JP6991796B2 - Concave groove processing equipment for metal pipes - Google Patents

Description

The present invention relates to a groove processing device for a metal pipe, which forms concave grooves extending in the longitudinal direction of the pipe from the pipe end at a plurality of locations at the end of the metal pipe at intervals in the circumferential direction.

For example, when a square steel pipe column of a steel structure building structure is bolted to the upper and lower beams, generally, a mounting plate with a bolt hole is welded and fixed to the end of the square steel pipe, and this mounting plate is bolted to the beam. Although the structure is to be joined, in that structure, the outer shape of the mounting plate is wider than the outer shape of the square steel pipe, which may cause inconvenience in relation to the surroundings.
Therefore, the end of the square steel pipe is crushed by press working to form a cross-shaped cross section (crushed shaft-shaped part), and a mounting plate with bolt holes having the same shape as the outer shape of the square steel pipe is welded and fixed to the end face. The mounting plate is bolted to the beam (Patent Documents 1 and 2).

Further, in Patent Document 3, the crushing methods of Patent Documents 1 and 2 which are simply crushed by a press require a large pressing force, which makes the equipment larger and heavier, and also has a cross-shaped cross-sectional portion (crushed shaft-shaped portion). ) May cause cracks in the mountain folds and valley folds, so when the end of the square steel pipe is crushed by press working to form a cross-shaped cross section (crushed shaft-shaped part), it is processed. A method of pressing a square steel pipe in a heated state in the range of 450 to 650 ° C. is shown so that cracks do not occur in the portion.

Japanese Patent Application Laid-Open No. 10-292556 Japanese Patent Application Laid-Open No. 11-324225 JP 2001-71070

According to Patent Document 3, by heating at the time of pressing, the problem that a large pressing force is required and the equipment becomes large and heavy, and the problem that cracks may occur are solved, but heating is performed. Since what is required is not advantageous in terms of equipment, workability, etc., it is possible to form a cross section (a cross section with a groove if it is not a cross section) without the need for heating. desired.

The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and when forming a concave groove portion such as a cross-shaped cross section at the end portion of a metal tube, the equipment is increased in size without requiring heating. It is an object of the present invention to provide a groove processing apparatus for a metal pipe, which does not cause a problem of weight increase or a problem of cracking or the like.

The invention according to claim 1 solves the above-mentioned problems. It ’s a device,
On the central axis side, there are four solo van ball-shaped rotating bodies that are thick and taper toward the tip in the radial direction and are arranged in the circumferential direction in a cross-sectional shape with a narrow flat surface or concave surface on the tip surface. , A plurality of rotating body holders that rotatably hold a plurality of solo van ball-shaped rotating bodies arranged in the circumferential direction, and a circumferential position of the outer surface of the metal tube in which the plurality of rotating body holders are to form a concave groove. The rotating body holder is provided with a housing provided corresponding to the above and a reduction adjusting means provided in the housing for adjusting the reduction of the rotating body holder, and the rotating body holder directly receives a load acting on the solo van ball-shaped rotating body. It is characterized by having an oilless metal having a shape, a holder body for accommodating the oilless metal, and a lid for holding the solo van ball-shaped rotating body from coming out.

2. The second aspect of the present invention is the groove processing apparatus for a metal tube according to the first aspect.
A recessed cross-sectional shape portion having a plurality of recesses facing each other at the radial tip side portion of each solo van ball-shaped rotating body at the center position of the circumferential arrangement of the plurality of solo van ball-shaped rotating bodies arranged in the circumferential direction. It is characterized in that a short rod-shaped core extending in the longitudinal direction of the pipe is arranged.
A third aspect of the present invention is a groove processing device for a metal pipe, which forms concave grooves extending in the longitudinal direction of the pipe from the pipe end at four locations at the end of the square metal pipe, which are spaced apart from each other in the circumferential direction.
On the central axis side, there are four abacus ball-shaped rotating bodies that are thick and taper toward the tip in the radial direction and are arranged in the circumferential direction in a cross-sectional shape with a narrow flat surface or concave surface on the tip surface. ,
Four rotating body holders that rotatably hold the four solo van ball-shaped rotating bodies arranged in the circumferential direction, and the circumferential position of the outer surface of the square metal tube in which the four rotating body holders should form a concave groove. The rotating body holder is provided with a housing provided corresponding to the above and a reduction adjusting means provided in the housing for adjusting the reduction of the rotating body holder, and the rotating body holder directly receives a load acting on the solo van ball-shaped rotating body. It is a groove processing device for a metal tube, characterized in that it is provided with an oilless metal having a shape, a holder body for accommodating the oilless metal, and a lid for holding the solo van ball-shaped rotating body from coming out.
The fourth aspect of the present invention is to provide four recesses facing the radial tip side portions of the four solo van ball-shaped rotating bodies at the center positions of the four solo van ball-shaped rotating bodies arranged in the circumferential direction. The recessed groove processing device for a metal tube according to claim 3, wherein a short rod-shaped core having a recessed cross-sectional shape portion extending in the longitudinal direction of the tube is arranged.

