Electronic control unit

Abstract

To provide a technology that can improve the heat dissipation and watertightness of electronic control devices, and that is also easy to manufacture. [Solution] The electronic control device houses a circuit board 19 on which heat-generating components 17 are mounted in the internal space NK of the housing 3. The housing 3's case 7 comprises a resin case body 33 and a metal heat sink member 35 integrally formed with the case body 33. The heat sink member 35 is configured so as not to be exposed to the outside of the housing 3 and comprises a heat receiving portion 37 and a heat dissipation portion 39 integrally formed with the heat receiving portion 33. The heat receiving portion 37 is exposed to the internal space NK and is positioned on the circuit board 19 side so as to be able to receive heat generated from the heat-generating components 17. The heat dissipation portion 39 has a shape that protrudes toward the outside of the housing 3, and the outer surface of the protruding portion is integrally covered by the resin case body 33 so as not to be exposed to the outside of the housing 3.

Description

Technical Field

[0001] The present disclosure relates to a technique for improving the heat dissipation and waterproof performance of an electronic control device.

Background Art

[0002] In recent years, as in-vehicle electronic control devices have become smaller and have higher heat generation, a structure that can efficiently dissipate heat has been required. In addition, as a housing for an electronic control device, a resin housing is known. Although it has the advantages of being inexpensive and lightweight compared to a metal housing, it tends to have inferior heat dissipation performance. This is because the thermal conductivity of the resin is lower than that of the metal, and heat released from heat-generating components such as heat-generating elements arranged inside the housing is difficult to move outside the housing.

[0003] As a countermeasure against this, a resin housing with a metal part inserted in the heat transfer path has been proposed (see, for example, Patent Document 1). Also, in such a housing, since the emissivity of the metal member is low as it is (that is, since the emissivity is low on the white surface of the metal), it is conceivable to apply a black paint to the surface of the metal member in order to increase the emissivity.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, as a result of the inventors' detailed examination, the following problems were found in the conventional technology. In the conventional technology described above, ensuring watertightness at the interface between the metal component and the resin housing is not easy, resulting in insufficient waterproofing. Therefore, there is a problem in that it is difficult to use in environments where waterproofing is required. Furthermore, if processing such as painting is required, the number of work steps increases, potentially leading to higher manufacturing costs.

[0006] One aspect of this disclosure is to provide a technology that can improve the heat dissipation and watertightness of electronic control devices and that is also easy to manufacture. [Means for solving the problem]

[0007] One aspect of this disclosure relates to an electronic control device (1) in which a circuit board (19) on which a heat-generating component (17) is mounted is housed in the internal space (NK) of a housing (3). The housing of the electronic control unit comprises a resin housing body (13) and a metal heat sink member (35) integrally formed with the housing body. The heat sink member is configured so as not to be exposed to the outside of the housing and comprises a heat receiving section (37) and a heat dissipation section (39) integrally formed with the heat receiving section.

[0008] The heat receiving section is exposed to the internal space and is positioned on the substrate side so as to be able to receive heat generated from heat-generating components. The heat dissipation section has a shape that protrudes outward from the housing, and the outer surface of the protruding part is integrally covered by the resin housing body so as not to be exposed to the outside of the housing.

[0009] In this disclosure, such a configuration can improve the heat dissipation and watertightness (and therefore, waterproofness) of the electronic control unit. Specifically, the housing of the electronic control unit comprises a resin housing body and a metal heat sink component. The heat receiving portion of the heat sink component can effectively receive heat generated from heat-generating components. The heat received by the heat receiving portion is then transferred to the heat dissipation portion. Since the heat dissipation portion protrudes outward from the housing, heat can be efficiently dissipated from the heat dissipation portion to the outside of the housing. Furthermore, the outer surface of the protruding portion of the heat dissipation portion is integrally covered by the resin housing body, resulting in higher watertightness (and therefore waterproofness) compared to cases where this is not the case.

