In-vehicle electronic device

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The in-vehicle electronic device enhances heat dissipation by using a phase change cooler extending from the heat generating component to the connector, addressing thermal resistance issues and maintaining temperature gradients for efficient heat dissipation.

JP7602009B2Active Publication Date: 2024-12-17ASTEMO LTD

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Patent Information

Application Number: JP2023502051
Authority / Receiving Office: JP · JP
Patent Type: Patents
Current Assignee / Owner
Priority Date: 2021-02-24
Filing Date: 2021-09-28
Publication Date: 2024-12-17
Estimated Expiration: 2041-09-28

AI Technical Summary

Technical Problem

The existing heat dissipation structures in vehicle-mounted electronic devices suffer from high thermal resistance at connection points, making it difficult to meet the higher heat dissipation requirements compared to conventional computers.

Method used

An in-vehicle electronic device design featuring a phase change cooler that extends from the heat generating component toward the connector, utilizing a heat transfer member and a heat transfer member to maximize heat diffusion, with the phase change cooler integrated into the housing or circuit board to maintain temperature differences and enhance heat dissipation.

Benefits of technology

The design maximizes the heat diffusion ability of the phase change cooler, ensuring high heat dissipation performance by maintaining temperature gradients and efficiently circulating refrigerant phases to dissipate heat effectively.

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Abstract

The present invention provides an on-vehicle electronic device capable of maximizing the heat diffusion ability of a phase change cooler and ensuring high heat dissipation performance. This on-vehicle electronic device 100 is provided with a heating component 6 having a surface 6a mounted to a circuit board 4 and another surface 6b on the opposite side from the surface 6a in the thickness direction of the circuit board 4, a connector 5 mounted to the circuit board 4 and to be connected to an external device, a housing 1 containing the circuit board 4 to which the heating component 6 and the connector 5 are mounted, a phase change cooler 9 extending from the heating component 6 mounted to the circuit board 4 toward the connector 5 and transferring heat by a phase change of a coolant, and a heat transfer member 8 in contact with the other surface 6b of the heating component 6 and the housing 1 or the phase change cooler 9.

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Description

[Technical field]

[0001] The present invention relates to an in-vehicle electronic device. [Background technology]

[0002] In electronic devices such as computers, phase-change coolers such as vapor chambers or heat pipes are used as a means for cooling heat-generating components such as CPUs. This type of phase-change cooler is a cooler that includes an evaporator that absorbs heat from heat-generating components by changing the phase of a liquid-phase refrigerant to a gas phase without using power as described in Patent Document 1, and a condenser that dissipates heat from the gas-phase refrigerant into the air by changing the phase of the gas-phase refrigerant to a liquid phase.

[0003] Patent Document 2 describes a portable computer having a heat dissipation structure using a heat pipe as a heat dissipation structure for dissipating heat from a heat-generating component mounted on a circuit board to a housing. In the computer of Patent Document 2, the heat-generating component is connected to a heat receiving plate, the heat receiving plate is connected to a heat pipe, the heat pipe is connected to a connector, the connector is connected to a hinge, and the hinge is connected to a case, thereby realizing a heat dissipation structure for dissipating heat from the heat-generating component to the housing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-92074 A [Patent Document 2] Japanese Patent Application Publication No. 11-102235 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the heat dissipation structure of Patent Document 2 has a large number of components, which increases the thermal resistance at the connection between the components. In particular, for in-vehicle electronic devices that require higher heat dissipation performance than the computer of Patent Document 2, it is difficult to meet the heat dissipation performance requirements even if the heat dissipation structure of Patent Document 2 is adopted.

[0006] The present invention has been made in consideration of the above, and aims to provide an in-vehicle electronic device that can maximize the thermal diffusion capacity of a phase change cooler and ensure high heat dissipation performance. [Means for solving the problem]

[0007] In order to solve the above problems, the in-vehicle electronic device of the present invention comprises a heat-generating component having one side mounted on a circuit board and another side opposite the one side in the thickness direction of the circuit board, a connector mounted on the circuit board and connected to an external device, a housing that accommodates the circuit board on which the heat-generating component and the connector are mounted, a phase change cooler that extends from the heat-generating component mounted on the circuit board toward the connector and transports heat accompanied by a phase change of a refrigerant, and a heat transfer member in contact with the other side of the heat-generating component and with the housing or the phase change cooler. Effect of the Invention

