JP2014236139A - Electronic control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in that the numbers of circuits and components dealing with high voltage and large current as of a motor drive circuit or transformation circuit have been increasing, the number of electronic components that generate heat by themselves has also been increasing, and, in a case where a space between a housing and an electronic component and a space between printed boards are sealed by filling the entire spaces with resin having heat conductivity higher than air, heat generated by the electronic component itself can be discharged out via the housing, which, however, adds the weight of injected resin, resulting in the heavier electronic control apparatus.SOLUTION: An electronic control apparatus comprises: a printed board on which electronic components are mounted; a housing accommodating this printed board; a through-hole formed in a side wall in this housing so as to face the electronic component; and discharging resin of high heat conductivity and low fluidity, injected from this through-hole to cover the electronic component and to block the opening of the through-hole. The discharging resin in the opening is exposed to the outside of the housing as well as blocking the opening.

Description

  The present invention relates to a heat dissipation structure for an electronic control device for an internal combustion engine in which a printed circuit board on which electronic components are mounted is housed in a housing.

In conventional electronic control equipment such as automobiles, a printed circuit board with connectors for connecting electronic components such as resistors, capacitors, transistors, and ICs to external devices is stored in a housing made of resin or metal. In addition, a structure for sealing the inside of the housing is provided for waterproofing electronic components.
For example, in the electronic control device disclosed in Patent Document 1, a printed circuit board on which a connector for connecting an electronic component such as a resistor, a capacitor, a transistor, and an IC and an external device is mounted in a resin casing, By applying a resin to the part and the connector of the board, the printed board, the electronic component, and the air inside are sealed to prevent moisture from entering. Due to the heat generated by the electronic components when such an electronic control device is used, the temperature of the air inside the housing rises, and the use environment temperature of the heat generating electronic components or other components increases. Higher operating temperature environment will lead to deterioration of characteristics and life, and in the worst case, it may lead to destruction of electronic parts. We are trying to ensure destruction and longevity.

  Moreover, although it is another field like patent document 2, it is equipped with the heat radiator with which a part is exposed outside the housing | casing for the same purpose, and the heat | fever which heat | fever-generates with an electronic component is thermally radiated by the heat radiator outside A technique is disclosed (paragraph 0016).

JP 2009-116764 A JP 2011-119564 A

  When the space between the casing, the electronic component, and the printed board is air as in the conventional electronic control device, the air in the casing is heated by the self-heating of the electronic component. In general, air, which is considered to have poor heat conduction, hardly conducts heat to the casing, and therefore the temperature inside the casing raises the ambient temperature of the component due to heat generation of the electronic component. When electronic parts are used, there are many cases where normal characteristics cannot be output if the ambient temperature is high, and if the temperature exceeds the operating temperature range specified by the manufacturer, the usable life is shortened, leading to destruction. In this way, the rise in ambient temperature must be reduced, but in recent years, circuits and parts that handle high voltage and large current, such as motor drive circuits and transformer circuits, have increased, and self-heating of electronic parts has also increased. Yes.

In addition, when the space between the housing, electronic components, and printed circuit board is filled and sealed with a resin that has better thermal conductivity than air, the self-heating of the electronic components can be radiated to the outside through the resin and the housing. However, since the weight of the filled resin is added, the electronic control device becomes heavy.
In order to suppress an increase in the ambient temperature of the electronic component, the present invention includes a structure for radiating the self-heating of the electronic component to the outside of the housing, and minimizes an increase in weight.

  An electronic control device according to the present invention includes a printed circuit board on which an electronic component is mounted, a housing for housing the printed circuit board, a through hole provided on the side wall of the housing so as to face the electronic component, and the through hole. And the heat-dissipating resin having high thermal conductivity and low fluidity that covers the electronic part and covers the opening of the through-hole, and the heat-dissipating resin of the opening closes the opening. Exposed outside the casing.

  According to the electronic control device of the present invention, since the heat generated by the electronic components mounted on the printed circuit board can be released to the outside of the housing through the resin in the space inside the sealed housing, the temperature inside the housing is increased. It is possible to suppress the deterioration of the characteristics of the electronic component and the destruction of the electronic component.

The housing | casing of the electronic control apparatus in Embodiment 1 of this invention is shown, (a) is a top view, (b) is sectional drawing of the II line | wire in Fig. (A). It is a disassembled perspective view which shows the internal structure of the electronic control apparatus in Embodiment 1 of this invention. It is the disassembled perspective view which looked at the internal structure of the electronic control apparatus of FIG. 2 from the connector side for a connection with an external device. (A) is a perspective view which shows the state after the assembly of FIG. 2, (b) is a perspective view which shows the state after the assembly of FIG. It is sectional drawing of the II-II line in FIG. It is sectional drawing which shows only the housing | casing of the electronic control apparatus in Embodiment 2 of this invention. It is sectional drawing which shows the internal structure of the housing | casing of the electronic control apparatus in Embodiment 3 of this invention. It is sectional drawing of the electronic control apparatus which shows the modification of Embodiment 3 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, the same code | symbol shows the same or an equivalent part between each figure.

