JPH06152174A - Structure for shielding electric circuit - Google Patents

Abstract

PURPOSE:To easily assemble the title shielding structure, to easily automate the assembly of the title shielding structure and to make the coupling force of two members extremely strong by a method wherein a claw part is formed at a metal box body, it is inserted into an insertion hole in a metal sheet body and it is bent. CONSTITUTION:A plurality of claw parts 15 formed at bump parts with reference to a metal sheet body 14 for a metal box body 13 are inserted into a plurality of insertion holes 14 made in the metal sheet body 14 so as to correspond to the claw parts 15 from one side of the metal sheet body 14, and they are bent on the other side. Thereby, the metal box body 13 and the metal sheet body 14 are integrated, and the metal sheet body 14 is used also as a mounting member with reference to the outside of an electric circuit 12. The metal box body 13 and the metal sheet body 14 cooperate so as to surround all directions at the circumference of the electric circuit 12, and the electric circuit 12 is shut off electrically at least from the outside. The fixation of the metal box body 13 to the metal sheet body 14 is ensured in such a way that the claw parts 15 at the metal box body 13 are inserted into the insertion holes 16 in the metal sheet body 14 and that their passed parts are bent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal box body for fixing an electric circuit inside to cut off five directions around the electric circuit, and a metal plate body combined with the metal box body to cut off the remaining one direction. And a shield structure for an electric circuit, which surrounds the electric circuit in all directions with the use of and to at least electrically shield the electric circuit from the outside.

[0002]

2. Description of the Related Art (1) Cut off electric wave transmission from an electric circuit to the outside, (2) Cut off magnetic radiation from the electric circuit to the outside, (3) Cut off noise electric wave from the outside to the electric circuit, (4) Blocking noise and magnetism from the outside to the electric circuit, (5) Mechanically supporting the electric circuit to provide a mounting structure for external devices, etc. (6) Connecting each terminal on the electric circuit to the outside Achieve various purposes such as relaying to electrical circuits, (7) protecting electrical circuits from bad external environments such as wind and rain, temperature changes, high humidity, etc. (8) protecting electrical circuits from mechanical shock For this purpose, an electric circuit shield structure is used in which the electric circuit is fixed to the inside and the metal circuit is surrounded in all directions around the electric circuit to at least electrically cut off the electric circuit from the outside.

FIG. 6 is an illustration of an example of a conventional shield structure. Here, a pair of upper and lower bent box-shaped metal boxes are fitted to each other to form a shield structure, and by using a mounting plate member to which the lower metal box is fixed, the electric circuit is connected to an external device. Attached and fixed.

In FIG. 6, the electric circuit 22 is fixed to the upper metal box 23, and the lead wire 27 of the electric circuit 22 is
It is taken out through the bush 28 fitted in the upper metal box 23. The lower metal box 24 is fixed to the mounting plate material 21 using rivets 25, and the upper metal box 2
The protrusion 29 has an insertion limit of 3.

In such a shield structure, the electric circuit 2
By inserting the upper metal box 23 to which the 2 is attached into the lower metal box 24 to the depth of the protrusion 29 and fitting them, an electric shield structure of the electric circuit 22 is formed. Also,
The electric circuit 22 has a plurality of mounting holes 2 formed in the plate member 21.
It is fixed to an external device (for example, the car body of an automobile) by using 6.

[0006]

In the shield structure of FIG. 6, the fitting force of the metal boxes 23, 24 is small, and when the force acts in the direction of lifting the upper metal box 23, the upper and lower metal boxes 23, 24 are easily moved. There is a possibility that the shield state will be lost due to spontaneous separation when exposed to a continuous vibration state. If the metal boxes 23 and 24 are tightly fitted to each other to increase the frictional force, it becomes difficult to assemble them.

Therefore, not only the metal boxes 23, 24 cannot be used as the entire mechanical connecting member, but also the metal boxes 23, 24 cannot be used.
In order to secure the fitting of 24 and to firmly fix the positional relationship of the electric circuit 22 to the plate member 21, another mechanical coupling member (for example, extending from the plate member 21 and screwed to the metal box 23) is used. It is necessary to add rods, screws for interconnecting the metal boxes 23, 24, etc.).

