JP5052394B2 - Electronic component mounting method - Google Patents

Description

  The present invention relates to an electronic component mounting method, and more particularly to a technique that can be suitably applied in caulking connection in mounting an electronic component having a cylindrical lead terminal and a metal substrate.

  Various mounting structures are used to mount electronic components. Also, there are various types of electronic components, and the terminal shapes are also various. Among electronic components, electronic components with lead terminals are also known. As a method for mounting an electronic component with a lead terminal on a mounting substrate, for example, a mounting method as in Patent Document 1 is known.

According to the mounting method according to Patent Document 1, after inserting the lead terminal into the hole of the substrate, the lead terminal is pressed from two opposite directions to cause a part of the lead terminal to be plastically deformed to generate a flash. Electronic components are fixed to the substrate by protrusions caused by burrs.
Japanese Patent Publication No. 6-85480

  The electronic component mounting method described above is effective when electronic components are mounted in holes provided in the substrate, but is difficult to apply as it is when directly connected to a metal substrate without using solder. As an environmental measure, a desired lead-free solder that does not contain a lead component has also been developed. However, it is preferable from an environmental measure that mounting is possible without using solder. Therefore, the present inventors have studied to connect using a partial plastic deformation technique of the lead terminal by pressing.

An electronic component mounting method examined by the present inventors is shown in FIG. The electronic component is a light-emitting diode 1 called a so-called bullet type, and a pair of lead terminals 2 and 2 are formed in opposite directions as shown in FIG.
First, as shown in FIG. 1A, a flat metal substrate 3 having a protruding portion 3a was prepared, and the protruding portion 3a was bent and raised as shown in the right figure of FIG. Next, the lead terminal 2 of the light emitting diode 1 is placed on the metal substrate 3. At this time, as shown in the left side view of FIG. 1B, the lead terminal 2 is brought into contact with the protruding portion 3a and the bottom portion 3b, and the protruding portion 3a is further bent and temporarily fixed in this state (right side of FIG. 1B). Figure). Thereafter, as shown in FIG. 1C, the temporary fixing portion 4 was welded by a welding machine 5, thereby fixing the electronic component 1 and the metal substrate 3 electrically and mechanically.

  Although it was possible to fix an electronic component without using solder by the said examination, there existed the following problems. That is, since the lead terminal has a cylindrical shape, the electronic component 1 rotates in the direction D shown in FIG. 3 when temporarily fixed. For this reason, it is necessary to confirm the attachment position when performing welding, which causes a serious problem as an optical element in which the irradiation direction of the light emitting diode 1 deviates from a predetermined position if welding is performed while rotating. In addition, there is a problem that only temporary fixing requires welding because the connection between the two companies is insufficient as described above, and the equipment cost is high because a welding machine is required. These are common problems of this type of light emitting diode with lead terminals.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a simple attachment method capable of reliably performing electrical connection and mechanical connection in a simple process. .

In order to achieve the above object, the present invention has the following means.
That is, the invention described in claim 1 includes a step of applying pressure to a connecting portion extending along an attachment axis of a lead terminal of an electronic component and pressing to form a substantially elliptical section or a rectangular section, and bending the metal substrate. A step of temporarily fixing the connecting portion by sandwiching the connecting portion, and a step of caulking and fixing by applying pressure from the outside after the temporary fixing, wherein the temporary fixing step is a direction orthogonal to the mounting axis. Are bent so as to have a bottom surface and a top surface parallel to the major axis of a substantially elliptical shape or a rectangular shape, and are sandwiched between the bottom surface and the top surface to be temporarily fixed. The caulking step is performed from the bottom surface and the top surface of the metal substrate. The above-mentioned object is to provide an electronic component mounting method characterized by applying pressure to a caulking type whose installation area is small on the upper surface side It is intended to achieve that.

  Using electronic parts with lead terminals that have undergone a pressing process that plastically deforms into an elliptical cross section, by connecting by caulking, it is possible to perform mounting that prevents rotation of the electronic parts, and to solve the above problems It is possible to provide a method for attaching components.

  Further, it is possible to provide a connection having higher durability against vibration compared to welding. By providing an attachment method in which the connection state is a line connection, it becomes a highly reliable connection structure in which tearing against vibration hardly occurs, and an electronic component connection structure with improved durability can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same structure as the structure demonstrated by the background art mentioned above, and a part of the description is abbreviate | omitted.

  FIG. 4 explains the electronic component mounting method according to the first embodiment of the present invention in order. The electronic component 1 will be described using an example in which a light emitting diode having the formed lead terminal 2 shown in FIG. 2 is used. The lead terminal has a cylindrical cross section and has a pair of lead terminals 2 and 2 ′ of a positive electrode and a negative electrode. Each terminal is bent in the middle and extends in the opposite direction and is arranged in a straight line. This shaft, that is, the mounting shaft is X. 2A is a side view and FIG. 2B is a top view.

  First, as shown in FIG. 4A, a flat metal substrate 3 having a protruding portion 3a is prepared, and the protruding portion 3a is bent as shown in the right figure of FIG. In parallel with this operation, as shown in FIG. 4B, the connecting portions 2a and 2a 'of the lead terminals 2 and 2' are crushed and plastically deformed into an approximately elliptical cross section. For the crushing operation, for example, the connecting portions 2a and 2a 'are placed on the lower flat table 11 in a predetermined direction, and pressure is applied from above by the pressure head 12 by hydraulic pressure or the like. To do. At this time, the plane table 11 and the surface connected to the lead terminal of the pressure head 12 are parallel planes. By using parallel planes, the bottom surface and the top surface of the metal substrate, which will be described later, can be kept substantially parallel when plastically deformed into an approximately elliptical shape, and the mounting direction can always be maintained in a constant direction. Note that it is preferable that the metal substrate 3 be made of iron or a plate provided with an anti-oxidation coating on the surface of the iron plate because the cost can be reduced.

