JPH0327288B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method and apparatus for manufacturing a cross tube by bulge forming of a tube, and is particularly applicable to a long aluminum tube with a small diameter to produce an optimal cross tube. The present invention relates to a manufacturing method and an apparatus therefor.

[Technical background of the invention]

Generally, in order to connect a tubular material with a smaller diameter to a tubular material, a bulging method is used as a means for protruding a short tube portion from one side of the tubular material.

Therefore, as a method of forming a short pipe part by bulging a long aluminum pipe with a small diameter as described above, the applicant has proposed drilling a pilot hole in the cross direction of the short pipe part forming position of the pipe material to be bulged. Set it up,
The tip of a drawing material inserted from outside the pipe through the pilot hole is connected to the top of a piece placed inside the pipe, and by pulling the drawing rod from outside the pipe, the peripheral portions of the pilot hole are successively projected outward. We have developed a method for manufacturing cross tubes using bulge processing, which efficiently forms cross-shaped short tube sections.

By the way, the apparatus for carrying out the above method is
As shown in the figure and FIG.
A tube holding surface 6 comprising a semicircular recess that holds the tube 5 on the mating surface of the lower die 2 and the upper die 3, which has an upper mold 3 stacked on top and fixed by bolts 4, 4; 7 is formed, and a through hole 8 penetrating vertically is bored in the center bottom of the tube holding surface 6 of the lower die 2, into which a drawing rod 9 can be freely inserted.
The tip of this drawing rod 9 is screwed into the top of a short tube forming piece 10 placed inside the tube material 5, and then the piece 10 is inserted into the pilot hole 1 by pulling the drawing rod 9.
After forming the short tube part 12 on one side of the tube material 5, the upper die 3 is removed and the formed short tube part 12 is inserted into the upper die 3. A hole 13 is provided and is thicker than the short pipe portion 12.
After the tube is housed in the tube, the short tube portion 12 can be formed on the other side in the same manner as described above. However, with this method, only the vertical direction can be formed, and the horizontal direction cannot be formed.

Therefore, as a method of forming a cross tube, as shown in FIG. 3, a hydroforming process using hydraulic pressure has been conventionally used. That is, a mold 15 divided into upper and lower parts is provided on the base 14, a pipe material 16 is inserted into this mold 15, and the mold 15 is closed by a mold clamping press 17.
At the same time, the hydraulic pistons 18, 18 disposed at both ends of the pipe material 15 are pushed by a pressure press 21 with hydraulic pressure increased through a pressure intensifier 20 driven by a hydraulic pump 19. Some are designed to form cross tubes.

[Problems with background technology]

With the above device, it is not possible to form a cross tube in the cases shown in Figures 1 and 2, and it is possible to form a cross tube in the case of Figure 3, but it is not possible to form a cross tube in the case of Figure 3, but it is possible to form a cross tube in the case of Figure 3. Since a mold is required, it is difficult to make a long mold when there is only one cross tube, but when there are multiple cross tubes, it is difficult to make a long mold, and even if it is made, it will require a huge amount of mold production It is expensive and requires high hydraulic pressure, making hydraulic processing equipment expensive. Furthermore, as hydraulic oil adheres to the inner and outer surfaces of the pipe material of the finished product, a process such as removal of this oil is required. Therefore, the price of products manufactured using this method is low, except in the case of mass production. It had drawbacks such as being expensive.

[Purpose of the invention]

In view of this, the present invention adds a relief hole in the 90 degree direction to the conventionally used bulge forming processing jig as shown in FIGS. The purpose of this invention is to provide a method and apparatus for manufacturing a long tube, which allows bulge forming and facilitates the manufacture of cross tubes.

