JP5311063B2 - Vehicle electronic device - Google Patents

Description

  The present invention relates to a vehicular electronic device in which a wiring board on which a plurality of elements are mounted is housed in a case.

  Some electronic devices in which multiple or multiple types of elements mounted in a case are housed in a case require heat dissipation beyond a certain level for some types of elements. The heat accumulated in the space needs to be discharged to the outside. For example, the synthetic resin case described in Patent Document 1 has a plurality of rooms formed by partitioning the inside with partition walls, and a heat dissipation path that leads from each of the rooms to the slit is provided, and heat is discharged outside through the slit. doing.

Japanese Utility Model Publication No. 4-59887

  However, providing a slit means that the inside of the case is exposed to the outside air, and in this case, an irrelevant portion that does not require heat radiation is also affected by the outside air. As a result, an element that is easily affected by outside air is a factor that shortens its life, and the replacement cycle is likely to be shortened. Specifically, there is a migration problem caused by moisture contained in the outside air. This migration problem becomes more apparent as the arrangement density of elements / wirings on the wiring board becomes denser and the element size becomes smaller. The problem becomes more important as it becomes denser and smaller.

  The subject of this invention is providing the electronic device for vehicles provided with the case which can solve both the problem of heat dissipation and the problem by external air.

Means for Solving the Problems and Effects of the Invention

In order to solve the above problems, an electronic device for a vehicle according to the present invention includes:
A wiring board on which a plurality of elements are mounted is accommodated in the case, and the internal space of the case communicates with a vent provided in the outer wall portion of the case and requires heat dissipation mounted on the wiring board. The heat-dissipating chamber is formed to extend so as to include predetermined heat-dissipating elements, and is not in communication with all the vents and heat-dissipating chambers provided in the case, but also by outside air mounted on the wiring board. An isolation room containing a predetermined outdoor air aversion element that is susceptible to adverse effects is partitioned by a partition wall ,
The heat dissipating element and the external air aversion element are mounted on the same surface of the wiring board, and the heat dissipating chamber and the isolation chamber are formed in a line along the surface .

  According to the configuration of the present invention, in the case, the heat radiating chamber connected to the outside air through the vent and the isolation chamber separated from the outside air are separated from each other. By disposing an aversion element (for example, a humidity aversion element), it is possible to solve both the problem of heat dissipation and the problem of an adverse effect due to outside air. In addition, the improvement of heat dissipation has been achieved with respect to electronic components that have been mounted on a wiring board in a way that requires heat dissipation / exhaust means, such as a heat sink, even if there is no heat dissipation / exhaust means. It is also possible to prevent problems. Thereby, the arrangement area of the heat dissipating means and the heat exhausting means from the wiring board becomes unnecessary, and the wiring board can be miniaturized correspondingly.

  Here, the predetermined heat dissipation element is a regulator IC, a temperature rise such as a power intelligent IC or a power supply IC having a well-known temperature rise protection means (protection function based on the detection result of the temperature detection unit). It is an element used together with a heat-dissipating means / heat-dissipating means such as a heat-resistant element such as a protection function element, a lighting limiting resistance element, a power source reverse connection prevention diode, and a heat sink. Furthermore, an element having a heat generating property equivalent to or higher than these can be included. On the other hand, the predetermined outdoor air aversion element is an element having an element size of 2125 or less (for example, a chip capacitor or a chip resistor), a through hole group including two or more through holes having a distance of 1.5 mm or less, and the like. Such a moisture aversion element. Furthermore, it is possible to include elements that are susceptible to adverse effects due to moisture, equivalent to or higher than these, and further, not only moisture but also adverse effects due to other components contained in the outside air are equal to or more than the above-mentioned moisture aversion elements. Other elements that are susceptible to exposure can also be included.

  The case in the present invention includes a bottom surface portion and an outer peripheral wall portion that rises from the outer peripheral side of the bottom surface portion and surrounds the inner space, and the wiring board is formed on the partition wall portion formed in the inner space. It can arrange | position in the form which covers a part or all of. According to this configuration, since the heat radiating chamber and the isolation chamber formed so as to be open on one side are covered with the wiring board, gas movement to another space can be more unlikely to occur. For example, if at least all the isolation chambers are covered with the wiring board, the adverse effects of the elements inside the device due to outside air can be further reduced.

