Heat dissipation structure and electronic device

Abstract

The present invention provides a heat dissipation structure and electronic device having a structure that can efficiently dissipate the heat generated by an electronic circuit board from the case to the outside. [Solution] The heat dissipation structure of the present disclosure is a heat dissipation structure for an electronic device that houses a substrate on which an electronic circuit is mounted, and comprises a case in which rails for guiding the insertion of the substrate are arranged inside, and a cover provided with ribs for clamping and positioning the substrate, wherein the rails have steps configured to push up the substrate after it has been inserted into the case, and the case is configured to come into contact with the heat dissipation components provided on the substrate when the substrate is pushed up.

Description

【Technical Field】 【0001】 The present disclosure relates to a heat dissipation structure and an electronic device, and particularly to a heat dissipation structure for in-vehicle electronic devices such as an ECU (Electronic Control Unit) or a TCU (Telematics Control Unit), and an electronic device having such a heat dissipation structure. 【Background Art】 【0002】 An ECU (Electronic Control Unit) or a TCU (Telematics Control Unit), which are in-vehicle electronic devices, is a general term for devices including an electronic circuit board that controls the functions of a vehicle. In many cases, the structure of an in-vehicle electronic device houses the electronic circuit board in a case for waterproofing measures. Also, in order to suppress heat generation of the electronic circuit board, it is preferable that the heat dissipation from the case to the outside is high. 【0003】 Patent Document 1 discloses a cooling structure in which a heat sink is provided on an electronic circuit board and cooling air is passed through the case to dissipate heat from the electronic circuit board. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2002-198671 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 The cooling structure disclosed in Patent Document 1 has a problem of becoming large in size because a mechanism for flowing cooling air is provided. Also, a component that requires height, such as a heat sink, may interfere with the case when inserting the electronic circuit board into the case, and there is a risk that components provided on the electronic circuit board may be damaged. Therefore, when considering miniaturization of an in-vehicle electronic device, it is necessary to reduce the height of the heat sink, which makes it difficult to increase the heat dissipation efficiency. 【0006】 This disclosure has been made in view of the above, and aims to provide a heat dissipation structure and electronic device having a structure that can efficiently dissipate the heat generated by an electronic circuit board from the case to the outside. [Means for solving the problem] 【0007】 The heat dissipation structure of the present disclosure is a heat dissipation structure for an electronic device that houses a substrate on which an electronic circuit is mounted, comprising: a case in which rails for guiding the insertion of the substrate are arranged inside; and a cover provided with ribs for clamping and positioning the substrate, wherein the rails have steps configured to push up the substrate after it has been inserted into the case, and the case is configured to come into contact with heat dissipation components provided on the substrate when the substrate is pushed up. [Effects of the Invention] 【0008】 This disclosure provides a heat dissipation structure and an electronic device having a structure that can efficiently dissipate the heat generated by an electronic circuit board from the case to the outside. [Brief explanation of the drawing] 【0009】 [Figure 1] This is a diagram of the heat dissipation structure and electronic device relating to this disclosure. [Figure 2] This is a cross-sectional view of the case related to this disclosure. [Figure 3] This is a cross-sectional view of the substrate relating to this disclosure. [Figure 4] This is a cross-sectional view of the cover relating to this disclosure. [Figure 5] This figure illustrates the process of housing a substrate in the heat dissipation structure according to this disclosure. [Figure 6] This figure illustrates the process of housing a substrate in the heat dissipation structure according to this disclosure. [Figure 7] This figure illustrates the process of housing a substrate in the heat dissipation structure according to this disclosure. [Figure 8]This figure shows the shape of the rails provided in the case related to this disclosure. [Modes for carrying out the invention] 【0010】 The configuration example of the heat dissipation structure 100 of this disclosure will be described below with reference to the figures. The heat dissipation structure 100 shown in Figure 1 comprises a case 110 for housing a substrate 120 on which an electronic circuit is mounted, and a cover 130. Details of each component will be described later, but the heat dissipation structure 100 according to this disclosure has a structure in which the substrate 120 is slid into the case 110 and the cover 130 is fitted onto the case 110 to fix the substrate 120 to the case 110. 【0011】 Furthermore, a device in which a substrate 120 with an electronic circuit mounted on it is housed within the heat dissipation structure 100 of this disclosure is used as an in-vehicle ECU or TCU. 【0012】 Case 110 will be explained using Figure 1 and Figures 2(a) and 2(b), which are cross-sectional views of Case 110. For Case 110, the side into which the substrate 120 is inserted is referred to as the front, the side opposite the front is referred to as the back, and the left and right sides are referred to as the sides. Figure 2(a) is a cross-sectional view of Case 110 as seen from the side, and Figure 2(b) is a cross-sectional view of Case 110 along the dashed line II-II in Figure 2(a). 