JP5384425B2 - Construction machinery tank - Google Patents

Description

  The present invention relates to a tank of a construction machine that is suitably used as a hydraulic oil tank or the like mounted on a construction machine such as a hydraulic excavator.

  In general, a hydraulic excavator as a representative example of a construction machine is a self-propelled lower traveling body, an upper revolving body that is swingably mounted on the lower traveling body, and can be raised and raised on the front side of the upper revolving body. The work device is generally configured, and the work device is moved up and down while turning the upper turning body to perform excavation work of earth and sand.

  The hydraulic excavator includes various hydraulic actuators such as a hydraulic motor for traveling the lower traveling body, a hydraulic motor for pivoting the upper swing body, a hydraulic cylinder for operating the boom, arm, and bucket of the working device. Is installed. The hydraulic oil supplied to these hydraulic actuators is stored in a hydraulic oil tank provided on a revolving frame that is a base of the upper revolving body, and the hydraulic oil in the hydraulic oil tank is sucked by a hydraulic pump, The hydraulic excavator is configured to perform a traveling operation, a turning operation, excavation work, and the like by being pumped to the actuator.

  Here, the hydraulic oil tank includes, for example, a cylindrical body that is formed in a cylindrical shape extending upward and downward by bending one flat plate and joining both ends thereof, and a bottom plate that closes the lower end portion of the cylindrical body And an upper plate that closes the upper end of the cylinder is known. (For example, refer to Patent Document 1).

  Further, as a cylindrical body constituting the hydraulic oil tank, for example, one in which the end portions of two members formed in a U-shape are butted and joined by butt welding is known. (For example, refer to Patent Document 2).

JP 2001-146765 A JP 2005-140305 A

  By the way, when the cylinder constituting the hydraulic oil tank is formed from a single flat plate, the flat plate is curved into a cylindrical shape and the edges of both ends are butted in the circumferential direction, and the edges are butt welded. It is possible to join. However, since the flat plate is a thin plate, the work of butt welding is troublesome (difficult), and the cost may increase.

  On the other hand, it is also conceivable to join the two end portions by welding from the outside of the cylindrical body in a state in which the flat plate is bent into a cylindrical shape and the both end portions are overlapped in the radial direction. However, in this case, there is a possibility that rust is generated at the overlapping portion of both ends of the flat plate constituting the cylindrical body.

  That is, after the hydraulic oil tank is formed, the inside of the hydraulic oil tank is washed to remove dirt, foreign matter, and the like attached at the time of formation. At this time, the cleaning liquid enters the inside of the overlapped portion, that is, between the contact surfaces of the overlapping portions that are in contact with each other (a minute gap) by capillary action, and the cleaning liquid is placed between the contact surfaces over a long period of time. May remain. In this case, rust is generated at the overlapping portion, and the durability and reliability of the hydraulic oil tank may be reduced.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a tank for a construction machine that can suppress the generation of rust due to the remaining cleaning liquid inside.

  In order to solve the above-described problems, the present invention is mounted on a construction machine, and a cylindrical body that is formed in a cylindrical shape that extends upward and downward by bending one flat plate and joining both ends thereof, The present invention is applied to a tank of a construction machine including a bottom plate that closes a lower end portion of a cylinder and an upper plate that closes an upper end portion of the cylinder.

A feature of the configuration adopted by the invention of claim 1 is that, when the cylindrical body is formed by curving the flat plate at one end of the flat plate forming the cylindrical body, A bent portion that forms a gap is provided in the overlapping portion with the other end portion, and the bent portion is formed inward from the inner peripheral surface of the cylindrical body when the cylindrical body is formed by curving the flat plate. a folding bend configured to protrude, the other end of the flat plate is that was you welded structure from the outside of the tubular body to bend starting position of the bent portion.

On the other hand , the feature of the configuration adopted by the invention of claim 2 is that one end portion of the flat plate forming the cylindrical body has one end portion when the flat body is curved to form the cylindrical body. the a fold portion to form a gap provided in overlapping portions of the other end portion, the bent portion abuts against the inner peripheral surface of the cylindrical body when it is bent the flat plate to form the tubular body The other end of the flat plate is welded from the outside of the cylindrical body to a position slightly away from the bent portion.

