st end surface 22: Notch 3: Pressure welding material 30: Pressure welding piece 32: Second boundary 32F: 2nd end surface 4: Bolt 8: Rotation axis 8F: Outer surface L: Axial direction R: Radial direction C: Circumferential direction

Claims

1. A sealing structure around a rotation shaft, a cylindrical seal member disposed radially outward of the rotary shaft and sealing an outer peripheral surface of the rotary shaft; a ring-shaped fastening member disposed radially outward of the seal member and fastening the seal member to the rotary shaft, The sealing member is flexible, The fastening member is configured so that a plurality of fastening pieces are connected in a circumferential direction to form a ring shape, A notch portion extending over the entire circumferential direction is formed on a radially inner circumferential surface of the fastening member, a ring-shaped pressure contact member that is in pressure contact with the seal member is disposed in the notch portion; The pressure contact member is configured so that a plurality of pressure contact pieces are arranged in a circumferential direction to form a ring shape, A sealing structure in which a plurality of first boundary portions where the first circumferential end faces of the plurality of fastening pieces face each other, and a plurality of second boundary portions where the second circumferential end faces of the plurality of pressure-welding pieces face each other, are arranged at different circumferential positions.

2. The fastening member is configured using a pair of semicircular arc-shaped fastening pieces, 2. The sealing structure according to claim 1, wherein a pair of first boundaries where the first end faces of the pair of fastening pieces face each other are positioned 180 degrees out of phase with each other in the circumferential direction and are fastened by bolts inserted in a direction perpendicular to the first end faces.

3. A sealing structure around a rotation shaft, a cylindrical seal member disposed radially outward of the rotary shaft and sealing an outer peripheral surface of the rotary shaft; a ring-shaped fastening member disposed radially outward of the seal member and fastening the seal member to the rotary shaft, The sealing member is flexible, The fastening member is configured so that a plurality of fastening pieces are connected in a circumferential direction to form a ring shape, A notch portion extending over the entire circumferential direction is formed on a radially inner circumferential surface of the fastening member, a ring-shaped pressure contact member that is in pressure contact with the seal member is disposed in the notch portion; The fastening member is configured using a pair of semicircular arc-shaped fastening pieces, a pair of first boundaries where first end surfaces of the pair of fastening pieces face each other in the circumferential direction are arranged at positions that are 180 degrees out of phase with each other in the circumferential direction and are fastened by bolts that are inserted in a direction perpendicular to the first end surfaces, The pressure contact member is configured using a pair of semicircular arc-shaped pressure contact pieces, a pair of second boundaries at which second end surfaces of the pair of press-fit pieces face each other in the circumferential direction are disposed at positions that are out of phase with each other by 180 degrees in the circumferential direction, A sealing structure, wherein the first boundary and the second boundary are positioned at positions that are out of phase with each other by 90 degrees.

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