[0008] According to the present invention, it is possible to provide an in-vehicle electronic device that can maximize the heat diffusion capacity of a phase change cooler and ensure high heat dissipation performance. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0009] [Figure 1] 1 is an exploded perspective view showing a configuration of an in-vehicle electronic device according to a first embodiment. [Diagram 2] 2 is an explanatory diagram showing a schematic cross section of the in-vehicle electronic device taken along line AA' shown in FIG. [Diagram 3] FIG. 11 is an explanatory diagram of an in-vehicle electronic device according to a second embodiment. [Figure 4] FIG. 11 is an explanatory diagram of an in-vehicle electronic device according to a third embodiment. [Diagram 5] FIG. 11 is a perspective view showing the external configuration of an in-vehicle electronic device according to a fourth embodiment. [Figure 6] 6 is a perspective view showing a cross section of the in-vehicle electronic device taken along line BB' shown in FIG. 5. [Figure 7] FIG. 2 is an explanatory diagram of an arrangement structure of a cover having a first top plate portion and a second top plate portion, and a low-profile heat-generating component and a high-profile heat-generating component. [Figure 8] FIG. 13 is an explanatory diagram of an arrangement structure of a cover that does not have a first top panel portion and a second top panel portion, and a low-profile heat-generating component and a high-profile heat-generating component. [Figure 9] FIG. 13 is an explanatory diagram of an example of an in-vehicle electronic device according to a fifth embodiment. [Figure 10] FIG. 13 is an explanatory diagram of another example of the in-vehicle electronic device according to the fifth embodiment. [Figure 11] FIG. 13 is an explanatory diagram of an in-vehicle electronic device according to a sixth embodiment. [Figure 12] FIG. 13 is an explanatory diagram of an example of an in-vehicle electronic device according to a seventh embodiment. [Figure 13] FIG. 23 is an explanatory diagram of another example of the in-vehicle electronic device according to the seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that components with the same reference numerals in each embodiment have the same functions in each embodiment unless otherwise specified, and the description thereof will be omitted.

[0011] [Embodiment 1] An in-vehicle electronic device 100 according to a first embodiment will be described with reference to FIGS. Fig. 1 is an exploded perspective view showing the configuration of an in-vehicle electronic device 100 of embodiment 1. Fig. 2 is an explanatory diagram showing a schematic cross section of the in-vehicle electronic device 100 taken along line AA' shown in Fig. 1.

[0012] The in-vehicle electronic device 100 is an electronic device such as an ECU that is mounted on a vehicle. The in-vehicle electronic device 100 includes a housing 1, a circuit board 4 such as a printed circuit board housed in the housing 1, a connector 5, a heat-generating component 6, and an electronic component 7 mounted on the circuit board 4, a heat transfer member 8 in contact with the heat-generating component 6, and a phase change cooler 9 for dissipating heat from the heat-generating component 6.

[0013] The housing 1 is a box-shaped member that houses a circuit board 4 on which a connector 5, a heat-generating component 6, and an electronic component 7 are mounted. The housing 1 is made of a metal material such as aluminum, copper, or stainless steel, or a resin material. The housing 1 includes a box-shaped cover 2 and a box-shaped case 3 (or a plate-shaped base) that is shallower than the cover 2.

[0014] The cover 2 covers the circuit board 4 while being spaced apart in the thickness direction of the circuit board 4 from the heat-generating components 6 mounted on the circuit board 4. The cover 2 has a top plate portion 21 that intersects with the thickness direction of the circuit board 4 and faces the circuit board 4, and a side plate portion 22 that is connected to the top plate portion 21 and extends along the thickness direction of the circuit board 4.

[0015] As shown in FIG. 1, a heat dissipation fin may be provided on the outer surface of the top plate portion 21. As shown in FIG. 1 and FIG. 2, a portion of the top plate portion 21 covering the connector 5 may be formed so as to be longer in distance from the circuit board 4 in the thickness direction of the circuit board 4 than a portion of the top plate portion 21 covering the heat generating component 6. The side plate portion 22 includes a first side plate portion 22a adjacent to one end 4a of the circuit board 4 in a direction along the circuit board 4 (in-plane direction of the circuit board 4) and a second side plate portion 22b adjacent to the other end 4b of the circuit board 4 in the direction along the circuit board 4. The first side plate portion 22a may be a side plate portion 22 having an opening portion 23 that exposes the connector 5 mounted on the circuit board 4 to the outside. The second side plate portion 22b may be a side plate portion 22 parallel to the first side plate portion 22a.

[0016] The side plate 22 and the opening 23 may be provided on the case 3 instead of the cover 2, or may be provided on both the cover 2 and the case 3. That is, the side plate 22 and the opening 23 may be parts that form the side plate and the opening of the housing 1. The top plate 21 may also be a part that forms the top plate of the housing 1.

[0017] The connector 5 is mounted on the circuit board 4 and is connected to an external device of the in-vehicle electronic device 100. A harness 51 (see FIG. 3) bundling wires that form a transmission path for signals for communicating with the external device may be connected to the connector 5. As shown in FIG. 1, the connector 5 is mounted on at least one end 4a of the circuit board 4 in the direction along the circuit board 4. That is, the connector 5 is mounted on one of a pair of parallel sides of the rectangular circuit board 4.

