KR20230145192A - Structure of the bow side of the stern tube and the ship - Google Patents

Abstract

The bow-side seal structure 10 of the stern tube 5, which is provided on a ship and passes the propeller shaft 1 from the engine room in the hull to the outside of the hull, includes a seal liner 11 mounted on the outer peripheral surface of the propeller shaft 1, the stern A seal casing (25) coupled to the pipe (5) and surrounding the seal liner (11), and a seal liner ( It is provided with a sealing member 27 surrounding 11). The seal liner 11 has a plurality of liner division parts that are separably connected to each other in the circumferential direction of the propeller shaft 1.

Description

Structure of the bow side of the stern tube and the ship

The present invention relates to a bow side room structure provided on the bow side of a stern tube in a ship.

On a ship, a stern pipe is provided at the point where the propeller shaft penetrates the hull. A bearing is provided within the stern tube to rotatably support the propeller shaft.

Seal structures are provided on the stern and bow sides of the stern tube, respectively. The stern side seal structure prevents the lubricating oil supplied to the stern tube bearings from leaking overboard and prevents water (sea water) from entering the ship. The structure of the bow side seal prevents the lubricating oil supplied to the bearings of the stern tube from leaking into the engine room within the ship and prevents water (sea water) from entering the engine room.

The stern side seal structure and the bow side seal structure each have a seal liner and a seal casing. The seal liner is mounted on the outer periphery of the propeller shaft so that it rotates integrally with the propeller shaft. The sill casing is coupled to the stern tube to surround the sill liner. The seal casing is provided with a sealing member to seal the gap between the seal casing and the seal liner. This yarn structure is described, for example, in Patent Document 1.

International Publication No. WO2011/004456

As a ship operates, wear occurs in the sliding portion of the seal liner with the sealing member. Separate the worn seal liner from the propeller shaft, and install a new seal liner or a machined (grinded) seal liner onto the propeller shaft.

In this way, when replacing the seal liner, etc., it is necessary to remove the seal liner from the propeller shaft. This work can be done as follows for the seal liner of the bow side seal structure.

On the bow side rather than the bow side seal structure, the bow end of the propeller shaft is connected to the intermediate shaft, so the connection between the propeller shaft and the intermediate shaft is disconnected. Thereafter, the intermediate shaft and its accompanying mechanisms are moved to the bow side or the propeller shaft is moved to the stern side, and then the seal liner is pulled out from the bow side end of the propeller shaft. In this way, moving the intermediate shaft, its auxiliary mechanisms, or the propeller shaft is a large work burden.

Therefore, the purpose of the present invention is to enable the seal liner to be separated from the propeller shaft in the bow side seal structure of the stern pipe while leaving the propeller shaft intact (without disconnecting the propeller shaft and the intermediate shaft).

In order to achieve the above-mentioned object, the bow side seal structure according to the present invention is a bow side seal structure of the stern tube provided on a ship and passing the propeller shaft from the engine room in the hull to the outside of the hull,

A seal liner mounted on the outer peripheral surface of the propeller shaft;

a seal casing coupled to the stern tube and surrounding the seal liner; and

a sealing member mounted on the seal casing and surrounding the seal liner to fill a gap between the seal casing and the seal liner;

The seal liner has a plurality of liner division parts that are separably connected to each other in a circumferential direction of the propeller shaft.

In addition, in order to achieve the above-described purpose, the ship according to the present invention,

A stern tube that passes the propeller shaft from the engine room in the hull to the outside of the hull, and

It is provided with the bow side seal structure to prevent lubricating oil supplied to the bearing provided on the inner periphery of the stern pipe from leaking into the engine room in the hull.

In the bow side seal structure according to the present invention, the seal liner has a plurality of liner division portions that are separably connected to each other in the circumferential direction. Therefore, when the seal liner is worn, the seal liner is moved to the bow side misaligned from the seal casing to disconnect the plurality of liner divisions, thereby allowing each liner division to be separated radially outward with respect to the propeller shaft. Therefore, the seal liner can be separated from the propeller shaft while leaving the propeller shaft as is.

