JP6831251B2 - Manufacturing method of tubular member - Google Patents

Description

The present disclosure relates to a method for manufacturing a tubular member.

It is known that a tubular member such as an outer shell member of a muffler of a vehicle is manufactured by joining a plurality of edges of a metal plate curved in a tubular shape by welding. Further, Patent Document 1 discloses that when manufacturing such a tubular member, a metal plate is curved into a tubular shape so that two edges overlap each other, and the overlapping portions are welded. ..

Japanese Unexamined Patent Publication No. 11-324637

However, when the above-mentioned welding is performed, the temperature of the portion of the metal plate including the welded portion becomes high. Therefore, the hot portion may be deformed and residual stress may be generated in the portion. As a result, when the welded tubular metal plate is formed into another shape, for example, buckling may occur. That is, molding of the tubular metal plate may be difficult.

In the process of manufacturing the tubular member, it is desirable to facilitate the molding of the tubular member.

In the method of manufacturing a tubular member, which is one aspect of the present disclosure, one or more metal plates are arranged in a tubular shape extending in a predetermined extension direction. At this time, the arranged one or a plurality of metal plates are in a state in which the plurality of edges thereof extend along the extending direction. Further, a tubular member is generated by joining a plurality of edges of one or a plurality of arranged metal plates by welding. Then, the portion of the tubular member including the welded edges is pressed.

According to such a configuration, the residual stress generated in the tubular member by welding is removed by pressing the portion of the tubular member including the welded portion. Therefore, when the tubular member is formed into another shape, for example, buckling can be suppressed. Therefore, in the process of manufacturing the tubular member, molding of the tubular member becomes easy.

The cross section of one or a plurality of plates arranged in a tubular shape that is orthogonal to the extension direction may have a predetermined first shape. Then, by pressing the portion of the tubular member including the welded edges, the shape of the cross section of the tubular member may be prompted to become the first shape.

According to such a configuration, the shape of the tubular member after welding is urged to return to the shape before welding. Therefore, it becomes easy to mold the tubular member into another shape.
Further, the one or more metal plates arranged in a tubular shape may extend linearly.

With such a configuration, it becomes easy to form a tubular member extending linearly.
Further, the first shape may be circular or substantially circular.
With such a configuration, molding of a cylindrical member becomes easy.

Further, the welding may be performed using at least a part of seam welding, spot welding, arc welding, plasma welding, and TIG welding.
When welding is performed by these welding methods, it is considered that the tubular member tends to have a high temperature. That is, a large amount of residual stress may be generated in the tubular member after welding. Therefore, it is possible to effectively remove the residual stress by pressing the portion of the tubular member including the welded portion.

Further, the portion of the tubular member including the plurality of welded edges may be pressed by rolling the rotating body along the plurality of edges.
According to such a configuration, the portion of the tubular member including the welded portion can be effectively pressed.

Further, the tubular member may be mounted on the vehicle.
With such a configuration, molding of a tubular member mounted on a vehicle becomes easy.
Further, by pressing the side surface of the tubular member from the outside, the cross-sectional shape of the tubular member may be changed to a second shape extending in a predetermined direction. Further, an internal mold that abuts on the inner surface of the tubular member is inserted into the inside of the tubular member that is pressed so that the cross section has the second shape, and the internal mold is inserted from one end to the other end of the tubular member. You may slide up to. Then, in the internal mold, when sliding from one end to the other end of the tubular member, one or a plurality of contact regions where the inner surface of the tubular member and the internal mold come into contact with each other go around the inner surface. It may be configured to be.

When the pressing of the tubular member pressed so that the cross section has the second shape is released, the tubular member may be deformed due to the springback. On the other hand, according to the above configuration, a load is applied to the inner surface of the tubular member being pressed by sliding the inner surface with the inner mold. As a result, it is possible to prevent the tubular member from being deformed by the springback when the pressing of the tubular member is released. Therefore, molding of the tubular member becomes easy.

Further, the internal type may have a plurality of divided portions. The plurality of divided portions are configured so that one or a plurality of contact regions are formed by the outer surface of each divided portion, and each divided portion has a position relative to the other one or a plurality of divided portions. It may be configured to be adjustable.

