JP6652038B2 - Electronic equipment - Google Patents

Description

  The disclosure herein relates to an electronic device comprising a respiratory filter.

  Patent Literature 1 includes a printed wiring board (circuit board) on which electronic components are mounted, a waterproof case (housing) that houses the circuit board, and a breathing filter attached to a ventilation hole (through hole) of the housing. An electronic device is disclosed.

JP 2007-141959 A

A respiratory filter generally has a filter case, a gas permeable membrane, and a sealing material. The filter case has a cylindrical shape with both ends opened, and is fixed to the housing with the through hole inserted. The gas permeable membrane is arranged in the filter case so as to close one opening of the filter case. The sealing material prevents liquid from entering the storage space from the gap between the filter case and the housing,
Interposed between the filter case and the housing. As the sealing material, for example, an O-ring is used.

  In the conventional electronic device disclosed in Patent Literature 1, the housing is formed as an outer surface, which is a surface on the side of the external space, around the through hole, and is inclined toward the circuit board in the through direction of the through hole as it approaches the center of the through hole. Surface. The sealing material is sandwiched between the inclined surface and the outer surface of the filter case.

  Therefore, a liquid such as cleaning water easily stays on the housing while being in contact with the sealant. In particular, when a gap portion (dent space) is formed between the sealing material and the housing, the liquid tends to stay. If the liquid is a corrosive liquid that corrodes metals, such as water or a solution of calcium chloride used as a snow melting agent due to snow melting, the use of a metal housing will corrode the housing and ensure sufficient waterproofness. It may not be possible. When the liquid is an organic solvent such as oil for vehicle use, for example, the sealing material may be deteriorated and sufficient waterproofness may not be secured.

  Note that a configuration in which the periphery of the through hole in the housing is flat and the sealing material is sandwiched between the flat surface and the outer surface of the filter case is also conceivable, but in this case also, the liquid contacts the sealing material while the housing is in contact with the sealing material. Easy to stay on the body.

  The present disclosure has been made in view of the above problems, and has as its object to provide an electronic device that can suppress a decrease in waterproof performance due to retention of a liquid.

  The present disclosure employs the following technical means to achieve the above object. In addition, the code | symbol in a parenthesis shows the correspondence with the specific means described in embodiment mentioned later as one aspect, and does not limit a technical range.

An electronic device according to one embodiment of the present disclosure includes a circuit board (20),
A housing (30) having a housing space (31) for housing the circuit board, and a through hole (32) for communicating the housing space with an external space;
A filter case (41) having a cylindrical shape with both ends opened and fixed to the housing in a state where the through hole is inserted, and a gas permeable membrane (42) arranged in the filter case so as to close one of the openings. A respiratory filter (40) having a sealing material (44) interposed between the filter case and the housing so as to prevent liquid from entering the storage space from a gap between the filter case and the housing;
With
The casing has an inclined surface (332a) around the through hole as an outer surface that is a surface on the external space side, the inclined surface (332a) moving away from the circuit board in the through direction of the through hole as approaching the center of the through hole.
The filter case has a facing surface (412b) facing the inclined surface,
A sealing material is sandwiched between the inclined surface and the facing surface.

  According to this electronic device, the casing has the inclined surface that moves away from the circuit board as it approaches the center of the through-hole, and the sealing material is sandwiched between the inclined surface and the opposing surface of the filter case. Therefore, it is difficult for the liquid to enter the position of the sealing material. Even if it enters, the liquid flows in a direction away from the sealing material along the inclined surface. That is, it is possible to suppress the liquid from staying on the housing in contact with the sealing material. Therefore, it is possible to suppress a decrease in waterproof performance due to stagnation of the liquid.