  Next, as shown in FIG. 4 (c), the connecting portions 2a and 2a ′ of the lead terminal 2 subjected to the pressing process of FIG. 4 (b) are brought into contact with the metal substrate 3, specifically, the protruding portion 3a and the bottom 3b. Then, the protruding portion 3a is further bent and temporarily fixed in the contacted state. At this time, the ellipse major axis of the connection portion 2 a having a substantially elliptical cross section is substantially parallel to the bottom surface 31 and the top surface 32 of the metal substrate 3, and the connection portion 2 a is positioned in the space between the bottom surface 31 and the top surface 32. By narrowing the gap between the bottom surface 31 and the top surface 32 and sandwiching the short axis of the connection portion 2a, the connection portion 2a, that is, the electronic component 1 can be prevented from rotating. In addition, although the cross-sectional shape of the connection parts 2a and 2a 'plastically deformed is an ellipse, the cross-sectional shape may be a substantially rectangular shape.

  Thereafter, as shown in FIG. 4 (d), the caulking device 6 performs this caulking. As shown in FIG. 4E, the lead terminal 2 of the electronic component 1 includes connection portions 2a and 2a 'extending in the opposite direction from the electronic component 1, and these are located on the attachment axis X. The connecting portions 2a and 2a 'are set on the mounting tables 6c and 6d of the crimping device 6 so that the elliptical long axis of the connecting portions 2a and 2a' is parallel to the mounting tables 6c and 6d. Thereafter, pressure is applied by the caulking die 6b on the arrow and the right side is caulked, and then the right side is caulked by the caulking die 6a on the arrow. By independently performing the caulking operation on the left side and the caulking operation on the right side, even when the lead terminal is elongated by the caulking process, the metal substrate 3 and the lead terminal can be connected without applying unnecessary stress. . The arrow shape is a shape in which the tip has a triangular prism shape. When comparing the installation area of the flat table and the metal plate with the installation area of the pressure head and the metal plate, the pressure head and the metal plate And a pressure head having a shape that does not cause point contact. Further, the caulking work may be performed in the order of the left side and the right side.

When the crimping process is finished, the electronic component 1 is electrically and mechanically connected and fixed by crimping each of the lead terminals 2 formed as shown in FIG.
Table 1 shows the experimental results when caulking and fixing are performed under the same conditions except that a conventional cylindrical lead terminal having a circular cross section is used and an elliptic column shaped lead terminal having an elliptical cross section is used.

In the experiment, a bullet-shaped LED was used as the electronic component 1, a lead terminal 2 formed in a direction orthogonal to the mounting axis X and the emission direction from the bullet-shaped LED was used, and the metal substrate 3 had a thickness of 0.5 mm. An iron substrate was used. In addition, ultrasonic welding was continuously performed as an evaluation method, and evaluation was performed based on the number of times ultrasonic vibration was applied from the lighting state to the non-lighting state by applying ultrasonic vibration.
As can be seen from Table 1, in the case of using the cylindrical lead terminal in the case of the above-described examination, lighting was not generated when the predetermined ultrasonic vibration was applied 14 times, but the elliptical columnar lead according to the embodiment of the present application was used. In the case of the terminal, even when the ultrasonic vibration of the same condition was lit 20 times or more, stable lighting was possible without causing unlighting. The ultrasonic welding performed as a vibration test was evaluated using a SONOPET-2100B ultrasonic welding machine.

  From this, it is understood that the connection stability is improved by using the elliptical lead terminal. In addition, since the lead terminal 2 of the electronic component 1 has a connecting portion 2a, 2a ′ that is formed and parallel to the X axis, the experiment in which the ultrasonic vibration is continuously applied has shown that X times in the conventional example is 14 times. Although the electronic component 1 rotates around the axis, in the present invention, it did not rotate even after ultrasonic vibration was continuously applied 20 times or more.

  As described above, according to the present invention, electrical connection and mechanical connection can be reliably performed with a simple process. In addition, a highly reliable connection structure can be provided.

  The electronic component mounting method is not limited to the above-described embodiment. For example, a metal substrate using a copper material is used, or the entire metal substrate is bent instead of a metal substrate having a protruding portion. Of course, various changes can be made without departing from the gist of the present invention, such as interposing a lead terminal between them.

It is a figure explaining the examination example of the attachment method of an electronic component in order of a process. It is the top view and top view which show an example of the electronic component with a lead terminal. It is a top view which shows the connection state of the electronic component with a lead terminal, and a metal plate. It is a figure explaining the attachment process of the electronic component of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting diode 2 Lead terminal 2a Connection part 3 Metal substrate 3a Protrusion part 3b Bottom part 4 Temporary fixing part 5 Welding apparatus 6 Caulking apparatus 6a Arrow type 6c, 6d Mounting base

Claims (1)

Applying pressure to the connecting part that extends along the mounting axis of the lead terminal of the electronic component and pressing to form a substantially elliptical or rectangular cross section, and temporarily fixing the metal part by bending the metal part And a caulking process for fixing by caulking by applying pressure from the outside after temporary fixing,
In the temporary fixing step, the metal substrate is bent from a direction orthogonal to the attachment axis so as to have a bottom surface and a top surface parallel to the major axis of a substantially elliptical shape or a rectangular shape, and is temporarily fixed by being sandwiched between the bottom surface and the top surface. Do,
The electronic component mounting method according to claim 1, wherein the caulking step is performed by applying pressure with a caulking die having a small installation area with respect to the metal substrate from the bottom surface and the upper surface of the metal substrate.

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