JP2016002579A - Recessed groove forming method of metal pipe surface, recessed groove forming apparatus, and metal pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recessed groove forming method of a metal pipe surface, a recessed groove forming apparatus, and a metal pipe, which are suitable for the production of a roof rail body of a roof rail for an automobile, which can prevent the wear or deterioration of a pattern thereby to maintain an initial pattern for a long period of time, and which intensify the strength of a metal pipe thereby to improve a lifetime.SOLUTION: A core grid 4 having a section substantially identical to that of a metal pipe 1 is inserted thereinto; a shaping roll 8 having one or more shaped salients 9 formed on a rotatable pressing face is rotated and moved in the axial direction of the metal pipe 1 so that the shaped salients are pressed onto the surface of the metal pipe thereby to form recesses 2.

Description

  The present invention is suitable, for example, for manufacturing a roof rail body of an automobile roof rail, and without forming a synthetic resin coating or an expensive and large-scale equipment on the surface of the metal tube, a concave groove is directly formed on the surface of the metal tube. Produces patterns with concave grooves easily and inexpensively, improves the aesthetics and design of the surface of the metal tube, realizes the production of patterns according to the concept of the car, and prevents the pattern from wearing or deteriorating. The present invention relates to a method for forming a groove on the surface of a metal tube, a groove forming device, and a metal tube that can maintain the strength of the metal tube for a long period of time and can enhance the strength of the metal tube and improve the life.

  Conventional roof rails for automobiles are formed by extruding an aluminum tube with a deformed cross section to form a roof rail body, bending it further in a three-dimensional direction, and forming it by adding other processing when forming it. In general, since special processing and decoration are not performed on the molding surface, there is a problem that the appearance is generally lacking in aesthetics or design (see, for example, Patent Document 1).

As an example of such a roof rail body that has been appropriately molded, there is one in which a concave surface having an arc groove shape is formed in the length direction of an inner wall (see, for example, Patent Document 2).
However, since the concave surface is continuously formed over both end portions of the inner wall in manufacturing, its structure is monotonous and has no design features, and there is a limit to adopting this as a decorative pattern. It was.

  In order to solve such problems, a stainless steel plate is roll-formed, a rail is formed on a tubular body having an irregular cross section, a thermoplastic resin is coated on the outer surface of the rail, and a glass fiber is coated on the thermoplastic resin material. In addition to reinforcing the strength of the covering portion by adding a material, the outer surface portion of the covering portion is formed in a texture pattern with a glass fiber material to improve the appearance of the roof rail body (for example, Patent Documents) 3).

  However, since the roof rail for automobiles is formed by rolling a stainless steel plate and the surface of the rail is coated with a thermoplastic resin, the manufacturing process is complicated and labor-intensive. There was a problem of becoming expensive.

Therefore, in order to solve such problems, the roof rail body is formed by extruding a metal tube such as an aluminum tube, eliminating the design coating process on the surface of the metal tube, and forming a groove-like pattern on the surface of the metal tube. A direct forming method can be considered.
Conventionally, a roll molding method or a press molding method has been adopted as a method corresponding to such a molding or processing method.

  Among these, as a roll forming method corresponding to the above problem solving, a thin metal tube is attached to a cylindrical rotating body so as to be movable, and a pressure roll driven by the thin metal tube is provided as a thin metal tube. An uneven mother pattern is formed on the pressing surface of the pressure roll, the pressing surface is pressed against the surface of the thin metal tube, and the mother pattern is formed. Is formed by pressing on the surface of a thin metal tube (for example, see Patent Document 4).

  However, this roll forming method requires the formation of a mother pattern in the pressurizing roll and moves the pressurizing roll in the axial direction of the thin metal tube. However, it is limited to a uniform circular tube, and it cannot be used for thin metal pipes with irregular shapes. Moreover, a transfer pattern with a mother pattern is formed in a spiral pattern on the thin metal pipe. There is a problem that it is not limited to the formation of various patterns.

  As another roll forming method in response to the above problem solving, in the manufacturing process of the plastic coated steel pipe, the molten plastic is coated on the steel pipe, and after cooling the coated plastic, the pair of crimping rolls are separated and rotated. The crimping roll is formed in a drum shape, and a plurality of cylindrical protrusions are arranged on its peripheral surface, and the molten coated plastic is cooled to 60 to 150 ° C., which is completely cured. There is one in which a pressing roll is pressed before to form a large number of irregularities on the entire area of the plastic coating (for example, see Patent Document 5).

  However, this roll forming method requires plastic coating and cooling, requires complicated equipment, requires expensive and large-scale equipment, and the formed irregularities are shallow, low in strength, generally short in life, and have a short life. There was a problem that irregularities could not be formed on the surface.

  Further, as another roll forming method in response to the above problem solving, a drum-shaped roller is rotatably provided immediately above a metal pipe coated with an acrylic resin paint, and a curved surface of the roller is made of urethane rubber. The coating is applied to the surface of the metal pipe, and the roller rotates and pressurizes the roller while it is not dried to move in the axial direction. In some cases, a wood grain pattern having a grid or the like is formed (for example, see Patent Document 6).

  However, this roll forming method forms an uneven wood grain pattern on the paint applied to the surface of the metal pipe, which requires application of the paint to the surface of the metal pipe, which is troublesome and expensive. Since the pattern was not formed on the pipe surface itself, there was a problem that it was not possible to directly respond to the problem.

  Furthermore, as another roll forming method in response to the above problem solving, the metal strip of a thick stainless steel plate having a concavo-convex pattern on the surface is bent into a tubular shape, the joints at both ends thereof are welded, and the concavo-convex pattern is formed on the surface. There is one in which a metal tube is formed (see, for example, Patent Document 6).

  However, in this roll forming method, a metal strip is rolled using a rolling mill to form a concavo-convex pattern, then bent by a forming roll, and the joining end portion thereof is TIG welded to form a tubular shape. There is a problem that a large-scale and expensive facility is required and the molding becomes large.

  On the other hand, as a press molding method corresponding to the above problem solving, a substantially semicircular molding groove is formed on the inner surface of a pair of upper and lower molding dies that are gently curved, and a plurality of convex beads are protruded from the molding groove. An elbow-shaped curved pipe is accommodated in the forming groove, and a plurality of annular grooves are formed on the peripheral surface of the curved pipe by the convex bead (for example, see Patent Document 7).

  However, in the press molding method, the formation of the concave groove is limited to the annular groove, and a plurality of concave grooves cannot be formed in the axial direction, and the pattern on the circumferential surface of the curved pipe is limited. There was a problem that it was not possible.