[0018] The heat generating component 6 is an electronic component (high heat generating component) that generates a relatively large amount of heat among the electronic components mounted on the circuit board 4. The heat generating component 6 is an electronic component whose junction temperature (Tj) when energized is higher than that of other electronic components mounted on the circuit board 4. The heat generating component 6 is an electronic component whose difference between the maximum rated junction temperature (Tjmax) and the junction temperature when energized (Tj) is smaller than that of other electronic components. The heat generating component 6 may be configured by an arithmetic processing device including a processor such as a CPU, MPU, or GPU. The heat generating component 6 is formed in a plate shape, and has one surface 6a mounted on the circuit board 4 and the other surface 6b opposite to the one surface 6a in the plate thickness direction of the circuit board 4, as shown in FIG. 2. The heat generating component 6 is mounted at least on the other end 4b of the circuit board 4 in the direction along the circuit board 4, as shown in FIG. 1. That is, the heat generating component 6 is mounted on the other of a pair of parallel sides of the rectangular circuit board 4.

[0019] The electronic component 7 is an electronic component mounted on the circuit board 4 other than the connector 5 and the heat-generating component 6. The electronic component 7 is an electronic component that generates less heat than the heat-generating component 6. The electronic component 7 may be configured by an electronic component including, for example, an interface circuit such as a communication IC, or a power supply circuit such as a power supply IC.

[0020] The heat transfer member 8 is a heat transfer member that contacts the other surface 6b of the heat generating component 6 and the housing 1 or the phase change cooler 9. The heat transfer member 8 is a member that dissipates heat from the heat generating component 6 to the housing 1 or the phase change cooler 9. As shown in FIG. 2, the heat transfer member 8 is disposed between the other surface 6b of the heat generating component 6 and the phase change cooler 9, and contacts the other surface 6b of the heat generating component 6 and the phase change cooler 9. The heat transfer member 8 may be composed of, for example, heat dissipation grease or a heat dissipation sheet. It is preferable that the heat transfer member 8 is formed of a material with as high a thermal conductivity as possible. However, many heat transfer members with high thermal conductivity are formed of a hard material, which affects the reliability of the joint between the heat generating component 6 and the circuit board 4. It is preferable that the heat transfer member 8 of this embodiment is formed of a material with a level of hardness that does not affect the reliability of the joint between the heat generating component 6 and the circuit board 4. From the standpoint of reliability and thermal resistance, it is preferable that the heat transfer member 8 be made of a material that is deformable in response to thermal deformation of the heat-generating components 6 and the circuit board 4.

[0021] The phase change cooler 9 is a cooler that transports heat with a phase change of the refrigerant. The phase change cooler 9 is a cooler that includes an evaporator that removes heat from the heat-generating component 6 by changing the phase of the liquid refrigerant to a gas phase without using power, and a condenser that dissipates heat from the gas phase refrigerant into the air by changing the phase of the gas phase refrigerant to a liquid phase. The phase change cooler 9 may be configured, for example, by a vapor chamber or a heat pipe.

[0022] The phase change cooler 9 is provided in the housing 1. As shown in FIG. 2, the phase change cooler 9 is joined to the inner surface of the top plate portion 21 of the cover 2 of the housing 1. The phase change cooler 9 is disposed between the heat transfer member 8 in contact with the other surface 6b of the heat generating component 6 and the top plate portion 21, and is in contact with the heat transfer member 8 and the top plate portion 21. As shown in FIG. 1, the phase change cooler 9 is formed so as to extend from the heat generating component 6 mounted on the circuit board 4 toward the connector 5. The phase change cooler 9 is formed so as to extend from the other end 4b of the circuit board 4 in the direction along the circuit board 4 toward one end 4a. The phase change cooler 9 has one end 9a close to the connector 5 in the direction along the circuit board 4, and the other end 9b separated from the connector 5 in the direction along the circuit board 4. The other end 9b of the phase change cooler 9 can be the end close to the heat generating component 6. The phase change cooler 9 may be formed in a plate shape. The phase change cooler 9 removes heat from the heat generating component 6 via the heat transfer member 8, and diffuses the heat throughout the phase change cooler 9, and also transfers the heat to the top plate portion 21 for release to the outside.

[0023] In the in-vehicle electronic device 100 having the above-mentioned configuration, the following heat dissipation phenomenon occurs. The heat of the heat-generating component 6 is transferred to the phase-change cooler 9 via the heat transfer member 8, and then transferred to the liquid-phase refrigerant inside the other end 9b of the phase-change cooler 9. The liquid-phase refrigerant flows to one end 9a of the phase-change cooler 9 while changing into a gas phase. When the refrigerant that has changed into a gas phase reaches the one end 9a of the phase-change cooler 9, it dissipates heat and changes into a liquid phase. The refrigerant that has changed into a liquid phase flows to the other end 9b of the phase-change cooler 9 by capillary action. In this way, the refrigerant circulates between the other end 9b and the one end 9a with a phase change, so that the heat of the heat-generating component 6 is quickly diffused and released to the outside, and the temperature of the heat-generating component 6 is reduced.

