Seal structures and marine propulsion systems

Abstract

To provide a seal structure configured separately by a seal to prevent oil spillage and by a seal to prevent the seawater from entering, and to provide a ship propulsion unit with the seal structure.SOLUTION: A seal structure 20 is attached to a driving shaft connected to a ship driving unit. The seal structure comprises a seal unit 21 for the seawater to prevent the seawater from entering, and a seal unit 25 for a lubricating oil placed above the seal unit 21 for the seawater via a prescribed space SP and to prevent an oil spillage from the driving unit. At least the seal unit 25 for the lubrication oil is placed in the ship.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a seal structure and a marine propeller.

Background Art

[0002] Conventionally, in a marine propeller in which lubricating oil is used in a drive unit such as an engine or a power transmission mechanism, a seal device attached to a propeller-equipped propulsion shaft (drive shaft) is known to prevent the lubricating oil from flowing out into the ocean or seawater from entering the propeller (see, for example, Patent Document 1).

[0003] A conventional general marine seal device is composed of an oil outflow prevention seal and a seawater intrusion prevention seal in one seal unit. When a problem occurs in such a seal unit, there is a high risk that oil will flow out into the ocean or seawater will enter the propeller. Further, in such a seal unit, it has been structurally difficult to visually confirm the amount of oil leakage or the amount of seawater intrusion when a problem occurs in the seal unit or to monitor changes therein. Furthermore, it has been difficult with the conventional seal structure to restore the seal performance at sea when a problem occurs in the seal unit, and basically it has been necessary to deal with it after the ship is dry-docked. Therefore, a seal structure that can solve such problems has been demanded.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, an object of the present invention is to provide a seal structure in which a seal for preventing oil outflow and a seal for preventing seawater intrusion are separately configured, and a marine propeller equipped with the seal structure. [Means for solving the problem]

[0006] First invention teeth, A seal structure attached to the drive shaft of a ship's propulsion system, which is installed on a ship and obtains propulsion from the ship by drawing in water through an intake port and discharging it overboard through a winding channel, The drive shaft is provided on the upstream side of the flow path and rotates to draw water in from the suction port and generate a water flow in the flow path. The seal structure attached to the drive shaft is A seawater sealing unit to prevent seawater from entering, An oil seal unit is provided, which is positioned on one side of the seawater seal unit with a predetermined space between them, to prevent oil from leaking out of the drive shaft. Equipped with, At least the oil seal unit is located inside the ship, The aforementioned seawater seal unit is equipped with a spare seawater seal that does not normally operate. The aforementioned spare seawater seal is configured to be activated by a predetermined switching operation. It is.

[0008] In the sealing structure of the third invention, The aforementioned spare seawater seal is the seawater seal unit The seawater seal via a removable spacer unit Placed in part of the area, When using the spare seawater seal, the spacer is removed and the spare seawater seal is moved to the other side, thereby activating the spare seawater seal.

[0009] In the seal structure of the fourth invention, One of the spare seawater seals is equipped with a cylindrical seal liner that is attached to the outer surface of the drive shaft, When the spare seawater seal is used, the seal liner is moved to the other side, thereby allowing the spare seawater seal to operate via the seal liner.

[0010] In the seal structure of the fifth invention, the oil seal unit includes a spare oil seal that is not operated under normal conditions.

[0011] In the seal structure of the sixth invention, the spare oil seal is disposed on a part of the oil seal unit via a spacer removable from the oil seal unit and the spare oil seal is operated by removing the spacer and moving the spare oil seal to the other side during use of the spare oil seal.

[0012] In the seal structure of the seventh invention, a cylindrical seal liner attached to the outer peripheral surface of the drive shaft is provided on one side of the spare oil seal, and the spare oil seal is operated through the seal liner by moving the seal liner to the other side during use of the spare oil seal.

[0013] In the seal structure of the eighth invention, the seawater seal unit includes a recovery section for recovering seawater that has entered the ship from the seawater seal, and an alarm generation section that issues a visible and audible alarm when the entered seawater is detected. is what is provided.

[0014] In the seal structure of the ninth invention, the oil seal unit includes a recovery section for recovering oil that has leaked into the ship from the oil seal, and an alarm generation section that issues a visible and audible alarm when the leaked oil is detected. is what is provided.

