JP6683010B2 - Electronic device and filter device - Google Patents

Description

  The present invention relates to an electronic device including an electronic component, a housing, and a filter device, and a filter device.

  Conventionally, as described in Patent Document 1, a ventilation member fixed to an opening of a housing is known. The ventilation member has a support body fixed to the housing and a ventilation membrane fixed to the support body. The support has a through hole for allowing the accommodation space to ventilate with the external space. In the support, a plurality of through holes that are open to the gas permeable membrane side are formed so as to be one on the accommodation space side. The breathable film is fixed to the support so as to cover the through hole.

JP, 2009-29423, A

  By the way, a configuration in which the heat generating member is arranged in the accommodation space is conceivable. Due to the heat generated by the heat generating member, the temperature of the accommodation space becomes higher than the temperature of the external space. According to this, the atmospheric pressure of the accommodation space becomes higher than the atmospheric pressure of the external space. Therefore, the high temperature air flows from the accommodation space to the external space through the ventilation member. At this time, the high temperature air flows to the external space through the through hole and the ventilation film.

  In the above configuration, since all the through holes are one on the accommodation space side, the shortest distance between the heat generating member side opening of the through holes and the heat generating member is the same for all the through holes. Therefore, when the temperature of the storage space rises, air flows from the storage space side to the external space side in all the through holes. Therefore, it is difficult for the air in the external space, which has a lower temperature than the accommodation space, to flow into the accommodation space through the through hole. Therefore, the air in the accommodation space is unlikely to be cooled by the air in the external space. According to this, there is a possibility that the temperature of the accommodation space becomes high and the temperature of the heat generating member becomes high.

  The present invention has been made in view of such problems, and an object thereof is to provide an electronic device and a filter device that can suppress the temperature of the heat generating member from increasing.

  The present invention employs the following technical means in order to achieve the above object. Note that the reference numerals in parentheses show the correspondence with specific means in the following embodiments as one aspect, and do not limit the technical scope.

One of the present inventions is
A heat generating member (10),
A housing (20) in which the heat generating member is housed in the housing space (22) and the housing space is watertightly sealed;
A filter device (40) that is provided in the housing and that prevents the liquid in the external space (200) from entering the storage space and that allows ventilation between the storage space and the external space;
Equipped with
The filter device is provided with a filter case (44) having a plurality of ventilation paths for allowing the accommodation space to ventilate with the external space, and has a waterproof property and a ventilation property, and is arranged in the filter case to block all the ventilation paths. A filter (42),
The filter case has a main body part (48) provided in the housing and in which the filter is arranged, and a lid part (50) fixed to the main body part and covering the filter,
As the ventilation path, both the first path (60a, 60d) and the second path (60b, 60c) formed so as not to intersect the first path are formed in each of the main body section and the lid section,
The opening on the heat generating member side in the first path and the opening on the heat generating member side in the second path are located on the side opposite to the direction of gravity with respect to the heat generating member,
The opening on the heat generating member side in the first path has a shortest distance to the heat generating member compared to the opening on the heat generating member side in the second path ,
The main body is
A first cylindrical portion (48a) having a cylindrical shape and forming a first path by the inner peripheral surface;
A second cylindrical portion (48d) having a cylindrical shape surrounding the outer peripheral surface of the first cylindrical portion and forming a second path by the inner peripheral surface;
Have

  In the above structure, the opening on the heat generating member side in the first path has the shortest distance to the heat generating member compared to the opening on the heat generating member side in the second path. According to this, when the temperature of the heat generating member rises, the air around the heat generating member in the accommodation space passes through the first route more easily than the second route when flowing to the external space. That is, the air having a relatively high temperature passes through the first path more easily than the second path.

  When air flows from the accommodation space to the external space, the atmospheric pressure around the heat generating member in the accommodation space decreases. However, in the first path, since air flows from the accommodation space side to the external space side, it is difficult for air to flow from the external space to the accommodation space even when the atmospheric pressure of the accommodation space drops. On the other hand, in the second path, air is less likely to flow from the accommodation space side to the external space side than in the first path. Therefore, the air pressure in the accommodation space is lowered, so that the air easily flows from the external space side to the accommodation space side in the second path. That is, the air having a relatively low temperature in the external space flows through the second path to the periphery of the heat generating member having a low atmospheric pressure in the accommodation space.

  According to the above, air having a high temperature can be flowed from the periphery of the heat generating member to the external space, and air having a low temperature can be flowed from the external space to the periphery of the heat generating member. Therefore, it is possible to prevent the heat generating member from reaching a high temperature.

One of the other inventions is
The housing (20) for housing the heat generating member (10) in the watertightly sealed housing space (22) suppresses the liquid in the external space (200) from entering the housing space, and the housing space and the outside. A filter device that enables ventilation with a space,
A filter case (44) having a plurality of ventilation paths for allowing the accommodation space to ventilate with the external space;
A filter (42) that is waterproof and breathable, is placed in the filter case, and blocks all ventilation paths.
The filter case has a main body part (48) provided in the housing and in which the filter is arranged, and a lid part (50) fixed to the main body part and covering the filter,
As the ventilation path, both the first path (60a, 60d) and the second path (60b, 60c) formed so as not to intersect the first path are formed in each of the main body section and the lid section,
The opening on the heat generating member side in the first path and the opening on the heat generating member side in the second path are located on the side opposite to the direction of gravity with respect to the heat generating member,
The opening on the heat generating member side in the first path has a shortest distance to the heat generating member compared to the opening on the heat generating member side in the second path ,
The main body is
A first cylindrical portion (48a) having a cylindrical shape and forming a first path by the inner peripheral surface;
A second cylindrical portion (48d) having a cylindrical shape surrounding the outer peripheral surface of the first cylindrical portion and forming a second path by the inner peripheral surface;
Have

  With the above structure, it is possible to achieve the same effects as the electronic device described above.

