JP2001096325A - Method of manufacturing sheet metal case and manufactured sheet metal case - Google Patents

Abstract

(57) [Problem] To provide a method of manufacturing a sheet metal case having no through hole in a manufactured case without largely changing a conventional manufacturing method. SOLUTION: A rectangular metal plate 11 such as SPCC is prepared, and one side 11a of two adjacent sides of the metal plate 11 is provided.
A cut 13 is made along the bending line 12a at the symmetrical position on both sides thereof, and one side has a cylindrical bag-like projection 14 having a bottom.
The other side is formed with a hole 15 to be fitted into the bag-shaped projection 14. One side 11a is bent inward at a right angle along the bending line 12a, and then the outer portion 11c of the cut 13 is bent at the bending line. 11c, the hole 15 is fitted into the bag-like projection 14 while the other side 11b of the two sides is bent inward.
The portion of the bag-like projection 14 protruding from the portion 5 is crimped by a press.

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 box-shaped case by bending each side of a polygonal metal plate inward, and a sheet metal case manufactured by the method.

[0002]

2. Description of the Related Art Conventionally, as a structure of this kind, generally, a plate having a through-hole subjected to burring and a plate having a hole through which it can pass are overlapped with each other, and a projection formed by burring is formed. Was plastically deformed by pressing and compression, and the two plates were joined to form a box. Alternatively, align the hole opened in the plate with the hole in the other plate, insert metal such as rivets into the holes in the two plates, press the rivets from both sides of the superimposed plates, plastically deform by compression, and join Then the case was being manufactured.

Hereinafter, a first method of a conventional case manufacturing method will be described with reference to the drawings. First, as shown in FIG. 4, a square metal plate 1 such as SPCC is prepared.
Bend line 2a on one side 1a of two adjacent sides
The burring protrusion 4 is formed on one side and the hole 5 for fitting to the burring protrusion 4 is formed on the other side at symmetrical positions on both sides of the portion where the notch 3 is formed. After being bent inward at right angles along the fold line 2a, the outer portion 1c of the cut 3 is further bent at right angles inward along the fold line 2c, and then the other side 1b of the two sides is bent inward. FIG.
After the hole 5 is fitted into the burring protrusion 4 as shown in FIG. 5A, the portion of the burring protrusion 4 protruding from the hole 5 is caulked by a punch 6 of a press, and the two are joined as shown in FIG. I do. FIG. 6 shows the joint of the case manufactured in this way.

[0004] As a second method, as shown in FIG.
A hole 7 is provided in place of the burring projection 4, and two sides 1a, 1
There is also a method in which the rivets 8 are inserted into both the holes 5 and 7 after the b is overlapped, and the rivets 8 are caulked with the punch 6 of the press to join the two.

[0005]

However, in the above-mentioned first method, a through hole is formed at the joint portion by a burring projection, and the electric circuit board accommodated in the manufactured case is externally mounted. There is a problem that dust and the like infiltrate into the product, thereby deteriorating the quality of the product. The second
In the method (1), there is a problem that a separate part such as a rivet is required, and the cost is increased.

The present invention has been made to solve the above-mentioned conventional problems, and is intended to manufacture a sheet metal case having no through hole in a manufactured case without largely changing a conventional manufacturing method, that is, without changing manufacturing equipment. It provides a method.

[0007]

According to a method of manufacturing a sheet metal case of the present invention, a cut is made on one of two adjacent sides of a polygonal metal plate, and both sides of the cut portion are formed on both sides. One side is formed with a bag-shaped projection, and the other side is formed with a hole that fits into the bag-shaped projection. Both sides of the cut portion are bent inward, and the other side of the two sides is bent inward. After fitting the bag-shaped protrusion into the hole, the portion of the bag-shaped protrusion protruding from the hole is caulked, and both sides of the cut portion are joined. , Without significantly changing the conventional manufacturing method, that is, without changing the manufacturing equipment,
A sheet metal case having no through hole in the manufactured case can be manufactured.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First, as shown in FIG.
A metal plate 11 having a rectangular shape is prepared, and a cut 13 is formed along one of the adjacent sides 11a of the metal plate 11 along a bending line 12a, and symmetrical positions on both sides of the cut 13 are formed. On one side, a bottomed cylindrical bag-shaped projection 14 is formed by drawing, and on the other side, a hole 15 to be fitted to the bag-shaped projection 14 is formed by punching, and one side 11a is formed at the bending line 12a. 2A, the outer portion 11c of the cut 13 is bent inward at a right angle along the bending line 11c, and then the other side 11b of the two sides is bent inward. After the hole 15 is fitted into the bag-shaped projection 14 as shown in FIG. 2), the portion of the bag-shaped projection 14 protruding from the hole 15 is caulked with a punch 16 of a press, and the two are joined as shown in FIG. I do. FIG. 3 shows a joint portion of the case manufactured in this manner, and other corner portions (not shown) have the same configuration.

In the above embodiment, the bag-shaped projection is formed by drawing of a press, but may be formed by half blanking in the forging field. Also. Although described as a square case, other polygons are equally feasible. The case in the present invention includes a case composed of a lower case and an upper case.

[0010]

As described above, according to the method of manufacturing a sheet metal case of the present invention, a cut is made in one of two adjacent sides of a polygonal metal plate, and a portion of the cut in which the cut is made is formed. On both sides, one side is formed with a bag-like projection, and the other side is formed with a hole that fits into the bag-like projection, and both sides of the cut portion are bent inward, respectively, and the other side of the two sides Is bent inward, the bag-shaped protrusion is fitted into the hole, and then the portion of the bag-shaped protrusion protruding from the hole is caulked to join both sides of the cut portion. Thus, it is possible to manufacture a sheet metal case having no through hole in a manufactured case without largely changing a conventional manufacturing method, that is, without changing manufacturing equipment. Thus, when the case is used as a casing of a control unit or the like, foreign matter such as dust from the outside can be prevented from entering the electric circuit board housed in the case, which greatly improves product quality. Can contribute. Also, since other parts such as rivets are not used, a significant cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a partial plan view illustrating a sheet metal state of a case according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a case joining step in the embodiment of the present invention.

FIG. 3 is a partial perspective view showing a completed state of a case according to the embodiment of the present invention.

FIG. 4 is a partial plan view showing a sheet metal state of a case in a conventional example.

FIG. 5 is a partial sectional view showing a case joining process in a conventional example.

FIG. 6 is a partial perspective view showing a completed state of a case in a conventional example.

FIG. 7 is a partial cross-sectional view showing another joining step of the case in the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Metal plate 11a One side 11b The other side 11c Outer part of cut 12a, 12b, 12c Bending line 13 Cut 14 Bag-shaped protrusion 15 Hole 16 Press punch

Claims (2)

[Claims] 1. A cut is made in one of two adjacent sides of a polygonal metal plate, and a bag-like projection is formed on one side and the bag is formed on the other side on both sides of the cut portion. Forming a hole that fits into the protrusion, bending both sides of the cut portion inward, bending the other of the two sides inward, and fitting the bag-like protrusion into the hole. And then joining both sides of the cut portion by caulking a portion of the bag-like protrusion protruding from the hole. 2. A sheet metal case manufactured by the manufacturing method according to claim 1.