Fin stabilizer

Abstract

This fin stabilizer for reducing oscillations of a ship in operation comprises: a fin configured to be disposed projecting from a hull of the ship; a rigging shaft capable of pivoting the projecting fin about an axis such that the fin is accommodated in the hull; a protrusion which is fixed to the rigging shaft and which projects from the rigging shaft toward the outside in a radial direction of the rigging shaft; and a hook including a restricting portion for restricting the pivoting of the protrusion, the restricting portion having a lower strength than the rigging shaft and the protrusion.

Description

Technical Field

[0001] The present disclosure relates to a fin stabilizer for reducing a rolling of a ship in operation.

[0002] The present application claims priority based on Japanese Patent Application No. 2023-004210 filed in Japan on January 16, 2023, the contents of which are incorporated herein by reference.Background Art

[0003] A fin stabilizer generates lift by controlling an inclination of a fin projecting from a hull, and suppresses a rolling of the hull. The fin receives a load from a water flow during operation of the ship. Since the fin stabilizer restricts the movement of the fin due to a load, the fin stabilizer is configured to engage a hook lever with a retraction lever attached to a rigging shaft together with the fin (refer to PTL 1 and PTL 2).Citation ListPatent Literature

[0004] [PTL 1] Japanese Unexamined Patent Application Publication No. 2016-078477 [PTL 2] Japanese Unexamined Patent Application Publication No. 2000-043785 Summary of InventionTechnical Problem

[0005] In a case where the fin collides with marine floating objects or the like during the operation of the ship, an excessive load is applied to the rigging shaft or the retraction lever, and the rigging shaft or the retraction lever may be damaged. In order to repair the rigging shaft or the retraction lever, a large amount of repair costs may be required.

[0006] The present disclosure has been made in view of the above-described problems, and an object of the present disclosure is to provide a fin stabilizer capable of reducing repair costs.Solution to Problem

[0007] In order to achieve the above object, according to the present disclosure, there is provided a fin stabilizer for reducing a rolling of a ship in operation, the fin stabilizer including: a fin configured to be disposed projecting from a hull of the ship; a rigging shaft in which the projecting fin is capable of pivoting in an around-axis direction such that the fin is accommodated in the hull; a protrusion which is fixed to the rigging shaft and projects from the rigging shaft toward an outside in a radial direction of the rigging shaft; and a hook including a restricting portion for restricting pivoting of the protrusion, the restricting portion having a lower strength than the rigging shaft and the protrusion. Advantageous Effects of Invention

[0008] According to the fin stabilizer of the present disclosure, it is possible to reduce repair costs.Brief Description of Drawings

[0009] Fig. 1 is a perspective view schematically showing a configuration of a fin stabilizer according to one embodiment. Fig. 2 is a diagram schematically showing an attachment structure of a fin supporting shaft according to one embodiment. Fig. 3 is a perspective view showing a hook according to the embodiment. Fig. 4 is a diagram schematically showing a configuration of a restricting portion according to the embodiment. Fig. 5A is a diagram for describing operation of a restricting portion according to the embodiment. Fig. 5B is a diagram for describing the operation of the restricting portion according to the embodiment. Fig. 5C is a diagram for describing the operation of the restricting portion according to the embodiment. Fig. 6 is a perspective view showing a hook according to another embodiment. Fig. 7 is a diagram schematically showing a configuration of an upper fitting member and a configuration of a lower fitting member according to another embodiment. Fig. 8 is a diagram for describing a central region of an upper plate according to another embodiment. Fig. 9 is a diagram for describing a central region of a lower plate according to another embodiment. Fig. 10 is a diagram schematically showing a configuration of an abutting plate according to a modification example of another embodiment. Fig. 11 is a diagram schematically showing a configuration of an abutting plate according to a modification example of another embodiment. Description of Embodiments

[0010] Hereinafter, a fin stabilizer according to an embodiment of the present disclosure will be described with reference to the drawings. Such embodiments show one aspect of the present disclosure, do not limit this disclosure, and can be optionally changed within the scope of the technical concept of the present disclosure.(Configuration)

[0011] Fig. 1 is a perspective view schematically showing a configuration of a fin stabilizer 1 according to one embodiment. The fin stabilizer 1 is provided in a ship 100 and is a device for suppressing a rolling of the ship 100 in operation. As shown in Fig. 1, the fin stabilizer 1 includes a fin 2, a rigging shaft 4 (rigging shaft), a protrusion 6 (retraction lever), and a hook 8 (hook lever). In one embodiment, the fin stabilizer 1 further includes a rod 10 (rigging cylinder) and a pin 12. In Fig. 1, the ship 100 is assumed to move in the right direction on the paper surface.

[0012] The fin 2 is configured to be disposed to project from a hull 102 of the ship 100. The rigging shaft 4 is configured such that the projecting fin 2 is capable of pivoting around the axis O1 of the rigging shaft 4 so that the fin 2 is accommodated in the hull 102.

[0013] In the present disclosure, around the axis O1 of the rigging shaft 4 refers to a circumferential direction about the axis O1 of the rigging shaft 4. Hereinafter, "around the axis O1 of the rigging shaft 4" is referred to as "around-axis direction D1". A direction in which the fin 2 pivots in the around-axis direction D1 to be accommodated in the hull 102 is defined as a first side in the around-axis direction D1, and a direction opposite to the first side in the around-axis direction D1 is defined as a second side in the around-axis direction D1.

[0014] In the embodiment shown in Fig. 1, the rigging shaft 4 includes a rod-shaped main body portion 4a that pivots around an axis O1 of the rigging shaft 4, a first rotating body 4b that is fixed to the main body portion 4a to pivot together with the main body portion 4a, and a second rotating body 4c that is provided separately from the first rotating body 4b and is fixed to the main body portion 4a to pivot together with the main body portion 4a. Each of the first rotating body 4b and the second rotating body 4c covers the main body portion 4a from the outside in a radial direction of the rigging shaft 4. In some embodiments, the first rotating body 4b and the second rotating body 4c are integrally configured.

