JP5522215B2 - Electronic control unit - Google Patents

Description

  The present invention relates to an electronic control unit including an electromagnetic wave shielding structure that suppresses electromagnetic wave noise radiated from an electronic device or electronic circuit contained therein from leaking outside a casing.

  Electromagnetic wave noise radiated from an electronic device or an electronic circuit increases in proportion to the square of the frequency at which the electronic device operates. Due to the recent increase in the frequency of electronic device operation, radiated electromagnetic noise is increasing. In addition, standards relating to electromagnetic wave noise radiated from electronic devices have been strengthened, and examples include 2004/104 / EC issued in Europe.

  On the other hand, fitting tolerances for ensuring productivity are indispensable for the parts constituting the casing of the electronic control unit, and it is inevitable that gaps will occur between the parts constituting the casing in the assembled state. It is. For this reason, various shielding techniques have been proposed for reducing electromagnetic wave noise emitted by electromagnetically shielding a gap generated between components constituting the casing of the electronic control unit.

  For example, in the shield case for electronic devices of Patent Document 1, the case main body and the cover are bonded and fixed with a conductive adhesive, and in the portable wireless device of Patent Document 2, the shield case and the base are connected with electric contacts. In the shield structure of the high-frequency unit disclosed in Patent Document 3, by connecting a plurality of locations electrically, a shield wire is provided on the mating surface between the case body and the case lid body, thereby leaking electromagnetic noise from each gap. Is suppressed.

JP 2000-216581 A JP 2001-156484 A JP 2001-135967 A

  However, the technique described in Patent Document 1 requires a step of drying the adhesive in addition to the step of applying the adhesive, and thus the productivity is deteriorated. Even in the technique described in Patent Document 2, a plurality of minute electric contacts must be assembled in the gaps between the parts constituting the casing, and the productivity deteriorates. In the technique described in Patent Document 3, it is necessary to fit the shield member into the groove formed in the case main body or the case lid when assembling, the productivity is poor, and the seal member is accurately attached in the assembled state. There is a problem that it is impossible to visually confirm that the

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic control unit that includes a shielding member that shields electromagnetic wave noise that leaks from a gap between housings, and that can be easily assembled. It is to be.

To achieve the above object, an electronic control unit according to a first aspect of the present invention includes an electronic device or an electronic circuit on which the electronic device is mounted, an opening, and accommodates the electronic device or the electronic circuit inside. A case, a cover that closes the opening of the case, and a shielding member that is formed in a plate shape and a frame shape from a conductive material and is fastened together by the case and the cover and fastening means. It is a frame-like shape that covers the gap generated between the case and the cover by being urged to each of the covers, and a shielding part that maintains the shape alone, a contact part that is energized with at least one of the case or the cover, and the rib portion of a substantially annular is formed in the shielding portion, and wherein the Turkey of having a.

According to this, the electromagnetic wave noise leaking from the gap generated between the case and the cover is absorbed or reflected by the shielding part covering the gap, and the electromagnetic wave noise absorbed by the conductive shielding part is energized with the contact part. It can be dropped to a stable case or cover. Moreover, since the shielding part is maintaining the shape by itself, all the gaps can be covered with one operation, and the productivity of the electronic control unit can be improved.

Moreover, since the shielding part is maintaining the shape by itself, all the gaps can be covered with one operation, and the productivity of the electronic control unit can be improved .
In addition, by fastening the case, the cover, and the shielding member together, an increase in the manufacturing process due to the addition of the shielding member can be suppressed.

  The invention according to claim 2 is characterized in that the case is electrically grounded and the contact portion is energized to the case.

  According to this, since the case is electrically grounded, the electromagnetic wave noise absorbed by the shielding part can be dropped to the grounded side with a more stable potential through the contact part energized with the case.

