JP6279397B2 - Heat dissipation structure and method of removing heat dissipation structure - Google Patents

Description

  The present invention relates to a heat dissipation structure that includes a heat sink and a spacer that attaches the heat sink to the wiring board, and that radiates heat from the wiring board, and a method for removing the heat dissipation structure.

  Conventionally, in order to dissipate heat generated in a wiring board including heat generated in an electronic component existing on the wiring board, a method of attaching a heat sink to the wiring board through, for example, a spacer has been taken. In this method, when a plurality of wiring boards are juxtaposed, a sub heat sink is attached to each wiring board via a spacer, while each sub heat sink is interposed with a heat transfer material such as heat radiation grease, for example. The heat-dissipating area is increased by attaching it to a common large main heat sink.

JP 2004-122343 A

  In such a conventional heat dissipation structure, at the time of disassembly, the sub heat sink is detached from the main heat sink by pulling the wiring board to which the sub heat sink is attached via the spacer in a direction away from the main heat sink, and the Can be removed along with the heat sink. However, since the heat radiation grease between the sub heat sink and the main heat sink has a high viscosity, if the attachment strength of the sub heat sink to the wiring board through the spacer is low, the sub heat sink does not leave the main heat sink and comes off the wiring board. There is a possibility of damaging the wiring board or an electronic component extending over both the wiring board and the sub heat sink. Therefore, a method of increasing the number of spacers is employed in order to ensure the mounting strength. However, when the number of spacers increases, a space for attaching an increased amount of spacers on the wiring board and an insulating space around the space are required, and the dimensions of the wiring board increase. In addition, the configuration of the wiring board becomes complicated, for example, the wiring pattern has to be routed to secure the space. In Patent Document 1, a sub heat sink and a main heat sink are not used, but a technique in which a heat sink is attached to a power element is disclosed.

  Then, an object of this invention is to provide the thermal radiation structure which can suppress the increase in the dimension of a wiring board, and complication, and the removal method of a thermal radiation structure.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. That is, the heat dissipation structure according to the present invention has a plate-like sub heat sink whose one main surface adheres to the main heat sink to dissipate the wiring board, and a spacer fixed to the sub heat sink. A heat dissipating structure, the other main surface of the heat sink being opposed to the wiring board and being attached to the wiring board via the spacer, wherein the spacer is provided with a screw hole penetrating the heat sink. The first screw body inserted through the insertion hole is screwed into the screw hole of the spacer, so that the sub heat sink is attached to the wiring board, and the screw hole of the spacer is the one main part of the sub heat sink. It is exposed on the surface.

  According to this configuration, since the screw hole of the spacer is exposed on one main surface of the sub heat sink, for example, a removal screw body longer than the spacer is inserted from the insertion hole of the wiring board into the screw hole of the spacer. By screwing, a pressing force is applied to the main heat sink by the tip of the removing screw body, and the sub heat sink is detached from the main heat sink against the adhesive force. This eliminates the need for pulling the wiring board away from the main heat sink by pulling the wiring board away from the main heat sink, so that the sub heat sink does not come off the wiring board due to pulling. Accordingly, the strength of attaching the sub heat sink to the wiring board is not a problem, and it is not necessary to increase the number of spacers between the wiring board and the sub heat sink. Therefore, an increase in the size of the wiring board can be suppressed, and it is also possible to avoid a complicated configuration of the wiring board.

  The method for removing the heat dissipation structure according to the present invention is a method for removing the heat dissipation structure from the main heat sink, wherein the first screw body is extracted from the wiring board and the spacer, and the removal screw body is longer than the spacer. Is inserted through the insertion hole of the wiring board and screwed into the screw hole of the spacer, thereby applying a pressing force to the main heat sink by the distal end portion of the removal screw body, and resisting the adhesive force. A heat sink is detached from the main heat sink.

  According to this method of removing the heat dissipation structure, the sub heat sink can be easily detached from the main heat sink by screwing the removal screw body into the screw hole of the spacer.