[0015] In the present disclosure, the radial direction of the rigging shaft 4 is a direction orthogonal to a direction in which the axis O1 of the rigging shaft 4 extends, and the axis O1 of the rigging shaft 4 is a starting point. In the following, the "radial direction of the rigging shaft 4" will be described as a "radial direction D2". A direction approaching the axis O1 in the radial direction D2 is defined as an inside in the radial direction D2, and a direction away from the axis O1 is defined as an outside in the radial direction D2. In one embodiment, a direction in which the axis O1 extends is along an up-down direction D3. That is, the rigging shaft 4 extends along the up-down direction D3.

[0016] In the embodiment shown in Fig. 1, the fin stabilizer 1 includes a fin supporting shaft 14 that supports the fin 2. The fin supporting shaft 14 is attached to the second rotating body 4c and connects the fin 2 and the rigging shaft 4. The fin supporting shaft 14 extends toward outside in the radial direction D2 from the second rotating body 4c. That is, the fin supporting shaft 14 pivots in the around-axis direction D1 together with the rigging shaft 4. The fin 2 can be inserted into and drawn out from the fin accommodation space 104 formed in the hull 102 by the fin supporting shaft 14 pivoting in the around-axis direction D1. In addition, the fin supporting shaft 14 supports the fin 2 such that the fin 2 is capable of pivoting (capable of swinging along the up-down direction D3) around an axis O2 of the fin supporting shaft 14. The fin stabilizer 1 generates lift by controlling the pivoting of the fin 2 with respect to a water flow from the front of the hull 102, and suppresses the rolling of the ship 100.

[0017] The attachment structure of the fin supporting shaft 14 according to the embodiment will be described. Fig. 2 is a diagram schematically showing an attachment structure of the fin supporting shaft 14 according to one embodiment. As shown in Fig. 2, a key groove 18 that is recessed toward the outside in the radial direction D2 is formed in one end surface 16 of the fin supporting shaft 14 on the rigging shaft 4 side (inside in the radial direction D2). Then, the rigging shaft 4 includes a key 20 that protrudes outward in the radial direction D2 from the second rotating body 4c and that engages with the key groove 18. In this way, in one embodiment, the fin 2 is attached to the rigging shaft 4 via the key 20 and the key groove 18. In some embodiments, a key groove 18 is formed in the second rotating body 4c, and a key 20 is provided in the fin supporting shaft 14.

[0018] The protrusion 6 is fixed to the rigging shaft 4. The protrusion 6 projects toward the outside in the radial direction D2 from the rigging shaft 4. In the embodiment shown in Fig. 1, the protrusion 6 is integrally attached to the first rotating body 4b. The protrusion 6 extends toward the outside in the radial direction D2 from the first rotating body 4b. That is, the protrusion 6 pivots in the around-axis direction D1 together with the rigging shaft 4.

[0019] The hook 8 includes a restricting portion 30 for restricting the pivoting of the protrusion 6. The strength of the restricting portion 30 is lower than that of the rigging shaft 4 and the protrusion 6. The restricting portion 30 is configured to be fractured prior to each of the rigging shaft 4 and the protrusion 6 when an impact load F toward the first side in the around-axis direction D1 is applied to the fin 2 by a predetermined or more amounts. In one embodiment, the strength of the restricting portion 30 is lower than the strength of the key 20. In one embodiment, in a case of operating the ship 100 at the maximum speed, when a load received by the fin 2 from the water flow is a design load X, the strength of the restricting portion 30 is equal to or greater than twice and equal to or less than five times the design load X. The specific configurations of the hook 8 and the restricting portion 30 will be described later.

[0020] The rod 10 has a long shape and is configured to be reciprocable along a longitudinal direction. The rod 10 is, for example, a hydraulic rigging cylinder. In one embodiment, the rod 10 extends along a front-rear direction of the hull 102. The pin 12 fastens the rod 10 and the protrusion 6. In the embodiment shown in Fig. 1, the rod 10 includes a clamping portion 24 for clamping the protrusion 6 from both sides in the up-down direction D3 on a tip side of the rod 10. The pin 12 penetrates both the protrusion 6 and the clamping portion 24. The fin stabilizer 1 according to the present disclosure controls the posture of the hull 102 by moving the fin 2 in the around-axis direction D1 by reciprocating the rod 10, so that the fin 2 can be inserted and removed or the operation of the ship 100 can be supported.

[0021] In one embodiment, the pin 12 has a lower strength than the rigging shaft 4 and the protrusion 6 and has a higher strength than the restricting portion 30. The pin 12 is configured to be fractured prior to each of the rigging shaft 4 and the protrusion 6 when an impact load F is applied to the fin 2 toward the first side in around-axis direction D1 by a predetermined or more amounts, and to be fractured after the fracture of the restricting portion 30. In one embodiment, the pin 12 has a space formed therein, and is, for example, a fuse pin.

[0022] The configuration of the hook 8 and the restricting portion 30 according to one embodiment will be described. Fig. 3 is a perspective view showing the hook 8 according to the embodiment. Fig. 4 is a diagram schematically showing a configuration of the restricting portion 30 according to the embodiment.

[0023] In one embodiment, the hook 8 is configured to move along the up-down direction D3 with respect to the restricting portion 30, and to switch whether or not to engage with the protrusion 6. In the present disclosure, the configuration of the hook 8 will be described with reference to the hook 8 (Fig. 3) in a state where the restricting portion 30 is engaged with the protrusion 6.

[0024] In the embodiment shown in Fig. 3, the hook 8 includes the main body 22 including the restricting portion 30, and the pipe portion 23 that is located outside the main body 22 in the radial direction D2 and is fixed to the main body 22. The main body 22 includes a support plate 32, an upper plate 34, and a lower plate 36. The support plate 32 extends along the up-down direction D3 (direction in which the axis O1 of the rigging shaft 4 extends). The upper plate 34 is connected to the upper end of the support plate 32 and extends from the upper end toward the second side in the around-axis direction D1. The lower plate 36 is connected to the lower end of the support plate 32 and extends from the lower end toward the second side in the around-axis direction D1. An internal space 37 defined by the support plate 32, the upper plate 34, and the lower plate 36 is formed in the main body 22.

