Electronic control device

Abstract

An electronic control device includes a circuit board on which an electronic component can be mounted, a case in which the circuit board on which the electronic component is mounted is housed, a plurality of heat dissipation fins protruding outward from an outer surface portion, which is an outer surface of the case, an outer thick portion, an inner thick portion, and a thin portion connecting the outer thick portion and the inner thick portion. The outer thick portion is formed at a position facing an electronic component mounted on the circuit board in the outer surface portion of the housing, and protrudes outward from the outer surface portion. The inner thick wall portion is formed at a position facing an electronic component mounted on the circuit board in an inner surface portion of the housing, and protrudes from the inner surface portion toward the electronic component. In addition, the thickness of a thick wall part composed of the outer thick wall part, the inner thick wall part and the thin wall part is larger than the average thickness of the shell. In addition, heat dissipation fins are formed on the outer thick wall part.

Description

Technical Field

[0001] This invention relates to electronic control devices. Background Technology

[0002] Motor vehicles are equipped with electronic control devices that contain electronic components for controlling the vehicle. To dissipate heat from the electronic components, the electronic control devices have a heat dissipation structure that thermally connects heat dissipation modules and heat dissipation components.

[0003] As a technology for heat dissipation of electronic components, for example, there is the technology described in Patent Document 1. Patent Document 1 describes an electronic control device 1 having a heat transfer material thermally coupled to the electronic component and disposed between the electronic component and a heat dissipation section, and an intermediate portion disposed between a region of the electronic component not thermally coupled to the heat transfer material and the heat transfer material. Furthermore, Patent Document 1 describes a device comprising an electronic component and a heat transfer component thermally coupled to the heat transfer material.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-202329 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] In recent years, the demand for Advanced Driver Assistance Systems (ADAS) and Autonomous Driving Systems (AD) has increased, and the development of autonomous driving technology for motor vehicles is accelerating. Furthermore, with the improvement of electronic control device functionality, the heat generated by the onboard electronic components is also increasing. As a result, the technology described in Patent Document 1 suffers from the problem of insufficient heat dissipation from the electronic components that generate increased heat.

[0009] The purpose of this invention is to address the above-mentioned problems and provide an electronic control device that can improve heat dissipation.

[0010] Technical solutions to the problem

[0011] To solve the aforementioned problems and achieve the objective, the electronic control device includes a circuit board capable of mounting electronic components, a housing housing the circuit board with the mounted electronic components, multiple heat dissipation fins protruding outward from the outer surface (outer part) of the housing, an outer thick-walled portion, an inner thick-walled portion, and a thin-walled portion connecting the outer thick-walled portion and the inner thick-walled portion. The outer thick-walled portion is formed in the outer surface of the housing at a position opposite to the electronic components mounted on the circuit board, and protrudes outward from the outer surface. The inner thick-walled portion is formed in the inner surface of the housing at a position opposite to the electronic components mounted on the circuit board, and protrudes towards the electronic components from the inner surface. Furthermore, the thickness of the thick-walled portion, composed of the outer thick-walled portion, the inner thick-walled portion, and the thin-walled portion, is made thicker than the average thickness of the housing. Additionally, heat dissipation fins are formed on the outer thick-walled portion.

[0012] Invention Effects

[0013] The electronic control device based on the above structure can improve heat dissipation. Attached Figure Description

[0014] Figure 1 This is a perspective view of the electronic control device of the first embodiment.

[0015] Figure 2 From Figure 1 A perspective view of the electronic control device of the first embodiment, viewed from the opposite side.

[0016] Figure 3 This is a cross-sectional view showing the electronic control device of the first embodiment.

[0017] Figure 4 It is a three-dimensional diagram representing an existing electronic control device.

[0018] Figure 5 It is a cross-sectional view of an existing electronic control device.

[0019] Figure 6 It is a graph showing the relationship between the thickness of the thick-walled section and the height of the heat sink fins and the temperature rise of the electronic components.

