JPH11162538A - Wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the heat capacity of a part to be soldered so as to facilitate temperature raising, improve its solderability and reduce working hours by forming a slit in a soldering terminal part of a molded wiring board. SOLUTION: A terminal slit part 1a is formed longitudinally at the center of a tab terminal 1 of a molded resin part 2 of a wiring board. By virtue of this structure, the heat capacity of the tab terminal 1 for itself is reduced and the heat transfer to a frame joined to the tab terminal 1 is suppressed, so that its solder wettability in soldering is improved and the soldering workability can also be improved. In addition, the solder is filled in the terminal slit part 1a and a crisscross solder fillet is formed, so that the soldering strength can be improved without reducing a conductive part. Still additionally, the rigidity of the tab terminal 1 is reduced by virtue of the terminal slit part 1a, and thereby, the tab terminal 1 can be inserted as if it is lured into a printed circuit board while being deformed in response to the displacement in the insertion into the printed circuit board, so that the insertion workability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-made metal frame which is soldered to an electronic control unit or the like used in general household appliances such as an air conditioner by a dipping soldering device or the like and which is intended to flow an electric current. The present invention relates to an insert-molded wiring board (hereinafter, referred to as a molded wiring board).

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 9, a metal frame portion is bent at a right angle and a tip portion is processed into a plate shape or a tab terminal shape as shown in FIG.
It was inserted into the printed circuit board and soldered.

[0003]

However, in the above-mentioned conventional configuration, when a metal frame for forming a circuit as an electronic control device is insert-molded with a resin, mutual stress due to the difference in expansion and contraction caused by heat of the metal frame and the resin. May cause cracks or deformation of the molding resin, and also stress may be applied to the solder joints between the printed circuit board and the frame, causing defects such as solder cracks. When the length was long, the stress increased and it was easy to occur.

In addition, when a large current is applied, the temperature rise of self-heating due to energization is added, and the heat cycle width is increased, so that it is more important to secure the solder reliability especially at the soldered portion.

Further, when a large current is applied, the metal frame serving as the conductive portion becomes large, including the plate pressure, and thus has a large heat capacity. Therefore, the heat of the solder is absorbed by the frame at the time of soldering, and Does not rise sufficiently, so that the solder fret or the like becomes low, or the wetting property of the solder deteriorates. Therefore, the soldering time is prolonged, the workability is poor, and the resin around the frame due to long-time heating may be melted or deformed by heat.

On the other hand, the end of the terminal of the metal frame is likely to be an edge of a burr or the like formed by press molding, and if the wire drawn around the terminal touches the edge, the wire may be damaged or poor insulation. You can install separate parts,
Restrictions were placed on the routing position, and this was likely to hinder miniaturization and workability.

The present invention solves such a conventional problem. In a molded wiring board to be soldered to a printed wiring board, a terminal having good solderability is provided, and an electric wire is provided at a terminal end. It is an object of the present invention to improve reliability and operability by avoiding easy contact.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a soldering portion of a metal frame of a molded wiring board, in which heat at the time of soldering is transmitted to the frame and reduced, and soldering is performed. By reducing the heat capacity of the terminal portion, the temperature can be easily raised, and the solderability is improved and the working time is shortened.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is such that a vertical slit is provided at the center of a terminal portion of a molded wiring board to be soldered. According to this configuration, the heat capacity of the terminal itself and the heat transfer to the frame connected to the terminal are suppressed,
In addition to improving the solder wetting property during soldering and improving solder workability, the solder turns around the slit part, the solder fret is formed in a cross shape, and the soldering strength is improved without reducing the conductive part Can be achieved. Further, the rigidity of the terminal portion is further reduced by the slit, and the terminal can be inserted so as to be guided while being deformed with respect to a positional deviation at the time of insertion into the printed circuit board, thereby improving the insertion workability.

According to a second aspect of the present invention, a circular punched portion is provided at the center of the terminal portion in the terminal portion of the molded wiring board to be soldered. According to this configuration, the heat capacity of the frame can be reduced and the heat transfer can be suppressed at the circular punched hole portion, as described above, and the solder workability and reliability can be improved.