[0010] Furthermore, if the configuration of the present disclosure is used, for example, the housing of the electronic control device (i.e., a housing in which a resin housing body and a heat sink member are integrally formed) can be easily manufactured (i.e., by a simple manufacturing process) by insert molding.

[0011] Furthermore, the reference numerals in parentheses in this section and in the claims indicate a correspondence with the specific means described later in the embodiments, and do not limit the technical scope of this disclosure. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view showing the electronic control device of the first embodiment. [Figure 2] This is a cross-sectional view showing a part of the electronic control device of the first embodiment, broken off (a cross-sectional view showing section AA in Figure 1). [Figure 3] This is a perspective view showing the heat sink member of the first embodiment. [Figure 4] This is a perspective view showing the electronic control device of the second embodiment. [Figure 5] Figure 5A is a cross-sectional view showing a part of the electronic control device of the second embodiment in a broken section (a cross-sectional view showing the BB section in Figure 4), and Figure 5B is a perspective view showing the heat sink member of the second embodiment. [Figure 6] This is a cross-sectional view (cross-sectional view in the YZ plane) showing a part of the electronic control device of the third embodiment, with the components cut away. [Figure 7]It is a cross-sectional view (cross-sectional view in the YZ plane) showing a part of another electronic control device according to the third embodiment, with some parts broken away.

Mode for Carrying Out the Invention

[0013] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. First Embodiment] In this first embodiment, an electronic control device mounted on a vehicle (for example, an automobile) will be described as an example.

[0014] [1-1. Configuration of the Electronic Control Device] As shown in FIG. 1, the electronic control device 1 includes a housing 3 which is a container for accommodating various components, and a connector 5 fixed to the housing 3.

[0015] Hereinafter, the description will be made using the XYZ orthogonal coordinates. The + side in the X-axis direction is the front side, and the - side is the rear side. The + side in the Y-axis direction is the right side, and the - side is the left side. The + side in the Z-axis direction is the upper side, and the - side is the lower side.

[0016] The outer shape of the electronic control device 1 (that is, the outer shape of the housing 3) is, for example, substantially rectangular in a plan view seen from the Z-axis direction, and is in the shape of a substantially rectangular parallelepiped box. Note that the surface of the housing 3 has irregularities.

[0017] The housing 3 includes a box-shaped case 7 and a cover 9 that covers the opening on the lower side of the case 7. As will be described later, as the material constituting the case 7 and the cover 9, resin or the like can be adopted, but as the cover 9, a metal such as iron or an aluminum alloy can also be adopted.

[0018] The case 7 is a box-shaped container with openings on the lower side and the rear side, and includes a case front portion 11 having irregularities and a case rear portion 13 that is thicker than the case front portion 11 at the rear side of the case front portion 11. Note that an overhanging portion 15 is provided so as to surround the outer periphery of the lower part of the case 7.

[0019] Inside the front section 11 of the case, a circuit board 19 on which heat-generating components 17 such as electronic components are mounted is arranged (see, for example, Figure 2), and a part of the connector 5 is fitted into the rear side of the rear section 13 of the case so as to seal the rear opening of the case 7 with water. Examples of electronic components include well-known computers that perform various calculations and processes (e.g., microcomputers) and their components (e.g., CPUs).

[0020] The cover 9 is a plate-like member that is roughly rectangular in shape when viewed from above, and its perimeter extends to a position similar to that of the protruding portion 15 of the case 7. Furthermore, the case 7 and the cover 9 are integrally fixed together by fixing members 18 such as screws, which are positioned on the protruding portion 15 of the case 7 and the outer circumference of the cover 9. The protruding portion 15 of the case 7 is provided with a mounting portion 21 to which a bracket (not shown) for fixing the electronic control unit 1 to the mounting object is attached.