[0015] The marine propeller of the tenth invention includes any one of the seal structures of the first to the ninth inventions.

Advantages of the Invention

[0016] The seal structure according to the first invention is a seawater seal unit which is arranged via a predetermined space on one side of the unit seal for oil that prevents the outflow of oil from the drive unit. According to such a seal structure, inside the ship, the oil seal unit and the seawater seal unit are configured to be vertically separated via a predetermined space. Therefore, for example, the lubricating oil of the power transmission mechanism such as the gearbox only flows out inside the ship, and it is possible to prevent the oil from flowing out to the outside of the ship (ocean). Further, according to this seal structure, by providing a predetermined space, when a problem occurs in the seal structure, the operator can visually confirm the amount of oil leakage and the amount of seawater intrusion, and can easily monitor changes in them.

[0017] The seal structure according to the second invention includes a standby seawater seal unit that does not operate normally. According to such a seal structure, even when a problem occurs in the seawater seal during use unit , the seal performance can be restored in a short time by operating the standby seawater seal. unit

[0018] L The seal structure according to the third invention is such that when the standby seawater seal is used, the spacer is removed and the standby seawater seal is moved to the other side, so that the standby seawater seal operates. According to such a seal structure, even if the seal performance deteriorates on the open sea, the standby seawater seal can be easily used by removing the spacer. Thereby, the seal performance can be easily restored on the open sea without dry-docking the ship.

[0019] The seal structure according to the fourth invention is such that when the standby seawater seal is used, the seal liner is moved to the other side, so that the standby seawater seal operates via the seal liner. According to such a seal structure, even if the seal performance deteriorates on the open sea, the standby seawater seal can be easily used. Thereby, the seal performance can be easily restored on the open sea without dry-docking the ship.

[0020] The fifth invention relates to a seal structure which includes a spare oil seal that is not normally activated when an oil seal is used. unit It is equipped with such a seal structure, the oil seal in use unit Even if a malfunction occurs, the sealing performance can be restored in a short time by activating the spare oil seal.

[0021] The seal structure according to the sixth invention allows the spare oil seal to be activated by removing the spacer and moving the spare oil seal to the other side when using the spare oil seal. With this seal structure, even if the sealing performance deteriorates at sea, the spare oil seal can be easily used by removing the spacer. This makes it possible to easily restore the sealing performance at sea without having to dry-dock the ship.

[0022] The seventh invention relates to a seal structure in which the seal liner is moved to the other side when a spare oil seal is used, thereby activating the spare oil seal via the seal liner. With this seal structure, even if the sealing performance deteriorates at sea, the spare oil seal can be easily used. This makes it possible to easily restore the sealing performance at sea without having to dry-dock the ship.

[0023] The eighth invention provides a seal structure comprising a recovery unit for recovering seawater that has entered the ship through the seawater seal, and an alarm generation unit for issuing a visible and audible alarm when it detects the infiltrated seawater. According to this seal structure, the seawater seal unit When seawater enters the ship, the recovery unit can quickly retrieve it, and the alarm unit can promptly notify the ship's crew that seawater has entered the ship.

[0024] The seal structure according to the ninth invention comprises a recovery unit for recovering oil leaked into the ship from the oil seal, and an alarm generation unit for issuing a visible and audible alarm when the leaked oil is detected. According to this seal structure, the oil seal unitWhen oil leaks into the ship, the recovery unit can quickly recover the oil, and the alarm unit can promptly notify the ship's crew of the oil leak.

[0025] The ship propulsion device according to the tenth invention is equipped with any of the seal structures of the first to ninth inventions. Such a ship propulsion device can achieve the effects of each of the seal structures of the first to fourth inventions. [Brief explanation of the drawing]

[0026] [Figure 1] A cross-sectional view showing a ship's propulsion system. [Figure 2] A diagram showing a ship's propulsion system attached to the bottom of a vessel. [Figure 3] A cross-sectional view showing the sealing device of the first embodiment. [Figure 4] This is a cross-sectional view showing the sealing device of the second embodiment. The left side of the rotating shaft C shows the state where the reserve seawater seal is not operating (normal state), and the right side of the rotating shaft C shows the state where the reserve seawater seal is operating. [Figure 5] This is a cross-sectional view showing the sealing device of the third embodiment. The left side of the rotating shaft C shows the state where the reserve seawater seal is not operating (normal state), and the right side of the rotating shaft C shows the state where the reserve seawater seal is operating. [Figure 6] This is a cross-sectional view showing the sealing device of the fourth embodiment. The left side of the rotating shaft C shows the state where the reserve seawater seal is not operating (normal state), and the right side of the rotating shaft C shows the state where the reserve seawater seal is operating. [Modes for carrying out the invention]