  In the invention according to claim 3, the shielding member is formed in a plate shape, and the contact portion is a protruding portion that protrudes toward the outer peripheral surface of the side wall of the case, and the shielding member alone is a substantially opposite case. The distance between the vertices of the protrusions that contact the side walls of the protrusions is smaller than the distance between the contact points of the respective protrusions on the side walls. According to this, since the distance between the apexes of the projecting parts that contact the side walls of the case facing each other in the shielding member alone is smaller than the distance between the contact points of the respective projecting parts on the side walls, the projecting parts are assembled. In this state, since the plate is pressed against the outer periphery of the case by the elasticity of the plate, energization between the case and the shielding member can be reliably obtained.

1 is an overall perspective view of an electronic control unit according to an embodiment of the present invention. It is a schematic cross section of the electronic control unit by one Embodiment of this invention. It is the schematic cross section which expanded the characteristic part of the electronic control unit by one Embodiment of this invention. It is a disassembled schematic cross section showing the characteristic structure of the shielding member of the electronic control unit according to an embodiment of the present invention. It is a schematic diagram of the bottom view which shows the position of the projection part installed in the shielding member of the electronic control unit by one Embodiment of this invention. It is a disassembled perspective view which shows the whole structure of the electronic control unit by one Embodiment of this invention.

  Hereinafter, an electronic control unit 100 according to an embodiment of the present invention will be described with reference to the drawings. In addition, this embodiment demonstrates the example applied to the electronic control unit for vehicle-mounted night view systems.

  FIG. 1 is an overall perspective view of an on-vehicle electronic control unit 100 according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view taken along the line II-II in FIG. First, the configuration of the electronic control unit 100 will be described with reference to FIGS. The electronic control unit 100 includes an electronic circuit 4 that is a source of electromagnetic noise, a case 2 that houses the electronic circuit 4, a cover 6 that closes the opening 21 of the case 2, and between the case 2 and the cover 6. It is comprised from the shielding member 8 which covers the gap 11 which arises, and several screws 10a etc. which fasten them.

  What is accommodated in the case 2 may be either the electronic device 42 or the electronic circuit 4 on which the electronic device 42 is mounted as long as it is a source of electromagnetic noise. Hereinafter, in the electronic control unit 100 described in the present embodiment, the electronic circuit 4 on which the electronic device 42 is mounted is used.

  In the present embodiment, the case 2 is formed by aluminum die casting. The material of the case 2 may be iron-based, and the molding method is not limited. As shown in FIGS. 1 and 2, the case 2 is a flat rectangular parallelepiped and has a rectangular opening 21 on the upper surface. On the bottom portion 20 of the case 2, rib portions 22 are formed in a lattice shape, and boss portions 23a and 23b in which screws are cut are provided at a plurality of locations. Further, as shown in FIG. 1, a connector connection opening in which a bracket mounting portion 26 to which a bracket (not shown) for mounting on a vehicle is mounted and a connector 44 to be described later for connecting a signal line to the outside are installed on the side wall 24. Part 25.

  As shown in FIG. 2, the electronic circuit 4 accommodated in the case 2 includes a rectangular printed circuit board 41 on which the circuit is formed, and an electronic device 42 that performs signal processing of a night view system mounted on the printed circuit board 41. Etc. Opening portions 43a and 43b for fastening are provided at a plurality of locations on the printed circuit board 41, and the electronic circuit 4 passes the screw 10b through the opening portion 43b to the boss portion 23b installed on the bottom portion 20 of the case 2. It is fixed by fastening. Here, the circuit formed on the printed circuit board 41 is wired so that the ground side of the circuit is electrically connected to the lower surface side of the opening 43b of the printed circuit board 41, and the electronic circuit 4 is connected to the case 2 by the screw 10b. Are fastened to the bottom surface of the plurality of hole portions 43b on the printed circuit board 41 and the top surface of the boss portion 23b formed on the bottom surface of the case 2. Electromagnetic wave noise generated on the circuit is dropped from the boss portion 23b to the case side.

  As shown in FIG. 1, a plurality of female connectors 44 for connecting external signal lines are installed on one side of the printed circuit board 41 of the electronic circuit 4, and the connectors 44 are attached to the case 2. In the state, it is exposed to the outside from the connector connection opening 25 provided on the side wall 24 of the case 2.

