JP3002765B2 - Method of manufacturing bent plate material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention is to mold the pipe into a flat shape, a process for producing the required bending is performed folded plate material in the thickness direction.

[0002]

2. Description of the Related Art Conventionally, it has been common to manufacture various products by joining a long rectangular solid plate material bent into a required shape and other members by means such as welding. It is being done. For example, FIG. 8 shows a grill guard 25 attached to the front part of the body of a four-wheel drive vehicle,
Plate members 21, 21 formed in required shapes are joined to both ends of a pair of horizontal rods 22, 22 which are vertically separated by a required interval, and a U-shaped member 23 is provided outside the respective plate members 21 on the grill of the automobile. Are joined together. A bent plate material 20 having a required width and bent along the outer peripheral edge thereof is joined to each of the plate materials 21 formed into a required shape by welding.

[0003]

The bent plate material 20
Is exposed to the outside as shown in FIG.
It is necessary to chamfer both edge portions 20a, 20a in the width direction, and there is a disadvantage that the number of processing steps increases and the cost increases. Further, it is pointed out that the thickness of the plate 20 becomes large in order to obtain required steel properties because a solid plate is used, and the grill guard 25 itself becomes heavy. Further, when the plate 21 is joined to the back surface of the bent plate 20 by welding, there is a problem that thermal deformation (distortion) occurs due to welding heat and "burn" due to high heat occurs on the front side of the bent plate 20. This "burn" remains as it is even after electropolishing is performed in the subsequent step to prevent glaze and oxidation of the welded portion, resulting in a loss of commercial value.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has been proposed in order to solve the above-mentioned problems. The present invention aims to reduce the weight and to prevent "distortion" and "burn" during welding. and to provide a method for manufacturing a bent plate material.

[0005]

[0006]

[0007]

[Means for solving the problems] To overcome the above-mentioned problems,
In order to suitably achieve the intended purpose, the method for manufacturing a bent plate material according to the present invention includes pressing a pipe in the radial direction to form an elliptical pipe having a substantially elliptical cross section, A core material set to a width substantially the same as the internal width of the pipe is inserted, and the elliptical pipe inserted with the core is further pressed in the radial direction to form a hollow plate holding the core. ,
A portion of the hollow plate where the core is inserted is bent in the thickness direction of the plate.

[0008] In order to suitably achieve the intended purpose, the present application
The method for manufacturing a bent plate material according to another invention is such that the pipe is pressed in the radial direction to form an elliptical pipe having a substantially elliptical cross section, and the elliptic pipe has substantially the same internal width as the pipe. The core material set to the width dimension is inserted, and the elliptical pipe inserted with the core material is further pressed in the radial direction to form a hollow plate material sandwiching the core material. The inserted portion is bent in the thickness direction of the plate material, and then the core material (11) is removed from the hollow plate material (18).

[0009]

EXAMPLES Next, a method for producing a bent plate member according to the present invention, by way of preferred embodiments, with reference to the accompanying drawings, hereinafter will be described in detail. FIG. 1 is an explanatory view showing a step of forming a hollow plate 18 by pressing a thin long cylindrical pipe 10 in a radial direction, and further forming a hollow bent plate 19 by bending the hollow plate 18. It is. Also, FIG.
FIG. 3 is a partially cutaway perspective view showing a bent portion 18a of the hollow bent plate material 19, and FIG.
FIG. 4 is a perspective view showing an example of forming a hollow bent plate material 19 by bending the hollow plate material 18. FIG. 1A is a perspective view showing a thin and long cylindrical pipe 10 used in the present embodiment. The diameter D and the length of the pipe 10 are the width W and the desired width W of the hollow plate 18. It is determined by the length L.

In order to form the hollow plate 18 from the pipe 10, first, the upper die 12 of the press 14 shown in FIG.
In a state where the pipe 10 is positioned between the lower mold 13 and the lower mold 13, the two molds 12 and 13 are brought close to each other and the pipe 10 is pressed in the radial direction. At this time, the pipe 10 is not formed into a flat shape at once, but as shown in FIG. 3 (b), the pressing process is interrupted at the stage when the cross section is deformed into a substantially elliptical shape.