  In the case of the present invention, the vertical position relationship when the vehicle is mounted is determined in advance, and the vent is formed on the lower end side outer wall portion of the case (the outer wall portion on the lower end side determined by the above vertical position relationship). It can have an air flow inlet and an external air flow outlet formed on the upper end side outer wall portion (the upper wall portion on the upper end side defined by the above vertical position relationship) of the case. According to this configuration, the movement of heat from the lower side to the upper side can be promoted with respect to the gas in the heat dissipation chamber, and the heat can be discharged more efficiently.

  In the present invention, the wall portion surrounding the heat radiating chamber can be formed in a form toward the outside air flow outlet without stopping the flow of gas that naturally rises as the temperature rises in the heat radiating chamber. For example, if the gas that has absorbed heat falls into a bag path in the heat dissipation chamber due to natural rise, heat accumulates at that portion, so the heat dissipation chamber is formed as a heat dissipation path that does not generate a bag path, so Increases heat dissipation.

  The case in the present invention can be configured to have a bottom surface portion and an outer peripheral wall portion that rises from the outer peripheral side of the bottom surface portion and surrounds the internal space, as described above. In this case, the wall portion surrounding the heat radiating chamber can include a part of the bottom surface portion, the partition wall portion, and the outer peripheral wall portion, and the heat radiating chamber can be formed along the outer peripheral wall portion. . By forming the heat radiating chamber along the outer peripheral wall portion, a long heat radiating path can be formed, so that it is not necessary to form many partition wall portions, which leads to a reduction in the overall cost. Further, since the vent can be formed in the outer peripheral wall portion of the case, the vent can be provided in the middle of the heat dissipation path. Therefore, if a heat radiating chamber is formed along the outer peripheral wall portion, a heat radiating path with good exhaust efficiency can be formed.

  In the present invention, the heat radiating chamber is formed in the outer peripheral wall portion on the lower end side of the case so that the gas flow that naturally rises as the temperature rises in the heat radiating chamber does not stay, and is directed to the external airflow outlet. A heat dissipation path from the external air flow inlet formed to the external air flow outlet formed in the outer peripheral wall portion on the upper end side of the case, and one intermediate between the outer peripheral wall portion on the lower end side and the outer peripheral wall portion on the upper end side It can comprise so that it may have an outer peripheral wall part as a part of wall part surrounding this thermal radiation chamber. According to this configuration, it is possible to form a relatively large heat radiation chamber that forms a heat radiation path from the lower end side outer wall portion of the case through the intermediate outer peripheral wall portion to the upper end side outer peripheral wall portion. Since this heat radiating chamber is a space that continues continuously along the outer peripheral wall portion, it is possible to provide a vent in the middle of the space, and a heat radiating path with good exhaust efficiency can be formed.

  When at least the outer peripheral wall portion on the lower end side and the intermediate outer peripheral wall portion are part of the wall portion surrounding the heat radiating chamber, the heat radiating chamber is provided on the outer peripheral wall portion on the lower end side in the external air flow inlet. The inner wall surface at least on the intermediate outer peripheral wall portion side of the partition wall portion facing the opening on the upper side can be formed as an inclined surface that rises and inclines toward the intermediate outer wall portion. According to this configuration, the gas that naturally flows in from the external air flow inlet of the lower end side outer peripheral wall portion is efficiently promoted to the region where the intermediate outer peripheral wall portion is located in a form guided by the inclined surface. It can be led to the air flow outlet.

  When at least the outer peripheral wall portion on the upper end side and the intermediate outer peripheral wall portion are part of the wall portion surrounding the heat radiating chamber, the case has an upper corner portion connecting the intermediate outer peripheral wall portion and the outer peripheral wall portion on the upper end side. Can be formed as a chamfered portion (upper side chamfered portion), and the inner wall surface of the upper side chamfered portion on the heat radiation chamber side can be formed as an inclined surface that rises and slopes toward the outer peripheral wall portion on the upper end side. According to this configuration, the gas that naturally rises in the vicinity of the intermediate outer peripheral wall portion is efficiently urged to the region where the upper end side outer peripheral wall portion is located in the form guided by the inclined surface, and is led to the external airflow outlet. Can do.