Japanese Patent No. 4397361 JP 11-49031 A JP-A-9-226467 JP 2013-244671 A JP-A-62-267132 Japanese Patent No. 3713572 JP 2009-82933 A JP 2005-81393 A

  The present invention solves such a problem, and is suitable for manufacturing a roof rail body of, for example, an automobile roof rail. The surface of the metal pipe is not required to be coated with a synthetic resin or expensive and large-scale equipment. Grooves are directly formed to easily and inexpensively create patterns with grooves, improve the appearance and design of the surface of metal pipes, and create patterns according to the concept of automobiles, as well as wear and alteration of patterns. It is possible to provide a concave groove forming method, a concave groove forming apparatus, and a metal tube on the surface of a metal tube, which can maintain the initial pattern for a long period of time and can enhance the strength of the metal tube and improve the life. Objective.

  According to the first aspect of the present invention, one or a plurality of forming convex portions are provided on a pressing surface of a rotatable forming roll or a forming groove of a forming mold capable of moving up and down, and the forming roll is rotated to form a metal tube. In the method of forming a groove on the surface of the metal tube, the metal tube is moved in the axial direction of the metal mold, or the upper mold of the molding die is moved up and down to form a groove by pressing the molding convex portion on the surface of the metal tube. A metal core having substantially the same cross section as the metal tube is inserted into the metal tube to support the metal tube, and the molding convex portion is directly pressed against the surface of the metal tube directly above the metal core or the metal tube surface on the lower mold. Without forming a synthetic resin coating or expensive and large-scale equipment on the surface of the metal tube by directly forming a concave groove on the surface of the tube, for example, a metal tube is inserted by inserting a metal core into a metal tube formed by extruding aluminum. Supports, prevents deformation of the metal tube and realizes direct forming of the groove, making the pattern by the groove easy It can be manufactured at low cost, improving the aesthetics and design of the surface of the metal tube, creating patterns according to the product concept, and preventing the wear and alteration of the pattern by directly forming the metal tube itself. The initial pattern can be maintained over a long period of time, and the strength of the metal tube is enhanced to improve the service life.

According to the second aspect of the present invention, the pressing amount of the upper die of the forming roll or the molding die with respect to the entire or partial region in the axial direction of the metal tube is maintained constant, and the concave grooves in the entire or partial region of the metal tube are maintained. The depth is formed at a constant value, and a pattern formed by a groove in a certain region is formed at a constant value, thereby forming a stable and uniform pattern.
According to a third aspect of the present invention, the pressing amount of the upper die of the forming roll or the molding die for the plurality of areas in the axial direction of the metal tube is adjusted, and the depth of the groove in the plurality of areas is made different from each other. Various patterns with concave grooves are formed in the area, and the design and aesthetics of the metal tube are improved by the arrangement of the pattern and the gradation of the pattern visually.
In the invention of claim 4, the pressing amount of the upper die of the forming roll or the molding die with respect to the entire axial direction of the metal tube is gradually increased or decreased from one end to the other end, and the depth of the concave grooves is changed from one end to the other. It is gradually increased or decreased over the end, and a gradation of visual shading is formed from one end of the metal tube to the other end, thereby improving the design and aesthetics of the metal tube.

The invention of claim 5 uses a metal core having a smooth pressure-receiving surface when forming a shallow groove, and forming a groove on the pressure-receiving surface that accommodates a pressing projection of a metal tube when forming a deep groove. The cored bar is used, and the cored bar is selectively used according to the depth of the concave groove, and the cored bar after the concave groove is formed can be taken out smoothly and easily.
The invention of claim 6 inserts the metal cores from both sides of the metal tube, abuts the inner end portions thereof, holds the outer end portions immovable, and inserts the metal cores reasonably and quickly. In addition, the outer end portions thereof are prevented from swinging, and the concave grooves can be formed stably and accurately. The invention of claim 7 is configured such that the metal tube is formed of an aluminum extrusion molding material, and the molding convex portion is used. Pressing can be performed easily and smoothly.

  The invention according to claim 8 is characterized in that one or a plurality of molding convex portions are provided on the pressing surface of the rotatable molding roll or the molding groove of the molding die movable up and down, and the molding roll is rotated in the axial direction of the metal tube. In the groove forming apparatus on the surface of the metal tube, the metal tube is provided so as to be movable or by moving the upper mold of the molding die up and down and pressing the molding convex portion on the surface of the metal tube so that the groove can be formed. A metal core having substantially the same cross section as that of the metal tube is provided so as to be inserted, and the metal tube is supported through the metal core, and a convex portion is formed on the surface of the metal tube directly above the metal core or on the surface of the metal tube on the lower mold. Can be directly pressed, the groove can be directly pressed on the surface of the metal tube, the metal tube is supported by the metal core, and the metal tube can be directly molded by the molding convex part. Eliminate the complicated process of forming the coating and its concave groove, forming the metal tube surface easily and inexpensively In addition to improving the aesthetics and design of the product, it is possible to produce patterns according to the product concept and to prevent the wear and alteration of the pattern by directly forming the metal tube itself, maintaining the original pattern for a long time At the same time, the strength of the metal tube is strengthened to improve the service life.

According to the ninth aspect of the present invention, a plurality of molding convex portions are arranged on the pressing surface of the molding roll or the molding groove of the molding die so that various pattern forming of the concave grooves by the molding convex portions can be realized on the surface of the metal tube. ing.
In the invention of claim 10, the pressing amount of the upper die of the forming roll or the molding die can be adjusted in the whole or part of the axial direction of the metal tube, and the depth of the groove in the plurality of regions is made different from each other. Various shapes of grooves are formed, and the design and aesthetics of the metal tube are improved by the arrangement of the patterns and the visual gradation of the patterns.
According to the invention of claim 11, the pressing amount of the upper die of the molding roll or the molding die can be gradually increased or decreased from one end of the metal tube to the other end, and the depth of the concave grooves is changed from one end to the other end. It gradually increases or decreases over time, and a gradation of visual shading is formed from one end of the metal tube to the other end, thereby improving the design and aesthetics of the metal tube.
According to the invention of claim 12, the cored bar has a pressure receiving surface formed smoothly, or a concave groove capable of accommodating a pressing convex portion of a metal tube is continuously formed on the pressure receiving surface in the axial direction of the peripheral surface. Depending on whether it is shallow or deep, the metal cores are used differently and each metal core can be easily removed.

The invention of claim 13 presses one or a plurality of concave grooves on the surface via one or a plurality of molding convex portions provided on a pressing surface of a rotatable molding roll or a molding groove of a molding die capable of moving up and down. In the formed metal tube, the molding convex part is directly pressed on the surface to form the concave groove directly, thereby forming various patterns by the concave groove on the surface of the metal pipe, and the aesthetics and design of the metal pipe surface are realized. We can improve and provide a metal tube with a pattern according to the product concept, and by directly forming the metal tube itself, we can prevent the pattern from being worn or altered and maintain the original pattern over a long period of time. In addition, the strength of the metal tube is enhanced by the concave groove to improve the life.
In the invention of claim 14, the formation area and the non-formation area of the groove are formed in the axial direction of the surface, and the presence / absence area of the pattern by the groove is arranged to improve the design and the aesthetic appearance.
In the invention of claim 15, a plurality of types of concave grooves having different molding depths are formed in the axial direction of the surface, and various patterns are formed by the concave grooves in a plurality of areas. The design and aesthetics of the metal tube are improved by gradation of light and shade.

