Patent Application
20250041921
This application claims priority to and the benefit of Japanese Patent Application No. 2023-125513 filed on Aug. 1, 2023, with the Japan Patent Office, the entire disclosure of which is incorporated herein by reference.
The present disclosure relates to a method of manufacturing a pipe.
As described in Japanese Unexamined Patent Application Publication No. 2021-070040, there is a known technique of forming a pipe, by UO-shape bending, that includes a large-diameter portion, a small-diameter portion having a smaller diameter than the large-diameter portion, and a gradually-reduced-diameter portion connecting the large-diameter portion and the small-diameter portion to each other.
However, if a diameter of the large-diameter portion is increased or a length of the gradually-reduced-diameter portion in pipe extension directions is shortened, buckling may occur at the gradually-reduced-diameter portion during O-shape bending.
In one aspect of the present disclosure, it is desirable to inhibit occurrence of buckling.
One aspect of the present disclosure is a method of manufacturing a pipe extending along an axis of the pipe. The method comprises forming a blank material, which is a metal plate-shaped member, into a U-shaped member, the U-shaped member extending along the axis and having a cross-section, orthogonal to the axis, of U-shape; and forming the U-shaped member into a shape of the pipe. The pipe includes a large-diameter portion, a small-diameter portion, and a gradually-reduced-diameter portion. The large-diameter portion has the cross-section with a relatively large diameter. The small-diameter portion has the cross-section with a relatively small diameter. The gradually-reduced-diameter portion connects the large-diameter portion and the small-diameter portion to each other, and a diameter of the cross-section of the gradually-reduced-diameter portion is gradually reduced toward the small-diameter portion. The method of manufacturing the pipe further comprises forming at least one bead in a part, of the blank material or the U-shaped member, that corresponds to the gradually-reduced-diameter portion, the at least one bead extending along the axis of the pipe.
According to the aforementioned configuration, the at least one bead improves stiffness of a part of the blank material that corresponds to the gradually-reduced-diameter portion. This makes it possible to inhibit occurrence of buckling when the U-shaped member is formed into the shape of the pipe.
In one aspect of the present disclosure, the U-shaped member has a first end portion including a first end of the cross-section of the U-shaped member and a second end portion including a second end of the cross-section of the U-shaped member. The method of manufacturing a pipe may further comprise bending the first end portion and the second end portion of the U-shaped member so that the first end and the second end come closer to each other. The at least one bead may be formed in the first end portion and/or the second end portion when bending the first end portion and the second end portion.
According to the aforementioned configuration, it is possible to form the at least one bead in the gradually-reduced-diameter portion in a favorable manner.
In one aspect of the present disclosure, the pipe may further include a butted portion where a first end and a second end of the cross-section of the U-shaped member are joined together. At least two beads may be formed in the part, of the blank material or the U-shaped member, that corresponds to the gradually-reduced-diameter portion, and when the U-shaped member is formed into the shape of the pipe, two beads of the at least two beads may be arranged in the gradually-reduced-diameter portion so as to have the butted portion therebetween.
The aforementioned configuration allows the beads to be provided at a portion where stress is likely to be concentrated when the U-shaped member is formed into the shape of the pipe. This makes it possible to inhibit occurrence of buckling in a more favorable manner.
In one aspect of the present disclosure, when the U-shaped member is formed into the shape of the pipe, the two beads may extend along the butted portion in a periphery of the butted portion in the gradually-reduced-diameter portion.
The aforementioned configuration allows the beads to be provided at a portion where stress is likely to be concentrated when the U-shaped member is formed into the shape of the pipe. This makes it possible to inhibit occurrence of buckling in a more favorable manner.
In one aspect of the present disclosure, when the U-shaped member is formed into the shape of the pipe, the two beads may pass a boundary of the gradually-reduced-diameter portion with the large-diameter portion in the pipe or may pass a vicinity of the boundary.
The aforementioned configuration allows the beads to be arranged at a portion where stress is likely to be concentrated when the U-shaped member is formed into the shape of the pipe. This makes it possible to inhibit occurrence of buckling in a more favorable manner.
In one aspect of the present disclosure, when the U-shaped member is formed into the shape of the pipe, the at least one bead may pass a boundary of the gradually-reduced-diameter portion with the large-diameter portion in the pipe or may pass a vicinity of the boundary.
The aforementioned configuration allows the beads to be arranged at a portion where stress is likely to be concentrated when the U-shaped member is formed into the shape of the pipe. This makes it possible to inhibit occurrence of buckling in a more favorable manner.