【0013】 Inside the case 110, rails 111 and 112 are provided to support the insertion of the substrate 120. Preferably, rail 112 is positioned in contact with the lower part of the case 110. Rail 111 is positioned above rail 112. As a result, a groove 114 is formed between rail 111 and rail 112. 【0014】 Furthermore, as shown in Figure 2(b), rails 111 and 112 are each provided in pairs facing each other inside the case 110. This forms a pair of grooves 114, and the substrate 120 is inserted into the case 110 through the pair of grooves 114, using the rails 111 and 112 as guides. 【0015】 As shown in the region surrounded by the dotted line in Fig. 2(a), the rail 112 has a configuration in which a step 113 is provided on the back side of the case 110. That is, after the substrate 120 is inserted to the depth of the case 110, it is pushed upward by the step 113. 【0016】 The material of the case 110 is preferably a resin material having a lower Young's modulus than the substrate 120 such as polybutylene terephthalate resin or polypropylene resin. Thereby, the influence of the stress applied to the substrate 120 can be reduced. Also, the material of the case 110 preferably has high heat dissipation. Thereby, the heat generated in the substrate 120 can be efficiently dissipated. 【0017】 Next, the substrate 120 on which an electronic circuit is mounted and the components attached to the substrate 120 will be described using Fig. 1 and Fig. 3 which is a cross-sectional view of the substrate120. A connector 121 is provided on any one side of the substrate 120. The substrate 120 is inserted into the case110 such that the connector 121 is disposed on the front side of the case 110. 【0018】 Mounting components 122, a heat conduction part 123, and heat dissipation components 124 are provided on the substrate120. The heat dissipation component 124 and the substrate 120 are fixed to each other by screws 125 with the mounting components 122 and the heat conduction part 123 interposed therebetween. 【0019】 The mounting component 122 is an area where heat-generating members such as electronic circuits and elements are soldered to the substrate 120. 【0020】 The heat conduction part 123 is formed of a thermal conductive material (Thermal Interface Material: TIM) for dissipating the heat generated in the mounting component 122. As the material of the heat conduction part 123, a material in which a resin such as silicone resin or epoxy resin is filled with a highly thermally conductive filler such as a metal or a carbon material is used. 【0021】 The heat dissipation component 124 serves as a heat sink. The shape of the heat dissipation component 124 is preferably C-shaped (a U-shape rotated to have an upper side). The material of the heat dissipation component 124 is preferably a resin material with a lower Young's modulus than the substrate 120, such as polybutylene terephthalate resin or polypropylene resin. This allows the heat dissipation component 124 to deform in accordance with the shape of the substrate 120 and case 110, even when it expands due to the heat generated from the mounted component 122, thereby reducing the impact of stress on the mounted component 122. 【0022】 For example, if a material with a higher Young's modulus than the substrate 120, such as aluminum, is used for the heat dissipation component 124, stress due to thermal expansion may cause stress on the solder of the mounted component 122. Therefore, it is preferable to adjust the thickness of the heat dissipation component 124 to an appropriate thickness that takes stress into consideration, such as by reducing its thickness. 【0023】 Next, the cover 130 will be described using Figure 1 and Figure 4, which is a cross-sectional view of the cover 130. The cover 130 includes a pair of upper and lower ribs 131 that sandwich and position the substrate 120, and an opening 132 through which the connector 121 provided on the substrate 120 passes. 【0024】 The substrate 120 is fixed by the step 113 of the rail 112 provided on the case 110 and by a pair of upper and lower ribs 131 provided on the cover 130. Furthermore, it is preferable that the material of the cover 130 be a resin material with a lower Young's modulus than that of the substrate 120, similar to the material of the case 110. This reduces the effect of stress on the substrate 120 even when the substrate 120 is fixed by the pair of upper and lower ribs 131. 【0025】 When the circuit board 120 is pushed all the way to the back of the case 110, the rail 112 is in contact with the circuit board 120 only at the step 113. The circuit board 120 is fixed by the step 113 of the rail 112 provided on the case 110 and a pair of upper and lower ribs 131 provided on the cover 130, but it may also be in contact with the lower surface of the rail 111 located above it. The circuit board 120 is supported more stably by being in contact with the ribs 131, the step 113, and the lower surface of the rail 111. 【0026】 The process of housing a substrate 120 on which an electronic circuit is mounted in the heat dissipation structure 100 according to this disclosure will be explained with reference to Figures 5 to 7. Figure 5 shows a cross-section of the substrate 120 and the case 110 at the time the substrate 120 is inserted into the case 110. The substrate 120 is inserted towards the rear side of the case 110 along a rail 112 located below it in a groove 114 inside the case 110. 【0027】 When one side of the circuit board 120 opposite to the side on which the connector 121 is located comes into contact with the step 113 of the rail 112 located below, the circuit board 120 is pushed up along the shape of the step 113 (see Figure 6). Then, when the circuit board 120 is pushed to the back side of the case 110 and the cover 130 is fitted onto the case 110, the circuit board 120 is positioned by the pair of upper and lower ribs 131 of the cover 130 (see Figure 7). 【0028】 As shown in Figure 7, the step 113 and rib 131 push up the substrate 120, causing the upper surface of the heat dissipation component 124 to come into contact with the back surface of the upper surface of the case 110. As a result, the heat generated in the mounted components 122 is transferred to the upper surface of the case 110 via the heat dissipation component 124, which acts as a heat sink. The heat is diffused throughout the case 110, allowing for efficient heat dissipation to the outside of the case 110. 