Substrate fixing structure

Abstract

To provide a substrate fixing structure which efficiently transfers heat from a heating component to a member to which a substrate is fixed (a fixed member) while fixing the substrate to the fixed member.SOLUTION: A substrate fixing structure 1 fixes a substrate 2, including an electronic component 20 on a first surface 2a, to a housing bottom plate 3a so that a second surface 2b faces the housing bottom plate 3a side. The substrate fixing structure 1 includes: a first spacer 11 disposed between the substrate 2 and the housing bottom plate 3a; and a metal screw 10 which sandwiches the substrate 2 and the first spacer 11 between the housing bottom plate 3a and a screw head section 10a. A rear surface of a flange portion 10c of the screw head section 10a is in contact with the electronic component 20.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a substrate fixing structure for fixing a substrate having a heat-generating component. [Background technology]

[0002] As electronic components become smaller and their performance improves, the surface area of ​​each electronic component may not be enough to dissipate heat. For this reason, heat dissipation measures (heat dissipation) are being implemented by actively transferring heat from heat-generating components (electronic components that generate heat) to other components. For example, Patent Document 1 describes attaching a heat sink to a heat-generating component to dissipate heat. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility Model Registration No. 3068039 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, heat can be transferred from a heat-generating component to a fixed member, such as a housing, to which a substrate is fixed, other than a heat sink. However, a heat-generating component may be provided on the upper surface of a substrate, and the substrate may be fixed to the fixed member with the lower surface of the substrate facing the fixed member. In this case, since the heat-generating component does not face the fixed member, heat must be transferred from the heat-generating component to the fixed member via the substrate. Furthermore, while a fixing structure is provided to fix the substrate to the fixed member, it may be difficult to provide a heat transfer structure other than this fixing structure from the perspective of space saving.

[0005] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a substrate fixing structure that can efficiently transfer heat from a heat-generating component to a fixed member while fixing the substrate to the fixed member. [Means for solving the problem]

[0006] One aspect of the present invention is a substrate fixing structure that fixes a substrate having a heat-generating component on a first surface to a member to be fixed so that a second surface opposite the first surface faces the member to be fixed, and includes a first spacer arranged between the second surface of the substrate and the member to be fixed, and a metal screw that is inserted into a substrate hole provided in the substrate and has its tip attached to the member to be fixed, and that clamps the substrate and first spacer between the member to be fixed and the screw head, and the back surface of the flange portion of the screw head abuts against the heat-generating component.

[0007] In this board fixing structure, a board can be fixed to a member to be fixed by a screw attached to the member to be fixed. The back surface of the flange of the screw head abuts against the heat-generating component, and the screw is made of metal. Therefore, in this board fixing structure, heat can be transferred from the heat-generating component mounted on the first surface of the board to the member to be fixed via the screw. In other words, by using the screw, the board fixing structure can transfer heat from the first surface of the board on which the heat-generating component is mounted to the second surface, penetrating the board. In this way, the board fixing structure can efficiently transfer heat (radiate heat) from the heat-generating component to the member to be fixed while fixing the board to the member to be fixed.

[0008] The above-mentioned substrate fixing structure may further include a thermal conductor having one surface contacting the heat-generating component and the other surface contacting the rear surface of the flange portion of the screw head, the thermal conductor having a hardness lower than that of the screw head. In this case, the thermal conductor can be in closer contact with the screw head and the heat-generating component, improving heat transfer between the screw head and the heat-generating component. This allows the substrate fixing structure to more efficiently transfer heat from the heat-generating component to the fixed member.

[0009] The above-mentioned substrate fixing structure may further include a second spacer, one end of which faces the flange of the screw head and the other end of which faces the first surface of the substrate, and the second spacer may be sandwiched between the screw head and the first surface of the substrate. In this case, the second spacer can ensure a distance between the screw head and the first surface of the substrate even when the screw is tightened. This allows the substrate fixing structure to prevent the heat-generating component from being excessively compressed by the screw head. Furthermore, by including the second spacer, the substrate fixing structure can firmly clamp the substrate between the screw head and the fixed member when the screw is tightened.

