JPH0642393Y2 - Shield case for high-frequency equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a shield case for high-frequency equipment such as a tuner of a cable television.

[Prior Art] Generally, a circuit configuring a high-frequency device of this type is composed of a plurality of circuit blocks, and each circuit block is shielded from each other by a shield plate in order to prevent mutual electromagnetic interference. ing.

As an example of this kind of high-frequency equipment, the structure of a tuner of a cable television is shown in FIGS. 7 and 8.

As shown in FIG. 7, the tuner 1 has a frame-shaped shield case 4 composed of two case members 2 and 3 having the same width. One case member 2 constituting this shield case 4 is bent at the same position from both ends at the same angle to the same surface side, and the case member 3 between the both ends is another.
Combined by The inside of the shield case 4 includes the case members 2 and 3 and the shield plate 5 or the shield plate 5.
They collide with each other and are divided into a plurality of small chambers 6. A circuit block 7 is fixed in each small chamber 6 as shown in FIG.

In consideration of the manufacturing efficiency of the tuner 1, these circuit blocks 7 are arranged such that adjacent circuit blocks 7, 7 are mounted on a printed circuit board 9 which is connected to each other at a connecting portion 8 to provide necessary electronic components.
It is constructed integrally by mounting 11 (see FIG. 11). When fixing the shield case 4 of the circuit block 7 in the small chamber 6, the connecting portions 8 of the adjacent circuit blocks 7 and 7 are fitted into the cutout portions 12 provided in the shield plate 5, and The shield plate 5 is fitted in the slit 13 between the adjacent circuit blocks 7, 7 of the printed circuit board 9. The position of the printed circuit board 9 in the shield case 4 is defined by the depth of the notch 12 formed in the shield plate 5 and the push-out portion 14 formed in the shield case 4.

As shown in FIG. 9, the shield plate 5 has a tongue piece 5a protruding along the abutting surface of the case member 2, 3 or another shield plate 5, and as shown by an arrow A ₁ , The tongue piece 5a has a printed circuit board 9 on which the electronic component 11 is inserted in advance.
Is inserted into the slit 13 and is bent over the land 9a of the printed circuit board 9 as shown by an arrow A ₂ in FIG.

Then, as shown in FIG. 11, the shield case 4 is soaked and pulled up so that the land 9a (see FIG. 9) side of the printed circuit board 9 faces the molten solder 21 and is almost immersed in the molten solder 21. . As a result, the terminals of each electronic component 11 are soldered to the circuit pattern (not shown) of the printed board 9 and the tongues 5a are soldered to the lands 9a.

[Problems to be Solved by the Invention] By the way, in recent years, the shield case 4 of the tuner 1 of the cable television having the above-described structure is made of a material such as a tin (Sn) -plated material on the surface of an iron plate for cost reduction. Solder plated steel sheet is used. But,
When the shield case 4 is manufactured, the steel base of the plated steel plate is exposed on the cut end faces of the case members 2 and 3 and the shield plate 5 by punching the plated steel plate. Then, due to the rust generated on the cut end face, for example, an electrical connection failure occurs between the shield case 4 and a cover (not shown) that covers the upper and lower openings of the shield case 4, resulting in the characteristics of the tuner 1. Deterioration occurs. Therefore, in order not to generate on the cut end face, the shield case 4 may be melted with solder to a certain depth from the upper and lower open ends of the shield case 4 before soldering the printed circuit board 9 thereto, for example. It is dipped in and pulled up, and solder is attached to the cut end face in advance.

However, in the above-mentioned conventional shield case 4, since the tongue piece 5a of the shield plate 5 projects along the abutting surface of the case members 2, 3 or another shield plate 5, as shown in FIG. , This tongue piece 5a and case members 2, 3
Alternatively, a gap is created between the shield plate 5 and another shield plate 5. Therefore, as described above, the shield case 4 is melted with the molten solder 21.
When it is dipped in and pulled up, as shown in FIG. 12, the molten solder rises in the gap due to its surface tension, and the tongue piece 5a is soldered to the case members 2 and 3 or another shield plate 5b. Will end up. In this way, the tongue piece 5a is the case member.
When soldered to 2, 3 or other shield plate 5,
There is a problem that the slit 13 of the printed circuit board 9 cannot be inserted into the tongue piece 5a to be bent.