  In the case of the above configuration, the lower corner portion connecting the intermediate outer peripheral wall portion and the outer peripheral wall portion on the lower end side is formed as a lower side chamfered portion, and the lower side chamfered portion is formed in the circumferential direction of the outer peripheral wall portion. The length can be formed shorter than the formation length of the upper side chamfer. The upper corner is advantageously formed as a large inclined surface to promote the rise of the internal gas. On the other hand, the lower corner portion of the other has a larger volume in the case as the size of the chamfered portion is smaller. Therefore, a wiring board having a larger area can be arranged, and more elements are arranged on the wiring board. It becomes possible to arrange.

The perspective view of the case of the electronic device for vehicles which makes one embodiment of the present invention. The perspective view which looked at the case of FIG. 1 from another angle. The top view of the case of FIG. 1, a front view, a rear view, and a left-right side view. The bottom view of the case of FIG. The figure which showed the top view of the case of FIG. 1 simply. The figure which showed simply an example of the wiring board 10 accommodated in the case of FIG. 1 is a cross-sectional view schematically showing a state in which a case and a wiring board are assembled, which is an electronic device for a vehicle that constitutes an embodiment of the present invention.

  Hereinafter, one embodiment of an electronic device for vehicles of the present invention is described using a drawing. FIG. 1 is a perspective view in which the inside of a housing space of a case in which a wiring board on which a plurality of types of electronic components (elements) are mounted is accommodated in the case, and FIG. 2 is a housing of the case of FIG. It is the perspective view which looked at the case back side which cannot visually recognize the space inside. 3 is a front view, a rear view, a left and right side view, and a plan view of the case of FIG. 1, and FIG. 4 is a bottom view of the case of FIG. 5 is a diagram schematically showing a plan view of the case of FIG. 1, FIG. 6 is a diagram schematically showing an example of a wiring board disposed in the case, and FIG. FIG. 6 is a cross-sectional view schematically showing a cross section of the vehicle electronic device in which the wiring board of FIG. 6 is disposed in the case of FIG. 5. In the following description, the description will be made mainly with reference to FIGS. 5 to 7, which schematically show FIGS. 1 to 4, but these descriptions also apply to FIGS. 1 to 4. I can say that.

  The vehicular electronic device 1 of the present embodiment constitutes a part of a vehicular display device (here, a meter display device), and a wiring board 10 is accommodated in the case 2 as shown in FIG. It is composed in the form. The case 2 includes a bottom surface portion 21 and an outer peripheral wall portion 22 that rises from the outer peripheral side of the bottom surface portion 21 and surrounds the internal space 30, and is an outer wall portion that includes the bottom surface portion 21 and the outer peripheral wall portion 22. 20, an internal space 30 that is open in one direction is formed in the case 2.

  On one or both main surfaces of the wiring substrate 10, a plurality of / multiple types of elements are mounted. Among these elements, there are elements (unit parts) that generate heat during driving and require heat dissipation, predetermined elements (unit parts) that are easily affected by exposure to the outside air, and other elements. Is included. In the case of FIG. 6, various elements (reference numerals 8, 9, etc.) are arranged on the back side of the illustrated wiring board 10.

  In the present embodiment, as a predetermined element (heat dissipating element / heat dissipating electronic component) 8 that needs to be dissipated mounted on the wiring board 10, a regulator IC, a well-known temperature rise protection means (temperature detecting unit) It defines elements such as power intelligent ICs and power supply ICs that have protection functions based on detection results), lighting limiting resistance elements, power supply reverse connection prevention diodes, and other elements that are mounted with heat sinks (heat sinks) and fans. . On the other hand, as a predetermined element 9 (outside air aversion element / outside air aversion electronic component) that is likely to be adversely affected by outside air mounted on the wiring board 10, an element having an element size of 2125 or less (for example, a chip capacitor or a chip resistor), A through-hole group consisting of two or more through-holes having an interval of 1.5 mm or less is defined. Note that the outside air aversion element (moisture aversion electronic component) 9 here is an element that is susceptible to adverse effects (migration) due to moisture contained in the outside air, and can also be referred to as a moisture aversion element.

