JP2011134779A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus for improving visibility in a heat conductor and preventing displacement. <P>SOLUTION: The electronic apparatus 1 includes a printed wiring board 2 having a prescribed circuit, a mounting component 3 mounted on a surface 2a-side of the printed wiring board 2, a housing 4 arranged on a rear 2b-side of the printed wiring board 2 and the heat conductor 5 arranged to include a region corresponding to a mounting region of the mounting component 3 between the printed wiring board 2 and the housing 4. In the electronic apparatus 1, a through hole 22 is formed in the printed wiring board 2 and the heat conductor 5 is inserted into the through hole 22. Thus, the heat conductor 5 can easily be viewed via the through hole 22 only by viewing the printed wiring board 2 from the surface 2a-side. When vibration or shock is applied to the electronic apparatus 1, for example, movement of the heat conductor 5 to a main face direction is controlled (constrained) in the inserted part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic device.

  As conventional electronic devices, for example, those described in Patent Documents 1 and 2 are known. In the electronic device described in Patent Document 1, heat from an electronic component (heat generating component) mounted on the surface of a circuit board (printed wiring board) is transferred to a heat sink (heat radiator) on the back side of the circuit board ( It is intended to cool the electronic component by transmitting it through a heat conductor. Moreover, in the electronic device described in Patent Document 2, an additional device is connected to the lid (heat radiating body) via a heat radiating silicone rubber (thermal conductor), and the heat of the additional device is transmitted to the lid to radiate heat. It is illustrated.

JP-A-8-204072 JP-A-8-111479

  Here, in recent electronic devices, for example, due to the increasing demand for miniaturization, there is less space around the printed circuit board, so the installation state of the heat conductor (forget to install, misalignment, etc.) It may be difficult to confirm Therefore, in the electronic device described above, it is strongly desired to improve the visibility of the heat conductor. Further, in the above-described electronic device, for example, when vibration or impact is applied, there is a possibility that the heat conductor may be displaced, and as a result, heat generation of the heat-generating component may not be sufficiently performed.

  Then, this invention makes it a subject to provide the electronic device which can improve the visibility in a heat conductor and can prevent position shift.

  In order to solve the above-described problems, an electronic device according to the present invention includes a printed wiring board having a predetermined circuit, a heat generating component mounted on one main surface side of the printed wiring board, and opposite to one main surface of the printed wiring board. The heat dissipating member disposed on the other main surface side and the printed wiring board and the heat dissipating member are provided so as to include a region corresponding to the heat generating component mounting region, and thermally connect the printed wiring substrate and the heat dissipating member. A through-hole penetrating in the thickness direction of the printed wiring board is formed in at least one of the printed wiring board and the heat radiating body, and the thermal conductor enters the through-hole. It is characterized by that.

  In this electronic apparatus, since a through hole is formed in at least one of the printed wiring board and the heat radiating body, and the thermal conductor is inserted into the through hole, at least one of the printed wiring board and the heat radiating body is viewed from the thickness direction. Thereby, a heat conductor can be easily visually recognized through a through-hole. Therefore, it becomes possible to improve the visibility of the heat conductor. In addition, since the heat conductor enters the through hole in this way, it is possible to regulate the movement of the heat conductor in the main surface direction of the printed wiring board. Therefore, it is possible to prevent the positional deviation of the heat conductor.

  Moreover, it is preferable that the installation area | region of a heat conductor is contained in a printed wiring board and a heat radiator in thickness direction view. In this case, since the heat conductor is easily hidden behind the printed wiring board and the heat radiating body and it is difficult to confirm the heat conductor, the above-described effect of improving the visibility of the heat conductor becomes remarkable.

  Moreover, it is preferable that the hue of a heat conductor is made into the hue of the system | strain different from the hue of at least one of a printed wiring board and a heat radiator. In this case, since the heat conductor and at least one of the printed wiring board and the heat radiator are easily identified, it is easy to visually recognize the heat conductor through the through hole. Therefore, the visibility in a heat conductor can be improved further.

