JP3065107U - Electromagnetic shield cover structure - Google Patents

Abstract

(57) Abstract: In a large-sized electronic device having a large housing opening and electromagnetically shielding by a shield cover, the shield cover can be easily attached and fixed to the housing opening, and shields against a predetermined electromagnetic wave. Provided is an electromagnetic shield structure having a structure. The electronic device includes a metallic housing for housing the electronic device, and the housing has at least one opening of a large housing, and a shield cover that fixes the opening and electromagnetically shields the opening. An electromagnetic shield cover structure for shielding electromagnetic waves radiated from the housing opening to the outside,
An elastic structure having conductive elasticity is arranged at a predetermined interval on a contact surface portion provided around the housing opening and a peripheral contact surface of the shield cover which is opposed to and in contact with the shield cover. An electromagnetic shield cover structure having a structure in which, when fixed to a body opening, an electrically conductive contact is made between a contact portion of an elastic structure and a facing surface portion facing the elastic structure.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a relatively large electromagnetic shield structure for electromagnetically shielding over a large electronic device. In particular, when the housing opening of the device body is electromagnetically shielded by a large shield cover, the shield cover can be easily attached and fixed, and can shield a predetermined electromagnetic wave with a predetermined attenuation. About the body.

[0002]

[Prior art]

 Even a large casing (body frame structure) that houses and covers an electronic circuit needs to be provided with a shield structure, for example, so as to conform to the EMC standard. On the other hand, it is necessary to provide a relatively large opening for the convenience of assembly and maintenance. The electromagnetic shield structure is a shield structure for appropriately electromagnetically shielding the large opening.

[0003] The prior art will be described with reference to FIG. As shown in FIG. 4 (a), the main part structure of a large-sized electronic device having a shield structure is a structure in which a large number of screws are used to electrically shield electromagnetically. , A shield cover 20 and a number of set screws 28.

The housing 50 is a main body frame structure that houses and covers an electronic circuit. In addition, a housing opening 52 having a relatively large opening is provided at one or more locations of the housing for convenience in assembling and maintenance.

The casing opening 52 has an annular peripheral contact surface 54 having a width that contacts the flange surface (flange) 22 of the shield cover 20. A predetermined number of screw holes 56 for screwing and fixing at predetermined intervals are provided on the circumferential contact surface 54. FIG. 4 shows a simple structure example in which the housing opening 52 is provided at one place. The size of the opening of the housing is, for example, as large as 2 m in the longitudinal direction. For this reason, the flange surface 22 does not become a flat surface and is liable to bend.

The corresponding shield cover 20 is a metal lid structure provided with a flange surface 22 having an annular flat flange formed on the outer periphery corresponding to the peripheral contact surface 54. Further, as shown in the cross-sectional view of FIG. 4 (b), it is formed in a convex shape to enhance the shape strength. A shield cover that abuts and is fixed to the housing opening 52. The flange surface 22 is provided with a through hole 26 for screwing at a position corresponding to the screw hole 56 of the housing opening 52. Since the size of the shield cover 20 is also large, the flange surface 22 has a curved distortion, so that a gap is easily generated in the mounted state. Therefore, it is necessary to provide the through holes 26 for screwing at a narrow pitch. As a result, there is a disadvantage that it takes time to attach and detach the screws for maintenance and the like.

[0007]

[Problems to be solved by the invention]

 As described above, in the related art, even if there is a curved distortion or unevenness on the entire contact surface between the flange surface 22 on the shield cover 20 side and the peripheral contact surface 54 on the housing opening 52 side, the shield contact can be accurately performed. In order to achieve this, there is provided a structure that is screwed with dozens of setscrews 28. The conventional structure requires a long working time from the viewpoint of assembling and maintenance such as inspection of the internal circuit. There are practical difficulties in this regard. Therefore, a problem to be solved by the present invention is to provide a large electronic device having a large housing opening and electromagnetically shielded by a shield cover so that the shield cover can be easily attached to the housing opening and fixed, An object of the present invention is to provide an electromagnetic shield structure capable of realizing an electromagnetic wave shielding structure.

[0008]

[Means for Solving the Problems]

 In order to solve the above problems, in the configuration of the present invention, a metallic housing 50 for housing an electronic device, and the housing is provided with at least one large opening (for example, a housing opening 52), An electromagnetic shield cover structure that has a shield cover that fixes the housing opening and electromagnetically shields the electromagnetic wave, and shields electromagnetic waves radiated from the housing opening to the outside; An elastic structure having conductive elasticity (for example, a metal tongue piece 32 or a conductive elastic piece 40) is arranged at a predetermined interval on the peripheral surface of the shield cover that is opposed to and in contact with the contact surface portion provided in the above. When the shield cover is fixed to the housing opening, an electromagnetic shield is provided by making electrical conduction contact between a contact portion of the elastic structure and a facing surface portion facing the elastic structure. Do A magnetic shield cover structure. According to the invention, in a large-sized electronic device having a large housing opening and being electromagnetically shielded by a shield cover, the shield cover can be easily attached to the housing opening and fixed, and can shield a predetermined electromagnetic wave. An electromagnetic shield structure that can realize a structure can be realized.