  In contrast to the case 2 that accommodates the wiring board 4 in which the heat radiating element 8 and the outside air aversion element 9 are mixed, in the present embodiment, the vent 3 is provided in the outer wall portion 20 of the case 2. The internal space 30 of the case 2 communicates with the vent 3 and is not in communication with the heat radiating chamber 38 containing the heat radiating element 8 and all the vents 3 provided in the case 2. The isolation wall 39 containing the outside air aversion element 9 is partitioned and separated by the partition wall 4.

In the vehicle electronic device 1 of the present embodiment, the vertical positional relationship when the vehicle is mounted is determined in advance. Accordingly, the vertical positional relationship when the vehicle is mounted on the case 2 is also determined. Here, the outer peripheral wall portion 23 is determined to be on and the outer peripheral wall portion 24 is determined to be on the lower side. In the heat radiating chamber 38, the internal gas temperature is increased by the heat generated from the heat radiating element 8, and accordingly, a gas flow that naturally rises is generated. For this reason, it forms in the form which has the vent hole 3 located in the downward direction, and the vent hole 3 located in the upper direction, and external air flows in from below and absorbs heat in the heat radiating chamber 38. A gas flow is formed in which the discharged gas is discharged from above and functions as a heat dissipation path. The vent 3 may be formed only on the outer peripheral wall portion 22, but if possible, the opening is widened by forming it as a continuous opening from the outer peripheral wall portion 22 to the bottom surface portion 21. Can be increased. In the heat radiation chamber 38, if the gas that has absorbed heat moves into the bag path where it has moved due to natural rise, heat accumulates at that portion, resulting in poor exhaust heat efficiency. For this reason, the heat radiating chamber 38 is preferably formed so as to form a heat radiating path that does not generate such a narrow path as much as possible.

  By the way, the wiring board 10 is disposed on the partition wall portion 4 formed in the internal space 30 so as to cover a part or all of the internal space 30. Here, the wiring board is placed on the front end surface of the partition wall portion 4 (the protruding front end surface opposite to the bottom surface portion 21). Further, the surface 22a on the inner peripheral side 22A of the distal end portion (projecting end portion opposite to the bottom surface portion 21) of the outer peripheral wall portion 22 of the case 2 has the same height as the distal end surface 4a of the partition wall portion 4, The front end surface 4a is also a mounting surface on which the wiring board 10 is mounted. The outer peripheral side of the distal end portion of the outer peripheral wall portion 22 protrudes from the inner peripheral surface side in order to prevent the lateral displacement of the wiring board 10 placed on the inner peripheral side, and functions as a misalignment preventing portion 22B. Yes. Here, the entire internal space 30 is covered with the wiring board 10. Since all the isolation chambers 39 are covered with the wiring board 10, adverse effects due to the outside air of the internal elements are reduced.

  The wiring board 10 arranged on the case 2 in this manner is fixed to the case 2 by a plurality of fastening members 6 (here, screws) as shown in FIG. The wiring board 10 is formed with a through hole 19 for allowing the fastening member (screw) 6 to pass therethrough. On the other hand, the case 2 has a plurality of fastening holes (here, screws) for fixing the fastening member 6. Hole) 29 is formed, and the distal end surface 28a of the fastening hole outer peripheral portion 28 surrounding the fastening hole 29 is also placed on the mounting surface on which the wiring board 10 is placed, similarly to the distal end surface 4a of the partition wall portion 4. It has become.

  On the wiring board 10 are also formed a connector 7 for connection with a vehicle, an inspection land 6 for use in factory inspection, and the like, and a relatively large opening 31 provided in the case 2 is formed. These holes are provided so that the connectors 7 can be connected and the inspection land 6 can be touched. Here, the position on the wiring board 10 corresponding to the rectangular opening 31 is the mounting portion of the connector 7, and the position on the wiring board 10 corresponding to the substantially elliptical opening 31 is the inspection land (a plurality of circular portions arranged side by side). ) 6 forming part.

  Further, as shown in FIGS. 1 to 5, ribs 22 </ b> R and 4 </ b> R for reinforcing the strength are formed in the actual case 2. In addition to the ribs 22R continuously connected from the outer peripheral wall 22 to the inner peripheral side, there are also ribs 4R continuously connected from the partition wall 4 described above. However, each of the ribs 22R and 4R is formed to have a height lower than that of the partition wall portion 4 at least in the heat radiation chamber 38, and does not partition or divide the internal space 20 unlike the partition wall portion 4. . In particular, the ribs 22R and 4R formed in the heat radiation chamber 38 are preferably formed low so as not to be a factor for forming the above-mentioned bag path. Here, all the ribs 22 </ b> R and 4 </ b> R are formed lower than the protruding height of the partition wall portion 4 (height from the bottom surface portion 21 to the tip).