According to the invention of claim 16, a plurality of concave grooves whose forming depth is gradually increased or gradually decreased from one end to the other end in the axial direction of the surface is formed, and the concave groove pattern is formed from one end to the other end of the metal tube. Visual gradations are formed to improve the design and aesthetics of the metal tube.
According to a seventeenth aspect of the present invention, the metal tube is made of an aluminum extrusion molding material, and the concave groove can be easily and smoothly formed by a flexible molding material.
According to the invention of claim 18, the metal tube is a roof rail body of an automobile rufle, and the aluminum tube is formed by extruding aluminum without requiring a synthetic resin coating or expensive and large-scale equipment on the roof rail body. By forming the groove directly on the surface of the roof, the pattern by the groove can be easily and inexpensively manufactured, the aesthetics and design of the roof rail body can be improved, and the roof rail with the pattern according to the concept of the car can be manufactured. The strength of the roof rail body is strengthened to improve the service life.

According to the first aspect of the present invention, a cored bar having a substantially the same cross section as the metal tube is inserted into the metal tube to support the metal tube, and on the surface of the metal tube directly above the cored bar or the surface of the metal tube on the lower mold. Pressing the convex part directly and forming the groove directly on the surface of the metal tube, so that the surface of the metal tube does not require synthetic resin coating or expensive and large-scale equipment, for example, extruding aluminum into the metal tube A metal core is inserted into the metal tube to support the metal tube, and the metal tube is prevented from being deformed to directly form the groove, and the pattern by the groove is easily and inexpensively manufactured. In addition to improving the design and realizing the production of patterns according to the product concept, the metal tube itself can be directly molded to prevent the pattern from being worn or altered, and the original pattern can be maintained over a long period of time. Enhance strength and improve service life Door can be.
According to the second aspect of the present invention, the pressing amount of the upper die of the forming roll or the molding die with respect to the entire or partial area in the axial direction of the metal tube is maintained constant, and the depression in the entire or partial area of the metal tube is maintained. Since the depth of the groove is formed to be constant, it is possible to form a pattern with a recessed groove in a certain range, and to form a stable and uniform pattern.

The invention of claim 3 adjusts the pressing amount of the upper die of the molding roll or the molding die for the plurality of areas in the axial direction of the metal tube, and makes the depths of the concave grooves in the plurality of areas different from each other. The design and aesthetics of the metal tube can be improved by forming various patterns with concave grooves in a plurality of areas and arranging the pattern and the gradation of the pattern visually.
The invention according to claim 4 gradually increases or decreases the pressing amount of the upper die of the forming roll or the molding die with respect to the entire axial direction of the metal tube from one end to the other end, and sets the depth of the concave grooves to one end. Since it gradually increases or decreases from the other end to the other end, it is possible to form a visual gradation gradation from one end of the metal tube to the other end, thereby improving the design and aesthetics of the metal tube. .

The invention of claim 5 uses a metal core having a smooth pressure-receiving surface when forming a shallow groove, and forming a groove on the pressure-receiving surface that accommodates a pressing projection of a metal tube when forming a deep groove. Since the cored bar is used, the cored bar is properly used according to the depth of the concave groove, and the cored bar after the concave groove is formed can be taken out smoothly and easily.
The invention of claim 6 inserts the metal cores from both sides of the metal tube, abuts the inner end portions thereof, holds the outer end portions immovable, and inserts the metal cores reasonably and quickly. In addition, it is possible to prevent the outer end portions from swinging and to form the concave groove stably and accurately.
According to the seventh aspect of the present invention, since the metal tube is made of an aluminum extrusion molding material, the pressing by the forming convex portion can be performed easily and smoothly.

According to the eighth aspect of the present invention, a cored bar having a substantially the same cross section as the metal tube is provided in the metal tube so as to be inserted, and the metal tube is supported via the cored bar. Since the molding convex part is provided on the upper surface of the metal tube so that it can be pressed directly, and the concave groove can be pressed directly on the surface of the metal pipe, the metal pipe is supported by the core metal, and the metal pipe is directly molded by the molding convex part. It eliminates the conventional process of synthetic resin coating and concave groove forming, and easily and inexpensively molds it to improve the aesthetics and design of the surface of the metal tube, and the pattern according to the product concept In addition to preventing the pattern from being worn or altered by directly forming the metal tube itself, the original pattern can be maintained over a long period of time, and the strength of the metal tube can be strengthened. Improvements can be made.
According to the ninth aspect of the present invention, since a plurality of molding convex portions are arranged on the pressing surface of the molding roll or the molding groove of the molding die, various pattern forming of the concave grooves by the molding convex portions can be realized on the surface of the metal tube. it can

In the invention of claim 10, since the pressing amount of the upper die of the molding roll or the molding die can be adjusted in the entire or partial region in the axial direction of the metal tube, the depth of the concave grooves in the plurality of regions can be adjusted to each other. The design and aesthetics of the metal tube can be improved by forming various patterns by the concave grooves and visually grading the pattern arrangement and the pattern gradation.
In the invention of claim 11, since the pressing amount of the upper die of the molding roll or molding die can be gradually increased or gradually decreased from one end of the metal tube to the other end, the depth of the concave grooves is changed from one end to the other. It can be gradually increased or decreased across the end, and a visual gradation gradation can be formed from one end of the metal tube to the other end, thereby improving the design and aesthetics of the metal tube.
In the invention of claim 12, the cored bar has a concave pressure receiving surface, or a concave groove capable of accommodating the pressing convex portion of the metal tube is continuously formed in the pressure receiving surface in the axial direction of the circumferential surface. Depending on whether the groove is shallow or deep, the cored bar can be used properly and each cored bar can be easily taken out.

In the invention of claim 13, since the concave groove is directly formed by directly pressing the molding convex portion on the surface, various shapes can be formed on the metal pipe surface by the concave groove, and the aesthetic appearance of the metal pipe surface is achieved. Metal pipes with patterns according to the product concept can be manufactured by improving the design, and by directly forming the metal pipes themselves, the wear and alteration of the patterns can be prevented and the original patterns can be maintained over a long period of time. In addition, the strength of the metal tube can be enhanced by the groove and the life can be improved. The invention according to claim 14 is formed by forming the groove forming region and the non-forming region in the axial direction of the surface. The presence or absence of the pattern can be arranged to improve the design and aesthetics.
In the invention of claim 15, since a plurality of types of concave grooves having different molding depths are formed in the axial direction of the surface, various patterns are formed by the concave grooves in a plurality of areas, and the arrangement of the patterns and the visual of the patterns are formed. The light and shaded gradation can improve the design and aesthetics of the metal tube.

