Heat dissipation structure for wiring board, power supply device, and method for manufacturing power supply device

Abstract

To properly adjust the height of a space formed between a wiring board and a heat dissipation member even when a ready-made support member is used, and to easily assemble a heat dissipation structure to the wiring board.SOLUTION: A heat dissipation structure of a wiring board 10, which includes a switching element 12 mounted on a first board surface 1010 and a copper plate 14 mounted on a second board surface 1012, includes a heat sink 20 arranged on the first board surface 1010 side, a spacer 24 arranged between the heat sink 20 and the wiring board 10 and having a hollow portion, a heat sink sheet 22 arranged so as to contact the heat sink 20, the switching element, and a lead terminal 1410 of a copper plate 14, and a screw 26 inserted into the hollow portion of the spacer 24 and fastening the heat sink 20 to the wiring board 10, and the heat sink 20 has a recess on its surface, and the recess has a bottom with an area larger than that of the end face of the spacer 24, and the spacer 24 is arranged with one of its end faces abutting against the bottom of the recess.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a heat dissipation structure for a wiring board that dissipates heat generated by heat-generating components mounted on the wiring board, a power supply device including a wiring board on which the heat dissipation structure is assembled, and a method for manufacturing the same. [Background technology]

[0002] Conventionally, in various devices such as power supplies, a heat dissipation structure is built into the wiring board to dissipate heat from heat-generating components in order to prevent or suppress the deterioration of component characteristics or failure of electrical and electronic components such as IC chips (integrated circuits) and switching elements such as FETs mounted on the wiring board from exceeding their rated temperature.

[0003] Examples of wiring boards equipped with heat dissipation structures are shown in Figures 5(A) to 5(C). To facilitate comparison with the present invention, the wiring boards in Figures 5(A) to 5(C) are the same as those in the embodiments for explaining the present invention, and Figures 5(A) to 5(C) show cross sections of a portion corresponding to the cross section shown in Figure 3(B) used to explain the embodiments of the present invention.

[0004] The wiring board 100 shown in Figures 5(A) to (C) has a switching element 120 (heat-generating component) such as an FET mounted on a first substrate surface 101 (the bottom surface of the wiring board 100) and a copper plate 140 (heat-dissipating component) mounted on a second substrate surface 102 (the top surface of the wiring board 100). The switching element 120 mounted on the first substrate surface 101 is a surface-mounted component, and the copper plate 140 mounted on the second substrate surface 102 functions as wiring that substitutes for the board wiring of the wiring board 100. The copper plate 140 is a discrete component that is mounted with lead terminals 141 inserted through through holes in the wiring board 100 and exposed on the first substrate surface 101 side.

[0005] 5(A) to 5(C) includes a heat sink 200 (heat sink member), a heat sink sheet 220 (thermal conduction member), a spacer 240 (support member), and a screw 260 (fixing member). The heat sink sheet 220 is disposed between the wiring board 100 and the heat sink 200 so as to be in contact with the switching elements 120, the lead terminals 141 of the copper plate 140, and the surface of the heat sink 200, and conducts heat generated by the switching elements 120 to the heat sink 200 and the copper plate 140. The spacer 240 is a cylindrical member having a hollow portion and supports the heat sink 200 relative to the wiring board 100 so as to form a space between the wiring board 100 and the heat sink 200.

[0006] 5(A), a portion of one end (lower end) of spacer 240 is press-fitted into a through-hole formed in heat sink 200, the other end (upper end) of spacer 240 is abutted against first substrate surface 101 of wiring board 100, screws 260 are inserted through the through-hole of wiring board 100 and the hollow portion of spacer 240 from the second substrate surface 102 side, and spacer 240 is fastened and fixed to wiring board 100 by screws 260, thereby assembling the heat dissipation structure to wiring board 100 with a space formed between wiring board 100 and heat sink 200. Note that the hollow portion of spacer 240 in FIG. 5(A) is a screw hole.

[0007] In addition, in Figure 5(B), one end (upper end) of spacer 240 is abutted against first substrate surface 101 of wiring board 100, and the other end (lower end) of spacer 240 is abutted against the surface of heat sink 200, and screws 260 are inserted from the second substrate surface 102 side through the through hole of wiring board 100 and the hollow portion of spacer 240, and screwed into the screw hole formed in heat sink 200, thereby fastening and fixing wiring board 100 and heat sink 200 with spacer 240 between them, thereby assembling the heat dissipation structure to wiring board 100 with a space formed between wiring board 100 and heat sink 200.

[0008] In addition, in Figure 5 (C), terminals 280 extending toward the wiring board 100 are crimped onto the surface of the heat sink 200, and terminals 280 are inserted into the hollow portion of the spacer 240 and the through-holes of the wiring board 100, and one end of terminal 280 exposed on the second substrate surface 102 side of the wiring board 100 is fixed to the second substrate surface 102 of the wiring board 100 with solder 290, thereby assembling the heat dissipation structure to the wiring board 100 with a space formed between the wiring board 100 and the heat sink 200.

