JPH07155831A - Manufacture of tapered rectangular tube - Google Patents

Abstract

PURPOSE:To efficiently manufacture a tapered rectangular tube by drawing, and to smoothly perform a knockout at the time of the drawing by using the main pressure of a press. CONSTITUTION:In a head-drawing process, a head-drawn rectangular tube is attained by drawing the top end part of a rectangular tube stock. In a total length drawing process, a tapered rectangular tube 4 is obtained by drawing the head-drawn rectangular tube with a male die 16 and a female die 19 by the first press operation of a ram 20. At that time, the tapered rectangular tube 4 comes into press contact with the inner surface of the female die 19. At the time of the second press operation of the ram 20, an upper bolster 25 is inserted between the bottom surface of the ram 2 and the upper surface of a block 22 for knockout. The main pressure of the ram 20 is directly received by the block 22 for knockout through the upper bolster 25, and the tapered rectangular tube 4 in press contact with the inner surface 19a of the female die 19 is pushed downward and subjected to the knockout. Since the large main pressure of a press can be used, a knockout work is smoothly performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a tapered rectangular tube which is suitable for use in a connecting portion between rectangular steel tube columns having different diameters and which is suitable for producing a truncated square pyramidal tapered rectangular tube by drawing.

[0002]

2. Description of the Related Art In a steel structure building, when a rectangular steel pipe column having a smaller diameter as it goes upstairs is used, a tapered rectangular pipe generally in the shape of a truncated quadrangular pyramid is used for connecting the rectangular pipes having different diameters. Is used. As shown in the plan view and the perspective view of FIG. 15, the tapered rectangular tube includes a four-sided tapered rectangular tube (fourth surface (a) in FIG. 15), and a three-sided tapered rectangular tube (three-sided tapered tube (same as the same)). There are three types: a double-sided taper rectangular tube (Fig. (B)) in which only two surfaces are tapered. Conventional methods of manufacturing this kind of tapered rectangular tube include casting, forming by welding four trapezoidal plate materials, and bending one or two plate materials cut into a predetermined development view shape. For example, there is one in which the abutting portion is welded and connected after being formed into a tapered rectangular tube shape. Further, there is a method of forming by drawing with a metal mold having a truncated square pyramidal male mold and a female mold corresponding thereto (the method of Japanese Patent Application No. 4-223643 adopts this method).

[0003]

The method other than the above-mentioned drawing using a die has complicated steps and is not easy to manufacture. The draw forming method using the die has a simple process, but since the draw forming is performed with an extremely large pressing force when the draw forming is performed, the tapered square tube drawn into the truncated quadrangular pyramid shape has an inner surface of the female die. There is a problem in that it is not easy to crimp strongly from the female mold and knock out from this female mold. Further, since a very large pressing force is required, a large press machine is required, and there is also a problem that the manufacturing cannot be said to be simple in this respect.

The present invention has been made in view of the above circumstances, and provides a method for manufacturing a tapered rectangular tube which can be manufactured by drawing, does not require a large pressurizing force and can be knocked out easily. The purpose is to do.

[0005]

According to the present invention for solving the above-mentioned problems, one side end of a material rectangular tube is squeezed by a male type having a truncated pyramid shape and a corresponding female type. Corresponding to the head drawing process to obtain a head-drawing square tube which is formed into a truncated quadrangular pyramid shape only on one side, and the head-drawing square tube having a truncated quadrangular pyramid shape over the entire length. A method of manufacturing a tapered rectangular tube comprising a full-length drawing step of obtaining a tapered rectangular tube by drawing with a female die, wherein the full-length drawing step is performed by the first pressing operation of a ram of a press machine to form the male die. The step of pressing the covered head-throttle square tube with the female die to draw and form the final shape of the taper square tube, and contacting the female die with the upper end of the taper square tube that is in close contact with the inner surface of the female die. To provide a knockout block that can be moved up and down relative to the female mold so as to obtain In the meantime, this knockout block consists of a knockout process in which the second press operation of the ram directly pressurizes and lowers it relative to the female die, and knocks out the tapered rectangular tube that is in close contact with the inner surface of the female die. Characterize.