FIG. 2 is a plan view of the electronic device according to the first embodiment. FIG. 2 is a sectional view taken along the line II-II in FIG. 1. It is the figure which expanded the area | region III of FIG. It is sectional drawing which shows a comparative example. FIG. 3 is a cross-sectional view illustrating a seal structure between a respiratory filter and a housing in the first embodiment. FIG. 13 is a cross-sectional view illustrating a seal structure between a breathing filter and a housing in the electronic device according to the second embodiment, and corresponds to FIG. 5. FIG. 13 is a cross-sectional view illustrating a seal structure between a breathing filter and a housing in the electronic device according to the third embodiment, and corresponds to FIG. 5. FIG. 16 is a cross-sectional view illustrating a seal structure between a breathing filter and a housing in the electronic device according to the fourth embodiment, and corresponds to FIG. 5.

  A plurality of embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding parts are provided with the same reference signs. A penetration direction of a through hole formed in the housing is indicated by a Z direction, and one direction orthogonal to the Z direction is indicated by an X direction. A direction orthogonal to both the Z direction and the X direction is referred to as a Y direction. Unless otherwise specified, a shape along the XY plane is a planar shape.

(1st Embodiment)
First, a schematic configuration of an electronic device will be described with reference to FIGS. The electronic device is configured as an ECU (Electronic Control Unit) having a waterproof structure. The electronic device is arranged, for example, in an engine room of a vehicle. The electronic device according to the present embodiment is configured as an engine ECU that controls an engine mounted on a vehicle. As shown in FIGS. 1 and 2, the electronic device 10 includes a circuit board 20, a housing 30, and a respiratory filter 40.

  The circuit board 20 has a board 21 and electronic components 22. The substrate 21 is formed by arranging wiring on a base material formed using an electrically insulating material such as a resin. The board 21 is also called a printed board. The substrate 21 is housed in the housing 30 so that the thickness direction of the substrate 21 is the Z direction. The substrate 21 has a substantially planar rectangular shape. Two sides of the four sides of the rectangle are substantially parallel to the X direction, and the remaining two sides are substantially parallel to the Y direction.

  The electronic component 22 is mounted on the board 21. The electronic component 22 forms a circuit together with the wiring of the substrate 21. In the present embodiment, the electronic components 22 are mounted on both surfaces of the substrate 21. The electronic component 22 may be mounted on only one surface of the substrate 21. The circuit board 20 is fixed to the housing 30 by a known fixing method such as screw fastening or adhesion.

  The connector 23 is mounted on the circuit board 20. The connector 23 is disposed at one end in the Y direction with respect to the board 21. The connector 23 has a housing 230 and a plurality of terminals 231. The housing 230 is formed using a resin material. The terminal 231 is formed using a conductive material such as a metal so as to electrically relay a circuit formed on the circuit board 20 and an external device. The plurality of terminals 231 are held by the housing 230. The plurality of terminals 231 are arranged along the X direction.

  In the present embodiment, since the number of terminals is large, the terminals 231 are arranged in multiple stages in the Z direction. The terminal 231 is inserted and mounted on the circuit board 20 (substrate 21). However, surface mount structures can also be employed. In FIG. 2, the insertion mounting structure is simplified and the solder is omitted. A part of the connector 23 thus configured is exposed to the outside through the opening of the housing 30, and the remaining part is housed in the housing 30.

  The housing 30 has a housing space 31 for housing the circuit board 20 and a through hole 32. The housing 30 accommodates a part of the connector 23 and the circuit board 20 therein to protect them. For example, the housing 30 is formed using a metal material such as aluminum in order to improve the heat dissipation of the heat generated by the electronic component 22. For example, in order to reduce the weight of the electronic device 10, the housing 30 is formed using a resin material.

  In the present embodiment, the housing 30 has two members divided in the Z direction, specifically, a case 33 and a cover 34. The case 33 and the cover 34 are both formed using a metal material. The case 33 is formed by aluminum die casting. The cover 34 is formed by pressing an iron-based material. The housing 30 is formed by assembling the case 33 and the cover 34 in the Z direction. The method of assembling the case 33 and the cover 34 is not particularly limited. A well-known assembling method such as screw fastening can be adopted.

  The case 33 has a box shape with one surface opened. The bottom 330 of the case 33 also has a substantially rectangular planar shape corresponding to the substrate 21 having a substantially rectangular planar shape. In the case 33, one of the four side surfaces is open, and the side surface opening is connected to the above-described one surface opening.