Figure 1 shows the vicinity of the stern tube in a ship equipped with a bow side sill structure according to an embodiment of the present invention.
Figure 2 is a partially enlarged view of Figure 1 and shows the bow side seal structure according to an embodiment of the present invention.
FIG. 3A is a cross-sectional view taken along line IIIA-IIIA in FIG. 2, but shows only the seal liner.
FIG. 3B shows a state in which the first liner and second liner divisions constituting the seal liner in FIG. 3A are separated from each other.
FIG. 4A is a cross-sectional view taken along line IVA-IVA of FIG. 2, but shows only the seal liner.
FIG. 4B shows a state in which the first liner and second liner divisions constituting the seal liner in FIG. 4A are separated from each other.
FIG. 5 is a cross-sectional view taken along line VV of FIG. 2 and shows only the clamp ring.
Figure 6 shows the state in which the seal liner and clamp ring in Figure 2 are slid to the bow side.
Figure 7 shows an example of a change in the bow side seal structure.
FIG. 8 shows a state in which the inflatable seal portion in FIG. 7 is expanded.

Embodiments of the present invention will be described based on the drawings. Meanwhile, common parts in each drawing are assigned the same reference numerals, and duplicate descriptions are omitted.

Figure 1 shows the vicinity of the stern tube 5 in a ship provided with the bow side sill structure 10 according to an embodiment of the present invention. As shown in FIG. 1, the ship is equipped with a stern tube 5 at a predetermined position on the stern side, which allows the propeller shaft 1 to pass from the engine room in the ship to the outside of the ship. A propeller (3) is coupled to the propeller shaft (1) outside the hull. The propeller shaft 1 is driven to rotate by a main engine (not shown) provided in the engine room within the hull. Bearings 6 and 7 are provided on the inner periphery of the stern tube 5 to rotatably support the propeller shaft 1. Meanwhile, in Figure 1, the right side is the bow side and the left side is the stern side.

The stern tube (5) is provided with a bow-side seal structure (10) and a stern-side seal structure (20). The bow side seal structure 10 prevents the lubricating oil supplied to the bearings 6 and 7 on the bow side of the stern pipe 5 from leaking into the engine room within the hull. The stern side seal structure 20 is located on the stern side of the stern tube 5 and prevents water (sea water) from entering the stern tube 5 from outside the hull, and also prevents water supplied to the bearings 6 and 7. Prevents lubricant from leaking out of the hull.

Figure 2 is a partially enlarged view of Figure 1 and shows the bow side seal structure 10 according to an embodiment of the present invention. The bow side seal structure 10 includes a seal liner 11, a clamp ring 17, a seal casing 25, and a seal member 27.

(Composition of seal liner)

The seal liner 11 is mounted on the outer peripheral surface of the propeller shaft 1 as shown in FIG. 2. FIG. 3A is a cross-sectional view taken along line IIIA-IIIA in FIG. 2, but shows only the seal liner 11. FIG. 4A is a cross-sectional view taken along line IVA-IVA in FIG. 2, but shows only the seal liner 11. The seal liner 11 has a ring shape surrounding the central axis C (propeller shaft 1) when viewed from the direction of the central axis C of the propeller shaft 1.

The seal liner 11 has first and second liner divisions 11a and 11b. FIG. 3B shows a state in which the first liner split portion 11a and the second liner split portion 11b constituting the seal liner 11 in FIG. 3A are separated from each other. FIG. 4B shows a state in which the first liner split portion 11a and the second liner split portion 11b constituting the seal liner 11 in FIG. 4A are separated from each other. The first liner split portion 11a and the second liner split portion 11b are separably connected to each other in the circumferential direction of the central axis C of the propeller shaft 1, thereby forming the seal liner 11. . In the example of FIG. 3A, each liner split portion 11a, 11b has a length of half the circumference in the circumferential direction of the central axis C of the propeller shaft 1. Meanwhile, in the following, each “circumferential direction” means a direction around the central axis (C), and each “axial direction” means a direction parallel to the central axis (C).

2 to 4B, the first liner divided portion 11a and the second liner divided portion 11b have engaging surfaces 11a1 and 11b1, respectively. The engaging surface 11a1 of the first liner divided portion 11a and the engaging surface 11b1 of the second liner divided portion 11b are coupled to each other by contacting each other in the circumferential direction. Each engagement surface (11a1, 11b1) is a surface facing the circumferential direction. As shown in FIGS. 2 to 4B, on the mating surfaces 11a1 and 11b1 of each liner split portion 11a and 11b, the bolt hole forming portion 12 is located at two locations on the bow side (two upper and lower locations in FIG. 3A) and on the stern side. It is formed in two places (two places above and below in Figure 4a). A bolt hole is formed in the bolt hole forming portion 12. For example, the bolt hole may penetrate the bolt hole forming portion 12.

