JP2007216823A - Case storage structure of on-vehicle control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure a low price and high reliability by optimizing a heat transfer structure, and to reduce a size by realizing the same heat transferring performance with a smaller occupation area. <P>SOLUTION: A heat transferring projecting member 31 is structured by a material having high temperature conductivity which is different from a material of a case main body 11 formed of a heat radiating fin 18, and also structured to divide into heat transferring and easing an influence to built-in components to external force received by the environment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a case housing structure for an in-vehicle control device mounted on a vehicle such as an automobile, and more particularly to a case housing structure for an in-vehicle control device in which a circuit board on which electronic components are mounted is housed in a case.

  An on-vehicle control device such as an electronically controlled internal combustion engine control device has a case housing structure in which a circuit board on which electronic components are mounted is housed in a sealed case. In such an in-vehicle control device, the circuit board is housed in a case having fins with a heat transfer structure connected by an elastic member such as a vibration-proof rubber having improved heat transfer properties.

Due to recent needs for miniaturization, electronic components that generate heat are concentrated, and the component mounting density of the circuit board is increased, so that functions related to heat transfer tend to be emphasized. In a vehicle-mounted control device in which a circuit board is housed in a case, the heat transfer structure from one side causes insufficient heat transfer due to the integration of heat generating electronic components. There is one that supports this by taking a heat transfer structure (for example, Patent Document 1).
Japanese Patent Laid-Open No. 2005-5671

  In addition to the function of fixing the circuit board, the case with fins for storing the circuit board has a function of fixing the in-vehicle control device to the body of the automobile. There is a problem that specialized materials cannot be selected. In consideration of productivity, it has been considered to be an inexpensive in-vehicle control device. Therefore, the material of the case with fins is in a state where it is necessary to select a material that is compromised to some extent with respect to heat transfer.

  In addition, the in-vehicle control device has an elastic member with improved heat transfer, in addition to the function of transferring heat, protects the circuit board from vibrations caused by vehicle running, etc., and absorbs dimensional variations between the circuit board and the case. In addition, mechanical functions such as thermal deformation absorption are necessary to prevent interference problems due to shrinkage and expansion due to temperature changes that occur during use, operation, and stopping. The heat transfer function and the mechanical function of the elastic member are contradictory in terms of dimensions and specifications. If importance is attached to heat transfer, the elastic member needs to be hard and thin, and the mechanical function is If it is important, it must be thick and soft.

  Further, if the heat transfer structure is provided on both sides of the electronic component mounted on the circuit board, the case housing structure of the circuit board becomes complicated, and the vehicle-mounted control device having an expensive heat transfer structure is obtained.

  The present invention has been made in view of the above problems, and the object of the present invention is to provide each of these functions as an optimum structure for each function such as a heat transfer function, a fixing function, and a mechanical function. An object of the present invention is to provide a case housing structure for an in-vehicle control device that is highly compatible, compact, lightweight, inexpensive, and highly reliable.

  In order to achieve the above object, a case housing structure for an in-vehicle control device according to the present invention is a case housing structure for an in-vehicle control device in which a circuit board on which electronic components are mounted is housed in a case, and is a separate part from the case. A heat transfer projection member is formed, a substrate-side elastic sheet member is formed on the top surface formed by one end surface of the heat transfer projection member, and a case is formed on the lower bottom surface formed by the other end surface of the heat transfer projection member. Side elastic sheet members are joined and installed, the board side elastic sheet member is joined and contacted to the back surface of the circuit board, the case side elastic sheet member is joined and contacted to the inner surface of the case, and the heat transfer protrusions are The case is made of a material having higher thermal conductivity than the material constituting the case.

  The case housing structure of the vehicle-mounted control device according to the present invention is preferably configured such that the case-side elastic sheet member is more easily elastically deformed than the substrate-side elastic sheet member, and the heat transfer protrusion member of the case-side elastic sheet member Each contact area between the lower bottom surface and the inner surface of the case is larger than each contact area between the top surface of the heat transfer protrusion member of the board-side elastic sheet member and the back surface of the circuit board.

  In the case housing structure of the in-vehicle control device according to the present invention, preferably, the case side elastic sheet member is made of a material having a higher thermal conductivity than the substrate side elastic sheet member.