It is a sectional view showing a schematic structure of an electronic device concerning a 1st embodiment. It is a perspective view showing a schematic structure of a filter device. It is sectional drawing which follows the III-III line of FIG. It is a side view which shows schematic structure of a filter apparatus. It is a top view which shows the structure of a filter. It is a top view which shows schematic structure of a main-body part. FIG. 9 is a cross-sectional view showing a schematic configuration of a filter device in the electronic device according to the second embodiment. It is a perspective view showing a schematic structure of a main part.

  A description will be given with reference to the drawings. In addition, in a plurality of embodiments, common or related elements are given the same reference numerals. Further, the thickness direction of the filter is indicated as the Z direction, the specific direction orthogonal to the Z direction is indicated as the X direction, and the Z direction and the direction orthogonal to the X direction are indicated as the Y direction. A plane defined by the X direction and the Y direction is referred to as an XY plane. A shape along the XY plane is shown as a planar shape.

(First embodiment)
First, a schematic configuration of the electronic device 100 will be described with reference to FIGS. 1 to 6.

  As shown in FIG. 1, the electronic device 100 includes a circuit board 10, a housing 20, and a filter device 40. In the present embodiment, the electronic device 100 is arranged in the vehicle. Specifically, the electronic device 100 is arranged in the engine compartment of the vehicle or in the passenger compartment. The electronic device 100 is an ECU for a vehicle. The electronic device 100 can also be referred to as an electronic control device.

  The circuit board 10 includes a board 12, a connector 13 for electrical connection with the outside of the electronic device 100, and an electronic component 14 mounted on the board 12. The substrate 12 has a substantially flat plate shape whose thickness direction extends along the Z direction. The substrate 12 has one surface 12a and a back surface 12b. The connector 13 electrically relays the external device and the circuit board 10. The electronic components 14 are arranged on both sides of the one surface 12a and the back surface 12b. However, it is also possible to adopt an example in which the electronic component 14 is arranged only on one surface of the substrate 12. The circuit board 10 has, as the electronic component 14, a heat-generating component that generates a relatively larger amount of heat than other electronic components 14. As the heat generating component, for example, a MOS or a diode can be adopted. The temperature of the heat generating component rises up to about 120 ° C. by driving, for example.

  The housing 20 accommodates the circuit board 10 in the accommodation space 22. The housing 20 is formed using, for example, a resin material or a metal material. The housing 20 has a first case 24 and a second case 26. The first case 24 and the second case 26 are in the shape of a box with one surface open. The first case 24 and the second case 26 are arranged so as to close each other's openings. Hereinafter, the opening of the first case 24 that is closed by the second case 26 is referred to as an opening 24a.

  The first case 24 has a bottom portion 28 and a side wall portion 30. The bottom portion 28 has a substantially flat plate shape whose thickness direction extends along the Z direction. The bottom portion 28 has a front surface 28a defining the accommodation space 22 and a back surface 28b opposite to the front surface 28a. The front surface 28a and the back surface 28b are planes orthogonal to the Z direction. The side wall portion 30 extends in the Z direction from the outer peripheral portion of the bottom portion 28 on the XY plane. An end portion of the side wall portion 30 opposite to the bottom portion 28 forms an opening 24a.

  An opening 30a for the connector 13 is formed in one side wall 30. The opening 30a is formed so that the connector 13 is exposed to the external space 200. The connector 13 is partially exposed to the external space 200 from the portion connected to the substrate 12 through the opening 30a. In the present embodiment, the opening 30a communicates with the opening 24a. That is, the opening 30a is open to the second case 26 side in the Z direction at a location not shown.

  The first case 24 and the second case 26 are fixed to each other by screw fastening or the like. A sealing material (not shown) is arranged between the outer peripheral edge of the first case 24 and the opposing peripheral edge of the second case 26. The sealing material is also disposed between the side wall portion 30 forming the opening 30 a and the facing portion of the connector 13. Further, the sealing material is also arranged between the second case 26 and the facing portion of the connector 13. As described above, the accommodation space 22 is watertightly sealed. In other words, the housing 20 has a waterproof structure.

  The circuit board 10 is fixed to at least one of the first case 24 and the second case 26 by screw fastening or the like. The housing 20 is not limited to the shape having the first case 24 and the second case 26. The housing 20 may be at least the one that houses the circuit board 10.

  The front surface 28a faces the one surface 12a in the Z direction. In the present embodiment, the direction from the surface 28a to the circuit board 10 in the Z direction is substantially the same as the gravity direction. That is, the circuit board 10 is arranged on the gravity direction side of the surface 28a.

  A communication hole 32 that communicates the accommodation space 22 and the external space 200 is formed in the first case 24. The external space 200 is a space outside the housing 20 and is a space around the housing 20. In other words, the external space 200 is a space in which the electronic device 100 is arranged. The back surface 28b is in contact with the external space 200. The communication hole 32 is a through hole that penetrates the bottom portion 28 from the front surface 28a to the back surface 28b. A planar shape of the communication hole 32 is a substantially perfect circle. It is also possible to adopt an example in which the planar shape of the communication hole 32 is a polygonal shape.

  When the electronic device 100 is arranged in the engine compartment, the temperature of the accommodation space 22 is, for example, 80 ° C to 90 ° C. When the electronic device 100 is arranged in the vehicle compartment, the temperature of the accommodation space 22 is, for example, 50 ° C. to 60 ° C.