  In the present embodiment, two types of heat radiation chambers are provided. One is an outer peripheral heat radiation chamber 38 </ b> A formed along the outer peripheral wall portion 22 and island-shaped heat radiation chambers 38 </ b> B scattered in the isolation chamber 39. Here, one outer peripheral heat radiation chamber 38A, a plurality of island-shaped heat radiation chambers 38B, and one isolation chamber 39 are provided. Hereinafter, the heat radiation chambers 38A and 38B and the isolation chamber 39 will be described in detail.

(Outer peripheral heat radiation chamber 38A)
The outer peripheral heat radiating chamber 38A is a heat radiating chamber formed so as to sequentially include the above-described heat radiating elements 9 along the outer peripheral wall portion 22, and is formed as a relatively long heat radiating path from below to above. The The outer peripheral heat radiation chamber 38 includes a part of the bottom surface portion 21, the partition wall portion 4, and the outer peripheral wall portion 22 as a wall portion surrounding the outer peripheral heat radiating chamber 38. A heat radiation path is formed from the formed external airflow inlet 34 along the outer peripheral wall portion 25 toward the external airflow outlet 33 formed in the upper end side outer peripheral wall portion 23 of the case 2. That is, the outer peripheral wall portion 22 constituting the outer peripheral heat radiation chamber 38 includes a lower end side outer peripheral wall portion 24, an upper end side outer peripheral wall portion 23, and an intermediate outer peripheral wall portion 25 connecting these 23, 24. It is a part of a wall portion surrounding the heat radiation chamber 38A. Note that the outer peripheral heat radiation chamber 38A in the present embodiment includes only one intermediate outer peripheral wall portion 25 as a wall portion in the left and right direction of the case 2 whose vertical direction is predetermined, and the other forms an isolation chamber 39. It is a wall.

The vent hole 3 communicating with the outer peripheral heat radiation chamber 38A is an outer portion formed on the lower end side outer wall portion 20 of the case 2 (the lower end side outer wall portion 20 defined by the above vertical position relationship: here, the lower end side outer peripheral wall portion 24 ). It is formed in the air flow inlet 34 and the external air flow outlet 33 formed in the upper end side outer wall portion 20 of the case 2 (the upper end side outer wall portion 20 : here the upper end side outer peripheral wall portion 23 defined by the vertical position relationship). As described above, efficient heat discharge is realized by utilizing the gas flow that naturally rises. The vent 3 is also provided in the middle of the heat radiation path formed by the outer peripheral heat radiation chamber 38A.

  Further, in the outer peripheral heat radiation chamber 38A, the inner wall surface 4b on the side of at least the intermediate outer peripheral wall portion 25 of the partition wall portion 4 facing the opening 3 provided on the lower end outer peripheral wall portion 24 of the outer air flow inlet 34 on the upper side. , Formed as an inclined surface that rises and inclines toward the intermediate outer wall portion 20. Thereby, the gas which flows in from the external air flow inlet 34 of the lower end side outer peripheral wall portion 24 and naturally rises is urged upward in the form of being guided to the inclined surface 4 b, and can be efficiently guided to the external air flow outlet 33. .

  Further, the case 2 has a chamfered upper corner portion 26 that connects the intermediate outer peripheral wall portion 25 and the upper end side outer peripheral wall portion 23 and a lower corner portion 27 that connects the intermediate outer peripheral wall portion 25 and the lower end side outer peripheral wall portion 24. Parts (upper side chamfer 26, lower side chamfer 27). Then, by forming the inner wall surface 26a on the heat radiation chamber 38 side of the upper side chamfer 26 as an inclined surface that rises and inclines toward the upper end side outer peripheral wall portion 23, the gas that naturally rises in the vicinity of the intermediate outer peripheral wall portion 25 is generated. Then, it is urged to the upper region where the upper end side outer peripheral wall portion 23 is positioned in the form of being guided by the inclined surface 26 a, and can be efficiently guided to the external air flow outlet 33.

