JPH0682912B2 - Method of soldering circuit board and circuit parts - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for soldering a circuit board and a post-installed circuit component, and more particularly, the post-installed circuit component is a part having a contact relationship in which flux must be avoided. It is effective for soldering.

Configuration of conventional example and its problems When trying to solder the circuit components after mounting to the circuit board,
Conventionally, a troublesome process was required.

In the following, as a conventional example, a method of soldering a metal base circuit board and a post-installed circuit component which are often used in a small DC motor will be described for the purpose of effective heat diffusion or shielding effect. FIG. 1 shows a small DC motor mounted with a metal base circuit board, where 1 is a motor frame and 2 is a motor frame.
Is a metal base circuit board that constitutes a control circuit, has single circuit components 3 and 4, is fitted into the motor frame 1, and is crimped together at the joint.

FIG. 2 is an enlarged view of the vicinity of the soldering portion of the brush terminal plate 4 which is a circuit component to be attached later. An insulating layer 6 is formed on the surface of the metal base 5, and conductor lands 7 are formed thereon. The brush terminal plate 4 is joined to the conductor lands 7 by the solder 8.

When the brush terminal plate 4 is to be soldered in the metal base circuit board having such a configuration, for example, as shown in FIG. 3 (a), the solder-plated steel plate 9 is punched and molded into a brush terminal plate shape, The brush terminal plate 4 is brought into contact with the cream solder 10 previously applied to the conductor land 7 to be soldered as shown in FIG. 3 (b), and this is heated by the soldering iron 11. Has adopted a method of soldering both.

However, in the above method, the number of steps for applying the cream solder to the circuit board on which the circuit components are previously soldered by the reflow method or the dip method is increased, which not only increases the cost but also increases the brush terminal plate. For parts with contact relationships such as 4, contact points are adversely affected by solder flux adhesion, vaporization, etc.
It had the drawback of significantly impairing its reliability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above drawbacks of the prior art, and an object of the present invention is to reduce the number of steps while ensuring the reliability of post-soldering.

In order to achieve the above object, the soldering method of the present invention,
The first step of soldering the circuit component by the reflow method or the dip method and forming the solder swell on the conductor land, which is to be soldered in the later second step, is A second step of heating and soldering the formed terminal portion against the conductor land on which the solder pile is formed by pressing with a thermocompression bonding head. When the retrofit component is the brush terminal plate of the DC motor described in the conventional example, the brush terminal plate is a metal plate having a solder plating layer formed on at least a part of the brush terminal plate as a conductor land in at least the second step. The terminal portion to be soldered has the above-mentioned solder plating layer formed on the end face as well, and a metal terminal plate punched by press work is used so that the width thereof spreads in the width direction toward the end face portion of the terminal.

Description of Embodiments Embodiments will be described in detail below with reference to the drawings, taking the same small DC motor as the conventional example as an example.

4 (a), (b), and (c) show an embodiment of the present invention, and the same symbols as in FIG. 2 indicate the same. Now, as shown in FIG. 4 (a), the steel plate 12 partially subjected to the molten solder plating 15 is formed so that the solder plating layer is formed also on the end surface portion of the soldering terminal. It is left as it is, punched out in a shape that spreads in the width direction toward this end face portion, and this is punched into the brush terminal plate
Mold as. In the conventional punching process, the plated layer is not formed on the end face even if the plated steel plate is punched,
Therefore, in order to obtain good solderability, the original plate of the steel sheet was punched out, and then a single product was plated.However, in the punching process of the present invention, the original plate of the steel sheet is passed through the hot-dip galvanized layer in a hoop shape. It is possible to make a line by applying partial molten solder plating 15 and then directly transferring to the transfer press and punching, which is very mass producible.

Next, as shown in FIG. 4 (b), the brush terminal plate 4 is soldered to the conductor land 7 in which the solder heap 13 of the circuit board on which the circuit components are already soldered by solder reflow or solder dip is formed. Touch the part. By applying heat to both of them at the same time as pressure with the head 14 for thermocompression bonding, the solder plating 15 and the solder deposit 13 are melted via the terminal portion 4, and the brush terminal plate 4 of the brush terminal plate 4 is melted as shown in FIG. 4 (c). The brush terminal plate 4 and the conductor lands 7 are joined by sneaking into the upper surface of the terminal board along the wide plating layer 16 and cooling the soldered portion at this point. in this case,
The terminal to be soldered is not limited to the one formed by punching, and a lead plated with solder of a normal circuit component as shown in FIG. 1C can be similarly soldered. Further, the soldering method of the present invention can be applied to not only a metal base circuit board but also a circuit board based on a synthetic resin laminated plate as long as it can withstand solder reflow and solder dip.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to solder post-installed parts, particularly punched terminals such as a brush terminal plate, as they are without being re-applied with cream solder, which is a conventional method. It is possible to reduce man-hours. Further, after the flux cleaning after the first step, by adopting the soldering method of the second step of the present invention,
Since the influence of the flux can be ignored, it is very effective for soldering a single component having a contact relationship.

[Brief description of drawings]

FIG. 1 is a sectional view of a conventional example in which a metal base circuit board is mounted on a small direct current motor, FIG. 2 is an enlarged sectional view of a soldering portion of a brush terminal plate, and FIGS. 3 (a) and 3 (b) are conventional examples. Fig. 4 (a), (b), Fig. 4 (a), (b)
FIG. 3C is a sectional view of a principal part showing a terminal board punching procedure and a soldering procedure thereof according to an embodiment of the present invention. 4 ... Brush terminal plate, 5 ... Metal base, 6 ... Insulating layer,
7 ... Conductor land, 12 ... Partial solder-plated steel plate, 13 ...
Heap solder part, 14 …… Head for thermocompression bonding, 15 …… Melted solder plating layer of terminal board, 16 …… Solder plating part of terminal board.

Front page continuation (72) Inventor Shinji Ueda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-58-32486 (JP, A) JP-A-56-76594 (JP, A) JP 56-94796 (JP, A) JP 54-76975 (JP, A) JP 37-10560 (JP, B1) JP 43-13705 (JP, Y1)

Claims (2)

[Claims] 1. A first step of soldering a circuit component by a reflow method or a dip method and a soldering step on a conductor land, which is to be soldered in a second step afterwards, and a rearward circuit element. And a second step of heating and soldering the terminal portion on which the solder plating layer is formed to the conductor land on which the solder deposit is formed by pressing with a thermocompression bonding head and soldering the circuit board and the circuit component. How to attach. 2. A terminal portion for soldering a metal plate having a solder plating layer formed on at least a part thereof to a conductor land in at least a second step of a circuit part to be retrofitted, wherein the solder plating layer is also formed on an end face. The method for soldering a circuit board and a circuit component according to claim 1, wherein the metal terminal is punched by press work so that the width thereof spreads in the width direction toward the terminal end face portion.