[0009] 5(A) to 5(C), the height (vertical length) of the space formed between the wiring board 100 and the heat sink 200 is adjusted by the height of the spacer 240, and the height is adjusted so that the compression rate of the heat sink sheet 220 in the height direction is sufficient to ensure thermal conductivity from the switching element 120 to the heat sink 200 and the copper plate 140, and is not so high that it distorts the wiring board 100 and damages the components mounted on the wiring board 100. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2017-099035 [Patent Document 2] International Publication No. 2018 / 173103 Summary of the Invention [Problem to be solved by the invention]

[0011] However, standardized spacers often have heights in increments of 0.5 mm or 1.0 mm, and when standardized spacers are used in a heat dissipation structure, it is not possible to finely adjust the height of the space formed between wiring board 100 and heat sink 200. Also, custom-made spacers may be used to adjust the height of the space formed between wiring board 100 and heat sink 200 to an appropriate height, but custom-made products are difficult to obtain and the use of custom-made products leads to increased costs.

[0012] Furthermore, in the heat dissipation structure of Figure 5(A), the spacer 240 is press-fit into the through-hole formed in the heat dissipation plate 200. Therefore, if the press-fit state of the spacer 240 changes due to vibration or the like, the height of the space formed between the wiring board 100 and the heat dissipation plate 200 will change, which will affect the compression rate of the heat dissipation sheet 220 in the height direction.

[0013] Furthermore, in the heat dissipation structure of Figure 5(B), the position of spacer 240 is not fixed and can move freely until screw 260 is inserted, so when assembling the heat dissipation structure to wiring board 100, the position of spacer 240 is not fixed, making the assembly work time-consuming and labor-intensive.

[0014] Furthermore, in the heat dissipation structure of FIG. 5(C), since terminal 280 is fixed to wiring board 100 using solder 290, soldering must be performed twice, once when mounting the component on wiring board 100, which requires more time and effort and also applies extra heat to the mounted component, which may lead to deterioration of the component characteristics or failure.

[0015] The present invention aims to provide a heat dissipation structure that allows the height of the space formed between a wiring board and a heat dissipation member to be appropriately adjusted even when a ready-made support member is used, and that allows the heat dissipation structure to be easily assembled to a wiring board, as well as a power supply unit equipped with a wiring board to which the heat dissipation structure is assembled, and a method for manufacturing the same. [Means for solving the problem]

[0016] (Heat dissipation structure of wiring board) The present invention provides a heat dissipation structure for a wiring board having at least one heat-generating component mounted on a first board surface, comprising: a heat dissipation member disposed on the first substrate surface side of the wiring board; a support member that is a cylindrical member having a hollow portion that penetrates from one end surface to the other end surface and is disposed between the heat dissipation member and the wiring board so as to form a predetermined space between the heat dissipation member and the wiring board; a heat conduction member disposed in a space between the heat dissipation member and the wiring board so as to be in contact with both the heat dissipation member and the heat generating component; a fixing member that is inserted into a hollow portion of the support member and fixes the heat dissipation member and the wiring board; Equipped with The heat dissipation member has a recess on a surface facing the wiring board, the recess is recessed on the opposite side of the wiring board and has a bottom having an area larger than that of the end face of the support member; The support member is characterized in that one of its end faces is placed in contact with the bottom of the recess.

[0017] (Discrete components mounted on the second board surface) The target wiring board is a wiring board in which discrete components are mounted on a second substrate surface opposite to a first substrate surface, The thermal conductive member is positioned so as to contact not only the heat dissipation member and the heat-generating components mounted on the first substrate surface, but also the lead terminals exposed on the first substrate surface side of the discrete components mounted on the second substrate surface.

[0018] (Shape of support member) The support member is a cylindrical member having end faces of a predetermined polygonal or circular shape.

[0019] (Heat conduction member positioning part) The heat dissipation member has a positioning portion on its surface that indicates the position where the heat conduction member is to be placed.

[0020] (power supply) The present invention provides a power supply device, The heat dissipation structure of the wiring board described above; a wiring board having at least one heat-generating component mounted on a first board surface; Equipped with The heat dissipation structure is characterized by being assembled on the first substrate surface side of the wiring board.

[0021] (Manufacturing method of power supply device) The present invention provides the above-mentioned heat dissipation structure for a wiring board, a wiring board having at least one heat-generating component mounted on a first board surface; A method for manufacturing a power supply device comprising: a heat conducting member is disposed on the surface of the heat dissipation member at a predetermined position that can come into contact with the heat generating component of the wiring board, and a support member is disposed in a recess on the surface of the heat generating component; The wiring board is arranged so that the first board surface side of the wiring board is located on the surface side of the heat dissipation member on which the heat conduction member and the support member are arranged; The fixing member is inserted from the second substrate surface side opposite the first substrate surface of the wiring board into a through hole formed in the wiring board corresponding to the position of the support member and into a hollow portion of the support member, and the heat dissipation member and the wiring board are fixed by the fixing member.