  The cover 34 forms the housing space 31 together with the case 33. By assembling the case 33 and the cover 34, the cover 34 closes an opening on one surface of the case 33. Thereby, the opening on the side surface is defined, and an opening for exposing the connector 23 is formed.

  The through hole 32 is a ventilation hole that allows the housing space 31 to communicate with a space outside the electronic device 10. The through-hole 32 is provided to keep the pressure in the storage space 31 equal to the pressure in the external space. An atmospheric pressure sensor is mounted on the substrate 21 as the electronic component 22. The circuit board 20 performs a predetermined process using the information of the air in the external space detected by the atmospheric pressure sensor, that is, the atmospheric pressure information. The through hole 32 is formed in the bottom 330 of the case 33. In the present embodiment, the through hole 32 has a substantially circular shape in plan view. Note that the planar shape of the through hole 32 is not limited to a substantially perfect circular shape. For example, a polygonal shape can be adopted.

  At the peripheral edges of the case 33 and the cover 34, the sealing material 35 is provided between the opposing surfaces of the case 33 and the cover 34, between the opposing surfaces of the case 33 and the housing 230, and between the opposing surfaces of the cover 34 and the housing 230. Is interposed. The sealing material 35 hermetically seals the housing space 31 with respect to an external space (for example, an engine room) of the electronic device 10 and prevents liquid from entering the housing space 31. The sealing material 35 makes the housing space 31 a waterproof space. As the sealing material 35, for example, a silicon-based moisture-curable adhesive can be used.

  The breathing filter 40 suppresses the liquid from entering the accommodation space 31 through the through hole 32 from the external space. As the liquid, for example, rainwater, water used for car washing, water rolled up when the vehicle is running, a solution obtained by melting snow of calcium chloride used as a snow melting agent, and an organic solvent such as brake oil are assumed. The respiratory filter 40 is configured so as to prevent the liquid from entering the storage space 31 and to prevent the ventilation between the storage space 31 and the external space via the through hole 32. The breathing filter 40 is attached to a portion of the housing 30 where the through hole 32 is formed.

  The electronic device 10 configured as described above is arranged such that the Z direction substantially coincides with the top and bottom directions, the case 33 is on the top side (vehicle ceiling side), and the cover 34 is on the ground side (vehicle floor side).

  Next, the structure around the through hole 32 in the case 33, the structure of the breathing filter 40, and the seal structure between the case 33 and the breathing filter 40 will be described with reference to FIG.

  As shown in FIG. 3, the case 33 has a base 331 and a periphery 332 of the opening as the bottom 330. The opening peripheral portion 332 includes a wall surface of the bottom portion 330 that defines the through hole 32, and is a portion within a predetermined range radially outward from the wall surface. The base 331 is a portion of the bottom 330 excluding the opening periphery 332. The inner surface of the bottom part 330 defines the housing space 31, and the outer surface opposite to the inner surface is in contact with the outer space. The outer surface of the bottom 330 corresponds to the outer surface of the housing 30.

  The outer surface of the opening peripheral portion 332 is an inclined surface 332a that moves away from the circuit board 20 in the Z direction as it approaches the center of the through hole 32 in a direction perpendicular to the Z direction (that is, in the radial direction). In FIG. 3, the boundary between the base 331 and the periphery 332 of the opening is indicated by a broken line. Note that the center of the through hole 32 is the center in plan view from the Z direction. That is, it is the center axis of the through hole 32 along the Z direction.

  In the present embodiment, in a plan view from the Z direction, a portion where the inclined surface 332a is formed is the opening peripheral portion 332. Further, the inclination angle of the inclined surface 332a is constant. In addition, at least the peripheral portion of the opening peripheral portion 332 of the base portion 331 has a flat plate shape. The opening peripheral portion 332 has a portion protruding to the top side in the vertical direction with respect to the base portion 331. The thickness of the bottom portion 330 is substantially constant in the peripheral portion of the opening peripheral portion 332, and the thickness of the opening peripheral portion 332 is thicker than this constant thickness portion. The thickness of the opening peripheral portion 332 increases as approaching the through hole 32. The configuration of the opening peripheral portion 332 having the inclined surface 332a is not limited to the above example. An opening peripheral portion 332 having a substantially constant thickness while having the inclined surface 332a may be employed.

