Shaft seal device

Abstract

The present invention provides a shaft sealing device in which leaks into a leak-side space of a sealed fluid can easily be repaired.　The present invention pertains to a shaft sealing device 1 having: a mating ring 5 which has a sliding surface 51 and is attached to a case 4 through which a rotary shaft 3 passes; and an ordinary seal ring 6 which is attached to the rotary shaft 3 and has a sliding surface 62a which slides with the sliding surface 51 of the mating ring 5, a sealed fluid being sealed by the sliding surfaces 51, 62a, wherein a spare seal ring 7 is provided that has a sliding surface 72a which faces the sealed fluid in the axial direction, the spare seal ring being attached to the rotary shaft 3 on the axial-direction side opposite the sealed fluid with respect to the sliding surface 51 of the mating ring 5 and the sliding surface 62a of the ordinary seal ring 6, and the spare seal ring 7 can move towards the sealed fluid in the axial direction.

Description

[Technical Field]

[0001] The present invention relates to a shaft sealing device that seals a rotating shaft. [Background technology]

[0002] As shaft sealing devices for preventing leakage of sealed fluids around the rotating shaft of a rotary machine, for example, those that use mechanical seals consisting of a pair of annular sliding parts that rotate relative to each other and whose sliding surfaces slide against each other, and those that use lip seals that rotate and slide relative to the sliding surface of the rotating shaft or housing are known.

[0003] For example, Patent Document 1 discloses a shaft seal device used in a ship's propulsion system. The shaft seal device is configured so that a regular seal ring is slidably arranged in the axial direction from the inboard side of the ship in a case attached to a stern tube through which a rotating shaft equipped with a propeller is inserted. The regular seal ring is attached to a step on one axial end of a clamp ring fixed to the rotating shaft, and a spare seal ring is attached to a step on the other axial end of the clamp ring. Furthermore, a lip seal is arranged outboard of the regular seal ring. By allowing seawater to flow outboard, the lip seal does not come into contact with the rotating shaft, allowing the regular seal to seal out the seawater. By stopping the flow of seawater, the lip seal comes into contact with the rotating shaft and can seal out the seawater.

[0004] The sealing performance of the regular seal ring may deteriorate due to wear over time, causing the sealed fluid to leak into the ship's interior. In the shaft seal device of Patent Document 1, in an emergency like the one described above, the rotation of the rotating shaft is stopped, and while the lip seal seals against seawater leaking into the ship's interior, the regular seal ring is removed from the clamp ring and a spare seal ring is attached to a step on one axial end of the clamp ring for repair. The rotating shaft is then rotated, allowing seawater to flow outboard, where it is sealed by the spare seal ring. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Microfilm of Utility Model Application No. 1-32985 (Utility Model Application No. 2-124374) (page 10, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0006] In the shaft seal device of Patent Document 1, the repair work required removing the regular seal ring, whose sealing performance had deteriorated, from the clamping ring, and then expanding the diameter of the spare seal ring and moving it from the step at the other end of the clamping ring to the step at one end, making the repair work complicated.

[0007] The present invention has been made in view of the above-mentioned problems, and has as its object to provide a shaft seal device that can easily repair leakage of the sealed fluid into the space on the leakage side. [Means for solving the problem]

[0008] In order to solve the above problems, the shaft seal device of the present invention comprises: A shaft seal device comprising: a mating ring having a sliding surface and attached to a case through which a rotating shaft is inserted; a regular seal ring having a sliding surface that slides against the sliding surface of the mating ring and attached to the rotating shaft; and a shaft seal device that seals against a sealed fluid by means of these sliding surfaces, the shaft seal device includes a spare seal ring attached to the rotating shaft on the opposite axial side of the sealed fluid relative to the sliding surfaces of the mating ring and the regular seal ring, the spare seal ring having a sliding surface facing the sealed fluid in the axial direction; The spare seal ring is movable in the axial direction toward the sealed fluid. According to this, in an emergency when a malfunction occurs in the regular seal ring, the spare seal ring can be moved toward the sealed fluid, thereby allowing the spare seal ring to seal the sealed fluid, thereby easily performing emergency repairs for leakage of the sealed fluid into the space on the leakage side.