[0006]

In the above-described method for manufacturing a tapered rectangular tube, in the head drawing step, one end of the material square tube is drawn by a male mold and a female mold, and only one end has a truncated quadrangular pyramid shape. A square head tube is formed. In the full length drawing step, the above-mentioned head-drawing square tube is drawn by a male die and a female die, and a tapered square tube having a truncated pyramid shape as a whole is formed. In this full-length drawing process, the material square tube covered by the male mold is pressed and drawn by the female mold by the first pressing operation of the ram of the press machine.
A tapered rectangular tube is obtained, but this tapered rectangular tube rises with the female mold while being crimped to the inner surface of the female mold. 2 of the following rum
Before the second press operation, the knockout block is positioned between the ram and the upper end of the tapered rectangular tube, and when the second press operation is performed, the knockout block is pressed by the main pressing force of the press machine into the female inner surface. Knock out the taper square tube crimped to.

Since the knockout work for peeling off the tapered rectangular tube crimped to the inner surface of the female mold is carried out by utilizing the main pressing force of the pressing machine, a sufficiently large force can be utilized. When the draw forming in the full length drawing process is performed by one pressing operation (excluding the knockout pressing operation),
For example, the force required for knockout becomes larger than that in the case of molding in two steps, but since the main pressing force of the press machine sufficiently large for knockout can be used as described above, knockout is actually possible.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 14 is a view for explaining the outline of the manufacturing process, in which the long rectangular steel tube 1 of FIG. 14A is cut to obtain a short material rectangular tube 2 of a predetermined length as shown in FIG. . The upper end of the material square tube 2 is drawn to obtain a head-drawing square tube 3 in which only the upper end has a truncated quadrangular pyramid shape. This FIG.
The step of obtaining the square tube 3 of (c) is the head step.
The shape of the head portion of the head diaphragm rectangular tube 3 may be such that each surface has a slight curvature. Subsequently, the head-drawing rectangular tube 3 is drawn to obtain a tapered square tube 4 having a truncated pyramid shape over the entire length. The step of obtaining the tapered rectangular tube 4 of FIG. 14D is the full length drawing step. The tapered rectangular tube 4 shown in the figure is a tetrahedral diaphragm tube.

1 and 2 show a head-drawing die 10 used in the head-drawing step and a pressing operation. In FIG. 1, reference numeral 5 is a ram of a hydraulic or mechanical press machine, and reference numeral 6
Is the pedestal of the press machine. The lower die 7 fixed to the pedestal 6 is fixed with the male die 8 which is the lower die of the head stop die 10 and the ram 5 is fixed with the female die 9 which is the upper die corresponding to the shape of the male die 8. is doing. In the male die 8, a portion 8a corresponding to the upper end portion of the material rectangular tube 2 has a substantially truncated pyramid shape, and a lower portion 8b following the portion has a quadrangular prism shape. The male type 8 in the illustrated example
In order to easily take out the material after molding, the diameter of the lower portion 8c, which is unnecessary for molding, is reduced.

Then, as shown in FIG. 1, the material square tube 2 is attached to the male mold 8.
When the female die 9 is lowered together with the ram 5, as shown in FIG. 2, the material square tube 2 is made up of the male die 8 and the female die 9, and only the upper end portion thereof has a truncated pyramid shape. It becomes tube 3.

3 to 11 show the full-length drawing die 15 and the pressing operation used in the full-length drawing step for obtaining the tapered rectangular tube 4 from the head drawing rectangular tube 3. A male mold 16, which is a lower mold of the full-length drawing die 15, has a truncated quadrangular pyramid shape over the entire length, is provided with a receiving portion 16a for receiving the head-drawing rectangular tube 3 at a lower end, and is fixed on a pedestal 17 of a press machine. It is fixed to the lower die holder 18.