  The cover 6 attached to the opening 21 of the case 2 has a rectangular shape corresponding to the opening 21 and is formed by aluminum die casting. The cover 6 is made of iron. The molding method is not limited. As shown in FIG. 2, the cover 6 is accommodated in the opening 21 of the case 2, and the outer surface 65 of the outer peripheral edge thereof substantially coincides with the opening-side end surface 24 b of the side wall 24 of the case 2 in the height direction. As shown in FIG. 1, a total of six cylindrical recesses 61 are formed in the vicinity of the middle between the four corners and the long side of the rectangle. The cylindrical recess 61 is provided with a fastening seat surface portion 62, and an opening 63 is formed at the center of the seat surface portion 62. The six cylindrical recesses 61 abut on the upper surface of the printed circuit board 41 accommodated in the case 2, so that an internal space 64 is formed inside the printed board 41 and the cover 6. The overall height of the electronic control unit 100 is reduced by the shape in which the electronic device 42 mounted on the printed circuit board 41 is accommodated in the internal space 64 of the cover 6.

  In this embodiment, the case 2 and the cover 6 are formed by die casting made of aluminum. However, regardless of the material of the case 2 and the cover 6 and the processing method, a fitting tolerance is essential for assembly. Therefore, a gap 11 is always generated between the case 2 and the cover 6. In the present embodiment, the gap 11 is about 0.2 mm to 1.0 mm.

  When the signal to be processed is a video signal as in the night view electronic control unit 100, a high-performance electronic device 42 having a high operating frequency is used, and accordingly, an increase in emitted electromagnetic noise and a high frequency range are used. Cause The video signal is easily affected by the electromagnetic wave noise in the high frequency range. When the electromagnetic wave noise leaks from the gap 11, the signal flowing on the signal line (not shown) connected to the connector 44 installed on the side wall 24 of the case 2. It will cause the waveform to be disturbed.

  In this embodiment, as shown in FIG. 2, the shielding member 8 which covers the clearance gap 11 produced between the case 2 and the cover 6 is provided. The shielding member 8 is fastened together with the electronic circuit 4 and the cover 6 to a boss portion 23a installed on the case bottom 20 by a screw 10a.

  Here, the shielding member 8 is demonstrated based on FIG. 3 and FIG.

  The shielding member 8 has a shape covering a gap 11 generated between the case 2 and the cover 6 and includes a frame-shaped shielding plate 81 (see FIG. 1). In addition, this shielding board 81 is corresponded to the shielding part as described in a claim. As shown in FIG. 3, an annular rib portion 82 is formed over the entire circumference on the inner peripheral side of the frame-shaped shielding plate 81. The rib portion 82 increases the rigidity of the frame-shaped shielding plate 81 and can maintain the shape of the frame-shaped shielding plate 81 alone. Further, each side wall 87 of the shielding plate 81 is formed along the side wall 24 of the case 2 on the outer peripheral side of the shielding plate 81. At least one or more projections 88 projecting toward the outer surface 24a are formed on the side surfaces 87 of the side walls 87 on the outer surface 24a side. The protrusion 88 is formed in a hemispherical shape and is in contact with the outer surface 24 a of the case 2.

  As shown in FIG. 4, in the shielding member 8 alone, the distance d between the vertices of the protrusions 88 that contact the side walls 24 of the case 2 that face each other is more than the distance D between the contact points of the protrusions 88 on the side walls 24. Is also formed small. Therefore, as shown in FIG. 3, the side wall 87 of the shielding member 8 bends outward in the assembled state, and the protrusion 88 can be reliably brought into contact with the outer surface 24 a of the case 2.

  A gap 12 is similarly generated between the connector connection opening 25 of the case 2 and the connector 44. As shown in FIG. 1, a part of the side wall 87 extending from the shielding plate 81 extends to the periphery of the connector 44, and covers the gap 12 generated between the connector connection opening 25 of the case 2 and the connector 44. A portion covering the gap 12 extended from the side wall 87 is referred to as a side shield plate 86.