According to such a configuration, the position of the outer surface of each divided portion can be adjusted, whereby the position of one or more contact regions that abut on the inner surface of the tubular member in the internal mold can be adjusted. Therefore, for example, even if the shape of the outer surface of the divided portion is deformed due to wear, one or a plurality of contact regions are formed in the internal mold by adjusting the position of the outer surface of the divided portion. Can be maintained.

FIG. 1A is a perspective view of a muffler, and FIG. 1B is a perspective view of a first tubular member according to the present embodiment. 1C and 1D are explanatory views showing an end portion of a metal plate arranged in a tubular shape in the arrangement step in the present embodiment. FIG. 1E is an explanatory view showing an end portion of the second tubular member after welding in the present embodiment. FIG. 2A is an explanatory view showing how the second tubular member is pressed by the rotating body and the lower member in the pressing step of the present embodiment. FIG. 2B is an enlarged explanatory view of a portion of the second tubular member pressed by the rotating body and the lower member in the pressing step of the present embodiment. FIG. 2C is an explanatory view showing how the second tubular member is pressed in the molding step of the present embodiment. 3A is a front view of the internal mold used for the passing step of the present embodiment, FIGS. 3B and 3C are side views of the internal mold, and FIGS. 3D and 3E are top views of the internal mold. .. FIG. 4 is an explanatory view showing how the inner surface of the third tubular member is slid by the internal mold in the passing step of the present embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The embodiments of the present disclosure are not limited to the following embodiments, and various embodiments may be adopted as long as they belong to the technical scope of the present disclosure.

[Explanation of manufacturing method]
In the manufacturing method of the present embodiment, a tubular member that extends linearly in a predetermined extension direction is manufactured. The tubular member has a longitudinal shape in which a cross section orthogonal to the extension direction (hereinafter, simply referred to as a cross section) extends in the longitudinal direction. More specifically, the longitudinal shape means a shape in which the length in the longitudinal direction is longer than the length in the lateral direction. The lateral direction means a direction orthogonal to the longitudinal direction. Specifically, the longitudinal shape may be, for example, an elliptical shape, a rectangular shape, or the like. Further, the tubular member is made of a metal such as stainless steel.

In the manufacturing method, as an example, as shown in FIG. 1A, the side surface portion 11 of the outer shell member 10 of the muffler 1 of the vehicle is manufactured. The outer shell member 10 is a plate-shaped member that separates the inside and the outside of the muffler 1. The outer shell member 10 has two bottom surface portions 12 and side surface portions 11. Each bottom surface portion 12 has a longitudinal shape. Further, the side surface portion 11 is a tubular member having the above-mentioned cross section having a longitudinal shape (more specifically, an elliptical shape).

In addition, the tubular member used for various purposes may be manufactured by the manufacturing method of the present embodiment. Specifically, for example, a pipe or a tubular member included in a housing for accommodating a predetermined device may be manufactured. Further, these members may be mounted on the vehicle.

The manufacturing method of the present embodiment includes a placement step, a welding step, a pressing step, a molding step, and a passing step.
In the arrangement step, one or more metal plates 2 are arranged in the shape of the first tubular member 20 shown in FIG. 1B. The first tubular member 20 extends linearly in the extension direction 20a. Further, the first tubular member 20 has a constant thickness. That is, the size and shape of the cross section of the first tubular member 20 are constant. Here, the shape of the cross section of the first tubular member 20 is taken as the original shape. The original shape is, for example, circular or substantially circular. That is, the first tubular member 20 has a cylindrical shape. The original shape may be a shape other than a circle or a substantially circular shape. Specifically, the original shape may be, for example, a polygonal shape. Further, the first tubular member 20 may be a tubular member extending in a non-linear manner. In other words, the first tubular member 20 may extend along, for example, a curved or bent path.

Then, the edge portions 2a and 2b of the one or a plurality of metal plates 2 arranged in the shape of the first tubular member 20 are in a state of extending along the extension direction 20a. Further, the edge portions 2a and 2b are in a state of extending from one end to the other end of the first tubular member 20 as an example.