A female mold 19 which is the upper mold of the full length drawing mold 15.
A hollow portion 19b having a truncated quadrangular pyramid-shaped inner surface 19a corresponding to the truncated quadrangular pyramid-shaped outer surface of the male die 16 vertically penetrates through the ram 20 of the press machine as shown in FIG. It is housed in a recess 21a formed in the upper surface of the fixed upper die holder 21 and having a rectangular shape when viewed from above, and is supported slidably upward with a gap a with respect to the lower surface of the ram 20.

Further, the knockout block 22 projects into the hollow portion 19b of the female die 19 and has a rectangular lower portion 22a and a rectangular upper portion 22b larger than the rectangular lower portion 22a.
The upper part 22b is accommodated in a rectangular recess 19c formed on the upper surface side of the female mold 19 and is supported slidably upward with a gap b with respect to the upper surface of the female mold 19. ing. The knock-out block 22 has a lower end surface capable of contacting the upper end of the tapered rectangular tube 4 which is crimped to the inner surface 19a of the female mold 19 as described later.

Further, the lower die holder 18 is provided with a lower bolster 23 having a height of dimension c so as to be slidable left and right in FIG. 3, and an air cylinder 24 for driving the lower bolster 23 forward and backward is provided. Has been.

As shown in FIG. 11, the upper die holder 21 is provided with an upper bolster 25 inserted horizontally between the lower surface of the ram 20 and the upper surface of the knockout block 22. An air cylinder 26 that drives forward and backward is provided. The upper bolster 25 is usually provided with a groove 21 provided on the upper surface side of the female die 19 and the upper die holder 21.
It is housed in b, 19d and is shown in FIG.
Slide 1 to the position indicated by the chain double-dashed line. Reference numeral 26a is a cylinder rod of the air cylinder 26, and reference numeral 26 is
Reference numeral b is a base of the air cylinder 26.

Next, the operation of forming the head-drawing square tube 3 into the tapered square tube 4 by the full-length drawing die 15 will be described. First, as shown in FIG.
Cover. At this time, the lower bolster 23 is retracted.

When the ram 20 is lowered by the first pressing operation of the ram 20, the female die 19 descends together with the upper die holder 21 to come into contact with the head diaphragm angular tube 3, and then, as shown in FIG. It rises relative to the upper die holder 21 and comes into contact with the lower surface of the ram 20, receives the main pressing force of the ram 20, and draws the head throttle angular tube 3 with the male die 16 to form the tapered rectangular tube 4. To do. At this time, the knockout block 22 is the male type 16
It is pushed up to the female die 19 and rises relative to the female die 19, but maintains a slight gap h with the ram 20.

Then, when the ram 20 is raised, the upper die holder 21 is slightly raised, and then the female die 19 is also raised together with the upper die holder 21. At this time, as shown in FIG. The tapered rectangular tube 4 drawn by
Since the inner surface 19a of 9 is strongly pressed, it rises together with the female die 19. At that time, the knockout block 22 slightly descends and comes into contact with the upper end surface of the tapered rectangular tube 4, and a slight gap d is formed between the knockout block 22 and the bottom of the recess 19c of the female die 19.
And rises together with the female mold 19.

Then, when the air cylinder 26 on the upper die holder 21 side is operated, the upper bolster 25 moves the upper die holder 21.
And, it slides in the grooves 21b and 19d of the female die 19 and advances, and is inserted between the lower surface of the ram 20 and the upper surface of the knockout block 22, as shown in FIG. at the same time,
The air cylinder 24 on the lower die holder 18 side is operated to move the lower bolster 23 forward so that it is positioned below the female die 19.