[0027] Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the vertical direction in Figure 1 is described as the "vertical direction" of the seal structure (seal device) and the ship's propulsion system 1. Similarly, the longitudinal direction shown in Figure 1 is described as the "longitudinal direction" of the seal structure (seal device) and the ship's propulsion system 1. Furthermore, when the ship's propulsion system 1 is attached to a ship S, the forward direction is also called the "bow direction," and the aft direction is also called the "stern direction." Furthermore, in this embodiment, "inside the ship" refers to the space inside the ship that is accessible to crew members and workers.

[0028] First, the general outline of the marine propulsion system 1 will be explained using Figure 1. The marine propulsion system 1 (hereinafter also simply referred to as propulsion system 1) is applied as a thruster equipped on a ship S, as shown in Figure 2, and is attached, for example, to the bottom B of the ship S. The propulsion system 1 mainly comprises a casing 2, a base 3 for holding the casing 2 on the bottom B, a duct 4 which is a flow path formed inside the casing 2 and has a roughly U-shaped cross-section, an impeller 6 connected to an impeller shaft 5 provided on the upstream side (bow side) of the duct 4, and a steering nozzle 8 connected to a steering shaft 7 provided on the downstream side (stern side) of the duct 4. The impeller shaft 5 and the steering shaft 7 are examples of drive shafts. An intake port 9 is provided at the upstream end of the duct 4, which is roughly flush with the underside of the bottom B. At the downstream end of the duct 4, the steering nozzle 8 is rotatably positioned by the steering shaft 7. The steering nozzle 8 has a discharge port 10 that is substantially flush with the underside of the hull B. The impeller shaft 5 extends vertically and is connected to a power transmission mechanism (not shown), which is an example of a drive unit located in a housing 11 positioned on the mounting surface A inside the ship. This power transmission mechanism is connected to a drive source 100 (see Figure 2), and driving force is transmitted from the drive source 100. The ship's propulsion system 1 can be attached to any location on the hull of the ship S that is submerged in water. For example, it can be attached to the bow or stern of the hull in addition to the bottom B, and is not particularly limited to the attachment location or direction of the ship's propulsion system 1 shown in this embodiment. For example, in the longitudinal direction of the ship, the discharge port 10 (steering nozzle 8) may be placed on the front side and the intake port 9 may be placed behind the discharge port 10. Alternatively, in the lateral direction of the ship, the intake port 9 may be placed on one side and the discharge port 10 on the other side. Furthermore, when the ship's propulsion system 1 is installed on the bottom B of the ship, as shown in Figure 2, it can generate thrust stably at all times, even when the ship S is navigating at a low draft.

[0029] The housing 11 has a housing body 11a that houses the power transmission mechanism and a housing support portion 11b that protrudes downward from the lower part of the housing body 11a. The housing support portion 11b is fixed to the upper end of the casing 2 and supports the housing body 11a. The impeller shaft 5 is rotationally driven by the driving force transmitted from the drive source 100 via the power transmission mechanism. As a result, the impeller 6 is rotationally driven by the impeller shaft 5 around the rotation axis C. The steering shaft 7 extends in the vertical direction and is connected to a power transmission mechanism (not shown), which is an example of a drive unit in the housing 12 located on the mounting surface A inside the ship. This power transmission mechanism is connected to a drive source (not shown), and driving force is transmitted from the drive source. The housing 12 has a housing body 12a that houses the power transmission mechanism and a housing support portion 12b that protrudes downward from the lower part of the housing body 12a. The housing support portion 12b is fixed to the upper end of the casing 2 and supports the housing body 12a. The steering shaft 7 is rotated by the driving force transmitted from the drive source via a power transmission mechanism, allowing the steering nozzle 8 connected to the steering shaft 7 to rotate to any position within 360 degrees around the pivot axis D.