More specifically, in the arrangement step, as an example, as shown in FIGS. 1C and 1D, one rectangular metal plate 2 is curved into a tubular shape so that the metal plate 2 has the shape of the first tubular member 20. It may be molded into. Further, the two edge portions 2a and 2b forming the two facing sides of the metal plate 2 may be in an overlapping state. Hereinafter, the portion where these edge portions 2a and 2b overlap is referred to as an overlapping portion 2c.

Further, as shown in FIG. 1C, the metal plates 2 formed in the shape of the first tubular member 20 may be arranged in a single layer. Further, as shown in FIG. 1D, the metal plates 2 may be arranged in a doubly overlapped state. Further, the metal plates 2 may be arranged in a state of being overlapped in three or more layers.

In addition to this, in the arrangement step, for example, a plurality of metal plates curved in a groove shape may be arranged in a state of forming the shape of the first tubular member 20. Even in such a case, each metal plate may be similarly arranged so that an overlapping portion overlapping the edge portion of another metal plate is provided at the edge portion thereof.

Next, in the welding step, a plurality of facing edge portions 2a, 2b in one or a plurality of metal plates 2 having the shape of the first tubular member 20 are welded along the plurality of edge portions 2a, 2b. .. Specifically, the overlapping portion 2c, which is a portion where the plurality of edge portions 2a and 2b overlap, is welded. As a result, the plurality of edge portions 2a and 2b are joined to generate the second tubular member 21.

More specifically, the portions of the overlapping portion 2c located on both the outer side and the inner side of the first tubular member 20 or one of them may be welded. Further, for example, the overlapping portion 2c may be welded by any one of seam welding, spot welding, arc welding, plasma welding, and tig welding. Further, the overlapping portion 2c may be welded by using a plurality of these welding methods in combination. Further, the overlapping portion 2c may be welded by one or a plurality of welding methods including seam welding.

Here, due to welding, the portion of the second tubular member 21 including the overlapping portion 2c becomes hot. Therefore, residual stress is generated in the portion of the second tubular member 21 including the overlapping portion 2c. Further, for this reason, the cross-sectional shape of the second tubular member 21 is different from the original shape. Specifically, for example, when the original shape is circular or substantially circular, as shown in FIG. 1E, the cross section of the second tubular member 21 loses the roundness of the overlapping portion 2c and the portions on both sides thereof.

Therefore, in the subsequent pressing step, the portion of the second tubular member 21 including the overlapping portion 2c (hereinafter referred to as the pressing target portion) is pressed. The pressing target portion may include a portion of the second tubular member 21 that is presumed to have residual stress. Further, the pressing target portion may include a portion of the second tubular member 21 that has been deformed by welding. At this time, the pressing target portion is sandwiched by two members from the inside and the outside of the second tubular member 21. As an example, as shown in FIGS. 2A and 2B, the pressing target portion is pressed by the rotating body 30 and the lower member 31.

The lower member 31 is an elongated member extending in the longitudinal direction and has a lower contact region 31a. The lower contact region 31a is provided on the upper outer surface of the lower member 31. Further, the lower contact region 31a is a strip-shaped region extending linearly in the longitudinal direction and having a constant or substantially constant width.

Further, the lower contact region 31a is curved so that the center in the width direction protrudes. That is, the portion corresponding to the lower contact region 31a in the cross section orthogonal to the longitudinal direction of the lower member 31 is arcuate. Further, the lower member 31 is configured so that the portion has the same shape from one end to the other end. Further, the degree of curvature of the portion may be the same as or substantially the same as the degree of curvature of the overlapping section at the outer edge of the cross section of the first tubular member 20. The overlapping section is a section including a portion of the outer edge of the cross section where the overlapping portion 2c is located.

Further, the lower member 31 is arranged inside the second tubular member 21. At this time, the lower member 31 is located below the pressing target portion and extends from one end to the other end of the pressing target portion. Further, the lower contact region 31a is in a state of facing the pressing target portion. At this time, the lower contact region 31a may be in contact with all or part of the pressing target portion.

