阅读说明：本技术 船舶 (ship with a detachable cover ) 是由 户田哲哉 安藤聪 西乡康平 于 2017-08-25 设计创作，主要内容包括：货油舱的侧壁(40)具有侧板单元(50),所述侧板单元(50)具有：顶板部(60)；底板部(70),配置在该顶板部(60)的下方；及弯曲部件(80),在所述顶板部(60)与所述底板部(70)之间沿船首尾方向延伸,并且在与延伸方向正交的剖视观察下呈向所述货油舱的外侧突出的圆弧状,以沿该圆弧状的切线方向延伸的方式分别连接有所述顶板部(60)及所述底板部(70),所述弯曲部件(80)具有随着朝向所述侧板单元(50)的所述船首尾方向的端部侧,所述圆弧状的曲率半径逐渐变大,并且遍及所述顶板部(60)与所述底板部(70)的宽度尺寸逐渐变大的扩径部(82)。(The side wall (40) of the cargo tank has a side panel unit (50), the side panel unit (50) having: a top plate (60); a bottom plate (70) disposed below the top plate (60); and a curved member (80) that extends in the fore-and-aft direction between the top plate (60) and the bottom plate (70), and that has an arc shape protruding outward of the cargo tank in a cross-sectional view orthogonal to the direction of extension, and that connects the top plate (60) and the bottom plate (70) to each other so as to extend in the tangential direction of the arc shape, wherein the curved member (80) has a diameter-enlarged portion (82) that has a radius of curvature that gradually increases toward the end of the side panel unit (50) in the fore-and-aft direction, and that gradually increases in width dimension across the top plate (60) and the bottom plate (70).)

1. A ship is provided with:

A hull having a cargo compartment divided by a side shell; and

An oil cargo tank which is housed in the cargo tank, has a side wall facing the side outer panel, and has a housing space formed therein for housing cargo,

The side wall has a side panel unit having: a top plate portion; a bottom plate portion disposed below the top plate portion; and a curved member extending between the top plate and the bottom plate in a fore-and-aft direction and having an arc shape protruding outward of the cargo tank in a cross-sectional view orthogonal to the extending direction, the top plate and the bottom plate being connected to each other so as to extend in a tangential direction of the arc shape,

The curved member has a diameter-enlarged portion in which the radius of curvature of the arc shape gradually increases toward the end portion side of the side panel unit in the fore-and-aft direction and the width dimension of the arc shape gradually increases across the top plate portion and the bottom plate portion.

2. The vessel according to claim 1, wherein,

the curved member has a constant diameter portion that is connected to the enlarged diameter portion so as to extend continuously from the enlarged diameter portion to a side opposite to the end portion side, and the arcuate curvature radius and the width dimension extend with constant dimensions.

3. The vessel according to claim 1 or 2,

The side plate unit is provided with a pair of,

In these side plate units, the end portions are joined to each other so as to protrude outward of the cargo tank, and so as to connect the top plate portions to each other, the bottom plate portions to each other, and the enlarged diameter portions of the curved members to each other.

4. The vessel according to any one of claims 1 to 3,

in the side wall, a portion of the side plate unit at the end of the side plate unit in the curved member is closest to the side outer plate.

5. The vessel according to any one of claims 1 to 4,

The curved member has linear portions extending from both ends of the arc shape in a tangential direction of the both ends,

The top plate portion and the bottom plate portion are connected to the bending member via the linear portion, respectively.

Technical Field

The present invention relates to a ship.

The present application claims priority based on japanese patent application No. 2017-081356, applied on day 17, 4/2017, and the contents thereof are incorporated herein by reference.

Background

As a ship, a transport ship in which a plurality of cargo tanks for storing liquefied gas such as LNG or LPG are arranged in the fore-aft direction is known (for example, see patent document 1). In the cargo tank, a so-called square tank is configured by joining plate members to each other in the vertical direction, the fore-aft direction, and the width direction. The cargo tank is disposed in a cargo tank partitioned by a side shell and a bulkhead of the hull. The side wall of the cargo tank faces the inner surface of the side outer panel.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-079704

Disclosure of Invention

Technical problem to be solved by the invention

However, in the transport ship, it is required to ensure that the distance between the side wall of the cargo tank and the side shell of the hull is a predetermined value or more according to the regulations. Therefore, when the shape of the side wall of the cargo tank does not partially satisfy the above-described rule, the shape of the entire tank needs to be reviewed. In particular, when the plate members are connected to each other by a connecting member bent in an arc shape, the bent portion protrudes outward of the cabin. Therefore, a distance to the side shell as regular may not be ensured.