[0022] Other features of the power supply device manufacturing method are basically the same as those described in the heat dissipation structure of the wiring board, and therefore will not be described here. [Effects of the Invention]

[0023] (Effect of the heat dissipation structure of the wiring board) The present invention is a heat dissipation structure for a wiring board having at least one heat-generating component mounted on a first board surface, comprising: a heat dissipation member arranged on the first board surface side of the wiring board; a support member which is a tubular member having a hollow portion extending from one end face to the other end face and arranged between the heat dissipation member and the wiring board so as to form a predetermined space between the heat dissipation member and the wiring board; a heat conduction member arranged in the space between the heat dissipation member and the wiring board so as to contact both the heat dissipation member and the heat-generating component; and a fixing member which is inserted into the hollow portion of the support member and fixes the heat dissipation member to the wiring board; the heat dissipation member has a recess on its surface facing the wiring board, the recess being recessed on the opposite side of the wiring board and having a bottom which has a larger area than the end face of the support member; and the support member is arranged with one of its end faces abutting the bottom of the recess, so that the height of the space between the heat dissipation member and the wiring board can be adjusted by the depth of the recess on the surface of the heat dissipation member, making it possible to adjust to the desired height even when a standard support member is used.

[0024] Furthermore, because the support member is positioned by the recess, the support member does not shift position when the fixing member is inserted into the hollow portion of the support member to fix the heat dissipation member and the wiring board, making it possible to assemble the heat dissipation structure to the wiring board easily and accurately. Furthermore, because the recess has a bottom (opening surface) that is larger in area than the end face of the support member, it is possible to easily position the support member in the recess.

[0025] In addition, when screws or the like are used as fixing members and the heat dissipation member and the wiring board are fixed by fastening, the number of times soldering is performed can be reduced, and the thermal stress applied to the components mounted on the wiring board can be reduced.

[0026] (Effect of discrete components mounted on the second board surface) The target wiring board is a wiring board having discrete components mounted on a second substrate surface opposite the first substrate surface, and the thermally conductive member is arranged to contact not only the heat dissipation member and the heat-generating components mounted on the first substrate surface, but also the lead terminals exposed on the first substrate surface of the discrete components mounted on the second substrate surface, so that if the discrete components mounted on the second substrate surface are heat-generating components, the heat generated by the discrete components on the second substrate surface can also be transferred to the heat dissipation member by the thermally conductive member and dissipated. Also, if the discrete components mounted on the second substrate surface are heat-dissipating components, the heat can be dissipated not only from the heat dissipation member but also from the discrete components on the second substrate surface.

[0027] (Effect of the shape of the support member) The support member is a cylindrical member with end faces of a specified polygonal or circular shape; if the support member is a polygonal cylindrical member, it is easy to hold, improving workability; if the support member is a circular cylindrical member, the shape of the bottom (opening surface) of the recess in the heat dissipation member can be made circular, making it easier to process the recess when manufacturing the heat dissipation member.

[0028] (Effect of the positioning part of the heat conductive member) Furthermore, since the heat dissipation member has a positioning portion on its surface that indicates the position where the heat conduction member is to be placed, it is possible to recognize the positions where not only the support member but also the heat conduction member is placed, and it is further possible to easily and accurately assemble the heat dissipation structure to the wiring board.

[0029] The effects of the power supply device and the method for manufacturing the power supply device are basically the same as those described for the heat dissipation structure of the wiring board, and therefore the description thereof will be omitted. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of a wiring substrate according to an embodiment. [Figure 2] FIG. 2 is an explanatory diagram showing an example of a heat sink according to an embodiment. [Figure 3] 1 is an explanatory diagram showing an example of a wiring board to which a heat dissipation structure according to an embodiment is assembled; [Figure 4] 1A to 1C are explanatory diagrams showing an example of a method for assembling a heat dissipation structure and a wiring board according to an embodiment. [Figure 5] FIG. 10 is an explanatory diagram showing a wiring board to which a conventional heat dissipation structure is assembled. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments of a heat dissipation structure for a wiring board, a power supply device including a wiring board on which the heat dissipation structure is assembled, and a manufacturing method thereof according to the present invention will be described. Note that the present invention is not limited to the following embodiments.

[0032] [Basic concept of the embodiment] First, the basic concept of the embodiment will be described. The embodiment generally relates to a heat dissipation structure for a wiring board having at least one heat-generating component mounted on a first board surface, and the scope of the invention extends to a power supply device including a wiring board with the heat dissipation structure assembled thereon and a manufacturing method thereof.