According to the concave groove processing apparatus for a metal tube of the present invention, a solo van ball-shaped rotating body having a flat surface or a concave surface having a narrow tip surface and a metal tube to be processed are opposed to each other in the longitudinal direction of the metal tube. It is possible to drive the solo van ball-shaped rotating body and the metal tube relatively close to each other to form a plurality of concave grooves on the outer surface of the end of the metal tube. There is no problem of increasing the size and weight of the metal tube, cracking of the concave groove (valley fold), and no heating is required. It becomes possible to form.
In addition, since the solo van ball-shaped rotating body held in the rotating body holder is directly rotatably supported by OILES metal without having a rotation axis, the device can be made compact while being able to handle a large load. ..

According to claim 2 , processing can be performed in a state where the core is arranged at the center position of the circumferential arrangement of the plurality of abacus ball-shaped rotating bodies arranged in the circumferential direction, and the abacus ball-shaped rotating body outside the tube can be processed. Since it is possible to perform concave groove processing with the core in the pipe, it is possible to form a concave groove having an accurate shape.

According to the concave groove processing device for a metal pipe according to claim 7, the solo van ball-shaped rotating body held in the rotating body holder is directly rotatably supported by OILES metal without having a rotation axis, so that a large load can be applied. The device can be made compact while being compatible.

An embodiment of the concave groove processing device for a metal pipe of the present invention is shown, where (a) is a side view of the concave groove processing device, and (b) is a front view showing the housing with the lid removed in (a). Is. It is an enlarged view which showed only the main part in FIG. 1 enlarged. (A) is an enlarged view showing one rotating body holder in FIG. 2 in a partial cross section, (b) is an enlarged view of the vicinity of the tip surface of the abacus ball-shaped rotating body in (a), and (c) is the tip. It is a figure which shows the other embodiment of the shape of a surface. It is a figure explaining the concave groove processing method by the concave groove processing apparatus of the metal tube of FIG. 1 showing only the abacus ball-shaped rotating body and the metal tube, (a) is a side view, (b) is a front view, (c). ) Is a front view of a metal tube with a concave groove at the end as viewed from the end side. It is a perspective view of a metal tube having a cross-shaped cross-sectional end manufactured by the above-mentioned groove processing apparatus for a metal tube. It is a figure explaining the corner deformation behavior when the corner part of a square steel pipe is pushed in to form a concave groove, and (a) is the figure which pushed the corner part by the solo van ball-shaped rotating body of this invention which has a flat surface at the tip. In the case, (b) is an explanatory view when a corner portion is pushed by a solo van ball-shaped rotating body having an arc surface at the tip, and (c) is a view showing a cross section of a square steel pipe. The processing procedure in the case where two of the above-mentioned metal pipe concave groove processing devices are installed in parallel to form a cross-shaped cross section (cross pipe portion) at both ends of a metal pipe pillar material of a building structure will be described. It is a figure. It is a figure explaining the processing procedure in the case of installing the above-mentioned metal pipe concave groove processing apparatus in series, for example, forming a cross pipe portion at both ends of a metal pipe pillar material of a building structure. It is a figure explaining one use example of the steel pipe column which formed the cross-shaped cross section at both ends of the square steel pipe by the concave groove processing apparatus of the metal pipe of this invention, (a) is a side view, (b) is a plan view. , (C) is a cross-sectional view taken along the line EE. It is an embodiment when the metal pipe is a round pipe and corresponds to FIG. 4, (a) is a side view, (b) is a front view, and (c) is a metal pipe with a concave groove at the end. Is a front view seen from the end side. It is the figure (side view) corresponding to FIG. 1 (a) which shows the concave groove processing apparatus of the metal tube of another Example (the Example which uses a core) of this invention. (A) is a view showing and explaining only the main part of the concave groove processing device for the metal pipe of FIG. 11, and (b) is a side view, and (b) is a cross-sectional view taken along the line AA of (a). (A) and (b) are views showing only the upper and lower abacus ball-shaped rotating bodies and cores in FIGS. 12 (a) and 12 (b), respectively (for the sake of clarity). (B) is a cross-sectional view taken along the line BB of (a). 11 is a perspective view showing the core in FIGS. 11 to 13 alone. A device for processing a groove in a metal tube according to still another embodiment of the present invention (an embodiment using a different core) is shown. FIG. 12 (a) is a diagram corresponding to FIG. 12 (a), and FIG. 12 (b) is a diagram. It is a figure corresponding to (b). (B) is a cross-sectional view taken along the line CC of (a). (A) and (b) are views showing only the upper and lower abacus ball-shaped rotating bodies and cores in FIGS. 15 (a) and 15 (b), respectively (for the sake of clarity). (B) is a cross-sectional view taken along the line DD of (a). (A) is a perspective view showing the core in FIGS. 15 and 16 independently, and (b) is a front view of the core in (a).

