JPH06297052A - Method and device for bulging and vehicle frame produced with bulging - Google Patents

Abstract

PURPOSE:To obtain a square tube by bulging a material to be bulged without deviating the position of a square corner. CONSTITUTION:The bulging device is provided with a pressurizing means 5 applying the working inner pressure on a material to be worked 1, a pressing means 4 applying the pressing force to the axial direction of the material to be worked, bulging dies 2, 3 and a back pressure loading movable die 8 being interposed between the material to be worked 1 and the bulging die 3. Then, the back pressure loading movable die 8 is pressed on the surface of the material to be worked 1 which is delayed in contact with the bulging dies 2, 3, the bulging method processing while applying the back pressure on the working surface is constituted with this back pressure loading movable die 8, and this is applied as the frame material of vehicles of an automobile, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bulge processing method and apparatus using a work material made of aluminum or an aluminum alloy, for example, a square tube, and a vehicle frame material produced by the bulge work.

[0002]

2. Description of the Related Art It has been considered to use a frame material made of aluminum or an aluminum alloy as a structural member for a frame structure in a vehicle such as an automobile, and as the weight of the frame material has been reduced in recent years, it has attracted more and more attention. There is.
FIG. 7 is a perspective view of a frame structure of an automobile body,
The cross-sectional shape of the structural member denoted by the reference numeral 70, which is a so-called center pillar, changes in the axial direction. Further, the tip portion is connected to the roof pillar 80 in a T-shape. Not only for such a frame structure of an automobile, but a structural member whose cross-sectional shape is changed in the axial direction is often used for a frame structure of a motorcycle or other vehicle.

In the case of forming a rectangular tube whose cross-sectional shape is changed in the axial direction, the conventional method of bulging a round tube is
(1) High pressure is required for molding. (2) It is necessary to have a large elongation property in the material of the tube. (3) It is difficult to obtain a square tube with perfect corners. There is a problem such as. Therefore, as a method for solving these problems, a method of bulging a tubular material having a rectangular cross section can be considered.

FIGS. 8 (a) and 8 (b) are a horizontal sectional view and a vertical sectional view of an apparatus for explaining a conventional method of bulging a rectangular tube as a workpiece. In this example, the upper and lower walls (long sides) are unchanged without changing the thickness of the side walls (short sides) of the square tube.
The square tube 1 as the material to be processed is sandwiched between the upper and lower molds 2 and 3 for bulge processing, and the seal caps 4 and 4 are arranged at both ends of the rectangular tube 1 in order to expand only To do. And
The fluid 5 is contained in the rectangular tube 1 and the internal pressure P for processing is applied, and the tube thickness of the side wall is not changed between the upper and lower molds 2 and 3.
A bulge molded product in which the upper and lower walls are expanded and expanded along the inner walls 2 ', 3'of the upper molds 2, 3 by plastic deformation to expand the cross-sectional shape in the axial direction. Is.

[0005]

In this case, the rectangular tube 1 is
It is an ideal state that the side wall 1b is expanded and expanded only by plastically deforming the upper and lower walls 1c, and the corners 1a are not displaced and expanded. However, the square tube 1 to be processed is delayed between the upper and lower molds 2 and 3 and the surface which is in contact with the inner walls 2 ′ and 3 ′ of the upper and lower molds 2 and 3 from the beginning or immediately after the processing. There is a surface (A) that contacts this, but when using the above-mentioned conventional means,
The surface that is in contact with the mold from the beginning and the surface that contacts first have much higher resistance to the die than the surface that contacts later (A). Therefore, as shown in FIG. 9A, the side wall 1b
First undergoes a large deformation and becomes a curved surface, and the corner portion 1 of the square tube 1
a is dragged, and as shown in (b) of the figure, the upper and lower walls 1c
Appear streaky on the outer surface of. Then, there is a problem that a large amount of stress is generated in the corner portion 1a, which makes molding difficult.

The problems in processing due to the difference in deformation resistance due to friction generated between the die and the material to be processed are not limited to the case of the square tube, but occur in the round tube and other tube materials. In addition to solving this problem, when the workpiece to be bulged is a square tube, a bulging method and an apparatus for expanding the bulging so that the corners do not shift are provided. An object of the present invention is to provide a frame material for vehicles such as automobiles, which is created by bulging.

