JP2982030B2 - Case forming method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a case, and more particularly to a method and an apparatus for forming a case formed by bending a single metal plate to form a rectangular tube. is there.

[0002]

2. Description of the Related Art As such a conventional case, there is one described in Japanese Patent Publication No. 1-19881.
An example is shown below. In FIG. 11, a case is formed by bending a single metal plate into a rectangular tube shape to form an upper surface 1, a lower surface 2, left and right side surfaces 3 and 4, and an outer-folded flange 5 at one end. The bent metal plates are overlapped on the upper surface 1 and spot-welded. It should be noted that a stepped portion 6 having a thickness substantially equal to the plate thickness is formed on one side of the overlapped portion so that the outside of the overlapped portion becomes a flat surface. Notch holes 7 and 8 are formed in the upper surface 1, and notch holes 9 and 10 are formed in the lower surface 2.

[0003] In the case configured as described above, since one metal plate is bent, the number of components can be reduced, and the number of spot welding points is reduced, so that the processing time and the processing cost can be reduced.

[0004]

However, according to such a configuration, a stepped portion 6 having a thickness substantially equal to the thickness of one side of the overlapped portion is formed such that the outside of the overlapped portion becomes a flat surface.
Is formed inward, so that the volume of the case is reduced only by the stepped portion. In designing such an internal unit housed in the case, the stepped portion 6 protruding into the case must be avoided, and the degree of freedom is limited. In some cases, a stepped flange is provided at the end for both strength reinforcement and decorativeness. However, a stepped flange is formed at the end by bending one metal plate sequentially. It has been considered difficult to form the case in the past, and a flange formed as a separate member in advance is fixed to the opening of the case together with a reinforcing piece for reinforcing the corner portion by spot welding, There is a problem that the number of parts increases and the number of work steps increases.

An object of the present invention is to solve such a conventional problem. One of the objects of the present invention is to provide a rectangular tubular case having a stepped flange at one end without a stepped portion protruding inside. It is an object of the present invention to provide a forming method of bending a metal plate. It is another object of the present invention to provide a bending device used for bending a rectangular tubular case having a stepped flange at one end.

[0006]

According to a method of forming a case which solves such a problem, a metal plate having parallel sides orthogonal to each other is provided on a first parallel side of a concave portion so as to fit each other. A first step of punching into a shape in which a plurality of concave and convex portions in which the lower portion of the convex portion (the lower portion of the convex portion) is smaller than the lower portion of the concave portion (the upper portion of the convex portion); The second in which the side of the first is bent into a crank shape to form a stepped flange
And a third step of bending the metal plate inward by 90 degrees to form each of the upper, lower, left, and right surfaces of the case so that one side of the uneven portion overlaps the other side of the uneven portion, It is characterized in that it is formed in a fourth step of fitting and fixing the uneven portions formed on the first parallel side to each other.
A bending device that bends a metal plate having parallel sides perpendicular to each other to form a rectangular cylindrical case having a stepped flange at one end has a V-shaped tapered surface corresponding to the bending angle at the tip. Punch, a V-shaped tapered surface corresponding to the bending angle, a die holder provided with a pad movably supported by an elastic member in a central concave portion, and a stepped portion into which a stepped flange portion is fitted. And a die that rotates according to the tapered surface of the die holder while moving the pad according to a change in the distance from the punch, the die being formed of two die pieces rotatably connected via a rotary shaft. It is characterized by the following.

[0007]

According to the case forming method of the first aspect of the present invention,
By bending one metal plate, a rectangular cylindrical case having a stepped flange at one end can be formed. According to the apparatus for manufacturing a case according to the second aspect of the present invention, a metal plate having one side bent in a crank shape so as to form a stepped flange at one end of a rectangular cylindrical case can be bent into a rectangular cylindrical shape. it can.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view of the principle configuration of a case formed by the method of the present invention. In the figure, a case is formed in a rectangular tube shape having an upper surface 11, a lower surface 12, a left side surface 13, and a right side surface 14 by bending a single metal plate having parallel sides perpendicular to each other. The first parallel sides 15 and 16 of the metal plate are provided with a plurality of wedge-shaped uneven portions whose upper part of the concave part (lower part of the convex part) is smaller than the lower part of the concave part (upper part of the convex part) so as to fit each other. They are continuously formed by punching in the direction, and these concave and convex portions are fitted and fixed to each other. In FIG. 1, the upper surface 11 is the surface on which the concave and convex portions are fitted and coupled, but the coupling surface is not limited to the upper surface. In bending such a case, for example, a known bending device disclosed in the above-mentioned publication can be used.