【0029】 In the heat dissipation structure 100 according to this disclosure, heat is conducted by the heat dissipation component 124 contacting the back surface of the upper surface of the case 110. Therefore, it is preferable that the heat dissipation component 124 has a shape that increases the contact area between the heat dissipation component 124 and the case 110. Accordingly, the shape of the heat dissipation component 124 is not limited to a shape that increases the surface area, such as a fin shape or a pin shape. 【0030】 Figures 8(a) to 8(c) show examples of the shape of the step 113. In order to insert the substrate 120 to the back side of the case 110 with minimal load on the substrate 120, it is preferable that the step 113 has a shape in which the height gradually changes in the direction toward the back side of the case 110, that is, in the direction in which the substrate 120 is inserted, rather than a sudden change in height. For example, the shape of the step 113 shown in Figure 8(b) has a gentler slope compared to the shape of the step 113 shown in Figure 8(a). Alternatively, as shown in Figure 8(c), the shape may have a curvature that changes continuously. By changing the shape of the step 113 as shown in Figures 8(a) to 8(c), the substrate 120 can be inserted smoothly to the back side of the case 110 with minimal load on the substrate 120. 【0031】 Although the present disclosure has been described above with reference to embodiments, the present disclosure is not limited to the embodiments described above. Various modifications to the structure and details of the present disclosure can be made as can be understood by those skilled in the art within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate. 【0032】 Each drawing is merely illustrative to illustrate one or more embodiments. Each drawing may be associated with one or more other embodiments rather than with only one specific embodiment. As those skilled in the art will understand, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings, for example, to create embodiments not explicitly shown or described. Not all features or steps shown in any one drawing to illustrate an exemplary embodiment are necessarily required, and some features or steps may be omitted. The order of steps shown in any of the drawings may be changed as appropriate. 【0033】 Some or all of the above embodiments may also be described as follows, but are not limited to the following: (Note 1) A heat dissipation structure for an electronic device that houses a circuit board containing electronic circuits, A case having rails arranged inside to guide the insertion of the aforementioned circuit board, The system comprises a cover provided with ribs that clamp and position the substrate, The rail has a step that is configured to push up the substrate after the substrate has been inserted into the case. The case is configured such that the substrate is pushed up and comes into contact with the heat dissipation components provided on the substrate. Heat dissipation structure. (Note 2) The step in the rail has a shape in which the height gradually increases in the direction in which the substrate is inserted. The heat dissipation structure described in Appendix 1. (Note 3) The rail that guides the insertion of the substrate comprises a first rail having a step and a second rail located above the first rail. The first rail contacts the substrate only at the step. Heat dissipation structure as described in Appendix 2. (Note 4) The substrate is supported by the ribs of the cover, the step of the first rail, and the lower surface of the second rail. Heat dissipation structure as described in Appendix 3. (Note 5) The material of the case and the cover has a lower Young's modulus than the material of the substrate. A heat dissipation structure as described in any one of the appendices 1 to 4. (Note 6) An electronic device that houses a circuit board into which an electronic circuit is mounted, Equipped with a heat dissipation structure as described in any one of the appendices 1 to 5, electronic equipment. [Explanation of Symbols] 【0034】 100 Heat dissipation structure 110 cases Rails 111 and 112 113 steps 114 Groove 120 circuit boards 121 Connector 122 Mounted Components 123 Heat conduction section 124 Heat dissipation components 125 screw 130 Cover 131 Rib 132 Opening

Claims

[Claim 1] A heat dissipation structure for an electronic device that houses a circuit board containing electronic circuits, A case having rails arranged inside to guide the insertion of the aforementioned circuit board, The system comprises a cover provided with ribs that clamp and position the substrate, The rail has a step that is configured to push up the substrate after the substrate has been inserted into the case. The case is configured such that the substrate is pushed up and comes into contact with the heat dissipation components provided on the substrate. Heat dissipation structure. [Claim 2] The step in the rail has a shape in which the height gradually increases in the direction in which the substrate is inserted. The heat dissipation structure according to claim 1. [Claim 3] The rail that guides the insertion of the substrate comprises a first rail having the step and a second rail located above the first rail. The first rail contacts the substrate only at the step. The heat dissipation structure according to claim 2. [Claim 4] The substrate is supported by the ribs of the cover, the step of the first rail, and the lower surface of the second rail. The heat dissipation structure according to claim 3. [Claim 5] The material of the case and the cover has a lower Young's modulus than the material of the substrate. The heat dissipation structure according to claim 1. [Claim 6] An electronic device that houses a circuit board into which an electronic circuit is mounted, A heat dissipation structure according to any one of claims 1 to 5, electronic equipment.

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