In one aspect of the present disclosure, the pipe may further include a butted portion where a first end and a second end of the cross-section of the U-shaped member are joined together. When the U-shaped member is formed into the shape of the pipe, the at least one bead may extend along the butted portion in a periphery of the butted portion in the gradually-reduced-diameter portion.
The aforementioned configuration allows the beads to be arranged at a portion where stress is likely to be concentrated when the U-shaped member is formed into the shape of the pipe. This makes it possible to inhibit occurrence of buckling in a more favorable manner.
In one aspect of the present disclosure, the pipe may be mounted in a vehicle.
The aforementioned configuration makes it possible to inhibit occurrence of the buckling in a manufacturing process of a member to be mounted in a vehicle.
In one aspect of the present disclosure, the pipe may be used in an instrument panel reinforcement of the vehicle.
The aforementioned configuration makes it possible to inhibit occurrence of the buckling in a manufacturing process of the instrument panel reinforcement.
An embodiment of the present disclosure will be described hereinafter with reference to the accompanying drawings, in which:
Hereinafter, example embodiments of the present disclosure will be described with reference to the accompanying drawings.
As shown in
The pipe 1 as the instrument panel reinforcement has a large-diameter portion 10 (details of which will be described later). Joined to one end of large-diameter portion 10, which is adjacent to a gradually-reduced-diameter portion 12, is an upper end of a framework bracket 16. A lower end of the framework bracket 16 is joined to a vehicle body, and the framework bracket 16 supports the instrument panel reinforcement from below.
The pipe 1 has a cylindrical shape extending straight along an axis A of the pipe 1, and a cross-section orthogonal to the axis A (hereinafter also simply referred to as “the cross-section”) is substantially circular, in one example. The cross-section of the pipe 1 may be substantially elliptical, in one example. The pipe 1 comprises the large-diameter portion 10, a small-diameter portion 11, and the gradually-reduced-diameter portion 12 (see
In each of the large-diameter portion 10 and the small-diameter portion 11, a diameter of the cross-section is substantially uniform. The diameter of the cross-section of the large-diameter portion 10 is larger than the diameter of the cross-section of the small-diameter portion 11. Further, in one example, the large-diameter portion 10 extends to a first end of the pipe 1, and the small-diameter portion 11 extends to a second end of the pipe 1.
The gradually-reduced-diameter portion 12 is a portion connecting the large-diameter portion 10 and the small-diameter portion 11 to each other. The gradually-reduced-diameter portion 12 is formed in a tapered shape, and a diameter of the cross-section of the gradually-reduced-diameter portion 12 is gradually reduced toward the small-diameter portion 11 at a substantially constant rate. Obviously, without being limited to the above, the rate at which the diameter of the cross-section of the gradually-reduced-diameter portion 12 is gradually reduced toward the small-diameter portion 11 may vary.
In one example, in the present embodiment, the axis A passes through a substantial center of the cross-section of each of the large-diameter portion 10, the small-diameter portion 11, and the gradually-reduced-diameter portion 12. However, without being limited to the above, the large-diameter portion 10, the small-diameter portion 11, and the gradually-reduced-diameter portion 12 may each have an eccentric configuration. More specifically, a center of the cross-section of the large-diameter portion 10 and a center of the cross-section of the small-diameter portion 11 do not exist on the same straight line, and a center of the cross-section of the gradually-reduced-diameter portion 12 may be positioned on a straight line extending in directions that are different from directions in which the large-diameter portion 10 and the small-diameter portion 11 extend.
Formed on the pipe 1 is a butted portion 14, which extends along the axis A. The butted portion 14 is a portion formed by welding both ends of a blank material in width directions thereof, in other words, both ends of the cross-section of a U-shaped member, which have come to face each other by a later-described UO-shape bending.
In one example, the pipe 1 has a substantially uniform plate thickness. However, without being limited to the above, the pipe 1 may include two or more portions whose plate thicknesses are different from each other. Further, in one example, the pipe 1 is made of a single metal material; however, it may include two or more portions that are made of different metal materials. Furthermore, a flat seat may be formed on an outer circumferential surface of the pipe 1. The flat seat is a flat portion to which something such as other members are attached.