  Moreover, it is preferable that a through-hole is a through-hole provided in the printed wiring board. In this case, the through hole can be used as a through hole.

  In addition, a plurality of heat generating components are provided, the heat conductor is provided so as to include a region corresponding to the mounting region of the plurality of heat generating components, and the through hole is located between the plurality of heat generating components in the thickness direction view. It is preferable to be formed as described above. In this case, it is possible to visually recognize the heat conductors for the plurality of heat generating components through the through-holes and to prevent the positional deviation. Further, since the through holes are formed so as to be positioned between the heat generating components when viewed in the thickness direction, for example, even if the heat conductor rotates (rotates out of position) from the through hole as a base point, each heat generating component Since the degree of deviation of the heat conductor with respect to each of the mounting regions is reduced, it is possible to suppress a reduction in the heat dissipation effect of the heat generating component.

  According to the present invention, it is possible to improve the visibility of the thermal conductor and prevent positional deviation.

It is a top view which shows the electronic device which concerns on one Embodiment of this invention. It is sectional drawing along the II-II line of FIG. It is a schematic sectional side view which shows the electronic device which concerns on a modification. It is a schematic sectional side view which shows the electronic device which concerns on another modification. (A) is a top view which shows the electronic device which concerns on another modification, (b) is sectional drawing along the bb line of (a). It is a top view which shows the electronic device which concerns on another modification.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 1 is a plan view showing an electronic apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG. As shown in FIGS. 1 and 2, an electronic device 1 according to the present embodiment is used for an in-vehicle DC-DC converter used in, for example, a hybrid car or an electric vehicle, and is a printed circuit board (PCB: Printed Circuit Board). 2) 2, a mounting component 3, a housing 4 and a heat conductor 5.

  The printed wiring board 2 is a rectangular board-like rigid board having a predetermined circuit, and is a multilayer board including a plurality (here, four) of circuit patterns P1 to P4 arranged in the thickness direction. The circuit patterns P1 to P4 are formed of a metal such as copper and extend in the predetermined region R when viewed from the thickness direction. These circuit patterns P1 to P4 are connected to each other by through holes (through via holes) 21 formed in the predetermined region R. The printed wiring board 2 is fixed to a boss (not shown) erected on the housing 4 with screws or the like, for example.

  The circuit patterns P <b> 2 to P <b> 4 are conductor wirings connecting the mounting component 3 and other circuit components, and are arranged so that a part of the wiring is located between the printed wiring board 2 and the heat conductor 5. Has been. Thereby, the heat of the mounting component 3 can be suitably released from the inner layer circuit patterns P <b> 2 to P <b> 4 of the printed wiring board 2 to the housing 4 through the thermal conductor 5. In the example of FIG. 1, all the circuit patterns P2 to P4 are connected to the through hole 21, but at least one of the circuit patterns P2 to P4 may be connected.

  In the predetermined region R of the printed wiring board 2, a through-hole 22 that penetrates in a circular cross section from the front surface (one main surface) 2 a to the back surface (other main surface) 2 b is provided. In other words, a through hole 22 penetrating in the thickness direction is provided in a portion of the printed wiring board 2 on the heat conductor 5 to be described later. The through hole 22 has a larger diameter than the through hole 21. In addition, the outermost layer of the printed wiring board 2 is covered with a resist (solder resist) 28 except for a portion where soldering is performed, and the hue is composed of a green hue. Therefore, the outer surface of the printed wiring board 2 is dark green. 3 to 5, the resist 28 is omitted for convenience of explanation.

  The mounting component 3 is a heat-generating component such as an electronic component such as a transformer or a coil, or a semiconductor component such as a transistor or a diode, and is mounted on the surface 2 a side of the printed wiring board 2. Specifically, the mounting component 3 is brought into contact with the surface 2a of the printed wiring board 2 in the predetermined region R, and is connected to the circuit pattern P1 on the most surface 2a side among the circuit patterns P1 to P4 via the solder 31. ing.