In addition, assembly of the metal boxes 23 and 24 requires high alignment accuracy, and it is necessary to fit the metal boxes 23 and 24 while correcting deformation and the like of the metal boxes 23 and 24. There is a problem that automation cannot be easily implemented.

Further, since the plate material 21 and the metal box 24 are separate members, it is necessary to fix them to each other by using rivets 25 and the like, and at the joint portion between them, the bottom of the metal box 24 and the plate material 2 are connected.
There is much waste of material such as 1 having a double structure.

It is an object of the present invention to construct a shield structure even though the shield structure can be easily assembled, automation of assembly can be easily realized, and a device used for automatic assembly of the shield structure can be simple. It is an object of the present invention to provide a shield structure for an electric circuit in which the coupling force between the two members can be extremely increased and the shield structure itself can be used as it is as a structure for reinforcing and supporting the entire structure.

[0011]

FIG. 1 is an explanatory view of the basic constitution of the invention of claim 1. In FIG. In FIG. 1, a shield structure for an electric circuit according to claim 1 comprises: a metal box body 13 for fixing the electric circuit 12 to an inner side and blocking 5 directions out of 6 directions around the electric circuit 12; In a shield structure for an electric circuit, which is combined with 13 and surrounds all the directions around the electric circuit 12 by using a metal plate body 14 which cuts off the remaining one direction, and which is electrically cut off from the external environment, the metal box body A plurality of claw portions 15 formed at the abutting portion of the metal plate body 14 of the metal plate body 13 have a plurality of insertion holes 16 formed in the metal plate body 14 corresponding to the claw portions 15.
In addition, the metal box body 13 and the metal plate body 14 are integrated by being inserted from one side of the metal plate body 14 and bent at the other side, respectively. The outer surface of the electric circuit 12 also serves as a mounting member for the outside, and has a substantially flat plate-like appearance.

A shield structure for an electric circuit according to a second aspect is the shield structure for an electric circuit according to the first aspect, in which the metal plate has a depth corresponding to the claw portion and greater than a thickness of the claw portion. Then, a recessed portion is formed on the side of the metal box body, and the claw portion penetrating the metal plate body is sunk in the recessed portion to perform the bending.

FIG. 2 is an explanatory view of the basic configuration of the invention of claim 3. 2, the shield structure for an electric circuit according to claim 3 is the shield structure for an electric circuit according to claim 1, wherein the metal plate body 14 has the metal box body corresponding to a side surface of the metal box body 13. A step 32 for restraining the movement of 13 along the metal plate body 14 is formed, and the insertion hole 36 formed corresponding to the claw portion 35 including the step 32 is
The claw portion 35 formed in an opening shape that is narrower than the width of the claw portion 35 on the side of the metal box body 13 and bent toward the outside of the metal box body 13 has the step 32 of the insertion hole 36. It bites into a height position on the way to be locked.

FIG. 3 is an explanatory diagram of a basic configuration of the invention of claim 4. 3, in the shield structure for an electric circuit according to claim 4, in the shield structure for an electric circuit according to claim 1, a distance from the claw portion 15 to a portion where the metal box body 13 abuts against the metal plate body 14 is set. Adjacent to both sides of the claw portion 15 at a distance from each other, the gap formed between the metal box body 13 and the metal plate body 14 is formed at a height that does not cause a problem in terms of the shield effect. The bending of the portion of the metal plate 14 corresponding to the pointed projection 38 to the claw portion 15 absorbs the return of the claw portion 15 after bending.

A shield structure for an electric circuit according to a fifth aspect is the shield structure for an electric circuit according to the fourth aspect, wherein the metal plate body is formed of a material softer than the metal box body, and the claw portion is bent when the metal plate body is bent. The pointed projections pierce the metal plate body by the bias of the metal plate body and the metal box body.

[0016]

In the shield structure for an electric circuit according to claim 1 shown in FIG. 1, the metal box body 13 and the metal plate body 14 cooperate with each other to surround the electric circuit 12 in all directions and to surround the electric circuit 12. At least electrically disconnect from the outside world. The metal box body 13 is fixed to the metal plate body 14 by fixing the claw portion 15 of the metal box body 13.
Is inserted into the insertion hole 16 of the metal plate body 14, and the penetrating portion is bent and secured.