On the other hand, in order to load more cargo such as liquefied gas into the cargo tank, it is desirable to secure a volume as much as possible. However, if the distance between the side wall of the cargo tank and the side outer panel of the hull is secured according to the above-described rule, the volume of the cargo tank may be reduced.

The invention provides a ship capable of ensuring the volume of a cargo oil tank while satisfying the requirement value of the distance between the side wall of the cargo oil tank and a side shell of a ship body.

Means for solving the technical problem

A ship according to an aspect of the present invention includes: a hull having a cargo compartment divided by a side shell; and an oil cargo tank which is housed in the cargo tank, has a side wall facing the side outer plate, and has a housing space formed therein for housing cargo, the side wall having a side plate unit, the side plate unit having: a top plate portion; a bottom plate portion disposed below the top plate portion; and a curved member extending in a fore-and-aft direction between the top plate portion and the bottom plate portion, and having an arc shape protruding outward of the cargo tank in a cross-sectional view orthogonal to the extending direction, the top plate portion and the bottom plate portion being connected to each other so as to extend in a tangential direction of the arc shape, the curved member having a diameter-enlarged portion in which a curvature radius of the arc shape gradually increases toward an end portion side of the side panel unit in the fore-and-aft direction, and a width dimension of the arc shape gradually increases over the top plate portion and the bottom plate portion.

According to the above aspect, the radius of curvature of the curved member in the end portion of the side panel unit becomes larger as it approaches the end portion. Therefore, the amount of protrusion of the bending member in the connecting portion between the top plate portion and the bottom plate portion in the end portion can be suppressed. Therefore, even when the connection portion at the end of the side panel unit is close to the side shell, the distance between the connection portion and the side shell can be secured.

Here, if the radius of curvature of the arc shape of the curved member is constant over the entire extension direction region of the curved member, the amount of projection of the curved member in the end portion of the side panel unit is large. Therefore, in order to secure a distance from the side shell, redesign is required so that each side plate unit is retracted toward the inside of the cargo tank. In this case, the top plate and the bottom plate that partition the storage space are positioned inside the cargo tank, and therefore the volume of the cargo tank is reduced.

In this aspect, the protruding amount of the curved member at the end of the side panel unit can be suppressed while maintaining the positions of the top panel portion and the bottom panel portion. Therefore, the distance from the side outer panel can be secured to a large extent while the volume of the cargo tank is secured.

In the above aspect, the bending member has a constant diameter portion that is connected to the enlarged diameter portion so as to extend continuously from the enlarged diameter portion to a side opposite to the end portion side, and the arcuate curvature radius and the width dimension extend with constant dimensions.

When the enlarged diameter portion is provided beyond the necessary portion, the volume of the cargo tank is eroded by the amount of increase in the arc-shaped large diameter portion of the curved member. In contrast, a portion of the bending member, which can secure a distance from the inboard side outer panel, is a fixed diameter portion that extends continuously with a constant radius of curvature and width dimension on the small diameter side of the enlarged diameter portion. This can prevent the cargo tank from inadvertently reducing in volume.

in the above aspect, the side plate units may be provided in a pair, and the end portions of the side plate units may be joined to each other so as to protrude outward of the cargo tank, and so as to connect the top plate portions to each other, the bottom plate portions to each other, and the enlarged diameter portions of the bending members to each other.

When the pair of side plate units are joined as described above, the portion where the pair of top plate portions and the pair of bottom plate portions are gathered is closest to the side outer panel. In this aspect, since the portion is formed by the enlarged diameter portion, the amount of projection to the side shell can be suppressed. This ensures that the distance between the side wall and the side outer plate is constant or longer, and the volume of the cargo tank can be maintained large.

In the above aspect, it is preferable that a portion of the side wall corresponding to an end of the side panel unit in the curved member be closest to the side outer panel.

Thus, the capacity of the cargo tank can be maintained to a large extent in a range in which the distance between the side wall and the side outer panel can be maintained at a predetermined value or more.

In the above aspect, the curved member may have linear portions extending from both ends of the arc shape in a tangential direction of the both ends, and the top plate portion and the bottom plate portion may be connected to the curved member via the linear portions, respectively.

Effects of the invention

According to the ship of the present invention, the volume of the cargo tank can be ensured while satisfying the required value of the distance between the side wall of the cargo tank and the side shell of the hull.