According to the sixteenth aspect of the present invention, since the plurality of concave grooves having the forming depth gradually increased or gradually decreased from one end to the other end in the axial direction of the surface, the pattern of the concave grooves from one end to the other end of the metal tube is formed. By forming a visual gradation of gradation, it is possible to improve the design and aesthetics of the metal tube.
According to the seventeenth aspect of the present invention, since the metal tube is formed of an aluminum extrusion molding material, the concave groove can be easily and smoothly formed by the flexible molding material.
In the invention of claim 18, since the metal tube is a roof rail body of a roof rail for automobiles, the surface of the metal tube formed by extruding aluminum is not required on the roof rail body without covering with synthetic resin or expensive and large-scale equipment. By forming the groove directly, the pattern by the groove can be easily and inexpensively manufactured, the aesthetics and design of the roof rail body can be improved, and the roof rail with the pattern according to the concept of the car can be manufactured, and the strength of the roof rail body It is possible to enhance the service life and improve the service life.

(A) is a perspective view showing an example of a roof rail main body in which a shallow concave groove is formed on the surface of a metal tube to which the present invention is applied, and a core metal inserted into the roof rail main body, and (b) is a bottom portion of the roof rail main body. It is a perspective view which shows a side surface. (A) is an expanded sectional view which follows the AA line of Fig.1 (a), (b) is an expanded sectional view which follows the BB line of Fig.1 (a). BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows in order the outline | summary of the pattern formation process by the ditch | groove of the metal tube surface to which this invention is applied, (a) shows the condition which has set the metal tube on the work table, (b) shows a core to a metal tube. A state in which gold is inserted is shown, (c) shows a state of forming the concave groove by the forming roll, and (d) shows a state of taking out the core bar after forming the concave groove.

(A) is sectional drawing of the principal part which shows the condition where the shaping | molding convex part is pressed on the surface of a roof rail main body by the shaping | molding roll applied to this invention, and the ditch | groove is shape | molded. (B) is an enlarged view of the (circle) part of (a). It is a perspective view which shows an example of the roof rail main body which shape | molded the deep groove | channel on the metal tube surface to which this invention is applied, and the core metal inserted in this ruler main body. (A) is an expanded sectional view which follows the CC line of FIG. (B) is an expanded sectional view which follows the DD line of FIG.

It is explanatory drawing which shows the 2nd Embodiment of this invention, and shows the principal part of the other form of the ditch | groove shaping | molding by a shaping | molding roll, (a) shows the pattern by a ditch | groove in the fixed area of the both ends of a metal pipe. The non-molding area of the pattern by the concave groove is formed in the middle area. (B) has shown the condition where the clear pattern is shape | molded in the fixed area of the both ends of a metal tube, and the pale pattern by a concave groove is shape | molded in the intermediate | middle area. (C) shows a situation in which a light pattern due to the groove is formed in a certain area at both ends of the metal tube, and a clear pattern due to the groove is formed in the intermediate area. (D) forms a pattern with concave grooves over the entire area of the metal tube, forms a light pattern at one end, gradually reveals the pattern from one end, forms a gradation, and forms a clear pattern at the other end. Shows the situation.

It is explanatory drawing which shows the 3rd Embodiment of this invention, and shows the pattern formation condition by a ditch | groove on the surface of a metal tube using the shaping die of a press machine, (a) presses a shaping | molding convex part on the surface of a metal tube. Then, a cross-sectional view showing a situation in which a concave groove is formed, (b) is a perspective view showing a ruler main body and a metal core which are metal tubes at that time. It is explanatory drawing which shows the 4th Embodiment of this invention, and shows the pattern formation condition by a ditch | groove on the surface of a metal pipe using the shaping die of a press machine, (a) presses a shaping | molding convex part on the surface of a metal pipe. Then, a perspective view showing a situation in which a concave groove is formed, (b) is a perspective view showing a ruler main body and a metal core which are metal tubes at that time.

It is explanatory drawing which shows the 5th Embodiment of this invention, (a) is the condition which presses a shaping | molding convex part on the surface of a cylindrical metal pipe using the shaping die of a press machine, and is forming the ditch | groove. (B) is a perspective view which shows the ruhr frame main body and cored bar in that case. It is explanatory drawing which shows the 6th Embodiment of this invention, (a) presses a shaping | molding convex part on the surface of a cylindrical metal tube using the shaping die of a press machine, and is forming the ditch | groove. The perspective view which shows a condition, (b) is a perspective view which shows the ruler main body which is a metal tube in that case, and a metal core. It is a perspective view which shows the 7th Embodiment of this invention, (a)-(d) is the perspective view which shows the condition which shape | molded the various pattern by a concave groove on the surface of a metal tube, EE line, F- The expanded sectional view which follows F line, GG line, and HH line is shown.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention applied to a roof rail body of an automobile roof rail will be described below. In FIGS. 1 to 6, reference numeral 1 denotes a roof rail body having a substantially trapezoidal cross section, which is a metal pipe to be processed. A plurality of shallow grooves 2 are formed on the substantially curved peripheral surface 1a which is a part of the surface of the straight curved surface and substantially the entire side surface and bottom surface other than the curved peripheral surface 1a. They are arranged in a double row staggered shape or a double row parallel shape at a constant pitch along the direction.
The concave groove 2 is formed away from or from the end of the roof rail body 1, thereby forming the curved peripheral surface 1 a in a dotted pattern. In the embodiment, the concave groove 2 is formed along the axial direction. Are arranged in a double-row staggered pattern at a constant pitch.

The concave groove 2 is formed in the same shape of an elongated ellipse or a leaf of a tree, and a minute pressing convex portion (not shown) projects from the inner surface of the roof rail body 1.
In this case, the concave groove 2 is not limited to the above-mentioned shape, and various shapes such as a circle, a rectangle, a heart shape, a diamond shape and the like can be selected. It is also possible to arrange them in a composite manner.
Further, the arrangement of the concave grooves 2 is not limited to the double-row staggered pattern or the parallel type, and various arrangements are possible. Further, the pattern by the concave grooves 2 is not limited to the scattered pattern, and may be one or more as shown in FIG. It is also possible to form a plurality of concave grooves 2 in the form of a long straight line and form a linear pattern in which the grooves are arranged in the axial direction at intervals.