A metal plate body 1 having a substantially flat appearance.
4 is firmly connected to the metal box body 13 and not only constitutes a part of the shield structure, but also fixes the positional relationship between the electric circuit 12 and an external device (for example, a car body), It provides a mounting structure for fixing the whole to an external device, protects the electric circuit 12 from a mechanical shock from the outside, and can also serve the purpose of bearing the weight and load of other devices and members. The metal plate body 14 and the metal box body 13 have a thickness and a shape that satisfy the required mechanical strength according to the added application.

In the electric circuit shield structure according to claim 2,
The metal box body and the metal plate body are fixed in such a manner that the claw portion is submerged in the recess formed in the metal plate body. Therefore, it is not necessary for the bent claw portion to project from the flat surface of the metal plate body located on the opposite side to which the metal box body is attached.

In the shield structure for an electric circuit according to claim 3 shown in FIG. 2, at least a part of the plurality of insertion holes 16 formed in the metal plate body 14 is replaced with a special insertion hole 36. The combination of the special insertion hole 36 and the claw portion 35 preferably faces the metal box body 13 and faces each other.
It is placed in the place.

The step 32 formed on the metal plate body 14 restrains one side surface of the metal box body 13 and the metal plate body 14 and the metal box body 1.
The claw portion 35 that restrains relative movement in the direction intersecting with the step of 3 and is engaged and locked in the side surface of the special insertion hole 36 is
The relative movement of the metal plate body 14 and the metal box body 13 in the direction along the step 32 is restricted. Therefore, the special combination of the insertion hole 36 and the claw portion 35 allows the metal plate body 14 to be inserted even when the claw portion 15 is loosely inserted into another insertion hole 16.
The metal box body 13 is more securely fixed, and a relative slight deviation between the metal plate body 14 and the metal box body 13 is not allowed.

The side surface portion of the special insertion hole 36 is not an extreme taper shape as shown in FIG. 2, but in reality, it is a taper with a slight inclination which can be expected to have a wedge effect, or a pair of parabola parts which are convex upward. , An arc portion or the like. The claw portion 35 penetrates the wide portion of the special insertion hole 36 and projects from the metal plate body 14. The protruding portion of the claw portion 35 is bent toward the lower side of the step 32 while being strongly biased in the direction in which the metal box body 13 and the metal plate body 14 are in close contact with each other. The claw portion 35 has a special insertion hole 36.
The side surface of the special insertion hole 36 also deforms itself while approaching the lower step of the step 32.

In the shield structure for an electric circuit according to claim 4 shown in FIG. 3, the contact between the abutting portions of the metal box body 13 and the metal plate body 14 is concentrated on the pointed protrusions 38. The stress concentration due to the pointed projections 38 significantly increases the frictional force on the metal plate body 14, increases the coupling force between the metal box body 13 and the metal plate body 14, and the relative strength between the metal box body 13 and the metal plate body 14. Control deviation.

Further, at a portion corresponding to the distance from the shoulder opening of the claw portion 15 of the metal plate member 14 to the pointed protrusion 38, a gap is formed between the metal plate member 14 supported by the pair of pointed protrusions 38. It is formed. When the claw portion 15 is bent while being strongly biased in the direction in which the metal box body 13 and the metal plate body 14 are in close contact with each other, the gap is temporarily collapsed, but thereafter, when the claw portion 15 is returned to the bent state. The amount of clearance is restored.
Then, the metal plate body 14 supported by the pair of pointed protrusions 38.
With the rest of the restoring force (spring force), the claw portion continues to be urged toward the metal plate body 14.

In the electric circuit shield structure of claim 5,
For example, a metal plate body is formed of a thick aluminum plate with respect to a metal box body made of stainless steel. When the metal plate body and the metal box body are urged in such a direction that the metal plate body and the metal box body are in close contact with each other when the claw part is bent, the pointed protrusions cut open (or plastically deform) the metal plate body to form a recess in the metal plate body. , The lancet is stably held in this recess. The pointed protrusion cooperates with the recess to generate a strong resistance force against the force in the direction in which the metal plate body and the metal box body are displaced from each other.