[0010] The above-mentioned board fixing structure may further include a metal presser plate having an outer shape larger than the screw head, one surface of which abuts against the heat-generating component and the other surface of which abuts against the back surface of the flange portion of the screw head. In this case, the presser plate can thermally connect the screw head and the heat-generating component even if the screw head cannot directly abut against the heat-generating component. This allows the board fixing structure to efficiently transfer heat from the heat-generating component to the fixed member even if the screw head cannot directly abut against the heat-generating component.

[0011] The above-mentioned substrate fixing structure may further include a thermal conductor having one surface abutting the heat-generating component and the other surface abutting one surface of the presser plate, and the thermal conductor may have a lower hardness than the presser plate. In this case, the thermal conductor can be in closer contact with the presser plate and the heat-generating component, improving heat transfer between the presser plate and the heat-generating component. This allows the substrate fixing structure to more efficiently transfer heat from the heat-generating component to the fixed member.

[0012] The above-mentioned substrate fixing structure may further include a second spacer, one end of which abuts against one surface of the pressure plate and the other end of which abuts against the first surface of the substrate. In this case, the second spacer can maintain a distance between the pressure plate and the first surface of the substrate even when the screw is tightened. This allows the substrate fixing structure to prevent the heat-generating component from being excessively compressed by the pressure plate. Furthermore, by including the second spacer, the substrate fixing structure can firmly clamp the substrate between the screw head and the fixed member when the screw is tightened.

[0013] In the above-described substrate fixing structure, the first spacer may be made of metal, and the first spacer may have a through hole through which the threaded portion of the screw passes, and the inner surface of the through hole may be formed with a thread that engages with the threaded portion. In this case, the substrate fixing structure may use the metal first spacer as a heat transfer path from the heat-generating component to the fixed member in addition to the screw. Furthermore, because the first spacer and the screw are engaged by the thread, the contact area between the first spacer and the screw is increased. Therefore, the substrate fixing structure may efficiently transfer heat between the first spacer and the screw, and also efficiently transfer heat to the fixed member via the first spacer and the screw. [Effects of the Invention]

[0014] According to one aspect of the present invention, heat can be efficiently transferred from the heat-generating component to the fixed member while the substrate is fixed to the fixed member. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view showing the overall configuration of an electronic device to which a substrate fixing structure according to a first embodiment is applied. [Figure 2] FIG. 2 is a top view of the substrate fixing structure and its surroundings shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line II-II in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the periphery of a substrate fixing structure according to a modified example. [Figure 5]FIG. 5 is a top view of the substrate fixing structure and its surroundings according to the second embodiment. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding elements are designated by the same reference numerals, and redundant description will be omitted.

[0017] (First embodiment) First, a first embodiment of a board fixing structure will be described. As shown in Fig. 1, electronic equipment D includes a board 2 having a plurality of electronic components (heat-generating components) 20, and a housing 3 that houses the board 2. In Fig. 1, a portion of the housing 3 is broken away to show the board 2 inside the housing 3. The board 2 is fixed to a housing bottom plate (fixed member) 3a of the housing 3 by a board fixing structure 1. In this embodiment, the housing bottom plate 3a is a metal block such as a housing or casing.

[0018] The surface of the substrate 2 that faces the bottom plate 3a of the housing is referred to as the second surface 2b, and the surface opposite the second surface 2b is referred to as the first surface 2a. In other words, the first surface 2a does not face the bottom plate 3a of the housing. In this embodiment, a plurality of electronic components 20 are provided on the first surface 2a of the substrate 2. In addition to the electronic components 20, the substrate 2 is also provided with connectors 21 and the like that connect wiring and the like to the circuitry of the substrate 2.

[0019] The board fixing structure 1 fixes a board 2 having electronic components 20 on a first surface 2a to the housing bottom plate 3a so that the second surface 2b faces the housing bottom plate 3a. The electronic components 20 generate heat when powered (operating). The board fixing structure 1 fixes the board 2 to the housing bottom plate 3a and guides (dissipates) the heat generated by the electronic components 20 to the housing bottom plate 3a. A plurality of board fixing structures 1 are provided on the board 2 according to the number of electronic components 20. Below, a detailed configuration will be explained using one board fixing structure 1 as a representative of the plurality of board fixing structures 1 provided on the board 2.

[0020] Here, as an example, a case will be described in which the substrate fixing structure 1 fixes the substrate 2 to the housing bottom plate 3a while conducting heat generated by two electronic components 20 provided on the first surface 2a to the housing bottom plate 3a. As shown in Figures 2 and 3, the substrate fixing structure 1 that fixes the substrate 2 includes a screw 10, a first spacer 11, a second spacer 12, and a TIM (Thermal Interface Material) 13.

