JP4413850B2 - Heat dissipation structure of board storage box - Google Patents

Description

  The present invention relates to a heat dissipation structure for a board storage box for storing a circuit board having an electric circuit that handles a large current such as a power supply circuit.

  When a circuit board equipped with a power supply circuit or the like is mounted on a vehicle, it is generally mounted in a state of being housed in a box. However, when a circuit board equipped with an electric circuit that handles a large current such as a power supply circuit is accommodated in a box, the amount of heat generated by the circuit board is very large, and thus sufficient consideration must be given to heat dissipation.

  As a conventional example in which countermeasures are taken, a heat radiation fin is directly attached to a heat generating component, and the heat radiation fin is exposed to the outside of the box to improve heat dissipation (for example, Patent Documents). 1).

  As another conventional example, the outer surface of the box body to which the circuit board is attached in a state where heat conduction is possible on the inner side surface is used as a heat radiating surface, and further, heat conduction from the mounting portion of the box body to the vehicle body, The thing which aimed at heat dissipation is proposed (for example, refer patent document 2).

  FIG. 3 is an exploded longitudinal sectional view showing a heat dissipation structure of a substrate storage box which is an example of such a kind. The heat dissipation structure includes a box body 50 in which the circuit board 1 to be radiated is accommodated, a board support portion 54 that supports the circuit board 1 in a state capable of conducting heat in the box body 50, and the box body 50. And a flange-shaped mounting portion 60 for mounting the box body 50 to a vehicle body (not shown).

  The box 50 includes an aluminum die-cast box main body (base) 52 and an aluminum flat lid 53 that closes an opening surface of the box main body 52, and is attached to the vehicle body outside the box main body 52. The part 60 is extended integrally. The box 50 is attached to the vehicle body by bringing the bottom surface 60a of the attachment portion 60 to the vehicle body into close contact with the vehicle body and tightening a screw into an insertion hole 61 formed in the attachment portion 60 in this state.

  A substrate support 54 is provided on the inner side surface of the box main body 52 by forming a step portion that is one step higher than the inner bottom surface 52 a of the box main body 52. An attachment surface 55 for the lid 53 is provided at the upper end of the side wall of the box body 52. Screw holes 56 and 57 are respectively provided in the mounting surface 55 of the substrate support portion 54 and the lid 53. When the circuit board 1 is stored in the box body 50, the circuit board 1 is attached via the heat conductive sheet 55. The circuit board 1 is attached to the board support part 54 by placing it on the board support part 54 and screwing the screw 68 into the screw hole 56 of the board support part 54 from above the circuit board 1 in this state.

  Next, the lid body 53 is placed on the attachment surface 55 at the upper end of the box body 52, and the screw 69 is screwed into the screw hole 57 of the attachment surface 55 of the lid body 53 from above the lid body 53. Attached to the main body 52. And the attachment structure 60 to the vehicle body of the box 50 which accommodated the circuit board 1 in that way is attached to a vehicle body with a screw (not shown), and the heat dissipation structure of a board | substrate storage box is completed.

  In such a state of attachment, the heat generated in the circuit board 1 is transmitted to the board support part 54 via the heat conductive sheet 58 and passes from the board support part 54 through the wall of the box body 50 to the attachment part 60 to the vehicle body. It is transmitted and escapes from the mounting portion 60 to the vehicle body.

JP 2002-325336 A JP-A-2005-117878

  By the way, in the thing of patent document 1, many heat radiation fins must be provided and the heat radiation area must be ensured, and there exists a problem that it cannot fully respond to the need for size reduction. In addition, heat dissipation can be achieved when the ambient temperature of the installation environment is low, but sufficient heat dissipation is possible when installed in a place where the ambient temperature is high, such as where the engine room is susceptible to heat sources. There is a possibility that it can not be exhibited.

  Moreover, the thing of patent document 2 cannot expect the heat dissipation by heat conduction very much unless the temperature difference of a circuit board and a box is large. For example, in the example of FIG. 3, when the lid 53 made of an aluminum plate is affected by heat in the engine room, the heat is transferred from the wall of the box 50 to the substrate support 54, thereby Since the temperature difference of the circuit board 1 becomes small, there is a problem that the heat dissipation performance due to heat conduction is lowered.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a heat dissipation structure for a substrate storage box that improves heat dissipation performance while meeting the need for miniaturization.