Drawings

Fig. 1 is a side view of a ship according to an embodiment.

Fig. 2 is a perspective view of a cargo tank of the ship according to the embodiment.

Fig. 3 is a schematic side view of a cargo tank side wall of the ship according to the embodiment.

Fig. 4 is a sectional view a-a of fig. 3.

Fig. 5 is a sectional view B-B of fig. 3.

Fig. 6 is a sectional view B-B of fig. 3, and is a view illustrating the operation and effect of the embodiment.

Fig. 7 is a diagram illustrating a comparative example.

Detailed Description

Hereinafter, a ship 100 according to a first embodiment of the present invention will be described in detail with reference to the drawings. The ship 100 of the present embodiment is a liquefied gas carrier ship for carrying Liquefied Petroleum Gas (LPG) as liquefied gas.

As shown in fig. 1, a ship 100 includes a hull 10, a bridge 20, a main engine 25, and a cargo tank 30A.

the hull 10 has sides 11, a bottom 12 and an upper deck 13. The side 11 is constituted by a pair of side outer plates 11a constituting the port and starboard sides 11, respectively. The bottom 12 is formed of a bottom outer plate that connects the port and starboard sides 11 at the lower part. The upper deck 13 connects the pair of left and right sides 11 above the bottom 12. The upper deck 13 is a freeboard deck as a full-through deck extending from the bow to the stern. The upper deck 13 extends in a horizontal direction.

The hull 10 is formed in a substantially box shape having a space formed therein in a cross-sectional shape perpendicular to the fore-and-aft direction by the sides 11, the bottom 12, and the upper deck 13. The stern-side portion of the hull 10 is a nacelle 14. A portion of the hull 10 on the bow side of the nacelle 14 is defined as a cargo hold 15 partitioned from the nacelle 14 by a bulkhead. The cargo hold 15 is divided into two sides in the width direction by the port and starboard side outer panels 11 a.

The bridge 20 is provided to extend upward from an upper portion of the hull 10. The bridge 20 is provided on the stern side in the upper part of the hull 10 and above the nacelle 14. The bridge 20 is formed with a plurality of layers. A control cabin 21 for controlling the ship 100 is provided in an upper layer of the bridge 20. The control room 21 is configured to be able to look out from a high place in front of the ship 100.

the main machine 25 is disposed in the nacelle 14 inside the hull 10. The main engine 25 of the present embodiment is driven by using LPG supplied from a fuel tank, not shown, as fuel. Here, the fuel of the main engine 25 is not limited to LPG, and may be a combination (bifuel) or a mixture (Dual fuel) of LPG and another fuel. The propeller 26 provided below the stern of the hull 10 is rotated by the driving of the main unit 25.

The cargo tanks 30(30A, 30B, and 30C) are provided in the cargo hold 15 of the hull 10 so that a plurality of cargo tanks (3 cargo tanks in the present embodiment) are arranged in the fore-aft direction. The portions between the adjacent cargo tanks 30 are provided with partition walls that partition the compartments in which the respective cargo tanks 30 are housed.

The cargo tank 30 of the present embodiment is a square tank configured by joining flat plate members. The cargo tank is provided with a storage space for storing LPG, which is liquefied gas as cargo.

Here, the cargo tank 30A on the most bow side among the plurality of cargo tanks 30 will be described in further detail with reference to fig. 2. The cargo hold 15 has a dimension in the width direction of the hull 10 that decreases toward the bow side as the dimension is closer to the bow side. Therefore, the cargo tank 30A on the bow-most side has a tapered shape with a smaller dimension in the width direction toward the bow side.

The cargo tank 30A on the bow-most side has an upper wall 31, a bottom wall 33, an end wall 35 and side walls 40. A storage space is formed inside the cargo tank 30A by the ceiling, the floor, the pair of end walls 35, and the pair of side walls 40. The volume of the storage space of the cargo tank 30A is determined by the arrangement of the upper wall 31, the bottom wall 33, the pair of end walls 35, and the pair of side walls 40. Further, a heat insulating material, not shown, is provided on the surfaces of the upper wall 31, the bottom wall 33, the end wall 35, and the side wall 40.

The upper wall 31 forms an upper portion of the cargo tank 30A. The upper wall 31 extends in the fore-aft direction and the width direction, i.e., in the horizontal direction. A trunk top (not shown in fig. 2) is integrally provided in the upper wall 31. The bottom wall 33 forms the bottom of the cargo tank 30A. The bottom wall 33 extends in the fore-aft direction and the width direction of the ship, i.e., in the horizontal direction, in parallel with the upper wall 31. The bottom wall 33 has a dimension in the ship width direction smaller than that of the upper wall 31.

these upper wall 31 and bottom wall 33 are formed by joining a plurality of plate members 32, 34 having a flat plate shape in the fore-and-aft direction.