On the other hand, the rotating body 30 is a columnar member extending linearly in the longitudinal direction. The side surface of the rotating body 30 is curved so that the center in the longitudinal direction is deeply recessed. That is, the diameter of the circle forming the cross section orthogonal to the longitudinal direction in the rotating body 30 is the shortest at the center in the longitudinal direction and becomes longer toward the end in the longitudinal direction.

Here, the region including the center in the longitudinal direction on the side surface of the rotating body 30 is referred to as the upper contact region 30a. The portion of the rotating body 30 corresponding to the upper contact region 30a in the cross section including the center line is arcuate. The degree of curvature of the portion is the same as or substantially the same as the degree of curvature of the overlapping section described above.

Then, the rotating body 30 presses the pressing target portion of the second tubular member 21 arranged on the lower member 31 from the outside of the second tubular member 21. At this time, the upper contact region 30a of the rotating body 30 is in contact with the pressing target portion from the outside of the second tubular member 21. Further, at this time, the pressing target portion is in a state of being sandwiched between the upper contact region 30a of the rotating body 30 and the lower contact region 31a of the lower member 31. Then, the rotating body 30 rolls on the pressing target portion from one end to the other end of the second tubular member 21 while pressing the pressing target portion.

Further, as described above, the degree of curvature of the upper contact region 30a and the lower contact region 31a is the same as or substantially the same as the degree of curvature of the overlapping section described above. Therefore, by pressing with the rotating body 30, the degree of curvature of the pressed target portion in the second tubular member 21 is the degree of curvature of the overlapping section described above (in other words, the degree of curvature of the outer edge of the original shape). Is prompted to be the same or substantially the same. That is, the shape of the cross section of the second tubular member 21 is urged to be the original shape.

In addition to this, the pressing target portion of the second tubular member 21 may be pressed by a member other than the rotating body 30. Specifically, for example, the pressing target portion may be pressed by sandwiching the pressing target portion of the second tubular member 21 once or a plurality of times between the upper member and the lower member (not shown). Here, the region of each of the upper member and the lower member that abuts on the pressing target portion is defined as a contact region. By adjusting the shape of the contact region, pressing by the upper member and the lower member may similarly prompt the shape of the cross section of the second tubular member 21 to be the original shape. Further, even if the pressing target portion is pressed by the rotating body 30 and the lower member 31, or the upper member and the lower member, without prompting the shape of the cross section of the second tubular member 21 to return to the original shape. good. Further, in the pressing step, pressing may be prompted so that the shape of the cross section of the second tubular member 21 becomes a shape other than the original shape.

Next, in the molding step, the second tubular member 21 is molded so that the cross section has the above-mentioned longitudinal shape by pressing the second tubular member 21 from the outside. In other words, the longitudinal shape is a shape longer than the original shape.

As shown in FIG. 2C, in the molding step, as an example, the first external mold 40 and the second external mold 41 are arranged vertically side by side. Further, the second tubular member 21 is arranged on the second external mold 41 located on the lower side. Then, the second tubular member 21 is pressed by moving the first external mold 40 downward and sandwiching the second tubular member 21 between the first external mold 40 and the second external mold 41. As a result, the cross section of the second tubular member 21 becomes a longitudinal shape. Hereinafter, the second tubular member 21 having a long cross section will be referred to as a third tubular member 22.

Here, in the third tubular member 22, the two portions extending along the longitudinal direction are referred to as the longitudinal portion 22a. Further, in the third tubular member 22, the two portions located at the end portions in the longitudinal direction are referred to as the short portion 22b. In other words, the longitudinal portion 22a is a portion of the third tubular member 22 where the degree of extension due to the pressing of the molding step reaches a certain level. In the third tubular member 22, the overlapping portion 2c is located at the longitudinal portion 22a as an example. More specifically, the overlapping portion 2c is located at the end of the upper longitudinal portion 22a. The overlapping portion 2c may be located on the short portion 22b. That is, in the molding step, in the stage before pressing, the overlapping portion of the second tubular member 21 arranged on the second outer mold 41 so that the overlapping portion 2c is arranged at a predetermined position when pressed. The position of 2c is adjusted.

