JP2006100473A - Clip for printed wiring board, and structure to be inserted into this clip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable unit for mounting a structure for a printed wiring board, and solve the problem that a small clip for holding and fixing the structure on the printed wiring board for high density mounting is deformed by unsuitable handling, the holding force for the structure is reduced, and the electric contact resistance is increased so that the desired characteristics may be impaired. <P>SOLUTION: This clip is embedded in a clip embedding hole provided in the printed wiring board, so that the size of the upper part of the clip exposed from the printed wiring board is made small to prevent the application of an excessive external force exceeding the elastic stress of the clip to it due to inappropriate handling. Further, even when an excessive force is applied to it, the side surface of the clip is supported by the side wall of the embedding hole, so that the decrease of the holding force due to the permanent deformation of the clip and the increase of the electric contact resistance can be prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a clip structure for sandwiching and fixing a structure on a printed wiring board. Specifically, the clip is embedded in a clip embedding hole formed in a printed wiring board, and the structure is By sandwiching the tongue piece formed integrally with the lower part, deterioration of the mechanical clamping force and electrical connection characteristics of the clip is prevented, and reliability is improved.

In order to meet the demands for downsizing and weight reduction of electronic devices, high-density mounting technology that arranges a large number of circuit components on a printed wiring board is often used. An unexpected oscillation phenomenon occurs when the arranged circuit components are electromagnetically coupled to each other. Alternatively, an unnecessary electromagnetic interference signal is radiated from the conductive foil adhered to the circuit component or the printed wiring board surface, and interferes with other circuits in the same device. In addition, problems such as radiating unnecessary electromagnetic interference signals outside the equipment and disturbing the operation of surrounding electronic equipment may occur particularly in electronic equipment that handles high frequencies. Strict management is required by laws and regulations. However, in the situation where the circuit system is shifting to the digital system, a higher frequency signal component is handled as compared with the analog system, and therefore an accurate technical response for preventing unnecessary radiation is an urgent issue. Yes.

For this reason, a metal clip plate for mounting an electromagnetic interference shield case for an electronic device has been devised, as seen in Japanese Patent Application Laid-Open No. 2000-196280 and Japanese Utility Model Laid-Open No. 2-138500.

FIG. 2 (a) shows an embodiment of the prior art. A perspective view when the shield clip is mounted, (b) is an enlarged perspective view of the shield clip, and (c) is a longitudinal sectional view when the shield clip 2 is mounted on the printed wiring board 3. As shown in FIG. 2A, the shield case 1 is inserted into the shield clip 2 mounted on the surface of the printed wiring board 3 by the reflow soldering technique, so that the shield case 1 is inserted into the four sides. Since the shield clip 2 is mechanically sandwiched by the shield clip 2 and is connected to the ground circuit through the conductive foil adhered to the surface of the printed wiring board 3, the shield case 1 has the shield clip 2 attached thereto. Thus, an unnecessary electromagnetic wave signal from a circuit component housed in the shield case 1 or from outside the shield case 1 is shielded to prevent interference.

FIG. 2B is an enlarged perspective view of the shield clip 2 indicated by a chain line “B” in FIG. The shield clip 2 includes a sandwiching portion 2c that is integrally folded from a bottom plate 2d that is formed of a striation member, and a side plate 2e that allows the shield clip 2 to be gripped by a manipulator of an automatic placement machine. As shown in (c), when mounting on the printed wiring board 3, the bottom surface of the bottom plate 2d of the shield clip 2 is placed on the required portion of the conductive foil 5 of the printed wiring board 3 on the cream solder 6 applied in advance. By reflowing the cream solder 6 in the atmosphere, the shield clip 2 is fixed to the printed wiring board 3 via the solder 6 and an electrical ground circuit is formed.
JP 2000-196280 “Surface-mounted clip for electromagnetic frequency interference shield” 2-138500 “Installation structure of shield case”

  In order to prevent interference with other circuits in the electronic device and peripheral devices due to radiation of unnecessary electromagnetic interference signals from electrical circuit components mounted on the printed wiring board, In order to prevent the circuit portion from receiving interference for the same reason as described above, means for covering the circuit component with a shield case made of a conductive metal and shielding an electromagnetic wave interference signal is used. The shield case is mechanically fixed on the printed wiring board, and the side surface of the shield case is clamped by a shield clip soldered to a conductive foil attached to the surface of the printed wiring board as means for electrically grounding. Due to demands for smaller and lighter electronic devices, the shield clip is also reduced in size, and the shield clip can be easily and permanently deformed due to improper handling, the holding force of the shield case is deteriorated, and the electrical contact performance is impaired. May be. In view of such a situation, the present invention provides a highly reliable attachment device for a printed wiring board structure.