[0009] The spare seal ring may be attached to the rotary shaft by a fastening means capable of adjusting the fastening force. This allows the spare seal ring to be easily moved along the rotating shaft by loosening the fastening means, and the spare seal ring can be fixed to the rotating shaft by tightening the fastening means.

[0010] The regular seal ring and the spare seal ring may be the same component and may be arranged inverted relative to each other. According to this, since the regular seal ring and the spare seal ring are the same part, the structure is simple and installation errors are unlikely to occur.

[0011] A flow path for supplying the sealed fluid from the outside may be connected to the sealed fluid side space inside the case in which the conventional seal ring is disposed. This allows a flow of the sealed fluid to occur near the mating ring and the regular seal ring, preventing contaminants from accumulating near the sliding surfaces of the mating ring and the regular seal ring. Therefore, even in a situation where a malfunction occurs in the regular seal ring and contamination is relatively likely to occur, contamination can be prevented from entering between the sliding surface of the spare seal ring and another sliding surface of the mating ring.

[0012] The shaft seal device may be a water-lubricated stern tube shaft seal device. This can prevent overboard water from entering the ship in an emergency. [Brief explanation of the drawings]

[0013] [Figure 1]1 is a cross-sectional view of a shaft sealing device according to a first embodiment of the present invention. [Figure 2] 1 is an enlarged cross-sectional view of a main part of a shaft sealing device according to a first embodiment of the present invention. [Figure 3] FIG. 6 is an enlarged cross-sectional view of a main part of a shaft sealing device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A shaft sealing device according to an embodiment of the present invention will be described below with reference to the accompanying drawings. [Example]

[0015] A shaft seal device according to a first embodiment will be described with reference to Fig. 1 and Fig. 2. In the following description, the left and right sides of Fig. 1 will be referred to as the left and right sides of the shaft seal device. More specifically, the side where the spare seal ring 7 is arranged will be referred to as the right side, and the opposite side will be referred to as the left side.

[0016] As shown in Fig. 1, the shaft seal device 1 is a water-lubricated stern tube shaft seal device that is applied to the inboard side of a propulsion device, which is the leakage side space S2 of a ship, and seals a rotating shaft 3 that passes through a cylindrical housing 2. The shaft seal device 1 may be applied not only to ships but also to rotating machines such as automobiles and general industrial machines.

[0017] A propeller for propulsion is attached to the outboard end of the rotating shaft 3, i.e., the left axial end (not shown), and a stern tube bearing (not shown) that supports the rotating shaft 3 is arranged near the propeller.

[0018] The shaft seal device 1 is mainly composed of a case 4, a mating ring 5, a seal ring 6, and a spare seal ring 7.

[0019] The case 4 has a flanged cylindrical shape including a tubular portion 40 extending outboard and a flange 41 extending radially outward from the right end of the tubular portion 40 in the axial direction.

[0020] The cylindrical portion 40 of the case 4 is fitted into the joint hose 20 and fixed by a clamping ring 21. The right end portion of the housing 2 in the axial direction is fitted into the joint hose 20 and fixed by a clamping ring 21.

[0021] A through hole 42 penetrating in the axial direction is formed in the case 4. More specifically, the through hole 42 has a small diameter hole portion 43 extending from the axial left end face of the cylindrical portion 40 toward the axial right side, and a large diameter hole portion 44 extending toward the axial right side and defining a space S1 on the sealed fluid side, and the small diameter hole portion 43 and the large diameter hole portion 44 are connected to an annular inner end face 49 extending in the radial direction.

[0022] In addition, multiple grooves 45 are formed in the cylindrical portion 40, which open toward the inner diameter side and communicate with space S1 and space S2 on the outside of the ship than the case 4, and the right end surface in the axial direction of the grooves 45 is a tapered surface 45a that expands in diameter toward the right.

[0023] In addition, the case 4 has a communication hole 46 formed therein that communicates with the outer diameter side and inner diameter side of the flange 41 formed at the right end in the axial direction, and the inner diameter side of the communication hole 46 communicates with the space S1.