  The sub heat sink preferably includes a heat-dissipating fastener for attaching the electronic component having a lead wire soldered to a wiring pattern on the wiring board. With this configuration, heat generated in the electronic component propagates from the sub heat sink toward the main heat sink and is dissipated, and in addition, heat is also dissipated in the fastener itself, so that the heat dissipation efficiency of the electronic component is improved. In addition, when the sub heat sink is detached from the main heat sink, the sub heat sink does not come off the wiring board, so that the electronic components that straddle both the wiring board and the sub heat sink are not damaged.

  A tool insertion hole is formed in the wiring board at a position facing a head of a second screw body that screw-connects the sub heat sink to the main heat sink, and the second screw of the tool inserted through the tool insertion hole It is preferable to have access to the body. Since the second heat sink prevents the sub heat sink from coming off from the main heat sink, heat can be reliably radiated from the sub heat sink to the main heat sink. Here, the tool can be inserted into the tool insertion hole and engaged with the head of the second screw body, and the second screw body can be operated to tighten and loosen, so the sub heat sink is attached to the wiring board. In this state, the sub heat sink can be connected to and disconnected from the main heat sink, so that the operability is good.

  According to the present invention, it is possible to suppress an increase in size and complexity of the wiring board.

It is a perspective view of the wiring board with which the heat dissipation structure concerning one Embodiment of this invention was attached. It is the side view seen from the II-II direction of FIG. (A) is a partial perspective view of the sub heat sink of the heat dissipation structure, (B) is a rear view seen from the III-III direction of FIG. 1, and (C) is a longitudinal sectional view of the main part around the fitting hole. It is. It is the side view seen from the IV-IV direction of FIG. It is a top view of the wiring board and heat dissipation structure concerning the embodiment. It is a side view corresponding to FIG. 4 showing a mode that the sub heat sink of the thermal radiation structure attached to the wiring board which concerns on the same embodiment is removed from a main heat sink.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts, and the description thereof will be omitted as appropriate unless otherwise specified.

  FIG. 1 shows a power supply device 1 which is an example of an electric device provided with a heat dissipation structure HS according to an embodiment of the present invention. The heat dissipation structure HS has a plate-like sub heat sink 2 and a spacer 22, and is attached to the lower surface of the wiring board 3. The sub heat sink 2 is attached to a plate-like main heat sink 4 below the sub heat sink 2, and heat from the sub heat sink 2 is conducted to the main heat sink 4. The main heat sink 4 has a larger planar dimension than the sub heat sink 2, and one or more other power supply devices are arranged side by side along the longitudinal direction X of the main heat sink 4. Thereby, the heat of the electronic components arranged on the wiring board 3 and the wiring board 3 is radiated to the surrounding atmosphere via the sub heat sink 2 and the main heat sink 4. Here, the heat dissipation structure HS and the sub heat sink 2 may be one.

  As shown in FIG. 2, the wiring board 3 has various electronic circuit components 30 mainly on the surface opposite to the sub heat sink 2. On the other hand, the wiring board 3 has an electronic component 33 which is a power element such as a field effect transistor (FET) and an insulated gate bipolar transistor (IGBT) on the back surface on the sub heat sink 2 side. The electronic component 33 may be an electronic circuit component other than the power element. In the present embodiment, as an example, two types of electronic components 33 </ b> A and 33 </ b> B are each mounted on the back surface of the wiring board 3. The electronic components 33A, 33A, 33B, and 33B are arranged side by side along the longitudinal direction X1 of the wiring board 3. In the present embodiment, the longitudinal direction X1 is orthogonal to the longitudinal direction X of the main heat sink 4.