Next, when the ram 20 is lowered by the second pressing operation of the ram 20 and the female die 19 is lowered again, the female die 19 hits the lower bolster 23 and stops descending as shown in FIG. Ram 20 and upper die holder 21
However, since the female die 19 does not descend, the knockout block 22 receives the main pressing force of the ram 20 through the upper bolster 24 and pushes down the upper end of the taper square tube 4, as shown in FIG. The tapered rectangular tube 4 is peeled off from the inner surface 19a of the female die 19, that is, knocked out. The amount of depression of the tapered rectangular tube 4 required to knock out the tapered rectangular tube 4 with the knockout block 22 is usually 2 to 3 m.
It is about m, and at most 5 mm or less.

Subsequently, when the ram 20 is raised, the female mold 1
9 rises, and as shown in FIG.
It is left in a state of being lightly covered by. At the same time, the air cylinder 24 on the lower die holder 18 side is actuated to move the lower bolster 2
Retreat 3. Further, the air cylinder 26 on the upper die holder 21 side is operated, and the upper bolster 25 is also retracted. This prepares for the next drawing.

Next, as shown in FIG. 10, the tapered square tube 4 is taken out from the male mold 16 and is then molded.
Is covered with the male mold 16 and the next drawing is performed.

In the head drawing process shown in FIGS. 1 and 2, the operation of taking out the formed head drawing square tube 3 from the male die 8 and the operation of covering the material square tube 2 to be formed next on the male die 8 are shown in FIG. As shown in FIG. 12, the material square tube 2 or the head-drawing square tube 3 is sequentially laterally fed (upward and downward feeding in FIG. 12) on the front surface of the pedestal 6 of the press machine, which can be moved forward and backward by the air cylinder 27. It mounts on the attachment / detachment device 28 and is performed by this attachment / detachment device 28. Further, in the full length drawing process of FIGS. 3 to 11, the work of taking out the formed tapered rectangular tube 4 from the male mold 16 and the operation of covering the male mold 16 with the head drawn rectangular tube 3 to be molded next are almost the same as above. As shown in FIG. 13, the pedestal 17 of the press machine is
The head diaphragm square tube 3 or the taper square tube 4 is sequentially traversed on the front side of the device, and is mounted on the attaching / detaching device 30 which can be moved forward / backward by the air cylinder 29.

The knockout block used in the full length drawing step is not limited to the structure of the embodiment. In short, it is arranged between the lower surface of the ram 20 and the upper end of the tapered rectangular tube 4 that is in close contact with the inner surface 19a of the female die 19, and is movable up and down relative to the female die 19. Anything that can contact the upper end of the tapered rectangular tube 4 may be used. The structure for directly pressurizing this knockout block by the second pressing operation of the ram 20 and lowering it relative to the female mold 19 is not limited to the upper bolster 25 of the embodiment, and various structures are conceivable.

Further, the drawing die 1 used in the head drawing process.
0 is not necessarily limited to the structure shown in FIGS. In short, one end of the material square tube 2 is drawn by a male mold whose head is substantially truncated pyramidal and a female mold corresponding thereto, and only one end is substantially truncated pyramidal. It suffices as long as it can be the head diaphragm square tube 3 that forms Further, the full-length drawing die 15 used in the full-length drawing process is not necessarily the one shown in FIG.
~ It is not limited to the structure shown in FIG. In short, it is only necessary that the tapered head tube 4 can be formed into a tapered rectangular tube 4 by drawing a head-shaped rectangular tube 3 with a male mold having a truncated quadrangular pyramid shape over its entire length and a female mold corresponding thereto.

The method of the present invention can be applied not only to the four-faced diaphragm pipe but also to the manufacture of a three-faced diaphragm pipe and a two-faced diaphragm pipe. In that case, in the head drawing process, one end of the material square tube 2 is drawn into a shape suitable for the three-sided drawing tube or the two-sided drawing tube, and then this head-drawing square tube is drawn into the three-sided drawing tube or the two-sided drawing tube. Draw into a tube.

[0027]

According to the present invention, since the tapered rectangular tube is manufactured by drawing using a press machine, the manufacturing efficiency is remarkably improved. In the full length drawing process to obtain the tapered rectangular tube, since the head drawing rectangular tube that has been partially drawn is drawn, the applied pressure is relatively small and the press machine used is not upsized. To be Further, in this full length drawing process, the forming process itself is a single pressing operation, which is efficient.