The inner width of the elliptical pipe 10A whose cross section has been deformed into an elliptical shape (dimension on the long axis side)
Then, a rectangular core material 11 set to have substantially the same width dimension as that described above is inserted. This core material 11 is not required over the entire length of the elliptical pipe 10A, and as shown in FIG. 1C, a hollow bent plate material 19 obtained by bending a hollow plate material 18 described later. May be located only in the portion to be bent 18a (the portion to be bent). Also, the length of the cored bar 11,
The dimensions such as the thickness are determined by an appropriate length depending on the spacing of the space of the hollow plate member 18 and the bending conditions such as the bending angle and the bending radius of the bent portion 18a, and the material is not particularly specified. However, if rust due to oxidation is taken into account, stainless steel is preferable.

After the core material 11 is positioned at the bent portion of the elliptical pipe 10A, as shown in FIG. 3C, when the core material 11 is further completely pressed in the radial direction by the press machine 14, as shown in FIG. The hollow plate 18 as shown in FIG. As described above, the bent portion (18a) of the hollow plate member 18 includes:
Since the core material 11 is interposed, no space is provided, but a constant space 19a is defined in other portions in the width direction. Since the both end portions 18b, 18b in the width direction of the hollow plate 18 obtained in this manner have an appropriate curved surface, it is possible to omit the work of chamfering in a later step. In addition, since two plate members are stacked, a desired rigidity can be obtained with a thin material, and the weight can be reduced. Note that the surfaces of the upper mold 12 and the lower mold 13 that abut on the pipe 10 shown in FIG. 3 are slightly curved surfaces, and therefore, as shown in FIG. However, this is not an essential requirement and may be a simple flat shape. In the embodiment, the pressing of the pipe 10 is performed by a press machine. However, the pressing may be performed by using a roll or the like without using the press machine.

Next, the bending process for forming the hollow bent plate member 19 from the hollow plate member 18 will be described. FIG. 4 shows an example in which the hollow plate 18 is bent. In this embodiment, the bending is performed by a bender. That is, as shown in FIG. 4A, the bending shaft 15 of the bender 16 is held in a state where one end 18c in the longitudinal direction of the hollow plate 18 is held by an appropriate jig (not shown).
The part to be bent of the hollow plate 18 is brought into contact with the hollow plate 18. Then, the end side 18 of the hollow plate 18 opposite to the holding side.
The hollow plate 18 is bent at a required angle in the plate thickness direction along the bending axis 15 by urging d from the side by a bending jig (not shown). In addition, as the bending shaft 15, a corresponding one is selected and mounted depending on conditions such as a desired bending angle and a bending radius.

FIG. 2 is a perspective view showing the bent portion 18a of the hollow bent plate material 19 obtained by the above-described manufacturing method in a partially broken state. As described above, the core material 11
It is not necessary to cover the entire length of the hollow bent plate member 19 (hollow plate member 18), and it is sufficient that the core member 11 is inserted only in the bent portion 18a. It is determined by the material, bending angle and bending radius.

Here, when the plate material is bent, a tensile stress is applied to the outer portion of the bent portion and a compressive stress is applied to the inner portion. In particular, in the case of the hollow plate material 18 having the space 19a, these stresses are applied. Because the stress difference of
The outer portion may not be able to withstand the tensile stress and cause cracks, or the inner portion and both ends may have "wrinkles" due to compressive stress. Further, since the outer portion is displaced inward and the inner portion is displaced outward, the outer portion and the inner portion come into contact with each other, and a fixed space is not formed in the bent portion 18a. Therefore, when another member is welded to the bent portion 18a, "burn" due to welding heat is expected to occur on the surface side as described above.

However, as described above, since the core member 11 is inserted into the bent portion 18a of the hollow bent plate member 19 of the embodiment within a required range, it is as if the bent portion 18a is solid. Stress can be distributed like a plate material. That is, the occurrence of cracks in the outer portion 19B and “wrinkles” in the inner portion 19A can be suitably prevented. Accordingly, in the case where the hollow plate 18 is curved in the plate width direction as shown in FIG. 6, the same curvature in the plate width direction can be favorably held at the bent portion 18a without impairing the curvature. be able to. Also,
The space between the outer portion 19B and the inner portion 19A is maintained the same as before the bending by the thickness of the inserted core material 11.