  In the present embodiment, the electronic components 33A and 33B have main body portions 34A and 34B (see FIG. 3 described later) having a substantially rectangular parallelepiped shape. Further, the electronic component 33A has two lead wires 35A, and the electronic component 33B has three lead wires 35B, and these lead wires 35A and 35B are soldered to the wiring pattern on the wiring board 3. The electronic components 33A and 33B are attached to the wiring board 3. The lead wires 35A and 35B of the electronic components 33A and 33B are bent substantially at right angles in the middle, and the main surfaces of the main parts of the electronic components 33A and 33B are substantially parallel to the wiring board 3.

  The wiring board 3 shown in FIG. 1 is provided with an insertion hole 32 a for screwing the spacer 22 interposed between the sub heat sink 2 and the wiring board 3. While the spacer 22 is fixed to the sub heat sink 2 by a method described later, the first screw body 32 inserted through the insertion hole 32a is screwed into the screw hole 22a (see FIG. 3 described later) of the spacer 22 and tightened. The sub heat sink 2 is attached to the wiring board 3 via the spacer 22.

  As shown in FIG. 3A, the spacer 22 has, for example, a cylindrical shape, and is formed with a screw hole 22a extending along the axial direction thereof. The shape of the spacer 22 is not limited to a cylindrical shape, and may be a prism shape, a truncated cone shape, or a truncated pyramid shape. In the present embodiment, the number of spacers 22 is one, but a plurality of spacers may be used.

  The sub heat sink 2 is made of, for example, aluminum, and one main surface 2a serving as a lower surface is opposed to the main heat sink 4 made of, for example, aluminum. More specifically, one main surface 2a adheres to the main heat sink 4 via a heat dissipating grease 11 having a viscosity such as silicon grease. The heat dissipating grease is used for improving the heat dissipating property from the sub heat sink 2 to the main heat sink 4, and ceramic grease or silver grease can be used in addition to silicon grease. Further, the sub heat sink 2 has the other main surface 2b which is the upper surface facing the wiring board 3, and the spacer 22 shown in FIG. 3B is fixed, and the main surface 2a, It is attached to the wiring board 3 via the spacer 22 so that 2b is substantially parallel. Part of heat generated in the wiring board 3 propagates from the sub heat sink 2 toward the main heat sink 4 through the spacer 22.

  As shown in FIG. 3C, the sub heat sink 2 is provided with a fitting hole 23 penetrating therethrough, and the base end portion of the spacer 22 opposite to the wiring board 3 is press-fitted into the fitting hole 23. Are mated. A knurl 22b is formed on the outer periphery of the base end, and the knurl 22b bites into the inner peripheral surface of the fitting hole 23 during press-fitting so that the spacer 22 does not rotate relative to the sub heat sink 2 and The spacer 22 is fixed to the heat sink 2 so as not to come off in the axial direction. In this fixed state, the screw hole 22 a of the spacer 22 is exposed on one main surface 2 a of the sub heat sink 2. More specifically, since the length of the first screw body 32 is shorter than the length of the spacer 22 and the tip 32b of the first screw body 32 remains inside the screw hole 22a of the spacer 22, the screw hole 22a is in an open state. is there.

  The sub heat sink 2 is connected to the main heat sink 4 by a second screw body 21 as shown in FIG. Thereby, since the coupling between the sub heat sink 2 and the main heat sink 4 becomes strong, heat can be reliably radiated from the sub heat sink 2 to the main heat sink 4. The screw connection structure by the second screw body 21 is general, and the second screw body 21 (FIG. 2) is inserted into the screw insertion hole 21a provided in the sub heat sink 2 shown in FIG. Screw into the provided screw hole. In the wiring board 3, a tool insertion hole 31 is formed at a position facing the head of the second screw body 21 (FIG. 2) that screws the sub heat sink 2 to the main heat sink 4. The tool insertion hole 31 allows access to the second screw body 21, and a tool such as a screwdriver for operating the second screw body 21 is inserted into the tool insertion hole 31, so that the head of the second screw body 21 is inserted. The second screw body 21 can be rotated by engaging with. Therefore, since the sub heat sink 2 can be connected to and disconnected from the main heat sink 4 with the sub heat sink 2 attached to the wiring board 3, the operability is good.