When a plurality of claw portions are formed along one side of the metal box body, pointed protrusions are arranged on both sides of two claw portions sandwiching the one claw portion, and a pointed protrusion is formed on the center claw portion. It is possible to select without. Two claw portions sandwiching one claw portion are bent first, and then the central claw portion is bent. The biasing force at the time of bending the central claw portion causes a strong pressure due to the lever action to the pointed projections with the adjacent two claw portions as fulcrums, increasing the bite into the metal plate body. Strong pressure due to leverage can be achieved, for example, by arranging a claw part with a lancet at the center of four sides of a rectangular box metal box and arranging a claw part without a lancet at each end of each side. Can be expected as well.

[0026]

FIG. 4 is an explanatory view of an infrared sensor of the embodiment, FIG.
FIG. 5 is an explanatory diagram of a partial configuration of the infrared sensor of FIG.
In FIG. 4, (a) is a sectional view of the whole, (b) is a detail of the A portion in (a), and (c) is a detail of the B portion in (a). Further, in FIG. 5, (a) is a plan view of the substrate of FIG. 4 (a), and (b) is a detail of the claw portion.

In FIG. 4A, the electric circuit 52 is fixed to a metal box 53, and from the electric circuit 52, through a through hole 69 provided in the box 53, an infrared light emitting diode 71 and a photo diode are externally provided. The sensor 72 is taken out. The infrared light emitting diode 71 and the photo sensor 72 are made of resin.
Objects facing each other through 3 and crossing this facing interval are detected.

The electric circuit 52 is fixed on a pair of convex portions 64 provided on the bottom of the box 53, and the whole electric circuit 52 includes an infrared light emitting diode 71 and a photosensor 72 from a through hole 69 of the box 53. It is pre-molded with the silicon resin 63 filled in the box 53 in the projected state.

The metal box 53 cooperates with the metal bottom plate 54 to form a shield structure that electrically shields the outer circumference of the electric circuit 52 in all directions. The box 53 and the bottom plate 54 are firmly connected by inserting the claw portion 55 of the box 53 into the insertion hole 56 of the bottom plate 54 and bending the part of the claw portion 55 that penetrates the bottom plate 54 on the bottom plate 54.

The box 53 and the bottom plate 54 connected to each other not only form an electrical shield structure, but also bear the mechanical strength of the whole infrared sensor, so that the outer casing 73 and the bottom plate 54 are provided.
A frame structure for fixing the positional relationship of

The metal bottom plate 54 cooperates with the resin exterior 73 to adjust the appearance of the infrared sensor and protects the electric circuit 52, the infrared light emitting diode 71, the photo sensor 72, etc. from the external environment. It also serves as a structure and a mounting member for fixing the infrared sensor to the vehicle body of the automobile. The infrared sensor is adhered to the vehicle body surface of an automobile by applying an adhesive material (or by attaching a double-sided tape) to the flat surface of the bottom plate 54.

In FIG. 4 (b), the opening-like insertion hole 66 formed in the step 62 has a narrow side surface on the side of the box 53, and the claw portion 65 of the box 53 of the box 53 is located at the height of the step 62. It is formed in a tapered shape narrower than the width. Box 53 and bottom plate 54
When the claw portion 65 projecting on the bottom plate 54 is bent toward the lower side of the step 62 while being urged in a direction to bring the claws and the claws into close contact with each other, the claw portion 65 is located at a height position in the middle of the insertion hole 66. It bites into the side surface of the insertion hole 66 and is locked.

In FIG. 4 (c) and FIG. 5 (a), the box 53
The through hole 56 into which the claw portion 55 of the above is inserted is formed in the recess 58 formed in the bottom plate 54. The recess 58 has an area and a depth that can accommodate the bent claw portion 55. The claw portion 55 bent on the bottom plate 54 sinks in the recess 58 and does not project to the plane of the bottom plate 54.

A pair of triangular protrusions 68 sandwiching the claw portion 55 is formed at the edge of the box 53 that abuts the bottom plate 54. The box 53 hits the bottom plate 54 with twice as many triangular protrusions 68 as the total number of the claw portions 55 and 56, and the claw portions 55,
Most of the abutting edges of the box 53, including the shoulders of 56, form a gap with the bottom plate 54. The width of this gap is so narrow that it does not affect the electrical shield of the electric circuit 52.

In FIG. 5A, an insertion hole 56 is formed in a recess 59 into which two of the claw portions 55 formed in the box 53 are to be sunk.
A notch 57 is provided instead of.

