Cooling structure of on-board electronic unit

Abstract

This on-board cooling structure (1, 1A, 1B, 1C) comprises an assembly comprising: an electronic unit (2) which is disposed in such a posture that one side surface thereof in a thickness direction is along a surface of a vehicle body panel (P) and which includes a blower fan; and a cover (3). A case (20) for the electronic unit (2) has an opening (21) which is open in the thickness direction and an air outlet (22) which is open in a first direction orthogonal to the thickness direction. The cover (3) has an air inlet (33) which is disposed to face the opening (21) and is open in a second direction orthogonal to the thickness direction but different from the first direction, and an incoming air flow path (34) for communication between the air inlet (33) and the opening (21) is formed between the cover and the case (20).

Description

Cooling structure for electronic units mounted on vehicles

[0001] The present invention relates to a cooling structure for an electronic unit mounted on a vehicle.

[0002] Patent Document 1 proposes an electronic unit box that houses an electronic unit that performs electrical control of a vehicle and is equipped with a cooling structure for the electronic unit.

[0003] In the electronic unit box described above, an air layer is formed between an outer primary wall and an inner secondary wall as a coolant flow path, and the electronic unit is housed within the secondary wall. The electronic unit is cooled by air circulating within the air layer. In this electronic unit box, the width of the air layer on the exhaust side is narrower than the width on the intake side. Alternatively, the width of the air layer gradually narrows from the intake side to the exhaust side. This configuration keeps the air circulating within the air layer at a low temperature, uniformizing the temperature of the electronic unit, thereby effectively cooling the entire electronic unit and preventing deformation of the electronic unit due to temperature differences.

[0004] Japanese Patent Application Publication No. 11-354960

[0005] The electronic unit box needs to have a large space including an intake and exhaust space.

[0006] An object of the present invention is to provide a cooling structure for an electronic unit mounted on a vehicle that can efficiently cool the electronic unit even in a narrow space where the thickness is limited.

[0007] According to one aspect of the present invention, a cooling structure for an electronic unit mounted on a vehicle includes an assembly of an electronic unit and a cover, with one surface in a thickness direction aligned with a surface of a vehicle body panel. The electronic unit includes electronic components, a blower fan, and a case. The case has an opening opening in the thickness direction and an exhaust port opening in a first direction perpendicular to the thickness direction. The cover has an air intake port facing the opening and opening in a second direction perpendicular to the thickness direction but different from the first direction, and an air intake flow path is formed between the cover and the case, connecting the air intake port and the opening.

[0008] According to the above configuration, it is possible to efficiently cool the electronic unit even in a narrow space where the thickness direction is limited.

[0009] FIG. 1 is a partially cross-sectional perspective view of a luggage compartment of a vehicle equipped with a cooling structure according to a first embodiment of the present invention, as viewed from the rear. FIG. 2 is a perspective view of a cooling structure according to the first embodiment, including an electronic unit and a cover. FIG. 3 is an exploded perspective view of FIG. 2. FIG. 4 is a perspective view of the electronic unit in FIG. 2 with the cover removed. FIG. 5 is a cross-sectional view of the cooling structure of FIG. 2 taken along a vertical plane passing through the opening of the cover of the electronic unit, as viewed from the front of the vehicle. FIG. 6 is a cross-sectional view of the cooling structure of FIG. 2 taken along a horizontal plane passing through the opening of the case of the electronic unit, as viewed from above the vehicle. FIG. 7 is a cross-sectional view of the cooling structure of FIG. 2 taken along a vertical plane passing through a first wall portion of the cover, as viewed from the right side of the vehicle. FIG. 8 is a cross-sectional view of the cooling structure of FIG. 1 taken along a vertical plane passing through a position rearward of the bracket, as viewed from the rear of the vehicle. FIG. 9 is a cross-sectional view of the cooling structure of FIG. 1 taken along a vertical plane passing through the opening of the case of the electronic unit, as viewed from the rear of the vehicle. FIG. 10A is a side view of the cooling structure of FIG. 2 taken along a vertical plane passing through the opening of the case of the electronic unit, as viewed from the right side of the vehicle. FIG. 10B is a side view of a cooling structure according to another embodiment, as seen from the right side of the vehicle. FIG. 11 is a partially cross-sectional perspective view of a luggage compartment of a vehicle provided with a cooling structure according to a second embodiment of the present invention, as seen from the rear of the vehicle. FIG. 12A is a cross-sectional view of the cooling structure of FIG. 11 taken along a horizontal plane passing through the opening of the case of the electronic unit, as seen from above the vehicle. FIG. 12B is a cross-sectional view taken along line XIIB-XIIB of FIG. 12A. FIG. 13 is a side view of a cooling structure according to the second embodiment, including an electronic unit, a cover, and a duct, as seen from the right side of the vehicle. FIG. 14 is a partially cross-sectional perspective view of a luggage compartment of a vehicle provided with a cooling structure according to a modified example of the second embodiment, as seen from the rear of the vehicle.

[0010] An embodiment of the present invention will be described in detail below with reference to the drawings. In the drawings, the front of the vehicle is indicated by FR, the rear of the vehicle by RR, the right side of the vehicle by RH, the left side of the vehicle by LH, the top of the vehicle by UP, and the bottom of the vehicle by DN. In the following description, the terms "front," "rear," "right," "left," "up," and "down" refer to the above vehicle directions unless otherwise specified. In addition, in figures other than Figures 8 and 9, the side trim 71 is omitted to make the electronic unit 2, cover 3, etc. more clearly visible. In addition, in figures other than Figures 10A and 10B, the harness H is omitted.

[0011] First Embodiment A cooling structure 1 for an electronic unit 2 mounted on a vehicle according to a first embodiment will be described with reference to FIGS. 1 to 10A. As shown in FIG. 1, the cooling structure 1 includes an assembly 9 of an electronic unit 2 and a cover 3, and is provided in the rear of the vehicle, more specifically, in the luggage compartment LG of the vehicle. The electronic unit 2 of this embodiment is a DC-AC inverter that converts DC power from a high-voltage battery mounted on the vehicle into AC power (100 V in Japan, 120 V in North America, and 220 V in Europe, China, etc.) for use in home appliances. In other words, the electronic unit 2 switches, generating heat loss. For this reason, the electronic unit 2 needs to be cooled.