  The respiratory filter 40 has a filter case 41, a gas permeable membrane 42, a filter cover 43, and a sealing material 44. The filter case 41 has a cylindrical shape with both ends opened, and is fixed to the case 33 with the through-hole 32 inserted. The filter case 41 is formed using a resin material.

  The filter case 41 has a main body 410, a plurality of claws 411, and an extension 412. In FIG. 3, the boundaries between the main body 410, the claw 411, and the extension 412 are indicated by broken lines. The main body 410 extends in the Z direction and has a tubular shape with both ends opened. The main body 410 is also called a cylinder. In the present embodiment, the main body 410 has a cylindrical shape corresponding to the through hole 32.

  The main body 410 has an inner peripheral surface 410a that is the inner surface of the cylinder and an outer peripheral surface 410b that is the outer surface. The inner peripheral surface 410a forms a ventilation path between the outer space and the housing space 31. The diameter of the outer peripheral surface 410b substantially matches the diameter of the through hole 32. The extension length of the main body 410 is equal to or longer than the extension length of the through hole 32.

  The plurality of claws 411 are for fixing the respiratory filter 40 to the case 33 of the housing 30. The claw portion 411 is continuous with the main body portion 410 and is locked on the inner surface of the bottom portion 330. The plurality of claw portions 411 are provided so as to surround the through holes 32 in a plan view from the Z direction. The claw 411 is connected to an end of the main body 410 on the side of the storage space 31, that is, a lower end. The claw 411 extends radially outward from the lower end of the main body 410. The surface of the claw portion 411 facing the bottom portion 330 is in contact with the inner surface of the opening peripheral portion 332.

  A cutout (not shown) is formed in the main body 410. The notch is formed to have a predetermined depth in the Z direction from a lower end portion different from a portion where the claw portion 411 is continuous. With the notch, the body 410 can be made smaller when the filter case 41 is inserted into the through hole 32. When the claw portion 411 projects to the inner surface side of the case 33, the main body portion 410 returns to the size before being inserted into the through hole 32.

  The extending portion 412 is connected to the main body portion 410 on the outer space side and extends radially outward. In a plan view from the Z direction, the extending portion 412 has a substantially annular shape. The inner peripheral end and the outer peripheral end of the extension portion 412 have a substantially circular shape in plan view. The extension part 412 forms a ventilation path together with the main body part 410. On the upper surface 412a of the extension 412 opposite to the bottom 330, the gas permeable membrane 42 is disposed so as to close one opening of the cylinder.

  The extending portion 412 has a facing surface 412b facing the inclined surface 332a as a part of the lower surface opposite to the upper surface 412a. In the present embodiment, the facing surface 412b is provided substantially parallel to the inclined surface 332a. The facing surface 412b is also called an inclined surface. The extension 412 has a flat surface 412c as a lower surface that is substantially perpendicular to the Z direction. In the plane 412c portion, the thickness of the extension 412 is constant. In the portion where the opposing surface 412b is provided, the thickness of the extending portion 412 becomes larger toward the outside in the radial direction. In the radial direction, the outer peripheral surface 410b is continuous with one end of the flat surface 412c, and the opposing surface 412b is continuous with the other end. The facing surface 412b, the flat surface 412c, the outer peripheral surface 410b, and the inclined surface 332a form a space where the sealing material 44 is arranged.

  As described above, the gas permeable membrane 42 is disposed on the upper surface 412 a of the extension 412 so as to close one opening of the cylinder of the filter case 41. The gas permeable film 42 has waterproofness and gas permeability. The gas permeable membrane 42 is also called a filter. The gas permeable film 42 has water repellency and oil repellency. As the gas permeable film 42, for example, a porous film formed using a fluororesin or polyolefin can be adopted. The gas permeable membrane 42 is fixed to the extension 412 of the filter case 41 by an adhesive (not shown) or the like.