  According to invention of Claim 1, since it is set as the structure which provides a bending part in one edge part of the flat plate which forms a cylinder, when the cylinder is formed by curving a flat plate, A gap is formed at the overlapping portion with the other end. That is, due to the presence of the bent portion, a gap is formed between the side surfaces of the one end portion and the other end portion that constitute the overlapping portion that face each other. The gap can make it difficult for capillary action to occur between the side surfaces of the overlapping portion facing each other, and the cleaning liquid can be easily discharged from between the side surfaces.

  As a result, it is possible to suppress the generation of rust due to the cleaning liquid remaining in the overlapping portion, and the durability and reliability of the tank can be improved. In addition, the bent portion for forming the gap in the overlapped portion can be easily formed by bending the flat plate forming the cylindrical body, so that a configuration that can easily discharge the cleaning liquid is low cost. Can be obtained at

In addition , the bent portion is configured to bend so as to protrude inward from the inner peripheral surface of the cylindrical body when the cylindrical body is formed by curving the flat plate, so that one end portion constituting the overlapping portion A gap can be formed between the side surfaces of the bent portion and the other end facing each other, and the cleaning liquid can be easily discharged from the overlapped portion through the gap.

On the other hand , according to the invention of claim 2 , since the bent portion is configured to bend so as to contact the inner peripheral surface of the cylindrical body when the flat body is bent to form the cylindrical body, the overlapping portion A gap can be formed between the opposite side surfaces of the other end portion and the other end portion of the other end portion of the bent portion, and the cleaning liquid is discharged from the overlapped portion through this gap. Can be made easier.

It is a perspective view which shows the hydraulic shovel carrying the hydraulic oil tank by the reference example of this invention. It is the top view which looked at the hydraulic excavator from the upper part. It is an expansion perspective view of the turning frame shown in a state where the hydraulic oil tank is removed. It is a perspective view which expands and shows a hydraulic oil tank. It is a perspective view which shows the state which provided the bending part in the flat plate which comprises a cylinder. It is a perspective view which shows the state which curved the flat plate and formed the cylinder. It is a top view which shows the state which provided the bending part in the flat plate which comprises a cylinder. It is a top view which shows the state which curved the flat plate and formed the cylinder. It is the A section enlarged view in FIG. 8 which shows the junction part of a cylinder. 1 is a perspective view showing a hydraulic oil tank according to a first embodiment of the present invention. It is a perspective view which shows the state which provided the bending part in the flat plate which comprises a cylinder. It is a perspective view which shows the state which curved the flat plate and formed the cylinder. It is a top view which shows the state which provided the bending part in the flat plate which comprises a cylinder. It is a top view which shows the state which curved the flat plate and formed the cylinder. It is the B section enlarged view in FIG. 14 which shows the junction part of a cylinder. It is a partially broken front view which shows the lower end side of a hydraulic oil tank. It is a top view similar to FIG. 9 which shows the junction part of the cylinder by the 2nd Embodiment of this invention . It is a top view similar to FIG. 9 which shows the junction part of the cylinder by the 3rd Embodiment of this invention .

  Hereinafter, the embodiment of the tank of the construction machine according to the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where the embodiment is applied to a hydraulic oil tank mounted on a hydraulic excavator.

First, FIG. 1 thru | or FIG. 9 has shown the reference example of this invention. In the figure, reference numeral 1 denotes a hydraulic excavator as a typical example of a construction machine. The hydraulic excavator 1 is a self-propelled crawler-type lower traveling body 2 and an upper swing that is rotatably mounted on the lower traveling body 2. The main body 3 and the working device 4 provided on the front side of the upper swing body 3 are generally configured and are suitably used for earth and sand excavation work and the like.

  The working device 4 includes a boom 4A attached to the upper swing body 3, an arm 4B attached to the distal end side of the boom 4A, a bucket 4C attached to the distal end side of the arm 4B, and an upper swing body. 3 and a boom cylinder 4D provided between the boom 4A, an arm cylinder 4E provided between the boom 4A and the arm 4B, and a bucket cylinder 4F provided between the arm 4B and the bucket 4C. It is roughly structured.

  Reference numeral 5 denotes a revolving frame that serves as a base of the upper revolving structure 3, and as shown in FIG. 3, the revolving frame 5 stands on a bottom plate 5A made of a thick steel plate or the like extending in the front and rear directions, and on the bottom plate 5A. Left and right vertical plates 5B and 5C extending in the front and rear directions while facing each other at a predetermined interval in the left and right directions, and a left side frame disposed on the left side of the left vertical plate 5B and extending in the front and rear directions 5D, a right side frame 5E disposed on the right side of the right vertical plate 5C and extending in the front and rear directions, and between the bottom plate 5A and the left vertical plate 5B and the left side frame 5D, and between the bottom plate 5A and the right vertical plate 5C and the right side The plurality of overhanging beams 5F that connect with the frame 5E are roughly configured to form a strong support structure.