[0012] The luggage compartment LG is a space formed behind the rear seat S, and if the rear seat S is foldable, it also includes the space created when the rear seat S is folded down. As shown in Figures 1, 8, and 9, the luggage compartment LG includes a wheel house 5 for the left rear tire T, a floor panel 6, and a side trim 71, which is an interior trim located on the inside of the vehicle compartment (towards the center of the vehicle in the vehicle width direction) relative to the wheel house 5. The wheel house 5 and floor panel 6 are also referred to as vehicle body panels P.

[0013] The wheel well 5 is a part of a metal side panel of the vehicle and accommodates the left rear tire T of the vehicle outside the passenger compartment. As shown in FIGS. 1 , 8 , and 9 , the wheel well 5 has an inner wall surface 5a, which is the surface facing the passenger compartment and extends in the front-to-rear and up-to-down directions, and an inclined surface 5b extending integrally from the upper edge of the inner wall surface 5a toward the upper left. A sub-bracket 50 for fixing the bracket 4 is welded to the lower part of the inclined surface 5b. The wheel well 5 is formed of metal, but the material is not particularly limited. For example, the wheel well 5 may be formed of resin or fiber-reinforced resin. Furthermore, although the assembly 9 is mounted on the left wheel well 5 side in this embodiment, it may also be mounted on the right wheel well 5 side. In this case, the configuration of the cooling structure 1 according to this embodiment may be reversed left and right.

[0014] As shown in FIG. 1 , the floor panel 6 is a metal plate having a surface extending in the front-rear and left-right directions, and forms the floor surface of the luggage compartment LG. A floor trim 72, which is an interior trim connected to the lower edge of a side trim 71, is provided on the upper surface of the floor panel 6. The left edge of the floor panel 6 is fixed to the lower part of the inner wall surface 5a of the wheelhouse 5 by bolts, welding, or the like. Two bolt holes are provided on the left end of the floor panel 6 for fixing two lower extension portions 41 of a bracket 4 (described below) with bolts BT and nuts NT. While the floor panel 6 is made of metal, the material is not particularly limited and may be made of, for example, resin or fiber-reinforced resin.

[0015] An assembly 9 is fixed to the wheel house 5 and the floor panel 6 via brackets 4. In this embodiment, the assembly 9 is arranged so that its surface is aligned along the inner wall surface 5a of the wheel house 5, rather than along the floor panel 6, in order to improve the storage capacity of the luggage compartment LG.

[0016] As shown in FIGS. 8 and 9 , the side trim 71 is a resin plate having a surface extending in the front-rear and up-down directions (a surface extending along the inner wall surface 5a of the wheel well 5) and a surface extending along the inclined surface 5b of the wheel well 5. The side trim 71 has a lower portion extending to the floor panel 6 and an upper portion extending to the vehicle ceiling. The side trim 71 is disposed closer to the interior of the vehicle than the wheel well 5, bracket 4, electronic unit 2, and cover 3. As shown in FIGS. 8 and 9 , the bracket 4 and assembly 9 are disposed in a space SP enclosed by the side trim 71, wheel well 5, and floor panel 6. In other words, the side trim 71 is disposed to cover the assembly 9 on the side opposite the wheel well 5. As shown in FIG. 9 , the side trim 71 has a plurality of slit-shaped air vents 71a in an air intake area SE near an air intake port 33 of the cover 3 (described later) that connect the space on the wheel well 5 side with the space inside the vehicle interior. The side trim 71 is made of resin or the like, but the material is not particularly limited and may be, for example, metal or fiber-reinforced resin. The shape and number of the air vent 71a are also not limited to those described above. For example, the shape may be circular, and the number may be one.

[0017] The bracket 4 is a member for fixing the assembly 9 to the luggage compartment LG and is fixed to the wheel well 5 and floor panel 6 (vehicle body panel P) as shown in FIG. 1 . The bracket 4 is formed into a substantially flat plate shape by press-forming a high-tensile steel plate. As shown in FIGS. 2 and 3 , the bracket 4 has a central plate-shaped portion 40, side extensions 41, a lower extension 41, sub-extensions 42, and a fixing portion 43. The central plate-shaped portion 40 has a surface that extends in the front-to-rear and up-to-down directions. The upper extensions 41 extend integrally from the upper left and right corners of the central plate-shaped portion 40. The lower extensions 41 extend integrally to the right from the lower left and right corners of the central plate-shaped portion 40. The sub-extensions 42 extend integrally forward from a position slightly below the center of the front edge of the central plate-shaped portion 40. The fixing portions 43 are located rearward and below the central plate-shaped portion 40.

[0018] The central plate-shaped portion 40 is formed with a plurality of beads 40a extending in the front-rear direction, and a flange is formed on the periphery of the central plate-shaped portion 40. The beads 40a and flanges contribute to improving the strength and rigidity of the central plate-shaped portion 40. The upper extension portion 41 is a fixing portion for fixing the bracket 4 to the sub-bracket 50 and also a fixing portion to which the cover 3 is fixed. The lower extension portion 41 is a fixing portion for fixing the bracket 4 to the floor panel 6. The sub-extension portion 42 is a fixing portion for fixing the bracket 4 to the inner wall surface 5a of the wheelhouse 5. The fixing portion 43 is a fixing portion for fixing the cover 3. Each extension portion 41, sub-extension portion 42, and fixing portion 43 is formed with a bolt hole for fixing. The bracket 4 is formed of metal, but the material is not particularly limited and may be formed of, for example, resin or fiber-reinforced resin.

[0019] As described above, the electronic unit 2 is an inverter. As shown in FIGS. 1 to 3 , the electronic unit 2 is fixed to the cover 3, and is fixed to the bracket 4 via the cover 3. The electronic unit 2 includes a case 20, electronic components 23, cooling fins 24, a blower fan 25, and a harness terminal (harness connection portion) 26. The electronic components 23 and the cooling fins 24 are shown in FIG. 5 but are omitted from FIGS. 6, 9, and 12A.

[0020] The electronic components 23 are driven by electricity supplied through the harness terminals 26 and generate heat. The cooling fins 24 absorb the heat generated by the electronic components 23 and dissipate it into the air. The blower fan 25 includes a fan and a drive source such as a motor that rotates the fan. The blower fan 25 generates an airflow by rotation of the fan to cool the cooling fins 24. The drive source is driven by electricity supplied through the harness terminals 26. The case 20 has a box shape and houses the electronic components 23, the cooling fins 24, and the blower fan 25 inside. Note that the electronic unit 2 may not include the cooling fins 24 and may instead be configured to directly cool the electronic components 23 with the airflow generated by the blower fan 25.