[0033] A "wiring board" is a board made of an insulating material such as glass epoxy resin, on which conductive wiring is provided on or inside the board. This includes various types of boards, such as single-sided boards with wiring on one board surface, double-sided boards with wiring on both board surfaces, and multilayer boards with wiring also provided inside the board. In the embodiments, the board surface on which heat-generating components that are the target of heat dissipation by the heat dissipation structure are mounted is referred to as the "first board surface," and the board surface opposite the first board surface is referred to as the "second board surface." Furthermore, a "heat-generating component" is a component mounted on the wiring board that is the target of heat dissipation, such as a switching element such as an FET. Naturally, the electrical and electronic components (mounted components) mounted on the wiring board will vary depending on the device that includes the wiring board, and the heat-generating components that are the target of heat dissipation by the heat dissipation structure will also vary depending on the device that includes the wiring board.

[0034] The "heat dissipation structure" includes a heat dissipation member, a support member, a heat conduction member, and a fixing member.

[0035] The "heat dissipation member" is a member for dissipating heat generated by heat-generating components, and is a member located on the first substrate side of the wiring board when the heat dissipation structure is assembled to the wiring board. The "heat dissipation member" may have any shape, but may be, for example, a heat dissipation plate made of a plate-like member or a heat dissipation plate with multiple fins on a plate-like member, as long as it has a shape that can dissipate heat. The material of the "heat dissipation member" may also be a material with excellent thermal conductivity, such as a metal heat dissipation member made of copper or aluminum, a ceramic heat dissipation member made of aluminum nitride or silicon nitride, or a graphite heat dissipation member made of carbon.

[0036] The "support member" is a cylindrical member with a predetermined polygonal or circular end face, for example, that is arranged between the heat dissipation member and the wiring board so as to form a predetermined space between them and has a hollow portion that penetrates from one end face to the other. The "support member" also includes, for example, a "spacer," which includes various spacers such as metal spacers made of brass or aluminum, and resin spacers made of polyacetal or ABS.

[0037] The "thermal conduction member" is a member that is placed in the space between the heat dissipation member and the wiring board so as to be in contact with both the heat dissipation member and the heat-generating component, and that conducts the heat generated by the heat-generating component to the heat dissipation member. Examples include a silicone-based sheet-like "heat dissipation sheet" that has high thermal conductivity and flexibility, and a silicone-based liquid "heat dissipation filler" that has high thermal conductivity. The "heat dissipation sheet" is a sheet with a predetermined flexibility, and its compression ratio in the height direction is determined by the height of the space between the heat dissipation member and the wiring board. The height of the space between the heat dissipation member and the wiring board is adjusted so that the compression ratio is sufficient to ensure thermal conductivity from the heat-generating component to the heat dissipation member, but does not distort the wiring board and damage the components mounted on the wiring board.

[0038] The "fixing member" is a member that is inserted into the hollow portion of the support member to fix the heat dissipation member and the wiring board, and is, for example, a screw, or a terminal that can be soldered or crimped to the wiring board or heat dissipation plate.

[0039] Furthermore, the number of "heat dissipation members," "support members," "thermal conduction members," and "fixing members" included in the "heat dissipation structure" is not necessarily limited to one, and may be multiple. For example, if two heat-generating components are mounted on the first substrate surface of the wiring board, the heat dissipation structure may be provided with separate "heat dissipation members" and "thermal conduction members" for each heat-generating component, or may be provided with a common "heat dissipation member" and "thermal conduction member." Furthermore, the heat dissipation structure may be provided with "support members" arranged in multiple locations, and "fixing members" inserted into one or more of the "support members."

[0040] In one embodiment, the heat dissipation member has a recess on the surface facing the wiring board, the recess is recessed on the opposite side of the wiring board, and has a bottom with a larger area than the end face of the support member, and the support member is positioned with one of its end faces abutting the bottom of the recess.

[0041] Here, as long as the bottom of the recess has a larger area than the end face of the support member and the end face of the support member can be arranged in contact with the bottom of the recess, the shape of the end face of the support member and the shape of the bottom (opening) of the recess are not limited to being the same, and the size of the bottom and opening of the recess are not limited to being the same. For example, if the end face shape of the support member is circular, the shape of the bottom (opening) is not limited to being circular, but may be other shapes such as a polygon or a truncated circle, and the size of the bottom and opening may be different, such as a truncated cone.

[0042] For this reason, in the heat dissipation structure of the embodiment, the height of the space between the heat dissipation member and the wiring board is not determined by the height of the support member, but by the difference between the height of the support member and the depth of the recess in the heat dissipation member. By adjusting the depth of the recess in the heat dissipation member, it is possible to adjust the height of the space between the heat dissipation member and the wiring board to any height. Even when standard spacers with heights in 0.5 mm or 1.0 mm increments are used, the height of the space between the heat dissipation member and the wiring board can be finely adjusted. Note that, although the adoption of the heat dissipation structure of the embodiment makes fine height adjustment possible even when standard spacers are used, this does not prevent the use of custom spacers or support members other than spacers as support members.