The above-mentioned electromagnetic shield cover structure is characterized in that the elastic structure having elasticity is a metal tongue piece 32 or a conductive elastic piece 40. In addition, there is the above-mentioned electromagnetic shield cover structure characterized in that an elastic structure having elasticity is provided on the shield cover 20 side. Further, there is the above-described electromagnetic shield cover structure, wherein an elastic structure having elasticity is provided on the housing opening 52 side. Further, the above-mentioned electromagnetic shield cover structure is characterized in that the fixing means for fixing the shield cover 20 to the housing opening is fixedly fastened with a screw at a predetermined location or clamped with a clamp structure at a predetermined location. is there.

[0010]

[Embodiment of the invention]

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings together with examples.

The present invention will be described below with reference to FIG. 1, FIG. 2, FIG. 3, and FIG. Elements corresponding to the conventional configuration are denoted by the same reference numerals.

As shown in FIG. 1, the first major structure of the large-sized electronic device having the shield structure of the present invention includes a housing 50, a shield cover 20, and a plurality of setscrews 28. . The screw holes 56 on the peripheral contact surface 54 on the housing side are formed corresponding to the shield cover 20 of the present invention.

Although the shield cover 20 according to the present invention has the same shape, the shield cover 20 has eight through-holes 26 for set screws 28 for fixing the four corners, and is equally spaced at a predetermined pitch A on the flange surface 22. For example, it is a structure in which elastic pressure contact structures 30 arranged at 50 places are formed. In addition, the screwing position shown in FIG. 1 is an example, and is not limited to this. The screwing may be at least a screwing position at which the shield cover 20 can be securely fixed and the metal tongue pieces 32 of all the elastic pressure-contacting structures 30 described later can be elastically pressed with as few as possible.

As shown in FIG. 1B, the elastic pressure contact structure 30 is formed by forming a metal tongue piece 32 in which three sides are cut off in a U-shape on the flange surface 22 and curves the metal tongue piece 32. As shown in FIG. 2 (a), a few millimeters are projected to the lower surface side. Then, as shown in the cross-sectional view of FIG. 2B, in the state where the metal tongue piece 32 is attached to the housing, the projection 34 of the metal tongue piece 32 abuts on the flange surface 22 on the housing side by elastic force (FIG. 2B). (See FIG. 2) to form an electrical contact body that makes electrical contact. In addition, as shown in FIG. 5A, the elastic pressure contact structures 30 may be arranged alternately in two rows on the flange surface 22. Further, as shown in FIG. 5 (b), the gap between the metal tongue piece 32 and the end face of the flange surface 22 (see FIG. 5A) is formed by press working so as to be minimized. It is desirable to minimize the leakage of electromagnetic waves.

Due to the above-mentioned projections 34, all the elastic pressure-contact structures 30 provided around the shield cover 20 and the peripheral contact surface 54 of the housing opening are electrically connected at predetermined pitch intervals A (see FIG. 1A). Contact. At this time, even if there is a height difference due to the bending distortion all around the contact surface, the elasticity of the metal tongue piece 32 makes electrical contact at all points. In addition, a gap is formed at a position other than the contact point, but it is formed at a predetermined pitch interval A so as not to hinder practical use.

Here, the relationship between the predetermined pitch interval A and the electromagnetic shield characteristics will be described. When the contact interval (length of the opening) is P (cm), the attenuation effect amount at the target frequency is S (dB), and the wavelength of the target frequency is λ (cm), P ≒ (λ / 2) × (1 / S). Using this relational expression, for example, when 30 dB attenuation is expected at a frequency of 100 MHz (that is, 300 cm), P = (300/2) × (1/30) = 5 cm, and elasticity is obtained at 5 cm pitch intervals. By forming the press-contact structure 30, a damping effect amount of 30 dB can be obtained. Therefore, the strength and spectrum of the electromagnetic wave radiated from the inside of the housing are measured in advance, and the shield cover 20 having a desired predetermined pitch interval A may be obtained from the relationship between the target frequency and the target attenuation effect amount. This means that electromagnetic shielding can be applied.