[0021] As shown in FIG. 4 , the case 20 of the electronic unit 2 has a front surface 20a facing right, a back surface 20b facing left, an upper surface 20c facing upward, a lower surface 20d facing downward, a front surface 20e facing forward, and a rear surface 20f facing rearward. The electronic unit 2 is disposed such that the front surface 20a of the case 20 is aligned with the surface of the side trim 71 and the back surface 20b of the case 20 is aligned with the inner wall surface 5a of the wheelhouse 5. When the assembly 9 is attached to the bracket 4, the back surface 20b of the case 20 is spaced apart from the central plate-shaped portion 40 of the bracket 4. The "thickness direction" generally refers to a direction perpendicular to the direction of extension of a flat object. In this embodiment, the direction perpendicular to the front surface 20a and back surface 20b of the case 20 is defined as the thickness direction of the electronic unit 2 (case 20). The thickness direction of the electronic unit 2 coincides with the thickness direction of the assembly 9. The case 20 does not have to be strictly rectangular, but may have any shape as long as it has mutually orthogonal or nearly orthogonal faces in which the opening 21 and the exhaust port 22 described below can be provided.

[0022] 4 and 7 , an opening 21 that opens to the right is provided in approximately the center of the surface 20a of the case 20. In other words, the opening 21 is provided on the surface 20a, which is the surface of the case 20 opposite the wheelhouse 5 and the bracket 4. The opening 21 is an opening through which air is drawn from the outside of the case 20 into the inside of the case 20 by the blower fan 25 (to take in air for cooling). Bolt holes for fixing the cover 3 are provided at the four corners of the surface 20a of the case 20. In this embodiment, the opening 21 is circular and located approximately in the center, but this is not limited to this and any shape and location may be used.

[0023] An exhaust port 22 that opens rearward, more specifically, toward the rear of the wheelhouse 5, is provided on the rear surface 20f of the case 20. The exhaust port 22 is an opening for exhausting air that has been drawn into the case 20 from the opening 21 by the blower fan 25 to the outside of the case 20. In this embodiment, the shape of the exhaust port 22 is rectangular, but is not limited to this and may be any shape.

[0024] Two harness terminals 26 protrude downward to form a harness connection portion on the underside 20d of the case 20. As shown in Fig. 10A, a harness H extending from a high-voltage battery mounted on the vehicle is connected to the harness terminals 26.

[0025] The cover 3 is formed by press-forming a high-tensile steel plate. The press-formed steel plate is fastened at several locations with rivets RT to form the cover 3 into a box shape. The electronic unit 2 is attached to the cover 3. As shown in FIGS. 1, 8, and 9, the cover 3, with the electronic unit 2 attached, is fixed to a bracket 4 on a side closer to the passenger compartment than the wheel house 5. As a result, the electronic unit 2 is housed in the space formed by the cover 3 and the bracket 4.

[0026] As shown in Fig. 2, the cover 3 has a main body 30 that has a surface extending in the front-rear and up-down directions and faces the surface 20a of the case 20. The lower end of the main body 30 is located lower than the lower end of the case 20 and higher than the lower end of the bracket 4. The main body 30 has a first surface 30a, a second surface 30b located to the left of the first surface 30a (toward the case 20), and a third surface 30c located to the left of the second surface 30b. The main body 30 also has a first wall 30d that connects the first surface 30a to the second surface 30b and the third surface 30c, and a second wall 30e that connects the second surface 30b to the third surface 30c.

[0027] The first surface 30a is larger than the opening 21 of the case 20 and faces the opening 21 so as to cover the entire opening 21. The first surface 30a extends from near the upper portion of the opening 21 downward below the lower end of the surface 20a of the case 20. The first wall portion 30d is integral with the first surface 30a so as to surround the three peripheries of the first surface 30a (rear, upper, and front) and extends leftward from the first surface 30a. The lower portions of the first surface 30a and the first wall portion 30d open downward, forming an air intake port 33 for drawing air from the outside of the case 20 and the cover 3. The first surface 30a and the first wall portion 30d form an air intake flow path 34 between the surface 20a of the case 20 and the first wall portion 30d, which connects the air intake port 33 and the opening 21. The opening 21 of the electronic unit 2 is located within the air intake flow path 34.

[0028] 9, the intake port 33 opens into a space SP between the wheel well 5, the floor panel 6, and the side trim 71. The area near the intake port 33 forms an intake area SE for drawing in air to be used for cooling electronic components.

[0029] As shown in FIGS. 2 and 7 , the second surface 30b has a plurality of through holes 36 above the opening 21 and the first surface 30a, i.e., in a portion of the cover 3 facing the upper end surface of the case 20 where the air intake passage 34 is not provided. The plurality of through holes 36 allows air to circulate between the space between the case 20 and the cover 3 and the external space. For example, hot air trapped in the space between the case 20 and the cover 3 is discharged to the external space through the plurality of through holes 36. Depending on the conditions, air may flow from the outside into the space between the case 20 and the cover 3 through the plurality of through holes 36. In this case, the air that has flowed in is sucked through the opening 21 and exhausted through the exhaust port 22. Note that the shape and number of the through holes 36 are not limited to those described above. For example, the shape may be a slit, and the number may be one. Note that by arranging the through holes 36 so that they open in the left-right direction rather than the up-down direction, foreign matter such as moisture can be prevented from entering the interior of the assembly 9 through the through holes 36.

[0030] The third surface 30 c has bolt holes BH for fixing the case 20 to the cover 3 , which are provided at positions corresponding to the bolt holes BH of the case 20 .

[0031] As shown in FIG. 2 , the cover 3 has an upper surface portion 31a extending integrally to the left from the upper edges of the second surface 30b and the third surface 30c, a front surface portion 31b extending integrally to the left from the front edge of the front third surface 30c, and a rear surface portion 31c extending integrally to the left from the rear edge of the rear third surface 30c. As described above, the lower surface of the cover 3 is open downward and serves as an air intake 33. The cover 3 also has an extension portion 32 extending upward integrally from the upper edge of the front surface portion 31b and an extension portion 32 extending forward integrally from the lower edge of the front surface portion 31b. The cover 3 also has an extension portion 32 extending rearward integrally from the rear edge of the upper surface portion 31a and an extension portion 32 extending rearward integrally from the lower edge of the rear surface portion 31c. Each extension portion 32 of the cover 3 has a bolt hole BH for securing the cover 3 to the bracket 4.