The end wall 35 forms the bow-to-stern direction end of the cargo tank 30A. The end walls 35 are provided on the stern side and the bow side, respectively, and extend in the vertical direction and the width direction. That is, the end wall 35 is provided on a vertical plane orthogonal to the fore-and-aft direction of the ship. The end wall 35 connects the upper and lower upper walls 31 and the bottom wall 33. The end wall 35 on the bow side is smaller in the width direction at the lower portion than at the upper portion.

And, the side wall 40 forms a side of the cargo tank 30A. The side walls 40 extend in such a manner as to connect the upper and lower upper walls 31 and the bottom wall 33, and to connect the pair of end walls 35 in the fore-and-aft direction. That is, the side walls 40 extend in the up-down direction and the fore-aft direction. The side wall 40 faces the port-side and starboard-side outer panels 11a that divide the cargo tank 30A in the ship width direction.

The side wall 40 has a plurality of side panel units 50 aligned in the fore-aft direction. The side wall 40 is formed by joining a plurality of side plate units 50 to each other in the fore-and-aft direction.

as shown in fig. 3, each side plate unit 50 includes a top plate portion 60, a bottom plate portion 70, and a bending member 80.

The top plate portion 60 is a flat plate-like member, and forms an upper portion of the side plate unit 50.

The bottom plate portion 70 is a flat plate-like member like the top plate portion 60, and forms a lower portion of the side plate unit 50.

As shown in fig. 4 and 5, the top plate portion 60 and the bottom plate portion 70 are disposed in a posture of facing the outside of the cargo tank 30A as they approach each other in a cross-sectional view orthogonal to the fore-and-aft direction so that the side plate unit 50 projects to the outside of the cargo tank 30A. The lower end 61 of the top plate portion 60 and the upper end 71 of the bottom plate portion 70 are disposed at a vertical interval from each other in a cross-sectional view orthogonal to the fore-aft direction. The imaginary extension line of the top plate portion 60 and the imaginary extension line of the bottom plate portion 70 in the cross-sectional view intersect each other on the outboard side of the cargo tank 30A, i.e., on the side of the side shell 11a, with respect to the arrangement positions of the top plate portion 60 and the bottom plate portion 70.

The curved member 80 extends in the fore-aft direction between the lower end 61 of the top plate portion 60 and the upper end 71 of the bottom plate portion 70. The curved member 80 connects the lower end 61 of the top plate portion 60 and the upper end 71 of the bottom plate portion 70 in the fore-aft direction. The bending member 80 is joined to the top plate 60 and the bottom plate 70 by welding. The curved member 80 has an arc shape protruding outward of the cargo tank 30A when viewed in a cross section orthogonal to the extending direction of the curved member 80. That is, the curved member 80 is formed along an arc that is convex toward the outside of the cargo tank 30A in this cross-sectional view.

The curvature radius R of the curved member 80, which is circular in arc shape in cross-sectional view, is set constant at each position in the extending direction of the curved member 80. The bending member 80 is connected to the top plate portion 60 and the bottom plate portion 70 so that the top plate portion 60 and the bottom plate portion 70 extend in an arc-shaped tangential direction of the bending member 80, as viewed in a cross section orthogonal to the extending direction. Therefore, the bending member 80 is smoothly and continuously connected to the top plate portion 60 and the bottom plate portion 70 in the cross-sectional view.

As shown in fig. 3, the bending member 80 is configured by continuously connecting a fixed diameter portion 81 and an enlarged diameter portion 82 in the extending direction of the bending member 80. The constant diameter portion 81 continuously connects the top plate portion 60 and the bottom plate portion 70 in a region other than the region near the end portion of the side plate unit 50 in the bow-aft direction. The enlarged diameter portion 82 continuously connects the top plate portion 60 and the bottom plate portion 70 in a region near the end portion of the side plate unit 50 in the bow-to-stern direction.

As shown in fig. 3 and 4, the constant diameter portion 81 has a curvature radius R that is circular-arc-shaped when viewed in cross section orthogonal to the extending direction of the bending member 80 and is constant over the entire extending direction region. The constant diameter portion 81 is set to be constant over the entire extension direction region, as the width dimension (the dimension corresponding to the distance between the lower end 61 of the top plate portion 60 and the upper end 71 of the bottom plate portion 70 facing each other) which is the dimension of the top plate portion 60 and the bottom plate portion 70.