[0020] Figure 7 This is a graph showing the temperature reduction effect when two electronic components are formed with one thick-walled section.

[0021] Figure 8 This is a cross-sectional view showing the electronic control device of the second embodiment.

[0022] Figure 9 This is a cross-sectional view showing a comparison with the electronic control device of the reference example. Detailed Implementation

[0023] The following are examples of embodiments of the electronic control device, with reference to... Figures 1-9 This will be explained. Additionally, common components will be labeled with the same reference numerals in all figures.

[0024] 1. First Embodiment Example

[0025] 1-1. Example of the structure of an electronic control device

[0026] First, regarding the structure of the electronic control device in the first embodiment (hereinafter referred to as "this example"), refer to... Figures 1 to 7 Please provide an explanation.

[0027] Figure 1 and Figure 2 It is a three-dimensional diagram representing an electronic control device. Figure 3 This is a cross-sectional view of the electronic control device.

[0028] Figures 1 to 3 The device shown is an electronic control unit installed in a motor vehicle, containing electronic circuits for controlling the vehicle. For example... Figure 1 and Figure 2 As shown, the electronic control device 1 has a first housing 2 and a second housing 3 forming a housing. The first housing 2 is formed as a hollow cover with one open side. The second housing 3 is formed as a generally flat plate. The second housing 3 is fixed to the first housing 2 by means of fixing bolts 4 in a manner that closes the opening of the first housing 2.

[0029] In addition, such as Figure 3 As shown, the electronic control device 1 includes a circuit board 6 housed inside a first housing 2 and a second housing 3, and an electronic component 8 representing a heating element. The circuit board 6 is mounted on the second housing 3. Furthermore, a space is formed between the mounting surface of the circuit board 6 and the first housing 2.

[0030] Electronic component 8 is mounted on circuit board 6 via conductive bonding member 7 made of solder or the like. Additionally, heat-conducting member 9 is sandwiched between electronic component 8 and first housing 2.

[0031] Multiple heat dissipation fins 10 are formed on the outer surface 2a of the first housing 2. The heat dissipation fins 10 protrude from the outer surface 2a of the first housing 2 in a direction away from the second housing 3. In addition, an outer thick-walled portion 11 is formed in the outer surface 2a of the first housing 2 at a position opposite to the electronic component 8. The outer thick-walled portion 11 protrudes from the outer surface 2a of the first housing 2 in a direction away from the electronic component 8, that is, on the outer side of the first housing 2.

[0032] Furthermore, heat dissipation fins 10 are also formed on the outer thick-walled portion 11. The heat dissipation fins 10 on the outer thick-walled portion 11 are set to be shorter than the heat dissipation fins 10 in other locations. That is, the length obtained by adding the height l of the heat dissipation fins 10 formed on the outer thick-walled portion 11 to the thickness of the outer thick-walled portion 11 is set to be the same length as or shorter than the height L of the other heat dissipation fins 10. As a result, it is possible to prevent the portion of the housing in the first housing 2 where the outer thick-walled portion 11 is formed from becoming larger.

[0033] If the dimensions of the casing have a margin, the length obtained by adding the height l of the heat dissipation fins 10 formed on the outer thick wall portion 11 to the thickness of the outer thick wall portion 11 can be longer than the height L of the other heat dissipation fins 10. This can further improve the heat dissipation effect.

[0034] In addition, such as Figure 3 As shown, an inner thick-walled portion 12 is formed on the inner surface of the first housing 2, opposite to the electronic component 8. The inner thick-walled portion 12 protrudes from the inner surface of the first housing 2 toward the electronic component 8, that is, toward the inner side of the first housing 2. In addition, the inner thick-walled portion 12 is formed in the first housing 2 at the location where the outer thick-walled portion 11 is provided.