However, the third tubular member 22 is made of metal. Therefore, if the first external mold 40 is moved upward to release the pressing after the pressing in the molding step, springback may occur in the third tubular member 22. That is, the third tubular member 22 whose pressure has been released may be curved so that, for example, the longitudinal portion 22a bulges outward due to the elastic recovery.

Therefore, in the subsequent passing step, the internal mold 50 shown in FIGS. 3A to 3E is inserted into the inside of the third tubular member 22 pressed by the first and second external molds 40 and 41. The inner mold 50 is configured such that a part of its outer surface abuts on the inner surface of the third tubular member 22. One or more contact regions where the outer surface of the inner mold 50 and the inner surface of the third tubular member 22 abut are in a state of circling the inner surface (hereinafter, a contact state).

More specifically, a path that goes around the outer surface of the internal mold 50 is defined as a circuit path. The circumferential path is in a state in which the entire circumference extends along the outer edge of the cross section of the third tubular member 22 into which the internal mold 50 is inserted. One or more contact areas are arranged along the orbital path. That is, in the entire section of the circuit path, at least one contact region 50d exists on the circuit path and / or on the side of the circuit path.

Then, in the passing step, as shown in FIG. 4, the internal mold 50 is moved from one end to the other end of the third tubular member 22 while maintaining the contact state. More specifically, the internal mold 50 is inserted into the inside of the third tubular member 22 from one end of the third tubular member 22. The internal mold 50 is moved to the other end of the third tubular member 22, and then moved to one end of the third tubular member 22. Due to these movements, the inner surface of the third tubular member 22 is slid by the internal mold 50.

As shown in FIGS. 3A to 3D, the internal mold 50 has two divided portions 51 and 52 as an example. Each divided portion is an elongated portion extending in the longitudinal direction 50a. One split portion 51 is attached to one end of the rod-shaped portion 55. The rod-shaped portion 55 is used to move the internal mold 50 in the passing step.

Further, the two divided portions 51 and 52 are connected by a plurality of screws 56 and the like. The internal mold 50 is configured as a combination of these divided portions 51 and 52. At this time, the outer surfaces of the divided portions are in contact with each other. Then, when the plurality of screws 56 are loosened, each divided portion can adjust the position relative to the other divided portions. Specifically, at this time, each divided portion can be moved in the longitudinal direction 50a as an example. Then, when the plurality of screws 56 are tightened, the positions of the divided portions are fixed.

Here, the outer edge when the two joined split portions 51, 52 (in other words, the inner mold 50) is viewed in the lateral direction 50b is referred to as the contact outer edge 50c. The contact outer edge 50c includes the above-mentioned orbital path. The two divided portions 51 and 52 are configured such that the contact outer edge 50c has the same or substantially the same shape as the cross section of the third tubular member 22. When the inner mold 50 is in the contact state, a contact region 50d that contacts the inner surface of the third tubular member 22 is provided along the contact outer edge 50c. The contact region 50d is in a state where it goes around the inner surface of the third tubular member 22.

The two divided portions 51 and 52 may be connected with a gap. In this case, the outer surface of the inner mold 50 is provided with two separated contact regions along the circumferential path.
Further, by changing the relative position of each divided portion, the size and shape of the contact outer edge 50c (in other words, the size and shape of the circumferential path) can be changed. As a result, the size and shape of the contact region 50d change.

The internal mold may be composed of one part. Then, a similar contact region may be provided on the outer surface of the internal mold.
Further, the internal mold may be composed of three or more divided portions. That is, as shown in FIG. 3E, the internal mold 50 may have three divided portions 51 to 53 as an example. Each divided portion is an elongated portion extending in the longitudinal direction 50a. Further, the split portion 53 is attached to one end of the rod-shaped portion 55. Then, even in such a case, the contact region 50d may be provided on the outer surface of the internal mold 50 in the same manner. Further, each of the two divided portions 51 and 52 may be connected to the divided portion 53 by a plurality of screws 56, and the relative positions of the divided portions may be adjusted in the same manner. Further, each divided portion may be connected with a gap in the same manner.