Hereinafter, a mode for carrying out the groove processing apparatus for a metal tube of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the concave groove processing device 10 for a metal tube of the present invention, (a) is a side view of the concave groove processing device 10, and (b) is a housing lid removed in (a). 2 is an enlarged view showing only the main part in FIG. 1 (b) in an enlarged manner.
In this embodiment, a cross-shaped cross section is formed at both ends of a rectangular square steel pipe 8 (hereinafter, in the case of a rectangular square steel pipe, simply referred to as a square steel pipe).
The concave groove processing device 10 is provided with four concave groove forming mechanisms 1 in the housing 7 so as to correspond to the four corner portions of the square steel pipe 8 to be processed.
Each concave groove forming mechanism 1 includes a rotating body holder 3 that rotatably holds the abacus ball-shaped rotating body 2 forming the concave groove, and the rotating body holder 3 is moved and adjusted toward the center of the device to adjust the abacus ball-shaped rotating body 2. A reduction adjusting mechanism 11 for adjusting the reduction of the rotating body 2 is provided.
As shown in detail in FIGS. 3 (a) and 3 (b), the abacus ball-shaped rotating body 2 is thick on the central axis side (side of the central axis m) and narrows in a tapered shape toward the tip in the radial direction. It has a cross-sectional shape having a flat surface 2a having a narrow width on its tip surface, and is rotatably held by the rotating body holder 3 as described above. As shown in FIG. 3 (c), the cross-sectional shape may have a concave concave surface 2a'with a narrow width on the tip surface.
The rotating body holder 3 has an OILES metal 4 having a shape that directly receives a load acting on the solo van ball-shaped rotating body 2, a holder main body 5 that houses the oiles metal 4, and a lid that prevents the solo van ball-shaped rotating body from coming off. It has a body 6.
The solo van ball-shaped rotating body 2 does not have a rotation axis, and is slidably directly in direct surface contact with the oiles metal 4, and the load acting on the solo van ball-shaped rotating body 2 is supported by the oiles metal 4 as described above. Will be done.