[0035] In this example, the thickness of the outer thick-walled portion 11 is equal to or greater than the thickness of the inner thick-walled portion 12. Here, the section connecting the outer thick-walled portion 11 and the inner thick-walled portion 12 is a thin-walled portion. Furthermore, the thickness of the thick-walled portion, composed of the outer thick-walled portion 11, the inner thick-walled portion 12, and the thin-walled portion, is greater than the average thickness of the first housing 2. Hereinafter, the inner thick-walled portion 12, the outer thick-walled portion 11, and the thin-walled portion connecting the inner thick-walled portion 12 and the outer thick-walled portion 11 will be collectively referred to as the thick-walled portion. A heat-conducting member 9 is sandwiched between the inner thick-walled portion 12 and the electronic component 8. Heat generated in the electronic component 8 is transferred via the heat-conducting member 9 to the inner thick-walled portion 12, the outer thick-walled portion 11, and the heat sink fins 10. In this example, the electronic control device 1 uses the heat sink fins 10, the inner thick-walled portion 12, and the outer thick-walled portion 11 to cool the electronic component 8 via natural air cooling.

[0036] Furthermore, such as Figure 3 As shown, the inner thick-walled portion 12 and the outer thick-walled portion 11 are formed separately for each of the plurality of electronic components 8 mounted on the circuit board 6. That is, the inner thick-walled portion 12 and the outer thick-walled portion 11 are formed independently for each electronic component 8. Hereinafter, the inner thick-walled portion 12, the outer thick-walled portion 11, and the thin-walled portion connecting the inner thick-walled portion 12 and the outer thick-walled portion 11 will be collectively referred to as thick-walled portions. Furthermore, two adjacent thick-walled portions in the first housing 2 are connected by thin-walled portions at locations other than the inner thick-walled portion 12 and the outer thick-walled portion 11 in the first housing 2.

[0037] 1-2. Existing Examples

[0038] Next, refer to Figure 4 and Figure 5 Explain the existing electronic control device 100.

[0039] Figure 4 This is a perspective view of an existing electronic control device 100. Figure 5 This is a cross-sectional view showing the existing electronic control device 100. Furthermore, for parts common to the electronic control device 1 in this example, the same reference numerals are used and repeated descriptions are omitted.

[0040] like Figure 4 and Figure 5 As shown, the electronic control device 100 has a first housing 102 constituting the housing and a circuit board 6 housed within the housing. Electronic components 8 are mounted on the circuit board 6 via conductive bonding members 7. A plurality of heat dissipation fins 110 are formed on the outer surface 102a of the first housing 102. Furthermore, an inner thick-walled portion 112 is formed on the inner surface of the first housing 102 at a position opposite to the electronic components 8. The inner thick-walled portion 112 protrudes from the inner surface of the first housing 102 toward the electronic components 8, i.e., toward the inner side of the first housing 2.

[0041] in addition, Figure 5 The existing electronic control device 100 shown does not have a structure equivalent to the external thick-walled portion 11 in this example. Therefore, in the existing electronic control device 100, sufficient heat dissipation performance cannot be ensured by using only heat dissipation fins 110.

[0042] In contrast, according to the electronic control device 1 of this example, at the location in the first housing 2 where it is thermally coupled to the heat-generating component, i.e., the electronic component 8, not only is an internal thick-walled portion 12 locally provided, but an external thick-walled portion 11 with increased thickness is also locally provided on the outside. This increases the heat capacity of the first housing 2 using the external thick-walled portion 11, improving heat dissipation performance. Furthermore, by also providing heat dissipation fins 10 on the external thick-walled portion 11, heat dissipation performance can be further improved. As a result, even electronic components that generate increased heat, such as electronic control devices used in advanced driver assistance systems (ADAS) and autonomous driving systems (AD), can be adequately cooled.

[0043] Furthermore, by providing the external thick-walled portion 11, the necessary heat transfer to the air can be ensured, thus enabling natural air cooling of the electronic components 8. Alternatively, forced air cooling using a fan can also be employed as a cooling method.

