The priority application Number Japan Patent Application No. 2007-111024 upon which this patent application is based is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a joining method which joins a pair of metal plates, and a joined unit having a pair of metal plates joined each other.
2. Description of the Related Art
Generally, various electronic devices, for example a light such as headlights and a rear light, and a motor such as a starter motor and a motor for air condition, are mounted in a vehicle as a mobile object.
A wiring harness and an electronic connection box are arranged in the vehicle so as to provide electrical power into the above mentioned various electronic devices. The wiring harness, of course, includes multiple electrical wires and a connector. The connector has a terminal made of conductive plate and a connector housing made of an insulation synthetic resin. The connector housing receives the terminal. The connector is connected to various electronic devices.
The electronic connection box has a box body made of an insulation synthetic resin and a wiring board received in the box body. Various electrical parts, for example a relay and a fuse, and a connector of wiring harness are mounted on the box body.
The wiring board has a plurality of conductive bus bars (correspond to metal plates), and an insulating plate which insulates each bus bars electrically. The bus bar is made by punching and bending in a conductive plate. The insulating plate is made of insulation synthetic resin, and is formed into a plane shape.
The wiring board, that is the electronic connection box, electrically connects the various electrical parts such as a relay and a fuse and the electrical wire of wiring harness with a predetermined pattern. Thereafter, the electronic connection box divides electric power provided from a power source in various electronic devices.
The above mentioned bus bars are made by punching and bending in a thick plate. When the bus bars are connected each other, heretofore various welding methods are used. However, when the bus bars are connected each other by welding, a solder used in this welding is formed to a projecting shape. As a result, it is hard to set the bus bars in an insulating plate when the bus bars are assembled in a wiring board. In this case, the bus bars can not be positioned in the insulating plate. Thereby, it is difficult to connect electrically the above electrical parts and the above electrical wire of the wiring harness with a predetermined pattern.
On the other hand, the bus bars can be connected by caulking. In this case, it is difficult to connect electrically fully each bus bar so that a gap is formed to a connection part of the bus bars. Furthermore, after long time advances, the bus bars corrode from the above mentioned gap by moisture in the air. Thereby, electronic resistance between the bus bars increases.
Therefore, an object of the present invention is to provide a joining method of metal plates, which can connect two metal plates without a projection in a surface of the metal plates and a gap, and a joined unit having metal plates which can be connected without a projection in a surface of the metal plates and a gap.
According to a first aspect of the present invention, a joining method of a pair of metal plates includes the steps of: providing one of the pair of the metal plates (herein after, one metal plate) with a hole, providing another of the pair of the metal plates (herein after, the other metal plate) with a projection having a height less than a thickness of the one metal plate, letting the projection pass through the hole, placing the one metal plate on the other metal plate, and crushing a central part of an end surface of the projection. Thereby, the metal plates are joined to each other.
According to a second aspect of the present invention, as mentioned above, the crushing is carried out on a condition that a tapered protrusion 12 is pressed onto the central part of the end surface 5a of the projection 5.
According to a third aspect of the present invention, a joined unit has a pair of metal plates which are joined each other. The one metal plate includes a hole, and the other metal plate includes a projection. The height of the projection is less than a thickness of one metal plate. The projection is let pass through the hole, and the one metal plate is placed on the other metal plate. Thereafter, a central part of an end surface of the projection is crushed in the hole, and an outer peripheral surface of the projection adheres to an inner peripheral surface of the hole.
According to the invention, the projection provided on the other metal plate is inserted into a hole provided in the one metal plate. Thereby, the central part of the end surface of the projection is crushed. A height of the projection is formed smaller than a thickness of the one metal plate. Therefore, the projection in which the central part of the end surface is crushed becomes deformed to an expanded shape in the hole. Thereby, the outer peripheral surface of the projection adheres to the inner peripheral surface. Also, a projection is not produced in a surface of the metal plates so that the projection provided on the other metal plate is enlarged in the hole.
Therefore, the metal plates can be connected without the projection of the surface of the metal plate. Consequently, when the metal plates are used as a bus bar of wiring board of electronic connection box, the metal plates can be located certainly at an insulating plate. Furthermore, it is possible to provide a joined unit which can connect electrical parts mounted on the electronic connection box and electrical wire of wiring harness with a predetermined pattern.
In addition, the joined unit can be prevented from a corrosion of the connection part of the metal plates so that a gap is not produced. Thereby, the electronic resistance between the bus bars does not increase as long time advances.
According to the invention, a tapered protrusion is pressed to the central part of the end surface of the projection. Thereafter, the central part of the projection of the other metal plate is crushed by the tapered protrusion. Thereby, the outer peripheral surface of the projection adheres certainly to the inner peripheral surface of the hole so that the projection is spread.
The above and other objects and features of this invention will become more apparent from the following description taken in conjunction with the accompanying drawings.
A joining method and a joined unit according to one embodiment of the present invention are explained by referring to in
As shown in
The metal plate 2 shown in
The other metal plate 3 shown in
As shown in
The above mentioned joined unit is produced by joining the metal plates 2 and 3. The metal plates 2 and 3 are joined by a pair of dies 10 and 11 which can approach or depart from each other (shown in
When the above mentioned metal plates 2 and 3 are joined, as shown in
According to embodiments, the central part of the end surface 5a of the projection 5 is crushed by inserting the projection 5 formed on the other metal plate 3 into the hole 4 provided in the metal plate 2. In addition, the height of the projection 5 is formed less than the thickness T of the metal plate 2. Thereby, the projection 5 in which the central part of end surface 5a was crushed is expanded in the hole 4, and the outer peripheral surface of the projection 5 adheres to the inner peripheral surface of the hole 4. Furthermore, the projection 5 does not project from a surface of metal plates 2 so that the projection 5 enlarges in the hole 4.
Now therefore, surfaces of metal plates 2 and 3 can maintain a flat, and the metal plates 2 and 3 can be connected without a gap. Also, when the metal plates are used as a bus bar of a wiring board of an electronic connection box, the metal plates can be located certainly at an insulating plate. Furthermore, it is possible to make the joined unit which can steadily connect electrical parts mounted on the electronic connection box and electrical wires of wiring harness with a predetermined pattern.
Additionally, in the joined unit, since a gap is not produced between the metal plates 2 and 3, a corrosion which is caused to a connection part of the metal plates 2 and 3 can be prevented. Also, electronic resistance between the metal plates 2 and 3 does not increase as long time advances.
Moreover, since the tapered protrusion 12 is pressed to the central part of the end surface 5a of the projection 5, the central part of the end surface 5a of the projection 5 is crushed by the protrusion 12. Thereby, the projection 5 is pushed and expanded in the hole 4 by an outer peripheral surface of the protrusion 12. Accordingly, the outer peripheral surface of the projection 5 and the inner peripheral surface of the hole 4 adhere closely.
The inventors actually manufactured the above mentioned joined unit 1. The metal plate 2 of the joined unit 1 is made of copper alloy, and a thickness T of the metal plate 2 is 0.64 mm. On the other hand, the other metal plate 3 of the joined unit 1 is made of pure copper, and the thickness T of metal plate 3 is 0.64 mm. Those metal plates 2 and 3 are joined.
The metal plates 2 and 3 are made of single metal in which an outer peripheral surface is not plated in the above mentioned embodiments. However, in the present invention, it is appreciated that coating the outer peripheral surface of the metal plates 2 and 3 are adapted.
The embodiments of the present invention are only exemplary and not limited thereto. Any modification and alteration are within the scope of the present invention.
Number | Date | Country | Kind |
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2007-111024 | Apr 2007 | JP | national |