The housing 7 includes a housing body 7a that slidably accommodates the four rotating body holders 3, an outer lid 7b, and a base portion 7a'that also serves as an inner lid.
The reduction adjustment mechanism 11 has a reduction screw 11a rotatably connected to the upper surface of the rotating body holder 3, an adjustment nut 11b screwed into the reduction screw 11a, and the adjustment nut 11b rotatably attached to the housing body 7a. It includes a nut holding portion 11c for fixing. The reduction can be adjusted by turning the adjusting nut 11b to adjust the position of the rotating body holder 3 (the position of the abacus ball-shaped rotating body 2). However, the reduction adjustment mechanism in the present invention is not limited to the reduction adjustment mechanism 11 of the embodiment, and various mechanisms can be adopted. For example, it can also be adopted by a scroll chuck method or the like. In this case, the reduction adjustment of the plurality of rotating body holders can be performed at the same time.
The housing body 7a of the housing 7 is integrated with the base portion 7a'which also serves as the inner lid, and slidably accommodates the four rotating body holders 3 as described above. The outer lid 7b is fixed to the housing body 7a with bolts.
Although the details of the base portion 7a'of the housing body 7a are omitted, the base portion 7a'is fixed to a rotating face plate 13 rotatably attached to the apparatus stand 12 indicated by the two-dot chain line, and is also attached to the base portion 7a'. A metal tube guide 14 for guiding the metal tube 8 to be processed is fixed.

When a cross-shaped cross section is formed, for example, at the end of a square steel pipe 8 by the above-mentioned concave groove processing device 10, in FIG. When the square steel pipe 8 is pushed into the space surrounded by the four solo van ball-shaped rotating bodies 2 of the concave groove processing device 10, the sizing (forming) process action (or cold roll forming) in the electric resistance pipe production line is performed. By the action), as shown in FIGS. 4 (a), (b), and (c), the four corners of the square steel pipe are crushed by the four solo van ball-shaped rotating bodies 2, and a concave groove 8a is formed in the corners. Ru. Reference numeral 8b is a protruding portion in which the surface portion of the square steel pipe is not crushed and remains in a protruding state. A square steel pipe 8 having four concave grooves 8a formed at its ends is shown in a perspective view in FIG.
When a deep groove 8a is formed as shown in the illustrated example, a cross-shaped cross-sectional portion 8c is formed at the end of the square steel pipe 8.
It is also possible to fix the square steel pipe and drive the concave groove processing device 10 by pushing it toward the end side of the fixed square steel pipe to form a concave groove at the end of the square steel pipe. In short, it suffices if they can be driven relatively close to each other.

When forming a deep groove having a cross-shaped cross section on the outer surface of a square steel pipe, the general idea of the sizing process in an electrosewn steel pipe production line is to taper the width toward the tip in the radial direction as a sizing roll. However, in the present invention, the roll profile is adopted so that the tip surface becomes an arc surface, but in the present invention, the tip surface has a narrow flat surface 2a or concave surface 2a'. This is the shape adopted as a result of the following experiments.
As shown in FIG. 6 (b), in an experiment in which a corner portion of a square steel pipe was pushed in as shown by an arrow with a roll M having an arc convex tip surface, cracks were often generated at the corner portion. Therefore, after considering various causes, as shown in Fig. 6 (a), an experiment was conducted in which the corners were pushed in as shown by the arrows with a roll K whose tip surface was a flat surface (or concave surface), and cracks occurred. No more to do.
The following are considered as the reasons why cracks occur when the corners are pushed by a roll whose tip surface is an arc convex surface.
When forming a round steel pipe into a square steel pipe in the sizing process of the electric resistance pipe production line, a large plastic deformation occurs at the corner of the square steel pipe (the hatched part in FIG. 6 (c)) and it becomes a total plastic region, which is remarkable. Work hardening has occurred. Therefore, as shown in FIG. 6B, when the convex R portion having a convex tip arc surface is pushed in, the convex R portion in a narrow range of the corner portion is pushed in, so that the work-hardened convex R portion in the narrow range of the corner portion is formed. However, cracks are likely to occur due to severe deformation such as bending and deformation into a concave R shape in the opposite direction.
On the other hand, as shown in FIG. 6 (a), when the corner portion is pushed by the roll K whose tip surface is a flat surface (or concave surface), the convex R portion in a narrow range of the corner portion is bent into a concave R shape in the opposite direction. Instead of being deformed, a slightly wide portion including the portions on both sides thereof was pushed in and deformed while maintaining the convex shape of the convex R portion in a narrow range to some extent. Therefore, the deformation of the work-hardened convex R portion in a narrow range is reduced and cracks do not occur.
In FIGS. 6A and 6B, the arc convex roll M is bent and deformed in the order of M1, M2, and M3 and then pushed in, and the roll K on the flat tip surface is pushed in the order of K1, K2, and K3. It is shown that. K1 and M1 indicate the time when the corners are in contact with each other, and K2 and M2 shown by solid lines indicate the time when the corners begin to dent and the difference in deformation behavior between the two is characteristically shown.