[0044] 1-3. Thickness of the thick-walled section and height of the heat dissipation fins

[0045] Next, refer to Figure 6This explains the relationship between the thickness of the thick-walled portion of the first housing 2, namely the inner thick-walled portion 12 and the outer thick-walled portion 11, and the height l of the heat dissipation fins provided on the outer thick-walled portion 11.

[0046] Figure 6 It is a graph showing the relationship between the thickness of the thick-walled section and the height of the heat sink fins and the temperature rise of the electronic components. Figure 6 The vertical axis shown represents the temperature rise ΔTj of electronic component 8.

[0047] Here, as Figure 3 As shown, the thickness t of the thick-walled portion of the first housing 2 includes the thickness of the inner thick-walled portion 12, the outer thick-walled portion 11, and the thin-walled portion. Furthermore, Figure 6 The horizontal axis shown represents (thickness t of the thick-walled portion) / (thickness t of the thick-walled portion + height l of the heat dissipation fins arranged on the outer thick-walled portion 11).

[0048] It can be known Figure 6 The graph shown is not a linear relationship, but rather a relationship with inflection points. Furthermore, as... Figure 6 As shown, when the ratio of (thickness t of the thick wall portion) / (thickness t of the thick wall portion + height l of the heat dissipation fins arranged on the outer thick wall portion 11) is 0.4 or more and less than 1, heat dissipation performance can be optimized.

[0049] Furthermore, in the electronic control device 1 of this example, the heat generated by the heat-generating component, namely the electronic component 8, is taken into consideration, so as to... Figure 6 The volume of the thick-walled section is set in a manner that generates the inflection point peak. Then, the thickness t and height l of the thick-walled sections 11 and 12 and the heat dissipation fins 10 near the region of the inflection point peak are set. This allows for maximizing heat dissipation performance within a specified housing size. Here, when multiple electronic components (heat-generating components) 8 are arranged in a single thick-walled section, as described later... Figure 7 As shown, the thick-walled portion has insufficient heat capacity, meaning it tends not to produce an inflection point. Therefore, it is preferable to divide the thick-walled portion according to the number of electronic components 8.

[0050] 1-4. Number of electronic components and number of thick-walled sections

[0051] Next, refer to Figure 7 Explain the relationship between the number of electronic components and the number of thick-walled sections.

[0052] Figure 7 This is a graph showing the temperature reduction effect when two electronic components (8) form a thick-walled section. Figure 7 The vertical axis shown represents the temperature rise ΔTj of electronic component 8. Furthermore, Figure 7 The horizontal axis shown represents (thickness t of the thick-walled portion) / (thickness t of the thick-walled portion + height l of the heat dissipation fins arranged on the outer thick-walled portion 11).

[0053] like Figure 7 As shown, in the case where two electronic components 8 form a thick-walled section, with Figure 6 The example shown is different; no inflection point was observed, and the relationship is nearly linear. Furthermore, when (thickness t of the thick-walled portion) / (thickness t of the thick-walled portion + height l of the heat dissipation fins arranged on the outer thick-walled portion 11) is 0.5, the temperature rise ΔTj of the electronic component 8 reaches 164℃ or 163℃. In contrast, as... Figure 6 As shown, when a thick-walled portion is formed on an electronic component 8, the temperature rise ΔTj of the electronic component 8 is suppressed to 57.75°C when (thickness t of the thick-walled portion) / (thickness t of the thick-walled portion + height l of the heat dissipation fins arranged on the outer thick-walled portion 11) is 0.5.