[0024] The mating ring 5 is an annular stainless steel plate having a through passage 50 penetrating in the axial direction, and the inner diameter side end of the left axial end face is a sliding surface 51 against which the sliding surfaces 62a, 63a of the regular seal ring 6 slide, and the inner diameter side end of the right axial end face is a sliding surface 52 as another sliding surface against which the sliding surfaces 72a, 73a of the spare seal ring 7 can slide. Note that the mating ring 5 is not limited to being made of stainless steel.

[0025] The mating ring 5 is attached to the case 4 by inserting the male thread portion Ba of the bolt B, which is inserted into the washer W, into the multiple equally spaced axial through holes 53 at the outer diameter end and the axial through hole 47 that penetrates the flange 41 of the case 4 in the axial direction, and then screwing in the double nuts N1 and N2.

[0026] Furthermore, when the shaft seal device 1 is in use with the double nuts N1, N2 screwed together, the left axial end 60b of the seal ring 6 abuts against the inner end face 49 of the case 4, and the seal ring 6 is assembled to the case 4 with the sliding surface 51 abutting against the sliding surfaces 62a, 63a of the seal ring 6 so as to be able to slide relative to the sliding surfaces. Note that when the shaft seal device 1 is in use, the left axial end 60b of the seal ring 6 and the inner end face 49 of the case 4 may be slightly spaced apart.

[0027] In addition, an O-ring P is placed between the case 4 and the mating ring 5 in an annular groove 48 recessed from the axial right end face of the flange 41 of the case 4 toward the axial left side, thereby preventing seawater introduced into the through hole 42 from leaking inside the ship.

[0028] 2, the regular seal ring 6 is made of nitrile rubber and has a cylindrical mounting portion 60 and a large-diameter sealing portion 61 that extends radially outward from the mounting portion, and is formed into an annular shape with a thin lip 62 that curves and extends obliquely toward the outer diameter on the inner diameter side of the sealing portion 61, and a support leg 63 that is thicker than the lip 62 and is provided on the outer diameter side of the lip 62. Note that the regular seal ring 6 is not limited to being made of nitrile rubber.

[0029] The right end surface of the lip 62 in the axial direction is a sliding surface 62a, and the right end surface of the support leg 63 is a sliding surface 63a. Since the support leg 63 mainly receives axial force, the lip 62 is more likely to exhibit sealing properties.

[0030] In addition, the support leg 63 has multiple equally spaced communicating grooves 63b that connect the right axial end in the radial direction, and the communicating grooves 63b communicate with an annular groove 64 formed between the lip 62 and the support leg 63.

[0031] The regular seal ring 6 is fitted onto the rotating shaft 3, and is fixed to the rotating shaft 3 by fitting a garter spring 8 into an annular groove 60a recessed on the outer diameter side of the mounting portion 60. The regular seal ring 6 is also disposed within the large diameter hole portion 44 of the case 4.

[0032] The spare seal ring 7 has the same configuration as the seal ring 6, and is disposed opposite to and inverted with respect to the seal ring 6. For the sake of convenience, common descriptions will be omitted.

[0033] The regular seal ring 6 and the spare seal ring 7 are the same part and can be used interchangeably, so the structure of the shaft seal device 1 can be simplified and assembly errors are less likely to occur.

[0034] As shown in Figures 1 and 2, under normal circumstances, that is, when the regular seal ring 6 is functioning sufficiently and no fluid is leaking from the regular seal ring 6 to the spare seal ring 7, in other words, into the space S3 inside the ship, the spare seal ring 7 is fixed to the rotating shaft 3 by externally fitting a garter spring 9 as a tightening means with the sliding surfaces 72a, 73a spaced apart from the sliding surface 52 of the mating ring 5.

[0035] Next, the sealing function of the shaft sealing device 1 will be described.

[0036] 1, seawater delivered from outside the ship as a sealed fluid delivered by a pump (not shown) passes through the connector C and the communication hole 46 of the case 4 and is introduced into the through-hole 42 and the space S1.