[0021] <Case> Next, we will explain Case 7 in more detail. As shown in Figure 1, the front part 11 of the case is roughly rectangular in plan view, and a flat section 25 is provided on its upper surface 23. A well-known breathing filter (i.e., a breathable waterproof filter) 27 is provided on the flat section 25, but the breathing filter 27 may be omitted.

[0022] Multiple (for example, four) fin-shaped protrusions 31 are erected perpendicularly to the flat portion 25 of the front part 11 of the case. The protrusions 31 are plate-like with a certain thickness and have a rectangular shape when viewed from the Y-axis direction. As will be described later, the protrusions 31 are molded integrally with the case 7 during the manufacturing process.

[0023] As shown in Figure 2, the case 7 comprises a resin case body 33 and a metal heat sink member 35 that is integrally formed with the case body 33. As the resin constituting the case body 33, PBT resin or the like can be used, but as will be described later, when manufacturing a case body 33 with a protruding portion 31, a resin with excellent fluidity is preferable. For example, as the PBT resin, highly fluid Duranex® SF3300 can be used. Alternatively, LCP resin or the like, which also has excellent fluidity, may be used. Note that PBT refers to polybutylene terephthalate, and LCP refers to liquid crystal polymer.

[0024] Furthermore, the resin color can be darker than the color of the metal constituting the heat sink component 35, such as black or dark gray. This increases the emissivity on the surface of the case body 33.

[0025] Various metals with superior thermal conductivity than the resins mentioned above can be used as the metal constituting the heat sink component 35. For example, aluminum alloys can be used. As shown in Figures 2 and 3, the heat sink member 35 comprises a plate-shaped heat receiving section 37 and a plurality (for example, four) of plate-shaped heat dissipation sections 39 provided perpendicular to the heat receiving section 37. Specifically, the heat receiving section 37 is a rectangular plate when viewed from its own thickness direction (Z-axis direction). The heat dissipation section 39 is a plurality of fin-shaped plate materials erected perpendicular to the heat receiving section 37 on one side (upper side) of the heat receiving section 37 in the thickness direction (upper side). The heat dissipation section 39 is rectangular when viewed from its own thickness direction (Y-axis direction), and each heat dissipation section 39 is positioned in the ZX plane. They are arranged parallel to each other. The heat sink member 35 is manufactured integrally, for example by casting, and the heat receiving section 37 and the heat dissipation section 39 are a single integrated unit.

[0026] As shown in Figure 2, the heat sink member 35 is configured so as not to be exposed to the outside of the case 7 (specifically, the resin case body 33) that constitutes the housing 3. Specifically, the heat dissipation portion 39 has a shape that protrudes outward from the case 7 (upward in Figure 2), and the outer surface of the protruding portion is integrally covered by a resin case body 33 so as not to be exposed to the outside of the case 7. The portion of the case body 33 that covers the portion of the heat dissipation portion 39 that protrudes outward is called the covering layer 41, and the aforementioned protruding portion 31 is composed of the heat dissipation portion 39 of the heat sink member 35 and the covering layer 41 that covers the heat dissipation portion 39.

[0027] The thickness T1 of the coating layer 41 is configured to be thinner than the thickness T2 of the other parts that make up the case body 33. For example, the thickness T1 of the coating layer 41 can be in the range of 0.2 mm to 0.5 mm.

[0028] Furthermore, if the thickness T1 of the coating layer 41 differs depending on the location, the average thickness can be used as the thickness T1 of the coating layer 41. Also, if the thickness T2 of the case body 33 other than the coating layer 41 differs depending on the location, the average thickness can be used.

[0029] Furthermore, the heat receiving section 37 is exposed to the internal space NK within the housing 3 and is positioned on the substrate 19 side so as to be able to receive heat generated from the heat-generating component 17. In other words, the heat receiving section 37 is exposed to the internal space NK on the substrate 19 side.