[0054] This is because, when a thick-walled portion is formed for multiple electronic components 8, heat from the multiple electronic components 8 is concentrated in the thick-walled portion, causing thermal interference between the electronic components 8, and the heat capacity of the thick-walled portion is insufficient. Therefore, it is preferable to... Figure 3 As shown, an inner thick-walled portion 12 and an outer thick-walled portion 11 are independently formed for each electronic component 8. This prevents heat from multiple electronic components 8 from concentrating in a single inner thick-walled portion 12 and outer thick-walled portion 11, thus avoiding insufficient heat capacity and heat transfer.

[0055] That is, by providing an inner thick-walled portion 12 and an outer thick-walled portion 11 separate for each electronic component 8, heat transfer between electronic components can be suppressed from thin-walled portions in locations other than the inner thick-walled portions 12 and outer thick-walled portions 11 within the first housing 2. This reduces the thermal impact between the multiple electronic components 8. By dispersing the heat dissipation portion in this way, the heat dissipation performance of the heat sink fins 10, the inner thick-walled portion 12, and the outer thick-walled portion 11 can be improved.

[0056] 2. Second Implementation Example

[0057] Next, refer to Figure 8 The electronic control device of the second embodiment will be described.

[0058] Figure 8 This is a perspective view showing the protective component of the electronic control device in the second embodiment.

[0059] The electronic control device of the second embodiment differs from the electronic control device 1 of the first embodiment in the relationship between the thickness of the outer thick-walled portion and the inner thick-walled portion. Therefore, for the parts common to the electronic control device 1 of the first embodiment, the same reference numerals are used and repeated descriptions are omitted.

[0060] like Figure 8As shown, the first housing 2A is provided with heat dissipation fins 10, an inner thick-walled portion 12, and an outer thick-walled portion 11A. In the second embodiment, the thickness of the outer thick-walled portion 11A is set to be thinner than the thickness of the inner thick-walled portion 12. When the thickness of the outer thick-walled portion 11A is thinner than that of the inner thick-walled portion 12, the heat capacity of the first housing 2 can be increased by the outer thick-walled portion 11A, thereby improving heat dissipation performance.

[0061] In addition, according to Figure 8 The electronic control device of the second embodiment shown can increase the length of the heat dissipation fins 10 disposed on the outer thick-walled portion 11A compared to the electronic control device 1 of the first embodiment. Therefore, the electronic control device of the second embodiment is preferably used for forced air cooling by using a fan to bring air into contact with the heat dissipation fins 10. In contrast, in natural air cooling, the electronic control device 1 of the first embodiment, which thickens the outer thick-walled portion 11A to improve heat capacity and heat dissipation effect, is preferred.

[0062] The other structures are the same as those of the electronic control device 1 in the first embodiment, so their description is omitted. The electronic control device of this second embodiment can also achieve the same effects as the electronic control device 1 of the first embodiment described above.

[0063] 3. Comparison with the reference example

[0064] Next, refer to Figure 9 This section explains the comparison between the electronic control device of the reference example and the electronic control device 1 of this example.

[0065] Figure 9 This is a cross-sectional view comparing an electronic control device with a case where the thickness of the outer and inner thick-walled sections is changed while the thickness of the thick-walled section remains the same. Figure 9 (a) and Figure 9 (c) is a cross-sectional view of the electronic control device of the reference example. Figure 9 (b) is a cross-sectional view of the electronic control device 1 in this example.

[0066] Figure 9 The electronic control device shown in (a) is an electronic control device without an external thick-walled portion. Figure 9 In the conventional electronic control device shown in (a), the thickness of the internal thick-walled portion 112 is increased to ensure heat capacity, and the internal thick-walled portion 112, which serves as a heat sink, is increased inward into the first housing 102. As a result, there is a problem that the temperature around the heat-generating component, i.e., the electronic component 8, rises due to the internal thick-walled portion 112.

[0067] In addition, because the thickness of the internal thick-walled portion 112 is increased, the mounting distance of the electronic components 8 is also increased, resulting in a decrease in the mounting density of the electronic components 8 on the circuit board 6.