In FIG. 5 (b), the claw portion 55 formed in the box 53 has a wide receiving portion 74 at the tip end portion for receiving the push rod of the press machine used for bending the claw portion 55. The bent portion 75 is formed at a stress concentration portion when the receiving portion 74 is biased by the push rod of the press machine. The bent portion 75 is usually formed at a position more than the thickness of the bottom plate 54 from the shoulder portion 76 due to the interference between the bottom plate 54 and the claw portion 55 at the time of bending. At this time, the gap formed between the shoulder portion 76 and the bottom plate 54 is the receiving portion 7 when the urging of the receiving portion 74 by the push rod of the press machine is released.
The kickback of No. 4 is absorbed, and the state where the box 53 and the bottom plate 54 hit each other is guaranteed.

In FIG. 4 (a), the infrared sensor is assembled as follows: (1) The electric circuit 52 is housed in a box 53 to which a resin exterior 73 is fixed in advance, and a silicon resin 63 is filled in the box 5.
It is composed of a step of forming an assembly on the side of 3 and (2) a step of combining and fixing the bottom plate 54 to the assembly on the side of the box 53. Then, the step (2) is automatically performed by using a simple press machine that positions the member on the reference surface of the simple jig and mechanically presses the push rod onto the member.
The bottom plate 54 for the aggregate on the box 53 side in the step (2)
The insertion holes 56 and 67 of the bottom plate 54 shown in FIG.
It is set considerably larger than the cross section of 65. For example, the width of the insertion hole 56 is close to three times the thickness of the claw portion 55, and the clearance between them is close to 1 mm.

It is also possible to manually bend the claw portion 55. Using a hand tool provided with a metal roller at the tip, roll the metal roller in the direction in which the claw portion 55 is bent on the bottom plate 54 to bring the box 53 and the bottom plate 54 into close contact with each other.
Bend 5

By forming the bottom plate 54 of FIG. 5 (a) from aluminum, a stronger joint between the box 53 and the bottom plate 54 can be realized. When the claw portion 55 is bent while the box 53 and the bottom plate 54 are brought into close contact with each other, a pair of hard triangular protrusions 6 that sandwich the claw portion 55 are provided.
8 forms a recess in the soft bottom plate 54 made of aluminum and pierces it, thereby ensuring the electrical connection between the box 53 and the bottom plate 54. Further, a strong mechanical resistance is generated in the direction in which the box 53 and the bottom plate 54 are displaced from each other. However, since aluminum has a lower radio wave shielding effect with the same thickness as iron and stainless steel and a lower strength, the bottom plate 54 needs to be formed to be slightly thick.

[0040]

According to the electric circuit shield structure of the present invention, it is necessary for assembling the metal box body and the metal plate body even though the strong connection between the metal box body and the metal plate body can be easily secured. However, the positioning accuracy of both of them is coarser than that of the conventional example shown in FIG. Therefore, without requiring a precise position detecting device using image processing or a precise positioning device using a ball screw or the like, for example, the member is positioned on the reference surface of a simple jig, and the push rod is attached to the member. The metal box body and the metal plate body can be assembled by using a simple press machine that mechanically presses them down, and the assembling speed is also easy.

Further, the structure composed of the metal box body and the metal plate body has not only an electric shield effect, but also strong mechanical strength. The structure composed of a metal box and a metal plate is (1) a skeleton structure that fixes the positional relationship between parts in the device, (2) a reinforcing structure that bears the mechanical strength of the entire device, and (3) It can also be used as a mounting structure for the outside of the device, and (4) a handling part and a positioning part when assembling and mounting the device. Therefore, the number of parts of the device is reduced, the interference of parts in the device is reduced, the degree of freedom in design is increased, and the miniaturization of the entire device is facilitated.

According to the electric circuit shield structure of the second aspect, since the claw portion sinks in the recess and the claw portion does not project to the flat surface of the metal plate body, the claw portion can be used to scrape other parts or the mounting surface. You don't have to worry about scratches, and the claws won't get caught on the assembly machine or other parts that have accumulated together.
Therefore, assembly troubles and installation troubles of the apparatus are reduced, and personal safety is secured.