[0025] The through-hole 25 extending along the direction orthogonal to the around-axis direction D1 and the up-down direction D3 (that is, the tangential direction D4 of the protrusion 6) is formed in the pipe portion 23. A through-shaft (not shown) supported by the hull 102 is inserted into the through-hole 25. The pipe portion 23 causes the main body 22 to pivot along the up-down direction D3 around the through-shaft by pivoting the through-shaft, and moves the restricting portion 30 along the up-down direction D3. In some embodiments, the hook 8 is configured to move along the radial direction D2 with respect to the restricting portion 30, and whether or not the hook 8 is engaged with the protrusion 6 can be switched.

[0026] The hook 8 is disposed at a limit position corresponding to a state where the fin 2 is positioned on the most second side in the around-axis direction D1. The hook 8 disposed at the limit position engages with the protrusion 6 to block the pivoting of the protrusion 6 beyond the limit position toward the first side in the around-axis direction D1. That is, the movement of the fin 2 toward the first side in the around-axis direction D1 is restricted. In one embodiment, the hook 8 is configured such that the movement of the pipe portion 23 in the around-axis direction D1 is restricted (for example, the pipe portion 23 is locked by a slip prevention means (not shown)), and the position of the main body 22 in the around-axis direction D1 is fixed.

[0027] In one embodiment, as shown in Fig. 3, the restricting portion 30 includes a support plate 32 that is fixedly disposed on a track 50 on which the protrusion 6 rotates, and a buffer material 38 that is positioned between the support plate 32 and the protrusion 6 in the around-axis direction D1 (the pivoting direction of the protrusion 6). As described above, the position of the support plate 32 of the main body 22 in the around-axis direction D1 is fixed by the pipe portion 23. The buffer material 38 is disposed in the internal space 37 of the main body 22. In this way, the restricting portion 30 is positioned between the upper plate 34 and the lower plate 36 in the up-down direction D3. That is, the upper plate 34 is positioned above the restricting portion 30, and the lower plate 36 is positioned below the restricting portion 30.

[0028] The buffer material 38 has a lower strength than the support plate 32. That is, the buffer material 38 is configured to be fractured prior to the support plate 32 when an impact load F toward the first side in the around-axis direction D1 is applied to the fin 2 by a predetermined or more amounts. In one embodiment, as shown in Fig. 4, a notch 40 is formed in one end surface 39 of the support plate 32 on the buffer material 38 side.

[0029] In one embodiment, as shown in Fig. 3, the buffer material 38 includes a cylindrical member 42 having a cylindrical shape. The cylindrical member 42 extends along the tangential direction D4 of the track 50. As shown in Fig. 4, the restricting portion 30 includes a first cylindrical member 42A (42), a second cylindrical member 42B (42) disposed closer to the support plate 32 than the first cylindrical member 42A, and an intermediate plate 44 disposed between the first cylindrical member 42A and the second cylindrical member 42B. In the embodiment shown in Fig. 3, the two first cylindrical members 42A are arranged along the up-down direction D3. However, the present disclosure is not limited to this embodiment. The restricting portion 30 includes any number of the cylindrical members 42. In the present disclosure, in order to facilitate the description of the hook 8 and the restricting portion 30, a direction toward the first side in the around-axis direction D1 of the tangential direction D4 is referred to as a first side of the tangential direction D4, and a direction opposite to the first side in the tangential direction D4 is referred to as a second side in the tangential direction D4.

[0030] In one embodiment, as shown in Fig. 4, the restricting portion 30 further includes an abutting plate 46 that is in contact with the end surface 45 of the first cylindrical member 42A on the protrusion 6 side. The abutting plate 46 has a higher strength than the first cylindrical member 42A. The abutting plate 46 is clamped between the upper plate 34 and the lower plate 36. That is, the upper plate 34 is positioned above the abutting plate 46 of the restricting portion 30, and covers the abutting plate 46 in a state of being abutted from above. Similarly, the lower plate 36 is positioned below the abutting plate 46 of the restricting portion 30, and covers the abutting plate 46 in a state of abutting the abutting plate 46 from below.(Operations and Effects)

[0031] The operation and effect of the fin stabilizer 1 according to one embodiment will be described. Figs. 5A to 5C are diagrams for describing the operation of the restricting portion 30 according to the embodiment. When marine floating object or the like collides with the fin 2 and an impact load F toward the first side in the around-axis direction D1 is applied to the fin 2 by a predetermined or more amounts, a torque T that causes the rigging shaft 4 to pivot to the first side in the around-axis direction D1 is generated. Then, as shown in Fig. 5A, the torque T is transmitted to the restricting portion 30 of the hook 8 in a state where the protrusion 6 abuts against the abutting plate 46.

[0032] According to one embodiment, since the restricting portion 30 of the hook 8 has a lower strength than the rigging shaft 4 and the protrusion 6, the restricting portion 30 can be fractured by the torque T before each of the rigging shaft 4 and the protrusion 6 is damaged. The hook 8 is easier to repair than the rigging shaft 4 or the protrusion 6. Therefore, the repair cost can be reduced.

[0033] When the strength of the restricting portion 30 is smaller than twice the design load X, the hook 8 is frequently required to be repaired, and there is a concern that the repair cost may be high. In addition, when the strength of the restricting portion 30 is greater than five times the design load X, there is a concern that the rigging shaft 4 or the protrusion 6 may be damaged first. According to one embodiment, since the strength of the restricting portion 30 is equal to or greater than twice and equal to or less than five times the design load X, the hook 8 that causes the restricting portion 30 to be preferentially fractured than the rigging shaft 4 and the protrusion 6 can be realized, and the frequency of repair of the hook 8 can be suppressed.

[0034] The key 20 is highly likely to be damaged by the torque T. Further, when the key 20 is damaged, the rigging shaft 4 may need to be replaced, and thus, the repair cost is very high. According to one embodiment, since the strength of the restricting portion 30 of the hook 8 is lower than that of the key 20, damage to the key 20 can be prevented.

[0035] According to one embodiment, as shown in Fig. 5B, in a case where the torque T is larger than the strength of the buffer material 38, the buffer material 38 can be fractured after the protrusion 6 abuts against the abutting plate 46 as shown in Fig. 5A, and the energy of the torque T (impact load F) can be absorbed by the buffer material 38. For this reason, the buffer material 38 is preferentially fractured, so that damage to each of the rigging shaft 4 and the protrusion 6 can be prevented.