Focusing on the connecting portion of the case configured as described above, the connecting of the concave and convex portions is performed only by the thickness of the metal plate, and both the front and back are flat. That is, unlike the conventional structure in which the stepped portion 6 and the flat surface are overlapped, the stepped portion 6 does not protrude inside, and the volume inside the case can be increased accordingly. Further, in designing the inner unit housed inside the case, it is not necessary to consider a protruding portion to the inside, which facilitates the design. Note that the strength of the case for accommodating the instrument is sufficient only by fitting such uneven portions, but spot welding may be performed near both ends of the connecting portion as necessary.

FIGS. 2 and 3 show a specific embodiment of the case of FIG. In FIG. 2, one side of the second parallel side of the metal plate is bent at one end of the case as a stepped flange 17, and the other side of the second parallel side is bent and formed as an inward flange 18 at the other end. Have been. Here, the stepped flange 17 functions to enhance the decorativeness and the strength, and the inwardly-folded flange 18 functions as a back surface for locking the back surface of the inner unit housed in the case and functions to increase the strength. I do. The method for forming the case shown in FIG. 2 and its apparatus will be described separately.

In FIG. 3, an outer folding flange 19 is formed at one end of the case. This outer folding flange 19
Functions to form the front surface of the case and increase strength. As a method and an apparatus for forming the case shown in FIG. 3, for example, the method and apparatus disclosed in the above-mentioned publication can be used except for the fitting step of the connecting portion. The combination of the folding directions of the flanges is not limited to these examples, but can be appropriately changed depending on the application.

A method for forming the case shown in FIG. 2 according to the present invention will be described. FIG. 4 is a simplified development view of a metal plate in an intermediate step of forming the case of FIG. As is apparent from the figure, the first parallel sides 15 and 16 of the metal plate have a wedge-shaped upper portion of the concave portion (lower portion of the convex portion) smaller than a lower portion of the concave portion (upper portion of the convex portion) so as to fit each other. A plurality of uneven portions are continuously formed by punching in the thickness direction.

First, in a first step, a metal plate having parallel sides 15, 16 and 17, 18 orthogonal to each other is placed in a first step.
The parallel sides 15 and 16 are formed with a plurality of concavities and convexities in which the upper part of the concave part (the lower part of the convex part) is smaller than the lower part of the concave part (the upper part of the convex part) so as to fit each other. In the second side 18 of the parallel side, a plurality of inverted trapezoids t are formed such that the middle point of the lower side is located at the end of the virtual bending line a to d of each of the surfaces 11 to 14 of the rectangular cylinder. Punch out. When the inward flange is not formed, punching of a plurality of inverted trapezoids t is unnecessary.

Next, in a second step, the first side 17 of the second parallel side of the metal plate is bent into a crank shape to form a stepped flange, and in a third step, the second parallel side of the second parallel side is formed. The second side 18 is bent at right angles in a direction opposite to the first side 17 to form an inward flange. The bending line of the inward flange is provided inside the lower side of the inverted trapezoid t. Thereby, the strength around the inward flange after being bent into a rectangular cylindrical shape can be increased. Note that these second
The step and the third step may be interchanged. FIG. 4 shows a state in which the steps up to the third step have been completed in this way. When the inward flange is not formed, the bending step can be omitted.

In a fourth step, one of the first parallel sides 15 and 16 is bent inward by 90 degrees along folding lines a to d having the middle point of the lower side of the inverted trapezoid t as an end. The upper, lower, left and right surfaces 11 to 14 of the case are set such that the side (for example, 16) overlaps the other uneven portion side (for example, 15).
To form In this step, since the stepped flange 17 is bent in a right angle direction, an apparatus described later is used.