[0043] The recess also functions as a positioning element that indicates the placement position of the support member, and since the bottom (opening surface) of the recess has a larger area than the end face of the support member, the structure makes it easy to place the support member in the recess, making it possible to assemble the support member to the wiring board more easily and accurately than conventional heat dissipation structures in which the support member is assembled by abutting it against the surface of the heat dissipation member.

[0044] Furthermore, the wiring board to which the heat dissipation structure is to be assembled may be a wiring board having discrete components mounted on a second substrate surface opposite the first substrate surface. In this case, the thermally conductive member is arranged to contact not only the heat dissipation member and the heat-generating components mounted on the first substrate surface, but also the lead terminals exposed on the first substrate surface of the discrete components mounted on the second substrate surface. Here, the discrete components are lead-type components that are mounted in through holes such as through holes or non-through holes in the wiring board. Furthermore, the "discrete components" mounted on the second substrate surface may be either heat-generating components or heat-dissipating components.

[0045] In addition, the heat dissipation member may have a "positioning portion" on its surface that indicates the position where the heat conduction member is placed, and the "positioning portion" that indicates the position where the heat conduction member is placed may, for example, be a groove or protrusion formed around or part of the periphery of the area where the heat conduction member is placed.

[0046] The specific contents of the embodiment will be explained below by presenting examples. In the specific contents of the embodiment, the "wiring board" will be explained as "a wiring board in which switching elements are mounted as heat-generating components on a first substrate surface and a copper plate is mounted as a heat-dissipating component on a second substrate surface," the "heat dissipation member" of the heat dissipation structure will be explained as a "heat dissipation plate," the "support member" will be explained as a "spacer," the "thermal conduction member" will be explained as a "heat dissipation sheet," and the "fixing member" will be explained as a "screw."

[0047] [Specific details of the embodiment] The specific contents of the embodiment will be described separately as follows. a. Wiring board b. Heat dissipation structure c. A wiring board with a heat dissipation structure d. Heat dissipation structure and wiring board assembly method e. Modifications of the present invention

[0048] [a. Wiring board] First, a wiring board on which the heat dissipation structure is assembled will be described. In this description, reference will be made to Fig. 1, which shows an example of a wiring board according to an embodiment. Note that Fig. 1(A) shows the wiring board as viewed from the second substrate side, and Fig. 1(B) shows the wiring board as viewed from the first substrate side.

[0049] In addition, in the explanation of Figure 1, the Y direction (vertical direction) is defined as the second substrate surface being the upper surface and the first substrate surface being the lower surface, and the X direction (left-right direction) and Z direction (front-back direction) are defined as viewed from the second substrate surface as in Figure 1(A); that is, in Figure 1(B) viewed from the first substrate surface, the left and right are reversed.

[0050] The wiring board 10 has a switching element (semiconductor element) 12 mounted on a first substrate surface 1010 as a heat-generating component, a copper plate 14 mounted on a second substrate surface 1012 as a heat-dissipating component, and has through holes 1020 at two locations, the front right and the rear left, that penetrate from the first substrate surface 1010 to the second substrate surface 1012.

[0051] The switching element 12 is a component such as a surface-mounted FET or power transistor, and as shown in FIG. 1, for example, terminals are drawn out from a rectangular resin molded body, and the switching element 12 is mounted on the wiring board 10 by soldering each terminal to a wiring layer (the shaded area in FIG. 1) exposed on the first board surface 1010.

[0052] Furthermore, the copper plate 14 is a discrete component, and as shown in FIG. 1, for example, has two lead terminals 1410 extending downward from two positions on the upper left and right sides, and is mounted on the wiring board 10 by inserting the lead terminals 1410 into through holes formed in the wiring board 10 and soldering them to the wiring layer exposed on the first board surface 1010 (the shaded area in FIG. 1).

[0053] The components mounted on the wiring board 10 are not limited to the switching elements 12 and copper plates 14 shown in FIG. 1, but other electrical and electronic components such as resistors and capacitors may also be mounted, but are not shown.

[0054] Furthermore, through holes 1020 are holes for passing screws to fasten wiring board 10 and the heat sink together.

[0055] [b. Heat dissipation structure] Next, the heat dissipation structure will be described. In this description, in addition to Fig. 1, Fig. 2, which shows an example of a heat dissipation plate according to an embodiment, will be referred to. In Fig. 2, (A) shows the heat dissipation plate as seen from the surface, (B) shows a cross section of the recess, (C) shows a cross section of the recess when a spacer is placed and fastened with screws, and (D) and (E) show modified examples of the recess as seen from above. In Fig. 2, (B) and (C) show cross sections taken along the cutting line AA in (A).