[0030] The propulsion system 1, consisting of the above configuration, draws water in from the intake port 9 as shown by the arrow in Figure 1 by the rotational drive of the impeller 6, pressurizes the water with the impeller 6, and discharges it to the outside through the duct 4 and the discharge port 10 of the steering nozzle 8. The reaction force from this water discharge generates thrust, causing the ship to move forward. Furthermore, the direction of the discharge port 10 of the steering nozzle 8 can be set to any position within a 360-degree range by appropriately controlling the rotation angle of the steering shaft 7, so the direction of the discharged water flow from the discharge port 10 can be set to any direction, and the direction of thrust can be changed as appropriate in any direction.

[0031] A sealing device 20, which is the first embodiment of the sealing structure of the present invention, is attached to the steering shaft 7. Furthermore, a sealing device 30, which is the second embodiment of the sealing structure of the present invention, is attached to the impeller shaft 5.

[0032] As shown in Figure 3, the sealing device 20 mainly comprises a seawater seal unit 21, which is an example of a seawater seal for preventing seawater from entering, and a lubricating oil seal unit 25, which is an example of a lubricating oil seal for preventing lubricating oil from leaking out of the power transmission mechanism inside the housing 12, and is positioned above the seawater seal unit 21 via a predetermined space SP. The lubricating oil seal unit 25 is positioned at approximately the same height as the mounting surface A inside the ship. In this embodiment, the steering shaft 7 extends vertically, and the positions of the seawater seal unit 21 and the lubricating oil seal unit 25 are arranged vertically. However, for example, the steering shaft 7 may extend horizontally, and the positions of the seawater seal unit 21 and the lubricating oil seal unit 25 may be arranged horizontally.

[0033] The seawater seal unit 21 includes a seawater seal holding part 22 and a seawater seal 23.

[0034] The seawater seal holding portion 22 has a substantially cylindrical cylindrical portion 22a, an annular flange-shaped mounting portion 22b extending radially outward from the upper end of the cylindrical portion 22a, an annular extension portion 22c extending radially inward from the lower end of the cylindrical portion 22a, and an annular locking member 22d that locks the uppermost ends of the multiple seawater seals 23. The locking member 22d is fixed to the upper end of the cylindrical portion 22a by a mounting member (not shown). By fixing it in this way, the multiple seawater seals 23 are stably held in the vertical direction. In this embodiment, a single seawater seal 23 is provided, but for example, a configuration in which multiple seawater seals 23 are arranged in a vertical direction may also be used.

[0035] The seawater seal 23 is an annular elastic member positioned radially inward of the cylindrical portion 22a.

[0036] The seawater seal unit 21 is housed in the space between the steering shaft 7 of the propeller 1 and the upper part of the casing 2, and its mounting portion 22b is fixed to the upper end of the casing 2 by a mounting member. As a result, the seawater seal 23 of the seawater seal unit 21 slidably contacts the outer circumferential surface of the steering shaft 7 and is sealed by the seawater seal 23.

[0037] The lubricating oil seal unit 25 is positioned above the seawater seal unit 21 via a predetermined space SP. That is, the lubricating oil seal unit 25 and the seawater seal unit 21 are positioned opposite each other via a predetermined space SP. The state within space SP can be visually observed by an operator from outside the housing 12 through an opening (not shown) provided in the housing support portion 12b of the housing 12.

[0038] The lubricating oil seal unit 25 includes a lubricating oil seal holding portion 26 and a lubricating oil seal 27.

[0039] The lubricating oil seal retaining portion 26 has a cylindrical portion 26a formed in a horizontally flattened cylindrical shape overall, an annular extension portion 26b extending radially inward from the upper end of the cylindrical portion 26a, and an annular locking member 26c that locks the lower end of the lubricating oil seal 27. The locking member 26c is fixed to the lower end of the cylindrical portion 26a by a mounting member (not shown).

[0040] The lubricating oil seal 27 is an annular elastic member positioned radially inward of the cylindrical portion 26a.

[0041] The lubricating oil seal unit 25 is fixed to the lower end of the housing body 12a by a mounting member, with its cylindrical portion 26a secured to it. As a result, the lubricating oil seal 27 of the lubricating oil seal unit 25 slidably contacts the outer circumferential surface of the steering shaft 7 and is sealed by the lubricating oil seal 27.