  Here, the mounting component 3 is disposed so as not to be mounted on the through hole 21 in a direction along the surface 2 a (hereinafter referred to as “main surface direction”) with respect to the through hole 21. That is, the mounting component 3 is disposed in the surface 2 a in the predetermined region R as a mounting region in a region that does not include the through hole 21. The mounted component 3 is connected to the terminal portion 23 of the printed wiring board 2 via the solder 32. As described above, the mounting component 3 includes a high-temperature component in which the component main body is heated due to the influence of the surrounding environment or the like in addition to the high-temperature component in which the component itself is heated during operation as described above.

  The housing 4 is molded from a metal such as aluminum and is disposed on the back surface 2 b side of the printed wiring board 2. The housing 4 has a plurality of meandering grooves (not shown), and dissipates heat of the printed wiring board 2 and the mounting component 3 to the outside by circulating a coolant through these meandering grooves.

  The heat conductor 5 is made of, for example, a silicone resin and has a plate-like outer shape having a predetermined elastic force. The heat conductor 5 is interposed between the printed wiring board 2 and the housing 4 so as to include a region corresponding to the mounting region of the mounting component 3. Specifically, the heat conductor 5 is disposed so as to be included in the printed wiring board 2 and the housing 4 and include the predetermined region R when viewed from the thickness direction, and is disposed in the predetermined region R here. Yes. That is, the installation region of the heat conductor 5 extends in a region narrower than the printed wiring board 2 and the housing 4 while including the mounting component 3, the circuit patterns P <b> 1 to P <b> 4, and the through holes 22 when viewed from the thickness direction. Yes.

  The heat conductor 5 is in contact with the back surface 2b of the printed wiring board 2 and the front surface 4a of the housing 4 and is fixed by being sandwiched between them. Thereby, the heat conductor 5 thermally connects the printed wiring board 2 and the housing 4 while being electrically insulated.

  Further, the outer surface of the heat conductor 5 has a color different from that of the printed wiring board 2, that is, a hue of a system different from that of the printed wiring board 2. The heat conductor 5 here is composed of a pink color hue. “Hues of different systems” mean a difference in color appearance, for example, a color that is conspicuously different when the colors are visually recognized.

  In particular, the heat conductor 5 of the present embodiment enters the through hole 22, and the thickness of the heat conductor 5 in the through hole 22 is thicker than the thickness other than the through hole 22. In other words, the heat conductor 5 rises so that the thickness in the through hole 22 is thicker than the others, and the distance from the surface 2a of the printed wiring board 2 to the heat conductor 5 is reduced. The shape of the portion of the heat conductor 5 entering the through hole 22 is a cylindrical shape that follows the shape of the through hole 22.

  According to the present embodiment configured as described above, the thermal conductor 5 enters the through hole 22 formed in the printed wiring board 2 and the thickness of the thermal conductor 5 in the through hole 22 is other than that. Since it is thicker than the thickness, the thermal conductor 5 can be easily visually recognized through the through-hole 22 only by looking through the through-hole 22 of the printed wiring board 2 from the surface 2a side. In particular, since the distance from the surface 2a to the heat conductor 5 is reduced in the through hole 22, the heat conductor 5 can be visually recognized more easily. Therefore, the visibility of the heat conductor 5 can be improved, and the installation state such as forgetting to install the heat conductor 5 or misalignment can be confirmed.

  In addition, since the heat conductor 5 enters the through hole 22 in this way, for example, when vibration or impact is applied to the electronic device 1, the heat conductor 5 is mainly used in the inserted portion. It is possible to restrict (restrain) the movement in the surface direction, and it is also possible to prevent displacement of the heat conductor 5.

  Therefore, according to this embodiment, the visibility in the heat conductor 5 can be enhanced and positional displacement can be prevented. As a result, it is not necessary to remove the printed circuit board 2 and check the state of the heat conductor 5 each time equipment failure or maintenance occurs, and man-hours can be reduced. Furthermore, in the recent electronic equipment 1, since the space margin around the printed wiring board 2 is reduced, the above-described effect of improving the visibility of the heat conductor is remarkable.