[Summary of the invention]

In order to achieve the above object, the present invention provides a pipe material in which a single set or multiple sets of pilot holes are drilled in a cross direction for bulge processing, between pipe material holding surfaces formed on opposing surfaces of upper and lower molds. The upper and lower molds are clamped together and connected with bolts, and a draw rod is inserted into the pilot hole through one of the through holes drilled in the tube material holding surfaces of these molds facing each other, and its tip is placed inside the tube material. It was connected to a short tube forming piece, and this drawing rod was connected to a pressure device that drove it in the drawing direction, and by driving this, the lower short tube section was formed, and then the upper and lower molds were joined. Turn this over and mold the short tube section on the opposite side in the same way as above, then dismantle the upper and lower molds, turn the tube 90 degrees, and place the formed short tube section on the mating surface of the upper and lower molds. The upper and lower molds are bolted together again with the upper and lower molds placed in the relief holes between them, and the upper and lower short pipe parts are formed in the same manner as described above, thereby forming the short pipe parts in the cross direction. The present invention features a method for manufacturing an ulnar cross tube and the structure of an apparatus for carrying out this method.

[Embodiments of the invention]

Hereinafter, the present invention will be described with reference to FIGS. 4, 5, and 6, in which the same reference numerals are given to the same members as in FIGS. 1 and 2.

The apparatus for carrying out the method for manufacturing a cross tube of a long tube according to the present invention has a pair of upper and lower molds 22 and 23 that are provided with tube material holding surfaces 6 and 7 that sandwich a tube material 5. Through holes 8, 8 for bulge processing, which are opposed to each other, are provided vertically through the tube material holding surfaces 6, 7. Further, on the upper and lower mating surfaces of the pair of molds 22 and 23, relief grooves each consisting of semicircular recesses are provided in a direction perpendicular to the through holes 8 and 8, penetrating left and right. When the molds 22 and 23 are overlapped, the relief hole 2 has a larger diameter than the through hole 8.
4 is formed.

The drawing rod 9 inserted into the through hole 8 has a screw 9a formed at its tip, and this screw 9a is screwed into a screw hole on the top end surface of the short tube forming piece 10 disposed inside the tube material 5. It is designed to be inserted and coupled.

An actuating plate 25 is inserted into and fixed to the lower part of the drawing rod 9, and both ends of the actuating plate 25 are connected to the supporting legs 1,
1, and this protruding portion is pressurized in the direction of the arrow by a pressurizing device (not shown). The short pipe forming piece 1
0 has a cylindrical shape with an outer diameter corresponding to the inner diameter of the short tube section 12 to be formed, and its top part fits into the pilot hole 11 of the tube material 5 in the initial stage of forming and expands its periphery. In order to make it easier to use, it is formed into a tapered shape, and the screw hole is formed in the tip end surface of the tapered shape. It goes without saying that the diameter of the pilot hole 11 is smaller than the inner diameter of the short tube section 12 after molding.

Next, the effect will be explained.

To form a cross tube in the tube material 5, first, pilot holes 11, 11, etc. are bored in the vertical and horizontal directions of the tube material 5, and this tube material 5 is placed on the tube material holding surface 6 of the lower mold 23. After aligning the lower hole 11 with the through hole 8 of the mold 23, the upper mold 22 is placed on top, and both molds 22 and 23 are fixed with bolts 4. Next, pipe material 5
Insert the mold 2 into the screw hole of the short pipe forming piece 10 placed inside.
The screw 9a at the tip of the draw rod 9 inserted into the through hole 8 from the lower part of 3 is screwed together to couple.

After this, by applying pressure to both ends of the actuating plate 25 in the direction of the arrow with a pressure device and pulling out the piece 10, the peripheral portion of the pilot hole 11 of the pipe material 5 is removed from the piece 1.
The short tube portion 12 is expanded outwardly by the passage of the tube member 5, and a short tube portion 12 is formed to protrude from one side of the tube member 5.

After the short tube part 12 is formed on one side of the tube material 5, the upper and lower molds 22 and 23 are turned upside down with the tube material 5 still attached without disassembling the molds 22 and 23, and the above-described structure is formed in the lower mold 22. The short tube portion 12 can be formed on the other side using the same procedure. This state is shown in FIG. After completing the formation of the vertical short tube portions 12, 12 in this way, the upper die 23 is removed, the tube material 5 is turned 90 degrees, and the formed short tube portion 1 is removed.
2 and 12 are the lower mold 22 forming the relief hole 24.
Place the upper mold 23 so that it is located in the relief groove part, cover it again with the upper mold 23, and tighten it with the bolts 4, 4.
In the same procedure as above, the short pipe parts 12, 12 in the vertical direction are
When this happens, a cross tube is formed. This state is shown in FIG.

