JP4122862B2 - Heat dissipation structure for electronic devices - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a heat dissipation structure for an electronic device on which an electronic component having heat generation is mounted.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an electronic device mounted on an automobile or the like is configured by mounting an electronic component on a printed board and housing the printed board on which the electronic component is mounted in a case (housing). And since this electronic component includes an electronic component that generates a considerable amount of heat, such as a power transistor, the electronic device transfers the heat generated from such an electronic component to the outside of the case. A heat dissipation structure that dissipates heat is applied. In the conventional heat dissipation structure, as shown in FIG. 5 , a heat dissipating member 6 such as a heat dissipating gel or a heat dissipating sheet is formed between the printed board 4 on which the heat generating element 8 is mounted and the ECU housing 2 to generate heat. Heat generated from the element 8 is released from the printed circuit board 4 to the ECU housing 2 via the heat dissipation member 6.
[0003]
[Problems to be solved by the invention]
By the way, in recent years, components mounted on automobiles and the like, particularly components mounted on the engine room of a vehicle, can further improve the heat dissipation performance of electronic components including heating elements in order to ensure high reliability of the device. It is desired. As a means for improving the heat dissipation performance, there is a means for reducing the thickness T of the heat dissipation member 6.
[0004]
However, if the thickness T of the heat dissipating member 6 is reduced, it is difficult to maintain the influence of warpage generated on the printed circuit board 4 and the processing accuracy of the ECU housing 2 , so that the printed circuit board 4 and the ECU housing 2 come into contact with each other and short. This causes a problem that the electronic device malfunctions.
[0005]
Therefore, the present invention has been made in view of the above problems, and an electronic device capable of improving heat dissipation performance by reducing the distance between the printed circuit board and the housing as much as possible without causing malfunction of the electronic device. It aims at providing the heat dissipation structure of an apparatus.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, which is achieved in order to achieve the above object, a casing made of a material having a heat dissipation function and a wiring pattern are formed, and an electronic component is mounted on the wiring pattern. And a resin circuit board attached to the casing so as to face the inner wall surface of the casing and having a gap between the inner wall surface, and a heat dissipation member provided between the casing and the circuit board A heat dissipating structure of an electronic device that releases heat generated by the electronic component to the outside through the heat dissipating member and the housing, and is located away from the mounting position of the circuit board to the housing Between the casing and the circuit board, contact preventing means for preventing contact between the casing and the circuit board is formed at a position different from the position of the wiring pattern formed on the circuit board.
[0007]
Then, the contact prevention means is mounted of a protrusion having a predetermined height is formed in the housing, the predetermined height of the protrusions, the top of the protrusion of the circuit board to the housing The height is lower than the mounting surface height at the position .
[0008]
Thus, according to the present invention, even if the distance between the circuit board and the housing is reduced, the first contact is the contact prevention means formed at a position different from the wiring pattern of the circuit board. While preventing a short circuit or the like due to contact with the housing, the distance between the circuit board and the housing can be shortened, and thus the thickness of the heat dissipation member can also be shortened.
[0009]
As a result, it is possible to reduce the distance between the circuit board and the housing as much as possible without causing malfunction of the electronic device, and to further improve the heat dissipation performance.
[0013]
Furthermore, the heat dissipating member provided between the housing and the circuit board may have an adhesive action as in the fourth aspect of the invention. According to this configuration, when the circuit board is attached to the casing, it is not necessary to fix the circuit board with screws or the like, and the circuit board and the casing can be easily attached.
[0014]
Further, the heat dissipation structure for an electronic device according to any one of claims 1 to 4 may be applied to an electronic device mounted on a vehicle as in the invention according to claim 5 . Since components mounted on a vehicle, particularly components mounted on an engine room or the like have severe usage conditions such as temperature, the heat dissipation effect of the present invention is improved and the heat dissipation effect becomes more suitable.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, a preferred embodiment of a heat dissipation structure for an electronic device according to the present invention will be described with reference to the drawings. In the present embodiment, a description will be given of a case where the heat dissipation structure of an electronic device is applied to an electronic device of an automobile.