  The filter device 40 suppresses the liquid from entering the accommodation space 22 from the external space 200 through the communication hole 32. As this liquid, rain water, water used for car washing, water rolled up while the vehicle is running, and the like are assumed. The filter device 40 prevents liquid from entering the accommodation space 22 and coming into contact with the circuit board 10. Further, the filter device 40 enables ventilation between the accommodation space 22 and the external space 200 via the communication hole 32. The filter device 40 can also be called a ventilation member or a waterproof member.

  As shown in FIGS. 2 to 4, the filter device 40 includes a filter 42, a filter case 44, and a seal ring 46. Note that, in FIG. 2, the housing 20, the filter 42, and the filter case 44 are shown separated in the Z direction for the sake of convenience in order to clarify the structure of the filter device 40. When viewed in the Z direction, the centers of the communication hole 32, the filter 42, the filter case 44, and the seal ring 46 are substantially coincident with each other. In FIG. 2, a line passing through the centers of the communication hole 32, the filter 42, the filter case 44, and the seal ring 46 is shown by a broken line.

  The filter 42 is waterproof and breathable, and closes the communication hole 32 together with the filter case 44. That is, the filter 42 not only allows the gas to pass therethrough, but also suppresses the passage of the liquid. Further, the filter 42 has water repellency and oil repellency. That is, the filter 42 is subjected to a water repellent treatment and an oil repellent treatment. Therefore, the filter 42 can also be called a water repellent filter or an oil repellent filter. The filter 42 can also be referred to as a gas permeable membrane.

  As shown in FIG. 5, the filter 42 is formed with a plurality of holes. As the filter 42, for example, a porous film formed using fluororesin or polyolefin can be used. The diameter r of the holes in the filter 42 is, for example, 0.01 to 10 μm. The gas can pass through the pores of the filter 42. On the other hand, the liquid does not pass through the holes of the filter 42.

  The filter 42 is arranged in the filter case 44. The filter case 44 is arranged in the housing 20. The filter case 44 is formed with a plurality of ventilation paths for allowing the accommodation space 22 to ventilate with the external space 200. All the ventilation paths formed in the filter case 44 are closed by the filter 42. The filter case 44 is made of, for example, a resin material. At least a part of the filter case 44 is arranged in the space surrounded by the communication hole 32.

  In this embodiment, the filter case 44 is formed by injection molding. In detail, the molten resin is poured into the mold. The filter case 44 has a main body 48 and a lid 50.

  The heat generating component mounted on the one surface 12a or the back surface 12b is arranged on the gravity direction side of the filter case 44. That is, in the Z-direction projection view, the filter case 44 overlaps the heat generating component mounted on the one surface 12a or the back surface 12b.

  As shown in FIG. 3, the main body 48 is fixed to the housing 20. More specifically, the main body portion 48 is fixed near the portion of the bottom portion 28 where the communication hole 32 is formed. The filter 42 is arranged in the main body 48. As shown in FIGS. 2 to 4 and 6, the main body portion 48 has an inner tubular portion 48a, an outer tubular portion 48b, and a rib 48c. In order to clarify the structure of the main body 48, FIG. 6 shows the main body 48 in a state in which the lid 50 and the filter 42 are not arranged. Further, in FIG. 6, the inner hole 60a and the outer hole 60b are hatched to clarify the planar shapes of the inner hole 60a and the outer hole 60b.

  The inner tubular portion 48a forms the inner hole 60a as a ventilation path. The inner hole 60a is a ventilation path for flowing air from the accommodation space 22 to the external space 200. The inner cylindrical portion 48a has a substantially cylindrical shape extending along the Z direction. An inner hole 60a is formed by the inner peripheral surface of the inner cylindrical portion 48a. The inner peripheral surface and the outer peripheral surface of the inner tubular portion 48a are substantially circular in plan view. The inner tubular portion 48a corresponds to the first tubular portion recited in the claims.

  The inner cylindrical portion 48a is inserted through the communication hole 32. Part of the inner tubular portion 48a is arranged in the space surrounded by the communication hole 32. In a projection view in the Z direction, the outer peripheral surface of the inner tubular portion 48 a has a smaller diameter than the communication hole 32 and is surrounded by the communication hole 32. Further, in the Z-direction projected view, the centers of the inner peripheral surface and the outer peripheral surface of the inner tubular portion 48a are substantially coincident with the center of the communication hole 32.

  In the Z direction, one opening in the inner tubular portion 48a is located on the accommodation space 22 side with respect to the bottom portion 28. On the other hand, in the Z direction, the other opening of the inner tubular portion 48a is located closer to the external space 200 than the bottom portion 28 is.

  The opening on the accommodation space 22 side of the inner tubular portion 48a is provided on the side of the heat generating component of the circuit board 10 opposite to the direction of gravity. That is, the opening of the inner hole 60a on the heat generating component side is located on the side opposite to the gravity direction with respect to the heat generating component. In other words, the electronic device 100 is assembled in the vehicle so that the opening on the heat generating component side of the inner hole 60a is located on the side opposite to the gravity direction with respect to the heat generating component.

  The outer tubular portion 48b is arranged so as to surround the inner tubular portion 48a when viewed in the Z direction. As shown in FIGS. 2, 3, and 6, the outer cylindrical portion 48b has a cylindrical portion 48d, a disk portion 48e, and a protruding portion 48f.