[0042] The sealing device 20 of the first embodiment is provided with a lubricating oil sealing unit 25 positioned above the seawater sealing unit 21 via a predetermined space SP, for preventing the leakage of lubricating oil from drive units such as the power transmission mechanism. With this sealing device 20, the lubricating oil sealing unit 25 and the seawater sealing unit 21 are separated vertically via a predetermined space SP within the ship. For example, the lubricating oil from the power transmission mechanism will only leak into the ship, preventing it from leaking out into the ocean. Furthermore, with this sealing device 20, the provision of a predetermined space SP allows workers to visually check the amount of lubricating oil leakage and seawater ingress when a malfunction occurs in the sealing device 20, and to easily monitor changes in these amounts.

[0043] As shown in Figure 1, the sealing device 20 includes a recovery unit 28 that recovers seawater that has entered the ship through the seawater seal 23, and an alarm generation unit 29 that emits a visible and audible alarm when it detects the ingress of seawater. This allows the recovery unit 28 to quickly recover seawater that has entered the ship through the seawater seal 23, and the alarm generation unit 29 to promptly notify the ship's crew that seawater has entered the ship. Furthermore, as shown in Figure 1, the sealing device 20 includes a recovery unit 28 for recovering oil leaked into the ship from the lubricating oil seal 27, and an alarm generation unit 29 that emits a visible and audible alarm when it detects leaked oil. This allows the recovery unit 28 to quickly recover oil leaked into the ship from the lubricating oil seal 27, and the alarm generation unit 29 to promptly notify the ship's crew of the oil leak. Furthermore, each of the sealing devices 30, 40, and 50 described below can also be configured to include a recovery unit 28 and an alarm generation unit 29.

[0044] As shown in Figure 4, the sealing device 30 of the second embodiment mainly comprises a seawater sealing unit 31, which is an example of a seawater seal, and a lubricating oil sealing unit 38, which is an example of a lubricating oil seal.

[0045] The seawater seal unit 31 includes a seawater seal holding part 32, a seawater seal 33, a spacer 35, a spare seawater seal holding part 36, and a spare seawater seal 37. In this embodiment, the "reserve seawater seal" refers to a spare seal that is not activated under normal circumstances (standby).

[0046] The seawater seal retaining portion 32 has a substantially cylindrical cylindrical portion 32a, an annular extension portion 32b extending radially inward from the upper end of the cylindrical portion 32a, and an annular locking member 32c that locks the lowest end of the seawater seal 33.

[0047] The seawater seal 33 is an annular elastic member positioned radially inward of the cylindrical portion 32a. In this embodiment, a single seawater seal 33 is provided, but for example, a configuration in which multiple seawater seals 33 are arranged in a vertical direction may also be used.

[0048] The spacer 35 is roughly annular in shape. The spacer 35 can be divided into multiple parts and removed from the seawater seal unit 31.

[0049] The reserve seawater seal retaining portion 36 is substantially annular and has an annular extension portion 36a that extends radially inward from the upper end.

[0050] The reserve seawater seal 37 is an annular elastic member positioned radially inward of the reserve seawater seal holding portion 36.

[0051] A spare seawater seal 37 is attached to the spare seawater seal holding section 36 radially inward. The spare seawater seal 37 is positioned on the upper part of the seawater seal unit 31 via a spacer 35 that is removable from the seawater seal unit 31. By removing the spacer 35 from the seawater seal unit 31 and moving the spare seawater seal 37 downward, the seawater seal unit 31 comes into contact with the outer circumferential surface of the impeller shaft 5, and the spare seawater seal 37 is activated. Furthermore, the spacer 35 and the reserve seawater seal retaining part 36 are fixed to the upper part of the seawater seal retaining part 32 by mounting members (not shown). The seawater seal unit 31 is housed in the upper space of the casing 2, and its cylindrical portion 32a is fixed to the lower end of the housing support portion 11b by a mounting member (not shown). As a result, the seawater seal 33 of the seawater seal unit 31 slidably contacts the outer circumferential surface of the impeller shaft 5, and is sealed by the seawater seal 33.

[0052] The lubricating oil seal unit 38 is positioned above the seawater seal unit 31 via a predetermined space SP. That is, the lubricating oil seal unit 38 and the seawater seal unit 31 are positioned opposite each other via a predetermined space SP. The state within space SP can be visually observed by an operator from outside the housing 12 through an opening 11c provided in the housing support portion 11b of the housing 11.