  Such pattern formation for the roof rail body 1 is produced by the pattern forming apparatus X shown in FIG. The pattern forming apparatus X includes a solid work table 3 on which a roof rail body 1 of a metal tube, which is a pattern forming object, can be placed, a steel core 4 inserted into the roof rail body 1, and the core An actuator (not shown) such as a pressure cylinder or a rack for inserting and removing 4 into and from the roof rail body 1 and a forming roll 8 for forming the concave groove 2 on the surface of the roof rail body 1 are provided.

  The work table 3 has an engagement surface 3a that can be engaged with the peripheral surface of the roof rail body 1, and the roof rail body 1 can be installed along the engagement surface 3a. A pair of stoppers (not shown) are installed in the length direction to prevent the roof rail body 1 from swinging during molding by a molding roll described later.

The core metal 4 is formed to have a similar cross section that is slightly smaller than the cross section of the roof rail main body 1, and the length thereof is ½ of the length of the roof rail main body 1. In the embodiment, two core bars 4 having the same shape and the same length are prepared and inserted from both sides of the roof rail body 1.
That is, actuators (not shown) are arranged on both sides of the work table 3, and the actuators (not shown) hold the end of the roof rail body 1 and can be expanded and contracted in the coaxial direction. 4 is inserted into the roof rail body 1, and the cored bar 4 can be pulled out from the roof rail body 1 when contracted.

Two types of cored bar 4 are prepared according to the depth of the concave groove 2, and the depth of the concave groove 2 is approximately ３ or less of the thickness of the roof rail body 1, and the inner surface of the roof rail body 1 is provided. When the pressing convex part which protrudes is very small and is less than the gap between the roof rail main body 1 and the cored bar 4, the pressure receiving surface of the cored bar 4 is formed smoothly as shown in FIG.
On the other hand, when the depth of the concave groove 2 is approximately ½ or more of the thickness of the roof rail body 1 and the pressing convex portion 6 is equal to or larger than the gap, the concave groove 2 corresponds to the concave groove 2 as shown in FIGS. A plurality of wide concave grooves 7 are formed continuously in the axial direction on the pressure receiving surface of the cored bar 4 so that the pressing convex portions 6 can be accommodated in the concave grooves 7.

A substantially bell-shaped steel forming roll 8 is rotatably provided immediately above the work table 3, and a curved peripheral surface 8a as a pressing surface thereof is disposed so as to be engageable with the curved peripheral surface 1a of the roof rail body 1. In addition, a plurality of elongated ellipse-shaped or leaf-shaped molded convex portions 9 are arranged in a double-row staggered pattern along the circumferential direction of the curved peripheral surface 8a.
The forming roll 8 is provided so that the vertical position can be adjusted, and the pressing allowance or forming allowance for the roof rail body 1 can be adjusted during the adjustment. The forming roll 8 can be moved from one end to the other end of the work table 3 along the axial direction directly above the roof rail body 1 via a drive mechanism (not shown), and the circumferential surface of the roof rail body 1 is moved during the movement. Uniform molding is possible.

The molding convex portion 9 is appropriately surface-cured by quenching or the like, and its shape is formed in a horizontally long elliptical column shape that is the same shape as the concave groove 2, and its tip surface is the same shape as the curved peripheral surface 1a as shown in FIG. The projecting height is about 1.3 to 1.5 times the wall thickness of the roof rail body 1, and the depth of the groove 2 is set to about 0 of the wall thickness of the roof rail body 1. .3 to 0.5 times.
A rotating shaft 10 linked to a drive motor (not shown) projects from both ends of the molding roller 8 and is supported rotatably on a bearing (not shown). The rotating shaft 10 is disposed orthogonal to the axial direction of the roof rail body 1, and the curved peripheral surface 8 a of the forming roll 8 is disposed opposite to the curved peripheral surface 1 a of the roof rail main body 1.

For forming the bottom and side patterns of the roof rail body 1, instead of the bell-shaped molding roll 8 described above, the pressing surface is formed in a substantially drum shape, and a plurality of pressing surfaces are formed on the intersecting pressing surfaces. The forming roll is replaced with a forming roll, and the forming roll 8 is moved up and down to adjust the forming allowance. Then, the forming roll 9 rotates and moves along the roof rail body 1, and the groove 2 is formed on the bottom and side surfaces. In this embodiment, the present invention is applied to a ruled frame main body having an irregular cross section. However, the present invention may be applied to a ruler main body having a circular pipe or a rectangular pipe cross section. In addition, the present invention can be applied not only to the main body of the rail frame but also to building equipment such as a handrail and a clothes rack, gardening supplies, a cane, and the like.
Furthermore, although an extruded aluminum tube is selected as the material of the present invention, it can also be applied to aluminum alloys or copper alloys with similar hardness, and even thin-walled steel tubes.

  When the pattern forming apparatus X configured as described above is used to form a pattern with the recessed grooves 2 on the surface of the extruded aluminum roof rail body 1, the roof rail body 1 is first placed on the work table 1. The side peripheral surface is pressed against the engagement surface 3a, and a pair of stoppers (not shown) are installed in the length direction of the work table 1, and the end of the roof rail body 1 is brought into contact with the stoppers. The movement of the roof rail body 1 in the axial direction is restrained. This situation is as shown in FIG.

Next, the metal cores 4 and 4 are inserted from both sides of the roof rail body 1 through actuators (not shown). The actuator (not shown) is installed on both sides of the work table 1, and the actuator (not shown) holds one end of the metal core 4 to extend, and the other end of the metal core 4 is connected to the roof rail. Insert into the body 1.
The pair of core bars 4 and 4 are inserted from both sides of the roof rail main body 1 and both inner end portions abut on the roof rail main body 1 to be stationary. This situation is as shown in FIG.

At that time, the cored bar 4 is selectively used depending on the depth of the concave groove 2, and the selected cored bar 4 is inserted as described above. That is, when the concave groove 2 is shallow, the one shown in FIG. 1A having a smooth peripheral surface is used. When the concave groove 2 is deep, a plurality of concave grooves 7 are axially provided on the peripheral surface. The continuously formed one shown in FIG. 5 is used. In this case, the insertion method into the roof rail main body 1 by the two-way cored bar 4, the molding method by the molding convex portion 9, and the pattern formation by the concave groove 2 are substantially the same.
After the core bars 4 and 4 are inserted into the roof rail body 1 in this way, the outer ends of the core bars 4 and 4 are held by an actuator (not shown) to prevent the core bars 4 and 4 from swinging and the roof rail body 1 from swinging. .

Next, the forming roll 8 is moved downward to adjust the pressing allowance or forming allowance of the forming convex portion 9 against the curved peripheral surface 1a. That is, a small molding allowance is set for forming the shallow groove 2, and a large forming allowance is set for forming the deep groove 2.
Thus, after adjusting the molding allowance, the molding roll 8 is rotationally driven and simultaneously moved in the axial direction along the roof rail body 1 to press-mold the plurality of concave grooves 2 on the surface of the roof rail body 1.
In this case, since the pressing force or pressing displacement by the forming convex portion 9 is supported by the cored bar 4, the roof rail body 1 is not bent or deformed, and smooth and safe forming of the concave groove 2 is promoted. This situation is as shown in FIG.