  The cylindrical portion 48d forms the outer hole 60b as a ventilation path. The outer hole 60b is a ventilation path for flowing air from the external space 200 to the accommodation space 22. The cylindrical portion 48d has a substantially cylindrical shape extending along the Z direction. The cylindrical portion 48d surrounds the outer peripheral surface of the inner cylindrical portion 48a. An outer hole 60b is formed by the inner peripheral surface of the cylindrical portion 48d and the outer peripheral surface of the inner cylindrical portion 48a. The cylindrical portion 48d corresponds to the second cylindrical portion recited in the claims.

  The planar shapes of the inner peripheral surface and the outer peripheral surface of the cylindrical portion 48d are substantially circular. The cylindrical portion 48d is inserted through the communication hole 32. A part of the cylindrical portion 48d is arranged in the space surrounded by the communication hole 32. The outer peripheral surface of the cylindrical portion 48d substantially coincides with the communication hole 32 in the Z-direction projected view. In the Z-direction projected view, the centers of the inner peripheral surface and the outer peripheral surface of the cylindrical portion 48d are substantially coincident with the center of the communication hole 32.

  In the Z direction, one end of the cylindrical portion 48d is located on the accommodation space 22 side with respect to the bottom portion 28. On the other hand, in the Z direction, the other end of the cylindrical portion 48d is located closer to the external space 200 than the bottom portion 28 is.

  The opening of the cylindrical portion 48d on the accommodation space 22 side is provided on the side of the heat generating component of the circuit board 10 opposite to the direction of gravity. That is, the opening on the heat generating component side of the outer hole 60b is located on the side opposite to the gravity direction with respect to the heat generating component. In other words, the electronic device 100 is assembled in the vehicle so that the opening on the heat generating component side of the outer hole 60b is located on the side opposite to the gravity direction with respect to the heat generating component.

  Both the outer hole 60b and the inner hole 60a extend in the Z direction. The outer hole 60b does not intersect with the inner hole 60a. In other words, the outer hole 60b does not communicate with the inner hole 60a.

  The end portion of the inner tubular portion 48a on the accommodation space 22 side has a shorter minimum distance to the heat generating component or the circuit board 10 than the end portion of the cylindrical portion 48d on the accommodation space 22 side. In other words, the opening of the inner hole 60a on the heat generating component side has a shorter shortest distance to the heat generating component or the circuit board 10 than the opening of the outer hole 60b on the heat generating component side. Therefore, the opening on the heat generating component side of the inner hole 60a is located on the gravity direction side with respect to the opening on the heat generating component side of the outer hole 60b.

  The filter 42 is arranged at the ends of the inner cylindrical portion 48a, the rib 48c, and the cylindrical portion 48d on the external space 200 side. The disk portion 48e extends from the end of the cylindrical portion 48d on the side of the external space 200 in the direction orthogonal to the Z direction and in the direction from the inner circumference to the outer circumference of the cylindrical portion 48d. As shown in FIG. 6, the planar shape of the disk portion 48e is a substantially annular shape. The planar shapes of the inner peripheral edge and the outer peripheral edge of the disk portion 48e are substantially circular.

  The disk portion 48e is arranged on the external space 200 side with respect to the bottom portion 28 in the Z direction. The connecting portion between the disc portion 48e and the cylindrical portion 48d is provided at substantially the same position as the end portion of the inner tubular portion 48a on the external space 200 side in the Z direction.

  The rib 48c connects the inner cylindrical portion 48a and the cylindrical portion 48d. That is, the rib 48c connects the inner tubular portion 48a and the outer tubular portion 48b. The rib 48c allows the inner cylindrical portion 48a to be arranged at a position apart from the cylindrical portion 48d. The rib 48c extends from a part of the connecting portion between the disc portion 48e and the cylindrical portion 48d toward the outer peripheral surface of the inner tubular portion 48a. As a result, the rib 48c forms a part of the opening of the outer hole 60b. The rib 48c is formed at substantially the same position as the disk portion 48e in the Z direction. The length of the rib 48c in the Z direction is shorter than the length of the cylindrical portion 48d in the Z direction. In the present embodiment, the filter case 44 has three ribs 48c. When viewed in the Z direction, the three ribs 48c surround the inner tubular portion 48a.

  In the present embodiment, the number of filters 42 in the filter device 40 is one. One filter 42 is in contact with the connecting portion of the disk portion 48e and the cylindrical portion 48d, and the end portion of the inner tubular portion 48a on the side of the external space 200, and the opening of the inner hole 60a and the outer hole 60b on the external space 200 side. Are arranged so as to block both. The filter 42 is fixed to the filter case 44 by welding, an adhesive material or the like.

  The outer peripheral end of the disk portion 48e is made larger than the filter 42 and surrounds the filter 42 when viewed in the Z direction. Therefore, the surface of the disk portion 48e opposite to the bottom portion 28 has a portion where the filter 42 is arranged and a portion where the filter 42 is not arranged.

  A groove 48g that suppresses the water in the external space 200 from flowing to the filter 42 is formed in the disk portion 48e. The groove 48g is recessed in the Z direction from the surface of the disk portion 48e opposite to the bottom portion 28. That is, the groove 48g is recessed in the direction of gravity from the surface of the disk portion 48e opposite to the bottom portion 28. The planar shape of the groove 48g is a substantially annular shape in which the inner peripheral edge and the outer peripheral edge are substantially circular. When projected in the Z direction, the groove 48g surrounds the portion where the filter 42 is arranged.

  The surface of the disk portion 48e on the bottom portion 28 side holds the seal ring 46 together with the back surface 28b. That is, the disk portion 48e is arranged on the side opposite to the back surface 28b with respect to the seal ring 46.