  In the present embodiment, a part of the heat conductor 5 also enters the through hole 21. In this case, since part of the heat conductor 5 that has entered the through hole 21 can be brought into contact with the conductor layer on the inner peripheral surface of the through hole 21, the heat radiation area (heat transfer area) is increased and the mounting component 3 is increased. It becomes possible to enhance the heat dissipation effect.

  Moreover, since the installation area | region of the heat conductor 5 in this embodiment is contained in the printed wiring board 2 and the housing | casing 4 by thickness direction view as mentioned above, the printed wiring board 2 and the housing | casing 4 are included. Since the heat conductor 5 is hidden and it becomes difficult to confirm the heat conductor 5, the above-described effect of improving the visibility of the heat conductor 5 becomes remarkable.

  Further, in the present embodiment, as described above, since the heat conductor 5 has a different hue with respect to the printed wiring board 2, the heat conductor 5 can be easily identified at a glance, The visibility of the conductor 5 can be further enhanced. In addition, as described above, the diameter of the through hole 22 is made larger than the diameter of the through hole 21, and in this respect, the visibility can be further enhanced.

  By the way, although the thermal conductor 5 exceeding the size of the printed wiring board 2 in the thickness direction view may be installed, the thermal conductor 5 is provided for the installation area of the mounting component 3 and the circuit patterns P1 to P4. Even if the installation area is increased, further improvement of the heat conduction effect of the heat conductor 5 cannot be expected. On the other hand, if the installation area of the heat conductor 5 is reduced so that the printed circuit board 2 includes the heat conductor 5 in the thickness direction, the heat conductor 5 is hidden and cannot be seen. . In this respect, in the present embodiment, as described above, the thermal conductor 5 is arranged so as to be included in the printed wiring board 2 in the thickness direction view, and thus the cost of the thermal conductor 5 itself can be reduced. Is also possible.

  Moreover, in this embodiment, since the heat conductor 5 is installed in the predetermined area | region R containing the circuit patterns P1-P4 and the through-hole 22 in thickness direction view, effective heat dissipation is possible. . Furthermore, since the circuit patterns P1 to P4 connected to the mounting component 3 are connected by the through holes 21, the heat dissipation area can be increased, and more effective heat dissipation is possible.

  Moreover, in this embodiment, since the housing | casing 4 serves as a heat radiator (heat radiating member) as above-mentioned, while being able to enlarge a heat radiation area, newly installing a separate heat radiator. Is no longer necessary. In the present embodiment, for example, by forming a conductor layer on the inner peripheral surface of the through hole 22 by plating, the same function as the through hole 21 can be exhibited. That is, the through hole 22 may be a through hole (through via hole), and in this case, the through hole 22 can be used (shared) as a through hole. At the same time, a part of the heat conductor 5 that has entered the through hole 22 and a part of the conductor layer on the inner peripheral surface of the through hole 22 can be brought into contact with each other. This can be further enhanced.

  In the present embodiment, as described above, the mounting component 3 is configured not to be mounted on the through hole 21. That is, the through-hole 21 is provided in a place other than directly below the mounting component 3 in the printed wiring board 2. Therefore, it is possible to prevent the solder 31 from flowing down from the through hole 21, and it is possible to ensure soldering strength and solder reliability.

  If the heat conductor 5 is fixed to the printed wiring board 2 or the housing 4 using an adhesive or the like, the heat conductivity of the heat conductor 5 is reduced and the cost is increased. Since the thermal conductor 5 of the embodiment is only sandwiched and fixed between the printed wiring board 2 and the housing 4, this embodiment is also effective in this respect.