  The filter cover 43 protects the gas permeable film 42 and is arranged to cover the gas permeable film 42. The filter cover 43 has a box shape whose surface on the side of the gas permeable membrane 42 (the filter case 41) is open. An opening 43a is formed in a part of the side wall of the filter cover 43 for ventilation. The filter cover 43 is fixed to the filter case 41, and the gas permeable membrane 42 is disposed in a space defined by the filter cover 43 and the upper surface 412 a of the extension 412 of the filter case 41. The filter cover 43 is also called a lid or a cap.

  The sealing material 44 is interposed between the filter case 41 and the case 33 so as to prevent liquid from entering the housing space 31 through a gap between the filter case 41 and the case 33 of the housing 30. The seal member 44 is provided in an annular shape so as to surround the through hole 32. As the sealing material 44, any material can be adopted as long as it can seal the outer space outside the sealing material 44 and the housing space 31 in a watertight manner. In the present embodiment, a rubber-like elastic body is used as the seal member 44. More specifically, a rubber O-ring is employed as the seal member 44. In a state where the O-ring is not compressed, the cross section of the O-ring has a substantially perfect circular shape.

  The sealing material 44 is sandwiched between the inclined surface 332 a of the case 33 and the facing surface 412 b of the filter case 41. The sealing material 44 is compressed by the inclined surface 332a and the opposing surface 412b. The seal member 44 is in contact with at least the inclined surface 332a and the opposing surface 412b in an elastically deformed state. A reaction force due to elastic deformation of the seal member 44 acts on the inclined surface 332a and the opposing surface 412b. As a result, the claw 411 firmly contacts the inner surface of the bottom 330, and the respiratory filter 40 is fixed to the case 33 by the claw 411 and the sealant 44. Note that a configuration in which the sealing material 44 contacts at least one of the outer peripheral surface 410b and the flat surface 412c in addition to the inclined surface 332a and the opposing surface 412b may be employed.

  Such a sealing material 44 (O-ring) is attached to the filter case 41 in advance. Then, by inserting the filter case 41 to which the seal member 44 is attached into the through hole 32, the seal member 44 is sandwiched between the inclined surface 332a and the opposing surface 412b.

  Next, the effects of the electronic device 10 described above will be described with reference to FIGS. FIG. 4 shows a reference example. In FIG. 4, the reference numerals of the respective elements in the reference example are obtained by adding “r” to the end of the reference numerals of the relevant elements of the present embodiment. 4 and 5 are simplified diagrams of FIG. 3 for convenience.

  In the reference example shown in FIG. 4, as the outer surface of the opening peripheral portion 332r, which is a part of the bottom portion 330r, approaches the center of the through hole for ventilation in the radial direction, the inclined surface 332ar moves away from the circuit board in the Z direction. I have. That is, the opening peripheral portion 332r has a shape in which the opening peripheral portion 332r is lowered toward the accommodation space side with respect to the base portion 331r. The filter case 41r has a main body 410r, a claw 411r, and an extension 412r. The extending portion 412r extends radially outward from one end of the main body portion 410, and has a flat plate shape having a substantially constant thickness over the entire area. That is, the entire lower surface of the extension 412 is a plane 412cr.

  The seal member 44r is an O-ring made of rubber. The sealing material 44r is in contact with the inclined surface 332ar, the outer peripheral surface 410br, and the flat surface 412cr. In such a configuration, the contact portion between the sealing material 44r and the case 33r is closer to the ground in the vertical direction than the peripheral portion of the opening peripheral portion 332r on the outer surface of the base 331r. Therefore, the liquid 50r such as high-pressure washing water easily enters the position where the sealant 44r is disposed. Further, since the gap 45r communicating with the external space is formed between the sealant 44r and the case 33r, the liquid 50r easily stays in the gap 45r. That is, the liquid 50r easily stays on the case 33r while being in contact with the sealant 44r.