  In the case housing structure of the vehicle-mounted control device according to the present invention, preferably, the case is integrally formed with heat radiation fins on the outer surface side of the case wall portion that forms the inner surface to which the substrate-side elastic sheet member is joined.

  According to the case housing structure according to the present invention, the elements responsible for each function such as the heat transfer function, the fixing function, and the mechanical function are separated and can be set to an optimum structure for each function, and the integrated electronic component Because it can transfer heat with an optimal structure, there are no centralized component mounting issues, ensuring high vibration absorption performance, absorbing dimensional variations without imposing a burden on the circuit board, and absorbing deformation due to heat, etc. Since it can do, the vehicle-mounted control apparatus which has high reliability can be comprised.

An embodiment of a case housing structure of an in-vehicle control device according to the present invention will be described with reference to the drawings.
Fig.1 (a) has shown schematic structure of the case accommodation structure of the vehicle-mounted control apparatus by this invention. In FIG. 1A, 10 indicates a case, 20 indicates a printed circuit board on which electronic components are mounted, and 30 indicates a heat transfer structure.

  As shown in FIG. 1B, the heat transfer structure 30 includes a heat transfer projection member 31 configured as a separate component from the case 10 and one end surface of the heat transfer projection member 31. The substrate-side elastic sheet member 32 bonded and installed on the top surface 31A and a case-side elastic sheet member 33 bonded and installed on the lower bottom surface 31B formed by the other end surface of the heat transfer projection member 31 are configured. .

  FIG. 2 shows details of an embodiment of the case housing structure of the in-vehicle control device according to the present invention. In FIG. 2, parts corresponding to those in FIG. 1 are described with the same reference numerals as those in FIG.

  In the printed circuit board 20, an electronic component 22 such as a CPU chip is mounted on a printed wiring board 21 on which a conductor pattern (not shown) is formed, and lead wires 24 are connected to an electrical connector 23 for electrical connection with the outside. Are electrically connected.

  The printed circuit board 20 is fixed to a board mounting seat 15 formed on the case 10 with screws 16 or the like.

  The case 10 includes an upper open box type case main body 11 and a cover member 13 screwed to the case main body 11 with screws 12 so as to close the upper open portion of the case main body 11, and defines a case inner space 14. is doing.

  The case body 11 is made of die-cast aluminum alloy or the like, and has a board mounting seat 15 integrally formed, and a printed circuit board 20 is fixed to the board mounting seat 15 with screws 16. Accordingly, the printed circuit board 20 is disposed and accommodated in the case internal space 14.

  A plurality of radiating fins 18 are integrally formed on the outer surface 17 </ b> A side of the bottom wall (case wall portion) 17 of the case body 11.

  Usually, a seal member 19 for ensuring waterproofness is disposed between the case main body 11 and the cover member 13 depending on the mounting environment and the like.

  The heat transfer projection member 31 is made of a material having a higher thermal conductivity than that of the case body 11 such as a copper alloy. That is, the heat transfer projection member 31 is made of a material different from that of the case body 11. The heat transfer projection member 31 has a truncated quadrangular pyramid shape, and the area of the lower bottom surface 31B is larger than the area of the top surface 31A.

  The board-side elastic sheet member 32 is made of a rubber-like elastic material with improved heat transfer properties, such as silicone rubber, and is bonded and bonded (bonded) to the entire top surface 31A of the heat transfer protrusion member 31 so that the entire surface is printed. The circuit board 20 is joined and contacted to the back surface (surface opposite to the mounting surface of the electronic component 22) 20A, in particular, to the corresponding portion of the arrangement position of the electronic component 22. The board-side elastic sheet member 32 is configured to be relatively hard and thin and have relatively good heat conductivity. That is, the board-side elastic sheet member 32 is set to have a thermal conductivity higher than that of the case-side elastic sheet member 33.

  The case-side elastic sheet member 33 is made of a rubber-like elastic material with improved heat transfer properties, such as silicone rubber, and is jointly installed (bonded) to the entire bottom surface 31B of the heat transfer projection member 31. It is in contact with the inner surface 17B formed by the bottom wall 17 of the main body 11. The case-side elastic sheet member 33 is softer and thicker than the substrate-side elastic sheet member 32 and is configured to be more easily elastically deformed than the substrate-side elastic sheet member 32.