In one example, two beads 13 are formed in the gradually-reduced-diameter portion 12 (see
The two beads 13 are arranged side by side in a circumferential direction of the pipe 1 around the axis A (hereinafter also simply referred to as “the circumferential direction”) so as to have the butted portion 14 between them, and are positioned in the periphery of the butted portion 14. Further, each of the beads 13 extends along the butted portion 14. More specifically, distances between each of the beads 13 and the butted portion 14 in the circumferential direction are substantially uniform, and, in one example, each of the beads 13 extends substantially parallel to the butted portion 14.
Each of the beads 13 extends from a boundary of the gradually-reduced-diameter portion 12 with the large-diameter portion 10 (hereinafter referred to as “the first end”) or its vicinity to a boundary of the gradually-reduced-diameter portion 12 with the small-diameter portion 11 (hereinafter referred to as “the second end”) or its vicinity. However, without being limited to the above, each of the beads 13 may extend from the first end of the gradually-reduced-diameter portion 12 or its vicinity to a position away from the second end of the gradually-reduced-diameter portion 12, or, on the contrary, each of the beads 13 may extend from the second end of the gradually-reduced-diameter portion 12 or its vicinity to a position away from the first end of the gradually-reduced-diameter portion 12. In addition to the above, both ends of each of the beads 13 may be away from both ends of the gradually-reduced-diameter portion 12.
In one example, the beads 13 are provided only in the gradually-reduced-diameter portion 12. However, without being limited to the above, the beads 13 may extend to the large-diameter portion 10 and/or the small-diameter portion 11.
Further, one bead 13, or three or more beads 13 aligned in the circumferential direction, may be provided in the gradually-reduced-diameter portion 12. Furthermore, a plurality of the beads 13 may be provided in the gradually-reduced-diameter portion 12 so as to be aligned in axis A directions. Specifically, for example, the beads 13 may each be provided in the vicinity of the first end and the vicinity of the second end, respectively, of the gradually-reduced-diameter portion 12.
The pipe 1 is manufactured by press forming (namely, UO-shape bending) on a flat-plate-shaped metal member. The method of manufacturing the pipe 1 comprises (1) a blank step, (2) a U-shape bending step, (3) an end bending step, (4) an O-shape bending step, and (5) a welding step. In the present manufacturing method, the beads are formed in a step prior to (4) the O-shape bending step.
In the blank step, a flat-plate-shaped metal member is cut to form a blank material 2 (see
The wide width portion 20 is a portion for forming the large-diameter portion 10 of the pipe 1, and has a substantially rectangular shape that extends along the axis A. In the wide width portion 20, a length in directions orthogonal to the axis A (hereinafter referred to as “the width”) is substantially uniform.
The narrow width portion 21 is a substantially rectangular portion for forming the small-diameter portion 11 of the pipe 1, and has the width that is substantially uniform. The width of the narrow width portion 21 is narrower than the width of the wide width portion 20.
The gradually-reduced-width portion 22 is a portion for forming the gradually-reduced-diameter portion 12 of the pipe 1. The gradually-reduced-width portion 22 is a portion connecting the wide width portion 20 and the narrow width portion 21 to each other, and has the width that is gradually reduced toward the narrow width portion 21.
In the U-shape bending step, the blank material 2 is bent into a U-shape by press forming using a first die 30 and a second die 35 (see
In the U-shape bending step, the first die 30 and the second die 35 are positioned such that the recess 31 and the projection 36 face each other. In one example, the first die 30 is positioned above and the second die 35 is positioned below; however, positions of the first die 30 and the second die 35 may be determined appropriately. The blank material 2 is positioned between the first die 30 and the second die 35.
Then, the first die 30 and the second die 35 are brought close to each other to allow the projection 36 to enter the recess 31. This causes the blank material 2 to get pressed between the projection 36 and the recess 31 to form the U-shaped member 4 (see
The U-shaped member 4 extends along the axis A and has the cross-section of U-shape. Of the U-shaped member 4, parts corresponding to the wide width portion 20, the narrow width portion 21, and the gradually-reduced-width portion 22 of the blank material 2 are referred to as a wide width portion 40, a narrow width portion 41, and a gradually-reduced-width portion 42, respectively. The U-shaped member 4 has a first end portion 43 including a first end 44 of the cross-section of the U-shaped member 4, and a second end portion 45 including a second end 46 of the cross-section of the U-shaped member 4. The first end 43 and the second end 45 extend from a first end to a second end of the U-shaped member 4 in the axis A directions. The wide width portion 40, the narrow width portion 41, and the gradually-reduced-width portion 42 each include the first end 43 and the second end 45. A portion curved in a U-shape in the cross-section of the U-shape member 4 will be described as a bottom 47.