One end surface in the circumferential direction of each bolt hole forming portion 12 forms part of the corresponding engaging surfaces 11a1 and 11b1. The bolt hole is opened on one end surface in the circumferential direction. In each liner divided portion 11a, 11b, a space 13 is provided on the cross-section side outside the circumferential direction of each bolt hole forming portion 12. The space 13 is a space for arranging the bolt 15a or nut 15b. In each liner dividing portion 11a, 11b, the space 13 is formed only on a portion of the entire circumference in the circumferential direction. As shown in FIG. 3B, the space 13 may be open on the outside in the radial direction. Each of these bolt hole forming portions 12 may be formed integrally with other portions of the corresponding liner dividing portions 11a and 11b.

The first liner dividing portion 11a and the second liner dividing portion 11b are formed by aligning the respective bolt hole forming portions 12 in the circumferential direction as shown in FIGS. 3A and 4A. ) are joined by the bolt (15a) and nut (15b) inserted into the bolt hole. Accordingly, the first liner split portion 11a and the second liner split portion 11b are separably coupled to each other in the circumferential direction to form a ring-shaped seal liner 11.

Meanwhile, as shown in FIGS. 2 and 3B, a plurality of knock pins 16 may be provided on the engaging surface 11b1 to protrude from the engaging surface 11b1. When engaging the engaging surfaces 11a1 and 11b1, the plurality of knock pins 16 are respectively inserted into the plurality of pin holes formed in the engaging surface 11a, thereby positioning the engaging surfaces 11a1 and 11b1 to each other.

(Configuration of clamp ring)

The clamp ring 17 is provided to secure the seal liner 11 to the propeller shaft 1. The seal liner 11 can slide in the axial direction while the first liner split portion 11a and the second liner split portion 11b are coupled to each other in the circumferential direction and are mounted on the propeller shaft 1. The clamp ring 17 is fixed to the propeller shaft 1 by tightly tightening the propeller shaft 1. By fixing the seal liner 11 to this clamp ring 17, the seal liner 11 is fixed to the propeller shaft 1.

FIG. 5 is a cross-sectional view taken along line V-V of FIG. 2 and shows only the clamp ring 17. The clamp ring 17 is formed by coupling the first ring split portion 17a and the second ring split portion 17b to each other by a bolt 23a (and nut 23b), thereby forming the propeller shaft 1 (a cylinder to be described later). It is fastened and fixed to the outer peripheral surface of the shaped portion (1a). The seal liner 11 is fixed to the clamp ring 17 in the axial direction by a plurality of bolts 21 on the stern side of the clamp ring 17.

Bolt holes penetrate the clamp ring 17 at a plurality of locations in the circumferential direction. The bolt 21 penetrates this bolt hole in the axial direction. The tip side portions of these bolts 21 engage with a plurality of female threaded holes provided in the diameter expansion portion 14 constituting the bow side end of the seal liner 11, respectively. Accordingly, the clamp ring 17 is inserted between the heads of these bolts 21 and the diameter expansion portion 14. Accordingly, the seal liner 11 is fixed to the clamp ring 17.

Each ring split portion 17a, 17b has a length of half the circumference in the circumferential direction. Each of the first ring split portion 17a and the second ring split portion 17b has bolt hole forming portions 19 at both ends in the circumferential direction. A bolt hole penetrates each bolt hole forming portion 19. The first ring split portion 17a and the second ring split portion 17b are each bolt hole forming portion 19 in a state in which the respective bolt hole forming portions 19 are aligned in the circumferential direction as shown in FIG. 5. It is coupled by a bolt (23a) and nut (23b) inserted into the bolt hole of. On the other hand, a space 24 for arranging the bolt 23a or nut 23b is formed in each ring division portion 17a, 17b.

(Configuration of seal casing and sealing member)

The seal casing (25) is coupled to the stern tube (5) and surrounds the seal liner (11) so as to be located on the bow side of the stern tube (5).

The sealing member 27 is mounted on the inner periphery of the seal casing 25 and surrounds the seal liner 11 to fill the gap between the seal casing 25 and the seal liner 11. The sealing member 27 has a ring shape when viewed from the axial direction and has an inner peripheral surface that contacts the seal liner 11.

As shown in Figure 2, the seal casing 25 may have a plurality of casing divisions 25a, 25b, and 25c divided in the axial direction. The plurality of casing divisions 25a, 25b, and 25c may be axially coupled to each other by bolts. The sealing member 27 may be axially sandwiched between casing divisions 25a, 25b, and 25c adjacent to each other in the axial direction.