  At that time, since the front end surface of the molding convex portion 9 of the molding roll 8 is formed in the same curved surface as the curved surface 1a of the roof rail body 1, the bottom of each concave groove 2 is the same as the curved surface 1a. Uniformly shaped to create an uncomfortable appearance. This situation is as shown in FIGS. 4 (a) and 4 (b).

  On the other hand, when the deep groove 2 is formed, the pressing convex portion 6 protrudes below the inner surface of the roof rail body 1, and the pressing convex portion 6 is accommodated in the concave groove 7. This situation is as shown in FIGS. 6 (a) and 6 (b). Since the pressing force or pressing displacement by the forming convex portion 9 is supported by the cored bar 4, the roof rail body 1 is not bent or deformed, The deep groove 2 is formed smoothly and safely.

Thus, after forming the concave groove 2 over the entire length of the curved peripheral surface 1a, the rotation and movement of the forming roll 8 are stopped, the actuator is contracted, and the core bars 4 and 4 are pulled out from the roof rail body 1. This situation is as shown in FIG.
At that time, when the shallow groove 2 is formed, the pressing protrusions on the inner surface of the roof rail body 1 by the forming protrusions 9 are none or very small as shown in FIGS. 2 (a) and 2 (b). The core bars 4 and 4 can be smoothly removed from the roof rail body 1 by the contraction operation.

  On the other hand, when the deep groove 2 is formed, the pressing protrusion 6 protruding from the inner surface of the roof rail body 1 is housed in the groove 7 formed continuously in the axial direction on the surface of the core metal 4. The core bars 4 and 4 can be smoothly taken out from the roof rail body 1 along the concave groove 7 by the contraction operation of the actuator.

In this way, after forming the pattern by the concave groove 2 on the curved peripheral surface 1a of the roof rail body 1, the roof rail body 1 is substantially inverted, the bottom surface and the side surface are positioned at the upper position, and the posture is appropriately restrained using a jig (not shown). Further, one end of the core bars 4 and 4 is held in each actuator by changing the phase, and is inserted into the roof rail body 1.
On the other hand, a forming roll 8 having a bell shape or a drum shape is prepared, and a plurality of forming convex portions 9 are provided on the pressing surfaces intersecting each other, and the forming roll 8 is moved up and down. Then, after adjusting the molding allowance, it rotates and moves along the roof rail body 1 to press-mold the concave grooves 2 on the bottom surface and the side surface.

And after forming the pattern by the concave groove 2 in the curved peripheral surface 1a of the roof rail main body 1, a bottom face, and a side surface, this roof rail main body 1 moves to a curve shaping | molding process, and bend | folds in a three-dimensional direction.
At that time, since the rigidity of the roof rail body 1 is improved by the large number of concave grooves 2, the spring back against the bending formation is suppressed, the increase of the bending amount in anticipation of the spring back is suppressed, and the small bending force Makes the folding easy and accurate

  Since the roof rail body 1 manufactured in this way is formed with a large number of concave grooves 2 on substantially the entire surface of the curved peripheral surface 1a, the bottom surface, and the side surface to form a dot pattern, Cover the peripheral surface with synthetic resin mixed with glass fiber to form a textured pattern, or cover the peripheral surface of the roof rail body with synthetic resin or apply paint, and then apply the convex part of the roll before curing. Compared with the method of obtaining a dotted pattern by pressing, the manufacturing process is simple, does not require large and expensive equipment, and the molding process or labor can be reduced, so that it can be manufactured easily and inexpensively.

Therefore, the aesthetics and design of the roof rail body 1 or the surface of the metal tube can be improved, and the production of a pattern according to the concept of a product such as an automobile to be installed can be realized.
Further, since the roof rail body 1 of the present invention directly forms the scattered pattern on the substrate peripheral surface, there is no deterioration over time and wear, and a reliable and stable pattern can be maintained over a long period of time. .
In addition, since the roof rail body 1 has a large number of concave grooves 2 arranged directly in the form of dots on the peripheral surface of the substrate, the rigidity is improved and the mechanical strength is enhanced. The deformation and breakage due to the applied load can be prevented.

  Further, the roof rail body 1 has a plurality of concave grooves 2 formed on the surface thereof, and Karman vortices are formed in the concave grooves 2 when the vehicle travels to form a running resistance. Therefore, like the conventional roof rail or roof rail main body 1, The longitudinal section along the front-rear direction is substantially streamlined, which suppresses or reduces the generation of lift due to the air flow on the surface of the vehicle body, promotes stabilization of the vehicle body, and improves high-speed travelability.

Such a roof rail body 1 is used by attaching legs (not shown) to both ends and attaching the legs to a roof panel (not shown) of an automobile.
In this case, since the scattered pattern by the concave grooves 2 is directly formed on almost the entire surface of the roof rail body 1, the pattern is not deteriorated or deteriorated or consumed even when exposed to wind and rain or sunlight. The initial pattern can be maintained reliably and stably.

7 to 12 show other embodiments of the present invention, and the same reference numerals are used for the components corresponding to the above-described embodiments.
Among these, FIG. 7 shows a second embodiment of the present invention, and this embodiment shows various forming methods of the concave groove 2 by the forming roll 8 of the pattern forming apparatus X. First, in FIG. 7A, the pressing allowance or forming allowance of the forming roll 8 against the roof rail body 1 is set in two ways of 0 (no) or 1 (present), and the presence or absence of the groove 2 is formed. .
That is, the pressing allowance or forming allowance of the forming roll 8 against the both end regions Z1, Z3 of the roof rail body 1 is set in the same manner as in the above-described embodiment, and the concave groove 2 having a certain depth is formed, while the roof rail body The pressing allowance or forming allowance of the forming roll 8 for the intermediate zone Z2 of 1 is set to zero, and the forming of the concave groove 2 in that region is stopped.

The pressing allowance of the forming roll 8 or the zero value of the forming allowance is set by raising the forming roll 8 directly above the roof rail body 1 and making the pressing or forming impossible, and the upward displacement is performed. A patternless state is formed by maintaining.
Then, at the end of the intermediate zone Z ₂ , a pressing allowance or forming allowance similar to that of the end zone Z ₁ is set again on the forming roll 8, and this press allowance is applied to the surface of the end zone Z ₃ of the roof rail body 1. A concave groove 2 having a similar depth is formed.
In this case, the transition of the pressing allowance or forming allowance of the forming roll 8 is as shown by the chain line in the figure, and is set deep in both end regions Z ₁ and Z ₃ , and the pressing allowance or forming allowance is zero in the intermediate region Z _2. Is set to
By forming the presence or absence of the groove 2 in the roof rail body 1 in this way, a beautiful impression due to the presence or absence of a pattern and a dynamic impression due to a change in appearance are induced.