  The clip is exposed from the printed wiring board by embedding the clip mounted on the printed wiring board for holding and fixing the structure on the printed wiring board in the clip embedding hole formed in the printed wiring board. Due to low dimensions and careless handling, the clip's elastic stress is exceeded and excessive external force is prevented from being applied. Even when excessive external force is applied, the clip is formed by the side wall in the buried hole. The side surfaces are supported, and it is possible to prevent a reduction in clamping force and an increase in electrical contact resistance due to permanent deformation of the clip clamping portion. Further, in order to ensure a sufficient insertion length with the clip on the structure side, the clamping force is not reduced by embedding the clip in the embedding hole by providing the tongue piece integrally with the structure.

  By projecting a protrusion on the side of the clip near the top of the side plate for gripping by the manipulator of the automatic placement machine, the shield clip embedded in the embedded hole from the upper surface of the printed wiring board is It is possible to prevent falling off from the buried hole. Further, since the clip bottom portion has a flat structure, it can be surface mounted in the same manner as a conventional product for surface mounting.

  As described above, according to the present invention, since a buried hole for burying a shield clip is formed in a printed wiring board and the shield clip is buried, an external force is applied beyond the elastic stress of the shield clip. In addition, the side walls in the clip embedding hole formed in the printed wiring board support both side surfaces of the shield clip, and it is possible to prevent deterioration of the clip clamping force due to permanent deformation of the shield clip. In addition, since the shield clip is embedded in the clip embedding hole drilled in the printed wiring board while maintaining the height of the shield clip, it is possible to reduce the height of the protruding portion of the shield clip exposed from the surface of the printed wiring board. Further, it is possible to prevent an excessive external force from being applied to the shield clip already attached to the printed wiring board due to careless handling and permanent deformation of the sandwiched portion of the shield clip.

As an embodiment of the present invention, a shield case for shielding electromagnetic interference signals will be described as an example as a sandwiched structure. In FIG. 1A, a shield clip 12 is embedded in a clip embedded hole formed in a printed wiring board 13 constituting the circuit of an electronic apparatus according to the present invention. Shield case tongues 11 a arranged in rows on the lower end sides of the four side surfaces of the shield case 11 are inserted into the sandwiched portion of the shield clip 12, and the shield case 11 is soldered to the surface of the wiring board 13 by the shield clip 12. Is mechanically fixed to the printed wiring board 13 and the shield case 11 is electrically grounded via the shield clip 12 connected to the ground circuit, and the inside and outside of the shield case are shielded against electromagnetic interference signals. .

FIG. 1B is an enlarged perspective view of the shield clip 12 indicated by a chain line “A” in FIG. A sandwiching portion 12c is formed which is integrally folded from the bottom plate 12d formed of a member having sagging properties, and is opposed to each other and presses the shield case tongue 11a. The side plate 12e for gripping the shield clip 12 by the manipulator of the automatic placement machine is folded up integrally from the member of the bottom plate 12d in the same manner as the clamping portion 12c, and the side projection 12a is located near the upper part of the side surface of the side plate 12e. Is folded up.

FIG. 1C is a longitudinal sectional view in which the shield clip 12 is embedded in the embedded hole 14 formed in the printed wiring board 13. A side projection 12a projecting from the side plate 12e of the shield clip 12 from above the buried hole 14 drilled to be equal to or slightly larger than the outer dimension of the bottom surface 12d of the shield clip 12 inserted through the buried hole 14 is a printed wiring board. The shield clip 12 is press-fitted into the embedding hole 14 until it comes into contact with the upper surface.
Since the side protrusion 12e of the shield clip 12 press-fitted into a predetermined position of the embedded hole 14 is in contact with the upper surface of the printed wiring board as described above, it drops out of the embedded hole 14 even before the soldering process. There is nothing.