[0037] As shown by the black arrows in FIG. 2, seawater passes through the communication hole 46 and the through-hole 42 and is discharged outside the ship.

[0038] 2, some of the seawater passes through the communication groove 63b of the seal ring 6 and flows in and out of the annular groove 64. As shown in FIG.

[0039] The seawater in this annular groove 64 presses the lip 62 of the regular seal ring 6 toward the mating ring 5, maintaining a tight contact between the sliding surface 62a of the lip 62 and the sliding surface 51 of the mating ring 5.

[0040] Furthermore, when the rotating shaft 3 moves relative to the case 4 in the axial left direction due to vibration or the like, the axial left end portion 60b of the normal seal ring 6 abuts against the inner end face 49 of the case 4, thereby restricting the normal seal ring 6 from moving excessively in the axial left direction, thereby maintaining a tight contact state between the sliding surface 62a of the lip 62 and the sliding surface 51 of the mating ring 5.

[0041] Furthermore, when the rotating shaft 3 moves relative to the case 4 toward the right in the axial direction, the highly rigid support leg 63 mainly receives the force, and the lip 62 of the regular seal ring 6 is prone to deform toward the annular groove 64, so that the sliding surface 62a of the lip 62 and the sliding surface 51 of the mating ring 5 can be maintained in close contact with each other.

[0042] Furthermore, contaminants and impurities in the annular groove 64 of the regular seal ring 6 are easily discharged from the annular groove 64 through the communicating groove 61b to the space S1 due to the rotational flow of seawater and centrifugal force. In this way, contaminants and impurities that have flowed into the annular groove 64 can be discharged.

[0043] Furthermore, when seawater flows into the groove 45 from the large diameter hole 44 that defines the space S1, it is guided by the tapered surface 45a of the groove 45, so that contaminants and impurities can be quickly discharged outside the ship (not shown).

[0044] Next, we will explain the situation in an emergency, i.e., when seawater introduced into the through hole 42 passes through the through flow path 50 of the mating ring 5 and leaks into the space S3 due to a malfunction such as wear or deterioration over time of the normally used seal ring 6.

[0045] In an emergency, first, rotation of the rotating shaft 3 is stopped. Next, the garter spring 9 is expanded radially outward to loosen the force tightening the rotating shaft 3 against the spare seal ring 7. As shown by the outline arrow in Figure 2, the spare seal ring 7 is moved axially leftward (i.e., toward the sealed fluid) so that the sliding surfaces 72a, 73a of the spare seal ring 7 are brought into close contact with the sliding surface 52 of the mating ring 5. In other words, the axial mounting position of the spare seal ring 7 is adjusted so that it is closer to the mating ring 5. Here, the spare seal ring 7 is spaced axially from the mating ring 5 and is positioned axially away from the sealed fluid relative to the sliding surface 51 of the mating ring 5 and the sliding surfaces 61a, 63a of the seal ring 6.

[0046] Next, the garter spring 9 is again fitted onto the annular groove 70a of the spare seal ring 7, and the spare seal ring 7 is tightened and fixed to the rotating shaft 3, thereby completing the repair work.

[0047] Thereafter, when the rotary shaft 3 is rotated, the sliding surface 72a of the spare seal ring 7 slides and rotates relative to the sliding surface 52 of the mating ring 5 in close contact therewith, thereby sealing the sealed fluid.

[0048] In this way, by using the garter spring 9 as a tightening means during repair work, the spare seal ring 7 can be easily moved and fixed. In addition, emergency repair work is easy because the spare seal ring 7 only needs to be moved in the axial direction without being expanded.

[0049] Furthermore, because the regular seal ring 6 is not removed during repair work, large amounts of seawater do not leak into the space S3 when the spare seal ring 7 is moved. In this way, there is no need to provide a separate annular lip seal that functions during repairs, as in Patent Document 1, and the configuration of the shaft sealing device 1 can be simplified.

[0050] Furthermore, since the spare seal ring 7 is disposed closer to the inside of the ship than the seal ring 6, repair work can be easily carried out from inside the ship.