7 (b) is molded to FIG shallow groove 2 in Z ₂ region of no pattern of (a), the pressing margin to molding allowance set deeper than that at both ends zone Z _4, Z ₆ is set slightly shallower the pressing margin to molding allowance in the intermediate zone Z _5. Therefore, after the forming roll 8 deeply pressing the roof rail body 1 in Z ₄ areas, pressed slightly rises and shallow in Z ₅ range, again in Z ₆ region, it is deeply pressed. Changes in the pressing margin to molding cost of the forming roll 8 during its like a chain line shown in the drawing, forming a vertical displacement of slightly increased in the intermediate zone Z _5.
Thus forming a clear pattern by grooves 2 at both ends of the roof rail body 1, to form a light pattern in the middle zone Z _5, thereby improving the appearance repeatedly forming a gradation pattern.

FIG. 7 (c) shows the pattern forming opposite to FIG. 7 (b), in which the pressing allowance or forming allowance is set shallow in both end areas Z ₇ and Z ₉ and the pressing allowance or forming allowance is deepened in the intermediate area Z _8. It is set. Thus, the forming roll 8 after shallow pressed roof rail body 1 in Z ₇ ranges, deeply pressed in Z ₈ range, again in Z ₉ range, and shallow pressed. Changes in the pressing margin to molding cost of the forming roll 8 during its like a chain line shown in the drawing, to form a vertical displacement slightly lowered in the intermediate zone Z _8.
In this way, a light pattern by the concave grooves 2 is formed at both ends of the roof rail body 1, and a clear pattern is formed in the intermediate area, and a gradation of the pattern is repeatedly formed to improve the aesthetic appearance.

FIG. 7 (d) shows a pattern formation different from that described above, forming a pattern by the concave groove 2 over the entire length of the roof rail body 1, forming the pattern lightly at one end and clearly forming at the other end, In the middle region, the pattern is gradually formed clearer or lighter, and the gradient of the pattern is formed over the entire length to improve the aesthetic appearance.
Accordingly, the pressing allowance or molding allowance is set shallow at one end of the roof rail body 1, the pressing allowance or forming allowance is set deep at the other end, and the pressing allowance or forming allowance is gradually increased or gradually decreased during that time. The transition of the pressing allowance or forming allowance of the forming roll 8 at that time is like the chain line shown in the figure, and is inclined linearly from one end to the other end.

In any of the embodiments shown in FIGS. 8 to 11, the roof rail body 1 to be processed is press-molded by moving the molding convex part 16 up and down instead of roll molding in which the molding convex part 9 is rotated and press-molded. The pattern is formed by press molding.
Among these, FIG. 8 shows a third embodiment of the present invention. In this embodiment, a lower die 12 as a molding die is placed on a bed 11 of a press machine, and an upper die is placed above the lower die 12. 13 is arranged to be movable up and down.
Formed in the lower mold 12 is a molding groove 14 that accommodates the lower part of the roof rail body 1, and formed in the upper mold 13 is a molding groove 15 that engages with the upper part of the roof rail body 1. Forming convex portions 16 for forming the concave grooves 2 are arranged in a double row staggered pattern on the inner surface facing the peripheral surface 1a.

According to this embodiment, when the pattern by the concave groove 2 is formed on the roof rail main body 1, the core metal 4 is inserted into the roof rail main body 1, the roof rail main body 1 is accommodated in the forming groove 14, and Then, the upper mold 13 is moved downward to press the plurality of forming convex portions 16 on the curved peripheral surface 1a to form the plurality of concave grooves 2.
At that time, the cored bar 4 shown in FIG. 1 (a) is used when the shallow groove 2 is formed, and the groove 7 is formed when the deep groove 2 is formed. The metal core 4 shown in FIG. 1 is used, and this is inserted using the actuator.
The concave grooves 2 are arranged in a double-row staggered pattern along the axial direction of the roof rail body 1, and the cored bar 4 is taken out from the roof rail body 1 after molding. In this way, by pressing the concave groove 2 using the molds 12 and 13, the concave groove 2 can be accurately formed as compared with roll molding.

FIG. 9 shows a fourth embodiment of the present invention. The lower mold 12 of this embodiment is substantially the same as the third embodiment described above, and the vertical and horizontal dimensions of the molding groove 14 are formed to be substantially the same. The bottom surface and the side surface of the roof rail body 1 are formed in the groove 14 so as to be engageable with each other. Further, the upper die 13 is formed in a punch or shaft shape, and a single forming convex portion 17 having the same shape as the concave groove 2 is projected from the lower end portion thereof.
The lower mold 12 is movable in the movement direction of the roof rail body 1, that is, in the direction orthogonal to the axial direction. In the embodiment, the lower mold 12 is movable by one pitch of the groove 2.

  According to this embodiment, when a pattern by the concave groove 2 is formed on the roof rail body 1, the core metal 4 is inserted into the roof rail body 1 using the actuator, and the roof rail body 1 is accommodated in the forming groove 14. Then, the upper die 13 is moved downward from above the lower die 12, the convex portion 17 is pressed against the curved peripheral surface 1a to form the concave groove 2, and after forming, the roof rail body 1 is moved by a predetermined amount in the axial direction. Thus, the next concave groove 2 in the axial direction is formed. At that time, the cored bar 4 used for forming the shallow or deep concave groove 2 is the same as described above.

Then, after forming a predetermined number of concave grooves 2 on the curved peripheral surface 1a, the roof rail body 1 is rotated by 90 °, the side surfaces thereof are accommodated in the molding grooves 14, and the lower mold 12 is moved by one pitch of the concave grooves 2. Thereafter, the upper mold 13 is moved downward to press the convex portion 17 against the curved peripheral surface 1a, and the concave groove 2 is formed.
After forming the concave groove 2, the roof rail body 1 is moved by one pitch in the axial direction to form the next concave groove 2 in the axial direction. After forming a predetermined number of the concave grooves 2, the lower mold 12 is moved by one pitch of the concave grooves 2 to move the upper mold 13 downward, and press the convex portion 17 on the curved peripheral surface 1a to form the adjacent concave grooves 2. Mold. Thereafter, this operation is repeated, and the concave grooves 2 are arranged in a double row staggered pattern on the curved peripheral surface 1a.