[0024] The above heat dissipation phenomenon continues smoothly as long as the heat-generating component 6 generates heat, because the phase change cooler 9 is formed to extend from the heat-generating component 6 mounted on the circuit board 4 toward the connector 5. This is because the characteristics of the phase change cooler 9 and the characteristics of the temperature distribution on the circuit board 4 are utilized, as described in detail below.

[0025] The phase change cooler 9 is a heat sink in which a refrigerant is sealed inside, and the refrigerant repeats phase changes between liquid and gas phases due to minute temperature differences on the inner surface, diffusing heat over a wide area. The phase change cooler 9 has a thermal diffusion capacity that is orders of magnitude higher than, for example, a copper or aluminum heat sink. This high thermal diffusion capacity allows the phase change cooler 9 to quickly reduce the temperature of the heat-generating component 6. One of the important points for maintaining the high thermal diffusion capacity of the phase change cooler 9 is to maintain a state in which there is a temperature difference along the extension direction of the phase change cooler 9. In the case of an in-vehicle electronic device 100 equipped with a heat-generating component 6, when heat exceeding the heat capacity of the phase change cooler 9 is transferred to the phase change cooler 9, the temperature distribution of the entire phase change cooler 9 becomes uniform. Since the phase change cooler 9 diffuses heat by the phase change of the refrigerant due to minute temperature differences on the inner surface, if the temperature distribution of the entire phase change cooler 9 becomes uniform, the thermal diffusion capacity of the phase change cooler 9 decreases. It is therefore important that the phase change cooler 9 is configured to maintain a temperature difference along the direction in which the phase change cooler 9 extends.

[0026] On the other hand, in the circuit board 4 of the in-vehicle electronic device 100, electronic components 7 including a power supply circuit and the like are often mounted in a position close to the connector 5, and heat-generating components 6 such as a processor are often mounted in a position away from the connector 5. In addition, heat from the circuit board 4 is dissipated by a harness 51 connected to the connector 5. For these reasons, the temperature distribution of the circuit board 4 is often such that the vicinity of the connector 5 is low.

[0027] The phase change cooler 9 of the first embodiment is formed to extend from the heat generating component 6 mounted on the circuit board 4 toward the connector 5, so that a state with a temperature difference can be maintained along the extending direction of the phase change cooler 9. As a result, in the in-vehicle electronic device 100 of the first embodiment, the refrigerant of the phase change cooler 9 can be efficiently circulated between the other end 9b and the one end 9a, and the high heat diffusion capacity of the phase change cooler 9 can be maintained. Therefore, in the in-vehicle electronic device 100 of the first embodiment, the heat diffusion capacity of the phase change cooler 9 can be maximized, and high heat dissipation performance can be ensured.

[0028] In particular, the phase change cooler 9 of the first embodiment is formed so as to extend from the other end 4b of the circuit board 4 on which the heat-generating component 6 is mounted toward one end 4a of the circuit board 4 on which the connector 5 is mounted. That is, the phase change cooler 9 of the first embodiment can be formed long enough to reach both ends 4a, 4b of the circuit board 4. This allows the in-vehicle electronic device 100 of the first embodiment to increase the temperature difference along the extending direction of the phase change cooler 9, and further maintain the high heat diffusion ability of the phase change cooler 9. Therefore, the in-vehicle electronic device 100 of the first embodiment can further enhance the heat diffusion ability of the phase change cooler 9, and further ensure high heat dissipation performance.

[0029] [Embodiment 2] An in-vehicle electronic device 100 according to the second embodiment will be described with reference to Fig. 3. In the in-vehicle electronic device 100 according to the second embodiment, the description of the same configuration and operation as those of the previous embodiments will be omitted. FIG. 3 is an explanatory diagram of an in-vehicle electronic device 100 according to the second embodiment.

[0030] In the in-vehicle electronic device 100 of the second embodiment, heat from a plurality of heat generating components 6 is diffused by one phase change cooler 9. Specifically, the heat generating components 6 of the second embodiment are configured by a plurality of heat generating components 6 having different heat generation amounts. The plurality of heat generating components 6 include a maximum heat generating component having the largest heat generation amount and a minimum heat generating component having the smallest heat generation amount. The maximum heat generating component is mounted at a position farther away from the connector 5 than the minimum heat generating component in the direction along the circuit board 4. The heat transfer member 8 of the second embodiment is configured by a plurality of heat transfer members 8 that contact the other surface 6b of each of the plurality of heat generating components 6. The phase change cooler 9 of the second embodiment extends from the maximum heat generating component toward the minimum heat generating component.