[0032] The upper surface portion 31a of the cover 3 covers the upper surface 20c of the case 20. The front surface portion 31b of the cover 3 covers the front surface 20e of the case 20 and extends below the lower end of the case 20. The lower end of the front surface portion 31b is located higher than the lower end of the bracket 4. The rear surface portion 31c of the cover 3 covers the rear surface 20f of the case 20 from a position below the exhaust port 22 on the rear surface 20f of the case 20 and extends below the lower end of the case 20. The lower end of the rear surface portion 31c is located higher than the lower end of the bracket 4. The cover 3 has a rear opening 35 above the rear surface portion 31c for exposing the exhaust port 22.

[0033] As shown in Figures 5 to 7, the three upper, front, and rear end faces of the surface 20a of the case 20, which are located on three sides of the opening 21 and do not have the air intake flow path 34, block or to a certain extent impede the flow of air between the air intake flow path 34 and the external space, together with the second surface 30b and the third surface 30c of the cover 3. However, since air is drawn in by the blower fan 25, the three end faces of the surface 20a of the case 20 and the cover 3 do not need to be completely sealed, and some air leakage is permitted. In other words, it is sufficient that air is drawn into the air intake flow path 34 mainly through the air intake port 33. Note that the location that blocks or to a certain extent impedes the flow of air between the air intake flow path 34 and the external space may be two or one end faces of the surface 20a of the case 20.

[0034] More specifically, as shown in FIG. 5 , the portion of the surface 20a of the case 20 having the opening 21 where the intake flow path 34 is provided is separated from the first surface 30a of the cover 3 by a separation distance (first separation distance) h1 in the left-right direction (vehicle width direction, thickness direction). Furthermore, the end face of the surface 20a of the case 20 having the opening 21 where the intake flow path 34 is not provided is separated from the second surface 30b of the cover 3 by a separation distance (second separation distance) h2 in the left-right direction. The separation distance (first separation distance) h1 is greater than the separation distance (second separation distance) h2. The separation distance (second separation distance) between the third surface 30c of the cover 3 and the attachment point of the case 20 and the cover 3, i.e., the attachment point of the case 20 and the cover 3, is zero. Furthermore, as shown in FIG. 7 , the width of the intake flow path 34 in the front-rear direction is equal to or greater than the width of the opening 21 in the front-rear direction. Furthermore, the cross-sectional area of ​​the exhaust port 22 shown in Figure 8 is equal to or greater than the cross-sectional area of ​​the intake flow path. In this embodiment, the cross-sectional shape of the intake flow path 34 is rectangular, but this is not limited to this and any shape may be used. Furthermore, the effective cross-sectional area of ​​the exhaust port 22 may be equal to or greater than the effective cross-sectional area of ​​the intake flow path.

[0035] As shown in FIG. 10A , the air intake 33 of the cover 3 opens in the same direction as the harness connection port 27, which opens downward to allow access to the harness terminals 26. By opening the air intake 33 downward, the position of the air intake 33 can be aligned with the position of the harness connection port 27. Here, for example, in a cooling structure 1A according to another embodiment (hereinafter referred to as a comparative embodiment) shown in FIG. 10B , the air intake 33 is provided to open forward, which is a different direction from the opening direction of the harness connection port 27, and the positions of the air intake 33 and the harness connection port 27 do not match. In this cooling structure 1A, the area required for the layout of the assembly 9 is larger than that of the cooling structure 1 according to the first embodiment by the area corresponding to the air intake 33 or the harness connection port 27. As such, the cooling structure 1 according to the first embodiment can reduce the area required for the layout of the assembly 9 compared to the cooling structure 1A according to the comparative embodiment.

[0036] 1 , 8 and 9 , the assembly 9 is disposed with the back surface 20b of the electronic unit 2 along the inner wall surface 5a of the wheel house 5, and the main body 30 of the cover 3 along the surface of the side trim 71. The assembly 9 is disposed in the narrow space between the wheel house 5 and the side trim 71.

[0037] Next, the flow of air during cooling in the cooling structure 1 according to the first embodiment will be described with reference to FIGS. 5 to 7 and 9 . First, as indicated by the arrow AIR in FIG. 6 , an airflow is generated from the opening 21 of the case 20 toward the exhaust port 22 by the operation of the blower fan. Next, as indicated by the arrow AIR in FIGS. 5 , 7 , and 9 , the generated airflow draws air from the intake area SE between the wheel well 5, floor panel 6, and side trim 71, located below the assembly 9, upward through the intake port 33 of the cover 3 and into the intake flow path 34. At the same time, when the air from the intake area SE is drawn through the intake port 33, air from inside the vehicle cabin flows into the intake area through the vent 71 a of the side trim 71, as shown in FIG. 9 . The air drawn into the intake flow path 34 passes through the opening 21 and hits the cooling fins 24, and the heated air is exhausted from the exhaust port 22. As shown in FIG. 6 , the heated air exhausted from the exhaust port 22 is discharged toward the space behind the vehicle between the rear of the wheel well 5 and the side trim 71. Because the space behind the vehicle is wide and unobstructed, the exhausted heated air flows toward the rear and is efficiently diffused in the rear space, dissipating heat. Furthermore, because the spaces behind, above, and in front of the wheel well 5 are interconnected, the exhausted heated air also diffuses into these spaces above and in front. For this reason, the heated air exhausted from the exhaust port 22 is less likely to be drawn into the intake port 33. Furthermore, the heat of the heated air exhausted from the exhaust port 22 is less likely to be transferred to the air in the intake area SE.

[0038] The procedure for assembling the electronic unit 2, the cover 3, and the bracket 4 of the cooling structure 1 according to the first embodiment, and the procedure for attaching it to the vehicle body panel P will be described.