[0021] The first spacer 11 is disposed between the second surface 2b of the substrate 2 and the housing bottom plate 3a. In this embodiment, the first spacer 11 is made of metal. The first spacer 11 has a cylindrical shape. The first spacer 11 has a through hole 11a through which the threaded portion 10b of the screw 10 is passed. The inner peripheral surface of the through hole 11a has a thread 11b that engages with the threaded portion 10b. In this embodiment, the first spacer 11 may be, for example, a hexagonal cylindrical spacer.

[0022] The second spacer 12 is disposed between the first surface 2a of the substrate 2 and the screw head 10a of the screw 10. In this embodiment, the second spacer 12 is made of metal. The second spacer 12 is cylindrical. The threaded portion 10b of the screw 10 passes through the second spacer 12. One end of the second spacer 12 faces the collar portion 10c of the screw head 10a, and the other end of the second spacer 12 faces the first surface 2a of the substrate 2. In this embodiment, one end of the second spacer 12 abuts against the back surface of the collar portion 10c of the screw head 10a (the surface of the collar portion 10c facing the substrate 2), and the other end of the second spacer 12 abuts against the first surface 2a of the substrate 2.

[0023] The screw 10 has a threaded portion 10b inserted into a board hole 2h provided in the board 2, and a tip of the threaded portion 10b attached to the housing bottom plate 3a. The screw 10 is made of metal. In this embodiment, the tip of the threaded portion 10b of the screw 10 engages with a screw hole 3h provided in the housing bottom plate 3a. The screw 10 clamps the second spacer 12, the board 2, and the first spacer 11 between the screw head 10a and the housing bottom plate 3a.

[0024] In this embodiment, the screw head 10a has a large flange portion 10c. The flange portion 10c is the portion of the screw head 10a that protrudes outward from the threaded portion 10b. The screw 10 is positioned so that the flange portion 10c can cover the electronic component 20. The electronic component 20 is located between the flange portion 10c and the board 2. In this way, the installation positions of the electronic component 20 and the screw 10 on the board 2 are set so that the screw 10 is located near the electronic component 20 that dissipates heat.

[0025] The TIM 13 is disposed between the collar portion 10c of the screw 10 and the electronic component 20. The TIM 13 is made of, for example, a thermal interface material, a thermally conductive sheet, or the like. The TIM 13 functions as a thermal conductor that further improves heat transfer between the electronic component 20 and the collar portion 10c of the screw 10. In other words, the TIM 13 functions to reduce the contact thermal resistance between the two members (to facilitate heat transfer). More specifically, one surface of the TIM 13 abuts against the electronic component 20, and the other surface abuts against the back surface of the collar portion 10c of the screw head 10a. The TIM 13 has a lower hardness than the screw head 10a (collar portion 10c). Note that hardness here refers to ease of deformation. Therefore, low hardness means ease of deformation.

[0026] That is, the TIM 13 can be in closer contact with the electronic component 20 and can be in closer contact with the flange portion 10c than when the flange portion 10c is in direct contact with the electronic component 20. The TIM 13 can further improve heat transfer between the flange portion 10c and the electronic component 20 than when the flange portion 10c is in direct contact with the electronic component 20. In this way, the back surface of the flange portion 10c of the screw head 10a of the screw 10 is in contact with the electronic component 20 via the TIM 13. Furthermore, because the TIM 13 is easily deformed, it can be in close contact with the two electronic components 20 even if the heights of the two electronic components 20 are different from each other.

[0027] Next, the heat transfer path that transfers heat from the electronic component 20 provided on the first surface 2a of the substrate 2 to the housing bottom plate 3a will be described with reference to FIG. 3. Heat generated in the electronic component 20 is transferred from the flange portion 10c of the screw head 10a to the screw head 10a via the TIM 13, as shown by arrow A1. The heat transferred to the screw head 10a is transferred from the screw head 10a to the threaded portion 10b, as shown by arrows A1 and A2. The heat transferred to the threaded portion 10b is transferred from the threaded portion 10b of the screw 10 to the housing bottom plate 3a, as shown by arrows A2 and A3. In this way, the heat generated in the electronic component 20 is transferred to the housing bottom plate 3a via the TIM 13 and the screw 10, as shown by arrows A1 to A3.