[0007]

In order to achieve the above-mentioned object, the present invention, in expanding a work material by bulging, in the process of expanding the work material by applying a working internal pressure to the work material, The movable die for back pressure load is pressed against the surface (A) where the contact of the work piece with the bulging die is delayed, and the movable die for back pressure load allows processing while applying back pressure to the surface (A). A device for constituting a bulging method for applying and expanding a work material by bulging, which is a pressurizing means for applying a working internal pressure to the work material and a pressing force in the axial direction of the work material. A bulging device comprising a pressing means, a bulge forming die, and a back pressure load movable die interposed between the workpiece and the bulge forming die, and further, Material to be processed by the movable die for back pressure loading that is interposed between the material and the bulge forming die Axial cross section obtained by bulging the workpiece while applying back pressure to the surface (A) where the contact of the workpiece with the bulging die is delayed in the process of expanding by applying internal pressure for processing. A frame material for vehicles using a square tube having a different shape was constructed.

[0008]

[Function] By the above means, the bulge is formed while back pressure is applied to the surface (A) where the contact of the work piece with the bulge forming die is delayed, and the bulge forming die is contacted from the beginning or immediately after the processing. There is no difference in deformation resistance due to large friction as compared to the surface that is worn.

[0009]

Embodiments of the present invention will be described in detail below with reference to the drawings. 1A and 1B are a horizontal sectional view and a vertical sectional view of an apparatus for explaining a bulging method according to the present invention. A square tube 1 made of aluminum or an aluminum alloy as a material to be processed is sandwiched between upper and lower molds 2 and 3 for bulge processing, and seal caps 4 and 4 are arranged at both ends of the square tube 1. It From the inside of the rectangular tube 1, a fluid (water.
Apply an internal pressure of 5).

A space 6 between the upper and lower molds 2 and 3 for bulging and the side wall 1b of the square tube 1 to be expanded by the internal pressure for processing is constructed with a margin, and this space 6 is used for back pressure loading. The movable molds 8 and 8 are provided. The back pressure load movable dies 8 and 8 are supported by the lower die 3 such that the ends serving as fulcrums can be rotated within a predetermined range by pins 8a and 8a. Of the back pressure load movable mold 8,
Hydraulic or pneumatic cylinder 9 for applying back pressure to 8,
Have 9. FIG. 2 is a cross-sectional view showing a square tube 1 being bulged by the above-mentioned device. The surface (A) of the square tube 1 where the contact with the bulging dies 2 and 3 is delayed is used for back pressure loading. The movable molds 8 and 8 are pressed against each other, and processing is performed while applying back pressure (W) to the processing surface.

Adjustment of the back pressure of the movable dies 8, 8 for back pressure loading is as follows.
This is performed by a pressure control valve 10 such as a relief valve provided in the piping system of the cylinders 9, 9. The amount of back pressure applied to the upper and lower walls 1c of the square tube 1 by the load (W) applied by the cylinders 9 and 9 during the bulge forming using the bulge forming dies 2 and 3 is as follows. Without restraining the upper and lower walls 1c of 1 from being expanded, and (2)
By the bulge forming, the side wall 1b of the rectangular tube 1 is expanded and controlled to a size that prevents the corner portion 1a from breaking. Also, the speed of increasing the internal pressure P by the fluid is appropriately controlled.