[0053] The lubricating oil seal unit 38 has a substantially annular lubricating oil seal holding portion 38a and a lubricating oil seal 38b, which is an annular elastic member held radially inward of the lubricating oil seal holding portion 38a.

[0054] The lubricating oil seal unit 38 is fixed to the lower end of the housing body 11a by a mounting member, with the lubricating oil seal holding portion 38a fixed to the lower end of the housing body 11a. As a result, the lubricating oil seal 38b of the lubricating oil seal unit 38 slidably contacts the outer circumferential surface of the impeller shaft 5 and is sealed by the lubricating oil seal 38b.

[0055] The sealing device 30 of the second embodiment provides the same effects as the sealing device 20 of the first embodiment. Furthermore, with the sealing device 30 of the second embodiment, even if a malfunction occurs in the seawater sealing unit 31 during use, the sealing performance can be restored in a short time by activating the spare seawater seal 37. Specifically, since the spare seawater seal holding unit 36 ​​equipped with the spare seawater seal 37 is arranged via a removable spacer 35 from the seawater sealing unit 31, when using the spare seawater seal 37, the spacer 35 is removed and the spare seawater seal holding unit 36 ​​is moved downward and fixed to the upper part of the seawater seal holding unit 32 with a mounting member, thereby enabling the spare seawater seal 37 to be activated (see the activated state of the spare seal shown in the right part of Figure 3). With this sealing device 30, even if the sealing performance deteriorates at sea, the spare seawater seal 37 can be easily used by removing the spacer 35. This makes it possible to easily restore the sealing performance at sea without having to dry-dock the ship.

[0056] Next, as a modified example of the sealing device 30 of the second embodiment, a sealing device 40 of the third embodiment will be described. In the following descriptions of each embodiment, we will mainly describe the parts that have been added or modified in each embodiment. Other identical parts, identical parts, or parts with similar functions will be denoted by the same reference numerals, and their descriptions will be omitted.

[0057] As shown in Figure 5, the sealing device 40 mainly comprises a seawater sealing unit 41, which is an example of a seawater seal, and a lubricating oil sealing unit 38, which is an example of a lubricating oil seal.

[0058] The seawater seal unit 41 includes a seawater seal holding section 42, a seawater seal 43, a spare seawater seal holding section 44, a spare seawater seal 45, a seal liner 46, and a spare seal liner 47.

[0059] The seawater seal retaining portion 42 has a substantially cylindrical cylindrical portion 42a, an annular extension portion 42b extending radially inward from the upper end of the cylindrical portion 42a, and an annular locking member 42c that locks the lower end of the spare seawater seal 45. The locking member 42c is fixed to the lower end of the cylindrical portion 42a by a mounting member (not shown).

[0060] The seawater seal 43 is an annular elastic member positioned radially inward of the cylindrical portion 42a.

[0061] The reserve seawater seal retaining portion 44 is substantially annular and has an annular extension portion 44a that extends radially inward from its upper end. The reserve seawater seal retaining portion 44 is fixed to the upper end of the cylindrical portion 42a by a mounting member (not shown).

[0062] The reserve seawater seal 45 is an annular elastic member positioned radially inward of the reserve seawater seal retaining portion 44. Under normal conditions, the reserve seawater seal 45 faces the outer circumferential surface of the impeller shaft 5 with a predetermined gap (see the reserve seawater seal 45 in normal conditions shown in Figure 5).

[0063] The seal liner 46 is a cylindrical, metal component. The seal liner 46 is positioned in contact with the outer circumferential surface of the impeller shaft 5 and is fixed on the impeller shaft 5 in a position opposite to the seawater seal 43. The spare seal liner 47 is attached to the outer circumferential surface of the impeller shaft 5 above the spare seawater seal 45. The spare seal liner 47 is a cylindrical, metal component that is in contact with the outer circumferential surface of the impeller shaft 5 and is positioned at a predetermined location above the spare seawater seal 45. The spare seal liner 47 is movable from its predetermined position to a lower position (a position where the spare seal liner 47 contacts the upper end of the seal liner 46). When using the spare seawater seal 45, the spare seal liner 47 is moved downward, causing the spare seawater seal 45 to become operational via the spare seal liner 47. The seawater seal unit 41 is housed in the upper space of the casing 2 and fixed to the lower end of the housing support portion 11b by mounting members (not shown). As a result, the seawater seal 43 of the seawater seal unit 41 slidably contacts the outer circumferential surface of the seal liner 46 fixed to the impeller shaft 5, and is sealed by the seawater seal 43.