FIGS. 10 and 11 show fifth and sixth embodiments of the present invention, and these embodiments are patterns for a roof rail body 1 of a circular tube or a rectangular tube instead of the roof rail body 1 having a modified cross section as described above. Applied to molding. Therefore, the metal core 4 used for these has a bar shape with the same cross section.
Among these, in the fifth embodiment shown in FIG. 10, substantially semicircular molding grooves 14 and 15 are formed in a pair of upper and lower molds 12 and 13, and molding convex portions 16 are formed in a double row staggered pattern in the molding groove 15. It is arranged.
Further, the sixth embodiment shown in FIG. 11 belongs to an application form of the fourth embodiment shown in FIG. The pattern formation according to these embodiments is performed in the same manner as in the previous embodiments.

FIG. 12 shows a seventh embodiment of the present invention. These embodiments are formed by roll forming or press forming, and the groove 2 of various shapes is used instead of the elongated oval or leaf-shaped groove 2. Shows the pattern.
Of these, FIG. 12A shows that one or a plurality of elongated grooves 2 are formed along the axial direction of the roof rail body 1 to reinforce the linear impression and wipe away the gentle impression due to the dot pattern. doing.
FIG. 12B shows a plurality of substantially square concave grooves 2 arranged in a double-row staggered pattern at intervals in the axial direction of the roof rail body 1 to form a large square pattern to enhance the visual impression. doing.
Further, FIG. 12C shows a plurality of substantially square-shaped concave grooves 2 arranged in a line at intervals in the axial direction of the roof rail body 1 to strongly express a bold and bold impression due to a large square pattern. I'm out.
In FIG. 12 (d), a plurality of substantially scale-shaped concave grooves 2 are arranged in a line at intervals in the axial direction of the roof rail body 1, and a dynamic impression due to the scale pattern is induced.

  As described above, the groove forming method, the groove forming apparatus, and the metal tube of the metal tube surface of the present invention can be applied to the surface of the metal tube without requiring a synthetic resin coating or expensive and large-scale equipment on the surface of the metal tube. Grooves are directly formed to easily and inexpensively produce patterns with grooves, improve the appearance and design of the surface of metal pipes, and create patterns according to the concept of automobiles, as well as wear and alteration of patterns. Therefore, the initial pattern can be maintained over a long period of time, and the strength of the metal tube can be enhanced to improve the service life.

1 Metal pipe (roof rail body)
2 Concave groove 4 Core metal 6 Pressing convex part 8 Molding roll 9, 16, 17 Molding convex part 12 Molding die (lower mold)
13 Mold (Upper mold)
15 Forming groove

Claims (18)

  One or a plurality of forming projections are provided on the pressing surface of the rotatable forming roll or the forming groove of the forming mold movable up and down, and the forming roll is rotated to move in the axial direction of the metal tube, or the forming mold In the method for forming a groove on the surface of the metal tube, the upper metal is moved up and down, and the groove is formed by pressing the molding convex portion on the surface of the metal tube. To support the metal tube, and directly press the molding convex part on the surface of the metal tube directly above the core metal or the surface of the metal tube on the lower die, and directly press-mold the concave groove on the surface of the metal tube. A method for forming a groove on the surface of a metal tube.   The pressing amount of the upper part of the forming roll or molding die with respect to the whole or part of the axial direction of the metal tube is kept constant, and the depth of the concave groove in the whole or part of the metal tube is formed constant. The method for forming a groove on the surface of a metal tube according to claim 1.   The concave portion of the surface of the metal tube according to claim 1, wherein the pressing amount of the upper die of the forming roll or the molding die with respect to the plurality of regions in the axial direction of the metal tube is adjusted to adjust the depth of the groove in the plurality of regions. Groove forming method.   The pressing amount of the upper part of the molding roll or molding die with respect to the entire axial direction of the metal tube is gradually increased or decreased from one end to the other end, and the depth of the concave grooves is gradually increased from one end to the other end. The method for forming a groove on the surface of a metal tube according to claim 1, wherein the groove is reduced.   A core metal having a smooth pressure-receiving surface is used when forming a shallow concave groove, and a core metal having a concave groove that accommodates a pressing projection of a metal tube is formed on the pressure-receiving surface when forming a deep concave groove. Item 8. A method for forming a groove on the surface of a metal tube according to Item 1.   2. A method for forming a groove on the surface of a metal tube according to claim 1, wherein a cored bar is inserted from both sides of the metal tube, the inner end portions thereof are brought into contact with each other, and the outer end portions thereof are held immovably.   The method for forming a groove on the surface of a metal tube according to claim 1, wherein the metal tube is made of an extruded aluminum material.   One or a plurality of forming projections are provided on the pressing surface of the rotatable forming roll or the forming groove of the vertically movable forming mold, and the forming roll is rotated so as to be movable in the axial direction of the metal tube, or formed. An apparatus for forming a groove on the surface of a metal tube that moves the upper mold of the mold up and down and presses a molding convex portion on the surface of the metal tube so that a groove can be formed. The metal tube has substantially the same shape as the metal tube. A cross-section cored bar is provided so that it can be inserted, a metal tube is supported via the cored bar, and a molding convex part is provided on the surface of the metal tube directly above the cored bar or on the metal tube surface on the lower mold so that it can be pressed directly. An apparatus for forming a groove on the surface of a metal tube, wherein the groove is directly press-molded on the surface of the metal tube.   The apparatus for forming a concave groove on a metal tube surface according to claim 8, wherein a plurality of molding convex portions are arranged on a pressing surface of the molding roll or a molding groove of a molding die.   The apparatus for forming a groove on the surface of a metal tube according to claim 8, wherein the pressing amount of the upper die of the forming roll or the molding die can be adjusted in the whole or part of the axial direction of the metal tube.   The apparatus for forming a concave groove on the surface of a metal tube according to claim 8, wherein the pressing amount of the upper die of the forming roll or the molding die can be gradually increased or gradually decreased from one end of the metal tube to the other end.   9. The metal tube surface according to claim 8, wherein the metal core has a pressure-receiving surface that is formed smoothly, or a groove that can accommodate a pressing convex portion of the metal tube is continuously formed on the pressure-receiving surface in the axial direction of the peripheral surface. Concave groove forming device.   In a metal tube in which one or a plurality of concave grooves are formed on the surface via one or a plurality of molding convex portions provided on a pressing surface of a rotatable molding roll or a molding groove of a mold that can move up and down. A metal tube characterized in that the groove is directly formed by directly pressing the molding convex part.   The metal tube according to claim 13, wherein a groove forming region and a non-forming region are formed in the axial direction of the surface.   The metal pipe according to claim 13, wherein a plurality of types of concave grooves having different forming depths are formed in the axial direction of the surface.   The metal tube according to claim 13, wherein a plurality of concave grooves having a forming depth gradually increased or gradually decreased from one end to the other end in the axial direction of the surface.   The metal tube according to claim 13, wherein the metal tube is made of an aluminum extruded material.   The metal pipe according to claim 17, wherein the metal pipe is a roof rail body of an automobile roof rail.

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