(Configuration of propeller shaft)

The propeller shaft 1 has a cylindrical portion 1a. The cross section of the cylindrical portion 1a along a plane perpendicular to the central axis C is circular with a constant radius regardless of the axial position of the cross section. The cylindrical portion 1a extends continuously in the axial direction from the stern end to the bow end. The stern side end of the cylindrical portion 1a may be, for example, a location where the propeller shaft 1 is coupled to the propeller 3. The bow side end of the cylindrical portion 1a is at a predetermined position on the bow side of the seal liner 11 (a position of engagement with the tapered portion 1b described later).

The cylindrical portion 1a has a casing opposing portion 1af and a parallel portion 1ap on the bow side of the stern tube 5. The casing opposing portion 1af is a portion opposing the seal casing 25 in the radial direction of the propeller shaft 1. The parallel portion 1ap extends from the bow side end of the casing opposing portion 1af to the bow side to the above predetermined position. The bow side edge of the parallel portion 1ap is the bow side edge of the cylindrical portion 1a.

The axial dimension of the parallel portion 1ap is larger than the axial dimension of the seal liner 11. In this case, the axial dimension of the parallel portion 1ap may be larger than the sum of the axial dimensions of the seal liner 11 and the axial dimension of the clamp ring 17.

The propeller shaft 1 has a tapered portion 1b located on the bow side of the cylindrical portion 1a. The bow side end of the cylindrical portion 1a is coupled to the stern side end of the tapered portion 1b. As the tapered portion 1b moves toward the bow, the size of its cross section (circular cross section) becomes smaller. The cylindrical portion 1a and the tapered portion 1b may be formed integrally with each other.

A flange (2) is provided at the bow side end of the tapered portion (1b). As shown in FIG. 1, the propeller shaft 1 is coaxially coupled to the intermediate shaft 9 on the bow side through the flange 2 of the tapered portion 1b. A flange (9a) is provided at the stern side end of the intermediate shaft (9). The propeller shaft 1 and the intermediate shaft 9 are coupled to each other by connecting the flanges 2 and 9a with bolts and nuts. The rotational driving force generated by the main engine (not shown) is transmitted to the propeller shaft (1) through the intermediate shaft (9).

(Seal liner removal sequence 1)

The seal liner 11 can be separated from the propeller shaft 1 in the following order (A) to (D).

(A) Release the clamp ring 17 from being fixed to the cylindrical portion 1a. That is, the force holding the propeller shaft (1) tightly by the clamp ring (17) is weakened so that the clamp ring (17) can slide on the propeller shaft (1) in the axial direction. In the example shown in Figs. 2 and 5, the bolt 23a is slightly turned so that the fastening force between the ring split portions 17a and 17b is weakened.

(B) Next, the clamp ring 17 is slid along with the seal liner 11 toward the bow side with respect to the cylindrical portion 1a. Accordingly, the seal liner 11 is moved to the parallel portion 1ap on the bow side of the seal casing 25 so as not to overlap the seal casing 25 in the radial direction. For example, the seal liner 11 is moved from the position in FIG. 2 to the position in FIG. 6. At this time, the axial dimension of the parallel portion 1ap is larger than the sum of the axial dimensions of the seal liner 11 and the axial dimension of the clamp ring 17, so that the seal liner 11 and the clamp ring 17 are It can be slid stably on the parallel part (1ap) in the shape of a circular pillar. Accordingly, damage to the seal casing 25, the clamp ring 17, and the propeller shaft 1 from colliding with each other is prevented during sliding.

(C) Next, the fixation between the seal liner 11 and the clamp ring 17 is released. For example, fixation on both sides by bolts 21 is released.

(D) After that, the clamp ring 17 is divided into a plurality of ring divisions (the first division 17a and the second ring division 17b), and each ring division is parallel to the radial outer side. In addition to separating from (1ap), the seal liner 11 is separated into a plurality of liner divisions (first liner division 11a and second liner division 11b), and each liner division is divided into diameters. Separate from the parallel part (1ap) in the direction outward.

As described above, after the seal liner 11 is separated from the propeller shaft 1 (parallel portion 1ap), a new seal liner 11 or a finished seal liner 11 is formed as described above. It is mounted and fixed on the propeller shaft (1) so that it is placed in a position surrounded by the seal casing (25) in the reverse order of (A) to (D).

(Seal liner removal sequence 2)

The seal liner 11 can also be separated from the propeller shaft 1 in the following order (a) to (d).