[0056] In addition, in the description of Figure 2, the Y direction (vertical direction) is defined so that the surface of the heat sink is the upper surface, and the X direction (horizontal direction) and Z direction (front-rear direction) are defined in the same way as in Figure 1, and the X, Y, and Z directions in Figures 3 to 5 below are also defined in the same way as in Figures 1 and 2.

[0057] The heat dissipation structure includes a heat dissipation plate 20 as a heat dissipation member, a heat dissipation sheet 22 as a heat conduction member, a spacer 24 as a support member, and screws 26 as fixing members.

[0058] The heat sink 20 is a member for radiating heat generated by the switching elements 12 of the wiring board 10 into the air, and as shown in (A) of Figure 2, for example, has recesses 2010 at two locations on the front right and rear left of its surface corresponding to the positions of the through holes 1020 of the wiring board 10 through which the screws 24 are inserted, and also has positioning portions 2020 with L-shaped grooves formed in them that correspond to the two corners of the front right and rear left of the area where the heat sink sheet is placed.

[0059] The structure of the recess 2010 will correspond to the shape of the spacer 24 to be used, but in this embodiment, a round (cylindrical) spacer 24 is used, and as shown in Figure 2 (B), in addition to a groove whose bottom 2012 and opening surface are circular and have a diameter L1 and a depth H1 from the surface of the heat sink 20, it has a screw hole 2014 with a diameter L2 extending downward from approximately the center of the bottom 2012.

[0060] 2C, diameter L1 of the bottom and opening of recess 2010 is set to be larger than diameter L3 of spacer 24 so that a play equal to the difference between L1 and L3 is formed when the lower surface (end surface) of spacer 24 is placed in contact with bottom 2012 of recess 2010, thereby facilitating placement of spacer 24 in recess 2010. If the play is too large, the range of movement of spacer 24 within recess 2010 becomes wider, making it difficult to determine the position of spacer 24 and deteriorating the workability of subsequent fastening and fixing of wiring board 10 and heat sink 20 using screws 26. Therefore, diameter L1 is set so that the play is, for example, about 5 mm.

[0061] The shape of the bottom 2012 (opening surface) of the recess 2010 is not limited to a circular shape, and may be a polygonal shape such as a square shape shown in Fig. 2(D) or a shape other than a circle such as a parted circle shape shown in Fig. 2(E). Furthermore, the diameters of the bottom 2012 and the opening surface of the recess 2010 do not necessarily need to be the same, and may be different sizes as long as a spacer 24 with a diameter L3 can pass through the opening surface and an end face of the spacer 24 can abut against the bottom 2012.

[0062] Furthermore, in the embodiment, the depth H1 of the recess 2010 (the depth from the opening surface to the bottom 2012) is one of the parameters that determine the height of the area between the wiring board 10 and the heat sink 20, and since the recess 2010 is formed by processing the surface of the heat sink 20 when manufacturing the heat sink 20 by mold molding or the like, the depth H1 can be finely adjusted, for example, in increments of 0.1 mm, which allows for finer adjustment than the height adjustment achieved with a standard spacer 24, whose height is in increments of 0.5 mm or 1.0 mm.

[0063] 2B and 2C, the screw holes 2014 may be holes that penetrate all the way to the rear surface (bottom surface) of the heat sink 20, or may be holes with a predetermined depth that do not penetrate all the way to the rear surface of the heat sink 20.

[0064] The heat dissipation sheet 22 is a member that conducts heat generated by the switching elements 12 to the heat dissipation plate 20 and the copper plate 14, and is placed at a position determined by the positioning portion 2020 of the heat dissipation plate 20 so as to be in contact with the switching elements 12 located on the first substrate surface 1010 side and the lead terminals 1410 of the copper plate 14, and on the wiring board 10 side, is placed in the area indicated by the dotted line in (B) of Fig. 1. Furthermore, by mounting the components so that the areas of the switching elements 12 and the copper plate 14 overlap in the left-right direction of the wiring board 10, the size of the heat dissipation sheet 22 does not become large.

[0065] 2C, the spacer 24 has a hollow portion that penetrates from the upper surface (one end surface) to the lower surface (the other end surface) for inserting the screw 26. In the embodiment, the diameter of the hollow portion is the same as the diameter L2 of the screw hole 2014 of the recess 2010, but it does not have to be the same diameter L2 as the screw hole 2014 as long as it is large enough to insert the screw 26.

[0066] The screws 26 are members that are inserted into the hollow portions of the spacers 24 and screwed into the screw holes 2014 in the recesses 2010 of the heat sink 20, thereby fastening the wiring board 10 and the heat sink 20 together.