[0028] In addition, heat generated in the electronic component 20 is also transferred to the substrate 2. The heat transferred to the substrate 2 is transferred from the substrate 2 to the first spacer 11 as shown by arrows A4 and A5. The heat transferred to the first spacer 11 is transferred from the first spacer 11 to the housing bottom plate 3a as shown by arrows A5 and A3.

[0029] The second spacer 12 can also be a heat transfer path, as indicated by arrow A6. Depending on the temperature difference between the TIM 13 and the screw head 10a and the temperature of the substrate 2, the second spacer 12 may transfer heat from the screw head 10a side to the substrate 2 side, or from the substrate 2 side to the screw head 10a side.

[0030] As described above, in this board fixing structure 1, the board 2 can be fixed to the housing bottom plate 3a by the screw 10 attached to the housing bottom plate 3a. Furthermore, the back surface of the flange portion 10c of the screw head 10a of this screw 10 abuts against the electronic component 20, and the screw 10 is made of metal. Therefore, in this board fixing structure 1, heat can be transferred from the electronic component 20 provided on the first surface 2a of the board 2 to the housing bottom plate 3a via the screw 10. In other words, by using the screw 10, the board fixing structure 1 can transfer heat from the first surface 2a of the board 2 on which the electronic component 20 is provided to the second surface 2b through the board 2. In this way, the board fixing structure 1 can efficiently transfer (dissipate) heat from the electronic component 20 to the housing bottom plate 3a while fixing the board 2 to the housing bottom plate 3a.

[0031] The board fixing structure 1 includes a TIM 13, one surface of which contacts the electronic component 20 and the other surface of which contacts the back surface of the flange portion 10c of the screw head 10a. In this case, the TIM 13 can better adhere to the flange portion 10c of the screw head 10a and the electronic component 20, improving the heat transfer between the screw head 10a and the electronic component 20. This allows the board fixing structure 1 to more efficiently transfer heat from the electronic component 20 to the housing bottom plate 3a.

[0032] The board fixing structure 1 includes a second spacer 12 disposed between the flange portion 10c of the screw head 10a and the first surface 2a of the board 2. In this case, the second spacer 12 can ensure a gap between the screw head 10a and the first surface 2a of the board 2 even when the screw 10 is tightened. This allows the board fixing structure 1 to prevent the electronic component 20 from being excessively compressed by the screw head 10a. Furthermore, by including the second spacer 12, the board fixing structure 1 can firmly fix the board 2 between the screw head 10a and the housing bottom plate 3a when the screw 10 is tightened.

[0033] The first spacer 11 is made of metal. Threads 11b are formed on the inner circumferential surface of the through hole 11a of the first spacer 11. The threads 11b of the first spacer 11 are engaged with the threaded portion 10b of the screw 10. In this case, the substrate fixing structure 1 can use the metal first spacer 11 as a heat transfer path from the electronic component 20 to the housing bottom plate 3a in addition to the screw 10. Furthermore, because the first spacer 11 and the screw 10 are engaged with each other by the threads, the contact area between the first spacer 11 and the threaded portion 10b of the screw 10 is increased. Therefore, the substrate fixing structure 1 can efficiently transfer heat between the first spacer 11 and the screw 10, and also efficiently transfer heat to the housing bottom plate 3a via the first spacer 11 and the screw 10.

[0034] In the board fixing structure 1 according to the first embodiment, the screw 10 has a large flange 10c of the screw head 10a. However, this is not limiting, and instead of the screw 10, a screw 10A having a small flange 10c may be used, as shown in FIG. 4. In this case, the board fixing structure 1 may include a large-diameter washer (presser plate) 10d passed through the threaded portion 10b of the screw 10A. The washer 10d is made of metal. The washer 10d has a larger outer diameter than the screw head 10a. One surface of the washer 10d abuts against the electronic component 20, and the other surface abuts against the back surface of the flange 10c of the screw head 10a. In other words, the back surface of the flange 10c of the screw head 10a of the screw 10A abuts against the electronic component 20 via the washer 10d and the TIM 13.

[0035] In this case, the washer 10d can thermally connect the screw head 10a and the electronic component 20 even if the flange portion 10c of the screw head 10a cannot directly contact the electronic component 20. This allows the board fixing structure 1 to efficiently transfer heat from the electronic component 20 to the housing bottom plate 3a via the washer 10d.