In the present embodiment, in one example, only the bottom 47 is curved in the cross-section of the U-shaped member 4. However, without being limited to the above, a plurality of portions may be curved in the cross-section of the U-shaped member 4.
In the end bending step, ends of the U-shaped member 4 are bent by press forming using a third die 50 and a fourth die 55, and beads 42A are formed in the gradually-reduced-width portion 42 of the U-shaped member 4 (see
The third die 50 has a bottom 51, a projection 52, two frame portions 53, and two bead-forming portions 54.
The projection 52 is a portion having a cross-section curved in a U-shape, protruding from a center of the bottom 51 in width directions thereof. The width directions are directions that are orthogonal to the axis A directions and are orthogonal to directions in which the third die 50 and the fourth die 55 come to face each other during end bending.
The two frame portions 53 are each located on a corresponding one of both end sides of the bottom 51 in the width directions thereof. The two frame portions 53 are adjacent to the projection 52. Formed between inner-circumferential surfaces of the two frame portions 53 and an outer-circumferential surface of the projection 52 are gaps 53A, which the U-shaped member 4 is allowed to enter.
The two bead-forming portions 54 are arranged in parts of the third die 50 that press the gradually-reduced-width portion 42 of the U-shaped member 4. Each of the bead-forming portions 54 is arranged in each of the frame portions 53 in a corresponding manner. Each of the bead-forming portions 54 is arranged extending from the inner-circumferential surface of the corresponding frame portion 53 to the outer-circumferential surface of the projection 52, which faces the aforementioned inner-circumferential surface. The bead-forming portions 54 are portions to form the beads 13 of the pipe 1. In the gaps 53A, a segment in which the bead-forming portions 54 are arranged has a shape corresponding to a shape of the beads 13.
The fourth die 55 has a recess 56 whose shape corresponds to a shape of the projection 52 of the third die 50. The recess 56 has a shape corresponding to a shape of the bottom 47 of the U-shaped member 4.
In the end bending step, the first end portion 43 and the second end portions 45 in the U-shaped member 4 are bent so that the first end 44 and the second end 46 come close to each other (in other words, so that the first end 44 and the second end 46 lean inward). End bending may be performed on the entire U-shaped member 4. Or, end bending may be performed on the gradually-reduced-width portion 42, on a part of the wide width portion 40 in the vicinity of the gradually-reduced-width portion 42, and on a part of the narrow width portion 41 in the vicinity of the gradually-reduced-width portion 42. At the time of bending, the bead 42A is formed in each of the first end portion 43 and the second end portion 45 in the gradually-reduced-width portion 42, extending along the axis A. In one example, the bead 42A in the first end portion 43 is positioned in the vicinity to the first end 44, extending along the first end 44. Similarly, in one example, the bead 42A in the second end portion 45 is positioned in the vicinity to the second end 46, extending along the second end 46.
To be more specific, in the end bending step, the third die 50 and the fourth die 55 are positioned so that the projection 52 and the recess 56 face each other. In one example, the third die 50 is positioned above and the fourth die 55 is positioned below; however, positions of the third die 50 and the fourth die 55 can be determined appropriately.
Then, the U-shaped member 4 is arranged between the third die 50 and the fourth die 55 with the bottom 47 arranged on the recess 56 of the fourth die 55. At this point, the bottom 47 abuts the recess 56, and the first end 44 and the second end 46 of the U-shaped member 4 face the third die 50.
Then, the third die 50 and the fourth die 55 are brought closer to each other, and the projection 52 enters between the first end portion 43 and the second end portion 45 in the U-shaped member 4. At this point, the first end portion 43 and the second end portion 45 each enter a corresponding one of the two gaps 53A, which are formed between each of the frame portions 53 and the projection 52. As a result of this, the first end portion 43 and the second end portion 45 in the U-shaped member 4 are bent so that the first end 44 and the second end 46 come closer to each other, and the bead 42A is formed in each of the first end portion 43 and the second end portion 45 in the gradually-reduced-width portion 42 (see
In the O-shape bending step, by press forming using a fifth die 60 and a sixth die 65, the U-shaped member 4 on which the end bending has been performed is bent into a O-shape (see
In addition, two bead-holding portions 62 are provided in respective parts of the recess 61 of the fifth die 60 that presses the gradually-reduced-width portion 42 of the U-shaped member 4. The bead-holding portions 62 are groove-shaped portions extending along the axis A. Each of the bead-holding portions 62 is provided at positions that are spaced at the substantially equal distance from a center of the recess 61 in width directions of the cross-section of the recess 61.