  As shown in FIG. 3, a fixing portion 83 of the shielding member 8 fixed to the concave portion 61 of the cover 6 is formed on the inner peripheral side of the rib portion 82. The fixing portion 83 includes a folded portion 84 having a convex cross section on the upper side, and a seat surface portion 85 that comes into contact with the seat surface portion 62 of the cover 6, and an opening portion 63 of the cover 6 is formed at the center of the seat surface portion 85. An overlapping opening 83a is provided. Further, the folded portion 84 is formed such that the apex 84 a is positioned above the shielding plate 81.

  As shown in FIG. 4, in the shielding member 8 alone, the dimension h from the lower surface of the seating surface portion 85 to the lower surface of the shielding plate 81 is the dimension from the upper surface of the seating surface portion 62 of the cover 6 to the outer surface 65 of the outer peripheral edge portion. It is formed to be smaller than H. As shown in FIG. 3, when the seat surface portion 85 is pressed against the seat surface portion 62 of the cover 6 by the fastening force of the screw 10 a during assembly, the seat surface portion 85 pulls the folded portion 84 downward. Here, since the dimension h of the shielding member 8 described above is formed to be smaller than the dimension H of the case 2, the folded portion 84 is bent. Thereby, the shielding plate 81 can be urged to the outer surface 65 of the outer peripheral edge portion of the cover 6 and the opening side end surface 24 b of the side wall 24 of the case 2. In addition, since the apex 84a of the folded portion 84 is located above the shielding plate 81, the shielding plate 81 is located above the outer surface 65 of the outer peripheral edge of the cover 6 and the opening side of the side wall 24 of the case 2 from above. The end face 24b can be biased almost uniformly. Thereby, generation | occurrence | production of the clearance gap between the shielding plate 81 and the outer surface 65 of the outer periphery part of the cover 6 and the opening part side end surface 24b of the side wall 24 of the case 2 can be suppressed.

  As shown in FIG. 1, bracket mounting portions 26 are formed on two side walls 24 that are not in the longitudinal direction of the case 2, and are mounted on a vehicle by a bracket (not shown) formed of a conductive material. Thereby, the electrical conductivity between the case 2 and the frame portion of the vehicle body is ensured via the bracket.

  As shown in FIG. 5, at least two protrusions 88 of the shielding member 8 are formed so that the two side walls 24 in the longitudinal direction of the side walls 24 of the case 2 are in contact with the vicinity of both ends in the longitudinal direction. . Further, the remaining two side walls 24 including the bracket mounting portion 26 are provided with a protrusion 88 at a central portion or a position biased to one side in order to avoid interference with a bracket (not shown). Further, a protrusion 88 is additionally formed on the side wall 87 in the vicinity where the side shield plate 86 is formed.

  Next, the characteristic operation of this embodiment will be described.

  When current flows through the circuit formed on the electronic device 42 and the printed circuit board 41, electromagnetic noise is emitted from the circuit. Most of the emitted electromagnetic noise is shielded by the case 2 and the cover 6, but a part of the emitted electromagnetic noise tends to leak outside through the gap 11 generated between the case 2 and the cover 6.

  Since the shielding plate 81 covers the gap 11 generated between the case 2 and the cover 6 from the upper surface, electromagnetic noise leaking from the gap 11 collides with the shielding plate 81 and is reflected or absorbed. In a state in which the shielding member 8 is fastened and fixed to the cover 6, the shielding plate 81 is biased almost evenly by the folded portion 84 to the outer surface 65 of the outer peripheral edge of the cover 6 and the end surface 24 b on the opening side of the side wall 24 of the case 2. Since the generation of gaps between the shielding plate 81 and the outer surface 65 of the outer peripheral edge of the cover 6 and the opening side end face 24b of the side wall 24 of the case 2 is suppressed, electromagnetic noise leaking from the gap 11 Can be made to collide with the shielding plate 81, and leakage of electromagnetic noise can be suppressed.

  The projecting portion 88 formed on the side wall 87 of the shielding member 8 and the outer surface 24a of the case 2 are in contact with each other, and the conductivity is ensured. Therefore, the electromagnetic wave noise leaked from the gap 11 and absorbed by the shielding plate 81 Is dropped onto the case 2 via the projection 88 through the side wall 87 of the shielding member 8. As shown in FIG. 3, in the assembled state, the protrusion 88 is pressed against the outer surface 24a of the case 2 by the deflection of the side wall 87. The contact with the outer surface 24a can be maintained, and the conductivity is ensured, so that a certain effect of suppressing magnetic wave noise can be obtained.