The above describes the formation of a single cross tube, but in the case of multiple rows of cross tubes as shown in FIG. It can be formed by doing the following.

In addition, the through holes 8, 8 for bulge processing of the molds 22, 23
The inner diameter of the short tube section forming piece 10 and the outer diameter of the short tube section forming piece 10 are dimensioned to provide sufficient clearance for the short tube section 12 to be squeezed out into the through holes 8, 8. Also, the draw rod 9
The coupling between the piece 10 and the bridge 10 can be achieved by using appropriate means such as bayonet coupling in addition to screws.

〔Effect of the invention〕

As explained above, the present invention provides a through hole for bulge processing on the tube material holding surfaces of a pair of molds that sandwich the tube material, and also provides a relief hole larger than the through hole at a position perpendicular to the through hole, In both types, the short tube section can be formed using the short tube section forming piece and the drawing rod, so when forming the short tube section in the top, bottom, left and right of the tube material, that is, in a cross shape, it is possible to form the short tube section in the 180 degree direction. This can be done by simply inverting the tube without removing it from the mold, and since the mold is removed only when molding in a 90 degree direction, the cross tube can be molded easily, quickly, and accurately, with a significant reduction in labor. can.
In addition, the quality is higher than when molding using hydraulic pressure, etc.
In addition, since low-cost molding can be performed, the manufacturing efficiency of cross tubes can be greatly improved.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a conventional bulge processing device, FIG. 3 is a cross-sectional view of a conventional cross tube forming device using a hydraulic press, and FIGS. 4 and 5 are cross-sectional views of a cross tube according to the present invention. FIG. 6 is a cross-sectional view showing the process of manufacturing by bulge molding, and FIG. 6 is a perspective view showing an example of the arrangement of the short pipe portions of the cross tube formed according to the present invention. 5...Pipe material, 6, 7...Pipe material holding surface, 8...Through hole for bulge processing, 9...Drawing rod, 10...Short pipe forming piece, 11...Preparation hole, 12...Short pipe Part, 2
2, 23...model, 24...relief hole, 25...operating plate.

Claims (1)

[Claims] 1. A pipe material 5 in which a single set or multiple sets of pilot holes 11, 11, . . . are bored in a cross direction for bulge processing.
The upper and lower molds 22 and 23 are sandwiched between the tube material holding surfaces 6 and 7 formed on the opposing surfaces of the upper and lower molds 22 and 23.
are connected with bolts 4, and a drawing rod 9 is inserted into the pilot hole 11 through one of the through holes 8 bored in the tube material holding surfaces 6 and 7 of these molds 22 and 23 so as to face each other, and the tip thereof is inserted into the tube material 5. A piece 10 for forming a short tube portion arranged inside
The drawing rod 9 is connected to a pressurizing device that drives it in the drawing direction, and by driving this, the lower short tube section 12 is formed, and then the upper and lower molds 22 and 23 are connected together. After reversing this and molding the short tube section 12 on the opposite side in the same manner as above, the upper and lower molds 22, 23 are disassembled, the tube material 5 is turned 90 degrees, and the formed short tube sections 12, 12 are are located in the relief holes 24, 24 between the mating surfaces of the upper and lower molds 22, 23, and the upper and lower molds 22, 23 are again bolted together, and the upper and lower short pipe parts 12,
12. A method for manufacturing a cross tube of a long tube, characterized in that a short tube portion in a cross direction is formed by performing the forming described in step 12. 2 Prepared holes 11 in the cross direction for bulge processing,
It has a pair of upper and lower molds 22, 23 having tube material holding surfaces 6, 7 for holding the tube material 5 having holes 11..., and through holes 8, 8 facing each other in the tube material holding surfaces 6, 7 of these molds. and an escape groove that forms escape holes 24, 24 with a larger diameter than the through hole 8 when the upper and lower molds 22, 23 are aligned in a direction perpendicular to the through hole, and the lower through hole 8 is provided. A drawing rod 9 is disposed so as to be freely inserted into the tube material 5, and its tip is formed so as to be freely connectable to a short tube forming piece 10 disposed within the pipe material 5, and a pressurizing device for driving the drawing rod 9 in the drawing direction is provided. Cross tube manufacturing equipment of connected long tubes.