  The protrusion 48 f is provided to fix the main body 48 to the bottom 28. The protrusion 48f extends from a part of the outer peripheral surface of the cylindrical portion 48d in a direction orthogonal to the Z direction and in a direction from the inner periphery to the outer periphery of the cylindrical portion 48d.

  The main body 48 has three protrusions 48f. When viewed in the Z direction, the communication hole 32 is surrounded by the three protrusions 48f. The surface of the protrusion 48f on the bottom 28 side is in contact with the surface 28a. In the Z direction, the protrusion 48f holds the bottom portion 28 and the seal ring 46 together with the disc portion 48e.

  Further, a cutout 48h is formed in the cylindrical portion 48d at a location different from the location where the protrusion 48f is provided. When disposing the main body 48 in the housing 20, the inner cylinder 48 a and the cylinder 48 d are inserted into the communication holes 32. At this time, since the cutout 48h is formed, the cylindrical portion 48d can be made smaller. After the main body portion 48 is arranged in the housing 20, the cylindrical portion 48d returns to the size before being inserted into the communication hole 32. As described above, the main body 48 can be arranged in the housing 20.

  The lid portion 50 forms a ventilation path while covering the filter 42. The lid 50 can also be called a cover or a cap. The lid 50 is fixed to the body 48. The lid 50 is arranged on the side opposite to the housing space 22 with respect to the main body 48 in the Z direction. That is, the lid 50 and the body 48 are arranged side by side in the Z direction. The entire lid part 50 is arranged on the external space 200 side with respect to the bottom part 28.

  The lid portion 50 has a cylindrical portion 50a, a first ceiling portion 50b, a connecting portion 50c, a second ceiling portion 50d, and a pillar portion 50e. The cylindrical portion 50a, the first ceiling portion 50b, the connecting portion 50c, the second ceiling portion 50d, and the pillar portion 50e are connected to each other.

  The cylindrical portion 50a has a substantially cylindrical shape extending in the Z direction, and the inner peripheral surface and the outer peripheral surface thereof have a substantially perfect circular planar shape. The cylindrical portion 50a is arranged on the opposite side of the filter 42 from the inner cylindrical portion 48a. The end of the cylindrical portion 50a on the filter 42 side is in contact with the filter 42. The inner peripheral surface of the cylindrical portion 50a substantially coincides with the inner peripheral surface of the inner cylindrical portion 48a when viewed in the Z direction. As described above, the space surrounded by the cylindrical portion 50a communicates with the inner hole 60a via the filter 42. In the Z-direction projection view, the outer peripheral surface of the cylindrical portion 50a is substantially coincident with the outer peripheral surface of the inner cylindrical portion 48a.

  The first ceiling portion 50b extends from the end of the cylindrical portion 50a on the side of the external space 200 in the direction orthogonal to the Z direction and in the direction from the inner periphery to the outer periphery of the cylindrical portion 50a. In the Z direction, the first ceiling portion 50b faces the filter 42 and the disk portion 48e with a predetermined distance. When projected in the Z direction, part of the first ceiling portion 50b overlaps part of the filter 42. The planar shape of the first ceiling portion 50b is a substantially annular shape in which the planar shapes of the inner peripheral edge and the outer peripheral edge are substantially perfect circles. When viewed in the Z direction, the outer peripheral edge of the disk portion 48e is surrounded by the outer peripheral edge of the first ceiling portion 50b.

  The connecting portion 50c is for connecting the lid portion 50 to the main body portion 48. The connection portion 50c extends from the outer peripheral end of the first ceiling portion 50b on the XY plane toward the bottom portion 28 side in the Z direction. The lid part 50 has three connection parts 50c. At the outer peripheral edge of the first ceiling portion 50b, a portion where the connecting portion 50c extends and a portion where the connecting portion 50c does not extend are formed. When viewed in the Z direction, the three connecting portions 50c surround the disk portion 48e. The side surface of the connecting portion 50c is in contact with the surface of the disk portion 48e opposite to the cylindrical portion 48d. In the Z direction, the end portion of the connecting portion 50c on the bottom portion 28 side is located closer to the bottom portion 28 side than the surface of the disc portion 48e on the bottom portion 28 side.

  A claw is formed at the end of each connection portion 50c on the bottom 28 side. The claw extends from the end of the connecting portion 50c on the bottom 28 side in the direction orthogonal to the Z direction toward the inner hole 60a. In other words, the claws of the connection portion 50c extend from the end portion on the bottom portion 28 side in the direction orthogonal to the Z direction and toward the seal ring 46. The connecting portion 50c is not in contact with the seal ring 46. The claw of the connecting portion 50c is in contact with the surface of the disk portion 48e on the bottom portion 28 side. The lid 50 is fixed to the main body 48 by the claws of the connecting portion 50c.

  Hereinafter, the space surrounded by the cylindrical portion 50a, the first ceiling portion 50b, the connecting portion 50c, and the disc portion 48e is referred to as an outer path 60c. The outer path 60c is a ventilation path for flowing air from the external space 200 to the accommodation space 22. The opening of the outer path 60c on the accommodation space 22 side is closed by the filter 42. The outer path 60c communicates with the outer hole 60b via the filter 42. Further, the outer path 60c communicates with the external space 200. The opening of the outer path 60c on the external space 200 side is formed by a portion of the outer peripheral end of the first ceiling portion 50b where the connecting portion 50c does not extend. The outer hole 60b and the outer path 60c correspond to the second path described in the claims.