[0031] In the example of FIG. 3, the heat of the multiple heat generating components 61-63 is diffused by the phase change cooler 91 on the right side of the figure. The heat generating components 61-63 have the following relationship of heat generation: heat generating component 61>heat generating component 62>heat generating component 63. Of the multiple heat generating components 61-63, the heat generating component 61 is the maximum heat generating component, and the heat generating component 63 is the minimum heat generating component. The heat generating component 61, which is the maximum heat generating component, is mounted at a position farthest from the connector 5. The heat generating component 62, which has the second largest heat generation amount after the heat generating component 61, is mounted at a position closer to the connector 5 than the heat generating component 61. The heat generating component 63, which is the minimum heat generating component, is mounted at a position closest to the connector 5. In other words, the multiple heat generating components 61-63 are arranged so that the heat generation amount increases in sequence with increasing distance from the connector 5. The phase change cooler 91 is formed to extend from the heat generating component 61, which is the maximum heat generating component, toward the heat generating component 63, which is the minimum heat generating component.

[0032] 3, heat from a plurality of heat generating components 64-65 is diffused by phase change cooler 92 on the left side of the figure. The magnitude relationship of the heat generation amounts among the heat generating components 64-65 is heat generating component 64 > heat generating component 65, and heat generating component 64, which is the maximum heat generating component, is mounted at a position furthest from connector 5. Phase change cooler 92 is formed to extend from heat generating component 64, which is the maximum heat generating component, toward heat generating component 65, which is the minimum heat generating component.

[0033] The refrigerant of phase change cooler 91 absorbs heat from heat generating component 61, which is the largest heat generating component mounted at the position farthest from connector 5, and then absorbs heat from heat generating component 62 → heat generating component 63, in that order, before flowing to one end 91a closer to connector 5. Similarly, the refrigerant of phase change cooler 92 absorbs heat from heat generating component 64, which is the largest heat generating component mounted at the position farthest from connector 5, and then absorbs heat from heat generating component 65, before flowing to one end 92a closer to connector 5.

[0034] Here, if the heat generation amounts of the multiple heat generating components 61-63 are not in the above-mentioned relationship in which the heat generation amounts increase with increasing distance from the connector 5, but are in the opposite relationship (heat generating component 61<heat generating component 62<heat generating component 63), the refrigerant of the phase change cooler 91 may not flow to one end 91a closer to the connector 5. In this embodiment, the multiple heat generating components 61-63 are arranged so that the heat generation amounts increase with increasing distance from the connector 5, so that the refrigerant of the phase change cooler 91 can flow to one end 92a closer to the connector 5 while removing heat from each of the multiple heat generating components 61-63. The same applies to the multiple heat generating components 64-65 and the phase change cooler 92.

[0035] In this way, the phase change cooler 9 of the second embodiment is provided in the housing 1 and is formed so as to extend from the maximum heat generating component to the minimum heat generating component included in the plurality of heat generating components 6. As a result, even if the in-vehicle electronic device 100 of the second embodiment includes a plurality of heat generating components 6 having different heat generating amounts, the heat diffusion capacity of the phase change cooler 9 can be maximized and the heat of each of the plurality of heat generating components 6 can be diffused by the minimum number of phase change coolers 9. Therefore, even if the in-vehicle electronic device 100 of the second embodiment includes a plurality of heat generating components 6 having different heat generating amounts, the heat diffusion capacity of the phase change cooler 9 can be maximized and high heat dissipation performance can be ensured.

[0036] [Embodiment 3] An in-vehicle electronic device 100 according to the third embodiment will be described with reference to Fig. 4. In the in-vehicle electronic device 100 according to the third embodiment, the description of the same configuration and operation as those of the previous embodiments will be omitted. 4 is an explanatory diagram of an in-vehicle electronic device 100 according to the third embodiment. Note that FIG. 4 corresponds to FIG.

[0037] In the in-vehicle electronic device 100 of the third embodiment, the phase change cooler 9 is provided integrally inside the housing 1. Specifically, the phase change cooler 9 of the third embodiment is provided integrally inside the top plate portion 21 of the cover 2. The phase change cooler 9 of the third embodiment may be made of a material having the same linear expansion coefficient as the cover 2, preferably the same material as the cover 2.

[0038] As a result, in the in-vehicle electronic device 100 of the third embodiment, there is no joint between the phase change cooler 9 and the housing 1. As a result, in the in-vehicle electronic device 100 of the third embodiment, it is possible to suppress a decrease in heat dissipation performance due to thermal resistance at the joint between the phase change cooler 9 and the housing 1. Compared to general-purpose or industrial electronic devices, the in-vehicle electronic device 100 is used in a harsh environment (particularly in terms of vibration, temperature, etc.), so it is not easy to ensure the mechanical reliability of the joint. In the in-vehicle electronic device 100 of the third embodiment, there is no joint between the phase change cooler 9 and the housing 1, so it is possible to improve the mechanical reliability compared to the case in which the phase change cooler 9 is joined to the housing 1 as in the first embodiment.