(a) As in (A) above, the clamp ring 17 is released from being fixed to the cylindrical portion 1a.

(b) Next, release the fixation between the seal liner 11 and the clamp ring 17 as in (C) above.

(c) After that, the clamp ring 17 is separated into a plurality of ring divisions (the first ring division portion 17a and the second ring division portion 17b), and each ring division portion is radially rotated outward. Separate from the parallel part (1ap).

(d) Next, the seal liner 11 is slid toward the bow side with respect to the cylindrical portion 1a. Accordingly, the seal liner 11 is moved to the parallel portion 1ap on the bow side of the seal casing 25 so as not to overlap the seal casing 25 in the radial direction. At this time, the axial dimension of the parallel portion 1ap is larger than the axial dimension of the seal liner 11, so that the seal liner 11 can be stably slid over the cylindrical parallel portion 1ap. Therefore, the seal casing 25 and the propeller shaft 1 are prevented from colliding with each other and being damaged during sliding.

(e) After that, the seal liner 11 is separated into a plurality of liner divisions (the first liner division 11a and the second liner division 11b), and each of the liner divisions is radially oriented outward. Separate from the parallel part (1ap).

As described above, after separating the seal liner 11 from the propeller shaft 1 (parallel portion 1ap), a new seal liner 11 or a finished seal liner 11 is formed as described above. In the opposite order to (a) to (e), it is mounted and fixed on the propeller shaft (1) so that it is placed in a position surrounded by the seal casing (25).

(Effect by embodiment)

In the bow side seal structure 10 according to the embodiment of the present invention, the seal liner 11 has a plurality of liner split portions (a first liner split portion 11a and a second liner split portion (11a) divided from each other in the circumferential direction. 11b)), and the plurality of liner divisions are connected in the circumferential direction to form the seal liner 11. Accordingly, when the seal liner 11 is worn, the seal liner 11 is moved to the bow side so as to be offset from the seal casing 25, and a plurality of liner dividing parts (the first liner dividing part 11a and the second liner dividing part) are separated from the seal casing 25. By disconnecting the installments 11b from each other, each liner segment can be separated radially outward with respect to the propeller shaft 1. Therefore, with the propeller shaft 1 intact (for example, without disconnecting the propeller shaft 1 and the intermediate shaft 9), the entire seal casing 25 is attached to the stern tube 5. In the coupled state, the seal liner 11 can be separated from the propeller shaft 1.

The present invention is not limited to the above-described embodiments, and of course various changes can be made within the scope of the technical idea of the present invention. For example, any one of the following Modification Examples 1 to 3 may be adopted alone, and two or more of the Modification Examples 1 to 3 may be adopted in arbitrary combination. In this case, points not described below are the same as described above.

(Example 1)

As described above, the seal liner 11 is divided into a first liner division 11a and a second liner division 11b in the circumferential direction, but the present invention is not limited to this. That is, the seal liner 11 has a plurality of liner division parts divided from each other in the circumferential direction, and the plurality of liner division parts are separably connected to each other in the circumferential direction, thereby forming the seal liner 11. There may be. In this case, the liner divided portions adjacent to each other in the circumferential direction may be connected by the same configuration as described above (bolt hole forming portion 12 or bolt 15a and nut 15b). That is, a bolt hole forming portion 12 or a space 13 may be formed at the circumferential end of each liner divided portion.

(Example 2)

As described above, the clamp ring 17 is divided into a first ring division portion 17a and a second ring division portion 17b in the circumferential direction, but the present invention is not limited to this. That is, the clamp ring 17 has a plurality of ring divisions divided from each other in the circumferential direction, and the plurality of ring divisions may be dividedly connected to each other in the circumferential direction to form the clamp ring 17. there is. In this case, ring divisions adjacent to each other in the circumferential direction may be connected by the same configuration as described above (bolt hole forming portion 19 or bolt 23a and nut 23b). That is, a bolt hole forming portion 19 or a space 24 may be formed at the circumferential end of each ring division portion.

(Example 3)

FIG. 7 is a diagram corresponding to FIG. 2, but shows the configuration in the case of Modification Example 3. In Modification 3, the bow side seal structure 10 is provided with an inflatable seal portion 31. The expandable seal portion 31 is mounted on the inner periphery of the seal casing 25 (casing split portion 25c in the example of Fig. 7) and surrounds the propeller shaft 1. The inflatable seal portion 31 is a ring-shaped member when viewed from the axial direction, and extends continuously in the circumferential direction to make one turn. The inflatable seal portion 31 is located more aft than the seal liner 11.