  The second ceiling portion 50d is arranged on the side opposite to the filter 42 with respect to the cylindrical portion 50a and the first ceiling portion 50b. The second ceiling portion 50d faces the cylindrical portion 50a and the first ceiling portion 50b with a predetermined distance in the Z direction. The second ceiling portion 50d has a substantially flat plate shape whose thickness direction extends along the Z direction. The planar shape of the second ceiling portion 50d is a substantially perfect circle. When projected in the Z direction, the center of the second ceiling portion 50d substantially coincides with the center of the cylindrical portion 50a. When projected in the Z direction, a part of the second ceiling portion 50d overlaps the entire cylindrical portion 50a. That is, when viewed in the Z direction, the second ceiling portion 50d surrounds the outer peripheral surface of the cylindrical portion 50a.

  The pillar portion 50e connects the first ceiling portion 50b and the second ceiling portion 50d. The column portion 50e extends in the Z direction. The pillar portion 50e extends in the Z direction from the outer peripheral end of the second ceiling portion 50d on the XY plane to the first ceiling portion 50b. The lid 50 has three pillars 50e. At the outer peripheral end of the second ceiling portion 50d, a portion where the connecting portion 50c extends and a portion where the pillar portion 50e does not extend are formed. In the Z-direction projected view, the three column portions 50e surround the cylindrical portion 50a.

  Hereinafter, the space surrounded by the cylindrical portion 50a, the first ceiling portion 50b, the second ceiling portion 50d, and the column portion 50e is referred to as an inner path 60d. The inner path 60d is a ventilation path for flowing air from the accommodation space 22 to the external space 200. The opening on the accommodation space 22 side in the inner path 60d is closed by the filter 42. The inner path 60d communicates with the inner hole 60a via the filter 42. The inner path 60d communicates with the external space 200. The opening of the inner path 60d on the side of the external space 200 is formed by a portion of the outer peripheral end of the second ceiling portion 50d where the pillar portion 50e is not extended.

  The inner path 60d does not intersect with the outer hole 60b and the outer path 60c. In other words, the inner path 60d does not intersect the outer hole 60b and the outer path 60c. In other words, the inner path 60d does not communicate with the outer hole 60b and the outer path 60c. Similarly, the outer path 60c does not intersect the inner hole 60a and the inner path 60d. The inner hole 60a and the inner path 60d correspond to the first path described in the claims.

  The connecting portion between the cylindrical portion 50a and the first ceiling portion 50b is located closer to the second ceiling portion 50d than the other portions of the first ceiling portion 50b in the Z direction. In other words, the peripheral portion of the opening of the cylindrical portion 50a opposite to the filter 42 is located closer to the second ceiling portion 50d than the first ceiling portion 50b in the Z direction. According to this, it is possible to suppress the water that has entered the inner path 60d from the external space 200 from entering the space surrounded by the cylindrical portion 50a, and eventually suppress the flow to the filter 42.

  The seal ring 46 prevents the liquid from passing between the filter case 44 and the bottom portion 28. That is, the seal ring 46 is provided for waterproofing. The seal ring 46 is made of, for example, a rubber material. The seal ring 46 can also be called an O ring.

  The seal ring 46 has a through hole extending in the Z direction. The inner peripheral end of the seal ring 46 substantially coincides with the inner peripheral end of the communication hole 32 in the Z-direction projected view. The seal ring 46 is arranged between the filter case 44 and the housing 20, and is in contact with the filter case 44 and the housing 20. Specifically, the seal ring 46 is arranged between the back surface 28b and the disk portion 48e, and is in contact with the back surface 28b and the disk portion 48e.

  After being assembled in the housing 20, the seal ring 46 is deformed as compared with before being assembled in the housing 20. More specifically, the seal ring 46 is deformed so that the width in the Z direction becomes smaller after being assembled to the housing 20. As a result, the seal ring 46 suppresses formation of a gap between the back surface 28b and the disc portion 48e.

  Next, the flow of air flowing through the ventilation path of the filter case 44 will be described with reference to FIG. The white arrows in FIG. 3 indicate the flow of air.

  When the circuit board 10 starts driving, the temperature of the circuit board 10 rises. As a result, the temperature around the circuit board 10 in the accommodation space 22 rises. Therefore, the temperature around the circuit board 10 in the accommodation space 22 becomes higher than the temperature of the external space 200.

  In the present embodiment in which the circuit board 10 has heat-generating components, the temperature around the heat-generating components is particularly high. When the temperature rises, the atmospheric pressure rises. Air flows from a space with high atmospheric pressure toward a space with low atmospheric pressure.

  Also, the density of air decreases as the temperature rises. Low density air is lighter than high density air. Therefore, the air whose temperature rises and becomes lighter due to the driving of the circuit board 10 advances to the side opposite to the direction of gravity. According to the above, by driving the circuit board 10, the air around the heat-generating components arranged on the gravity direction side of the filter device 40 advances toward the filter device 40.

  On the other hand, the opening of the inner hole 60a on the heat generating component side has a shorter shortest distance to the heat generating component than the opening of the outer hole 60b on the heat generating component side. Therefore, the air whose temperature has risen due to the heat-generating component flows more easily into the inner hole 60a than the outer hole 60b. The air whose temperature has risen due to the heat-generating components travels through the inner hole 60a in the direction opposite to the gravity direction. Then, the high temperature air flows from the inner hole 60a to the outer space 200 through the filter 42 and the inner path 60d.

  By the way, as the air around the heat-generating component flows into the external space 200, the atmospheric pressure of the air around the heat-generating component decreases. Therefore, the air in the external space 200 flows into the accommodation space 22 through the ventilation path of the filter case 44. At this time, in the inner hole 60a and the inner path 60d, the air flows toward the external space 200, so that the air does not easily flow from the external space 200 side to the accommodation space 22 side. On the other hand, the outer hole 60b has an opening on the heat generating component side farther from the heat generating component than the inner hole 60a. Therefore, in the outer hole 60b and the outer path 60c, it is more difficult for air to flow from the accommodation space 22 to the outer space 200 than in the inner hole 60a and the inner path 60d.