[0016]
FIG. 1 is an overall configuration diagram showing an overview of an electronic apparatus according to the present embodiment. An electronic device (hereinafter referred to as an ECU) 10 includes a casing 2 and a metal lid 3 constituting the case 1, a printed circuit board 4 accommodated in the case 1, an external sensor (not shown), an external electronic device, and the like. Connector 5 for taking in various signals from, and a heat radiating member 6 provided between the housing 2 and the printed circuit board 4.
[0017]
The housing 2 is made of an aluminum material having a heat dissipation action, and has a protrusion 7 to be described later on the side to which the printed circuit board 4 is attached.
[0018]
The printed circuit board 4 is a resin substrate (in this embodiment, a glass cloth is used as a base material and a substrate is impregnated with an epoxy resin), and a wiring pattern (not shown) is formed on the substrate. Then, electronic components 8 such as a one-chip microcomputer, a power transistor, a resistor, and a capacitor are mounted along the wiring pattern to form a control circuit for driving an external actuator.
[0019]
The connector 5 has connector pins 9 and is electrically connected to the wiring pattern on the printed circuit board 4 via the connector pins 9. When various signals from an external sensor, an external electronic device, etc. are received via the connector 5, various arithmetic processes for driving an external actuator are executed by the plurality of electronic components 8 mounted on the printed circuit board 4. Is done.
[0020]
Next, details of the heat dissipation structure of the ECU 10 that releases heat generated in the electronic component 8 in the housing 2 will be described with reference to FIG.
[0021]
In order to form the heat dissipation structure of the electronic device 10 as shown in FIG. 2, the electronic component 8 is soldered onto the wiring pattern of the printed circuit board 4 with the solder 11, and the printed circuit board 4 on which the electronic component 8 is mounted. Is attached to the housing 4 via the heat dissipating member 6. At the time of attachment, as shown in FIG. 2, a heat radiating member 6 having an adhesive action is attached to the housing 2 in advance, and the periphery of the printed circuit board 4 is placed on the edge of the housing 2 while the heat radiating member 6 is attached. put down the printed board 4 above, attaching adhered allowed by the radiation member 6 to the printed circuit board 4 to the housing 2 so as to have a gap between the housing 2 and the printed circuit board 4.
[0022]
The housing 2 is formed with a protrusion 7 for preventing contact between the housing 2 and the printed circuit board 4. The protrusion 7 has a predetermined height T ′ so as to prevent contact between the housing 2 and the printed circuit board 4. This predetermined height is determined based on the size of unnecessary solder scraps protruding on the side where the electronic component 8 of the printed circuit board 4 is not mounted, the size of the flash of the housing 2, the warp of the substrate 4, and the like. . That is, unnecessary solder scraps and small flashes of the housing 2 are left without being removed, and the substrate 4 that is not greatly deformed is used as it is as an electronic device. Therefore, the predetermined height T ′ of the protrusion 7 is determined so as to be higher than the reference with the allowable size as a reference.
[0023]
Furthermore, the protrusion 7 is formed so as to be at a position different from the position of the wiring pattern formed on the printed board 4 when the printed board 4 is attached to the housing 2. The position different from the position of the wiring pattern refers to a portion where the wiring pattern is not formed on the substrate 4 and corresponds to, for example, a ground pattern.
[0024]
In addition, although this embodiment demonstrated what applied the heat dissipation structure of the electronic device to the electronic device of a motor vehicle, it is not limited to this, You may apply to another electronic device.