[0036] According to one embodiment, the buffer material 38 has a lower strength than the support plate 32. For this reason, as shown in Fig. 5C, in a case where the torque T is larger than the strength of the support plate 32, the support plate 32 is cut out from the main body 22 after the buffer material 38 is destroyed as shown in Fig. 5B, so that damage to each of the rigging shaft 4 and the protrusion 6 can be prevented.

[0037] According to one embodiment, since the restricting portion 30 includes the abutting plate 46, the torque T can be uniformly applied to the buffer material 38. Therefore, it is possible to suppress the concentration of the torque T on a part of the buffer material 38, and it is possible to improve the energy absorption efficiency of the torque T.

[0038] According to one embodiment, since the buffer material 38 includes the cylindrical member 42, it is possible to facilitate the manufacture of the buffer material 38 that is crushed with the desired magnitude of the torque T. The present disclosure is not limited to the buffer material 38 being a cylindrical member. The buffer material 38 may have a tubular shape other than a cylindrical shape, such as a rectangular tubular shape or a hexagonal tubular shape.

[0039] The present disclosure does not limit the buffer material 38 to a tubular member. In some embodiments, the buffer material 38 is a printed article obtained by performing additive manufacturing on a powder, which is a powdery material, by a 3D printer (not shown). The 3D printer is a three-dimensional additive manufacturing machine that manufactures a three-dimensional object (buffering material 38) based on, for example, three-dimensional computer-aided design (CAD) data or three-dimensional computer graphics (CG) data. This 3D printer is configured, for example, to perform additive manufacturing by locally melting a powder with a laser, and then sintering the powder, and includes a material bucket that stores the powder, a build stage for forming a printed article, and a surplus bucket for storing surplus powder. According to such a configuration, it is possible to facilitate the manufacture of the buffer material 38 that is fractured at a desired load.

[0040] In a case where the buffer material 38 includes one cylindrical member 42, there is a concern that the buffer material 38 may buckle before being crushed by the torque T. When the cylindrical member 42 buckles, there is a concern that the energy absorption efficiency of the torque T may be reduced. According to one embodiment, since the restricting portion 30 includes the first cylindrical member 42A, the intermediate plate 44, and the second cylindrical member 42B, it is possible to suppress the occurrence of buckling of the cylindrical member 42 due to the torque T. Therefore, it is possible to suppress a reduction in the energy absorption efficiency of the torque T.

[0041] According to one embodiment, since the notch 40 is formed in the one end surface 39 of the support plate 32, the strength of the support plate 32 can be easily reduced. Therefore, it is easy to realize the support plate 32 having a lower strength than the rigging shaft 4 and the protrusion 6 and a higher strength than the buffer material 38. Further, it becomes easy to make the strength of the support plate 32 lower than the strength of the pin 12. The number, position, and depth of the notches 40 are not particularly limited, and are determined based on the strength of the support plate 32.

[0042] According to one embodiment, the pin 12 has a lower strength than the rigging shaft 4 and the protrusion 6 and has a higher strength than the restricting portion 30 (the support plate 32 and the buffer material 38). For this reason, the buffer material 38, the support plate 32, and the pin 12 are fractured in this order in three stages, so that damage to each of the rigging shaft 4 and the protrusion 6 can be prevented. The pin 12 can reduce a load by adjusting the hydraulic pressure of the rod 10 (hydraulic rigging cylinder), and is easier to repair than the rigging shaft 4 or the protrusion 6. Therefore, the repair cost can be reduced.<Another Embodiment>(Configuration)

[0043] The configuration of the hook 8 according to another embodiment will be described. Fig. 6 is a perspective view showing the hook 8 according to another embodiment. In the hook 8 according to another embodiment, the same reference numerals are assigned to the same components as those of the hook 8 according to the above-described embodiment, and detailed description thereof will be omitted.

[0044] As shown in Fig. 6, the restricting portion 30 includes an upper fitting member 60 and a lower fitting member 70. Fig. 7 is a diagram schematically showing the configuration of the upper fitting member 60 and the configuration of the lower fitting member 70 according to another embodiment, and shows a cross section of the abutting plate 46 obtained by cutting the abutting plate 46 along the thickness direction of the abutting plate 46 (the tangential direction D4 of the protrusion 6).

[0045] The upper plate 34 includes a lower surface 64 facing the internal space 37. Then, as shown in Fig. 7, the upper plate 34 is formed with an upper plate recessed portion 65 that is recessed upward from the lower surface 64. In the embodiment shown in Fig. 7, the upper plate recessed portion 65 is a hole penetrating the upper plate 34 along the up-down direction D3. In this way, the upper plate recessed portion 65 penetrates the upper plate 34, so that the upper fitting member 60 can be easily attached. The present disclosure is not limited to the case where the upper plate recessed portion 65 penetrates the upper plate 34, and the upper plate recessed portion 65 may be a groove.

[0046] The lower plate 36 includes an upper surface 74 facing the internal space 37. Then, as shown in Fig. 7, the lower plate 36 is formed with a lower plate recessed portion 75 that is recessed downward from the upper surface 74. In the embodiment shown in Fig. 7, the lower plate recessed portion 75 is a hole penetrating the lower plate 36 along the up-down direction D3. In this way, the lower plate recessed portion 75 penetrates the lower plate 36, so that the lower fitting member 70 can be easily attached. The present disclosure is not limited to the case where the lower plate recessed portion 75 penetrates the lower plate 36, and the lower plate recessed portion 75 may be a groove.

[0047] An abutting plate upper-side recessed portion 66 that is recessed downward is formed in the abutting plate 46 from the upper surface 47. An abutting plate lower-side recessed portion 76 that is recessed upward is formed in the lower surface 48 of the abutting plate. In the embodiment shown in Fig. 7, each of the abutting plate upper-side recessed portion 66 and the abutting plate lower-side recessed portion 76 is a non-penetrating groove in the abutting plate 46.

[0048] The upper fitting member 60 is fitted into an upper space 67 defined by the upper plate recessed portion 65 and the abutting plate upper-side recessed portion 66. The upper fitting member 60 has lower strength than the rigging shaft 4 and the protrusion 6, and is, for example, a fuse pin.