[0036] In the first embodiment, the tip of the threaded portion 10b of the screw 10 is engaged with the threaded hole 3h provided in the bottom plate 3a of the housing. However, this is not limiting, and for example, as shown in Fig. 4, the tip of the threaded portion 10b of the screw 10A may be passed through a through-hole 3i provided in the bottom plate 3a of the housing. The screw 10A may have a nut 14 attached to the tip of the threaded portion 10b, so that the washer 10d, the second spacer 12, the substrate 2, the first spacer 11, and the bottom plate 3a of the housing are sandwiched between the screw head 10a and the nut 14.

[0037] (Second embodiment) Next, a second embodiment of the substrate fixing structure will be described. As shown in Figures 5 and 6, the substrate fixing structure 1A according to this embodiment fixes the substrate 2 to the housing bottom plate 3a of the housing 3, similar to the substrate fixing structure 1 according to the first embodiment. Hereinafter, in the substrate fixing structure 1A, components similar to those described above will be assigned the same reference numerals in the drawings, and detailed description thereof will be omitted.

[0038] In this board fixing structure 1A, even if the positions of the screws 10B and 10C (positions of the board holes 2j and 2k) and the position of the electronic component 20 are separated, heat generated in the electronic component 20 can be transferred to the housing bottom plate 3a via the screws 10B and 10C. Below, as an example, a case will be described in which the board fixing structure 1A fixes the board 2 to the housing bottom plate 3a while conducting heat generated in two electronic components 20 provided on the first surface 2a to the housing bottom plate 3a.

[0039] The substrate fixing structure 1A includes screws 10B, 10C, first spacers 11B, 11C, second spacers 12B, 12C, a TIM 13, and a presser plate 15.

[0040] The first spacers 11B and 11C are each disposed between the second surface 2b of the substrate 2 and the bottom plate 3a of the housing. In this embodiment, the first spacers 11B and 11C are made of metal. The first spacers 11B and 11C are cylindrical. The first spacer 11B has a through hole 11Ba through which the threaded portion 10b of the screw 10B is inserted. The inner circumferential surface of the through hole 11Ba has a thread 11Bb that engages with the threaded portion 10b of the screw 10B. The first spacer 11C has a through hole 11Ca through which the threaded portion 10b of the screw 10C is inserted. The inner circumferential surface of the through hole 11Ca has a thread 11Cb that engages with the threaded portion 10b of the screw 10C. In this embodiment, the first spacers 11B and 11C may be, for example, hexagonal cylindrical spacers.

[0041] One surface of the retainer plate 15 abuts against the top surfaces of the two electronic components 20, and the other surface abuts against the back surface of the flange portion 10c of the screw head 10a of the screw 10B and the back surface of the flange portion 10c of the screw head 10a of the screw 10C. The retainer plate 15 has an outer shape larger than the screw head 10a of the screw 10B and the screw head 10a of the screw 10C. The retainer plate 15 is made of metal.

[0042] More specifically, through holes 15b and 15c are provided in presser plate 15. Threaded portion 10b of screw 10B is passed through through hole 15b of presser plate 15. Threaded portion 10b of screw 10C is passed through through hole 15c of presser plate 15.

[0043] The TIM 13 is disposed between the presser plate 15 and the electronic component 20. The TIM 13 functions as a thermal conductor that further improves heat transfer between the electronic component 20 and the presser plate 15. More specifically, one surface of the TIM 13 abuts against the electronic component 20, and the other surface abuts against the presser plate 15. In other words, one surface of the presser plate 15 abuts against the electronic component 20 via the TIM 13. The TIM 13 has a lower hardness than the presser plate 15.

[0044] The second spacers 12B and 12C are each disposed between the first surface 2a of the substrate 2 and the presser plate 15. In this embodiment, the second spacers 12B and 12C are each made of metal. Furthermore, the second spacers 12B and 12C each have a cylindrical shape.

[0045] The threaded portion 10b of the screw 10B is passed through the second spacer 12B. One end of the second spacer 12B abuts against one surface of the presser plate 15, and the other end of the second spacer 12B abuts against the first surface 2a of the substrate 2. The threaded portion 10b of the screw 10C is passed through the second spacer 12C. One end of the second spacer 12C abuts against one surface of the presser plate 15, and the other end of the second spacer 12C abuts against the first surface 2a of the substrate 2.