In order to achieve the above-described object, the heat dissipation structure for a substrate storage box according to the present invention is characterized by the following (1) to (5).
(1) a box in which a circuit board to be radiated is housed;
A board support portion for supporting the circuit board in the box;
An attachment portion to the vehicle body for attaching the box to the vehicle body formed in the box,
Have
A heat dissipation structure for a substrate storage box that releases heat of the circuit board to the vehicle body via a wall of the box and an attachment to the vehicle body,
The wall of the box that is most affected by external heat is made of a dissimilar metal laminate in which the outer layer is a low thermal conductive material and the inner layer is a high thermal conductive material.
(2) In the heat dissipation structure configured as described in (1) above,
The substrate support part supports the circuit board in a state in which heat conduction is possible in the box,
The heat of the circuit board transmitted through the board support part is released to the vehicle body through the wall of the box and the attachment part to the vehicle body.
(3) In the heat dissipation structure configured as described in (2) above,
The wall of the box body that is most affected by the external heat is constituted by a flat heat sink made of the dissimilar metal laminate, and an extension portion of the heat sink from the box body is used as an attachment portion to the vehicle body. In the state where the surface of the mounting portion on the side of the high heat conductive material is an attachment contact surface with respect to the vehicle body, and is in surface contact with the high heat conductive material inside the heat sink constituting the wall of the box, The board support part made of a high thermal conductivity material manufactured separately is attached, and the circuit board is screwed and fixed to the board support part.
(4) In the heat dissipation structure having the structure according to any one of (1) to (3) above,
Forming a heat insulating layer of silicon gel between the outer low thermal conductive material and the inner high thermal conductive material constituting the dissimilar metal laminate.
(5) In the heat dissipation structure having the structure according to any one of (1) to (4) above,
The base substrate of the circuit board is made of a metal core substrate.

According to the heat dissipation structure having the above configuration (1), the wall of the box that is most affected by the external heat is formed of a dissimilar metal laminate having an outer layer as a low thermal conductivity material and an inner layer as a high thermal conductivity material. Therefore, the influence of heat from the outside can be suppressed by the outer low heat conductive material. Therefore, the temperature difference between the box or the board support part and the circuit board can be increased, the heat flow rate can be increased, and the heat dissipation effect can be enhanced. Further, only a part of the wall of the box is made of a dissimilar metal laminate, and no special heat dissipating fins are provided, so that the need for miniaturization can be easily met.
According to the heat dissipation structure having the above configuration (2), the circuit board is supported in the box body in a state where heat can be conducted by the board support section, and the heat of the circuit board transmitted through the board support section is transferred to the wall of the box body. Since it escapes to the vehicle body via the attachment portion to the vehicle body, the heat dissipation effect by heat conduction can be enhanced.
According to the heat dissipation structure having the above configuration (3), the wall of the box body that is most affected by the external heat is formed by a flat heat sink made of a dissimilar metal laminate in which a low thermal conductivity material and a high thermal conductivity material are laminated. The extension of the radiator plate from the box is an attachment part to the vehicle body, the surface on the high heat conductive material side of the attachment part is an attachment contact surface to the vehicle body, and further, the inner side of the radiator plate constituting the wall of the box body Since the board support part made of the high thermal conductivity material made separately from the box is attached in a state where it is in surface contact with the high thermal conductivity material, and the circuit board is screwed and fixed to the board support part, the high thermal conductivity material The heat of the circuit board can be efficiently released to the vehicle body. Further, since the dissimilar metal laminate is used in the form of a flat plate, it can be manufactured at low cost without extra processing. Also, because the circuit board is fixed to the heat sink made of a dissimilar metal laminate among the walls of the box, the walls of other boxes can be made in a simple shape and manufactured by aluminum die casting In addition, unnecessary manufacturing costs can be reduced.
According to the heat dissipation structure having the configuration of (4) above, since the heat insulating layer of silicon gel is formed between the outer low thermal conductive material and the inner high thermal conductive material constituting the dissimilar metal laminate material, the box body is further improved. The influence of external heat on can be suppressed.
According to the heat dissipation structure having the configuration of (5) above, since the base substrate of the circuit board is a metal core substrate, by fixing the circuit board to the substrate support portion so that heat conduction between the metal core and the substrate support portion can be achieved, A further heat dissipation effect can be expected.

  ADVANTAGE OF THE INVENTION According to this invention, the heat dissipation structure of the board | substrate storage box which aimed at the improvement of heat dissipation performance can be provided, responding to the need for size reduction.

  The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading through the best mode for carrying out the invention described below with reference to the accompanying drawings.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a longitudinal sectional view showing a heat dissipation structure of the substrate storage box of the first embodiment. In FIG. 1, reference numeral 1 is a circuit board to be radiated, reference numeral 2 is a board storage box, and the circuit board 1 is accommodated in a box 3 of the board storage box 2. The circuit board 1 is composed of a base board having a metal core board (in which an insulator layer is provided on the surface of the metal core to equalize heat by heat conduction), and relays, fuses, switch elements, etc. on the metal core board. Such electrical parts are mounted.