[0039] [Embodiment 4] An in-vehicle electronic device 100 according to the fourth embodiment will be described with reference to Figures 5 to 8. In the in-vehicle electronic device 100 according to the fourth embodiment, the description of the same configuration and operation as those of the previous embodiments will be omitted. FIG. 5 is a perspective view showing an external configuration of the in-vehicle electronic device 100 of the fourth embodiment. FIG. 6 is a perspective view showing a cross section of the in-vehicle electronic device 100 taken along the line B-B' shown in FIG. 5. FIG. 7 is an explanatory diagram of an arrangement structure of the cover 2 having the first top plate portion 21a and the second top plate portion 21b, the low-profile heat generating component 66, and the high-profile heat generating component 67. FIG. 8 is an explanatory diagram of an arrangement structure of the cover 2 not having the first top plate portion 21a and the second top plate portion 21b, the low-profile heat generating component 66, and the high-profile heat generating component 67. Note that hatching of the cross section is omitted in FIG. 6.

[0040] In the in-vehicle electronic device 100 of the fourth embodiment, the top plate portion 21 of the cover 2 may have an uneven shape. Specifically, the top plate portion 21 of the cover 2 of the fourth embodiment has a first top plate portion 21a separated from the circuit board 4 by a first distance D1, and a second top plate portion 21b separated from the circuit board 4 by a second distance D2 longer than the first distance D1. The phase change cooler 9 of the fourth embodiment is integrally provided inside the first top plate portion 21a and the second top plate portion 21b. As a result, in the in-vehicle electronic device 100 of the fourth embodiment, the length of the gap G between the heat-generating component 6 and the top plate portion 21 can be appropriately designed according to the height of the heat-generating component 6 from the circuit board 4. The height of the heat-generating component 6 from the circuit board 4 is the height of the heat-generating component 6 based on the surface of the circuit board 4 on which the heat-generating component 6 is mounted.

[0041] In the in-vehicle electronic device 100 of the fourth embodiment, which includes the cover 2 having such a first top plate portion 21a and a second top plate portion 21b, the heat generating component 6 may be configured by a plurality of heat generating components 6 having different heights from the circuit board 4, as shown in FIG. 7. The plurality of heat generating components 6 include a low-profile heat generating component 66 having a low height from the circuit board 4 and a high-profile heat generating component 67 having a high height from the circuit board 4. The low-profile heat generating component 66 is disposed between the first top plate portion 21a and the circuit board 4 in the thickness direction of the circuit board 4. The high-profile heat generating component 67 is disposed between the second top plate portion 21b and the circuit board 4 in the thickness direction of the circuit board 4. As a result, in the in-vehicle electronic device 100 of the fourth embodiment, the length of the gap G between each of the low-profile heat generating component 66 and the high-profile heat generating component 67 and the top plate portion 21 can be made appropriate, and an increase in the thermal resistance of these gaps G can be suppressed.

[0042] That is, as shown in FIG. 8, when the cover 2 does not have the first top plate portion 21a and the second top plate portion 21b, the gap G' between the low-profile heat generating component 66 and the top plate portion 21 must be filled by thickening the heat transfer member 8. This is because it is not easy to provide a heat dissipation pedestal on the cover 2 equipped with the phase change cooler 9. The lower the height of the low-profile heat generating component 66 from the circuit board 4, the longer the length of the gap G' and the thicker the heat transfer member 8. Since the thermal conductivity of the heat transfer member 8 is lower than that of the cover 2 and the phase change cooler 9, the longer the length of the gap G', the greater the thermal resistance of the gap G, as shown in the following formula. Therefore, in order to suppress the increase in the thermal resistance of the gap G, it is important to shorten the length of the gap G. Thermal resistance of gap G = length of gap G / (thermal conductivity of heat transfer member 8 × area)

[0043] In the in-vehicle electronic device 100 of the fourth embodiment, the cover 2 has the first top plate portion 21a and the second top plate portion 21b, and the length of the gap G between each of the low-profile heat-generating component 66 and the high-profile heat-generating component 67 and the top plate portion 21 can be set to an appropriate length. As a result, even if the in-vehicle electronic device 100 of the fourth embodiment includes a plurality of heat-generating components 6 that are different in height from the circuit board 4, the increase in the thermal resistance of the gap G can be suppressed, so that the heat diffusion capacity of the phase change cooler 9 can be maximized and the heat of each of the plurality of heat-generating components 6 can be diffused by the phase change cooler 9. Therefore, in the in-vehicle electronic device 100 of the fourth embodiment, even if the in-vehicle electronic device 100 includes a plurality of heat-generating components 6 that are different in height from the circuit board 4, the heat diffusion capacity of the phase change cooler 9 can be maximized and high heat dissipation performance can be ensured.

[0044] [Embodiment 5] 9 and 10, an in-vehicle electronic device 100 according to the fifth embodiment will be described. In the in-vehicle electronic device 100 according to the fifth embodiment, the description of the same configuration and operation as those of the previous embodiments will be omitted. Fig. 9 is an explanatory diagram of an example of the in-vehicle electronic device 100 of embodiment 5. Fig. 10 is an explanatory diagram of another example of the in-vehicle electronic device 100 of embodiment 5. Each of Figs. 9 and 10 corresponds to Fig. 2.