[0049] The lower fitting member 70 is fitted into a lower space 77 defined by the lower plate recessed portion 75 and the abutting plate lower-side recessed portion 76. The lower fitting member 70 has a lower strength than the rigging shaft 4 and the protrusion 6, and is, for example, a fuse pin.

[0050] In another embodiment, as shown in Figs. 6 and 7, the restricting portion 30 includes a plurality of upper fitting members 60 arranged at intervals along the radial direction D2, and a plurality of lower fitting members 70 arranged at intervals along the radial direction D2. However, the present disclosure is not limited to this embodiment. In some embodiments, the restricting portion 30 includes one or more upper fitting members 60 and one or more lower fitting members 70. In some embodiments, the restricting portion 30 includes only one of the upper fitting member 60 and the lower fitting member 70.

[0051] In another embodiment, as shown in Fig. 6, the main body 22 of the hook 8 includes the fracture mechanism portion 80 positioned on the pipe portion 23 side in the radial direction D2 with respect to the restricting portion 30. The fracture mechanism portion 80 is formed at a base of the main body 22 to which the pipe portion 23 is connected. The fracture mechanism portion 80 has a lower strength than the rigging shaft 4 and the protrusion 6 and has a higher strength than the restricting portion 30. The fracture mechanism portion 80 is configured to be fractured prior to each of the rigging shaft 4 and the protrusion 6 when an impact load F applied to the fin 2 toward the first side in the around-axis direction D1 by a predetermined or more amounts, and to be fractured after the fracture of the restricting portion 30.

[0052] A specific configuration example of the fracture mechanism portion 80 will be described. In another embodiment, as shown in Fig. 6, the fracture mechanism portion 80 includes an upper plate groove portion 82 formed on the upper surface 68 of the upper plate 34 and a lower plate groove portion 84 formed on the lower surface 78 of the lower plate 36. The upper plate groove portion 82 linearly extends from one end to the other end of the upper plate 34 in the tangential direction D4. The lower plate groove portion 84 linearly extends from one end to the other end of the lower plate 36 in the tangential direction D4.

[0053] In another embodiment, as shown in Fig. 6, the fracture mechanism portion 80 includes an upper plate through-hole 86 penetrating a central region R1 of the upper plate 34 along the up-down direction D3. In the embodiment shown in Fig. 6, the upper plate through-hole 86 extends from the bottom surface 83 of the upper plate groove portion 82 to the lower surface 64 of the upper plate 34.

[0054] Fig. 8 is a diagram for describing the central region R1 of the upper plate 34 according to another embodiment, in which the upper plate 34 is viewed from above. In another embodiment, as shown in Fig. 8, in a case where one end of the upper plate 34 on the first side in the tangential direction D4 is defined as a position of 0% with respect to the length of the upper plate 34 in the tangential direction D4 (the magnitude of the width of the upper plate 34), and the other end of the upper plate 34 on the second side in the tangential direction D4 is defined as a position of 100% with respect to the length of the upper plate 34 in the tangential direction D4, the central region R1 of the upper plate 34 is included in a range of 20% or more and 90% or less with respect to the length of the upper plate 34 in the tangential direction D4.

[0055] In another embodiment, the fracture mechanism portion 80 includes a lower plate through-hole 88 penetrating a central region R2 of the lower plate 36 along the up-down direction D3. The lower plate through-hole 88 extends from a top surface 85 of the lower plate groove portion 84 to the upper surface 74 of the lower plate 36.

[0056] Fig. 9 is a diagram for describing the central region R2 of the lower plate 36 according to another embodiment, and shows the lower plate 36 as viewed from below. In another embodiment, as shown in Fig. 9, in a case where one end of the lower plate 36 on the first side in the tangential direction D4 is defined as a position of 0% with respect to the length of the lower plate 36 in the tangential direction D4 (the magnitude of the width of the lower plate 36), and the other end of the lower plate 36 on the second side in the tangential direction D4 is defined as a position of 100% with respect to the length of the lower plate 36 in the tangential direction D4, the central region R2 of the lower plate 36 is included in a range of 20% or more and 90% or less with respect to the length of the lower plate 36 in the tangential direction D4.

[0057] In another embodiment, the fracture mechanism portion 80 was formed by providing the upper plate groove portion 82, the lower plate groove portion 84, the upper plate through-hole 86, and the lower plate through-hole 88 at the base of the main body 22 (changing the shape). However, the present disclosure is not limited to this embodiment. The fracture mechanism portion 80 may be formed of a material having a lower strength than the rigging shaft 4 and the protrusion 6 at the base of the main body 22.(Operations and Effects)

[0058] The operation and effect of the hook 8 according to another embodiment will be described. According to another embodiment, as described with reference to Fig. 6, the restricting portion 30 includes the upper fitting member 60 and the lower fitting member 70. Then, each of the upper fitting member 60 and the lower fitting member 70 has a lower strength than the rigging shaft 4 and the protrusion 6. For this reason, the torque T is absorbed by the upper fitting member 60 and the lower fitting member 70, and at least one of the upper fitting member 60 and the lower fitting member 70 is preferentially fractured, so that damage to each of the rigging shaft 4 and the protrusion 6 can be further prevented. At least one of the upper fitting member 60 and the lower fitting member 70 is fractured before the fracture of the buffer material 38. That is, the restricting portion 30 is configured to be fractured in three stages of at least one of the upper fitting member 60 and the lower fitting member 70, the buffer material 38, and the support plate 32.

[0059] According to another embodiment, as described with reference to Fig. 6, the hook 8 includes a fracture mechanism portion 80 formed at the base of the main body 22. Then, the fracture mechanism portion 80 has a lower strength than the rigging shaft 4 and the protrusion 6 and has a higher strength than the restricting portion 30. For this reason, when the torque T that cannot be fully absorbed by the restricting portion 30 is generated, the fracture mechanism portion 80 is preferentially fractured, thereby bringing the protrusion 6 into a state of free pivoting. That is, since the protrusion 6 does not interfere with the hook 8, it is possible to suppress damage to the peripheral members such as the rigging shaft 4 due to the interference of the protrusion 6 with the hook 8.

[0060] According to another embodiment, the upper plate groove portion 82 and the lower plate groove portion 84 are formed simply by scraping the upper surface 68 of the upper plate 34 and scraping the lower surface 78 of the lower plate 36. Therefore, the fracture mechanism portion 80 can be easily formed.