The lower end 61 of the top plate 60 connected to the fixed-diameter portion 81 and the upper end 71 of the bottom plate 70 extend parallel to each other. Parallel portions 62 and 72 are portions of the lower end 61 of the top plate portion 60 and the upper end 71 of the bottom plate portion 70, which extend parallel to each other. The top plate portion 60 and the bottom plate portion 70 are connected so that both ends having an arc shape extend in a tangential direction of both ends when viewed in cross section from the sizing portion 81.

As shown in fig. 3 and 5, the diameter-enlarged portion 82 is connected to an end of the diameter-fixed portion 81 and extends from the end of the diameter-fixed portion 81 to an end of the side plate unit 50. In other words, the sizing portion 81 extends from the enlarged diameter portion 82 to the side opposite to the end portion side of the side plate unit 50.

The diameter-enlarged portion 82 is enlarged in diameter such that the curvature radius R, which is circular in shape when viewed in cross section from the connecting portion with the sizing portion 81 separated from the end portion of the side plate unit 50, gradually increases toward the end portion of the side plate unit 50. The diameter-enlarged portion 82 is gradually increased in width (corresponding to the distance between the lower end 61 of the top plate portion 60 and the upper end 71 of the bottom plate portion 70 facing each other) over the top plate portion 60 and the bottom plate portion 70 from the connecting portion with the diameter-defined portion 81 toward the end of the side plate unit 50. That is, the width of the enlarged diameter portion 82 is enlarged toward the end of the side panel unit 50. The diameter-enlarged portion 82 has an arc-shaped curvature radius R and width dimensions in a cross-sectional view at a portion connected to the diameter-fixed portion 81, which are the same as those of the diameter-fixed portion 81.

As the width of the enlarged diameter portion 82 is enlarged, the lower end 61 of the top plate portion 60 and the upper end 71 of the bottom plate portion 70 connected by the enlarged diameter portion 82 are retracted so as to be spaced apart from each other. The portions of the lower end 61 of the top plate 60 and the upper end 71 of the bottom plate 70 that have retreated in this manner are retreated portions 63 and 73. The receding portions 63 and 73 are connected to the parallel portions 62 and 72. Thus, the top plate portion 60 and the bottom plate portion 70 are connected so that both ends having an arc shape extend in the tangential direction of both ends when viewed in cross section from the enlarged diameter portion 82 over the entire extension direction of the enlarged diameter portion 82.

With the plurality of side panel units 50 of this structure, the bow-to-stern direction ends of each other are joined to each other by welding. At this time, the side plate units 50 adjacent to each other are arranged so as to intersect each other in a plan view. The mutually adjacent side plate units 50 extend toward the outside of the cargo tank 30A as they approach each other, respectively. That is, the posture of the side plate units 50 joined to each other is set to a posture in which the side walls 40 formed by joining the side plate units 50 project outward of the cargo tank 30A.

In the adjacent side panel units 50, the ship's fore-aft direction end portions of the roof panel sections 60 are joined to each other in the vertical direction. The respective fore-and-aft ends of the bottom plate portions 70 are vertically joined to each other. The end portions of the enlarged diameter portion 82 of the curved member 80 in the fore-and-aft direction are vertically joined to each other. That is, the adjacent side plate units 50 are joined to each other so that the top plate portions 60, the bottom plate portions 70, and the diameter-enlarged portions 82 correspond to each other.

The side plate units 50 projecting outward of the cargo tank 30A in a cross-sectional view orthogonal to the bow-to-stern direction are joined to each other so as to project outward of the cargo tank 30A in a plan view. Thereby, the side wall 40 has a shape in which a part thereof protrudes outward of the cargo tank 30A as the protruding portion P. The projecting portion P is not a portion of the enlarged diameter portion 82 of each side plate unit 50. The projection P is closest to the side shell 11a that partitions the cargo tank 30A.

Next, the operation and effects of the present embodiment will be described.

in the ship 100 as described above, it is required to ensure that the distance between the side wall 40 of the cargo tank 30A and the side shell 11a of the hull 10 is equal to or greater than a predetermined value according to the regulations. That is, the side wall 40 of the cargo tank 30A cannot intrude further toward the side of the side outer panel 11a than the reference line S (refer to fig. 6) spaced apart from the side outer panel 11a toward the cargo tank 30A side by a constant distance.