According to the electric circuit shield structure of the third aspect, the mechanical strength of the connection between the metal box body and the metal plate body is increased. Therefore, a smaller number of joints, a smaller joint,
It allows the design of devices with thinner materials, and makes assembly of devices including shield structures even easier.

According to the electric circuit shield structure of the fourth aspect, since the pointed projections easily penetrate the oxide film or the coating film on the surface of the metal plate body, the metal plate bodies are electrically joined to each other. Be certain. Further, since the bending return of the claw portion is absorbed by the spring force of the metal plate body in the gap portion supported by the pointed projections, even if a relatively large return material such as stainless steel is used for the metal box body, Bonding between the metal plate bodies is firmly secured, and the resistance force in the direction in which the metal plate bodies are displaced from each other is large. No special post-processing (re-folding, heating, etc.) is required to absorb the return of the claw portion.
Further, since the metal plate members are secured to each other only by the pointed projections, the insertion hole, which is remarkably larger than the cross section of the claw portion, is employed, and the assembling can be further facilitated.

According to the electric circuit shield structure of the fifth aspect, the mechanical strength of the connection between the metal box body and the metal plate body is further increased, and the electrical connection becomes more reliable.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a basic configuration of the invention of claim 1.

FIG. 2 is an explanatory diagram of a basic configuration of the invention of claim 3;

FIG. 3 is an explanatory diagram of a basic configuration of the invention of claim 4;

FIG. 4 is an explanatory diagram of a configuration of an infrared sensor according to an embodiment.

5 is an explanatory diagram of a partial configuration of the infrared sensor of FIG.

FIG. 6 is an explanatory diagram of a configuration of a conventional shield structure.

[Explanation of symbols]

 12 Electric Circuit 13 Metal Box Body 14 Metal Plate Body 15 Claw Part 16 Insertion Hole 32 Step 35 Claw Part 36 Special Insertion Hole 38 Pointed Protrusion

Claims (5)

[Claims] 1. A metal box body (13) for fixing an electric circuit (12) to the inside so as to block 5 out of 6 directions around the electric circuit (12), and the metal box body (13). In a shield structure for an electric circuit, which is combined with a metal plate (14) for cutting off the remaining one direction to surround all the directions around the electric circuit (12) and electrically cut off from the outside world, A plurality of claw portions (15) formed at the abutting portion of the box body (13) with respect to the metal plate body (14),
The metal plate body (14) is inserted into a plurality of insertion holes (16) formed in the metal plate body (14) corresponding to the claw portions (15) from one side and the other side is inserted. After being bent, the metal box body (13) and the metal plate body (14)
And an integrated circuit, and the metal plate body (14) is formed into a substantially flat plate-like appearance that also serves as a mounting member for the outside of the electric circuit (12). Shield structure. 2. The shield structure for an electric circuit according to claim 1, wherein the metal plate body is recessed toward the metal box body at a depth greater than or equal to the thickness of the claw portion corresponding to the claw portion. A recessed structure is formed, and the claw portion that penetrates the metal plate body is sunk in the recessed portion, and the bending is performed. 3. The shield structure for an electric circuit according to claim 1, wherein the metal plate body restrains movement of the metal box body along the metal plate body corresponding to a side surface of the metal box body. A step is formed, and the insertion hole formed corresponding to the claw portion including the step is formed in an opening shape that is narrower than the width of the claw portion on the metal box side, the metal box body The shield structure for an electric circuit, wherein the claw portion bent toward the outer side of the insert bites into and is locked at a height position in the middle of the step of the insertion hole. 4. The shield structure for an electric circuit according to claim 1, wherein the abutting portion of the metal box body against the metal plate body is adjacent to both sides of the claw portion with a distance from the claw portion, The gap formed between the metal box body and the metal plate body has a pointed protrusion formed at a height that does not pose a problem in terms of the shield effect, and from the pointed protrusion in the metal plate body to the claw portion. A shield structure for an electric circuit, characterized in that the bending of the claw portion is absorbed by the bending of the portion corresponding to the above. 5. The electric circuit shield structure according to claim 4, wherein the metal plate body is formed of a material softer than the metal box body, and the metal plate body and the metal box body are bent when the claw portion is bent. A shield structure for an electric circuit, characterized in that the pointed projections are pierced into the metal plate body by biasing.