  Further, the sub heat sink 2 has a fastener 24 (24A, 24B) for attaching an electronic component 33 (33A, 33B) attached to the wiring board 3 shown in FIG. The fastener 24 is made of stainless steel, for example, and has high heat dissipation and thermal conductivity. The fastener 24 may be made of a material having high thermal conductivity such as iron, aluminum, or copper, in addition to stainless steel. Further, as shown in FIG. 3A, each fastener 24 has, for example, a crank-shaped cross section in the longitudinal direction, and is screwed to the sub heat sink 2 by a screw body 241. The main body 34A of the electronic component 33A is pressed against the sub heat sink 2 and fixed by the fastener 24A, and the main body 34B of the electronic component 33B is pressed and fixed to the sub heat sink 2 by the fastener 24B. .

  In addition to the heat generated from the electronic component 33 propagating from the sub heat sink 2 to the main heat sink 4 due to the pressing of the main body 34 of the electronic component 33 to the sub heat sink 2 by the fastener 24, the fastener Since the heat is also dissipated by the 24 itself, the heat dissipation efficiency of the electronic component 33 is improved. Here, even if the electronic component 33 soldered to the wiring board 3 is fixed to the sub heat sink 2 by the fastener 24, the sub heat sink 2 is not detached from the wiring board 3 as described later. Is removed from the main heat sink 4, the electronic component 33 extending over both the wiring board 3 and the sub heat sink 2 is not damaged.

  A first insulating sheet 25 (25A, 25B) made of, for example, silicon is wound between the fastener 24 (24A, 24B) and the main body 34 (34A, 34B) of the electronic component 33 (33A, 33B). May be. The first insulating sheet 25 provides electrical insulation between the electronic component 33 and the metal fastener 24 and between the electronic component 33 and the sub heat sink 2. Furthermore, since the first insulating sheet 25 has thermal conductivity, heat propagation to the fastener 24 and the sub heat sink 2 generated by the electronic component 33 is not hindered.

  As shown in FIG. 4, a second insulating sheet 26 made of a resin such as polycarbonate may be interposed between the sub heat sink 2 and the wiring board 3. The second insulating sheet 26 is shown by a solid line in FIG. 3B or the like, but is shown by a broken line in FIG. 3A for ease of viewing. Since the lead wire of the electronic circuit component 30 soldered to the wiring pattern of the wiring substrate 3 protrudes from the back surface of the wiring substrate 3 on the sub heat sink 2 side, the electronic component 33 and the wiring are connected by the second insulating sheet 26. This is preferable because it can electrically insulate between the substrate 3, that is, between the electronic component 33 and the lead wire of the electronic circuit component 30 included in the wiring substrate 3. Since the second insulating sheet 26 exists between the sub heat sink 2 and the wiring board 3, the second insulating sheet 26 is inserted through the spacer 22 indicated by the dashed ellipse in FIG. A through hole 26a is provided.

  As shown by a rectangular broken line in FIG. 5, the sub heat sink 2 in which the four electronic components 33 </ b> A and 33 </ b> B are arranged along the longitudinal direction X <b> 1 of the sub heat sink 2 and fastened by the fasteners 24 </ b> A and 24 </ b> B Located on the side.

  Next, a method for removing the heat dissipation structure from the main heat sink will be described. First, a tool is inserted from the tool insertion hole 31 shown in FIG. 1 to remove the second screw body 21, and the screw connection between the sub heat sink 2 and the main heat sink 4 is released. Subsequently, the first screw body 32 is loosened and removed from the wiring board 3 and the spacer 22. Next, the removal screw body 40 longer than the spacer 22 and the first screw body 32 is inserted from the insertion hole 32 a of the wiring board 3 and screwed into the screw hole 22 a of the spacer 22.