Then, in a fifth step, the concave and convex portions formed on the first parallel sides 15 and 16 overlapped with each other are fixedly fitted to each other.

FIGS. 5 and 6 are explanatory views of the main parts of an apparatus used for bending the stepped flange 17 in a right angle direction in the fourth step. In the figure, reference numeral 21 denotes a punch, and a V-shaped tapered surface corresponding to the bending angle is formed at the tip. Reference numeral 22 denotes a die holder, which has V-shaped tapered surfaces 23 and 24 corresponding to the bending angle, and a central recess 25 provided with a pad 27 supported by an elastic member 26 made of, for example, a spring so as to be movable in the vertical direction. ing. Reference numerals 28 and 29 denote die pieces, and stepped portions 30 and 31 into which the stepped flange portions 17 of the metal plate are fitted.
Are formed and are rotatably connected via rotation shafts 32 and 33. An arc portion R is provided at a corner of each of the die pieces 28 and 29 in contact with the pad 27 so as to be able to rotate smoothly with respect to the pad 27. Reference numerals 34 to 37 denote springs for urging the die pieces 28 and 29 so as to keep them horizontal when the punch 21 is raised. One end of each of the springs 34 to 37 is locked by each of the die pieces 28 and 29, and the other end is locked by the die holder 22. 3
Reference numerals 8 and 39 denote support plates arranged so as to sandwich the end faces of the die pieces 28 and 29, and are provided with guide grooves 40 and 41 for guiding the rotating shafts 32 and 33 in the vertical direction. P represents the center of the rotation shafts 32 and 33.

In such a configuration, when the punch 21 is raised, the die pieces 28 and 29 are kept horizontal by the springs 34 to 37. In contrast,
When the punch 21 is lowered, the die pieces 28 and 29 rotate according to the tapered surfaces 23 and 24 of the die holder 22 while pushing down the pad 27 against the bias of the springs 34 to 37 and the elastic member 26. The same is true even if the punch 21 is fixed and the die holder 22 is moved in the vertical direction.

FIG. 7 is an explanatory view of a bending step using such an apparatus. Start of bending The tip of the punch 21 hits the metal plate M to be bent. During bending, the metal plate M is sandwiched between the tip of the punch 21 and the die pieces 28 and 29, and the die pieces 28 and 29 push down the pad 27 around the rotation shafts 32 and 33 while the die holder 2 is pressed down.
2 according to the second tapered surfaces 23 and 24. The bending is completed. The die pieces 28 and 29 are the tapered surface 2 of the die holder 22.
It rotates to the position corresponding to 3, 24 and stops. As a result, the metal plate M is pressed by the punch 21, the die pieces 28 and 29, and the tapered surfaces 23 and 24 of the die holder 22, and is bent at a predetermined angle (90 degrees). Then, by raising the punch 21, the die pieces 28 and 29 and the pad 27 return to the initial state by the bias of the springs 34 to 37 and the elastic member 26.

Here, the function of the rotating die pieces 28 and 29 will be described. The rigidity of the stepped flange 17 portion of the metal plate M is increased with respect to the bending in the fourth step, and the rigidity becomes uneven with other flat plate portions. Therefore, for example, when the metal plate M is bent in combination with a punch using a die corresponding to only the die holder 22 without providing the die pieces 28 and 29, the metal plate M follows the bending up to the top surface of the tapered surface of the die, but the top surface is bent. The excess portion does not follow the bending, resulting in uneven folding, and as a result, the outer portion is bent outside at the contact portion with the corner of the top surface. However, the die piece 2 that rotates following the bending of the punch 21 as in the apparatus of the present invention.
By providing 8, 29, folding unevenness due to uneven rigidity is eliminated, and stable folding can be realized.

As shown in FIG. 8, the order in which the upper surface 11 is formed first is as follows.
Bend lines a and d near the parallel sides 15 and 16 of the upper surface 11 and then the left side surface 13 adjacent to the short surface 11a of the upper surface 11
The bending line b is bent so as to rise, and finally the bending line c is bent so as to rise the right side surface 14 adjacent to the long surface 11b of the upper surface 11. In the state where the bending line c is bent, the uneven portion of the long surface 11b of the upper surface 11 overlaps the uneven portion of the short surface 11a as shown by a two-dot chain line.