[0030] Furthermore, the heat receiving section 37 is positioned such that, when each heat-generating component 17 is projected onto the substrate 19 in the thickness direction (more specifically, the upper side in the Z-axis direction), at least a portion of the projected area (i.e., the projected region) overlaps with the heat receiving section 37.

[0031] Furthermore, each heat-generating component 17 is mounted on the substrate 19 on the side (upper side) of the heat sink member 35, and a thermal conductive material 43 is placed so as to be in contact with the heat receiving portion 37 of the heat sink member 35 and each heat-generating component 17. In other words, a thermal conductive material 43 is placed between the heat receiving portion 37 and each heat-generating component 17.

[0032] As the thermal conductive material 43, a material capable of conducting heat generated in the heat-generating component 17, such as a well-known gel-like thermal conductive material 43, can be used. Specifically, examples of thermal conductive materials 43 include silicone resin, epoxy resin, acrylic resin, etc. Furthermore, these resins may contain highly thermally conductive fillers such as alumina particles.

[0033] <Case manufacturing method> Now, let's explain the manufacturing method for Case 7. A heat sink member 35 is placed inside a mold (not shown), and the resin constituting the case body 33 is filled into the mold (i.e., by insert molding) to manufacture a case 7 in which the case body 33 and the heat sink member 35 are integrated.

[0034] [1-2. Effects] According to this first embodiment, the following effects can be obtained. (1a) This first embodiment can improve the heat dissipation and watertightness (and therefore, waterproofness) of the electronic control device 1.

[0035] Specifically, the housing 3 of the electronic control unit 1 comprises a resin case body 33 and a metal heat sink member 35, and the heat receiving portion 37 of the heat sink member 35 is connected to the heat-generating component 17. The heat generated can be received efficiently. The heat received by the heat receiving section 37 is transferred to the heat dissipation section 39, and since the heat dissipation section 39 is shaped to protrude to the outside of the housing 3 (more specifically, the case body 33), heat can be efficiently dissipated from the heat dissipation section 39 to the outside of the housing 3. Furthermore, since the outer surface of the protruding part of the heat dissipation section 39 is integrally covered by the resin case body 33, it has higher watertightness (and therefore waterproofness) compared to a case where this is not the case.

[0036] Furthermore, in the configuration of this first embodiment, for example, the case 7 of the electronic control device 1 (more specifically, the case 7 in which the case body 33 and the heat sink member 35 are integrally formed) can be easily manufactured (i.e., by a simple manufacturing process) by insert molding.

[0037] (1b) In this first embodiment, the thickness T1 of the covering layer 41 which constitutes a part of the case body 33 that covers the protruding portion of the heat dissipation section 39 is thinner than the thickness T2 of the other parts that constitute the case body 33. Therefore, it is possible to efficiently dissipate heat from the heat dissipation section 39 to the outside of the housing 3.

[0038] (1c) In this first embodiment, when the heat-generating component 17 is projected in the thickness direction of the substrate 19, the heat sink member 35 is arranged in the projected area, so that the heat generated by the heat-generating component 17 can be efficiently transferred to the heat sink member 35.

[0039] (1d) In this first embodiment, the heat-generating component 17 is mounted on the heat sink member 35 side of the substrate 19, and the heat conductive material 43 is arranged so as to be in contact with the heat receiving portion 37 of the heat sink member 35 and the heat-generating component 17, so that the heat generated by the heat-generating component 17 can be efficiently transferred to the heat sink member 35 via the heat conductive material 43.

[0040] (1e) In this first embodiment, the heat dissipation section 39 has a plate shape, so heat can be dissipated efficiently. (1f) In this first embodiment, the heat sink member 35 includes a flat heat receiving section 37 and a heat dissipation section 39 erected on one surface in the thickness direction of the heat receiving section 37. Therefore, heat from the heat-generating component 17 can be efficiently transferred to the heat receiving section 37, and the heat received by the heat receiving section 37 can be efficiently dissipated from the heat dissipation section 39.