When the above-mentioned concave groove processing device 10 is used to manufacture a metal tube having a cross-shaped cross section at both ends of the metal tube, the production efficiency is high if two concave groove processing devices 10 are installed and manufactured. .. In that case, it is efficient to adopt the method of FIG. 7 or FIG.
FIG. 7 shows a case where two concave groove processing devices 10A and 10B are installed in parallel on opposite sides of a metal tube 8 (installed in a staggered manner rather than facing each other). In this case, the pushing devices 20A and 20B by, for example, a hydraulic cylinder are arranged so as to face each other.
In the figure (a), by pushing the metal tube 8 toward the concave groove processing device 10A by the pushing device 20A, a cross-shaped cross-sectional portion 8c is formed at one end as shown in (b).
When the metal pipe is conveyed between the concave groove processing device 10B and the pushing device 20B as shown in (c) and pushed to the concave groove processing device 10B side by the pushing device 20B, it is pushed to the other end as shown in (d). A cross-shaped cross section 8c is formed, whereby a metal tube 8 having a cross-shaped cross section 8c formed at both ends is obtained.

FIG. 8 shows a case where two concave groove processing devices 10A and 10B are manufactured by a series method in which two concave groove processing devices 10A and 10B are installed at opposite positions sandwiching a metal tube 8. In this case, the pushing devices 20A and 20B are arranged behind the concave groove processing devices 10.
In (a) of FIG. 8 [I], the abacus ball-shaped rotating body 2 of the concave groove processing device 10A is kept in an open state, and the pushing portion of the pushing device 20A is passed through the concave groove processing device 10A in the open state. By pushing the metal tube 8 toward the concave groove processing device 10B, a cross-shaped cross-sectional portion 8c is formed at one end as shown in (b).
Next, as shown in (c) of FIG. 8 [II], the solo van ball-shaped rotating body 2 of the concave groove processing device 10B is kept in an open state, and the indented portion of the indentation device 20B is in an open state. By passing the device 10B and pushing the metal tube 8 toward the concave groove processing device 10A, a cross-shaped cross section 8c is formed at the other end as shown in (d), thereby forming a cross-shaped cross section 8c at both ends. The metal tube 8 is obtained .
In the case of the series method of FIG. 8, the metal pipe 8 may be fixed and the concave groove processing device 10 may be pushed into the metal pipe side by the pushing device 20. In that case, the cross-shaped cross-section portion 8c is naturally formed at the end portion on the opposite side of the cross-shaped cross-section portion 8c shown in FIG. 8 (the end portion on the pushed-in concave groove processing device 10 side). Become.

When a square steel pipe having a cross-shaped cross-section 8c formed at both ends is used as a pillar material of a building structure, a mounting plate for bolt joining with a beam material is welded and fixed to the end surface of the square steel pipe pillar material 8.
FIG. 9 shows only the lower part of the pillar material. For example, a square mounting plate 16 having the same vertical and horizontal dimensions as the square steel pipe is welded and fixed to the lower end surface of the cross-shaped cross section 8c of the square steel pipe pillar material 8. In the illustrated example, it is placed on the lower H-shaped steel beam 17, and the mounting plate 16 and the flange of the H-shaped steel beam 17 are joined by a bolt 18.
Since there are spaces on all four sides of the cross-section portion 8c, the bolts 18 can be used to fix the cross-shaped cross sections, and the sides of the square steel pipe and the flanges of the beams can be joined to the beam in a parallel state.
The same applies to the joint with the upper beam. However, it is natural that a cross-shaped cross section is formed only in the lower part or only in the upper part.
The pillars joined in this way are also excellent in aesthetic appearance as pillars, and are therefore suitable as pillar materials for building structures.
When the side of the square steel pipe is crushed to form a cross-shaped cross section at the end of the pipe, the protruding part becomes the corner of the square steel pipe, and two of the spaces in the four sides of the cross-shaped cross section are H. It will come to the position of the web of the shaped steel beam 17, and it will not be possible to bolt it to the H-shaped steel beam 17 so that it will be aesthetically pleasing as a pillar. Therefore, especially when it is used as a pillar material of a building structure and the beam is H-shaped steel, it is possible to push (crush) the corner portion of the square steel pipe to form a cross-shaped cross section as in the embodiment. You will need it.
However, except when it is used as a pillar material of a building structure and the beam is H-shaped steel as described above, even if the side portion of the square steel pipe is pushed in (crushed) to form a cross-shaped cross section. good. For example, it can be applied to, for example, a pile material for civil engineering, a pile material for a fence, and various other uses, and is particularly suitable for a pile material for civil engineering, a pile material for a fence, and the like.