Since the knockout work for peeling the tapered rectangular tube from the inner surface of the female mold is performed by utilizing the main pressing force of the press machine, a sufficiently large force can be utilized and the knockout is smoothly performed. Also in this respect, the manufacturing efficiency is improved.

[Brief description of drawings]

FIG. 1 is a view for explaining an embodiment of a method for manufacturing a tapered rectangular tube of the present invention, showing a state before a pressing operation in a head drawing step for obtaining a head drawn rectangular tube.

FIG. 2 is a diagram showing a state after a pressing operation in a head drawing step for obtaining a head drawing square tube.

FIG. 3 is a diagram showing a state before a pressing operation in a full length drawing step of drawing a tapered rectangular tube from a head drawn rectangular tube.

FIG. 4 is a diagram showing a stage following the first pressing operation in the full length drawing process, which is similar to FIG. 3;

FIG. 5 is a diagram showing a stage of the first pressing operation in the full length drawing process, which is subsequent to FIG. 4;

FIG. 6 is a view showing a state before the second pressing operation in the same full-length drawing step.

FIG. 7 is a diagram showing a stage following the process in FIG. 6 of the second pressing operation in the same full-length drawing process.

FIG. 8 is a diagram showing a stage following the process of FIG. 7 of the second pressing operation in the same full-length drawing process.

FIG. 9 is a diagram showing a stage following the process in FIG. 8 of the second pressing operation in the same full-length drawing process.

FIG. 10 is a diagram for explaining work after the completion of the full length drawing process.

11 is an enlarged cross-sectional view taken along the line AA in FIG.

FIG. 12 is a schematic plan view of an apparatus for performing the head drawing step shown in FIGS. 1 and 2.

FIG. 13 is a schematic plan view of an apparatus for performing the full length drawing step shown in FIGS.

FIG. 14 is a diagram illustrating a manufacturing process of the present invention.

15A and 15B are views for explaining the types of tapered rectangular tubes to be manufactured by the present invention. FIG. 15A shows a four-sided tapered rectangular tube, FIG. 15B shows a three-sided tapered rectangular tube, and FIG. ) Is a double-faced taper rectangular tube.

[Explanation of symbols]

 2 Material Square Tube 3 Head Drawing Square Tube 4 Tapered Square Tube 8 Head Drawing Mold Male Die 9 Head Drawing Die Female 10 Head Drawing Die 15 Full Length Drawing Die 16 Male of Full Length Drawing Die 17 Press Machine Cradle 18 Lower die holder 19 Female die for full-length drawing die 19a Female inner surface 19c Recesses 19d, 21b Groove 20 Press machine ram 21 Upper die holder 21a Recess 22 Knockout block 23 Lower bolster 24, 26 Air Cylinder 25 Upper bolster

Claims (1)

[Claims] 1. A material square tube is drawn at one end thereof with a male die having a truncated square pyramidal shape and a female die corresponding thereto, and only one end has a substantially truncated square shape. A head-drawing process for obtaining a pyramidal head-drawing square tube, and a tapered square tube is obtained by drawing the head-drawing square tube over its entire length with a truncated square-pyramidal male mold and a corresponding female mold. A method for manufacturing a tapered rectangular tube comprising a full length drawing step, wherein the full length drawing step presses a head drawing square tube covered by the male mold with the female mold by a first pressing operation of a ram of a press machine. A forming step for obtaining a tapered rectangular tube in a final shape by drawing, and the female die is vertically moved relative to the female die so that the female die can come into contact with the upper end of the tapered square tube that is in close contact with the inner surface of the female die. A knockout block that can be moved to is installed, and this knockout block is attached to the ram 2 A method for manufacturing a tapered rectangular tube, which comprises a knock-out step of directly pressing and lowering relative to the female mold by a second pressing operation to knock out the tapered rectangular tube that is in close contact with the inner surface of the female mold.