According to a third aspect of the present invention, a semicircular cut-and-raised portion is provided at the right-angled bent portion at the base of the terminal portion. According to this configuration, similarly to the above, the heat capacity of the frame can be reduced and the heat transfer can be suppressed, and the cut-and-raised portion can be fixed with resin. And the positional accuracy, such as the fixing strength and verticality, can be improved.

According to a fourth aspect of the present invention, an S-shaped thin bent portion is provided at the base of the terminal portion. According to this configuration, in addition to suppressing the frame heat transfer in the same manner as described above, the S-shaped portion absorbs and relaxes the stress caused by the expansion and contraction due to the difference in the coefficient of thermal expansion between the metal frame and the resin. Cracks and warpage of the mold resin can be suppressed.

According to a fifth aspect of the present invention, the base of the terminal portion is provided with an encircling rib by molding resin. According to this configuration, the wire drawn around the terminal can be isolated from the edge of the terminal burr or the like generated when the terminal is punched by the die, and damage to the wire can be prevented.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) In FIG. 1, a terminal of a molded wiring board to be inserted and soldered into a hole provided in a printed circuit board has a slit 1a vertically formed in a central portion thereof, and a metal frame is formed by pressing a metal frame. Show things. FIG. 4 shows a combination of the molded wiring board and the printed circuit board. The terminals 1 from the molded wiring board are inserted into holes provided in the printed circuit board 4, soldered, and connected.
The terminal part is divided into two by the slit provided in this terminal, the heat capacity of the terminal itself and the heat transfer to the frame connected to the terminal are suppressed, the solder wetting property at the time of soldering is improved, and the soldering work is facilitated. Can be.

Also, as shown in FIGS. 2 and 3, the slits in the terminal portions are formed to extend above the shoulder portions of the terminals corresponding to the upper surface of the printed circuit board. Then, the soldering is made into a sandwich shape by the printed board and further made into a cross shape at the slit portion. Therefore, by increasing the soldering strength, it is possible to secure the strength against the stress due to the heat cycle caused by the difference in thermal expansion between the metal frame and the molding resin, and to suppress the occurrence of solder cracks and the like.

Furthermore, the conductor, which is a conductor, wraps around the slit portion, and the conductive portion does not decrease because the slit portion is buried, so that the resistance of the connection portion increases.
The accompanying temperature rise can be prevented.

Further, the terminal portion is provided with a chamfered portion for guiding, and the division by the slit reduces rigidity and facilitates deformation. Therefore, even when a slight displacement occurs when inserting the printed circuit board, the rigidity is reduced and the insertion becomes easy. When a number of terminals from the molded wiring board are inserted at the same time, dimensional variations between the terminals are absorbed, thereby improving the insertability.

(Embodiment 2) FIG. 5 shows a terminal part to be soldered of a molded wiring board, in which a circular punched portion is provided at the center of the terminal part. Like the above, it is formed by simultaneous processing at the time of processing the terminal portion. The hole 6 is provided at a position where a part thereof can be seen when inserted and mounted on the solder printed circuit board 4, and the terminal soldering portion can be easily separated by this hole. Further, when the solder is mounted on the printed circuit board and soldered, the solder wraps around the circular hole, and the strong soldering can be performed as described above.

According to this embodiment, the heat capacity of the frame can be reduced and the heat transfer can be suppressed at the circular punched hole portion as described above, and the workability and reliability of the solder can be improved. it can.

(Embodiment 3) FIG. 6 shows a semi-circular cut-and-raised portion 7 provided at a right-angled bent portion at the base of the terminal portion.
The terminal portion is formed by bending the frame at a right angle. A semicircular cutout is made in a portion serving as a bending starting point, and only a portion to be soldered is bent at a right angle to the frame. Therefore, the semicircular portion is formed so as to protrude on an extension line on the same plane as the frame.

According to this embodiment, the heat transfer to the frame is suppressed by the semicircular holes formed in the frame in the same manner as described above, and the solderability can be improved.

Further, since the semicircular cut-and-raised portion is fixed by the resin, the terminal can be held in a well-balanced manner from both the terminal fixing area and the terminal bending. Can be easily fixed, and the positional accuracy such as the fixing strength and the verticality of the terminal can be improved.