  Since the side shield 86 covers the gap 12 formed between the connector connection opening 25 of the case 2 and the female connector 44 from the side, electromagnetic wave noise leaking from the gap 12 is separated from the side shield 86. Colliding and reflected or absorbed. The protrusion 88 formed on the side wall 87 around the side shield plate 86 and the outer surface 24a of the case 2 are in contact with each other, and since electric conductivity is ensured, it leaks from the gap 12 and is absorbed by the side shield plate 86. The electromagnetic wave noise is dropped to the case 2 via the projection 88 through the side wall 87 of the shielding member 8. As shown in FIG. 3, in the assembled state, the protrusion 88 is pressed against the outer surface 24a of the case 2 by the deflection of the side wall 87. The contact with the outer surface 24a can be maintained, and the conductivity is ensured, so that a certain effect of suppressing magnetic wave noise can be obtained.

  Since the case 2 is secured to the frame portion of the vehicle body by a vehicle-mounted bracket (not shown), the case 2 is absorbed from the shielding plate 81 and the side shielding plate 86 of the shielding member 8, and is moved to the case side via the protrusion 88. The dropped electromagnetic wave noise is dropped to the frame of the vehicle body with a more stable potential through the in-vehicle bracket and absorbed.

  In the shielding member 8, the folded portion 84 presses the shielding plate 81 from the upper surface to the outer surface 65 of the outer peripheral edge of the cover 6 and the opening side end surface 24 b of the side wall 24 of the case 2, and the side wall 87 pushes the protrusion 88 of the case 2. It is pressed against the outer surface 24a. Due to this crimping structure, the shielding member 8 does not cause relative movement with respect to the case 2 even when used in a vibration environment such as a vehicle-mounted state, and can prevent the generation of abnormal noise.

  Next, the productivity of this embodiment will be described with reference to FIG.

  FIG. 6 is an exploded perspective view of the present embodiment. In the electronic circuit 4 housed in the case 2 from the opening 21 of the case 2, the screw 10 b that passes through the opening 43 b of the printed circuit board 41 is fastened to the boss 23 b installed on the bottom 20 of the case 2. To be fixed to case 2. The cover 6 is installed on the upper surface of the fixed printed circuit board 41, and the shielding member 8 is assembled from the upper surface. The shielding member 8 is positioned so that the fixing portion 83 is inserted into the concave portion 61 of the cover 6. When the shielding member 8 is assembled to the case 2, it is necessary to expand the projection 88. A temporary load is applied. The screw 10a is passed through an opening portion 83a provided at the center of the fixing portion 83 of the shielding member 8, an opening portion 63 of the cover 6, and an opening portion 43a of the printed circuit board 41 in this order, and is fastened to the boss portion 23a of the case 2. Is done.

  In this embodiment, since the shielding member 8 maintains its shape as a single unit, the positioning of the cover 6 to the recess 61 and the temporary loading of the shielding plate 81 can be performed by a series of operations. Because it is possible, assembly is easy. Since the number of steps increased by the addition of the shielding member 8 is only one operation for assembling the shielding member 8, the electronic control unit 100 with high productivity can be obtained.

  In addition, since the screw 10a fastens all of the case 2, the electronic circuit 4, the cover 6, and the shielding member 8, it is necessary to newly add a fastening part for fixing the shielding member 8, and accordingly Therefore, it is not necessary to newly form a seating surface for fixing the shielding member 8 to the case 2 or the cover 6. Therefore, the number of parts and processing steps associated with the addition of the shielding member 8 do not increase, so that the highly productive electronic control unit 100 can be obtained.

  The shielding member 8 is assembled so as to cover the case 2 and the cover 6 from the outside. Thereby, the assembled | attached state can be confirmed visually. In addition to this visual information, when the shielding member 8 is assembled to the case 2 as described above, the protrusion 88 is expanded and the side wall 87 is elastically deformed, so that the operator can obtain the state as tactile information. Can do. Based on these pieces of information, it is possible to more accurately determine whether or not the shielding member 8 has been correctly assembled.