[0064] The sealing device 40 of the third embodiment provides the same effects as the sealing device 20 of the first embodiment. Furthermore, with the sealing device 40 of the third embodiment, even if a malfunction occurs in the seawater seal 43 during use, the spare seal liner 47 is moved downward, and the spare seawater seal 45 slidably contacts the outer circumferential surface of the spare seal liner 47, thereby sealing (see the operating state of the spare seawater seal 45 shown on the right side of Figure 5). This provides the same effects as the sealing device 30 of the second embodiment. In the case of the sealing device 40 of the third embodiment, since it does not use a spacer 35 like the sealing device 30 of the second embodiment, the work of removing the spacer 35 can be omitted, and the spare seawater seal 45 can be operated in a shorter amount of time.

[0065] Next, as a modified example of the sealing device 40 of the third embodiment, a sealing device 50 of the fourth embodiment will be described.

[0066] As shown in Figure 6, the sealing device 50 mainly comprises a seawater sealing unit 51, which is an example of a seawater seal, and a lubricating oil sealing unit 38, which is an example of a lubricating oil seal.

[0067] The seawater seal unit 51 includes a seawater seal holding section 52, a seawater seal 53, a spare seawater seal holding section 54, a spare seawater seal 55, and a seal liner 56.

[0068] The seawater seal retaining portion 52 is substantially annular and has an annular extension portion 52a that extends radially inward from its upper end. The seawater seal retaining portion 52 is fixed to the upper end of the cylindrical portion 54a by a mounting member (not shown).

[0069] The reserve seawater seal retaining portion 54 has a substantially cylindrical cylindrical portion 54a, an annular extension portion 54b extending radially inward from the upper end of the cylindrical portion 54a, and an annular locking member 54c that locks the lower end of the seawater seal 53. The locking member 54c is fixed to the lower end of the cylindrical portion 54a by a mounting member (not shown).

[0070] The seawater seal 53 is an annular elastic member positioned radially inward of the seawater seal holding portion 52. The spare seawater seal 55 is an annular elastic member positioned radially inward of the cylindrical portion 54a. Under normal conditions, the spare seawater seal 55 faces the outer circumferential surface of the impeller shaft 5 with a predetermined gap (see the spare seawater seal 55 under normal conditions shown in Figure 6).

[0071] The seal liner 56 is mounted on the outer circumferential surface of the impeller shaft 5 above the reserve seawater seal 55. The seal liner 56 is an annular, metal component. The seal liner 56 is positioned in contact with the outer circumferential surface of the impeller shaft 5, and under normal circumstances, its lower portion is positioned in a predetermined location facing multiple seawater seals 53 (see Figure 6 for the seal liner 56 in its normal position). The seal liner 56 is movable from its predetermined position down to a lower position (where the lower portion of the seal liner 56 corresponds to the reserve seawater seal 55). The seal liner 56 is also movable to a position where its lower end is locked into a stepped portion 5a provided on the impeller shaft 5. When using the reserve seawater seal 55, the seal liner 56 is moved downward from its predetermined position, thereby activating the reserve seawater seal 55 via the seal liner 56. The seawater seal unit 51 is housed in the upper space of the casing 2 and fixed to the lower part of the housing support 11b by mounting members (not shown). As a result, the seawater seal 53 of the seawater seal unit 51 slidably contacts the outer circumferential surface of the seal liner 46 fixed to the impeller shaft 5, and is sealed by the seawater seal 53.

[0072] The sealing device 50 of the fourth embodiment provides the same effects as the sealing device 20 of the first embodiment. Furthermore, with the sealing device 50 of the fourth embodiment, even if a malfunction occurs in the seawater seal 53 during use, the seal liner 56 moves downward, and the spare seawater seal 55 slidably contacts the outer circumferential surface of the seal liner 56, thereby sealing (see the operating state of the spare seawater seal 55 shown on the right side of Figure 6). This provides the same effects as the sealing device 30 of the second embodiment. In the case of the sealing device 50 of the fourth embodiment, since it does not use a spacer 35 like the sealing device 30 of the second embodiment, the work of removing the spacer 35 can be omitted, and the spare seawater seal 55 can be operated in a shorter amount of time.