[0067] [c. Wiring board with heat dissipation structure] Next, a wiring board on which a heat dissipation structure is assembled will be described. In this description, reference will be made to Fig. 3, which shows an example of a wiring board on which a heat dissipation structure according to an embodiment is assembled. Fig. 3A shows the wiring board on which a heat dissipation structure is assembled, as viewed from the second substrate side, and Fig. 3B shows a cross section as viewed from the front. Fig. 3B shows a cross section taken along cutting line BB in Fig. 3A.

[0068] When assembling the heat dissipation structure to the wiring board 10, the heat dissipation sheet 22 is positioned in accordance with the positioning portion 2020 of the heat dissipation plate 20, which will be in contact with the switching element 12 and the lead terminal 1410 of the copper plate 14 located on the first board surface 1010 side of the wiring board 10, and spacers 24 are placed in each of the recesses 2010 of the heat dissipation plate 20. Screws 26 are inserted from the second board surface 1012 side of the wiring board 10 into the through holes 1020 and the hollow portions of the spaces 24, and the screws 26 are screwed into the screw holes 2014 of the recesses 2410 to fasten and fix them.

[0069] Here, when the heat dissipation structure is assembled to the wiring board 10, the height H0 of the space formed between the wiring board 10 and the heat sink 20 is the height H2 of the spacer 24 minus the depth H1 of the recess. As mentioned above, the depth H1 of the recess can be finely adjusted, for example, in increments of 0.1 mm, so the height H0 can be finely adjusted even when a standard spacer 24 is used.

[0070] When the heat dissipation structure is assembled to wiring board 10, heat dissipation sheet 22 is compressed in the height direction (vertical direction), and the compression rate is determined by the thickness of heat dissipation sheet 22 and the height H0 of the space formed between wiring board 10 and heat sink 20. For this reason, height H0 of the space formed between wiring board 10 and heat sink 20 is basically adjusted to be lower than the thickness of heat dissipation sheet 22, and is adjusted to an appropriate compression rate that ensures sufficient thermal conductivity from switching elements 12 to heat sink 20 and copper plate 14, and does not distort wiring board 10 and damage the components mounted on wiring board 10.

[0071] Furthermore, by using a highly flexible sheet for the heat dissipation sheet 22, it is possible to make contact without gaps even in areas where there are height differences with the surrounding area, such as near the lead terminals 1410 of the copper plate 14 and near the terminals of the switching element 12, thereby enabling the heat generated from the switching element 12, which is a heat-generating component, to be efficiently conducted to the heat dissipation plate 20 and the copper plate 14.

[0072] [d. Heat dissipation structure and wiring board assembly method] Next, a method for assembling the heat dissipation structure and the wiring board will be described. In this description, reference will be made to FIG. 4, which shows an example of a method for assembling the heat dissipation structure and the wiring board in an embodiment. Note that (A) in FIG. 4 shows the first step, (B) the second step, (C) the third step, (D) the fourth step, and (E) the fifth step. Furthermore, the assembling method is not limited to the assembling method shown in FIG. 4, and any assembling method can be used as long as it can assemble the heat dissipation structure to the mounting board.

[0073] In the first step, as shown in FIG. 4(A), the heat sink 20 is set in the assembly jig 30 with the surface having the recessed portion 2010 and the positioning portion 2020 facing upward.

[0074] Next, in the second step, as shown in Fig. 4(B), the heat dissipation sheet 22 is placed in accordance with the positioning portions 2020 of the heat dissipation plate 20, and in the third step, as shown in Fig. 4(C), spacers 24 are placed in each of the recesses 2010 of the heat dissipation plate 20. In addition, an adhesive layer is provided on the surface of the heat dissipation sheet 22 facing the heat dissipation plate 20, so that the heat dissipation sheet 22 is attached to the heat dissipation plate 20 when the heat dissipation sheet 22 is placed on the surface of the heat dissipation plate 20 in the second step.

[0075] Next, as a fourth step, as shown in (D) of Figure 4, the wiring board 10, on which components including the switching elements 12 and the copper plate 14 have been mounted, is placed with the second board surface 1012 facing up and the through hole 1020 aligned with the position of the space 24, and as a fifth step, as shown in (E) of Figure 5, a screw 26 is inserted from the second board surface 1012 side of the wiring board 10 through the through hole 1020 of the wiring board 10 and the hollow portion of the space 24, and fastened by screwing it into the screw hole 2014 of the recess 2010 of the heat sink 20, thereby completing the assembly of the heat dissipation structure to the wiring board 10.

[0076] [d. Modifications of the present invention] The heat dissipation structure for a wiring board, the power supply device, and the method of manufacturing the same according to the present invention are described below. In addition to the above-described embodiments, the heat dissipation structure for a wiring board, the power supply device, and the method of manufacturing the same according to the present invention also include the following modifications.

[0077] (Shape of recess and shape of spacer) In the above embodiment, the spacer 24 is a round spacer, and the opening surface and the bottom 2012 of the recess 2010 of the heat sink 20 are circular in shape, but this is not limited to this. In addition to round spacers, standard spacers also include spacers with polygonal end faces, such as square or hexagonal, and when these polygonal spacers are used, the shapes of the opening surface and the bottom 2012 of the recess 2010 of the heat sink 20 will also change to match the shape of the end face of the spacer used.