(Embodiment 4) FIG. 7 shows an S-shaped thin bent portion provided at the base of the terminal portion with a soldered portion and a right-angled bent portion from a frame. According to this embodiment, similarly to the above, the distance between the terminal and the resin portion is increased in the S-shaped portion, and the heat transfer to the frame is suppressed by making the terminal thinner. On the other hand, the S-shaped portion can be used not only in the vertical direction but also in the vertical direction of the frame due to the expansion and contraction stress caused by the difference in the coefficient of thermal expansion between the metal frame, the molding resin and the printed circuit board. In addition, absorption and relaxation in the width direction can be suppressed, and cracks in soldering, cracks in the mold resin, and warpage can be suppressed.

(Embodiment 5) FIG. 8 shows a case in which the base of the terminal portion is provided with an encircling rib by molding resin.

According to this embodiment, if the wire drawn around the terminal touches the edge of the terminal burrs or the like generated when the terminal is punched by the die, the wire coating is damaged and the insulation breakdown is caused. By providing an encircling rib with a molding resin at the base of the terminal, the electric wire does not easily come into contact with the terminal, and the wiring can be easily routed. Further, it also reinforces the external force applied to the terminal portion.

[0027]

As is apparent from the above embodiment, the first aspect of the present invention has a slit provided in the soldering terminal portion of the molded wiring board. Heat transfer to the frame and the temperature rise is difficult,
By reducing the heat capacity of the part to be soldered,
The temperature can be easily increased, the solderability can be improved and the working time can be shortened, and excellent effects are obtained in terms of solder strength and workability of inserting components.

The second aspect of the present invention has an excellent effect in terms of solderability by reducing the heat capacity as described above.

According to the third aspect of the present invention, in addition to the improvement of the solderability due to the reduction of the heat capacity as described above, according to this structure, the terminal position accuracy can be easily ensured.

According to the fourth aspect of the present invention, in addition to the improvement of the solderability by reducing the heat capacity as described above, according to this structure, the stress caused by the difference in the coefficient of thermal expansion between the resin and the metal frame is absorbed and relaxed. This has the effect of suppressing the occurrence of cracks in the terminal soldering portion and the mold resin, and ensuring reliability.

According to a fifth aspect of the present invention, the periphery of the terminal is surrounded by a resin so that the electric wire routed in the vicinity of the terminal does not touch the terminal. It has the effect of protecting.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a slit of a soldered terminal portion of a molded wiring board according to one embodiment of the present invention.

FIG. 2 is a sectional view showing a soldered state of the embodiment.

FIG. 3 is a side sectional view showing a soldered state of the embodiment.

FIG. 4 is a schematic configuration diagram showing bonding between a molded wiring board and a printed circuit board according to an embodiment of the present invention.

FIG. 5 is a sectional view of a terminal portion according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a terminal part according to a third embodiment of the present invention.

FIG. 7 is a sectional view of a terminal portion according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view of a terminal portion according to a fifth embodiment of the present invention.

FIG. 9 is an exploded perspective view showing a terminal structure of a molded wiring board showing the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solder terminal part of molded wiring board frame 1a Terminal slit part 2 Resin molding part 3 Solder 4 Printed circuit board 4a Printed circuit board insertion hole part 5 Mold wiring board 6 Terminal part circular hole part 7 Terminal root part cut-and-raised part 8 S-shaped bent portion at terminal root 9 Resin molded rib at terminal root

Claims (5)

[Claims] 1. A wiring board, which is solder-connected to an electronic control unit or the like and insert-molded with a resin by inserting a metal frame for the purpose of flowing an electric current, has a vertical slit at the center of a terminal portion of the metal frame to be soldered. A wiring board having: 2. A circular punched portion at the center of a terminal portion of a metal frame to be soldered in a wiring board which is solder-connected to an electronic control device or the like and is insert-molded with a metal frame resin for the purpose of flowing an electric current. A wiring board having: 3. The wiring board according to claim 1, wherein a semicircular through-hole is provided at the terminal bent portion of the metal frame. 4. The wiring board according to claim 1, further comprising an S-shaped thin bent portion at the base of the terminal portion of the metal frame. 5. The wiring board according to claim 1, further comprising a rib surrounded by a resin at the base of the terminal of the metal frame.