  With the above-described structure, the contact area between the lower bottom surface 31B of the heat transfer protrusion member 31 of the case side elastic sheet member 33 and the inner surface 17B of the case body 11 is such that the heat transfer protrusion member 31 of the board side elastic sheet member 32 is. The contact area of each of the top surface 31A and the back surface 20A of the printed circuit board 20 is larger.

  In addition, the radiating fins 18 are integrally formed on the outer surface 17A side of the bottom wall 17 that is a case wall portion that forms the inner surface 17B to which the substrate-side elastic sheet member 32 is joined.

  According to the above configuration, the heat of the electronic component 22 of the printed circuit board 20 is transmitted exclusively through the board-side elastic sheet member 32, the heat transfer protrusion member 31, and the case-side elastic sheet member 33 to the case body 11, The heat is efficiently radiated from the outer surface of the case body 11 including the heat radiation fins 18 to the outside of the case.

  Since the heat transfer projection member 31 and the case main body 11 are separate members and are made of different materials, it is possible to adopt a structure specialized for each of heat transfer properties and mechanical properties. That is, the heat transfer projection member 31 and the case main body 11 can be configured as an optimum structure for each function of a mechanical function including a heat transfer function and a fixing function, respectively.

  In other words, the case main body 11 having the heat radiation fins 18 for optimizing the heat transfer function and the heat transfer projection member 31 provided for connecting the case main body 11 and the printed circuit board 20 are made of different materials. By forming with a thing, after ensuring a required mechanical function, heat transfer property can be improved.

  Since the case-side elastic sheet member 33 is configured to be elastically deformed more easily than the board-side elastic sheet member 32, the case-side elastic sheet member 33 exhibits high anti-vibration performance (the damping performance of vibration transmitted from the case main body 11 to the printed circuit board 20 is good). In addition, dimensional variation and thermal deformation can be absorbed well, and good mechanical characteristics can be secured.

  As a result, the case-side elastic sheet member 33 has a lower thermal conductivity than the substrate-side elastic sheet member 32, but the lower bottom surface 31 </ b> B of the case-side elastic sheet member 33 and the case main body 11. Each of the contact areas with the inner surface 17B of the substrate is larger than the contact areas of the top surface 31A of the heat transfer projection member 31 and the back surface 20A of the printed circuit board 20 of the substrate side elastic sheet member 32. Thermal conductivity equivalent to that of the sheet member 32 is ensured.

  In other words, in order not to deteriorate the heat transfer characteristics, the board side of the elastic material with improved heat transfer provided on the printed circuit board 20 side and used between the heat transfer projection member 31 and the printed circuit board 20 The elastic sheet member 32 is thin and uses a hard elastic material by further improving the heat conductivity.

  On the other hand, the case-side elastic sheet member 33 made of an elastic material with improved heat transfer, which is provided on the case body 11 side and used between the heat transfer projection member 31 and the case body 11, is thick and vibrated. An elastic material that is soft and slightly inferior to the extent that it can secure attenuation and a certain degree of dimensional variation and the ability to absorb thermal deformation is used.

  Thus, in order to eliminate the phenomenon in which the heat transfer performance between the heat transfer protrusion member 31 and the case body 11 is reduced, the heat transfer protrusion member 31 has a contact area larger than the contact area on the printed circuit board 20 side. The contact area on the case body 11 side of the thermal projection member 31 is increased, and the reduced heat transfer performance is compensated for by the contact area.

  Since the contact area on the printed circuit board 20 side may be small, it is possible to minimize the effective mounting area of the printed circuit board 20 by the heat transfer projection member 31.

  The structure in which the contact area on the case body 11 side of the heat transfer projection member 31 is larger than the contact area on the printed circuit board 20 side of the heat transfer projection member 31 is that the heat transfer projection member 31 has a truncated cone shape. 3, as shown in FIG. 3, a recess 41 is formed at the end of the heat transfer projection member 31 on the case body 11 side, and a case-side elastic sheet member 33 is sandwiched between the case body 11. The convex part 42 which the recessed part 41 fits can be formed, and the contact area can be expanded so that the case side elastic sheet member 33 exists also in the peripheral part of the fitting part of the recessed part 41 and the convex part 42. In this structure, an air escape groove 43 is provided.

  In this embodiment, compared to the embodiment shown in FIG. 2, the contact area of the heat transfer projection member 31 with the case body 11 is equal to that of the embodiment shown in FIG. 2. The outer shape of the heat transfer projection member 31 can be reduced while ensuring.