  The screw 10a tightens all of the case 2, the electronic circuit 4, the cover 6, and the shielding member 8 even when the electronic control unit 100 has a problem or when it is necessary to open the cover 6 for inspection or maintenance. Thus, by removing all the screws 10a, it can be easily disassembled. Moreover, since it is easy to assemble again, maintenance is not deteriorated by adding the shielding member 8.

  When the screw 10a is fastened, a frictional force between the screw 10a and the seating surface portion 85 of the fixing portion 83 of the shielding member 8 generates a moment for rotating the shielding member 8 in the rotational direction in which the screw 10a is fastened. Accordingly, a part of the protrusion 88 provided on the side wall 87 of the shielding member 8 is strongly pressed against the side wall 24 of the case 2. The moment acting on the seat surface portion 85 and the reaction force that a part of the projection 88 receives from the side wall 24 of the case 2 thereby causes the shielding plate 81 to be deformed.

  In this embodiment, among the screws 10a fastened at the six locations shown in FIG. 6, any one of the four screws 10a located at the four corners is fastened first. Here, at least two protrusions 88 of the shielding member 8 are formed so as to be in contact with the vicinity of both ends in the longitudinal direction of the two side walls 24 in the longitudinal direction of the side walls 24 of the case 2. By first fastening any one of the four screws 10a, the rotational moment generated in the shielding member 8 when the screw 10a is fastened is formed on the opposite side or the diagonal position in the longitudinal direction with respect to the fastening position. It can be received by the protrusion 88. Since the distance from the rotational moment acting position to the projection 88 where the reaction force is generated is large, the absolute value of the reaction force can be reduced and the deformation of the shielding member 8 can be suppressed. The screw 10a fastened at the second location is assumed to be at a diagonal position of the screw 10a fastened first. In this case, the rotational moment generated in the shielding member 8 when the screw 10a is fastened is received by the first fastening portion at a diagonal distance, so that the absolute value of the reaction force can be similarly reduced. Can be suppressed.

2 cases, 4 electronic circuits, 6 covers, 8 shielding members, 10a screws, 10b screws, 11 gaps, 12 gaps, 21 openings, 22 ribs, 23a bosses, 23b bosses, 24 side walls, 24a outer surfaces, 24b Opening side end face, 25 Connector connection opening, 26 Bracket mounting part, 41 Printed circuit board, 42 Electronic equipment, 43a Opening part, 43b Opening part, 44 Female side connector, 61 Recessed part, 62 Seat surface part, 63 Opening Part, 64 internal space, 65 outer surface, 81 shielding plate (shielding part), 82 rib part, 83 fixing part, 83a opening part, 84 folding part, 84a folding part vertex, 85 seat surface part, 86 side shielding plate, 87 Side wall, 88 protrusion (contact part), 100 electronic control unit

Claims (3)

An electronic device or an electronic circuit in which the electronic device is mounted;
A case having an opening and housing the electronic device or the electronic circuit therein;
A cover that closes the opening of the case;
A plate-like and frame-like shape made of a conductive material, and a shielding member that is fastened together by the case and the cover and fastening means,
The shielding member is
A shield- like shape that is biased toward each of the case and the cover and covers a gap formed between the case and the cover, and that maintains the shape alone ;
At least the contact portion of either the one energized before SL case or the cover,
An electronic control unit, wherein the Turkey of having a rib portion of the substantially annular, formed in the shielding portion contact and.   The electronic control unit according to claim 1, wherein the case is electrically grounded, and the contact portion is energized to the case. The shielding member is formed in a plate shape,
The contact portion is a protrusion protruding toward the outer peripheral surface of the side wall of the case,
The shielding member alone is formed in a frame shape such that the distance between the apexes of the protrusions that contact the side walls of the case that are substantially facing each other is smaller than the distance between the contact points of the protrusions on the side walls. The electronic control unit according to claim 1, wherein a substantially annular rib portion is formed in the shielding portion .

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