  According to this, the atmospheric pressure of the air around the heat-generating component decreases, so that the air in the external space 200 flows into the accommodation space 22 through the outer path 60c, the filter 42, and the outer hole 60b. Part of the air that has flowed into the accommodation space 22 through the outer hole 60b proceeds in a direction other than the direction of gravity. However, since the air pressure around the heat-generating component is low, the air traveling in a direction other than the direction of gravity also travels to the periphery of the heat-generating component. As described above, the air having a relatively low temperature travels around the heat generating component.

  According to the above, the air whose temperature is raised by the heat generating component flows from the accommodation space 22 to the external space 200, and the air having a relatively low temperature flows from the external space 200 to the periphery of the heat generating component. These air flows can also be called convection. This convection cools the heat-generating component.

  Next, effects of the electronic device 100 described above will be described.

  In the present embodiment, as described above, high temperature air can flow from the periphery of the circuit board 10 to the external space 200, and low temperature air can flow from the external space 200 to the periphery of the circuit board 10. it can. According to this, it is possible to suppress the temperature of the circuit board 10 from becoming high.

  As described above, the air whose temperature rises and becomes lighter due to the driving of the circuit board 10 advances to the side opposite to the direction of gravity. On the other hand, the opening on the heat generating component side of the inner hole 60a is provided on the side opposite to the gravity direction with respect to the heat generating component. According to this, the high temperature air around the heat generating component easily flows into the external space 200 through the inner hole 60a and the inner path 60d.

  Since air easily flows from the periphery of the heat-generating component to the filter device 40, the atmospheric pressure of the air around the heat-generating component is likely to drop. Therefore, the air in the external space 200 easily flows around the heat generating component through the outer path 60c and the outer hole 60b. According to the above, it is easy for the air having a high temperature to flow from the periphery of the heat generating component to the external space 200, and the air having a low temperature to flow from the external space 200 to the periphery of the heat generating component. Therefore, it is possible to effectively suppress an increase in the temperature of the heat generating component.

  By the way, a configuration in which the filter device 40 has a plurality of filters 42 and each filter 42 closes one ventilation path is conceivable. In contrast to this configuration, in the present embodiment, the filter device 40 has one filter 42 that closes all the ventilation paths formed in the filter case 44. According to this, the process of disposing the filter 42 in the filter case 44 can be simplified.

  When corners are formed in the mold for molding the filter case 44, stress is likely to concentrate on the corners when the molten resin is poured into the mold. On the other hand, in the present embodiment, both the inner cylindrical portion 48a forming the inner hole 60a and the cylindrical portion 48d forming the outer hole 60b in the main body portion 48 have a substantially cylindrical shape. According to this, compared to the configuration in which the planar shape of the inner peripheral surface and the outer peripheral surface of the portion forming the inner hole 60a and the outer hole 60b in the main body 48 is polygonal, the corners are formed in the mold. Can be suppressed. Therefore, in the mold for molding the filter case 44, it is possible to suppress the concentration of stress on a specific portion and to suppress the deterioration of the mold.

(Second embodiment)
In the present embodiment, description of parts common to those of the electronic device 100 shown in the first embodiment will be omitted.

  In the present embodiment, as shown in FIGS. 7 and 8, the filter case 44 is formed of the same member as the housing 20. Specifically, the main body 48 is formed of the same member as the first case 24. The main body 48 and the first case 24 are formed of a resin material. The lid 50 is formed of a member different from the body 48 and the first case 24.

  The outer tubular portion 48b of the filter case 44 has a substantially cylindrical shape extending from the bottom portion 28 to the accommodation space 22 side in the Z direction. A portion where the filter 42 is arranged, which is a connecting portion between the outer tubular portion 48b and the bottom portion 28, is located on the side opposite to the gravity direction with respect to the back surface 28b. As a result, it is possible to prevent water that has entered the outer path 60 c from the external space 200 from flowing to the filter 42.

  Note that the communication hole 32 shown in the first embodiment is not formed in the bottom portion 28 of the present embodiment. Further, in the present embodiment, the filter device 40 does not have the seal ring 46.

  The connection portion 50c is connected to the bottom portion 28. For example, the bottom portion 28 has a structure that is snap-fit connected to the connecting portion 50c. Further, it is also possible to adopt a configuration in which the connecting portion 50c is fixed to the bottom portion 28 via an adhesive material.

  In the present embodiment, the step of disposing the main body portion 48 in the first case 24 can be omitted in contrast to the configuration in which the main body portion 48 is a separate member from the first case 24. Further, in the present embodiment, the seal ring 46 provided between the filter case 44 and the housing 20 can be omitted. Therefore, the cost of the seal ring 46 can be suppressed, and the step of disposing the seal ring 46 can be simplified.

  Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention.

  In the above-described embodiment, the main body 48 has the example including the inner tubular portion 48a, the outer tubular portion 48b, and the rib 48c, but the present invention is not limited to this. Further, in the above-described embodiment, the lid part 50 has the cylindrical part 50a, the first ceiling part 50b, the connecting part 50c, the second ceiling part 50d, and the pillar part 50e. It is not limited.

  In the above embodiment, the length of the rib 48c in the Z direction is shorter than the length of the cylindrical portion 48d in the Z direction, but the length is not limited to this. The length of the rib 48c in the Z direction may be substantially equal to the length of the cylindrical portion 48d in the Z direction. In this example, the outer hole 60b is divided by the rib 48c, and three outer holes 60b are formed in the main body 48.