As shown in FIG. 3, the second major structure of the large-sized electronic device having the shield structure of the present invention includes a housing 50, a shield cover 20, and a plurality of setscrews 28. . The shield cover 20 according to the present invention has a structure in which the flange-shaped flange surface is omitted, and the top plate flat portion 21 is in contact with the peripheral contact surface 54 on the housing 50 side. Further, as shown in FIG. 3 (b), a concave portion 25 serving as a depression is pressed at a predetermined interval on a back surface side of the contact surface portion that comes into contact with the peripheral contact surface 54 at a predetermined pitch interval, for example, at 50 locations. Form. Then, a conductive elastic piece 40 is attached to the concave portion 25 from the back surface using a conductive adhesive. The conductive elastic piece 40 uses a conductive elastic material that can be depressed by pressing. As a result, when the shield cover 20 is attached and fixed to the housing 50, the conductive elastic pieces 40 can come into contact with the facing peripheral contact surface 54 at all points. Therefore, as described above, by forming the predetermined pitch interval A at a desired pitch interval, a desired amount of attenuation at the target frequency can be obtained.

In the above-described embodiment, the elastic pressure contact structure 30 and the conductive elastic piece 40 have been described as a specific example formed on the shield cover 20 side. It is good also as a structure applied to. Further, the pitch interval A may be a fixed interval, or may be arranged at a different pitch interval in accordance with the frequency band to be attenuated or the radiation intensity of electromagnetic waves radiated from inside. Further, in the above-described embodiment, a specific example in which the fixing of the shield cover 20 is fixed by screwing has been described. However, if necessary, another fixing means such as a clamp structure may be provided at a plurality of locations. The shield cover 20 may be pressed and fixed. Further, in the above-described embodiment, the shield cover 20 is shown as a specific example in which the entire surface is formed of a uniform metal plate. However, if desired, the shield cover 20 may be ventilated to the top plate in accordance with the frequency band and intensity radiated from the inside. A shield cover structure having a possible mesh structure may be used.

[0019]

[Effect of the invention]

 The present invention has the following effects from the above description. As described above, according to the present invention, a large casing is provided with a large casing opening, and in the electromagnetic shield structure covered with the corresponding shield cover, a conductive portion is provided at a portion in contact with the casing side and the shield cover side. An elastic structure (metal tongue or conductive elastic piece) having a certain elasticity is arranged at a predetermined pitch interval, and a structure is provided in which all of them electrically contact. As a result, even if there is a bending distortion between the two, they are contacted with elasticity, so that they are electrically contacted exactly at predetermined pitch intervals. Therefore, there is obtained an advantage that the shield cover can be easily attached and fixed to the housing opening with a small number of screwed portions, and a predetermined electromagnetic shield can be realized.

[Brief description of the drawings]

FIG. 1 is an external view of a shield cover having a large number of elastic pressure-welding structures formed on a flange surface according to the present invention, and a perspective structure example of the elastic pressure-welding structure.

FIG. 2 is a cross-sectional view showing the electrical contact by the elastic pressure contact structure of the present invention.

FIG. 3 is an external view of a case where a shield gasket is attached to the back surface of the shield cover according to the present invention, and a sectional view of attachment of the shield gasket.

4A and 4B are an external view in which a shield cover is attached with a number of setscrews 28 and a cross-sectional side view of the shield cover 20.

FIG. 5 is a perspective view of an example of alternate arrangement in two rows of elastic pressure contact structures of the present invention, and a perspective view illustrating a gap between a metal tongue piece and a flange end face.

[Explanation of symbols]

 REFERENCE SIGNS LIST 20 shield cover 21 top plate flat portion 22 flange surface 25 concave portion 26 through hole 28 screw 30 elastic pressure contact structure 32 metal tongue piece 34 protrusion 40 conductive elastic piece 50 housing 52 housing opening 54 peripheral contact surface 56 screw hole

Claims (5)

[Utility model registration claims] An electronic device includes: a metal housing that houses an electronic device; and a shield cover that has at least one large opening in the housing and that fixes the housing opening and electromagnetically shields the housing. An electromagnetic shield cover structure that shields electromagnetic waves radiated from the housing opening to the outside, wherein a contact surface portion provided around the housing opening and a peripheral contact surface of the shield cover facing and in contact therewith. An elastic structure having a conductive elasticity is arranged at a predetermined interval, and when the shield cover is fixed to the opening of the housing, an electric force is applied between a contact portion of the elastic structure and a facing surface portion facing the elastic structure. An electromagnetic shield cover structure, characterized by comprising a structure for electrically conducting contact. 2. The electromagnetic shield cover structure according to claim 1, wherein the elastic structure having elasticity is a metal tongue piece or a conductive elastic piece. 3. The electromagnetic shield cover structure according to claim 1, wherein an elastic structure having elasticity is provided on the shield cover side. 4. The electromagnetic shield cover structure according to claim 1, wherein an elastic structure having elasticity is provided on the housing opening side. 5. The electromagnetic device according to claim 1, wherein the fixing means for fixing the shield cover to the housing opening is fixedly fastened to a predetermined location by screwing or provided with a clamp structure at a predetermined location. Shield cover structure.