According to the present embodiment, the radius of curvature R of the curved member 80 (the radius of curvature R of the enlarged diameter portion 82) at the end portion of the side panel unit 50 in the bow-to-stern direction becomes larger as it approaches the end portion. At the same time, the width of the bending member 80 increases as it approaches the end, and the lower end 61 of the top plate 60 and the upper end 71 of the bottom plate 70 are retracted as the width increases. Therefore, as shown in fig. 6, the top plate portion 60 and the bottom plate portion 70 are smoothly connected in the tangential direction of both ends of the curved member 80 by the curved member 80, and the amount of projection of the curved member 80 in the end portion of the side panel unit 50 in the bow-tail direction can be suppressed. Therefore, even when the portion of the curved member 80 at the end of the side plate unit 50 is close to the side outer panel 11a, the distance between the curved member 80 and the side outer panel 11a can be secured. Therefore, the side wall 40 of the cargo tank 30A can be prevented from moving closer to the side outer panel 11a beyond the reference line S.

Here, assuming that the arc-shaped radius of curvature R of the curved member 80 is constant over the entire extension direction region of the curved member 80, the amount of projection of the curved member 80 at the end of the side panel unit 50 is large. That is, if the curvature radius R having an arc shape in a cross-sectional view of the curved member 80 is constant without increasing the diameter, the amount of projection of the curved member 80 at the end of the side panel unit 50 cannot be suppressed as shown by the two-dot chain line in fig. 6. As a result, the side wall 40 of the cargo tank 30A is caused to go beyond the reference line S.

In addition, if the curvature radius R of the curved member 80 in the shape of an arc is constant in the cross-sectional view and a distance from the side shell 11a is to be secured, for example, as shown in fig. 7 for comparison, in order to separate each side plate unit 50 from the side shell 11a, it is necessary to perform redesign to retreat the side plate unit 50 to the inside of the cargo tank 30A. That is, it is necessary to redesign from the line indicated by the dotted line in fig. 7 to the line indicated by the solid line. In this case, the top plate portion 60 and the bottom plate portion 70 that define the storage space of the cargo tank 30A are positioned inside the cargo tank 30A. This results in a reduction in the volume of the storage space of the cargo tank 30A.

In contrast, in the present embodiment, the penetration of the reference line S is avoided only by enlarging the curvature radius R and the width dimension of the bow-aft direction end portion of the curved member 80 constituting the projecting portion P. Therefore, it is not necessary to move the positions of the top plate 60 and the bottom plate 70 to the inside of the cargo tank 30A. Therefore, the volume of the cargo tank 30A can be secured largely.

Further, when the enlarged diameter portion 82 is provided beyond the necessary portion, or when the curvature radius R that is circular-arc-shaped in the cross-sectional view of the curved member 80 is simply enlarged over the entire region, the capacity of the cargo tank 30A corresponding to the increase in the circular-arc-shaped large diameter portion of the curved member 80 is eroded in vain. In contrast, in the present embodiment, the portion of the curved member 80 that can secure a distance from the side shell 11a is the fixed diameter portion 81 that extends continuously with a constant radius of curvature R and width dimension on the smaller diameter side of the enlarged diameter portion 82, and thus an inadvertent reduction in the volume of the cargo tank 30A can be avoided.

When the pair of side plate units 50 are joined to each other as in the present embodiment, the portion where the pair of top plate portions 60 and the pair of bottom plate portions 70 are gathered is closest to the side shell 11a as the protruding portion P. In the present embodiment, since the projecting portion P is formed by the enlarged diameter portion 82 of the bending member 80, the amount of projection to the side shell 11a can be suppressed. This ensures that the distance between the side wall 40 and the side outer panel 11a is kept constant or longer, and the volume of the cargo tank 30A can be maintained large.

While the embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and modifications can be made as appropriate without departing from the technical spirit of the present invention.

For example, in the embodiment, in order to suppress the amount of projection of the projection P formed between the pair of side plate units 50 adjacent to each other, the end of the curved member 80 forming the projection P is provided with the enlarged diameter portion 82. However, the present invention is not limited to this, and for example, the present invention may be applied to a corner portion formed by joining the side plate unit 50 and the end wall 35 to each other. That is, the side plate unit 50 in which the end portions of the bending member 80 are expanded in diameter does not necessarily have to be provided in a pair.

in addition, the present invention can be applied to any location as long as the end of the side panel unit 50 is joined.