[0039] 1 to 3 and 8, the bracket 4 is placed in the luggage compartment LG of the vehicle, and the bolts BT inserted into the bolt holes BH are fastened with the nuts NT to secure the two lower extensions 41 of the bracket 4 to the left end of the floor panel 6, which has two bolt holes. With the bracket 4 secured to the floor panel 6, the two upper extensions 41 of the bracket 4 are aligned with the sub-bracket 50.

[0040] Next, the electronic unit 2 is fixed to the cover 3. Specifically, with the bolt holes BH provided at the four corners of the front surface 20a of the case 20 of the electronic unit 2 aligned with the bolt holes BH provided in the third surface 30c of the cover 3, the bolts BT are inserted into the bolt holes BH of the cover 3 and screwed into the bolt holes BH of the case 20. The assembled electronic unit 2 and cover 3 constitute an assembly 9.

[0041] 3, the cover 3 with the electronic unit 2 fixed thereto is attached to the bracket 4. Specifically, by fastening the bolts BT and nuts NT inserted through the bolt holes BH, the extension portions 32 of the cover 3 are fixed to the corresponding extension portions 41, sub-extension portions 42, and fixing portions 43 of the bracket 4. In this manner, the electronic unit 2, cover 3, and bracket 4 of the cooling structure 1 are assembled and attached to the vehicle body panel P.

[0042] As described above, in the first embodiment, the assembly 9 is attached to the wheel house 5 and the floor panel 6 with one surface in the thickness direction aligned with the inner wall surface 5a of the wheel house 5, which is a side panel of the vehicle. The fastening method is not limited to the above. For example, the number and positions of the bolts BT, nuts NT, and bolt holes BH are not limited to the above. Furthermore, instead of fastening and fastening methods using the bolts BT, nuts NT, and bolt holes BH, fastening methods using welding, adhesives, screws, fitting, etc. may be used. The shape, position, number, etc. of each fastening portion for fastening each member are also not limited to the above. Furthermore, the order in which each member is fastened is not limited to the above.

[0043] The effects of the first embodiment are described below. (1) The assembly 9 of the electronic unit 2 and cover 3 is disposed such that its thickness-wise surface is aligned with the inner wall surface 5a of the wheel well 5, which is a vehicle body panel. Furthermore, the air intake 33 opens downward, the air intake passage 34 is provided in the left-right direction (vehicle width direction), and the exhaust passage is not provided in the left-right direction, but the exhaust port 22 opens rearward. This allows the space in the exhaust direction of the exhaust port 22 to be effectively utilized as an exhaust passage, eliminating the need for an exhaust passage in the thickness direction of the electronic unit 2, thereby reducing the thickness size of the assembly 9. This allows the assembly 9 to be disposed in a narrow space where the thickness and the air intake space are limited. Furthermore, the air intake 33 and the exhaust port 22 open in different directions in the thickness direction. Therefore, heated air exhausted from the exhaust port 22 flows and diffuses in a direction different from the location of the air intake 33, making it less likely to be drawn in again through the air intake 33. This enables efficient cooling of the electronic unit 2 even in a narrow space where the thickness direction is limited.

[0044] (2) When the vehicle space is considered as a flow path, the flow path cross-sectional area (or effective cross-sectional area) of the vehicle space to which the heated air exhausted from the exhaust port 22 is exhausted is larger than the flow path cross-sectional area (or effective cross-sectional area) of the intake flow path 34. Therefore, pressure loss is less likely to occur in the air flow from the air intake port 33 through the intake flow path 34 and the exhaust port 22 to the vehicle space, eliminating the need to increase the output of the blower fan 25. This allows the electronic unit 2 requiring cooling to be arranged in a limited space (e.g., the luggage compartment LG of the vehicle) with high space efficiency, and allows for the routing of ducts as needed. Furthermore, as described above, because the flow path cross-sectional area (or effective cross-sectional area) of the vehicle space to which the heated air is exhausted is larger than the flow path cross-sectional area (or effective cross-sectional area) of the intake flow path 34, there is no need to seal the intake flow path 34. This eliminates the need for a structure to seal the intake flow path 34, thereby reducing the increase in manufacturing costs for components and the increase in costs and weight due to the increase in parts.

[0045] (3) When placing the electronic unit 2 inside the vehicle, if the opening 21 is too close to other components such as the side trim 71, air intake will not be efficient. In the first embodiment, the cover 3 is provided in a position facing the opening 21 of the electronic unit 2. This ensures a sufficient distance between the opening 21 and other components, allowing for efficient air intake. Furthermore, providing the cover 3 on the electronic unit 2 can provide the function of protecting the electronic unit 2, either alone or together with the bracket 4, against obstacles during a rear-end collision, etc.

[0046] (4) The thicknesswise separation distance h1 between the cover 3 and the portion of the surface 20a of the case 20 having the opening 21 where the intake flow path 34 is provided is greater than the thicknesswise separation distance h2 between the cover 3 and the end face of the surface 20a of the case 20 having the opening 21 where the intake flow path 34 is not provided. This reduces pressure loss, facilitating air flow toward the opening 21. Furthermore, the intake flow path 34 can be easily provided without providing sealing components on the end face portion of the case 20. Because the intake flow path 34 draws air using the blower fan 25, some air leakage is permitted, unlike flow paths that require waterproofing. Furthermore, by closing the space on the exhaust port 22 side (reducing the separation distance between the case 20 and the cover 3), heated air exhausted from the exhaust port 22 is less likely to be drawn through the opening 21. Furthermore, the end faces of the surface 20a of the case 20 having the opening 21 where the intake flow path 34 is not provided are the three end faces located on three sides of the opening 21. Therefore, the exhausted heated air is less likely to be taken into the intake passage 34 from the three end faces.

[0047] (5) The assembly 9 is installed on the side panel of the luggage compartment LG of the vehicle (more specifically, the wheel well 5). The exhaust port 22 opens toward the rear of the vehicle, and the intake port 33 opens toward the bottom of the vehicle. Therefore, a wide, open space SP exists between the side panel of the luggage compartment LG and the side trim 71, particularly toward the rear, top, and front of the vehicle, ensuring sufficient space for diffusing the heated air exhausted from the exhaust port 22. Furthermore, by vertically arranging the electronic unit 2 between the side panel of the luggage compartment LG and the side trim 71, the storage capacity of the luggage compartment LG can be improved. Furthermore, because the electronic unit 2 is an inverter that provides household power, arranging the electronic unit 2 in the luggage compartment LG allows for easy user access.