3 (a), 3 (b) and 3 (c) are views showing a concrete example of performing bulge forming by using the bulge processing apparatus according to the present invention. A6N01S-T shown
4 aluminum alloy 60mm × 30mm square tube (2mmt), length
780 mm was used. The element pipe is sandwiched between upper and lower bulging dies having a back pressure load movable die through a lubricant, and seal mouths are arranged at both ends thereof. Pushing force F is applied to both ends of the seal base to seal between the base and the base pipe.
First, while exhausting from the exhaust port 4a of the left side cap, a fluid (water containing an anticorrosive) is injected from the right side cap to fill the inside of the raw pipe and close the exhaust port 4a. Next, the working internal pressure P for the fluid is gradually increased, and the back pressure W is applied to the back pressure loading movable die.
By applying a predetermined processing internal pressure P to the fluid while adding, the bulge processing is performed on the raw pipe. The maximum internal pressure P of the bulge processing equipment used in this case is 400 to 2000 kgf / c.
m ² and the average back pressure applied to the tube through the back pressure load movable die by the load (W) applied by the cylinder is 1
It is set to 00 to 500 kgf / cm ² . FIG. 3 (a) shows a bulge molded product 20 obtained from the square tube 1 as described above, and the dimensions after molding are 60 mm × 30 mm square × 2 mmt at both ends.
The maximum expansion section dimensions are 100 mm x 30 mm square, the length from both ends to the maximum expansion section is 520 mm, 80 mm, and the total length is 600 mm. The figure (b) shows the shape dimensions of both ends of the bulge molded product 20 and the figure (c) shows the geometry size of the maximum expanded portion of the bulge molded product 20. The phenomenon in which the corner portion 1a (see FIG. 1 (b)) of the rectangular tube 1 is dragged toward the upper and lower walls 1c surface side cannot be completely eliminated, but partially occurs. It was almost negligible compared to the case without pressure load.

The bulge molded product 20 thus obtained
Is cut at the position of its maximum expansion, and one end is 60 mm ×
30mm square x 2mmt, the other end is 100mm x 30mm square, length 520mm
7 is used as an automobile frame material such as a center pillar shown by reference numeral 70 in FIG. 7 as a rectangular tube whose cross-sectional shape is changed in the axial direction. In addition, as shown in FIG. 4, the bulge molded product 30 processed into a shape symmetrical in the axial direction with respect to the maximum expanded portion is used as the bulge molded product 30 at the position of the maximum expanded portion.
By dividing, two identical members can be created collectively. 5A and 5B show a hollow frame member 40 having fins 40 'formed on both sides of the lower wall and a hollow frame member 5 having fins 50' formed on both sides of the lower wall and having partition walls 50 ".
0 is shown, and both are suitable by applying the bulge processing shown in the above-mentioned Examples.

FIG. 6 shows an example in which a square tube to be a raw tube is bent and then bulged. In FIG. 6, (a) is a bulge molded product 60.
Is a front view, (b) is a side view thereof, (c) is an upper end view, (d) is a lower end view, and (e) is an AA sectional view. As described above, the bending process may be performed before the bulging process, but the bending process may be performed after the bulging process. In this case, when the cross-sectional structure as shown in (e) of the figure is used, a step is provided on the back pressure load movable die to form a partial recess. As described above, the bulge molded product that is formed by bending two-dimensionally or three-dimensionally in the axial direction according to the shape of the automobile body is appropriately used as a frame material for automobiles by taking advantage of its lightweight characteristics.

FIG. 10 shows that only one of the opposing walls 101, 101 of the rectangular tube 1 which is the raw tube shown in FIGS. 3 (a), (b) and (c) is stretched and deformed in the direction orthogonal to the axis. As expected, this is a specific example of a bulge processing apparatus suitable for pipe expansion in which the other opposing walls 102 and 102 do not grow. Movable mold for back pressure load 8
In the surface (see (b) of FIG. 1) in contact with the rectangular tube 1 of FIG. 1, a plurality of projections 8b are formed to be uneven surfaces, and the wall (102) surface on the side where expansion is not planned and the movable metal for back pressure load. The shapes of the molds 8 are meshed with each other, and the facing wall 10 located on this side
Molding is performed while constraining the deformation of 2,102. This makes it possible to deform and expand only one of the opposing walls 101, 101 without causing the other opposing walls 102, 102 of the rectangular tube 1 to stretch.

In the above embodiment, only one of the opposing walls 101, 101 of the square tube 1 is expanded, but the other opposing walls 102, 102 are also expanded slightly. It can also be applied in cases. Also in this case, naturally, the back pressure load movable die is disposed on the surface of the side that comes into contact with the bulge forming die later.

Further, in the above embodiment, the back pressure load movable die is constructed so as to be rotatable with respect to the bulge forming die, and the back pressure is applied by the cylinder arranged outside the bulge forming die. However, the present invention is not limited to this method, and other means may be used as long as back pressure can be applied to the surface where the contact of the work material with the bulge processing die is delayed. You can use it. For example, a flexible bag-shaped member may be used to apply liquid pressure to the bag-shaped member to provide back pressure.