[0073] In the sealing devices of the first to fourth embodiments, a spare seawater seal is provided in the seawater seal unit so that the spare seawater seal can be activated if a malfunction occurs in the seawater seal being used. However, a similar configuration may be applied to the lubricating oil seal unit, providing a spare lubricating oil seal so that the spare lubricating oil seal can be activated if a malfunction occurs in the lubricating oil seal being used. Alternatively, the above-mentioned auxiliary lubricating oil seal may be positioned in a part of the lubricating oil seal unit via a removable spacer, and the auxiliary lubricating oil seal may be activated by removing the spacer and moving the auxiliary lubricating oil seal to the other side when using the auxiliary lubricating oil seal. Furthermore, one of the above-mentioned auxiliary lubricating oil seals may be provided with a cylindrical seal liner attached to the outer circumferential surface of the drive shaft, and when the auxiliary lubricating oil seal is used, the seal liner is moved to the other side, thereby enabling the auxiliary lubricating oil seal to operate via the seal liner. In this configuration, if a lubricating oil seal malfunctions, a spare lubricating oil seal can be easily used with minimal effort. This allows for easy restoration of seal performance at sea without requiring the ship to enter dry dock.

[0074] Finally, the technical concept disclosed herein can be broadly applied to all types of marine propulsion systems, such as marine propellers and impellers, that are equipped with a sealing structure for sealing the drive shaft. [Explanation of Symbols]

[0075] 1 Marine propulsion device 20 sealing device 21 Seawater sealing unit (seawater seal) 25. Lubricating oil seal unit (oil seal) SP space

Claims

1. A seal structure attached to the drive shaft of a ship's propulsion system, which is installed on a ship and obtains propulsion from the ship by drawing in water through an intake port and discharging it overboard through a winding channel, The drive shaft is provided on the upstream side of the flow path and rotates to draw water in from the suction port and generate a water flow in the flow path. The seal structure attached to the drive shaft is A seawater sealing unit to prevent seawater from entering, An oil seal unit is provided, which is positioned on one side of the seawater seal unit with a predetermined space between them, to prevent oil from leaking out of the drive shaft. Equipped with, At least the oil seal unit is located inside the ship, The aforementioned seawater seal unit is equipped with a spare seawater seal that does not normally operate. The seal structure is characterized in that the aforementioned spare seawater seal is configured to be able to be switched to an operating state by a predetermined switching operation.

2. The aforementioned spare seawater seal is positioned in part of the seawater seal unit via a spacer that is removable from the seawater seal unit. The seal structure according to claim 1, wherein when the spare seawater seal is used, the spacer is removed and the spare seawater seal is moved to the other side, thereby activating the spare seawater seal.

3. One of the spare seawater seals is equipped with a cylindrical seal liner that is attached to the outer surface of the drive shaft, The seal structure according to claim 1, wherein when the spare seawater seal is used, the seal liner is moved to the other side, thereby allowing the spare seawater seal to operate via the seal liner.

4. The seal structure according to claim 1, wherein the oil seal unit is provided with a spare oil seal that is not operated under normal circumstances.

5. The aforementioned spare oil seal is positioned in part of the oil seal unit via a spacer that is removable from the oil seal unit. The seal structure according to claim 4, wherein when the spare oil seal is used, the spacer is removed and the spare oil seal is moved to the other side, thereby activating the spare oil seal.

6. One of the spare oil seals is provided with a cylindrical seal liner that is attached to the outer circumferential surface of the drive shaft, The seal structure according to claim 4, wherein when the spare oil seal is used, the seal liner is moved to the other side, thereby allowing the spare oil seal to operate via the seal liner.

7. A recovery unit for recovering seawater that has entered the ship through the aforementioned seawater seal unit, A seal structure according to any one of claims 1 to 3, comprising: an alarm generating unit that emits a visible and audible alarm when it detects the infiltrated seawater.

8. A recovery unit for recovering oil leaked into the ship from the aforementioned oil seal unit, The seal structure according to any one of claims 1, 4 to 6, further comprising: an alarm generating unit that emits a visible and audible alarm when it detects the leaked oil.

9. A ship's propulsion system comprising the seal structure described in any one of claims 1 to 8.

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