  Incidentally, since the heat conductor 5 has a predetermined elastic force as described above, the heat conductor 5 can also suppress displacement in the thickness direction of the printed wiring board 2 and prevent damage to the mounting component 3 due to vibration. It becomes possible.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above embodiment, one through hole 22 is formed in the printed wiring board 2, but as long as the thermal conductor 5 is in contact with the printed wiring board 2 as shown in FIG. For example, a plurality (two in the figure) of through holes 22 and 22 may be formed, and the heat conductor 5 may enter the through holes 22 and 22.

  In the above embodiment, the through hole 22 is formed in the printed wiring board 2. Instead of or in addition to this, a through hole 41 similar to the through hole 22 is formed in the housing 4 and the through hole is formed. The heat conductor 5 may enter 41 (see FIGS. 3B and 3C). Also in this case, as in the above embodiment, the heat conductor 5 can be easily visually recognized through the through hole 41 by viewing the housing 4 from the back surface 4b side, and the through hole 41 in the heat conductor 5 can be seen. Since the movement of the heat conductor 5 is restricted by the portion that has entered, the visibility of the heat conductor 5 can be enhanced and the displacement can be prevented. At this time, as shown in FIG. 4A, a plurality (two in the figure) of through holes 41, 41 are formed in the housing 4, and the heat conductor 5 enters the through holes 41, 41. Also good.

  Moreover, in the said embodiment, although the heat conductor 5 in the through-hole 22 is made into the column shape, it may be made into a frustum shape as shown in FIG.4 (b), and is made into a dome shape. The shape in the through hole in the heat conductor is not limited.

  Further, as shown in FIG. 4C, a recess 42 may be formed on the surface 4 a of the housing 4, and the heat conductor 5 may enter the recess 42. In this case, the displacement of the heat conductor 5 can be further prevented. Similarly, a recess may be formed in the back surface 2b of the printed wiring board 2, and the heat conductor 5 may enter the recess.

  In the above description, the through holes 22 and 41 penetrating in a circular cross section are formed. However, such a cross sectional shape enhances the visibility of the heat conductor 5 and prevents the positional deviation. If it is a thing, it will not be limited. For example, an oval shape, an oval shape, a rectangular shape, a cross shape that combines long holes, a linear shape, or a shape that combines these shapes may be used.

  Moreover, although the said embodiment is provided with the housing | casing 4 as a heat radiator, it may replace with this and may be provided with the baseplate. Moreover, although the heat conductor 5 of the said embodiment has insulation which electrically insulates the printed wiring board 2 and the housing | casing 4, it does not need to have this insulation, and at least printed wiring Heat may be passed between the substrate 2 and the housing 4. Further, the casing 4 of the above embodiment is a so-called water-cooled type that dissipates heat by circulating a coolant through the meandering groove, but may be a so-called air-cooled type, and the cooling method is limited. It is not a thing.

  Moreover, the mounting component 3 is not limited to a surface mounting component like the said embodiment, A various thing may be sufficient. For example, as shown in FIG. 5, a lead component may be used. In this case, the lead 34 of the mounting component 3 is connected to the circuit pattern P4 and the solder 35, and the lead 34 is thermally connected to the thermal conductor 5 ( Contact). Thereby, the displacement in the thickness direction of the mounting component 3 due to vibration can be suppressed by the heat conductor 5, and lead disconnection or the like can be prevented.

  The electronic device 1 is not limited to the DC-DC converter, but may be a switching power source such as an AC-DC converter. The present invention is applicable to various electronic devices. is there.

  Moreover, in the said embodiment, although the one mounting component 3 is thermally radiated to the housing | casing 4 with the heat conductor 5 of 1 sheet, the number of the mounting components 3 is not limited, For example, as demonstrated below, several The mounted component 3 may be radiated to the housing 4 with a single heat conductor 5.

  FIG. 6 is a plan view showing an electronic apparatus according to a modified example different from those shown in FIGS. As shown in FIG. 6, in the electronic device 50, two mounting components 3 and 3 are mounted in a predetermined region R on the surface 2 a side of the printed wiring board 2. The mounting components 3 and 3 are arranged so as to be shifted from each other in the short direction (vertical direction in the drawing) of the printed wiring board 2.