[0061] When the hook 8 restricts the pivoting of the protrusion 6, bending stress is generated in the upper plate 34 and the lower plate 36. Then, each of the central region R1 of the upper plate 34 and the central region R2 of the lower plate 36 is a portion where the bending stress is relatively low. According to another embodiment, since the fracture mechanism portion 80 includes the upper plate through-hole 86 and the lower plate through-hole 88, the fracture mechanism portion 80 having resistance against bending equal to or greater than a predetermined level can be formed.

[0062] In another embodiment, in order to further prevent damage to each of the rigging shaft 4 and the protrusion 6, the restricting portion 30 includes the upper fitting member 60 and the lower fitting member 70. However, the present disclosure is not limited to this embodiment. Figs. 10 and 11 are diagrams schematically showing configurations of an abutting plate according to modification examples of another embodiment.

[0063] In the embodiment shown in Fig. 10, the abutting plate 46 includes an upper protrusion portion 90 projecting from the upper surface 47 and is inserted into the upper plate recessed portion 65 formed in the lower surface 64 of the upper plate 34, and a lower protrusion portion 92 projecting from the lower surface 48 and is inserted into the lower plate recessed portion 75 formed in the upper surface 74 of the lower plate 36. Each of the upper protrusion portion 90 and the lower protrusion portion 92 is integrally configured with the abutting plate 46. In some embodiments, the abutting plate 46 includes one of the upper protrusion portion 90 and the lower protrusion portion 92. The upper protrusion portion 90 and the lower protrusion portion 92 have a lower strength than the rigging shaft 4 and the protrusion 6.

[0064] In the embodiment shown in Fig. 11, the abutting plate 46 includes an abutting plate upper-side recessed portion 66 formed by being recessed downward from the upper surface 47 and an abutting plate lower-side recessed portion 76 formed by being recessed upward from the lower surface 48. The upper plate 34 is provided with an upper plate protrusion portion 93 projecting from the lower surface 64. The upper plate protrusion portion 93 is inserted into the abutting plate upper-side recessed portion 66. The lower plate 36 is provided with a lower plate protrusion portion 95 projecting from the upper surface 74. The lower plate protrusion portion 95 is inserted into the abutting plate lower-side recessed portion 76. Each of the upper plate protrusion portion 93 and the lower plate protrusion portion 95 has a lower strength than the rigging shaft 4 and the protrusion 6.

[0065] For example, contents described in each of the above-described embodiments are understood as follows.

[0066] [1] A fin stabilizer (1) for reducing a rolling of a ship (100) in operation according to the present disclosure, the fin stabilizer including: a fin (2) configured to be disposed projecting from a hull (102) of the ship; a rigging shaft (4) in which the projecting fin is capable of pivoting in an around-axis direction (D1) such that the fin is accommodated in the hull; a protrusion (6) which is fixed to the rigging shaft and projects from the rigging shaft toward an outside in a radial direction (D2) of the rigging shaft; and a hook (8) including a restricting portion (30) for restricting pivoting of the protrusion, the restricting portion having a lower strength than the rigging shaft and the protrusion. According to the configuration described in [1] above, when the impact load in the around-axis direction is applied to the fin due to the collision of the marine floating object or the like with the fin, the restricting portion of the hook can be destroyed before the rigging shaft and the protrusion are damaged. The hook is easier to repair than the rigging shaft or the protrusion. Therefore, the repair cost can be reduced. [2] In some embodiments, in the configuration described in [1] above, the restricting portion includes a support plate (32) that is fixedly disposed on a track (50) on which the protrusion pivots, and a buffer material (38) that is positioned between the support plate and the protrusion in a pivoting direction of the protrusion, and the buffer material has a lower strength than the support plate. According to the configuration described in [2] above, the torque generated when the impact load in the around-axis direction is applied to the fin is absorbed by the buffer material, and the buffer material is preferentially destroyed. Therefore, it is possible to prevent damage to each of the rigging shaft and the protrusion. Further, by causing the buffer material and the support plate to be fractured in two stages in this order, it is possible to further prevent damage to each of the rigging shaft and the protrusion. [3] In some embodiments, in the configuration described in [2] above, the buffer material includes at least one tubular member (42) having a tubular shape, and the at least one tubular member extends along a tangential direction of the track along which the protrusion pivots. According to the configuration described in [3] above, it is possible to facilitate the manufacture of the buffer material that is fractured at a desired load. [4] In some embodiments, in the configuration described in [2] or [3] above, the restricting portion further includes an abutting plate (46) that abuts against an end surface (45) on a protrusion side of the at least one tubular member and that has a higher strength than the at least one tubular member. According to the configuration described in [4] above, the load can be uniformly applied to the buffer material, so that it is possible to suppress the concentration of the load on a part of the buffer material. [5] In some embodiments, in the configuration described in [3] or [4] above, the at least one tubular member includes a first tubular member (42A) and a second tubular member (42B) disposed closer to a support plate side than the first tubular member, and the restricting portion further includes an intermediate plate (44) disposed between the first tubular member and the second tubular member and having a higher strength than both the first tubular member and the second tubular member. In a case where the buffer material includes one tubular member, there is a concern that the buffer material may buckle before being fractured. According to the configuration described in [5] above, since the buffer material includes the first tubular member, the intermediate plate, and the second tubular member, it is possible to suppress the occurrence of buckling of the tubular members. [6] In some embodiments, in the configuration described in any one of [2] to [5] above, a notch (40) is formed in one end surface of the support plate on a buffer material side. According to the configuration described in [6] above, the strength of the support plate can be easily reduced. [7] In some embodiments, in the configuration described in any one of [1] to [6], the fin stabilizer further includes: a rod (10) that is extendable and contractible; and a pin (12) that fastens the rod and the protrusion, in which the pin has a lower strength than the rigging shaft and the protrusion and has higher strength than the restricting portion. According to the configuration described in [7] above, the hook restricting portion and the pin are destroyed in two stages in this order, so that damage to each of the rigging shaft and the protrusion can be further prevented. The pin is easier to repair than the rigging shaft or the protrusion. Therefore, the repair cost can be reduced. [8] In some embodiments, in the configuration described in any one of [1] to [7], the fin is attached to the rigging shaft via a key (20) and a key groove (18), and the restricting portion has a lower strength than the key. According to the configuration described in [8] above, damage to the key can be prevented. [9] In some embodiments, in the configuration described in any one of [1] to [8], when a load that the fin receives from a water flow during the operation of the ship is defined as a design load, a strength of the restricting portion is equal to or more than twice and equal to or less than five times the design load. When the strength of the restricting portion is less than twice the design load, the hook needs to be frequently repaired, and there is a concern that the repair cost may be high. In addition, when the strength of the restricting portion is greater than five times the design load, there is a concern that the rigging shaft or the protrusion may be damaged first. According to the configuration described in [9] above, when an impact load in the around-axis direction is applied to the fin, it is possible to realize a hook that is fractured prior to the rigging shaft and the protrusion, and to suppress the frequency of repair of the hook.