  A cab 6 that defines a driver's cab is disposed on the left side of the front portion of the swivel frame 5, and a counterweight 7 that balances the weight of the work device 4 is disposed on the rear end side of the swivel frame 5. Has been. In addition, a building cover 8 is provided on the front side of the counterweight 7 to accommodate equipment (not shown) such as an engine, a hydraulic pump, and a heat exchange device. Further, a hydraulic oil tank 11 described later is disposed on the right front side of the building cover 8, and a fuel tank 9 for storing fuel is disposed on the front side of the hydraulic oil tank 11.

  Reference numeral 11 denotes a hydraulic oil tank as a tank provided on the revolving frame 5 and positioned on the right front side of the building cover 8. The hydraulic oil tank 11 includes a traveling hydraulic motor provided in the lower traveling body 2 and an upper part. Hydraulic oil supplied to each hydraulic actuator such as a boom cylinder 4D, an arm cylinder 4E, and a bucket cylinder 4F constituting the working device 4 is stored. To do. The hydraulic oil tank 11 is roughly constituted by a cylinder 12, which will be described later, a bottom plate 17, and an upper plate 19, as shown in FIGS.

  Reference numeral 12 denotes a cylinder that extends in the upward and downward directions and is open at both upper and lower ends. As shown in FIGS. 5 to 8, the cylinder 12 includes a single flat plate 13 made of a metal plate such as a steel plate. It is formed in a cylindrical shape by bending both ends 13A and 13B of the flat plate 13 by bending by roll processing or the like.

  Reference numeral 14 denotes one end portion 13A of the flat plate 13 forming the cylindrical body 12, that is, an end that becomes the inner side in a state in which the flat plate 13 is curved in a cylindrical shape and both end portions 13A and 13B are overlapped in the radial direction of the cylindrical body 12. The bending part provided in the part 13A is shown. Here, as shown in FIG. 8, when the bent portion 14 is formed by bending the flat plate 13 to form the cylindrical body 12, there is a gap in the overlapping portion 12A between the one end portion 13A and the other end portion 13B. This is for forming S.

  Therefore, the bent portion 14 is formed on one end 13A of the flat plate 13 so as to protrude inward from the inner peripheral surface of the cylindrical body 12 when the cylindrical body 12 is formed by curving the flat plate 13. It is bent and formed. In other words, the bent portion 14 is formed so as to protrude from the side surface 13C serving as the inner peripheral surface in a state of being curved in a cylindrical shape among the side surfaces 13C and 13D of the flat plate 13. Further, as shown in FIGS. 5 and 7, the bent portion 14 is bent at one end 13 </ b> A of the flat plate 13 by, for example, pressing, before the flat plate 13 is bent into a cylindrical shape. It is formed by applying a bending process or the like.

  Reference numeral 15 denotes a welded portion that joins both end portions 13A and 13B of the flat plate 13 constituting the cylindrical body 12, and the welded portion 15 is an end edge of the other end portion 13B of the flat plate 13 and a bending start position of the bent portion 14. Between 14A, it forms by welding, for example using means, such as arc welding. Then, with the welded portion 15 joining the edge of the other end portion 13B of the flat plate 13 and the folding start position 14A of the folded portion 14, the inside of the overlapping portion 12A of the cylindrical body 12, that is, the folded portion A gap S is formed between the side surfaces of the portion 14 and the other end portion 13B facing each other.

  Reference numeral 16 denotes a mating margin of the joint between the other end 13B and one end 13A of the flat plate 13. The mating margin 16 includes a side surface 13C (tubular body 12) of the other end 13B as shown in FIG. The inner surface of the bent portion 14 is brought into contact (surface contact) with the bending start position 14A of the bent portion 14.

  Reference numeral 17 denotes a bottom plate that closes the lower end portion of the cylindrical body 12. The bottom plate 17 has a rectangular metal plate (for example, a steel plate) whose four sides have a length substantially equal to or larger than the outer diameter of the cylindrical body 12. It is formed by. And the baseplate 17 is attached to the overhang | projection beam 5F of the turning frame 5, for example, as shown in FIG. The bottom plate 17 is provided with a supply port 17A for supplying hydraulic oil to the suction side of the hydraulic pump.