In the O-shape bending step, the fifth die 60 and the sixth die 65 are positioned so that the recesses 61, 66 come to face each other. In one example, the fifth die 60 is positioned above and the sixth die 65 is positioned below; however, positions of the fifth die 60 and the sixth die 65 can be determined appropriately.
Then, the U-shaped member 4 is arranged between the fifth die 60 and the sixth die 65 with the bottom 47 arranged on the recess 66 of the sixth die 65. At this point, the bottom 47 abuts the recess 66, and the first end 44 and the second end 46 of the U-shaped member 4 face the recess 61 of the fifth die 60.
Then, the fifth die 60 and the sixth die 65 are brought close to each other. By doing so, the recess 61 of the fifth die 60 firstly come to abut the first end 44 and the second end 46 of the U-shaped member 4 and then press these ends. At this time, the beads 42A, which have been formed in the first end portion 43 and the second end portion 45 of the gradually-reduced-width portion 42, come to abut the bead-holding portions 62. Then, while shapes of the beads 42A are held by the bead-holding portions 62, O-shape bending is performed and the U-shaped member 4 is formed into the shape of the pipe 1. At this time, the first end 44 and the second end 46 of the U-shaped member 4 face each other to form the butted portion 14, and the beads 13 are formed on both sides of the butted portion 14.
In the welding step, the butted portion 14 of the pipe 1, which was formed in the O-shape bending step, is welded. In other words, the first end 44 and the second end 46 in the U-shaped member 4 formed into the shape of the pipe 1 are welded. This results in formation of the pipe 1.
(1) In one example, when the pipe 1 having the large-diameter portion 10, the small-diameter portion 11, and the gradually-reduced-diameter portion 12 is used as a vehicle-mounted component, specifically, as an instrument panel reinforcement for example, the large-diameter portion 10 with a larger diameter might be required to increase stiffness. Further, in this case, for the purpose of relaxing requirements for installing other members in a vehicle, the gradually-reduced-diameter portion 12 with a shorter length in the axis A directions might be required. Furthermore, it is considered that shortening the gradually-reduced-diameter portion 12 increases an inclination of the gradually-reduced-diameter portion 12, in other words, shortening the gradually-reduced-diameter portion 12 increases a degree of change in the diameter of the cross-section of the gradually-reduced-diameter portion 12.
Due to the larger diameter of the large-diameter portion 10, an amount of material that moves in the vicinity of the large-diameter portion 10 in the gradually-reduced-diameter portion 12 increases during O-shape bending. In addition, due to the increased inclination of the gradually-reduced-diameter portion 12, the gradually-reduced-diameter portion 12 is susceptible to stress that occurs in the axis A directions during O-shape bending. For these reasons, when the pipe 1 is formed by UO-shape bending, buckling may occur at the gradually-reduced-diameter portion 12 in a relatively initial stage of the O-shape bending step.
In contrast, in the aforementioned embodiment, the beads 42A are formed in the gradually-reduced-width portion 42 of the U-shaped member 4, which is a part corresponding to the gradually-reduced-diameter portion 12, in the step prior to the O-shape bending step. This improves cross-section modulus of the gradually-reduced-width portion 42 (in other words, cross-section modulus of the gradually-reduced-diameter portion 12), and inhibits occurrence of buckling at the gradually-reduced-width portion 42 during O-shape bending. As a result of this, it is possible to try to shorten a lead time in manufacturing the pipe 1.
(2) In addition, the beads 42A are formed in the gradually-reduced-width portion 42 in the end bending step. Thus, the beads 42A can be formed in the U-shape member 4 in a simplified configuration using the third die 50 for end bending.
(3) In addition, the two beads 42A are formed in the gradually-reduced-width portion 42 of the U-shape member 4 so that the two beads 13 are aligned to have the butted portion 14 between them in the gradually-reduced-diameter portion 12 of the pipe 1. This allows the beads 42A to be arranged at a portion where stress is likely to be concentrated in O-shape bending. This makes it possible to inhibit occurrence of buckling in a more favorable manner.