[0046] The screw 10B has its threaded portion 10b inserted into a board hole 2j provided in the board 2, and the tip of the threaded portion 10b is attached to the housing bottom plate 3a. Similarly, the screw 10C has its threaded portion 10b inserted into a board hole 2k provided in the board 2, and the tip of the threaded portion 10b is attached to the housing bottom plate 3a. The screws 10B and 10C are made of metal. In this embodiment, the tip of the threaded portion 10b of the screw 10B engages with a threaded hole 3j provided in the housing bottom plate 3a. Similarly, the tip of the threaded portion 10b of the screw 10C engages with a threaded hole 3k provided in the housing bottom plate 3a. The screws 10B and 10C clamp the presser plate 15, second spacers 12B and 12C, the board 2, and first spacers 11B and 11C between their screw heads 10a and the housing bottom plate 3a.

[0047] In this way, the positions of the screws 10B and 10C are separated from the position of the electronic component 20. Even in this case, the board fixing structure 1A, like the board fixing structure 1 according to the first embodiment, can transfer heat generated in the electronic component 20 to the presser plate 15, and further to the housing bottom plate 3a via the screws 10B and 10C.

[0048] As described above, in this substrate fixing structure 1A, similar to the substrate fixing structure 1 of the first embodiment, the substrate 2 can be fixed to the housing bottom plate 3a while efficiently transferring (dissipating) heat from the electronic component 20 to the housing bottom plate 3a.

[0049] The board fixing structure 1A also includes a retainer plate 15 that is provided to straddle the screw 10B and the screw 10C. In this case, the retainer plate 15 can thermally connect the screw head 10a and the electronic component 20 even if the flange portion 10c of the screw head 10a cannot directly contact the electronic component 20. This allows the board fixing structure 1A to efficiently transfer heat from the electronic component 20 to the housing bottom plate 3a via the retainer plate 15.

[0050] The substrate fixing structure 1A includes a TIM 13, one surface of which contacts the electronic component 20 and the other surface of which contacts the presser plate 15. In this case, the TIM 13 can provide closer contact between the presser plate 15 and the electronic component 20, improving the heat transfer between the presser plate 15 and the electronic component 20. This allows the substrate fixing structure 1A to more efficiently transfer heat from the electronic component 20 to the housing bottom plate 3a.

[0051] The board fixing structure 1A includes second spacers 12B and 12C disposed between the presser plate 15 and the first surface 2a of the board 2. In this case, the second spacers 12B and 12C can ensure a gap between the screw heads 10a and the first surface 2a of the board 2 even when the screws 10B and 10C are tightened. This allows the board fixing structure 1A to prevent the electronic component 20 from being excessively compressed by the screw heads 10a. Furthermore, by including the second spacers 12B and 12C, the board fixing structure 1A can firmly fix the board 2 between the screw heads 10a and the housing bottom plate 3a when the screws 10 are tightened.

[0052] The first spacers 11B and 11C are each made of metal. A thread 11Bb is formed on the inner circumferential surface of the through hole 11Ba of the first spacer 11B. The thread 11Bb of the first spacer 11B engages with the threaded portion 10b of the screw 10B. Similarly, a thread 11Cb is formed on the inner circumferential surface of the through hole 11Ca of the first spacer 11C. The thread 11Cb of the first spacer 11C engages with the threaded portion 10b of the screw 10C. In this case, the substrate fixing structure 1A can use the metal first spacers 11B and 11C, in addition to the screws 10B and 10C, as a heat transfer path from the electronic component 20 to the housing bottom plate 3a. Furthermore, because the first spacers 11B and 11C engage with the screws 10B and 10C via the threads, the contact area between the first spacer 11B and the screw 10B and the contact area between the first spacer 11C and the screw 10C are increased. Therefore, the substrate fixing structure 1A can efficiently transfer heat between the first spacers 11B and 11C and the screws 10B and 10C, respectively, while also efficiently transferring heat to the housing bottom plate 3a via the first spacers 11B and 11C and the screws 10B and 10C.

[0053] The second spacers 12, 12B, and 12c may be springs, for example. When the second spacers 12 etc. are springs, they can secure the distance between the screw heads 10a and the substrate 2 as described above, while also functioning as a locking mechanism for the screws 10 etc.