  Reference numeral 18 denotes a welded portion that joins the lower end edge of the cylindrical body 12 and the upper surface of the bottom plate 17. The welded portion 18 is provided with a means such as arc welding between the lower end edge of the cylindrical body 12 and the upper surface of the bottom plate 17. It is formed by using and welding.

  Reference numeral 19 denotes an upper plate that closes the upper end of the cylindrical body 12, and the upper plate 19 is formed of a rectangular metal plate (for example, a steel plate) having substantially the same size as the bottom plate 17. The upper plate 19 is joined to the upper end side of the cylindrical body 12 by welding similarly to the bottom plate 17. The upper plate 19 is provided with an oil supply port 19A for supplying oil into the hydraulic oil tank 11 from the outside.

  Next, the formation process (manufacturing method) of the hydraulic oil tank 11 will be described.

  First, as shown in FIGS. 5 and 7, the bent portion 14 is formed at one end 13 </ b> A of the flat plate 13 that forms the cylindrical body 12. Here, the bent portion 14 is formed on, for example, one end portion 13A of the flat plate 13 so as to protrude inward from the inner peripheral surface of the cylindrical body 12 when the flat plate 13 is bent to form the cylindrical body 12. It is formed by bending or the like with a press. Here, the bending angle α of the bent portion 14 with respect to the flat plate 13 is such that the bent portion 14 and the other end 13B are joined in a state in which the flat plate 13 is bent into a cylindrical shape and one end 13A and the other end 13B are joined. The value is set such that a necessary gap S can be formed between the side surfaces facing each other with the end portion 13B.

  Then, if the bent portion 14 is formed at one end 13A of the flat plate 13, the flat plate 13 is curved into a cylindrical shape as shown in FIGS. 6 and 8, and the flat plate 13 as shown in detail in FIG. The side surface 13C of the other end portion 13B (the surface serving as the inner surface of the cylindrical body 12) is brought into contact with the bending start position 14A of the bending portion 14. That is, the side surface 13C of the other end portion 13B is brought into contact (surface contact) with the bending margin 16 at the bending start position 14A. Next, welding is performed from the outside of the cylindrical body 12 between the end edge of the other end portion 13B and the bending start position 14A, and welding is performed between the end edge of the other end portion 13B and the bending start position 14A. By forming the portion 15, the other end portion 13B and the one end portion 13A are joined. Thus, in the state where the other end portion 13B and the one end portion 13A are joined by welding, a gap S is formed between the side surfaces facing each other of the bent portion 14 and the other end portion 13B. The

The hydraulic excavator 1 according to the reference example has the above-described configuration, and the operation thereof will be described next.

  First, the operator can sit on the driver's seat in the cab 6 and operate the lower traveling body 2 by operating a traveling lever or the like in this state. Further, by operating a working lever or the like, the working device 4 can be moved up and down to perform excavation work of earth and sand.

  Here, in the hydraulic actuators such as the traveling hydraulic motor, the turning hydraulic motor, the boom cylinder 4D, the arm cylinder 4E, and the bucket cylinder 4F constituting the working device 4, the hydraulic oil tank 11 is stored. Hydraulic oil is supplied.

By the way, the cylindrical body 12 constituting the hydraulic oil tank 11 is formed in a cylindrical shape by bending one flat plate 13 and joining one end 13A and the other end 13B of the flat plate 13. Yes. In the case of the reference example , by providing a bent portion 14 at one end 13A of the flat plate 13 forming the cylindrical body 12, a gap S is formed in the overlapping portion 12A of the cylindrical body 12. Thus, the gap S makes it difficult for the capillary phenomenon to occur between the side surfaces of the bent portion 14 and the other end portion 13B facing each other.

  For this reason, even when the cleaning liquid enters the overlapping portion 12A of the cylindrical body 12 when cleaning the hydraulic oil tank 11, the cleaning liquid can be easily discharged from between the mutually facing side surfaces of the bent portion 14 and the other end portion 13B. can do. As a result, it is possible to suppress the occurrence of rust due to the cleaning liquid remaining in the overlapping portion 12A of the cylindrical body 12, and the durability and reliability of the hydraulic oil tank 11 can be improved.

  Moreover, since the bent portion 14 for forming a gap in the overlapped portion 12A of the cylinder 12 can be easily formed by bending the flat plate 13 forming the cylinder 12, the cleaning liquid can be used. A configuration that can be easily discharged can be obtained at low cost.