  Next, as shown in FIG. 6, the distal end portion 40 a of the removal screw body 40 is protruded from the spacer 22 and the sub heat sink 2 by screwing the removal screw body 40 into the screw hole 22 a of the spacer 22. As a result, the projecting tip 40 a applies a pressing force to the main heat sink 4, so that the sub heat sink 2 is separated from the main heat sink 4 against the adhesive force of the sub heat sink 2 that adheres to the main heat sink via the heat radiation grease 11. Will be withdrawn.

  According to the heat dissipation structure HS and the method for removing the heat dissipation structure HS having the above-described configuration, the screw hole 22a of the spacer 22 is exposed on the one main surface 2a of the sub heat sink 2, so that it is longer than the spacer 22, for example. The removal screw body 40 is inserted into the insertion hole 32a of the wiring board 3 shown in FIG. 1 and screwed into the screw hole 22a of the spacer 22 of FIG. The sub heat sink 2 is detached from the main heat sink 4 against the adhesive force by applying a pressing force. As a result, there is no need to pull the wiring board 3 away from the main heat sink 4 by pulling the wiring board 3 away from the main heat sink 4, so that the sub heat sink 2 is detached from the wiring board 3 by pulling the wiring board 3. Nothing will happen. Therefore, the strength of attachment of the sub heat sink 2 to the wiring board 3 does not matter, and it is not necessary to increase the number of spacers 22 between the wiring board 3 and the sub heat sink 2 to improve the attachment strength. Thus, since the number of the spacers 22 is small, an increase in the dimension of the wiring board 3 can be suppressed, and the configuration of the wiring board 3 can be prevented from becoming complicated.

  In order to remove the sub heat sink from the main heat sink on the sub heat sink without using the spacer whose screw hole is exposed on the one main surface of the sub heat sink and the removing screw body inserted into the screw hole. A screw hole dedicated to the removal screw body may be provided separately.

  The present invention is not limited to the above-described embodiments, and various additions, modifications, or deletions are possible within the scope not departing from the gist of the present invention. Therefore, such a thing is also included in the scope of the present invention. For example, one spacer 22 is sufficient, but two or three spacers 22 may be used when four spacers are normally used.

2 Sub-heatsink 2a One main surface 2b The other main surface 21 Second screw body 22 Spacer 22a Screw hole 24, 24A, 24B Heat dissipating fastener 3 Wiring board 31 Tool insertion hole 32 First screw body 32a Insertion hole 33, 33A , 33B Electronic parts 35, 35A, 35B Lead wire 4 Main heat sink 40 Removal screw body 40a Tip portion HS Heat dissipation structure

Claims (4)

One main surface has a plate-like sub heat sink that adheres to the main heat sink and dissipates heat from the wiring board, and a spacer fixed to the sub heat sink, and the other main surface of the sub heat sink is attached to the wiring board. A heat dissipating structure that faces and is attached to the wiring board via the spacer,
A threaded hole is formed through the spacer,
The sub-heat sink is attached to the wiring board by screwing the first screw body inserted into the insertion hole provided in the wiring board into the screw hole of the spacer,
The screw hole of the spacer is exposed on the one main surface of the sub heat sink;
Heat dissipation structure. In claim 1,
The sub heat sink includes a heat dissipating fastener for attaching an electronic component to which a lead wire is soldered to a wiring pattern on the wiring board.
Heat dissipation structure. In claim 1 or 2,
A tool insertion hole is formed in the wiring board at a position facing a head of a second screw body that screw-connects the sub heat sink to the main heat sink, and the second screw of the tool inserted through the tool insertion hole Access to the body is possible,
Heat dissipation structure. A method of removing the heat dissipation structure according to claim 1 or 2 from the main heat sink,
The first screw body is extracted from the wiring board and the spacer, and a screw body for removal longer than the spacer is inserted through the insertion hole of the wiring board and screwed into the screw hole of the spacer, thereby removing the first screw body. A pressing force is applied to the main heat sink by the tip of the screw body, and the sub heat sink is detached from the main heat sink against the adhesive force.
How to remove the heat dissipation structure.

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