  The box 3 includes a concave box main body 4 and a flat heat sink 5 as a lid that closes the opening surface. The heat radiating plate 5 is used in a portion corresponding to the wall of the box 3 that is most affected by external (inside the engine room) thermal influence (for example, the influence of radiant heat from a heat source), and is a dissimilar metal laminate 6 called a clad material. It consists of The dissimilar metal laminate 6 is a single composite plate in which the outer layer of the box 3 is a low thermal conductive material 6A and the inner layer of the box 3 is a high thermal conductive material 6B. Aluminum or copper is particularly suitable as the high heat conductive material, and iron is suitable as the low heat conductive material.

  One end of the heat radiating plate 5 extends outward from the size range constituting the box 3, and the extended portion serves as a mounting portion 11 to the vehicle body for mounting the box 3 to the vehicle body. In the case of this configuration, the surface of the attachment portion 11 on the high heat conductive material 6B side is an attachment contact surface 11a that is in close contact with the vehicle body, and the vehicle body is inserted through a through hole 12 formed in the attachment portion 11 through a screw (not shown). The substrate storage box 2 can be attached to the vehicle body by tightening to the vehicle body.

  Further, inside the box 3, a heat conduction nut 7 is attached as a board support part that supports the circuit board 1 in a state in which heat conduction is possible in the box 3. This heat conduction nut 7 is made of a high heat conductive material (made of aluminum or copper) separately from the box 3, and is attached to the high heat conductive material 6 </ b> B inside the radiator plate 5 constituting the wall of the box 3. The screw 8 passed from the outer surface side of the heat radiating plate 5 is attached to the inner surface of the heat radiating plate 5 by screwing the screw 8 passed from the outer surface side of the heat radiating plate 5 into the screw hole 7a on one end side of the heat conducting nut 7 in the state of surface contact. The circuit board 1 is attached to the heat conduction nut 7 by screwing a screw 9 passed from the upper side of the circuit board 1 into a screw hole 7 b on the other end side of the heat conduction nut 7.

  In this attached state, the heat generated in the circuit board 1 is transmitted to the high heat conductive material 6B of the heat radiating plate 5 through the heat conduction nut 7, and escapes from there to the vehicle body through the attachment portion 11 to the vehicle body. . In this case, the wall of the box 3 that is most affected by the external heat is composed of the dissimilar metal laminate 6 in which the outer layer is the low heat conductive material 6A and the inner layer is the high heat conductive material 6B. The influence of heat from the outside (heat source in the engine room) can be suppressed by the low heat conductive material 6A. Therefore, the temperature difference between the box 3 and the heat conduction nut 7 that is the substrate support portion and the circuit board 1 can be increased, and the heat flow rate can be increased to enhance the heat dissipation effect by heat conduction.

  Also, because the circuit board is fixed to the heat sink made of a dissimilar metal laminate among the walls of the box, the walls of other boxes can be made in a simple shape and manufactured by aluminum die casting In addition, unnecessary manufacturing costs can be reduced.

  In addition, for example, when a heat shield is provided in front of the substrate storage box 2 to reduce the thermal effect in the engine room, a new cost for attaching the heat shield is required. Since the same effect can be achieved only by replacing the material (replacement from a single layer plate to a dissimilar metal laminate plate), an increase in cost can be suppressed slightly.

  Further, the wall of the box 3 that is most affected by the external heat is constituted by a flat heat sink 5 made of a dissimilar metal laminate 6 in which a low heat conductive material 6A and a high heat conductive material 6B are laminated. An extension part from the body 3 is an attachment part 11 to the vehicle body, a surface on the high heat conductive material 6B side of the attachment part 11 is an attachment contact surface 11a with respect to the vehicle body, and further, a heat sink 5 constituting the wall of the box 3 A heat conduction nut 7 made of a high heat conduction material manufactured separately from the box 3 is attached in a state of surface contact with the inner high heat conduction material 6B, and the circuit board 1 is fixed to the heat conduction nut 7 with screws. Therefore, the heat of the circuit board 1 can be efficiently released to the vehicle body through the high thermal conductive material.

  Further, since the dissimilar metal laminate 6 is used in the form of a flat plate, it can be manufactured at low cost without extra processing. Moreover, since the circuit board 1 is fixed to the heat sink 5 made of the dissimilar metal laminate 6 among the walls of the box 3, the walls of the other boxes 3 can have a simple shape, and the aluminum die Even in the case of manufacturing by casting, it is possible to reduce unnecessary manufacturing costs.