[10] In some embodiments, in the configuration described in [4] above, the hook includes an upper plate (34) positioned above the abutting plate and a lower plate (36) positioned below the abutting plate, and the restricting portion further includes at least one of an upper fitting member (60) fitted into a space (67) defined by an upper plate recessed portion (65) formed on a lower surface (64) of the upper plate and an abutting plate upper-side recessed portion (66) formed on an upper surface (47) of the abutting plate, and a lower fitting member (70) fitted into a space (77) defined by a lower plate recessed portion (75) formed on an upper surface (74) of the lower plate and an abutting plate lower-side recessed portion (76) formed on a lower surface (48) of the abutting plate. According to the configuration described in

[10] above, the torque generated when the impact load in the around-axis direction is applied to the fin is absorbed by at least one of the upper fitting member and the lower fitting member, and at least one of the upper fitting member and the lower fitting member is preferentially fractured. Therefore, it is possible to prevent damage to each of the rigging shaft and the protrusion.

[11] In some embodiments, in the configuration described in [4] above, the hook includes an upper plate (34) positioned above the abutting plate and a lower plate (36) positioned below the abutting plate, and the abutting plate further includes at least one of an upper protrusion portion (90) that projects from an upper surface (47) of the abutting plate and is inserted into an upper plate recessed portion (65) formed on a lower surface (64) of the upper plate, and a lower protrusion portion (92) that projects from a lower surface (48) of the abutting plate and is inserted into a lower plate recessed portion (75) formed on an upper surface (74) of the lower plate. According to the configuration of

[11] above, the torque generated when the impact load in the around-axis direction is applied to the fin is absorbed by at least one of the upper protrusion and the lower protrusion, and at least one of the upper protrusion portion and the lower protrusion portion is preferentially fractured. Therefore it is possible to prevent damage to each of the rigging shaft and the protrusion.

[12] In some embodiments, in the configuration described in [4], the hook includes an upper plate (34) positioned above the abutting plate and a lower plate (36) positioned below the abutting plate, the abutting plate further includes at least one of an abutting plate upper-side recessed portion (66) formed on an upper surface (47) and into which an upper plate protrusion portion (93) projecting from a lower surface (64) of the upper plate is inserted, and an abutting plate lower-side recessed portion (76) formed on a lower surface (48) and into which a lower plate protrusion portion (95) projecting from an upper surface (74) of the lower plate is inserted, and each of the upper plate protrusion portion and the lower plate protrusion portion has a lower strength than the rigging shaft and the protrusion. According to the configuration described in

[12] above, the torque generated when the impact load in the around-axis direction is applied to the fin is absorbed by at least one of the upper plate protrusion portion and the lower plate protrusion portion, and at least one of the upper plate protrusion portion and the lower plate protrusion portion is preferentially fractured. Therefore, it is possible to prevent damage to each of the rigging shaft and the protrusion.

[13] In some embodiments, in the configuration described in any one of [1] to

[12] , the hook includes a main body (22) including the restricting portion, and a pipe portion (23) that is positioned on an outside in the radial direction than the main body and is fixed to the main body, and the main body includes a fracture mechanism portion (80) that is positioned on a pipe portion side in the radial direction than the restricting portion and has a lower strength than the rigging shaft and the protrusion and a higher strength than the restricting portion. According to the configuration described in

[13] above, when the impact load in the around-axis direction is applied to the fin, the fracture mechanism portion is preferentially fractured, thereby bringing the protrusion into a state of free pivoting. That is, since the protrusion does not interfere with the hook, it is possible to suppress damage to peripheral members such as the rigging shaft due to interference of the protrusion with the hook.

[14] In some embodiments, in the configuration described in

[13] above, the main body includes an upper plate (34) positioned above the restricting portion and a lower plate (36) positioned below the restricting portion, and the fracture mechanism portion includes at least one of an upper plate groove portion (82) formed on an upper surface (68) of the upper plate, and a lower plate groove portion (84) formed on a lower surface (78) of the lower plate. According to the configuration of

[14] above, the fracture mechanism portion can be easily formed.

[15] In some embodiments, in the configuration described in

[13] or

[14] above, the main body includes an upper plate (34) positioned above the restricting portion and a lower plate (36) positioned below the restricting portion, and the fracture mechanism portion includes at least one of an upper plate through-hole (86) penetrating a central region (R1) of the upper plate along an up-down direction (D3), and a lower plate through-hole (88) penetrating a central region (R2) of the lower plate along the up-down direction (D3).