Although the quadrangular metal tube has been described in the above-described embodiment, it can also be applied to a case where a polygonal metal tube such as a pentagon or a hexagon is targeted.
In that case, instead of the four solo van ball-shaped rotating bodies 2, the rotating body holder 3 and the reduction adjustment mechanism 11 in the above-mentioned concave groove processing device 10, the number of solo van ball-shaped rotating bodies 2 corresponding to the number of corners -By providing the rotating body holder 3 and the reduction adjustment mechanism 11, it is possible to form a concave groove according to the number of corners at the end of the polygonal metal tube. The metal tube guide 14 is adapted to the cross-sectional shape of the polygonal metal tube.

When the metal tube is a round tube and a cross-shaped cross section is formed at the end portion, the concave groove processing device 10 itself may be the same as that shown in FIG. However, the metal tube guide 14 is adapted to the cross-sectional shape of the round tube.
FIG. 10 shows an embodiment when the metal tube is a round tube 18. FIG. 4 is a view corresponding to FIG. 4, (a) is a side view, (b) is a front view, and (c) is a front view of a metal tube having a concave groove at the end as viewed from the end side. .. The concave groove portion is indicated by 18a, the protruding portion is indicated by 18b, and the cross-sectional portion is indicated by 18c.
The manufacturing method is basically the same as that of the square tube, but the position in the circumferential direction to be pushed by the abacus ball-shaped rotating body 2 is not particularly limited.

11 to 14 show a groove processing device 10'for a metal tube according to another embodiment of the present invention . The target metal pipe is a square steel pipe as in the first embodiment of this embodiment.
FIG. 11 is a side view of the concave groove processing device 10'of the embodiment and is a view corresponding to FIG. 1 (a). 12 (a) is a view showing and explaining only the main part of the concave groove processing apparatus 10'of FIG. 11, (a) is a side view, and (b) is a cross-sectional view taken along the line AA of (a). Is. FIG. 13 is a diagram for making each part in FIG. 12 easy to understand, and the illustration of the metal tube 8 in FIG. 12 is omitted, and the left and right two of the four abacus ball-shaped rotating bodies 2 (FIG. 12 (FIG. 12). It is the figure which omitted the illustration of the abacus ball-shaped rotating body 2 of b) left and right two).

The concave groove processing device 10'of this embodiment is located at the center position of the four solo van ball-shaped rotating bodies 2 arranged in the circumferential direction of the outer surface of the metal pipe as shown in FIG. 12 (b). ), A short rod-shaped core 30 extending in the longitudinal direction of the pipe is arranged. That is, not only the above-mentioned abacus ball-shaped rotating body 2 that pushes the outer surface of the metal tube from the outside, but also the core 30 that receives the portion pushed by the abacus ball-shaped rotating body 2 of the metal tube during processing is located in the metal tube. It is arranged like this.