  Further, in the circumferential direction of the outer peripheral wall portion 22, the formation length of the lower side chamfer portion 27 (the length of the outer wall surface 27 b of the outer peripheral wall portion 27) is equal to the formation length of the upper side chamfer portion 26 (outer peripheral wall portion). 26 is shorter than the length of the outer wall surface 26b of 26. As described above, the upper side chamfer 26 is advantageous in that the inner wall surface 26a is formed as an inclined surface in order to promote the rise of the internal gas. Will be smoother. On the other hand, the other lower side chamfer 27 does not contribute to gas rise when the inner wall surface is an inclined surface. Conversely, by reducing the size of the chamfer, The advantage of increased volume is obtained. That is, the wiring board 10 having a larger area can be arranged, and as a result, more elements can be arranged on the wiring board 10.

(Island heat radiation chamber 38B)
The island-shaped heat radiation chamber 38 </ b> B is a space surrounded by the isolation chamber 39, and is a space partitioned by the partition wall portion 4 and the bottom surface portion 21. Provided in the dense region of the local heat generating elements 8, the vent 3 is formed through the bottom surface 21 in the island-shaped heat radiation chamber 38B. Since the inside of the island-shaped heat radiation chamber 38B is relatively small, the ribs 22R and 4R are not formed, and are formed in a form connected to the partition wall portion 4 surrounding the island-shaped heat radiation chamber 38B in the outer isolation chamber 39. .

  Note that the above-described characteristic portion in the outer peripheral heat radiation chamber 38A may be applied to the island-shaped heat radiation chamber 38B if possible. However, since the island-shaped heat radiation chamber 38B is provided in the dense region of the local heat generating elements 8, there are many shape restrictions, and it is not always necessary to provide the feature of the outer peripheral heat radiation chamber 38A.

(Isolation room 39)
The isolation chamber 39 is provided as a remaining area of the heat dissipation chamber 38, and is provided as one space in the present embodiment. The outer peripheral heat radiation chamber 38 </ b> A is formed on one intermediate outer peripheral wall portion 25 side of the outer peripheral wall portion 22, and the space adjacent to the opposite intermediate outer peripheral wall portion 25 is a part of the isolation chamber 39. . No vent 3 is provided.

  As mentioned above, although one Embodiment of this invention was described, these are only illustrations to the last, and this invention is not limited to these, A various change is possible unless it deviates from the meaning of a claim. is there.

  In the above embodiment, the predetermined heat dissipation required element 8 and the predetermined outside air aversion element 9 are defined, but the heat dissipation required element 8 is equivalent to the various heat dissipation required elements 8 described above, or In addition, elements having exothermic properties can be included. On the other hand, the external air aversion element 9 can include elements that are equivalent to or more susceptible to the adverse effects of moisture than the humidity aversion element 9 described above. Furthermore, not only humidity but also other elements that are more susceptible to the adverse effect of the components contained in the outside air than the moisture aversion element 9 can be included.

  In the above embodiment, the internal space 30 is covered with the wiring board, and in particular, the isolation chamber 39 is thereby made a sealed space. However, the sealed space here is not a complete sealed space, and a slight gap or gap generated by assembly is allowed.

  In the above embodiment, the outer peripheral heat radiation chamber 38A is formed as a large space connected from the lower end side outer peripheral wall portion 24 to the intermediate outer peripheral wall portion 25, and from the intermediate outer peripheral wall portion 25 to the upper end side outer peripheral wall portion 23. Only the space connected from the outer peripheral wall part 24 to the intermediate outer peripheral wall part 25 may be used, or only the space connected from the intermediate outer peripheral wall part 25 to the upper end side outer peripheral wall part 23 may be used. Furthermore, a space extending along the lower end side outer peripheral wall portion 24 or a space extending along the intermediate outer peripheral wall portion 25 or a space extending along the upper end side outer peripheral wall portion 23 may be used. It may be a formed space. However, if there is at least a space adjacent to the intermediate outer peripheral wall portion 25, it is easy to form a gas flow such as intake, rise, and exhaust by forming the vent hole 3 in the intermediate outer peripheral wall portion 25.