  In the above-described embodiment, the example in which the circuit board 10 having the board 12 and the electronic component 14 is arranged in the accommodation space 22 has been shown, but the invention is not limited to this. It is sufficient that at least a heat-generating member that generates heat when energized is disposed in the accommodation space 22. It is also possible to adopt an example in which only electronic components such as sensors are arranged in the housing 20. In this example, the opening of the inner hole 60a on the electronic component side has a shorter shortest distance to the electronic component than the opening of the outer hole 60b on the electronic component side. In this example, the electronic component corresponds to the heat generating member described in the claims.

  It is also possible to adopt an example in which a plurality of heat generating members are arranged in the accommodation space 22. In this example, the opening of the inner hole 60a on the accommodation space 22 side has a shorter shortest distance than the opening of the outer hole 60b on the accommodation space 22 side with respect to the heat generating member closest to the filter device 40. Has been done.

DESCRIPTION OF SYMBOLS 10 ... Circuit board, 12 ... Board, 12a ... One side, 12b ... Back side, 13 ... Connector, 14 ... Electronic component, 20 ... Housing, 22 ... Housing space, 24 ... First case, 26 ... Second case, 28 ... Bottom portion, 28a ... Front surface, 28b ... Back surface, 30 ... Side wall portion, 32 ... Communication hole, 40 ... Filter device, 42 ... Filter, 44 ... Filter case, 46 ... Seal ring, 48 ... Main body portion, 48a ... Inner tubular portion, 48b ... Outer tubular portion, 48c ... Rib, 48d ... Cylindrical portion, 48e ... Disc portion, 48f ... Projection portion, 48g ... Groove, 48h ... Notch, 50 ... Lid portion, 50a ... Cylindrical portion, 50b ... First ceiling portion , 50c ... Connection part, 50d ... Second ceiling part, 50e ... Pillar part, 60a ... Inner hole, 60b ... Outer hole, 60c ... Outer path, 60d ... Inner path, 100 ... Electronic device, 200 ... External space

Claims (8)

A heat generating member (10),
A housing (20) in which the heat generating member is housed in a housing space (22) and the housing space is watertightly sealed;
A filter device (40) which is provided in the casing and which prevents liquid in the external space (200) from entering the storage space and allows ventilation between the storage space and the external space;
Equipped with
The filter device has a filter case (44) having a plurality of ventilation paths for allowing the accommodation space to ventilate with the external space, and is waterproof and breathable, and is disposed in the filter case, and all of the above A filter (42) for closing the ventilation path,
The filter case has a main body part (48) provided in the housing and in which the filter is arranged, and a lid part (50) fixed to the main body part to cover the filter,
Each of the main body portion and the lid portion has both a first path (60a, 60d) and a second path (60b, 60c) formed so as not to intersect with the first path as the ventilation path. Formed,
The opening on the heat generating member side in the first path and the opening on the heat generating member side in the second path are located on the opposite side to the direction of gravity with respect to the heat generating member,
The opening on the side of the heat generating member in the first path has a shorter shortest distance to the heating member than the opening on the side of the heating member in the second path ,
The main body is
A first cylindrical portion (48a) having a cylindrical shape and forming the first path by an inner peripheral surface;
A second cylindrical portion (48d) having a cylindrical shape surrounding the outer peripheral surface of the first cylindrical portion and forming the second path by the inner peripheral surface;
An electronic device having .   The electronic device according to claim 1, wherein the filter device includes one of the filters that closes all the ventilation paths formed in the filter case. A communication hole (32) for communicating the accommodation space and the external space is formed in the housing,
The electronic device according to claim 1 or 2, wherein the filter case is formed of a member different from the housing, is at least partially disposed in a space surrounded by the communication hole, and is fixed to the housing. .   The electronic device according to claim 1, wherein the filter case is formed of the same member as the housing. The housing (20) for housing the heat generating member (10) in the watertightly sealed housing space (22) suppresses the liquid in the external space (200) from entering the housing space, and the housing space. A filter device that allows ventilation between the external space and
A filter case (44) having a plurality of ventilation paths for allowing the accommodation space to ventilate with the external space;
A filter (42) which is waterproof and breathable, is arranged in the filter case, and closes all the ventilation paths,
The filter case has a main body part (48) provided in the housing and in which the filter is arranged, and a lid part (50) fixed to the main body part to cover the filter,
Each of the main body portion and the lid portion has both a first path (60a, 60d) and a second path (60b, 60c) formed so as not to intersect with the first path as the ventilation path. Formed,
The opening on the heat generating member side in the first path and the opening on the heat generating member side in the second path are located on the opposite side to the direction of gravity with respect to the heat generating member,
The opening on the side of the heat generating member in the first path has a shorter shortest distance to the heating member than the opening on the side of the heating member in the second path ,
The main body is
A first cylindrical portion (48a) having a cylindrical shape and forming the first path by an inner peripheral surface;
A second cylindrical portion (48d) having a cylindrical shape surrounding the outer peripheral surface of the first cylindrical portion and forming the second path by the inner peripheral surface;
Filter device having . The filter device according to claim 5 , further comprising: one filter that closes all of the ventilation paths formed in the filter case. A communication hole (32) for communicating the accommodation space and the external space is formed in the housing,
The filter device according to claim 5 or 6 , wherein the filter case is formed of a member different from the housing, is at least partially disposed in a space surrounded by the communication hole, and is fixed to the housing. . The filter case is filtering apparatus according to claim 5 or claim 6 which is formed by the same member and the housing.

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