After the shield clip 12 is inserted into the embedding hole 14, the conductive foil 15 that is attached to the side projection 12 e of the shield clip 12 and the printed wiring board 13 and is electrically grounded is soldered to form a solder fillet 16. Thus, by fitting the shield case tongue 11a to the shield clip 12, the shield case 11 is fixed to the printed wiring board and electrically grounded, and the electric circuit components inside the shield case 11 and the outside are connected to each other. It is electrically shielded, and interference due to electromagnetic wave signals can be prevented.

  After embedding the shield clip 12 in the embedding hole 14 of the printed wiring board 13, the side surface protrusion 12 e of the shield clip 12 and the conductive foil 15 attached to the upper surface of the printed wiring board 13 are soldered, whereby the shield clip 12 Is electrically grounded, and interference due to electromagnetic wave signals can be prevented. As shown in FIG. 1A, since the shield case tongues 11a are arranged in a row so as to protrude from the lower side of the four sides of the shield case, the shield clip 12 is embedded in the printed wiring board 13, and the printed wiring board 13 Although the protrusion height to the upper surface is low, the holding depth of the shield case 11 to be held in the shield clip 12 can be ensured to be equal to that of the prior art.

As described above, by embedding the shield clip 12 in the embedding hole 14 formed in the printed wiring board 13, an excessive external force is inadvertently applied to the holding portion 12 c above the shield clip 12 over the elastic stress. Even in such a case, the side surface of the sandwiching portion 12c is supported by the side wall of the buried hole 14, so that the original shape can be maintained without the sandwiching portion 12c being permanently deformed. Therefore, the shield case 11 is mechanically held. The reliability can be improved without reducing the force and increasing the electrical contact resistance.

Further, since the shield clip 12 is embedded in the printed wiring board 13 and the height of the exposed portion of the shield clip 12 from the printed wiring board 13 is reduced, the shield case 11 is mounted on the printed wiring board 13 with the components mounted. Before the assembly, the shield clip 12 is subjected to an excessive external force exceeding the elastic stress, and the shield clip 12 is permanently deformed, thereby deteriorating the holding force of the shield case 11 by the shield clip 12 and the electrical contact resistance. It is possible to prevent the increase.

As shown in FIGS. 1B and 1C, since the bottom surface 12d of the shield clip 12 is flat, the shield clip 12 according to the present invention is attached to the surface of the printed wiring board 3 of the prior art as necessary. It is also possible to use the same as the shield clip 2 according to the prior art by soldering the pasted conductive foil 5 by reflow soldering.

In the present invention, the shield case is described as an example of the structure attached to the printed wiring board, but the structure is not limited to the shield case, and the printed wiring board is frequently attached and detached for inspection and adjustment. It is also suitable for application to electric circuit parts and mechanism parts to be attached to.

(A) which shows the Example of this invention is a perspective view at the time of shield clip mounting, (b) is an expansion perspective view of a shield clip, (c) is a longitudinal cross-sectional view at the time of shield clip mounting. (A) which shows the Example of a prior art is a perspective view at the time of shield clip mounting, (b) is an expansion perspective view of a shield clip, (c) is a longitudinal cross-sectional view at the time of shield clip mounting.

Explanation of symbols

1: Shield case 2: Shield clip 2c: Holding part 2d: Bottom plate 2e: Side plate 3: Printed wiring board 5: Conductive foil 6: Cream solder 11: Shield case 11a: Shield case tongue 12: Shield clip 12a: Side projection 12c: clamping part 12d: bottom plate 12e: side plate 13: printed wiring board 14: clip embedding hole 15: conductor foil 16: solder fillet

Claims (4)

A printed wiring board clip for sandwiching a structure and fixing on a printed wiring board, the printed wiring board clip being embedded in a printed wiring board clip embedding hole formed in the printed wiring board A printed wiring board clip characterized by the following. 2. The printed wiring board clip according to claim 1, wherein a projection is provided on a side surface of the printed wiring board clip. The printed wiring board clip according to claim 1 or 2, wherein a bottom surface of the printed wiring board clip has a flat structure. 4. A structure inserted into the printed wiring board clip according to claim 1, wherein a tongue piece is protruded at a lower portion.

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