The expandable seal portion 31 has an inner space 31a that is ring-shaped when viewed from the axial direction. By supplying pressurized gas (e.g., pressurized air) to the internal space 31a, the expandable seal portion 31 expands to fill the gap between the seal casing 25 and the seal liner 11, as shown in FIG. 8. do. That is, the inner peripheral surface of the inflatable seal portion 31 is pressed against the outer peripheral surface of the propeller shaft 1.

In order to supply pressurized gas to the internal space 31a, a gas supply passage 33 (for example, a tube) is provided. The gas supply path 33 communicates with the inner space 31a of the expandable seal portion 31, and extends from the expandable seal portion 31 to the outside of the seal casing 25 (casing division portion 25c in the example of FIG. 7). is extended to

In this modification, in order to separate the seal liner 11 from the propeller shaft 1, before moving the seal liner 11 to the parallel portion 1ap on the bow side of the seal casing 25 (e.g., as described above) Before (B) above in separation sequence 1, or before (d) above in separation sequence 2), the expandable seal portion 31 is expanded. Accordingly, the gap between the seal casing 25 and the outer peripheral surface of the propeller shaft 1 is sealed by the expandable seal portion 31. Therefore, even if the seal liner 11 is separated from the propeller shaft 1, lubricating oil is prevented from leaking into the engine room from the inside of the stern tube 5.

1: Propeller shaft 1a: Cylindrical portion
1af: casing opposing portion 1ap: parallel portion
1b: Taper part 2: Flange
3: Propeller 5: Stern tube
6, 7: Bearing 9: Intermediate shaft
9a: Flange 10: Bow side seal structure
20: Stern side seal structure 11: Seal liner
11a: first liner divided portion 11b: second liner divided portion
11a1, 11b1: Mating surface 12: Bolt hole forming part
13: space 14: diameter extension
15a: bolt 15b: nut
16: Knock pin 17: Clamp ring
17a: first ring split portion 17b: second ring split portion
19: bolt hole forming part 21: bolt
23a: bolt 23b: nut
24: space 25: thread casing
25a, 25b, 25c: Casing division
27: sealing member 31: expandable seal portion
31a: internal space 33: gas supply path
C: central axis

Claims (6)

It is a structure on the bow side of the stern tube that is provided on a ship and passes the propeller shaft from the engine room in the hull to the outside of the hull,
A seal liner mounted on the outer peripheral surface of the propeller shaft;
a seal casing coupled to the stern tube and surrounding the seal liner; and
A sealing member is mounted on the seal casing and surrounds the seal liner to fill the gap between the seal casing and the seal liner,
The seal liner is a bow-side seal structure having a plurality of liner divisions that are separably connected to each other in the circumferential direction of the propeller shaft. According to paragraph 1,
Provided with the propeller shaft,
The propeller shaft has a cylindrical shape,
The cylindrical portion includes a casing opposing portion that faces the seal casing in the radial direction of the propeller shaft, and a parallel portion extending from the bow side end of the casing opposing portion to the bow side,
A bow-side seal structure in which the length of the propeller shaft in the axial direction is taken as the axial dimension, and the axial dimension of the parallel portion is larger than the axial dimension of the seal liner. According to paragraph 2,
It has a clamp ring fixed to the outer peripheral surface of the cylindrical portion at the bow side of the seal liner,
The seal liner mounted on the outer peripheral surface of the cylindrical portion is fixed to the clamp ring fixed to the cylindrical portion,
A bow side seal structure wherein the axial dimension of the parallel portion is greater than the sum of the axial dimensions of the seal liner and the axial dimension of the clamp ring. According to paragraph 2,
The propeller shaft has a tapered portion located on the bow side of the cylindrical portion,
The bow side end of the parallel portion is coupled to the stern side end of the tapered portion,
A bow-side seal structure in which the size of the cross-section becomes smaller as the tapered portion moves toward the bow side. According to any one of claims 1 to 4,
an inflatable seal mounted on the seal casing and surrounding the propeller shaft;
A bow-side seal structure in which the inflatable seal portion has an internal space, and as pressurized gas is supplied to the inner space, the inflatable seal portion expands to fill the gap between the seal casing and the seal liner. According to any one of claims 1 to 5,
A stern tube that passes the propeller shaft from the engine room in the hull to the outside of the hull; and
A ship equipped with a bow-side seal structure that prevents lubricating oil supplied to bearings provided on the inner periphery of the stern pipe from leaking into the engine room within the hull.