  The thermal conductor 5 is interposed between the printed wiring board 2 and the housing 4 so as to include both of the regions corresponding to the mounting regions of the mounting components 3 and 3. Specifically, the installation area of the heat conductor 5 includes the two mounting components 3 and 3, the circuit patterns P <b> 1 to P <b> 4, and the through holes 22 as viewed from the thickness direction, and the printed wiring board 2 and the housing 4. It extends to a narrower area.

  The through hole 22 is provided at a position close to each of the mounting components 3 and 3 in the predetermined region R of the printed wiring board 2. Specifically, the through hole 22 is formed so as to be positioned between the mounting components 3 and 3 when viewed in the thickness direction. More specifically, the through hole 22 is viewed from the thickness direction as “each distance from the center of the mounting area of the mounting components 3 and 3 to the center of the through hole 22” <“the mounting components 3 and 3. The distance between each central portion of the mounting area is drilled.

  The electronic device 50 shown in FIG. 6 also has the above-described effect of improving the visibility of the heat conductor 5 and preventing misalignment. In particular, in this case, the thermal conductor 5 for the plurality of mounting components 3, 3 can be prevented from being misaligned while being visually recognized by the single through hole 22. Further, since the through hole 22 is formed so as to be positioned between the mounting components 3 and 3 when viewed in the thickness direction, the heat conductor 5 rotates (rotates out of rotation) with the through hole 22 as a base point (center). Even if it is, the degree of deviation of the thermal conductor 5 with respect to each of the mounting regions of the mounting components 3 and 3 becomes small (that is, even if the deviation angle is the same, the shift distance becomes small). For this reason, it is possible to suppress a reduction in the heat dissipation effect of the mounting component 3.

  In the above description, “located between the mounting components 3, 3” means, for example, not only when positioned between the mounting components 3, 3 in the thickness direction, but also between the mounting components 3, 3. In other words, it includes a positional relationship that can achieve the above-described effect of suppressing the reduction of the heat dissipation effect of the mounting component 3.

  Further, in the present invention, the mounting component 3 may be mounted on the back surface (other main surface) 2b side of the printed wiring board 2, and the mounting component 3 may be a module component. Furthermore, in the present invention, an electronic component, a semiconductor component, or the like may be incorporated and mounted in the printed wiring board 2.

  DESCRIPTION OF SYMBOLS 1,50 ... Electronic device, 2 ... Printed wiring board, 2a ... Front surface (one main surface), 2b ... Back surface (other main surface), 3 ... Mounting component (heat-generating component), 4 ... Housing | casing (heat radiator), 5 ... thermal conductor, 22, 41 ... through hole.

Claims (5)

A printed wiring board having a predetermined circuit;
A heat generating component mounted on one main surface of the printed wiring board;
A radiator disposed on the other principal surface opposite to the one principal surface of the printed wiring board;
A heat conductor that is provided so as to include a region corresponding to a mounting region of the heat-generating component between the printed wiring board and the heat dissipating body, and that thermally connects the printed wiring board and the heat dissipating body,
At least one of the printed wiring board and the heat dissipating body has a through hole penetrating in the thickness direction of the printed wiring board,
The electronic device according to claim 1, wherein the heat conductor enters the through hole.   The electronic device according to claim 1, wherein the installation area of the heat conductor is included in the printed wiring board and the heat radiator when viewed in the thickness direction.   3. The electronic device according to claim 1, wherein the hue of the heat conductor is a hue of a system different from at least one of the hues of the printed wiring board and the radiator.   The electronic device according to claim 1, wherein the through hole is a through hole provided in the printed wiring board. A plurality of the heat generating components;
The thermal conductor is provided so as to include a region corresponding to a mounting region of the plurality of heat-generating components,
5. The electronic device according to claim 1, wherein the through hole is formed so as to be positioned between the plurality of heat generating components in the thickness direction view.

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