In order to solve such a problem, the tongue piece 5a of the shield plate 5 is inserted into the slit 13 of the printed board 9 before the solder is attached to the cut end surfaces of the case members 2 and 3 of the shield case 4 and the shield plate 5. Then, the shield case 4 is dipped in the molten solder from the lower opening end side thereof, and then the case 4 is dipped in the molten solder from the upper opening end side thereof to form a cut end. It is also possible to attach solder.

In this way, the tongue piece 5a is not soldered to the case members 2 and 3 or the shield plate 5 before the tongue piece 5a is bent. However, since the shield case 4 is immersed in the molten solder 21 from above and below, heat is applied to the electronic component 11 mounted on the printed circuit board 9 twice in total, and the characteristics of the tuner 1 are reduced. There is a problem of deterioration.

An object of the present invention is to attach a tongue provided on a shield plate for fixing a printed circuit board to a case member or another shield plate by soldering in a step of attaching solder to the cut end faces of the case member and the shield plate. It is an object of the present invention to provide a shield case for a high-frequency device that prevents the above.

[Means for Solving the Problems] Therefore, the present invention comprises a metal case member punched from a metal plate and a shield plate, and the case member and the shield plate or shield plates are abutted against each other to form an internal structure. Is divided into a plurality of small chambers for accommodating the circuit blocks of the high-frequency circuit formed on the printed circuit board by the shield plate, and the abutting end of the shield plate has a butting surface with the case member or another shielding plate. Shield case for high-frequency equipment including a case having a tongue protruding along a line, the tongue being inserted into a slit formed in a printed circuit board and bent, and being soldered to a land of the printed circuit board. That is, when the case is immersed in the molten solder and pulled up from the side opposite to the protruding side of the tongue, Solder having a width large enough to prevent the gap existing between the shield plate and the case member or the contact surface of the shield plate against which the shield plate is abutted by a force from rising to the tongue side. It is characterized in that a rising prevention portion is provided in the vicinity of the base portion of the tongue piece.

[Operation] By immersing the case in the molten solder, the molten solder tries to rise in the gap toward the tip of the tongue piece due to the surface tension of the molten solder. However, when the molten solder reaches the solder rise prevention portion, the width of the solder rise prevention portion is larger than that of the other portions, so that the molten solder cannot reach the tongue side beyond the solder rise prevention portion.

[Effect of the Invention] According to the present invention, when the molten solder is attached to the case member of the case and the cut end surface of the ground plate, the molten solder does not reach the tongue side beyond the solder rise prevention portion.
Even if solder is attached to the cut end surfaces of the case member and the ground plate before mounting the printed circuit board on the case, the tongue piece of the ground plate is not soldered to the case member and the ground plate, and Since only heat is applied to the electronic components mounted on the printed circuit board when the terminals are soldered to the pattern of the printed circuit board, deterioration of the characteristics of the high frequency device can be prevented.

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

An embodiment in which the present invention is applied to the tuner 1 described in FIGS. 7 and 8 is shown in FIG.

The tuner 1'of FIG. 1 has a tongue piece 5a of the shield plate 5 protruding from the abutting end of the shield plate 5 along the abutting surface of the case members 2, 3 of the shield case 4 or another shield plate 5. A notch 31 is provided as a solder rise preventing portion in the vicinity of the base portion of the.

FIG. 2 shows details of the vicinity of the solder rise prevention portion of one tongue piece 5a.

As shown in FIG. 3, the notch 31 is provided with the shield plate 5 and the case members 3, 4 with which the shield plate 5 is abutted.
Alternatively, the width of the gap between the abutting surface with another shield plate 5 is made larger in the vicinity of the base portion of the tongue piece 5a than in other portions.

In this way, if the notch 31 is provided in the vicinity of the base of the tongue piece 5a of the shield plate 5, the case members 2 and 3 are formed by immersing the solder in the molten solder 21 before mounting the printed circuit board 9.
Even if the molten solder 21 is attached to the cut end surface of the shield plate 5, the tongue piece 5a can be prevented from being soldered to the case members 2 and 3 of the shield case 4 or the shield plate 5 as follows. it can.

That is, when the shield case 4 is immersed in the molten solder 21 from the side opposite to the projecting side of the tongue 5a, the molten solder 21 causes the surface tension of the molten solder 21 to move the gap g through the tip of the tongue 5a, as shown in FIG. Rise towards. However, when the gap g reaches the base of the tongue piece 5a, its width is widened due to the notch 31, so that the molten solder 21 is prevented from ascending so that it exceeds the notch 31. The tongue 5a cannot be reached.