  For this reason, when the liquid 50r is a corrosive liquid that corrodes a metal such as water or a solution of calcium chloride used as a snow-melting agent by melting snow, the interface between the metal case 33r and the sealant 44r corrodes to form a gap. Further, the stagnation liquid 50r continuously enters the gap. Therefore, there is a possibility that sufficient waterproofness cannot be ensured. On the other hand, when the liquid 50r is an organic solvent such as oil on a vehicle, for example, the sealing material 44r may be deteriorated and sufficient waterproofness may not be secured.

  Note that a configuration is also conceivable in which the opening peripheral portion 332r of the case 33r is flattened and the sealing material 44r is sandwiched between the flat surface and the flat surface 412cr of the filter case 41r. Is likely to stay on the case 33r while being in contact with.

  On the other hand, in the present embodiment, as shown in FIG. The seal material 44 is sandwiched between the facing surface 412 b of the sealing member 41. The contact portion between the sealing material 44 and the case 33 is on the upper side (upper side) in the vertical direction than the peripheral portion of the opening peripheral portion 332 on the outer surface of the base 331. Therefore, it is difficult for the liquid 50 such as high-pressure washing water to enter the position of the seal member 44. Even if the liquid 50 enters, the liquid 50 flows along the inclined surface 332a in a direction away from the sealing material 44 as shown by a solid arrow in FIG. That is, it is possible to suppress the liquid 50 from staying on the case 33 in contact with the sealing material 44. Therefore, it is possible to suppress a decrease in waterproof performance due to the stagnation of the liquid 50.

  In particular, in the present embodiment, an O-ring that is a rubber-like elastic body is employed as the seal member 44. In this case, a gap 45 communicating with the external space is formed between the seal member 44 and the case 33. However, as described above, the liquid 50 hardly enters the position of the seal member 44, and even if it does, the liquid 50 flows (discharges) along the inclined surface 332a in a direction away from the seal member 44. Therefore, even when the sealing material 44 having the gap 45 formed between the case 33 and the case 33 is used, it is possible to effectively suppress a decrease in the waterproof performance due to the stagnation of the liquid 50.

  Further, in the present embodiment, the inclined surface 332a and the facing surface 412b are parallel to each other. When the sealing material 44 is elastically deformed, the reaction force received from each of the inclined surface 332a and the opposing surface 412b is opposite to each other, so that the sealing material 44 is stabilized between the inclined surface 332a and the opposing surface 412b. Can be held. That is, it is possible to stably seal.

(2nd Embodiment)
This embodiment can refer to the preceding embodiment. Therefore, description of the same parts as those of the electronic device 10 shown in the preceding embodiment will be omitted.

  In the present embodiment, as shown in FIG. 6, the facing distance between the inclined surface 332a and the facing surface 412b increases as the distance from the through hole 32 increases in the radial direction. Here, the facing distance is a distance in a direction orthogonal to the inclined surface 332a. For example, if the facing distance at the entrance of the space is L1 and the facing distance at the upper end (opening end) of the inclined surface 332a is L2, the distance L2 is longer than the distance L1. When the inclination angle of the inclined surface 332a with respect to the XY plane is θ1, and the inclination angle of the facing surface 412b with respect to the XY plane is θ2, the inclination angle θ2 is larger than the inclination angle θ1. The inclination angles θ1 and θ2 are both acute angles.

  As described above, in the space defined by the inclined surface 332a, the outer peripheral surface 410b, the plane 412c, and the opposing surface 412b, the opposing distance becomes longer toward the back. Therefore, when assembling the respiratory filter 40 (the filter case 41) to the case 33, the seal member 44, which is a rubber-like elastic body, receives the pressure from the inclined surface 332a and the opposing surface 412b, That is, it moves to the back side where the facing distance is long. Accordingly, the seal member 44 is held at a higher position with respect to the outer surface of the base 331, and the liquid 50 hardly reaches the position of the seal member 44. In the present embodiment, the sealing material 44 contacts each of the inclined surface 332a, the outer peripheral surface 410b, the flat surface 412c, and the opposing surface 412b.