[0048] (6) A plurality of circular through-holes 36 are provided in the cover 3 above the opening 21 of the case 20. This makes it easier to exhaust hot air trapped between the case 20 and the cover 3 to the outside through the plurality of through-holes 36 provided above the cover 3. Depending on the conditions, air may flow from the outside into the space between the case 20 and the cover 3 through the plurality of through-holes 36. In this case, the air that has flowed in is sucked in through the opening 21 and exhausted through the exhaust port 22. Therefore, even in this case, it is easier to exhaust hot air trapped between the case 20 and the cover 3 to the outside.

[0049] (7) The assembly 9 is installed on a side panel of the luggage compartment LG of the vehicle (more specifically, the wheel well 5), and the opening direction of the intake port 33 is downward. In addition, the harness connection port 27 is provided so that the harness connection terminal (harness connection portion) 26 provided at the bottom of the case 20 is accessible and opens in the same direction as the intake port 33. Therefore, compared to the comparative embodiment in which the intake port 33 and the harness connection port 27 face in different directions, the area required for the layout of the assembly 9 can be reduced. In addition, the harness connection portion can be protected from obstructions during a rear-end collision, etc.

[0050] (8) A side trim 71 is provided to cover the assembly 9 on the side opposite the side panel (more specifically, the wheelhouse 5) of the assembly 9. The side trim 71 also has a vent hole 71a near the air intake 33. Therefore, if the side trim 71 covers the electronic unit 2, heat tends to build up in the space there. However, the vent hole 71a makes it easier for unheated air from the vehicle cabin to be drawn into the air intake area SE, thereby lowering the temperature of the air drawn through the air intake 33. In particular, if the side trim 71 is made of a resin material, heat buildup may be significant, so providing the air vent hole 71a in the side trim 71 is more effective. Furthermore, the air intake flow path 34 is provided on the side trim 71 side of the assembly 9 in the thickness direction. Therefore, the air intake 33 can be positioned near the vent hole 71a of the side trim 71, making it easier for unheated air from the vehicle cabin to be drawn into the air intake area SE through the vent hole 71a.

[0051] (9) The assembly 9 is installed in the wheel well 5 of the luggage compartment LG of the vehicle. In particular, between the wheel well 5 of the luggage compartment LG and the side trim 71, there is a space SP that is widely connected to the rear, upper, and front of the vehicle. Therefore, the heated air exhausted from the exhaust port 22 is diffused into the spaces behind, above, and in front of the wheel well 5. Therefore, a sufficient space can be secured to diffuse the heated air exhausted from the exhaust port 22.

[0052] (10) When the assembly 9 is attached to the bracket 4, the rear surface 20b of the case 20 is spaced apart from the central plate portion 40 of the bracket 4. This facilitates heat dissipation from the rear surface 20b of the case 20.

[0053] Second Embodiment A cooling structure 1B for an electronic unit 2 mounted on a vehicle according to a second embodiment will be described with reference to Figures 11 to 13. The second embodiment has the same configuration as the first embodiment described above, except for the provision of a duct 8, which will be described below. Therefore, parts with the same configuration will be assigned the same reference numerals and descriptions thereof will be omitted.

[0054] 11 , the cooling structure 1B includes a resin duct 8 that extends from the exhaust port 22 of the case 20 of the electronic unit 2 toward the rear of the vehicle. The duct 8 has a tubular shape with a duct connection port 8a at one end and a duct exhaust port 8b at the other end that are connected to each other. The duct connection port 8a is connected to the exhaust port 22 near the rear opening 35 of the cover 3. The duct exhaust port 8b is located rearward of the rear end of the wheel house 5 and spaced rearward from the exhaust port 22, and opens into a rear space of the wheel house 5 between the rear of the wheel house 5 and the side trim 71.

[0055] The duct 8 exhausts the air exhausted from the exhaust port 22 via the duct connection port 8a to the space behind the wheel house 5 through a duct flow path (exhaust flow path) which is the space inside the tube.

[0056] The shape of the duct 8 is not limited to a tube, as long as it can exhaust the air exhausted from the exhaust port 22 to a separate space. The duct 8 is formed of resin, but the material is not particularly limited and may be, for example, metal or fiber-reinforced resin. Furthermore, the connection between the duct connection port 8a and the exhaust port 22 may be completely or partially sealed, as long as it can introduce most of the exhaust air from the exhaust port 22 into the tube. For example, a sealing member such as a resin packing may be disposed between the duct connection port 8a and the exhaust port 22 to improve the sealing between the duct connection port 8a and the exhaust port 22.

[0057] The flow path cross-sectional area (or effective cross-sectional area) of the duct flow path inside the duct 8 shown in Fig. 12B is larger than the flow path cross-sectional area (or effective cross-sectional area) of the exhaust port 22 shown in Fig. 8 and the flow path cross-sectional area (or effective cross-sectional area) of the intake flow path 34 shown in Fig. 6. Note that the flow path cross-sectional area (or effective cross-sectional area) of the duct flow path may be smaller than the flow path cross-sectional area (or effective cross-sectional area) of the exhaust port 22.

[0058] 13 , when viewed from the right, the duct 8 is connected to the exhaust port 22 on the rear side of the assembly 9 and extends rearward. Also, when viewed from the right, the rear end of the case 20 is located forward of the rear end of the bracket 4 and the duct 8.

[0059] In the second embodiment, the space into which the duct exhaust port 8b opens is not limited to the space behind the wheel house 5 between the rear of the wheel house 5 and the side trim 71. As an example of this, a cooling structure 1C according to a modified example of the second embodiment will be described. As shown in Fig. 14 , in the cooling structure 1C, the duct exhaust port 8b opens through a hole that penetrates the vehicle body panel P behind the wheel house 5 into a space that communicates with a vehicle draft door (not shown) for discharging intake air from an air conditioner or the like to the outside of the vehicle.

[0060] The following describes the effects of the second embodiment and the modified example of the second embodiment. The second embodiment and the modified example of the second embodiment have the same configuration as the first embodiment, except that the location where air is exhausted (exhaust port 22) in the first embodiment is changed to the duct exhaust port 8b of the duct 8. Therefore, the second embodiment and the modified example of the second embodiment can also achieve the effects (1) to (10) of the first embodiment described above.