[0078] (heat-generating components and heat-dissipating components) In the above embodiment, the switching elements 12 are mounted as heat-generating components on the first substrate surface 1010 of the wiring board 10, and the copper plate 14 is mounted as a heat-dissipating component on the second substrate surface 1012, but this is not limiting. For example, instead of a heat-dissipating component, a discrete switching element may be mounted as a second heat-generating component on the second substrate surface 1012. Furthermore, the heat-generating components and heat-dissipating components are not limited to the switching elements 12 and the copper plate 14, and may be any other components.

[0079] (others) Furthermore, the present invention includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited to the numerical values ​​shown in the above embodiments. [Explanation of symbols]

[0080] 10, 100: Wiring board 1010, 101: First board surface 1012, 102: Second board surface 1020:Through hole 12, 120: Switching element 14, 140: Copper plate 1410, 141: Lead terminal 20, 200: Heat sink 2010: Recess 2012: Bottom 2014: screw holes 2020: Positioning section 22, 220: Heat dissipation sheet 24, 240: Spacer 26, 260: Screws 280: Terminal 290: Solder 30: Assembly jig

Claims

1. A heat dissipation structure for a wiring board having at least one heat-generating component mounted on a first board surface, a heat dissipation member disposed on a first substrate surface side of the wiring substrate; a support member that is a cylindrical member having a hollow portion that penetrates from one end surface to the other end surface, and that is disposed between the heat dissipation member and the wiring board so as to form a predetermined space between the heat dissipation member and the wiring board; a heat conduction member disposed in the space between the heat dissipation member and the wiring board so as to be in contact with both the heat dissipation member and the heat-generating component; a fixing member that is inserted into a hollow portion of the support member and fixes the heat dissipation member and the wiring board; Equipped with the heat dissipation member has a recess on a surface facing the wiring board, the recess is recessed on the opposite side of the wiring substrate and has a bottom having an area larger than that of the end face of the support member; The heat dissipation structure for a wiring board, wherein the support member is disposed with one end face thereof abutting against the bottom of the recess.

2. 2. The heat dissipation structure for a wiring board according to claim 1, The target wiring board is a wiring board in which discrete components are mounted on a second substrate surface opposite to the first substrate surface, A heat dissipation structure for a wiring board, characterized in that the thermal conduction member is arranged so as to contact not only the heat dissipation member and the heat-generating components mounted on the first substrate surface, but also lead terminals exposed on the first substrate surface side of discrete components mounted on the second substrate surface.

3. 2. The heat dissipation structure for a wiring board according to claim 1, The heat dissipation structure for a wiring board is characterized in that the support member is a tubular member having end faces of a predetermined polygonal or circular shape.

4. 2. The heat dissipation structure for a wiring board according to claim 1, The heat dissipation structure for a wiring board, wherein the heat dissipation member has a positioning portion on the surface that indicates a position where the heat conduction member is to be placed.

5. A heat dissipation structure for a wiring board according to any one of claims 1 to 4; a wiring board having at least one heat-generating component mounted on a first board surface; Equipped with a power supply device, wherein the heat dissipation structure is assembled on the first substrate surface side of the wiring board;

6. a heat dissipation structure for a wiring board according to claim 1; a wiring board having at least one heat-generating component mounted on a first board surface; A method for manufacturing a power supply device comprising: the heat conducting member is disposed at a predetermined position on the surface of the heat dissipation member so as to be in contact with the heat generating component of the wiring board, and the support member is disposed in a recess on the surface of the heat generating component; the wiring board is arranged so that a first board surface side of the wiring board is located on a surface side of the heat dissipation member on which the heat conduction member and the support member are arranged; A method for manufacturing a power supply device, characterized in that the fixing member is inserted from the second substrate surface side opposite the first substrate surface of the wiring board into a through hole formed in the wiring board corresponding to the position of the support member and into a hollow portion of the support member, and the heat dissipation member and the wiring board are fixed by the fixing member.

7. 7. A method for manufacturing a power supply device according to claim 6, comprising: the wiring board has discrete components mounted on the second substrate surface, A method for manufacturing a power supply device, characterized in that the predetermined position on the surface of the heat dissipation member where the heat conduction member is placed is a position that can contact a heat-generating component mounted on the first substrate surface and a lead terminal exposed on the first substrate surface side of a discrete component mounted on the second substrate surface.

8. 7. A method for manufacturing a power supply device according to claim 6, comprising: the heat dissipation member has a positioning portion on the surface that indicates a position where the heat conduction member is to be placed, The method for manufacturing a power supply device, wherein the heat conduction member is placed at a position indicated by the positioning portion.

Images