  In addition, since the entrance of the space defined by the inclined surface 332a, the outer peripheral surface 410b, the flat surface 412c, and the facing surface 412b is narrow, the sealing material 44 does not easily move even when the high-pressure liquid 50 such as high-pressure washing water is applied. Therefore, the contact pressure of the sealing material 44 on the inclined surface 332a and the opposing surface 412b is stabilized, and the leakage can be suppressed.

  Further, since the sealing material 44 is held on the far side where the facing distance is long, the cross-sectional shape orthogonal to the extending direction approaches a perfect circle shape. Thereby, the gap 45 formed between the sealing material 44 and the case 33 becomes large. In other words, the opening angle formed by the sealing member 44 and the inclined surface 332a increases. Therefore, even if the liquid 50 enters the position of the sealing material 44, the liquid 50 is easily discharged from the gap 45. In other words, the liquid 50 is unlikely to stay in the gap 45. Therefore, it is possible to effectively suppress a decrease in waterproof performance due to the stagnation of the liquid 50.

(Third embodiment)
This embodiment can refer to the preceding embodiment. Therefore, description of the same parts as those of the electronic device 10 shown in the preceding embodiment will be omitted.

  In the present embodiment, as shown in FIG. 7, the inclined surface 332a has an arc shape that is convex outward. The inclined surface 332a is convex toward the facing surface 412b. The seal member 44 is in contact with at least the arcuate inclined surface 332a and the opposing surface 412b. In the present embodiment, it further contacts the outer peripheral surface 410b.

  According to this, since the inclined surface 332a has an arc shape convex outward, the gap 45 formed between the seal member 44 and the case 33 is larger than in a configuration in which the inclination angle is constant. Therefore, even if the liquid 50 enters the position of the sealing material 44, the liquid 50 is easily discharged from the gap 45. In other words, the liquid 50 is unlikely to stay in the gap 45. Therefore, it is possible to effectively suppress a decrease in waterproof performance due to the stagnation of the liquid 50. In FIG. 7, an inclined surface having a constant inclination angle is indicated by a dashed line for reference.

(Fourth embodiment)
This embodiment can refer to the preceding embodiment. Therefore, description of the same parts as those of the electronic device 10 shown in the preceding embodiment will be omitted.

  In the present embodiment, as shown in FIG. 8, a facing distance L3 between the inclined surface 332a and the facing surface 412b is longer than a contact length L4 between the sealing material 44 and the inclined surface 332a. The facing distance L3 is a length in a direction orthogonal to the inclined surface 332a. The contact length L4 is a length of a portion where the seal member 44 and the inclined surface 332a are in contact in the inclined direction. In other words, the contact length L4 is a length of a portion where the seal member 44 and the inclined surface 332a are in contact with each other in a direction orthogonal to the extending direction of the annular seal member 44. The seal member 44 is in contact at least with the inclined surface 332a and the opposing surface 412b.

  According to this, since the facing distance L3 is longer than the contact length L4, the cross-sectional shape of the sealing material 44 approaches a perfect circle. Thereby, the gap 45 formed between the sealing material 44 and the case 33 becomes large. Therefore, even if the liquid 50 enters the position of the sealing material 44, the liquid 50 is easily discharged from the gap 45. In other words, the liquid 50 is unlikely to stay in the gap 45. Therefore, it is possible to effectively suppress a decrease in waterproof performance due to the stagnation of the liquid 50.

  The disclosure of this specification is not limited to the illustrated embodiments. The disclosure includes the illustrated embodiments and variations thereon based on those skilled in the art. For example, the disclosure is not limited to the combination of the elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosed technical scope is not limited to the description of the embodiments. Some of the disclosed technical ranges are indicated by the appended claims, and should be construed to include all modifications within the meaning and scope equivalent to the appended claims. .