[0018]

EFFECTS OF THE INVENTION According to the present invention having the above-described structure, since bulging is performed while applying back pressure to the surface of the work to be delayed in contact with the bulging die, the bulging is applied at the beginning or at the beginning. There is no large difference in resistance compared to the surface on which the corners of the square tube are dragged during processing. Therefore, the square tube to be bulged can be expanded without the corners being displaced, and can be molded with a good appearance. The rectangular tube, which is formed by the bulging process and whose cross-sectional shape is changed in the axial direction, can be effectively used such as being used as a frame material for vehicles such as automobiles.

[Brief description of drawings]

1A and 1B are a horizontal sectional view and a vertical sectional view of an apparatus for explaining a bulging method according to the present invention.

FIG. 2 is a sectional view showing a square tube being bulged by the method of the present invention.

3 (a), (b), (c) and (d) are shape diagrams showing specific examples of performing bulge forming using the bulge processing apparatus according to the present invention.

FIG. 4 is a perspective view showing an example of a bulge molded product obtained by the method of the present invention.

5 (a) and 5 (b) are perspective views showing an example of a bulging-processed shape member by the method of the present invention.

6 (a), (b), (c), (d) and (e) are explanatory views showing an example of a molded product which is subjected to bulging by the method of the present invention after performing bending. is there.

FIG. 7 is a perspective view of a space frame of an automobile body.

8A and 8B are a horizontal cross-sectional view and a vertical cross-sectional view of an apparatus for explaining a conventional method of bulging a rectangular tube.

9 (a) and 9 (b) are a perspective view and a sectional view showing an example of a bulge molded product obtained by a conventional method.

FIG. 10 is a partial cross-sectional view of an apparatus showing a preferred example of performing bulging by the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Square tube 1a ... Corner part 1b ... Side wall 1c ... Upper / lower wall 2,3 ... Bulge processing die 4 ... Seal mouthpiece 5 ... Fluid 6 ... Space 8 ... Back pressure load movable type 9 ... Cylinder 10 ... Control valve 20 ... Bulge molded product 30 ... Bulge molded product 40 ... Hollow shaped product 50 ... Hollow shaped product 60 ... Bulge molded product 70 ... Center pillar 80 ... Roof pillar

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kinya Usami 1-34-1 Kambara, Kambara-cho, Anbara-gun, Shizuoka Prefecture Within Nikan Corporation (72) Inventor Takashi Sasamoto 1-34 Kambara, Kambara-cho, Anbara-gun No. 1 Stock Company Nipparu Giken (72) Inventor Keiichi Sugiyama 1-34 Kambara, Kambara-cho, Anbara-gun, Shizuoka Prefecture

Claims (6)

[Claims] 1. A surface where contact of a work material with a bulge forming die is delayed in the process of expanding the work material by applying internal pressure for working to expand the work material by bulging.
A bulge processing method in which a movable die for back pressure load is pressed against (A), and processing is performed while applying back pressure to surface (A) using this movable die for back pressure load. 2. A device for expanding a work material by bulge processing, comprising: pressurizing means for applying a working internal pressure to the work material; and pressing means for applying a pressing force in the axial direction of the work material.
A bulging device comprising a bulging die and a back pressure load movable die interposed between the work material and the bulging die. 3. The movable die for back pressure loading is configured to be rotatable with respect to a bulging die, and a back pressure is loaded by a cylinder arranged outside the bulging die. The bulge processing apparatus according to claim 2. 4. A bulge of the work material in the process of expanding the work material by applying a working internal pressure to the work material by a movable die for back pressure loading provided between the work material and the bulging die. A frame material for vehicles that uses a rectangular tube with a cross-sectional shape that changes in the axial direction, obtained by bulging the material to be processed while applying back pressure to the surface (A) where the contact with the processing die is delayed. 5. The vehicle frame according to claim 4, wherein the square tube whose cross-sectional shape is changed in the axial direction is obtained by dividing a square tube that is bulged so that the central portion bulges. Material. 6. The vehicle frame material according to claim 4 or 5, wherein the bent rectangular tube is bulged to change the cross-sectional shape in the axial direction.