This prevents the tongue piece 5a from being soldered to the case members 2 and 3 or the shield plate 5. Further, before the printed circuit board 9 is attached, the molten solder 21 is attached to the cut end surfaces of the case members 2 and 3 and the shield plate 5 by immersing the solder in the molten solder 21, so that the electronic components mounted on the printed circuit board 9 are mounted. In 11, the characteristic deterioration of the tuner 1'is prevented only by receiving heat when soldering the terminal.

In the above embodiment, the shield plate 5 is provided near the base of the tongue piece 5a.
The notch 31 is formed as a solder rise prevention portion on the side, but instead of the notch 31 the solder rise prevention portion is provided on the shield plate 5 side (or the case members 2 and 3 side) as shown in FIG. Alternatively, the extruded portion 32 may be formed.

The push-out portion 32 is provided with the shield plate 5 and the shield plate 5.
As shown in FIG. 5, the width of the gap g between the case members 2 and 3 or the contact surface with the other shield plate 5 is set in the vicinity of the base of the tongue piece 5a as shown in FIG. To prevent the molten solder 21 from rising.

Further, instead of the notch 31 and the extruded portion 32 as described above, for example, as shown in FIG. 6, the molten solder 21 rises from the vicinity of the base of the tongue 5a to the tip of the tongue 5a. A notch 33 may be formed in the tongue piece 5a so as to have a width that cannot be provided along the protruding direction.

INDUSTRIAL APPLICABILITY The present invention can be applied not only to a tuner of a cable television but also to a shield case of a high-frequency device such as a video tape recorder or a tuner of an ordinary television receiver.

[Brief description of drawings]

1 is a partial perspective view of an embodiment of a shield case for a high-frequency device according to the present invention, FIG. 2 is an enlarged perspective view of a main part of the shield case for a high-frequency device of FIG. 1, and FIG. 3 is a perspective view of FIG. FIG. 4 is an explanatory view of the function of the solder rise prevention portion in the shield case of the high frequency device, FIG. 4 is an enlarged perspective view of a main part of another embodiment of the shield case of the high frequency device of FIG. 1, and FIG. FIG. 7 is an explanatory view of the function of the solder rise prevention part in the shield case of the high-frequency device, and FIG. 6 is an explanatory view of the action of the solder rise prevention part of yet another embodiment of the shield case of the high-frequency device in FIG. Is a perspective view of a shield case of a conventional high-frequency device, FIG. 8 is a partial perspective view of the shield case of the high-frequency device of FIG. 7 and a printed circuit board attached to the shield case, and FIGS. 9 and 10 are the high-frequency devices of FIG. 7, respectively. Equipment shield case Fig. 11 is an explanatory diagram for mounting the printed circuit board on the board, Fig. 11 is an explanatory diagram for soldering the electronic components mounted on the printed circuit board mounted in the shield case of the high frequency device of Fig. 7, and Fig. 12 is the high frequency device of Fig. 7. It is explanatory drawing of the problem of the shield case of an apparatus. 1, 1 '... Tuner, 2, 3 ... Case member, 4 ... Shield case, 5 ... Shield plate, 5a ... Tongue piece, 6 ... Small chamber, 7 ... Circuit block, 8 ... Coupling part, 9 ... Printed circuit board, 11 ... Electronic parts, 31 ... Notches as solder rise preventing portions, 32 ... Extrusion parts as solder rise preventing portions, 33 ... Notches as solder rise preventing portions.

Claims (1)

[Scope of utility model registration request] 1. A metal case member punched from a metal plate and a shield plate, wherein the case member and the shield plate or shield plates are abutted against each other, and the inside is constituted by the shield plate on a printed circuit board. The circuit block of the high-frequency circuit is divided into a plurality of small chambers, and the shield plate has a tongue whose abutting end projects along the abutting surface of the case member or another shield plate, A shield case for a high-frequency device having a case in which the tongue piece is inserted into a slit formed in a printed circuit board and bent, and is soldered to a land of the printed circuit board. When the molten solder is dipped in the molten solder from the side opposite to the side and pulled up, the molten solder causes the surface tension of the shield plate and the shield plate. The tongue piece is provided with a solder rise preventing portion having a width that prevents a gap existing between the case member or the abutting surface of the shield plate and another shield plate from colliding with each other from rising to the tongue side. A shield case for high-frequency equipment, which is provided in the vicinity of the base of the.