The case where the upper surfaces 11 overlap as described above is set in, for example, the device shown in FIG.
5 and 16 are pressed and fitted to each other. In the figure,
(A) shows the side and (b) shows the front. 42
A punch 43 has a flat end, and a die 43 has a flat top. The die 43 is formed in a cantilever shape, and the width of the upper part thereof is set to the bending width of the case as a guide dimension. Reference numerals 44 and 45 denote cylinders for pressing the side surfaces 13 and 14 of the case against the side surface of the die 42. Reference numeral 46 denotes a receiving block for supporting the other end of the die 42. When attaching and detaching the case, the receiving block 46 is slid by a cylinder (not shown) via a shaft 47 so as to open the other end of the die 42. Reference numeral 48 denotes a case discharge block, which is slid in a direction of discharging the case from the die 42 via a shaft 49 by a cylinder (not shown) or the like.

When the first parallel sides 15 and 16 of the case are pressed and fitted to each other in the concave and convex portions, the upper surface 11 is held in a state where the receiving block 46 is slid and the other end of the die 42 is opened.
The case is inserted into the die 43 with the side facing upward, and positioning is performed. Next, the side surfaces 13 and 14 of the case are pressed and fixed to the side surfaces of the die 42 by operating the cylinders 44 and 45. next,
The punch 42 is lowered while the receiving block 46 is slid so as to support the other end of the die 42, and the upper surface 11 of the case is pressed against the upper surface of the die 42. Thereby, the concave and convex portions of the first parallel sides 15 and 16 are fitted to each other. Thereafter, the case discharge block 48 is slid while the receiving block 46 is slid to open the other end of the die 42, and the case is discharged from the die 42. Most of the series of steps of the press fitting of the concave and convex portions by such an apparatus can be automated by sequence control or the like, and labor can be saved.

Most of the steps for bending the case as shown in FIGS. 1 and 3 can be automated by using an apparatus as shown in FIG. 10, for example. In the drawing, (a) shows a state before the metal plate M is bent, (b) shows a state where the first parallel sides 15 and 16 forming the upper surface 11 are bent at a right angle in the same direction, and (c). Indicates a state in which the central portion is bent at a right angle in the same direction so as to form the bottom surface 12 and the left and right side surfaces 13 and 14.

Reference numerals 50 to 52 denote pressing blocks for positioning the bent portion by pressing the metal plate M. The width of the pressing surface of the metal block 50 is set equal to the width of the bottom surface 12 of the case. Numerals 53 to 56 denote rotating blocks which press the metal plate M against the side surfaces of the respective pressing blocks 50 to 52 by turning by 90 degrees and bend them at right angles.

In the state (a), the holding blocks 50 to 52 are raised, the rotating blocks 53 to 56 are set at the initial position, and the metal plate M is placed in the rotating block 53 in a predetermined positional relationship.
Set on ~ 56. In the state (b), the metal plate M is held by the holding blocks 50 to 52.
And presser block 5 so as to be sandwiched between rotary blocks 53 to 56.
0 to 52 are lowered and fixed, and the rotating blocks 53 and 56 are fixed.
Is rotated upward by 90 degrees, and the first parallel sides 15 and 16 forming the upper surface 11 are bent at a right angle in the same direction. In the state of (c), the metal plate M is held by the holding blocks 51, 52.
Is raised to a position where there is no problem in bending the side surfaces 13 and 14 of the metal plate M, the rotating blocks 53 and 56 are returned to the initial positions, and the rotating blocks 54 and 55 are moved upward by 90 degrees.
The base 12 and the left and right side surfaces 13 and 14 are formed by rotating them by degrees. At this time, the rotating block 54 is rotated before the rotating block 55. Thereby, the side 1 is placed on the side 15
6 overlap. Thereafter, as shown in FIG.

According to the apparatus shown in FIG. 10, the metal plate M can be bent and formed into a rectangular tube only by setting the metal plate once, and the number of working steps can be reduced.

In the above-described embodiment, an example is shown in which the fitting concave and convex portions are formed in a straight wedge shape, but they may be formed in a curved wedge shape.