[0067] When the hook restricts the pivoting of the protrusion, bending stress is generated in the upper plate and the lower plate. Each of the central region of the upper plate and the central region of the lower plate is a portion where the bending stress is relatively low. According to the configuration described in

[15] above, since the fracture mechanism portion includes at least one of the upper plate through-hole and the lower plate through-hole, the fracture mechanism portion having a resistance equal to or greater than a certain value against bending can be formed.Reference Signs List

[0068] 1 fin stabilizer 2: fin 4: rigging shaft 4a: main body portion 4b: first rotating body 4c: second rotating body 6: protrusion 8: hook 10: rod 14: fin supporting shaft 16: one end surface of fin supporting shaft 18: key groove 20: key 22: main body 23: pipe portion 24: clamping portion 25: through-hole 30: restricting portion 32: support plate 34: upper plate 36: lower plate 37: internal space 38: buffer material 39: one end surface of support plate 40: notch 42: cylindrical member 42A: first cylindrical member 42B: second cylindrical member 44: intermediate plate 45: end surface of first cylindrical member 46: abutting plate 47: upper surface of abutting plate 48: lower surface of abutting plate 50: track 60: upper fitting member 64: lower surface of upper plate 65: upper plate recessed portion 66: abutting plate upper-side recessed portion 67: upper space 68: upper surface of upper plate 70: lower fitting member 74: upper surface of lower plate 75: lower plate recessed portion 76: abutting plate lower-side recessed portion 77: lower space 78: lower surface of lower plate 80: fracture mechanism portion 82: upper plate groove portion 83: bottom surface of upper plate groove portion 84: lower plate groove portion 85: top surface of lower plate groove portion 86: upper plate through-hole 88: lower plate through-hole 90: upper protrusion portion 92: lower protrusion portion 93: upper plate protrusion portion 95: lower plate protrusion portion 100: ship 102: hull 104: fin accommodation space D1: around-axis direction D2: radial direction D3: up-down direction D4: tangential direction F: impact load O1: axis of rigging shaft O2: axis of fin supporting shaft R1: central region of upper plate R2: central region of lower plate T: torque

Claims

1. A fin stabilizer for reducing a rolling of a ship in operation, the fin stabilizer comprising: a fin configured to be disposed projecting from a hull of the ship; a rigging shaft in which the projecting fin is capable of pivoting in an around-axis direction such that the fin is accommodated in the hull; a protrusion which is fixed to the rigging shaft and projects from the rigging shaft toward an outside in a radial direction of the rigging shaft; and a hook including a restricting portion for restricting pivoting of the protrusion, the restricting portion having a lower strength than the rigging shaft and the protrusion.

2. The fin stabilizer according to Claim 1, wherein the restricting portion includes a support plate that is fixedly disposed on a track on which the protrusion pivots, and a buffer material that is positioned between the support plate and the protrusion in a pivoting direction of the protrusion, and the buffer material has a lower strength than the support plate.

3. The fin stabilizer according to Claim 2, wherein the buffer material includes at least one tubular member having a tubular shape, and the at least one tubular member extends along a tangential direction of the track along which the protrusion pivots.

4. The fin stabilizer according to Claim 2 or 3, wherein the restricting portion further includes an abutting plate that abuts against an end surface on a protrusion side of the at least one tubular member and that has a higher strength than the at least one tubular member.

5. The fin stabilizer according to Claim 3, wherein the at least one tubular member includes a first tubular member and a second tubular member disposed closer to a support plate side than the first tubular member, and the restricting portion further includes an intermediate plate disposed between the first tubular member and the second tubular member and having a higher strength than both the first tubular member and the second tubular member.

6. The fin stabilizer according to Claim 2 or 3, wherein a notch is formed in one end surface of the support plate on a buffer material side.

7. The fin stabilizer according to any one of Claims 1 to 3, further comprising: a rod that is extendable and contractible; and a pin that fastens the rod and the protrusion, wherein the pin has a lower strength than the rigging shaft and the protrusion and has higher strength than the restricting portion.

8. The fin stabilizer according to any one of Claims 1 to 3, wherein the fin is attached to the rigging shaft via a key and a key groove, and the restricting portion has a lower strength than the key.

9. The fin stabilizer according to any one of Claims 1 to 3, wherein when a load that the fin receives from a water flow during the operation of the ship is defined as a design load, a strength of the restricting portion is equal to or more than twice and equal to or less than five times the design load.

10. The fin stabilizer according to Claim 4, wherein the hook includes an upper plate positioned above the abutting plate and a lower plate positioned below the abutting plate, and the restricting portion further includes at least one of an upper fitting member fitted into a space defined by an upper plate recessed portion formed on a lower surface of the upper plate and an abutting plate upper-side recessed portion formed on an upper surface of the abutting plate, and a lower fitting member fitted into a space defined by a lower plate recessed portion formed on an upper surface of the lower plate and an abutting plate lower-side recessed portion formed on a lower surface of the abutting plate.

11. The fin stabilizer according to Claim 4, wherein the hook includes an upper plate positioned above the abutting plate and a lower plate positioned below the abutting plate, and the abutting plate further includes at least one of an upper protrusion portion that projects from an upper surface of the abutting plate and is inserted into an upper plate recessed portion formed on a lower surface of the upper plate, and a lower protrusion portion that projects from a lower surface of the abutting plate and is inserted into a lower plate recessed portion formed on an upper surface of the lower plate.

12. The fin stabilizer according to Claim 4, wherein the hook includes an upper plate positioned above the abutting plate and a lower plate positioned below the abutting plate, the abutting plate further includes at least one of an abutting plate upper-side recessed portion formed on an upper surface and into which an upper plate protrusion portion projecting from a lower surface of the upper plate is inserted, and an abutting plate lower-side recessed portion formed on a lower surface and into which a lower plate protrusion portion projecting from an upper surface of the lower plate is inserted, and each of the upper plate protrusion portion and the lower plate protrusion portion has a lower strength than the rigging shaft and the protrusion.

13. The fin stabilizer according to any one of Claims 1 to 3, wherein the hook includes a main body including the restricting portion, and a pipe portion that is positioned on an outside in the radial direction than the main body and is fixed to the main body, and the main body includes a fracture mechanism portion that is positioned on a pipe portion side in the radial direction than the restricting portion and has a lower strength than the rigging shaft and the protrusion and a higher strength than the restricting portion.

14. The fin stabilizer according to Claim 13, wherein the main body includes an upper plate positioned above the restricting portion and a lower plate positioned below the restricting portion, and the fracture mechanism portion includes at least one of an upper plate groove portion formed on an upper surface of the upper plate, and a lower plate groove portion formed on a lower surface of the lower plate.

15. The fin stabilizer according to Claim 13, wherein the main body includes an upper plate positioned above the restricting portion and a lower plate positioned below the restricting portion, and the fracture mechanism portion includes at least one of an upper plate through-hole penetrating a central region of the upper plate along an up-down direction, and a lower plate through-hole penetrating a central region of the lower plate along the up-down direction.

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