[0061] (1) In the second embodiment and the modified example of the second embodiment, a duct 8 is provided that is connected to the exhaust port 22 of the case 20. Therefore, the duct 8 allows the air exhausted from the exhaust port 22 to be exhausted to a space farther from the intake port 33, and prevents the heated air exhausted from the exhaust port 22 from being sucked back into the intake port 33. Furthermore, the flow path cross-sectional area (or effective cross-sectional area) of the duct 8 is larger than the flow path cross-sectional area (or effective cross-sectional area) of the intake flow path 34. This reduces pressure loss and further promotes exhaust from the intake port 33 to the duct exhaust port 8b. Furthermore, there is no need to increase the output of the blower fan 25, and there is no need to seal the intake flow path 34.

[0062] (2) In the second embodiment, the assembly 9 is installed in the body panel of the luggage compartment LG of the vehicle (more specifically, the wheel well 5), the opening direction of the exhaust port 22 is toward the rear of the vehicle, and the duct 8 extends into the space behind the wheel well 5. Therefore, the air exhausted from the exhaust port 22 can be exhausted into the relatively large space behind the body panel of the luggage compartment LG, which is distant from the exhaust port 22, and the heated air exhausted from the exhaust port 22 can be efficiently dispersed.

[0063] (3) In the second embodiment and the modified example of the second embodiment, the opening direction of the exhaust port 22 is set to the rear of the vehicle, the duct 8 extends rearward, the assembly 9 is attached to the vehicle body panel P via the bracket 4, and the rear end of the case 20 of the electronic unit 2 is positioned forward of the rear end of the bracket 4. Therefore, in the event of a rear-end collision, there is a risk that an interfering object will hit the electronic unit 2 from behind, but the electronic unit 2 is positioned at least forward of the bracket 4. Therefore, the bracket 4 can suppress interference with the electronic unit 2 from the interfering object, and short-circuiting of the conductive parts of the electronic unit 2 can be reduced. Furthermore, even if an interfering object does interfere with the electronic unit 2, the interference occurs via the duct 8 rather than the electronic components 23, thereby reducing the risk of short-circuiting of the conductive parts of the electronic unit 2.

[0064] (4) In the modified example of the second embodiment, the duct exhaust port 8b is opened to the space connected to the draft cover through a hole that penetrates the vehicle body panel. Therefore, the heated air exhausted from the duct exhaust port 8b is discharged into the negative pressure space created by the draft cover. This more reliably prevents the heated air exhausted from the duct exhaust port 8b from being sucked back into the intake port 33.

[0065] Other Embodiments The first embodiment, comparative embodiment, second embodiment, and modified example of the second embodiment of the present invention have been described above, but the following configurations can also be adopted in these embodiments.

[0066] In all of the above-described embodiments, the cooling structure 1 to 1C includes an assembly 9 of the electronic unit 2 and the cover 3, but may further include at least one of a bracket 4, a wheelhouse 5, a floor panel 6, and a side trim 71.

[0067] In all the above-described embodiments, the cover is provided with a plurality of through holes 36, but the through holes 36 may not be provided.

[0068] In all of the above-described embodiments, the side trim 71 is provided with the vent hole 71 a, but the vent hole 71 a does not have to be provided. Even if the side trim 71 does not have the vent hole 71 a, the air exhausted from the exhaust port 22 flows toward the large space behind and is diffused, so that the exhausted heated air can be prevented from being sucked in through the intake port 33.

[0069] In all of the above-described embodiments, the main body 30 of the cover 3 has three surfaces, the first surface 30a to the third surface 30c, spaced at different distances from the surface 20a of the case 20. However, this is not limited to this. For example, the main body 30 of the cover 3 may have two surfaces spaced at different distances from the surface 20a of the case 20. In this case, for example, the second surface 30b and the third surface 30c may be formed as a single surface spaced at the same distance from the surface 20a of the case 20. This single surface may then be provided with multiple through holes 36 and multiple bolt holes BH for fastening. Furthermore, the main body 30 of the cover 3 may have four or more surfaces spaced at different distances from the surface 20a of the case 20. Even with such a configuration, pressure loss can be reduced.

[0070] In all of the above-described embodiments, the width of the intake flow path 34 is equal to or greater than the width of the opening 21, but this is not limiting. For example, the width of the intake flow path 34 may be smaller than the width of the opening 21. Furthermore, the upper end of the intake flow path 34 is located above the upper end of the opening 21, but this is not limiting.

[0071] In all of the above-described embodiments, the opening 21 is provided on the surface 20a of the case 20, which is the surface opposite to the wheel well 5 and bracket 4. The cover 3 faces the surface 20a of the case 20 and forms an intake flow path 34 together with the surface 20a. In other words, the intake flow path 34 is located on the opposite side of the case 20 from the wheel well 5 and bracket 4. However, the intake flow path 34 may also be located between the case 20 and the wheel well 5 and / or bracket 4. In this case, the intake port 33 is somewhat farther from the air vent 71a of the side trim 71 than in all of the above-described embodiments, but unheated air from within the vehicle cabin can still be taken into the intake area SE through the air vent 71a of the side trim 71.

[0072] In the first and second embodiments and the modified example of the second embodiment, the air intake port 33 is provided to open below the assembly 9, but is not limited to this. As in the comparative embodiment, the air intake port 33 may be provided to open in any of the directions above, forward, or backward of the assembly 9, as long as the air intake port 33 is an opening that opens in a direction perpendicular to the thickness direction of the assembly 9 different from the opening direction of the exhaust port 22.

[0073] In all of the above-described embodiments, the exhaust port 22 is provided only on the rear surface 20f of the case 20. However, the present invention is not limited to this. The exhaust port 22 may be provided on one or more of the upper surface 20c, lower surface 20d, and front surface 20e of the case 20, as long as the exhaust port 22 is located in a direction perpendicular to the thickness direction of the case 20 that is different from the opening direction of the intake port 33.