Next, FIG. 10 to FIG. 16 show a first embodiment of the present invention. The feature of this embodiment is that the bent portion is configured to be bent so as to contact the inner peripheral surface of the cylindrical body. In the first embodiment, the same components as those in the reference example described above are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, reference numeral 21 denotes a hydraulic oil tank for storing hydraulic oil. The hydraulic oil tank 21 closes a cylinder 22 which will be described later, a bottom plate 17 which closes a lower end edge of the cylinder 22, and an upper end edge of the cylinder plate 22. The upper plate 19 is generally configured.

  Reference numeral 22 denotes a cylindrical body that extends in the upward and downward directions and is open at both the upper and lower ends. As shown in FIGS. 11 to 14, the cylindrical body 22 includes a single flat plate 23 made of a metal plate such as a steel plate. It is formed in a cylindrical shape by bending both ends 23A and 23B of the flat plate 23 by bending by roll processing or the like.

  Reference numeral 24 denotes one end portion 23A of the flat plate 23 forming the cylindrical body 22, that is, an end that is inward when the flat plate 23 is curved into a cylindrical shape and both end portions 23A and 23B are overlapped in the radial direction of the cylindrical body 22. The bending part provided in the part 23A is shown. Here, the bent portion 24 is for forming a gap S in the overlapping portion 22A of one end 23A and the other end 23B when the cylindrical body 22 is formed by bending the flat plate 23. It is.

  Therefore, the bent portion 24 is bent at one end portion 23A of the flat plate 23 so as to come into contact with the inner peripheral surface of the cylindrical body 12 when the flat plate 23 is bent to form the cylindrical body 22. Is formed. In other words, the bent portion 24 is bent so as to protrude from the side surface 23D on the side that becomes the outer peripheral surface in a state of being curved in a cylindrical shape among the side surfaces 23C and 23D of the flat plate 23. Further, as shown in FIG. 11 and FIG. 13, the bent portion 24 is bent at one end 23A of the flat plate 23 by, for example, pressing, before the flat plate 23 is bent into a cylindrical shape. It is formed by applying a bending process or the like.

  Furthermore, upper and lower cutouts 24A and 24B are provided at the corners at both ends in the vertical direction of the bent portion 24, respectively. Further, a clearance space having a triangular cross section formed by the upper notch 24A and the inner peripheral surface of the cylindrical body 22 and the lower surface of the upper plate 18, and the lower peripheral notch 24B and the inner peripheral surface of the cylindrical body 22 and For example, the cleaning liquid can be discharged from the overlapping portion 22 </ b> A through a gap space having a triangular cross section formed by the upper surface of the bottom plate 16.

  Reference numeral 25 denotes a welded portion that joins both end portions 23A and 23B of the flat plate 23 constituting the cylindrical body 22, and the welded portion 25 includes an end edge of the other end portion 23B of the flat plate 23 and a side surface of the one end portion 23A. Specifically, it is formed by welding, for example, using means such as arc welding, between the side surface of one end 23A and a position slightly apart from the bent portion 24.

  Then, in a state where the edge of the other end 23B of the flat plate 23 and the side surface of the one end 23A (position slightly separated from the bent portion 24) are joined by the welded portion 25, the overlapping portion of the cylindrical body 22 A gap S is formed inside 22A, that is, between the side surfaces of the other end 23B and one end 23A that face each other.

  Here, as shown in FIG. 15, the length X from the bent portion 24 to the welded portion 25 is, for example, about 1 to 4 times the length Y of the bent portion 24 (Y ≦ X ≦ 4Y). Is preferred. In other words, the length Y of the bent portion 24, the length X from the bent portion 24 to the welded portion 25, and the bending angle β (see FIG. 13) of the bent portion 24 with respect to the flat plate 23 are cylindrical. In the state where one end portion 23A and the other end portion 23B are joined in a curved shape, a necessary gap S is formed between the opposite side surfaces of the other end portion 23B and the one end portion 23A. Set it to a value that you can.

The hydraulic excavator 1 according to the first embodiment is equipped with the hydraulic oil tank 21 as described above. In the case of the present embodiment as well, the hydraulic excavator 1 is folded at the overlapping portion 22A of the cylindrical body 22 constituting the hydraulic oil tank 21. A gap S is formed by the bent portion 24. The gap S makes it difficult for the capillary phenomenon to occur between the side surfaces of the other end 23B and the one end 23A facing each other. For this reason, even when the cleaning liquid enters the overlapping portion 22A of the cylindrical body 22 during the cleaning of the hydraulic oil tank 21, the cleaning liquid is discharged from between the opposite side surfaces of the other end 23B and the one end 23A. Easy to do. Therefore, also in 1st Embodiment, the effect similar to the reference example mentioned above can be acquired.