[0068] Figure 9 In the electronic control device shown in (c), there is no internal thick-walled portion; instead, an external thick-walled portion 11B is provided on the outside of the first housing 2B, opposite to the electronic component 8. In this case, the first housing 2B is close to the circuit board 6, so there is a relatively high risk of interference between the first housing 2B and other electronic components. Furthermore, because there is no internal thick-walled portion, the space inside the housing is reduced, and the heat of the electronic component 8 is easily trapped inside the housing. As a result, there is a problem of temperature rise inside the housing.

[0069] In addition, in order to prevent the internal space of the casing from shrinking, the thickness of the heat-conducting component 9 needs to be increased, which leads to increased costs.

[0070] In contrast, according to the electronic control device 1 of this example, by providing an internal thick-walled portion 12 in the first housing 2, it is possible to prevent the internal space of the housing from shrinking, and to prevent the electronic components 8 from being thermally trapped inside the housing. Furthermore, the thickness of the heat-conducting component 9 can be reduced, thereby achieving cost reduction. In addition, as described above, the heat capacity of the first housing 2 can be increased by using the external thick-walled portion 11 and the internal thick-walled portion 12, thereby improving heat dissipation performance.

[0071] Furthermore, the invention is not limited to the embodiments described above and shown in the accompanying drawings; various modifications can be made without departing from the inventive spirit described in the claimed technical solutions. Additionally, a portion of the structure of one embodiment can be replaced with the structure of another embodiment, or the structure of another embodiment can be added to the structure of one embodiment. Moreover, for a portion of the structure of another embodiment, other structures can be added, deleted, or replaced.

[0072] In addition, the words “parallel” and “orthogonal” are used in this specification, but they do not only mean strictly “parallel” and “orthogonal”, but can also include “parallel” and “orthogonal”, and further, “approximately parallel” and “approximately orthogonal” within the range where they can perform their functions.

[0073] Explanation of reference numerals in the attached figures

[0074] 1…electronic control device, 2, 2A…first housing, 2a…outer exterior, 3…second housing, 6…circuit board, 7…conductive bonding component, 8…electronic component (heat-generating component), 9…heat-conducting component, 10…heat dissipation fins, 11…outer thick-walled portion, 11A…outer thick-walled portion, 12…inner thick-walled portion.

Claims

1. An electronic control device, characterized in that, include: Circuit boards capable of mounting electronic components; A housing for storing the circuit board containing the electronic components; Multiple heat dissipation fins protrude outward from the outer side of the housing, i.e., the outer surface. An outer thick-walled portion, formed in the outer portion of the housing at a position opposite to the electronic component mounted on the circuit board, protrudes outward from the outer portion; An internal thick-walled portion is formed on the inner surface of the housing, i.e., the inner part, at a position opposite to the electronic component mounted on the circuit board, and protrudes from the inner part toward the electronic component; and A thin-walled portion that connects the outer thick-walled portion to the inner thick-walled portion. The thickness of the thick-walled portion, which is composed of the outer thick-walled portion, the inner thick-walled portion, and the thin-walled portion, is greater than the average thickness of the shell. The heat dissipation fins are formed on the outer thick-walled portion.

2. The electronic control device as described in claim 1, characterized in that: The length obtained by adding the height of the heat dissipation fins formed on the outer thick-walled portion to the thickness of the outer thick-walled portion is set to be the same as or shorter than the height of heat dissipation fins formed at a location different from the outer thick-walled portion.

3. The electronic control device as described in claim 1, characterized in that: Multiple electronic components are mounted on the circuit board. The inner thick-walled portion and the outer thick-walled portion are formed separately for each of the electronic components.

4. The electronic control device as described in claim 1, characterized in that: The thickness of the outer thick-walled portion is formed to be equal to or greater than the thickness of the inner thick-walled portion.

5. The electronic control device as described in claim 1, characterized in that: A heat-conducting component is provided between the internal thick-walled portion and the electronic component.

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