[effect]
(1) According to the above embodiment, the pressed target portion of the second tubular member 21 pressed in the pressing step includes a welded portion. As a result, the residual stress generated in the second tubular member 21 by welding is removed. Therefore, when the second tubular member 21 is formed into another shape, for example, buckling can be suppressed. Therefore, in the process of manufacturing the tubular member, molding of the tubular member becomes easy.

(2) Further, in the pressing step, the second tubular member 21 is urged to have the original shape in cross section. Therefore, it becomes easy to mold the second tubular member 21 into another shape.
(3) Further, in the arrangement step, one or a plurality of metal plates 2 are arranged in a state of forming the shape of the first tubular member 20. Then, the first tubular member 20 extends linearly along the extension direction 20a. Therefore, it becomes easy to form a tubular member that extends linearly.

(4) Further, the cross section of the first tubular member 20 is circular or substantially circular. Therefore, molding of a cylindrical member becomes easy.
(5) Further, in the welding step, welding of one or more metal plates 2 is performed using at least a part of seam welding, spot welding, arc welding, plasma welding, and TIG welding.

When welding is performed by these welding methods, it is considered that one or more metal plates 2 tend to have a high temperature. That is, there is a possibility that more residual stress will be generated in the second tubular member 21 generated by welding. Therefore, the residual stress can be effectively removed by pressing in the pressing step.

(6) Further, in the pressing step, the pressing target portion of the second tubular member 21 is pressed by rolling the rotating body 30. As a result, the portion of the second tubular member 21 including the welded portion can be effectively pressed.

(7) Further, in the manufacturing method of the above embodiment, a tubular member to be mounted on a vehicle, such as a side surface portion 11 of the outer shell member 10 of the muffler 1, is manufactured. Therefore, it becomes easy to mold the tubular member mounted on the vehicle.

(8) Further, in the passing step, a load is applied to the inner surface by sliding the inner surface of the third tubular member 22 pressed to make the cross section into a longitudinal shape by the inner mold 50. As a result, it is possible to prevent the third tubular member 22 from being deformed by the springback when the pressing of the third tubular member 22 is released. Therefore, molding of the tubular member becomes easy.

(9) Further, the internal mold 50 is configured as a combination of a plurality of divided portions 51 and 52. Then, each divided portion can adjust the position relative to the other divided portions.
Therefore, the position of the outer surface of each divided portion can be adjusted, whereby the position of one or a plurality of contact regions where the internal mold 50 abuts on the inner surface of the third tubular member 22 is adjusted. Therefore, for example, even if the shape of the outer surface of the divided portion is deformed due to wear, one or more contact regions are formed on the internal mold 50 by adjusting the position of the outer surface of the divided portion. Can be maintained. Further, the internal mold 50 can be used for sliding the inner surfaces of tubular members having various shapes in the same manner.

[Other Embodiments]
(1) In the above embodiment, the first to third tubular members 20 to 22 have a constant cross-sectional size and shape. However, the first to third tubular members 20 to 22 may have a shape in which the size and / or shape of the cross section is not constant. Then, in the passing step, the internal mold 50 may be moved from one end to the other end of the third tubular member 22 while maintaining the above-mentioned contact state by changing the orientation of the internal mold, for example. ..

(2) In the molding step of the above embodiment, the second tubular member 21 is molded into the third tubular member 22 having a longitudinal cross section. However, the second tubular member 21 may be formed into another shape. Specifically, the second tubular member 21 may be formed into, for example, a tubular member having a polygonal cross section, or may be formed into a curved or bent tubular member. Further, the second tubular member 21 may be formed so that, for example, the overlapping portion 2c extends in a direction intersecting the extension direction 20a (for example, in an orthogonal or substantially orthogonal direction).

(3) The function of one component in the above embodiment may be shared by a plurality of components, or the function of the plurality of components may be exerted by one component. In addition, a part of the configuration of the above embodiment may be omitted as long as the problem can be solved. It should be noted that all aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

[Correspondence with claims]
The original shape in the present embodiment corresponds to an example of the first shape, and the longitudinal shape corresponds to an example of the second shape.