[0051] Furthermore, during emergency treatment after repairs are completed, the sliding surface 51 of the mating ring 5 and the sliding surfaces 61a, 63a of the seal ring 6 are kept in relative rotational sliding contact, and the sealing performance is supplemented by the spare seal ring 7, minimizing leakage of seawater into the inside of the ship. In other words, seawater can be prevented from entering the ship. [Example]

[0052] Next, a shaft sealing device according to a second embodiment will be described with reference to Fig. 3. Note that the description of the same configuration as in the first embodiment will be omitted.

[0053] The spare seal ring 170 of this second embodiment has a thin lip 172 formed on the inner diameter side of the sealing portion 171 that is approximately U-shaped, more specifically, extends toward the outer diameter, then folds back, and then extends toward the inner diameter and slightly diagonally to the left, and the shape and extending direction of the lip 172 are different from those of the lip 72 of the first embodiment.

[0054] As a result, when emergency measures are taken after repairs are completed, the tip of lip 172 receives force from the sealed fluid toward sliding surface 52, and excellent sealing performance is achieved by sliding surface 172a. Although lip 172 is U-shaped, it may simply extend diagonally from the sealing portion in the inward radial direction and to the left.

[0055] 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.

[0056] For example, in the first and second embodiments, the regular seal ring and the spare seal ring are both lip-type seal rings, but they are not limited to lip-type seal rings and may be, for example, rotary seal rings of a mechanical seal, and may be modified as appropriate.

[0057] Furthermore, in the first embodiment, the regular seal ring and the spare seal ring are described as having the same configuration, but this is not limiting, and the seal rings may have different shapes.

[0058] In addition, in the first and second embodiments, the regular seal ring and the spare seal ring are described as being directly fixed to the rotating shaft, but this is not limiting, and they may be fixed via a sleeve fixed to the rotating shaft, as long as they are rotatable together with the rotating shaft. If a sleeve is used, the spare seal ring can be moved with little force by loosening the fixing means to the rotating shaft during repair, making repair work easier.

[0059] In addition, in the above-described first and second embodiments, the regular seal ring and the spare seal ring are described as being formed in a continuous ring shape, but this is not limited thereto, and they may be formed by assembling multiple divided rings.

[0060] Furthermore, in the first and second embodiments, the tightening means is described as being a garter spring, but this is not limited to this and may be a clamping ring, a pressure ring, a tightening band, or may be modified as appropriate. [Explanation of symbols]

[0061] 1 Shaft sealing device 3 Rotation Axis 4 cases 5 Mating Ring 6 Regular seal ring 7 Spare seal rings 9 Garter spring (tightening means) 51 sliding surface 52 Sliding surface (another sliding surface) 62a sliding surface 72a Sliding surface C Connector (flow path) S1 Space on the sealed fluid side S2 Leak side space S3 Inner space

Claims

1. A shaft seal device comprising: a mating ring having a sliding surface and attached to a case through which a rotating shaft is inserted; a regular seal ring having a sliding surface that slides against the sliding surface of the mating ring and attached to the rotating shaft; and a shaft seal device that seals against a sealed fluid by means of these sliding surfaces, the shaft seal device includes a spare seal ring attached to the rotating shaft on the opposite axial side of the sealed fluid relative to the sliding surfaces of the mating ring and the regular seal ring, the spare seal ring having a sliding surface facing the sealed fluid in the axial direction; The spare seal ring is movable in the axial direction toward the sealed fluid, and the spare seal ring moves axially so that its sliding surface comes into close contact with the sliding surface of the mating ring.

2. 2. A shaft seal device according to claim 1, wherein said spare seal ring is attached to said rotary shaft by means of a clamping means capable of adjusting a clamping force.

3. 3. The shaft seal device according to claim 1, wherein the regular seal ring and the spare seal ring are identical components and are arranged inverted relative to each other.

4. 4. A shaft seal device according to claim 1, wherein a passage for supplying a sealed fluid from the outside is connected to a sealed fluid side space inside said case in which said regular seal ring is disposed.

5. 5. A shaft seal according to claim 1, wherein the shaft seal is a water-lubricated stern tube shaft seal.

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