[0045] In the in-vehicle electronic device 100 of the fifth embodiment, the circuit board 4 is a circuit board that can be mounted on both sides. The connector 5 is an electronic component that is higher from the circuit board 4 than the heat-generating component 6. The heat-generating component 6 is mounted on a surface 4d of the circuit board 4 opposite to the surface 4c on which the connector 5 is mounted. The phase change cooler 9 is provided on a top panel 21 of the cover 2 that faces the surface 4d of the circuit board 4 on which the heat-generating component 6 is mounted.

[0046] Furthermore, the in-vehicle electronic device 100 of the fifth embodiment may include a low-profile electronic component 71 and a high-profile electronic component 72 as electronic components 7 mounted on the circuit board 4 other than the connector 5 and the heat-generating component 6. The low-profile electronic component 71 is an electronic component 7 whose height from the circuit board 4 is equal to or smaller than that of the heat-generating component 6. The low-profile electronic component 71 is mounted on the surface 4d of the circuit board 4 on which the heat-generating component 6 is mounted. The high-profile electronic component 72 is an electronic component 7 whose height from the circuit board 4 is higher than that of the heat-generating component 6. The high-profile electronic component 72 is mounted on the surface 4c of the circuit board 4 on which the connector 5 is mounted. The high-profile electronic component 72 is, for example, an aluminum electrolytic capacitor.

[0047] With this configuration, in the cover 2 of the fifth embodiment, as shown in Figs. 1 and 2, it is not necessary to form the top plate 21 in a stepped shape according to the difference in height between the heat generating component 6 and the connector 5 from the circuit board 4. That is, in the cover 2 of the fifth embodiment, as shown in Fig. 9, the top plate 21 can be formed in a flat plate shape from the second side plate 22b over the heat generating component 6 and the connector 5 to the first side plate 22a. As a result, in the in-vehicle electronic device 100 of the fifth embodiment, the phase change cooler 9 extending from the heat generating component 6 toward the connector 5 can be expanded along the direction in which the phase change cooler 9 extends. For example, as shown in Fig. 9, the phase change cooler 9 can be expanded so that the distance L1 from the phase change cooler 9 to the outer surface of the first side plate 22a is as short as possible. By expanding the phase change cooler 9 along this direction, for example, as shown in Fig. 10, the heat generating component 6 can be mounted in a position close to the end face so that the distance L2 from the heat generating component 6 to the end face on the other end 4b side of the circuit board 4 is as short as possible. Therefore, in the in-vehicle electronic device 100 of the fifth embodiment, the area of the phase change cooler 9 can be increased, and therefore the heat dissipation area can be increased. Furthermore, in the in-vehicle electronic device 100 of the fifth embodiment, the temperature difference can be increased along the extending direction of the phase change cooler 9, and the high heat diffusion ability of the phase change cooler 9 can be further maintained. Therefore, in the in-vehicle electronic device 100 of the fifth embodiment, the heat diffusion ability of the phase change cooler 9 can be further enhanced, and high heat dissipation performance can be further ensured.

[0048] In the in-vehicle electronic device 100 of embodiments 4 and 5, the phase change cooler 9 is integrally provided inside the top plate portion 21 of the cover 2, but as in embodiment 1, the phase change cooler 9 may be joined to the inner surface of the top plate portion 21.

[0049] [Embodiment 6] An in-vehicle electronic device 100 according to the sixth embodiment will be described with reference to Fig. 11. In the in-vehicle electronic device 100 according to the sixth embodiment, the description of the same configuration and operation as those of the previous embodiments will be omitted. 11 is an explanatory diagram of an in-vehicle electronic device 100 according to embodiment 6. Note that FIG. 11 corresponds to FIG.

[0050] In the in-vehicle electronic device 100 of the sixth embodiment, the circuit board 4 is a circuit board that can be mounted on both sides. The circuit board 4 includes thermal vias 41 that penetrate the inside of the area where the heat-generating component 6 is mounted in the thickness direction of the circuit board 4. The phase change cooler 9 is composed of a first phase change cooler 93 and a second phase change cooler 94. Each of the first phase change cooler 93 and the second phase change cooler 94 is formed to extend from the heat-generating component 6 mounted on the circuit board 4 toward the connector 5.

[0051] The first phase change cooler 93 is a phase change cooler 9 provided in the housing 1. For example, the first phase change cooler 93 may be provided on the top plate portion 21 of the cover 2 facing the surface 4d of the circuit board 4 on which the heat generating component 6 is mounted, as in the fifth embodiment. The second phase change cooler 94 is provided on the surface 4c of the circuit board 4 opposite the surface 4d of the circuit board 4 on which the heat generating component 6 is mounted, and contacts the thermal vias 41. For example, the second phase change cooler 94 may be bonded to the surface 4c of the circuit board 4 so as to cover the thermal vias 41. The second phase change cooler 94 and the surface 4c of the circuit board 4 may be bonded using lead-free solder, a conductive adhesive, or the like.