  In addition, the said embodiment does not deny that the external air disgusting element 9 of the thermal radiation chamber 38 is included, and does not deny that the thermal radiation required element 8 is included in the isolation chamber 39. The elements 8 and 9 on the wiring board 10 and other elements are basically arranged with priority given to circuit design, and the partition wall 4 is designed in consideration of the element arrangement on the wiring board 10 designed. The heat radiating chamber 38 is formed to be a heat radiating path taking in as many elements 8 as possible.

DESCRIPTION OF SYMBOLS 1 Vehicle electronic device 2 Case 20 Outer wall part 21 Bottom face part 22 Outer peripheral wall part 23 Upper end side outer peripheral wall part 24 Lower end side outer peripheral wall part 25 Middle outer peripheral wall part 3 Ventilation hole 30 Internal space 39 Isolation room 38 Heat radiation room 4 Partition wall part 8 Heat radiation required element 9 Outside air aversion element (humidity aversion element)
10 Wiring board

Claims (9)

A wiring board on which a plurality of elements are mounted is accommodated in the case, and the internal space of the case communicates with a vent provided in the outer wall portion of the case and requires heat dissipation mounted on the wiring board. A heat dissipating chamber extending so as to include a predetermined heat dissipating element, and all the vents provided in the case and the heat dissipating chamber are not in communication with the wiring board. an isolation chamber which encloses the outside air aversion element predetermined liable outside air adversely affected by mounting the can is partitioned by the partition wall portion,
The vehicle-use characterized in that the heat dissipating element and the outside air aversion element are mounted on the same surface of the wiring board, and the heat dissipating chamber and the isolation chamber are arranged side by side along the surface . Electronic equipment.   The case has a bottom surface portion and an outer peripheral wall portion that rises from the outer peripheral side of the bottom surface portion and surrounds the internal space, and the wiring board is formed on the partition wall portion formed in the internal space. The vehicular electronic device according to claim 1, wherein the vehicular electronic device is arranged so as to cover the internal space.   The case has a predetermined vertical positional relationship when mounted on a vehicle, and the vent is formed in an external airflow inlet formed in a lower end side outer wall portion of the case and an upper end side outer wall portion of the case. The vehicle electronic device according to claim 1, further comprising an external airflow outlet.   4. The vehicle electronics according to claim 3, wherein the wall portion surrounding the heat radiating chamber is formed in a shape toward the outside air flow outlet without stopping a flow of gas that naturally rises as the temperature increases in the heat radiating chamber. apparatus.   The case includes a bottom surface portion and an outer peripheral wall portion that rises from an outer peripheral side of the bottom surface portion and surrounds the internal space. The wall portion that surrounds the heat radiating chamber includes a part of the bottom surface portion and the partition wall. 5. The vehicular electronic device according to claim 1, wherein the heat dissipating chamber is formed so as to extend along the outer peripheral wall portion. . Comprising the requirements of claim 4;
The heat radiating chamber forms a heat radiating path from the external airflow inlet formed in the outer peripheral wall portion on the lower end side of the case to the outer air outlet formed in the outer peripheral wall portion on the upper end side of the case, and The vehicular electronic device according to claim 5, wherein one intermediate outer peripheral wall portion connecting the lower end side outer peripheral wall portion to the upper end side outer peripheral wall portion is part of a wall portion surrounding the heat radiating chamber.   In the heat radiating chamber, at least an inner wall surface on the intermediate outer peripheral wall portion side of the partition wall portion facing above an opening provided on the outer peripheral wall portion on the lower end side of the outer airflow inlet is the intermediate outer wall. The vehicular electronic device according to claim 6, wherein the vehicular electronic device is formed as an inclined surface that rises and inclines toward the portion.   In the case, an upper corner portion connecting the intermediate outer peripheral wall portion and the outer peripheral wall portion on the upper end side is formed as an upper side chamfered portion, and an inner wall surface on the heat radiation chamber side of the upper side chamfered portion is formed on the upper end side. The vehicular electronic device according to claim 6, wherein the vehicular electronic device is formed as an inclined surface that rises and inclines toward an outer peripheral wall portion of the vehicle. In the case, a lower corner portion connecting the intermediate outer peripheral wall portion and the outer peripheral wall portion on the lower end side is formed as a lower side chamfered portion, and the formation length of the lower side chamfered portion in the circumferential direction of the outer peripheral wall portion The vehicle electronic device according to claim 8, wherein the length is shorter than a formation length of the upper side chamfered portion.