  As shown in FIG. 4, a recess 44 is formed in the case body 11, and the end of the heat transfer projection member 31 is fitted into the recess 44 with the case-side elastic sheet member 33 interposed therebetween. But you can. Also in this case, it is possible to increase the contact area so that the case-side elastic sheet member 33 exists also in the peripheral portion of the fitting portion between the concave portion 44 and the end portion of the heat transfer projection member 31.

  Therefore, also in this embodiment, the contact area of the heat transfer projection member 31 with the case main body 11 is equal to that of the embodiment shown in FIG. 2 than in the embodiment shown in FIG. The outer shape of the heat transfer protrusion member 31 can be reduced while securing the area, and the shape of the heat transfer protrusion member 31 can be simplified.

  As explained above, heat transfer can be achieved with a structure equivalent to the current technology (single-sided heat transfer structure), so it is cheaper to apply in more severe environments and adopt parts with lower temperature guarantee. A highly reliable control device for an internal combustion engine can be constructed. Further, the heat transfer performance equivalent to that of the prior art can be achieved with a small contact area with the substrate, and a mounting area can be secured, so that downsizing can also be achieved. In addition, because it specializes in heat dissipation characteristics, it is possible to increase the mounting area of electronic components by consolidating heat generating components and reducing the contact area of the heat transfer projection member with the printed circuit board, thereby achieving miniaturization. be able to. In addition, high reliability can be ensured because dimensional variations and thermal deformation can be absorbed into the substrate with minimal influence.

  As a result, as an optimal structure for each function such as heat transfer function, fixed function, mechanical function, etc., these functions are highly compatible with each other, and the case of a compact, lightweight, inexpensive and highly reliable on-board controller. A housing structure is obtained.

(A) is a perspective view which shows schematic structure of the case accommodation structure of the vehicle-mounted control apparatus by this invention, (b) is an expansion disassembled perspective view of the principal part. The longitudinal cross-sectional view which shows in detail one Embodiment of the case accommodation structure of the vehicle-mounted control apparatus by this invention. The longitudinal cross-sectional view of the principal part which shows in detail the other embodiment of the case accommodation structure of the vehicle-mounted control apparatus by this invention. The longitudinal cross-sectional view of the principal part which shows in detail the other embodiment of the case accommodation structure of the vehicle-mounted control apparatus by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Case 11 Case main body 12 Screw 13 Cover member 14 Case inner space 15 Board | substrate attachment seat part 16 Screw 17 Bottom wall (case wall part)
18 Heat radiation fin 19 Seal member 20 Printed circuit board 21 Printed wiring board 22 Electronic component 23 Electrical connector 24 Lead wire 30 Heat transfer structure 31 Heat transfer projection member 32 Board side elastic sheet member 33 Case side elastic sheet member 41 Recess 42 Projection Portion 43 Air escape groove 44 Recess

Claims (4)

A case housing structure for an in-vehicle control device in which a circuit board on which electronic components are mounted is housed in a case,
A heat transfer projection member is formed as a separate component from the case, the substrate-side elastic sheet member is formed on the top surface formed by one end surface of the heat transfer projection member, and the other end surface of the heat transfer projection member is formed. Case-side elastic sheet members are joined and installed on the lower bottom surface, the board-side elastic sheet member is in contact with the back surface of the circuit board, the case-side elastic sheet member is in contact with the inner surface of the case, and A case housing structure for an in-vehicle control device, wherein the heat transfer protrusion is made of a material having a higher thermal conductivity than the material constituting the case.   The case-side elastic sheet member is configured to be more easily elastically deformed than the substrate-side elastic sheet member, and each contact between the lower bottom surface of the heat transfer protrusion member of the case-side elastic sheet member and the inner surface of the case. 2. The in-vehicle control device according to claim 1, wherein an area is larger than each contact area between the top surface of the heat transfer protrusion member of the board-side elastic sheet member and the back surface of the circuit board. Case housing structure.   The case housing structure for an in-vehicle control device according to claim 1 or 2, wherein the case side elastic sheet member is made of a material having a higher thermal conductivity than the substrate side elastic sheet member.   The heat radiation fin is integrally formed in the said case at the outer surface side of the case wall part which forms the said inner surface where the said board | substrate side elastic sheet member joins, The Claim 1 characterized by the above-mentioned. Case housing structure of the on-vehicle control device described.

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