As shown in the perspective view of FIG. 14, the core 30 has four recesses 30a facing each other on the radial tip side portions of the abacus ball-shaped rotating bodies 2, and protrudes between the adjacent recesses 30a. It has a portion 30b and has a cross section. That is, the entire longitudinal direction has a cross section.
A core having a uniform cross section as a whole, such as the core 30, is referred to as a straight caliber core.
In FIG. 14, the horizontal portion and the vertical portion of the core 30 in the cross section are shown in a horizontal and vertical posture.
As shown in FIG. 11, the core 30 is attached to the housing body 7a via the frame body 32. That is, for example, a rectangular plate-shaped core base 31 is integrally fixed to the end surface of the core 30 when viewed from the longitudinal direction of the core, and the core base 31 is attached to the front surface of the housing body 7a in the housing 7. By fixing it to 32 with a bolt, it is fixed to the housing body 7a in a horizontal state.
The lid body 7b'of the housing body 7a in this embodiment is cut out at the upper and lower ends to shorten the length, and the upper and lower portions of the frame body 32 are fixed to the upper and lower parts of the housing body 7a. ..
In FIGS. 11 to 13, basically the same parts as those in FIGS. 1, 2 and 4 are designated by the same reference numerals and the description thereof is omitted.

When a cross-shaped cross section is formed at the end of a square steel pipe 8 by the above-mentioned concave groove processing device 10', for example, as in the first embodiment, as shown by an arrow in FIG. 11 by a pushing device using, for example, a hydraulic cylinder (not shown). When the square steel pipe 8 is pushed into the space surrounded by the four solo van ball-shaped rotating bodies 2 of the concave groove processing device 10'from the left side, the sizing (forming) process action (or cold) in the electrosewn steel pipe production line is performed. As shown in FIGS. 12 (a) and 12 (b), the four corners of the square steel pipe are crushed by the four solo van ball-shaped rotating bodies 2 and the core 30 in the pipe due to the roll forming action). A concave groove 8a is formed in the portion, and the central portion of each surface of the square steel pipe is not crushed and remains in a protruding state to form a protruding portion 8b, resulting in a cross section. The square steel pipe 8 in which the four concave grooves 8a are formed at the ends basically has the shape shown in the perspective view in FIG. 5, but the presence of the core 30 provides an accurate cross-sectional portion 8c. It is formed.

15 to 17 show the main parts of the concave groove processing device 10 ”of the metal pipe of still another embodiment of the present invention . In this embodiment as well, the target metal pipe is a square steel pipe as in the third embodiment. be.
15 (a) is a diagram corresponding to FIG. 12, and is a diagram for explaining the concave groove processing device 10 "by showing only the main part thereof, (a) is a side view, and (b) is C of (a). -C is a cross-sectional view taken along the arrow C. FIG. 16 is a diagram for making each part in FIG. 15 easy to understand, the metal tube 8 in FIG. 15 is not shown, and the four abacus ball-shaped rotating bodies 2 are shown. It is the figure which omitted the illustration of the abacus ball-shaped rotating body 2 of the left and right two (two on the left and right of FIG. 15 (b)).

Similar to the third embodiment, the concave groove processing device 10 "of this embodiment extends in the longitudinal direction of the pipe at the center position of the four solo van ball-shaped rotating bodies 2 arranged in the circumferential direction of the outer surface of the metal pipe. A short rod-shaped core 40 is arranged.
As shown in FIG. 17, the core 40 has four recessed portions 40a facing each other on the radial tip side portion of each solo van ball-shaped rotating body 2, and a protruding portion 40b is provided between the adjacent recessed portions 40a. It has a cross-section portion 40c forming a cross shape, but has a cross-sectional shape portion 40d in the pipe along the inner surface of the square pipe, not a cross-section portion in the entire longitudinal direction. Further, it has a curved transition concave surface 40e that smoothly connects from the corner portion of the in-pipe cross-sectional shape portion 40d to the straight concave portion 40a in the longitudinal direction along the radial tip side shape of the abacus ball-shaped rotating body 2. ..
A core 40 having such an in-pipe cross-sectional shape portion 40d, a curved transition concave surface 40e, and a cross-sectional cross-sectional portion 40c is called a total caliber core.
In FIG. 17, the horizontal portion and the vertical portion of the cross section of the core 40 are shown in a horizontal and vertical posture.

This Example 4 is basically different in that the core 40 is a total caliber core, but the core 40 has an in-pipe cross-sectional shape portion 40d and a curved transition concave surface 40e, so that the abacus ball The recessed portion 40a is smoothly formed by the shape rotating body 2 and the core 40, and it becomes easy to secure the shape accuracy.
In FIGS. 15 to 17, basically the same parts as those in FIGS. 11 to 14 are designated by the same reference numerals and the description thereof is omitted.