  Although an example of the engine ECU has been described as the electronic device 10, the electronic device 10 is not limited to this. Furthermore, it is not limited to an electronic control unit (ECU). The present invention can be applied to any waterproof electronic device including the circuit board 20, the housing 30, and the breathing filter 40.

  Although the example in which the respiratory filter 40 is fixed to the case 33 (the housing 30) by the claw portion 411 and the sealing material 44 has been described, the present invention is not limited to this. Other fixing methods, such as screw fastening, may be employed.

  Although the example in which the breathing filter 40 is attached to the bottom 330 of the case 33 has been described, the present invention is not limited to this. In the use environment, it may be attached to the housing 30 on the top side in the up-down direction.

  As the seal member 44, an example of a rubber-like elastic body has been described. However, the first, third, and fourth embodiments are not limited to this. For example, even when the gel-like sealing material 44 is employed, the gap 45 formed between the sealing member 44 and the inclined surface 332a shown in the third embodiment is increased to effectively reduce the waterproof performance due to the retention of the liquid 50. Can be suppressed. For example, even when a moisture-curable adhesive is used as the sealing material 44, it is difficult for the liquid 50 such as high-pressure cleaning water to enter the sealing material 44. Even if the liquid 50 enters, the liquid 50 flows in the direction away from the seal member 44 along the inclined surface 332a. Therefore, it is possible to suppress a decrease in waterproof performance due to the stagnation of the liquid 50.

  Although the example in which the part of the outer surface of the bottom part 330 in a predetermined range radially outward from the opening end of the through hole 32 is the inclined surface 332a is shown, the present invention is not limited to this. The inclined surface 332a may be formed around the through hole 32. For example, a portion in a predetermined range radially outward from the opening end of the through hole 32 may be a plane orthogonal to the Z direction, and the inclined surface 332a may be continuous with this plane.

DESCRIPTION OF SYMBOLS 10 ... Electronic device, 20 ... Circuit board, 21 ... Substrate, 22 ... Electronic components, 23 ... Connector, 230 ... Housing, 231 ... Terminal, 30 ... Housing, 31 ... Housing space, 32 ... Through hole, 33 ... Case, 330 ... Bottom part, 331 ... Base part, 332 ... Opening part, 332a ... Slope surface, 34 ... Cover, 35 ... Seal material, 40 ... Respiratory filter, 41 ... Filter case, 410 ... Body part, 410a ... Inner peripheral surface, 410b ... outer peripheral surface, 411 ... claw portion, 412 ... extension portion, 412a ... upper surface, 412b ... opposing surface, 412c ... flat surface, 42 ... gas permeable membrane, 43 ... filter cover, 44 ... sealing material, 45 ... gap, 50 ... liquid

Claims (6)

A circuit board (20);
A housing (30) having a housing space (31) for housing the circuit board and a through hole (32) for communicating the housing space with an external space;
A filter case (41) having a tubular shape with both ends opened and fixed to the housing in a state where the through hole is inserted, and a gas permeable membrane (41) arranged in the filter case so as to close one of the openings 42) and a sealing material (44) interposed between the filter case and the housing so as to prevent liquid from entering the storage space through a gap between the filter case and the housing. A respiratory filter (40);
With
The casing has an inclined surface (332a) around the through hole as an outer surface that is a surface on the external space side, the inclined surface (332a) moving away from the circuit board in the through direction of the through hole as approaching the center of the through hole. And
The filter case has a facing surface (412b) facing the inclined surface,
An electronic device in which the sealing material is sandwiched between the inclined surface and the facing surface.   The electronic device according to claim 1, wherein the sealing material is a rubber-like elastic body.   The electronic device according to claim 1, wherein the inclined surface and the facing surface are parallel to each other.   The electronic device according to claim 2, wherein a facing distance between the inclined surface and the facing surface becomes longer as approaching the through hole.   The electronic device according to claim 1, wherein the inclined surface has an arc shape that is convex outward.   3. The electronic device according to claim 1, wherein a facing distance between the inclined surface and the facing surface is longer than a contact length of the sealing material and the inclined surface in a direction in which the inclined surface is inclined. 4.

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