Further, in the above embodiment, a device in which the opposing surface of the rotating die piece is formed flat is used as a device for bending the stepped flange in the right-angle direction, but as shown by a broken line in FIG. It is also possible to use a comb-shaped member that is formed in a comb-like shape so as to be fitted to each other, and a sliding portion with the die piece is formed in an arc shape. Thereby, since the left and right die pieces are fitted to each other throughout the bending process, a stable bending operation can be obtained.

[0030]

As described above, according to the present invention,
A square tubular case with a large volume in which the stepped portion does not project inside can be obtained. Here, according to the present invention, a plurality of wedge-shaped plural portions in which the upper portion of the concave portion (the lower portion of the convex portion) is smaller than the lower portion of the concave portion (the upper portion of the convex portion) so as to fit into the first parallel sides 15 and 16 of the metal plate. The irregularities are continuously formed by punching in the thickness direction, and these irregularities are fitted together and fixed, so that the metal plate is partially thinned to form the irregularities. In comparison, the workability is excellent, and the assembled case does not have unevenness in the plate thickness direction, so that the flatness is high and the appearance is good. In addition, a rectangular cylindrical case having a stepped flange at one end can be formed by bending a single metal plate, and a case with a small number of parts and a high strength can be realized with a small number of man-hours. Furthermore, since a bending device having a rotating die pad is used in bending and forming a rectangular cylindrical case having a stepped flange at one end, it can be bent stably.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the principle configuration of the invention of claim 1;

FIG. 2 is a specific embodiment of the case of FIG. 1;

FIG. 3 is a specific embodiment of the case of FIG. 1;

FIG. 4 is a simplified development view of a metal plate in an intermediate step of forming the case of FIG. 2;

FIG. 5 is an explanatory diagram of a main part of an apparatus used for bending a stepped flange in a right angle direction in a fourth step of forming the case of FIG. 2;

FIG. 6 is an explanatory diagram of a main part configuration of FIG. 5;

FIG. 7 is an explanatory view of a bending step using the apparatus of FIG.

FIG. 8 is an explanatory view of the order in which the case of FIG. 2 is bent into a rectangular tube shape in a fourth step.

FIG. 9 is a configuration explanatory view of an example of an apparatus that uses uneven portions of a case for press fitting.

FIG. 10 is a configuration explanatory view of an example of an apparatus used for bending the case of FIGS. 1 and 3;

FIG. 11 is a configuration explanatory view showing an example of a conventional case.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 top surface 12 bottom surface 13, 14 side surface 15, 16 first parallel side 17 stepped flange 21 punch 22 die holder 23, 24 tapered surface 25 central recess 26 elastic member 27 pad 28, 29 die piece 30, 31 stepped portion 32, 33 Rotating shafts 34, 35 Springs 38, 39 Support plates 40, 41 Guide grooves

Claims (2)

(57) [Claims] 1. A metal plate having parallel sides orthogonal to each other,
The first parallel side is punched into a shape in which a plurality of concavo-convex portions in which the upper portion of the concave portion (the lower portion of the convex portion) is smaller than the lower portion of the concave portion (the upper portion of the convex portion) are continuously formed so as to fit each other. A first step, a second step of bending a first side of the second parallel side of the metal plate into a crank shape to form a stepped flange, and bending the metal plate inward by 90 degrees each to form one side. A third step of forming the upper, lower, left, and right surfaces of the case so that the side of the uneven portion overlaps the side of the other uneven portion; and the uneven portion formed on the first parallel side is fitted to each other. And forming a case. 2. A bending device for bending a metal plate having parallel sides perpendicular to each other to form a rectangular cylindrical case having a stepped flange at one end, wherein a V-shaped taper corresponding to a bending angle is provided at a tip portion. Formed punch, V-shaped tapered surface corresponding to the bending angle is formed, Die holder provided with pad movably supported by an elastic member in the central recess, Stepped flange portion fits A die that has two step pieces formed with a stepped portion and rotatably connected via a rotating shaft, and that rotates according to the tapered surface of the die holder while moving the pad according to a change in distance from a punch;
And a folding device.