[0054] The gist of the present invention will be described below. [Invention 1] A substrate fixing structure in which a substrate having a heat-generating component on a first surface is fixed to a fixed member such that a second surface opposite to the first surface faces the fixed member, a first spacer disposed between the second surface of the substrate and the fixed member; a metal screw that is inserted into a board hole provided in the board, has a tip end attached to the fixed member, and holds the board and the first spacer between the fixed member and the screw head; Equipped with A substrate fixing structure, wherein the back surface of the flange portion of the screw head abuts against the heat-generating component. [Invention 2] a heat conductor having one surface in contact with the heat generating component and another surface in contact with the back surface of the flange portion of the screw head; 2. The substrate fixing structure according to claim 1, wherein the thermal conductor has a hardness lower than that of the head of the screw. [Invention 3] The substrate fixing structure according to invention 1 or 2, further comprising a second spacer, one end of which abuts against the back surface of the flange portion of the screw head and the other end of which abuts against the first surface of the substrate. [Invention 4] The substrate fixing structure described in Invention 1 further comprises a metal pressure plate having an outer shape larger than the screw head, one surface of which abuts against the heat-generating component and the other surface of which abuts against the back surface of the flange portion of the screw head. [Invention 5] a heat conductor having one surface in contact with the heat generating component and the other surface in contact with the one surface of the presser plate; 5. The substrate fixing structure according to claim 4, wherein the thermal conductor has a hardness lower than that of the pressing plate. [Invention 6] The substrate fixing structure according to invention 4 or 5, further comprising a second spacer having one end abutting against the one surface of the pressing plate and the other end abutting against the first surface of the substrate. [Invention 7] the first spacer is made of metal, the first spacer is provided with a through hole through which the threaded portion of the screw passes, 7. The substrate fixing structure according to any one of the first to sixth aspects of the present invention, wherein a thread that engages with the screw portion is formed on the inner peripheral surface of the through hole. [Explanation of symbols]

[0055] 1,1A PCB fixing structure 2 boards 2a 1st page 2b 2nd side 2h,2j,2k board hole 3a Housing bottom plate (fixed member) 10, 10B, 10C screws 10a screw head 10b Threaded portion 10c Brim 10d Washer (holding plate) 11, 11B, 11C First spacer 11a,11Ba,11Ca through hole 11b, 11Bb, 11Cb threads 12, 12B, 12C Second spacer 13 TIM (thermal conductor) 15 Retaining plate 20 Electronic components (heat-generating components)

Claims

1. A substrate fixing structure in which a substrate having a heat-generating component on a first surface is fixed to a fixed member such that a second surface opposite to the first surface faces the fixed member, a first spacer disposed between the second surface of the substrate and the fixed member; a metal screw that is inserted into a board hole provided in the board, has a tip portion attached to the fixed member, and holds the board and the first spacer between the fixed member and the screw head; Equipped with A substrate fixing structure, wherein the back surface of the flange portion of the screw head abuts against the heat-generating component.

2. a heat conductor having one surface in contact with the heat generating component and another surface in contact with the back surface of the flange portion of the screw head; The substrate fixing structure according to claim 1 , wherein the thermal conductor has a hardness lower than that of the head of the screw.

3. a second spacer, one end of which faces the flange portion of the screw head and the other end of which faces the first surface of the substrate; The substrate fixing structure according to claim 1 , wherein the second spacer is sandwiched between the head of the screw and the first surface of the substrate.

4. 2. The substrate fixing structure according to claim 1, further comprising a metal pressure plate having an outer shape larger than that of the screw head, one surface of which abuts against the heat-generating component and the other surface of which abuts against the back surface of the flange portion of the screw head.

5. a heat conductor having one surface in contact with the heat generating component and the other surface in contact with the one surface of the presser plate; The substrate fixing structure according to claim 4 , wherein the thermal conductor has a hardness lower than that of the pressing plate.

6. The substrate fixing structure according to claim 4 or 5, further comprising a second spacer having one end abutting against the one surface of the presser plate and the other end abutting against the first surface of the substrate.

7. the first spacer is made of metal, the first spacer is provided with a through hole through which the threaded portion of the screw passes, The substrate fixing structure according to claim 1 , wherein a thread that engages with the screw portion is formed on an inner peripheral surface of the through hole.

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