[0041] [1-3. Correspondence] Next, the relationship between this first embodiment and this disclosure will be described. The electronic control unit 1 corresponds to the electronic control unit, the housing 3 corresponds to the housing, the internal space NK corresponds to the internal space, the heat-generating component 17 corresponds to the heat-generating component, the circuit board 19 corresponds to the circuit board, the case body 33 corresponds to the housing body, the heat sink member 35 corresponds to the heat sink member, the heat receiving section 37 corresponds to the heat receiving section, the heat dissipation section 39 corresponds to the heat dissipation section, the thermal conductive material 43 corresponds to the thermal conductive material, and the coating layer 41 corresponds to the coating layer.

[0042] [2. Second Embodiment] Since the basic configuration of the second embodiment is the same as that of the first embodiment, the differences from the first embodiment will be described below. Note that components with the same names have the same functions as in the first embodiment, and the same reference numerals as in the first embodiment indicate the same components; please refer to the preceding description.

[0043] As shown in Figure 4, the electronic control unit 51 of this second embodiment is equipped with a housing 53 similar to that of the first embodiment, and the housing 53 is equipped with a case 55 and a cover 57 similar to those of the first embodiment.

[0044] As shown in Figure 5A, the case 55 comprises a case body 59 and a heat sink member 61, and its material is the same as in the first embodiment. In this second embodiment, as shown in Figures 4 and 5, the shape of the protrusion 63 provided on the case body 59 and the shape of the heat sink member 61 arranged inside the protrusion 63 differ from those of the first embodiment.

[0045] Specifically, as shown in Figure 5B, the heat sink member 61 comprises a disc-shaped heat receiving section 65 and a pin-shaped (more specifically, cylindrical) heat dissipation section 67 provided on one side of the heat receiving section 65 in the thickness direction. The heat dissipation section 67 is erected coaxially and perpendicularly to the heat receiving section 65.

[0046] As shown in Figure 5A, the surface of the portion of the heat dissipation section 67 that protrudes outward from the case body 59 is provided with a coating layer 69 integrated with the case body 59, similar to the first embodiment, so that the heat dissipation section 67 is not exposed from the case body 59. Also, similar to the first embodiment, the thickness T1 of the coating layer 69 is thinner than the thickness T2 of the case body 59 other than the coating layer 69. Furthermore, due to the above configuration, the shape of the protruding portion 63 is cylindrical.

[0047] Furthermore, similar to the first embodiment, a heat conductive material 43 is placed between the heat-generating component 17 mounted on the upper surface of the substrate 19 and the heat receiving section 65. As shown in Figure 4, the heat sink member 61 of the protruding portion 63 that protrudes from the case body 59 may have one heat receiving portion 65 with one heat dissipation portion 67, or it may have multiple (for example, three) heat dissipation portions 67 on one heat receiving portion (for example, a long heat receiving portion) 65.

[0048] This second embodiment provides the same effects as the first embodiment. [3. Third Embodiment] Since the basic configuration of the third embodiment is the same as that of the first embodiment, the differences from the first embodiment will be described below. Note that components with the same names have the same functions as in the first embodiment, and the same reference numerals as in the first embodiment indicate the same components; please refer to the preceding description.

[0049] As shown in Figure 6, in this third embodiment, the heat-generating component 17 is mounted on one side of the substrate 19, that is, the side opposite to the heat sink member 35 (back surface: bottom surface). The thermal conductive material 43 is positioned so as to contact the heat receiving portion 37 of the heat sink member 35 with the surface (top surface) opposite to the mounting side of the heat-generating component 17. The area of ​​the top surface that the thermal conductive material 43 contacts is the projection area when the heat-generating component 17 is projected in the thickness direction of the substrate 19.

[0050] This third embodiment provides the same effects as the first embodiment. Furthermore, as shown in Figure 7, if heat-generating components 17 are mounted on both sides of the substrate 19 (i.e., the top and bottom surfaces), a configuration combining the configuration of the first embodiment and the configuration of the second embodiment can be adopted.