The hollow bent plate member 19 formed from the hollow plate member 18 by the above-described manufacturing method is used for the grill guard 25.
, It is possible to suitably cope with a case where other members are joined by welding or the like. FIG. 5 is a partially cutaway perspective view showing a state in which the plate 27 is joined to the inner portion 19A of the hollow bent plate 19 by welding, and reference numeral 26 denotes a bead formed by welding. As described in the prior art, when welding other members to a solid plate material, the occurrence of `` burn '' due to high heat on the back surface of the welding surface and the thermal deformation (distortion) due to the temperature difference between the welding surface and the back surface. What happened was a drawback. However, when the plate material 27 is welded to the back surface (inner portion 19A) of the hollow bent plate material 19 formed by bending the hollow plate material 18, the space 1
9a becomes the heat insulating layer, so that the welding heat is
Since it is not conducted to B, the temperature of the outer portion 19B does not become high, and the occurrence of thermal deformation (distortion) and "burn" can be reliably prevented.
In the bent portion 18a, although the core material 11 is interposed, since the material is different from the hollow plate material 18 or is a separate member, the heat conductivity is different and the outer portion 19a is different.
Thermal influence on B can be minimized and thermal deformation
(Distortion) and occurrence of "burn" can be prevented.

In the embodiment, the core material 11 is kept inserted in the bent portion 18a of the hollow bent plate material 19. However, the core material 11 is removed after the hollow plate material 18 is bent. As shown in FIG. 7, a space 19b in the thickness direction may be defined also in the bent portion 18a. in this case,
The weight of the hollow bent plate member 19 can be reduced. In addition, the space 19b in the bent portion 18a functions as a heat insulating layer, so that the occurrence of thermal deformation (distortion) and "burn" during welding can be reliably prevented. The material of the core material 11 is selected from those which exhibit a solid phase during bending and can be easily removed as a liquid phase by a required chemical treatment or heat treatment.

Although the embodiment has been described with respect to the case where the hollow bent plate is used as a member constituting a grill guard for an automobile, the present invention is not limited to this.
Of course, it can be applied to various products.

[0020]

As has been described in the foregoing, according to the method of manufacturing a hollow bent plate material according to the present invention, since the bent portion of the hollow plate are interposed the core material,該折bend during bending Cracks and "wrinkles" can be effectively prevented. Ma
Also, when welding another member to the back side of the hollow bent plate material,
"Burning" and thermal deformation (distortion) due to welding heat do not appear on the front side of the hollow bent plate material, and a plate material with high commercial value can be provided. Further , the weight can be reduced by removing the core material from the bent portion.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a step of forming a hollow plate by pressing a pipe to form a hollow plate, and further forming a hollow bent plate by bending the hollow plate;

FIG. 2 is a perspective view showing a partially bent portion of a hollow bent plate material.

FIG. 3 is an explanatory view showing a process of processing a pipe into a hollow plate material.

FIG. 4 is a perspective view showing an example of forming a hollow bent plate material by bending a hollow plate material.

FIG. 5 is a partially broken perspective view showing a state in which the plate member is joined to an inner portion of the hollow bent plate member by welding.

FIG. 6 is a perspective view showing a main part of the hollow bent plate material.

FIG. 7 is a cross-sectional view illustrating a main part of a hollow bent plate material obtained by removing a core material from a bent portion.

FIG. 8 is a perspective view showing an example of a grill guard mounted on a front portion of a vehicle body of a four-wheel drive vehicle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pipe 10A Elliptic pipe 11 Core material 18 Hollow plate material 18a Bending part 19a Space 19b Space

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-1417 (JP, A) JP-A-3-297519 (JP, A) JP-A-5-200437 (JP, A) 18264 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21D 9/05 B21C 37/15 B21D 51/00 B21D 53/86 B60R 19/52

Claims (2)

(57) [Claims] 1. A pipe (10) is pressed in a radial direction to form an elliptical pipe (10A) having a substantially elliptical cross section, and the elliptical pipe (10A) has an internal width dimension of the pipe (10A). A core material (11) having the same width as that of the core material (11) is inserted. The hollow plate (18) is formed, and a portion (18a) of the hollow plate (18) in which the core (11) is inserted is bent in the thickness direction of the plate (18). Method of manufacturing bent plate material. 2. The pipe (10) is pressed in the radial direction to form an elliptical pipe (10A) having a substantially elliptical cross section, and the elliptic pipe (10A) has an internal width dimension of the pipe (10A). A core material (11) having the same width as that of the core material (11) is inserted, and the elliptic pipe (10A) inserted with the core material (11) is further pressed in the radial direction to pinch the core material (11). The hollow plate material (18) is formed, and a portion (18a) of the hollow plate material (18) where the core material (11) is inserted is bent in the thickness direction of the plate material (18), and then the core material is bent. (11) A method for manufacturing a bent plate material, wherein (11) is removed from the hollow plate material (18).