[0074] In the second embodiment, if the exhaust port 22 is not provided on the rear surface 20f of the case 20, the direction in which the duct 8 extends from the exhaust port 22 is not limited to the rear. For example, if the exhaust port 22 is provided on any of the upper surface 20c, lower surface 20d, and front surface 20e of the case 20, the duct 8 is arranged to extend in a direction corresponding to the opening direction of the exhaust port 22 rather than the rear. If the exhaust ports 22 are provided on two or more side surfaces (multiple directions) of the case 20, the duct 8 may be connected to each exhaust port 22 or at least one corresponding exhaust port 22, and the duct 8 may extend to a position away from the exhaust port 22 and the intake port 33. Even in this configuration, the provision of the duct 8 allows the air exhausted from the exhaust port 22 to be exhausted to a space farther from the intake port 33 of the cover, and prevents the heated air discharged from the exhaust port 22 from being drawn through the intake port 33.

[0075] In all of the above-described embodiments, the electronic unit 2 is an inverter for providing AC power to the user, and is therefore disposed in a position in the luggage compartment LG that is accessible to the user. However, the electronic unit 2 is not limited to an inverter, and may be any unit that includes heat-generating electronic components 23 and requires cooling. In this case, the electronic unit 2 does not need to be disposed in a position that is accessible to the user.

[0076] In all of the above-described embodiments, the assembly 9 is fixed to the vehicle body panel P (wheel housing 5 and floor panel 6) via the bracket 4, and the electronic unit 2 is fixed to the bracket 4 via the cover 3, but this is not limiting. For example, the assembly 9 may be fixed directly to the vehicle body panel P. Also, for example, the electronic unit 2 may be fixed directly to the bracket 4 without the cover 3. These configurations do not substantially change the configurations for achieving the effects of all the above-described embodiments. Therefore, even with these configurations, it is possible to achieve the effects (1) to (10) of the first embodiment and the effects (1) to (4) of the second embodiment and the modified example of the second embodiment.

[0077] In all of the above-described embodiments, the assembly 9 is attached to the wheel well 5. However, this is not limiting. For example, the assembly 9 may be attached to a side panel other than the wheel well 5, which has a space that extends in at least one direction. Furthermore, the assembly 9 is disposed in a posture (vertical placement) in which one side surface in the thickness direction of the assembly 9 is aligned with the inner wall surface 5a of the wheel well 5, which is a side panel of the vehicle. However, this is not limiting. For example, the assembly 9 may be disposed in a posture (flat placement) in which one side surface in the thickness direction of the assembly 9 is aligned with the surface of the floor panel 6 of the vehicle. Furthermore, the assembly 9 is disposed in the luggage compartment LG of the vehicle, but this is not limiting. For example, the assembly 9 may be disposed in a position on a side panel or floor panel in the passenger compartment that has a space that extends in at least one direction. These configurations do not substantially change the configurations for achieving the effects of all of the above-described embodiments. Therefore, these configurations can also achieve the effects (1) to (10) of the first embodiment and the effects (1) to (4) of the second embodiment and the modified example of the second embodiment.

[0078] The present invention has been described above in accordance with the embodiments, but it will be obvious to those skilled in the art that the present invention is not limited to these descriptions and that various modifications and improvements are possible.

[0079] 1, 1A, 1B, 1C: Cooling structure for electronic unit; 2: Electronic unit; 20: Case; 20a: Surface; 21: Opening; 22: Exhaust port; 23: Electronic components; 25: Blower fan; 26: Harness terminal (harness connection portion); 27: Harness connection port; 3: Cover; 33: Air intake port; 34: Air intake flow path; 36: Through hole; 4: Bracket; 5: Wheelhouse (side panel); 71: Side trim (interior trim); 71a: Air vent; 8: Duct; 9: Assembly (electronic unit and cover); P: Body panel (wheelhouse, floor panel, side panel); LG: Luggage compartment; h1: First separation distance; h2: Second separation distance

Claims

1. A cooling structure for an electronic unit mounted on a vehicle, comprising the electronic unit including electronic components, a blower fan for cooling the electronic components, and a case for housing the electronic components and the blower fan, a cover attached to the electronic unit, wherein the assembly of the electronic unit and the cover is arranged in a posture such that one surface on one side in the thickness direction is along the surface of the vehicle body panel of the vehicle, the case has an opening that opens in the thickness direction for intake of air from the outside of the case into the case by the blower fan, and an exhaust port that opens in a first direction orthogonal to the thickness direction for exhausting the air taken into the case from the opening to the outside of the case by the blower fan, and the cover is provided opposite to the opening, has an intake port for intake of air from the outside of the case and the cover, which opens in a second direction orthogonal to the thickness direction and different from the first direction, and forms an intake flow path communicating the intake port and the opening between the cover and the case cooling structure.

2. A first separation distance in the thickness direction between a portion of the surface of the case having the opening where the intake flow path is provided and the cover is larger than a second separation distance in the thickness direction between an end surface of the surface of the case having the opening where the intake flow path is not provided and the cover The cooling structure according to claim 1.

3. The vehicle body panel is a side panel of the cargo compartment of the vehicle, the first direction is at least one of the rear, front, and upper directions of the vehicle, the second direction is the lower direction of the vehicle The cooling structure according to claim 1 or 2.

4. The cover has a through hole above the vehicle relative to the opening The cooling structure according to claim 3.

5. Further comprising a duct connected to the exhaust port and having a flow path cross-sectional area larger than the flow path cross-sectional area of the intake flow path The cooling structure according to claim 1 or 2.

6. The vehicle body panel is arranged in the cargo compartment of the vehicle, the first direction is the rear direction of the vehicle, the duct extends rearward of the vehicle body panel The cooling structure according to claim 5.

7. The assembly is attached to the vehicle body panel via a bracket, the rear end of the case is located forward of the vehicle relative to the rear end of the bracket The cooling structure according to claim 6.

8. The vehicle body panel is a side panel of the luggage compartment of the vehicle, The second direction is below the vehicle, The cooling structure is accessible to a harness connection portion provided below the vehicle of the case, and further includes a harness connection port that opens in the second direction The cooling structure according to claim 1 or 2.

9. The vehicle body panel is a side panel of the luggage compartment of the vehicle, A side trim that is disposed to cover the assembly on the side opposite to the vehicle body panel of the assembly and has a vent hole in the vicinity of the intake port is further provided. The cooling structure according to claim 1 or 2.

10. The vehicle body panel is a wheel house of the luggage compartment of the vehicle The cooling structure according to claim 1 or 2.

11. The assembly is attached to the vehicle body panel via a bracket, The case and the bracket are separated from each other The cooling structure according to claim 1 or 2.