[0052] In the in-vehicle electronic device 100 of the sixth embodiment, similarly to the fifth embodiment, the heat generating component 6 may be mounted on the surface 4d of the circuit board 4 opposite to the surface 4c on which the connector 5 is mounted.

[0053] With this configuration, in the in-vehicle electronic device 100 of the sixth embodiment, the first phase change cooler 93 can diffuse the heat of the heat-generating component 6, similar to the fifth embodiment. Furthermore, in the in-vehicle electronic device 100 of the sixth embodiment, the second phase change cooler 94 can diffuse the heat transferred from the heat-generating component 6 to the circuit board 4, similar to the first phase change cooler 93. Therefore, in the in-vehicle electronic device 100 of the sixth embodiment, the heat dissipation performance can be significantly improved compared to the fifth embodiment.

[0054] In the in-vehicle electronic device 100 of embodiment 6, the first phase change cooler 93 is integrally provided inside the top plate portion 21 of the cover 2, but as in embodiment 1, the first phase change cooler 93 may be joined to the inner surface of the top plate portion 21.

[0055] [Embodiment 7] 12 and 13, the in-vehicle electronic device 100 of the seventh embodiment will be described. In the in-vehicle electronic device 100 of the seventh embodiment, the description of the same configuration and operation as those of the previous embodiments will be omitted. Fig. 12 is an explanatory diagram of an example of the in-vehicle electronic device 100 of the embodiment 7. Fig. 13 is an explanatory diagram of another example of the in-vehicle electronic device 100 of the embodiment 7. Each of Fig. 12 and Fig. 13 corresponds to Fig. 2.

[0056] In the in-vehicle electronic device 100 of the seventh embodiment, the phase change cooler 9 is not provided in the housing 1 including the cover 2, but only in the circuit board 4. Specifically, in the in-vehicle electronic device 100 of the seventh embodiment, the circuit board 4 is a circuit board that can be mounted on both sides. The circuit board 4 includes a thermal via 41 that penetrates the inside of the area where the heat-generating component 6 is mounted in the thickness direction of the circuit board 4. The phase change cooler 9 is provided on a surface 4c of the circuit board 4 opposite to the surface 4d of the circuit board 4 on which the heat-generating component 6 is mounted, and is in contact with the thermal via 41. The phase change cooler 9 is formed so as to extend from the heat-generating component 6 mounted on the circuit board 4 toward the connector 5.

[0057] 12, the in-vehicle electronic device 100 of the seventh embodiment may have the heat-generating component 6 mounted on a surface 4d of the circuit board 4 opposite to the surface 4c on which the connector 5 is mounted. The heat-generating component 6 may be in contact with the case 3 via a heat transfer member 8.

[0058] 13, the in-vehicle electronic device 100 of the seventh embodiment may have the heat-generating component 6 mounted on the surface 4c of the circuit board 4 on which the connector 5 is mounted. The heat-generating component 6 may be in contact with the top plate portion 21 of the cover 2 via the heat transfer member 8.

[0059] With this configuration, in the in-vehicle electronic device 100 of embodiment 7, even if it is not possible to provide a phase change cooler 9 in the housing 1 including the cover 2, the phase change cooler 9 can be introduced, and high heat dissipation performance can be ensured by utilizing the thermal diffusion ability of the phase change cooler 9.

[0060] [others] The present invention is not limited to the above-described embodiments, and includes various modified examples. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the configurations described. In addition, it is possible to replace a part of the configuration of a certain embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of a certain embodiment. In addition, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0061] Reference Signs List 1...housing, 2...cover, 21a...first top plate portion, 21b...second top plate portion, 4...circuit board, 41...thermal via, 5...connector, 6...heat generating component, 8...heat transfer member, 9...phase change cooler, 93...first phase change cooler, 94...second phase change cooler, 100...electronic device for vehicle

Claims

1. a heat generating component having one surface mounted on a circuit board and another surface located on the opposite side to the one surface in a thickness direction of the circuit board; a connector mounted on the circuit board and connected to an external device; a housing that houses the circuit board on which the heat generating component and the connector are mounted; a phase change cooler extending from the heat generating component mounted on the circuit board toward the connector and transporting heat by causing a phase change of a refrigerant; a heat transfer member in contact with the other surface of the heat generating component and with a housing in which the phase change cooler is provided or with the phase change cooler.

1. An in-vehicle electronic device comprising:

2. The connector is mounted on at least one end of the circuit board, the heat generating component is mounted on at least the other end of the circuit board, The phase change cooler is provided in the housing and extends from the other end toward the one end.