  Further, since the base substrate of the circuit board 1 is a metal core board, a further heat radiation effect can be expected by screwing the circuit board 1 so that heat conduction between the metal core and the heat conduction nut 7 can be achieved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 2 shows a heat radiating plate 15 used in the second embodiment. In the heat dissipation structure of the second embodiment, the heat dissipation plate 15 of FIG. 2 is used as the lid of the box. Other configurations are the same as those in the first embodiment. Therefore, regarding the heat dissipation structure of the second embodiment, illustration of the entire embodiment is omitted as shown in FIG.

  As the heat sink 15, a dissimilar metal laminate 16 in which a heat insulating layer 6C made of silicon gel is formed between a low heat conductive material 6A located outside the box and a high heat conductive material 6B located inside is used. ing.

  Thus, when the dissimilar metal laminated material 16 in which the heat insulating layer 6C of silicon gel is formed between the outer low heat conductive material 6A and the inner high heat conductive material 6B is used as the heat radiating plate 15, there is the heat insulating layer 6C. Further, the external thermal influence on the box 3 can be suppressed.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  For example, a member having good heat conductivity other than the heat conduction nut 7 may be interposed between the circuit board 1 and the heat sinks 5 and 15.

  More specifically, in the heat dissipation structure of the board storage box 2, the board support portion (that is, the heat conduction nut 7 and / or other members having good heat conductivity) is interposed between the circuit board 1 and the heat sinks 5 and 15. In addition, the circuit board 1 is supported in the box 3 in a state where heat conduction is possible. However, even if the board support portion is made of a member that does not conduct heat or is difficult to conduct heat, the heat dissipation structure of the board storage box 2 converts the radiant heat from the circuit board 1 to the wall of the box 3 and the mounting portion to the vehicle body. Needless to say, it is possible to escape to the vehicle body via 11.

  In addition, as a material constituting the heat insulating layer 6C in FIG. 2, a resin other than silicon gel, rubber, or the like may be used.

It is a longitudinal cross-sectional view which shows the thermal radiation structure of the board | substrate storage box of 1st Embodiment of this invention. It is sectional drawing which shows the heat sink used by 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the heat dissipation structure of the conventional board | substrate storage box.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circuit board 2 Board | substrate storage box 3 Box body 5,15 Heat sink 6,16 Dissimilar metal laminated board 6A Low heat conductive material 6B High heat conductive material 6C Thermal insulation layer of silicon gel 7 Thermal conductive nut (board support part)
8, 9 Screw 11 Mounting part 11 to the vehicle body contact surface

Claims (5)

A box in which a circuit board to be dissipated is housed;
A board support portion for supporting the circuit board in the box;
An attachment portion to the vehicle body for attaching the box to the vehicle body formed in the box,
Have
A heat dissipation structure for a substrate storage box that releases heat of the circuit board to the vehicle body via a wall of the box and an attachment to the vehicle body,
A heat dissipation structure for a substrate storage box, characterized in that the wall of the box body that is most affected by external heat is made of a dissimilar metal laminate having an outer layer as a low thermal conductivity material and an inner layer as a high thermal conductivity material. The substrate support part supports the circuit board in a state in which heat conduction is possible in the box,
The heat dissipation of the circuit board storage box according to claim 1, wherein heat of the circuit board transmitted through the circuit board support part is released to the vehicle body through a wall of the box body and an attachment part to the vehicle body. Construction.   The wall of the box body that is most affected by the external heat is constituted by a flat heat sink made of the dissimilar metal laminate, and an extension portion of the heat sink from the box body is used as an attachment portion to the vehicle body. In the state where the surface of the mounting portion on the side of the high heat conductive material is an attachment contact surface with respect to the vehicle body, and is in surface contact with the high heat conductive material inside the heat sink constituting the wall of the box, 3. The heat dissipation structure for a substrate storage box according to claim 2, wherein the substrate support portion made of a high thermal conductivity material is attached separately, and the circuit board is screwed and fixed to the substrate support portion. .   4. The substrate according to claim 1, wherein a heat insulating layer of silicon gel is formed between an outer low thermal conductive material and an inner high thermal conductive material constituting the dissimilar metal laminate. 5. Storage box heat dissipation structure.   The base board of the said circuit board consists of a metal core board | substrate, The heat dissipation structure of the board | substrate storage box as described in any one of Claims 1-4 characterized by the above-mentioned.

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