2 ... Metal plate, 2a, 2b ... Edge part, 2c ... Overlapping part, 11 ... Side part, 20 ... First tubular member, 21 ... Second tubular member, 22 ... Third tubular member, 30 ... Rotating body , 30a ... Upper contact area, 31 ... Lower member, 31a ... Lower contact area, 40 ... First external type, 41 ... Second external type, 50 ... Internal type, 51-53 ... Divided portion.

Claims (7)

It is a manufacturing method of tubular members.
One or more metal plates are arranged in a tubular shape extending in a predetermined extension direction.
The arranged one or more metal plates are in a state in which the plurality of edges thereof extend along the extension direction.
By joining the plurality of edges of the arranged one or more metal plates by welding, the tubular member is generated.
Pressing the welded portion of the tubular member, including the plurality of edges,
The cross section of the one or more plates arranged in a tubular shape orthogonal to the extension direction is a predetermined first shape.
By rolling the rotating body along the plurality of welded edges of the tubular member, a portion including the plurality of edges is arranged on the side surface of the rotating body and inside the tubular member. The lower member is pressed so as to be sandwiched between the lower member and the lower contact area, thereby prompting the shape of the cross section of the tubular member to be the first shape.
The side surface of the rotating body and the lower contact area of the lower member form a curve corresponding to the first shape.
The lower contact area extends from one end to the other end of the tubular member .
By pressing the side surface of the tubular member from the outside, the shape of the cross section of the tubular member is made into a second shape extending in a predetermined direction.
An internal mold that abuts on the inner surface of the tubular member is inserted into the inside of the tubular member whose cross section is pressed so as to have the second shape, and the internal mold is inserted from one end of the tubular member. Slide to the other end
The internal mold is in a state in which one or a plurality of contact regions where the inner surface of the tubular member and the internal mold abut when sliding from one end to the other end of the tubular member circles the inner surface. A method for manufacturing a tubular member that is configured to be . In the method for manufacturing a tubular member according to claim 1 ,
The internal mold has a plurality of divided portions and has a plurality of divided portions.
The plurality of divided portions are configured such that the one or a plurality of contact regions are formed by the outer surface of each divided portion, and each divided portion has a position relative to the other one or a plurality of divided portions. A method of manufacturing a tubular member that is configured to be adjustable. In the method for manufacturing a tubular member according to claim 1 or 2 .
A method for manufacturing a tubular member in which the one or more metal plates arranged in a tubular shape extend linearly along the extension direction. In the method for manufacturing a tubular member according to any one of claims 1 to 3 .
The first shape is a method for manufacturing a tubular member that is circular or substantially circular. In the method for manufacturing a tubular member according to any one of claims 1 to 4 .
The welding is a method for manufacturing a tubular member, which is performed by using at least a part of seam welding, spot welding, arc welding, plasma welding, and TIG welding. In the method for manufacturing a tubular member according to any one of claims 1 to 5 .
The tubular member is a method for manufacturing a tubular member to be mounted on a vehicle. It is a manufacturing method of tubular members.
One or more metal plates are arranged in a tubular shape extending in a predetermined extension direction.
The arranged one or more metal plates are in a state in which the plurality of edges thereof extend along the extension direction.
By joining the plurality of edges of the arranged one or more metal plates by welding, the tubular member is generated.
Pressing the welded portion of the tubular member, including the plurality of edges,
By pressing the side surface of the tubular member from the outside, the shape of the cross section of the tubular member orthogonal to the extension direction is changed to a second shape extending in a predetermined direction.
An internal mold that abuts on the inner surface of the tubular member is inserted into the inside of the tubular member whose cross section is pressed so as to have the second shape, and the internal mold is inserted from one end of the tubular member. Slide to the other end
The internal mold is in a state in which one or a plurality of contact regions where the inner surface of the tubular member and the internal mold abut when sliding from one end to the other end of the tubular member circles the inner surface. A method for manufacturing a tubular member that is configured to be.

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