[0025]
As described above, in this embodiment, the protrusion 2 having the predetermined height T ′ is formed on the housing 2, and even if the interval T between the printed circuit board 4 and the housing 2 is reduced, the first contact is made. Is a protrusion 7 formed at a position different from the position of the wiring pattern formed on the printed circuit board 4, so that a short circuit or the like due to contact between the printed circuit board 4 and the housing 2 is prevented and the printed circuit board 4 The distance T from the housing 2, that is, the thickness of the heat radiating member 6 can be shortened to a predetermined height T ′ of the protrusion. Therefore, it is possible to further improve the heat dissipation performance without causing a malfunction of the electronic device 10. In particular, when the electronic component 8 is mounted in an engine room or the like, use conditions such as temperature are severe, so that the heat dissipation effect is improved and more preferable by using the heat dissipation structure of the present invention.
[0026]
Further, since the heat radiating member 6 has an adhesive action, the printed circuit board 4 can be attached to the housing 2 while being adhered. As a result, it is not necessary to fix with screws or the like at the time of attachment, and simple attachment becomes easy.
[0027]
( Reference example )
In the above embodiment, the description is made as to form a protrusion 7 having a predetermined height T 'in the housing 2, in the reference example of FIG. 3, to form a protrusion 17 on the printed circuit board 4. The protrusion 17 has a predetermined height T ′ as in the above embodiment, and is formed at a position different from the position of the wiring pattern on the printed circuit board 4 . In this configuration, it is easier to position the protrusion 17 at a position different from the position of the wiring pattern as compared with the case where the protrusion 7 is formed on the housing.
[0028]
Further, in the reference example shown in FIG. 4, it is mixed with the insulating member 70 having a predetermined size to the heat dissipation member 6. The insulating member 70 may be a spherical member whose diameter is a predetermined height T ′ of the protrusions 7 and 17 described above. Further, as long as the predetermined size T ′ can be secured, the shape may be any shape. According to this configuration, even shorten the interval T between the printed circuit board 4 and the housing 2, the insulating member 70 having a predetermined size T 'can prevent contact with the printed circuit board 4 and the housing 2 Become. Further, in this configuration, it is only necessary to mix the insulating member 70 into the heat radiating member 6.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an automotive electronic device to which a heat dissipation structure of an embodiment is applied.
FIG. 2 is a configuration diagram illustrating a heat dissipation structure of an electronic device having a protrusion on a housing.
FIG. 3 is a configuration diagram showing a heat dissipation structure of an electronic device having a protrusion on a printed circuit board.
FIG. 4 is a configuration diagram showing a heat dissipation structure of an electronic device in which an insulating member is mixed in the heat dissipation member.
FIG. 5 is a configuration diagram illustrating a heat dissipation structure of a conventional electronic device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Case 2 Case 4 Printed circuit board 6 Heat radiation member 7, 17 Protrusion part 8 Electronic component 10 Electronic device 70 Insulation member

Claims (5)

A housing made of a material having a heat dissipation action;
A wiring pattern is formed, an electronic component is mounted on the wiring pattern, and the resin is attached to the housing so as to face the inner wall surface of the housing and have a gap between the inner wall surface and a circuit board,
A heat dissipation member provided between the housing and the circuit board;
A heat dissipation structure of an electronic device configured to release heat generated by the electronic component to the outside through the heat dissipation member and the housing,
Contact prevention means for preventing contact between the casing and the circuit board is provided between the casing and the circuit board at a position away from the mounting position of the circuit board to the casing. Formed in the housing as a protrusion having a predetermined height at a position different from the position of the wiring pattern formed on the substrate ,
The predetermined height of the protruding portion is a height at which the top of the protruding portion is lower than the mounting surface height at the mounting position of the circuit board to the housing. Construction. 2. The heat dissipation structure for an electronic device according to claim 1, wherein the heat dissipation member is provided in a region between the housing and the circuit board corresponding to a mounting position of the electronic component that generates the heat. A heat dissipation structure for an electronic device. 3. The heat dissipation structure for an electronic device according to claim 2 , wherein the contact preventing means is disposed in the one region . 4. The heat dissipation structure for an electronic device according to claim 1 , wherein the heat dissipation member has an adhesive action . 5. The heat dissipation structure for an electronic device according to any one of claims 1 to 4, wherein the heat dissipation structure for an electronic device is applied to an electronic device mounted on a vehicle .

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