(4) In addition, the beads 42A are formed in the gradually-reduced-width portion 42 of the U-shape member 4 so that beads 13 pass a boundary of the gradually-reduced-diameter portion 12 with the large-diameter portion 10 in the pipe 1 or pass a vicinity of the boundary. This allows the beads 42A to be arranged at the portion where the stress is likely to be concentrated in O-shape bending. This makes it possible to inhibit occurrence of buckling in a more favorable manner.
(5) In addition, in the gradually-reduced-width portion 42 of the U-shape member 4, the beads 42A are each formed in the vicinity of the first end 44 of the first end portion 43 and in the vicinity of the second end 46 of the second end portion 45, extending along the first end 44 or the second end 46, respectively. In other words, in the gradually-reduced-diameter portion 12 of the pipe 1, the beads 13 are formed in the periphery of the butted portion 14 so as to extend along the butted portion 14. This allows the beads 42A to be arranged at the portion where the stress is likely to be concentrated in O-shape bending. This makes it possible to inhibit occurrence of buckling in a more favorable manner.
(6) In addition, it can be difficult in some cases to join other members such as the framework bracket 16 to the gradually-reduced-diameter portion 12 in the pipe 1 that is used as the instrument panel reinforcement for a vehicle. In contrast, the aforementioned embodiment allows the gradually-reduced-diameter portion 12 to be shortened, so that it is possible to expand a part in the pipe 1 where other members can be joined. This results in a possibility of relaxation of the requirements for installing the other members to be joined to the pipe 1 in a vehicle. Specifically, taking the framework bracket 16 as an example, the framework bracket 16 can be mounted in a vehicle in a more linear shape, which can improve stiffness of the framework bracket 16 and vehicle operability accordingly. Further, by making the framework bracket 16 in a more linear shape, weight and cost of the framework bracket 16 can be reduced. Furthermore, its reduced weight can lead to a reduction in fuel costs of a vehicle and to further improvements in the vehicle operability.
(1) In the method of manufacturing the pipe 1 according to the aforementioned embodiment, it is in the end bending step that the beads 42A are formed in the U-shaped member 4 by means of the third die 50. However, a timing for forming the beads 42A is not limited to this step, and can be set appropriately in a step prior to the O-shape bending step.
Specifically, for example, the beads may be formed in the blank material 2 in a step prior to the U-shape bending step, or the beads 42A may be formed in the U-shaped member 4 in the U-shape bending step or between the U-shape bending step and the end bending step. Alternatively, for example, the beads 42A may be formed in the U-shaped member 4 formed in the end bending step by using a die different from the third die 50.
In addition, according to the aforementioned manufacturing method, the beads 42A are each formed in the vicinity of the first end 44 of the first end portion 43 and in the vicinity of the second end 46 of the second end portion 45 in the gradually-reduced-width portion 42 of the U-shaped member 4, extending along the first end 44 or the second end 46, respectively. However, positions where the beads 42A are formed and the number of the beads 42A are not limited by this method, and can be set appropriately.
(2) The pipe 1 according to the aforementioned embodiment is used as the instrument panel reinforcement. However, without being limited to the above, it may be used as a vehicle-mounted component other than the instrument panel reinforcement or as a member that is not mounted in a vehicle. Further, the pipe 1 may have a bent or curved shape, for example.
(3) In the method of manufacturing the pipe 1 according to the aforementioned embodiment, the beads 13 formed in the gradually-reduced-diameter portion 12 may be crushed after the O-shape bending step. In other words, the beads 13 formed in the gradually-reduced-diameter portion 12 may be eliminated by applying a force, such as pressure, to the pipe 1. Specifically, the beads 13 may be crushed before the welding step, or may be crushed after the welding step.
(4) Two or more functions of a single element in the above-described embodiments may be achieved by two or more elements or a single function of a single element may be achieved by two or more elements. The functions of two or more elements may be achieved by a single element or a single function of two or more elements may be achieved by a single element. Part of the configuration in the above-described embodiments may be omitted. Furthermore, at least part of the configuration of the above-described embodiments may be added to or replaced by a configuration of other embodiments.
A method of manufacturing a pipe extending along an axis of the pipe, the method comprising:
The method of manufacturing a pipe according to item 1,
The method of manufacturing a pipe according to item 1 or 2,
The method of manufacturing a pipe according to any one of items 1 through 3,
The method of manufacturing a pipe according to any one of items 1 through 4,
The method of manufacturing a pipe according to any one of items 1 through 5,
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-125513 | Aug 2023 | JP | national |