1 Concave groove forming mechanism 2 Solovan ball-shaped rotating body 2a Flat surface 2a'Concave surface 3 Rotating body holder m Central axis 4 Oiles metal 5 Holder body 6 Cover body 7 Housing 7a Housing body 7a'(inside the housing body) Base part 7b , 7b'Cover (of housing) Octagonal steel pipe (metal pipe)
18 Round steel pipe (metal pipe)
8a, 18a concave groove (concave groove part)
8b, 18b Protruding part 8c, 18c Cross-shaped cross section 10, 10'10 "Metal tube concave groove processing device 11 Reduction adjustment mechanism 11a Reduction adjustment screw 11b Adjustment nut 11c Nut holding part 12 Device stand 13 Rotating face plate 14 Metal tube Guide 16 Mounting plate 20 Pushing device 30 Core (straight caliber core)
40 core (total caliber core)
30a, 40a Recessed portion 30b, 40b Protruding portion 40c Cross-sectional portion 40d In-pipe cross-sectional shape portion 40e Curved transition concave surface 31 Core base 32 Frame body

Claims (4)

It is a groove processing device for a metal pipe that forms concave grooves extending in the longitudinal direction of the pipe from the pipe end at a plurality of places spaced in the circumferential direction of the outer surface at the end of the metal pipe.
With a plurality of abacus ball-shaped rotating bodies arranged in the circumferential direction in a cross-sectional shape having a flat surface or a concave surface having a narrow flat surface or a concave surface on the tip surface, which is wide and narrows in a taper shape toward the tip in the radial direction on the central axis side. ,
A plurality of rotating body holders that rotatably hold a plurality of solo van ball-shaped rotating bodies arranged in the circumferential direction, and the plurality of rotating body holders at positions in the circumferential direction of the outer surface of the metal tube to which a concave groove should be formed. A housing provided correspondingly and a reduction adjusting means provided in the housing for adjusting the reduction of the rotating body holder are provided, and the rotating body holder has a shape that directly receives a load acting on the solo van ball-shaped rotating body. A groove processing device for a metal tube, which comprises an oilless metal, a holder body for accommodating the oilless metal, and a lid for holding the solo van ball-shaped rotating body from coming out. At the center position of the circumferential arrangement of the plurality of solo van ball-shaped rotating bodies arranged in the circumferential direction, a recessed cross-sectional shape portion having a plurality of recessed portions facing the radial tip side portions of the respective solo van ball-shaped rotating bodies is provided. The concave groove processing apparatus for a metal pipe according to claim 1, wherein a short rod-shaped core extending in the longitudinal direction of the pipe is arranged. It is a groove processing device for a metal pipe that forms concave grooves extending in the longitudinal direction of the pipe from the pipe end at four places spaced in the circumferential direction of the outer surface at the end of the quadrangular metal pipe.
On the central axis side, there are four abacus ball-shaped rotating bodies that are thick and taper toward the tip in the radial direction and are arranged in the circumferential direction in a cross-sectional shape with a narrow flat surface or concave surface on the tip surface. ,
Four rotating body holders that rotatably hold the four solo van ball-shaped rotating bodies arranged in the circumferential direction, and the circumferential position of the outer surface of the square metal tube in which the four rotating body holders should form a concave groove. The rotating body holder is provided with a housing provided corresponding to the above and a reduction adjusting means provided in the housing for adjusting the reduction of the rotating body holder, and the rotating body holder directly receives a load acting on the solo van ball-shaped rotating body. A groove processing device for a metal tube, which comprises an oilless metal having a shape, a holder body for accommodating the oilless metal, and a lid for holding the solo van ball-shaped rotating body from coming out. A recessed cross-sectional shape portion having four recesses facing each other at the radial tip side portion of each solo van ball-shaped rotating body at the center position of the circumferential arrangement of the four solo van ball-shaped rotating bodies arranged in the circumferential direction. The concave groove processing apparatus for a metal pipe according to claim 3, wherein a short rod-shaped core extending in the longitudinal direction of the pipe is arranged.

Images