In the reference example described above, the side surface 13C of the other end portion 13B of the flat plate 13 (the side surface serving as the inner side surface of the cylindrical body 12) is brought into contact with the bending start position 14A of the bending portion 14 with the alignment margin 16, The case where the welded portion 15 is formed at the edge of the other end portion 13 and the bending start position 14A has been described as an example. However, as in the second embodiment of the present invention shown in FIG. 17 if example embodiment, the bent starting position 14A (the side surface of the bent portion 14 of the other end bent portion 14 of the edge of the 13B of the plate 13 It is good also as a structure which forms the welding part 15 'in the said contact part (butting part).

Moreover, in the reference example mentioned above, the case where the bending part 14 was formed in linear form was mentioned as an example , and was demonstrated. However, as in the third embodiment of the present invention shown in FIG. 18 if example embodiment, the bent portion 14 'may be configured to bend with a small radius of curvature R2 than the radius of curvature R1, for example the barrel 12. In this case, for example, the base end portion of the bent portion 14 ′ is smoothly continuous with the cylindrical body 12, and the bent portion becomes a smoothly continuous portion (a portion where the radius of curvature smoothly changes from R 2 to R 1). The edge of the other end 13B of the flat plate 13 is joined to the start position 14A ′ by welding.

In the reference example described above, the case where the other end 13B of the flat plate 13 is brought into contact with the folding start position 14A of the bent portion 14 with the alignment margin 16 (surface contact) has been described as an example. However, as in the third embodiment of the present invention shown in FIG. 18 if example embodiment, causes 'bent starting position 14A' of the point contact the other end portion 13B of the bent portion 14 of the plate 13 (line contact) It is good also as a structure. That is, the point contact portion 31 may be welded in a state where the end edge of the other end portion 13B is brought into contact with the bending start position 14A ′ with the point contact portion 31.

Moreover, in the reference example and each embodiment mentioned above, the case where it applies to the hydraulic oil tanks 11 and 21 mounted in the hydraulic excavator 1 is illustrated. However, example if hydraulic crane, can be widely applied to hydraulic oil tank mounted to other construction machines such as a wheel loader. Further, the present invention is not limited to the hydraulic oil tank, and can be applied to, for example, a tank that stores liquids other than hydraulic oil, and more specifically, other tanks such as a fuel tank that stores fuel.

1 Excavator (construction machine)
11, 21 Hydraulic oil tank (tank)
12, 22 Cylinder 12A, 22A Overlapping portion 13, 23 Flat plate 13A, 23A One end 13B, 23B The other end 14, 14 ', 24 Bending part 14A, 14A' Bending start position 15, 15 ' , 25 Welded part 17 Bottom plate 19 Top plate S Gap

Claims (2)

A cylindrical body that is mounted on a construction machine and that is formed in a cylindrical shape that extends upward and downward by bending one flat plate and joining both ends thereof, and a bottom plate that closes a lower end portion of the cylindrical body, In the tank of a construction machine consisting of an upper plate that closes the upper end of the cylinder,
At one end of the flat plate forming the cylindrical body, when the flat body is bent to form the cylindrical body, a gap is formed in the overlapping portion of the one end and the other end. Bends ,
The bent portion is configured to bend so as to protrude inward from the inner peripheral surface of the cylindrical body when the cylindrical body is formed by curving the flat plate,
The other end of the flat plate, the tank of a construction machine, characterized in that the you welded structure from the outside of the tubular body to bend starting position of the bent portion. A cylindrical body that is mounted on a construction machine and that is formed in a cylindrical shape that extends upward and downward by bending one flat plate and joining both ends thereof, and a bottom plate that closes a lower end portion of the cylindrical body, In the tank of a construction machine consisting of an upper plate that closes the upper end of the cylinder,
At one end of the flat plate forming the cylindrical body, when the flat body is bent to form the cylindrical body, a gap is formed in the overlapping portion of the one end and the other end. Bends,
The bent portion includes a configuration bending so as to contact the inner circumferential surface of the cylindrical body when by bending the flat plate to form the cylindrical body,
A tank for a construction machine, wherein the other end of the flat plate is welded from the outside of the cylindrical body to a position slightly away from the bent portion.

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