[0051] In other words, if the heat-generating component 17 is located on the upper surface of the substrate 19, the heat conductive material 43 may be placed between the heat-generating component 17 and the heat-receiving portion 37 of the heat sink member 35. Alternatively, if the heat-generating component 17 is located on the lower surface of the substrate 19, the heat conductive material 43 may be placed between the surface (upper surface) opposite to the mounting side of the heat-generating component 17 and the heat-receiving portion 37.

[0052] [4. Other Embodiments] While embodiments of this disclosure have been described above, it goes without saying that this disclosure is not limited to the embodiments described above and can take various forms.

[0053] (4a) In this disclosure, the shape of the heat dissipation section is not limited to fin shape or pin shape, but can be of various shapes. Regarding the shape of the fin, it is not limited to rectangles, but can be triangular, polygonal, semicircular, etc. Regarding the shape of the pin, it is not limited to cylindrical shapes, but can be rectangular tube shapes, columnar shapes, etc. Furthermore, this disclosure can be applied not only to vehicles, but also to various equipment such as electronic devices for ships and aircraft.

[0054] (4b) Multiple functions of one component in each of the above embodiments may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Furthermore, some of the configurations of each of the above embodiments may be omitted. Furthermore, at least some of the configurations of each of the above embodiments may be added to or replaced with the configurations of other embodiments. [Explanation of symbols]

[0055] 1, 53…Electronic control unit, 3, 53…Enclosure, 7, 55…Case, 17…Heat-generating component, 19…Circuit board, 33, 59…Case body, 35, 61…Heat sink component, 37, 65…Heat receiving section, 39, 67…Heat dissipation section, 41, 69…Coating layer, 43…Thermal conductive material

Claims

1. An electronic control device (1) having a circuit board (19) on which a heat-generating component (17) is mounted housed in the internal space (NK) of a housing (3), The housing comprises a resin housing body (13) and a metal heat sink member (35) integrally formed with the housing body. The heat sink member is configured so as not to be exposed to the outside of the housing and comprises a heat receiving portion (37) and a heat dissipation portion (39) which is integrally formed with the heat receiving portion. The heat receiving portion is exposed to the internal space and is positioned on the substrate side so as to be able to receive heat generated from the heat-generating component. The heat dissipation portion has a shape that protrudes outward from the housing, and the outer surface of the protruding portion is integrally covered by the resin housing body so as not to be exposed to the outside of the housing. Electronic control unit.

2. The electronic control device according to claim 1, The thickness of the covering layer (41) that forms part of the housing body covering the protruding portion of the heat dissipation section is configured to be thinner than the thickness of the other parts of the housing body. Electronic control unit.

3. The electronic control device according to claim 1, When the heat-generating component is projected in the thickness direction of the substrate, the heat sink member is arranged in the projection region. Electronic control unit.

4. The electronic control device according to claim 1, The heat-generating component is mounted on the substrate on the heat sink member side. A heat conductive material (43) is arranged so as to contact the heat receiving portion of the heat sink member and the heat generating component. Electronic control unit.

5. The electronic control device according to claim 1, The heat-generating component is mounted on the substrate on the side opposite to the heat sink member. A heat conductive material is arranged so as to contact the heat receiving portion of the heat sink member with the surface of the substrate opposite to the side on which the heat-generating component is mounted. Electronic control unit.

6. The electronic control device according to claim 1, The shape of the heat dissipation section is plate-shaped. Electronic control unit.

7. The electronic control device according to claim 1, The shape of the heat dissipation part is pin-shaped. Electronic control unit.

8. The electronic control device according to claim 1, The heat sink member comprises a flat heat receiving portion and a heat dissipation portion erected on one surface in the thickness direction of the heat receiving portion. Electronic control unit.

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