Embodiment 1 FIG.
The electronic control apparatus according to the first embodiment will be described with reference to FIGS.
The electronic control device for an internal combustion engine according to the first embodiment includes a printed circuit board 3 on which a connector 4 for connecting to an external device and an electronic component 5 that generates heat at a high temperature are mounted, and a housing 1 that houses the printed circuit board 3. And a through hole 2 provided on the side wall of the housing 1 so as to face the electronic component 5, a high thermal conductivity covering the electronic component 5 injected from the through hole 2 and closing the opening of the through hole 2, and The heat-dissipating resin 6 closes the opening of the through hole 2 and the exposed surface exposed to the outside of the housing 1 generates heat generated in the electronic component 5. 1 radiates heat to the outside. The printed circuit board 3 is mounted with electronic components 5 that generate heat at a high temperature, such as a MOSFET, a transistor, an IC that controls a motor, and a capacitor that control switching of a large current.

The casing 1 has the casing opening 1A and the material is molded from resin. However, the same effect can be obtained by a casing molded from a metal material.
The printed circuit board 3 on which the connector 4 and the electronic component 5 are mounted is provided on the housing lid 11.
The through hole 2 is provided at a position on the upper surface of the housing 1 that overlaps the electronic component 5 when the printed circuit board 3 is accommodated in the lid body 1. A connector 4 for connecting to an external device is connected to the printed board 3 with a lead wire.

Next, the manufacturing process will be described.
First, in the state of FIGS. 2 and 3, the printed board 3 is inserted into the housing 1 from the housing opening 1A, the housing lid 11 is brought into contact with the housing opening 1A, and the housing opening 1A is closed. Finish. At this time, resin is applied to close the fine holes so that water does not enter the case from the fine holes formed at the contact portion between the case lid 11 and the case opening 1A. In this embodiment, the resin is applied to prevent water from entering, but packing such as rubber can provide the same effect as means for preventing water.
Next, for example, a heat-dissipating resin 6 made of silicon, which has higher thermal conductivity than air, is placed in a separate container (not shown) with a nozzle, and the nozzle of this separate container is connected to the electronic component 5 and the through hole 2. Set directly above. After setting, the heat-dissipating resin 6 put in a separate container is sent out from the nozzle through the through hole 2 toward the electronic component 5 and is applied to the electronic component 5. Further, the application of the heat-dissipating resin 6 is continued, and the application is continued until the through hole 2 is closed and the portion is sealed, and the resin is thermally cured. Here, a thermosetting resin is selected and cured, but the same effect can be obtained with a resin material that is naturally cured or not cured.

With the configuration described above, the heat generated by the electronic component 5 is released to the outside of the housing through the heat radiation resin 6. Further, if the area of the through hole 2 to which the heat radiating resin 6 is applied is increased, the surface area of the heat radiating resin 6 exposed to the outside of the housing is increased, so that the heat generated by the electronic component 5 is radiated to the outside of the housing. Can be further enhanced.
In addition, it is possible to further enhance the heat dissipation effect by mixing a material having high thermal conductivity, for example, glass filler stone, with the heat dissipation resin 6.

  Further, when the heat radiation resin 6 is made of a material having low fluidity, such as a silicon adhesive, as shown in FIG. 5, the heat radiation resin 6 is applied only to the periphery and the upper part of the electronic component 5 and is cured. Therefore, the entire space inside the casing is not filled with the heat-dissipating resin 6 but is applied only to a part, so that the weight of the electronic control device for the internal combustion engine can be reduced.

Embodiment 2. FIG.
The electronic control apparatus according to the second embodiment will be described with reference to FIG.
The housing 1 of the second embodiment is provided with a resin injection guide 7 facing the electronic component 5 and surrounding the electronic component as shown in FIG. According to the second embodiment, the heat radiation resin 6 can be applied along the resin injection guide 7.
By providing the resin injection guide 7 in this way, diffusion until the heat radiation resin 6 is cured can be prevented, and even if a highly fluid resin is used, the diffusion of the heat radiation resin 6 is prevented. The range to be selected can be widened.

Embodiment 3 FIG.
An electronic control device according to the third embodiment will be described with reference to FIG.
The electronic control device according to the third embodiment includes a printed circuit board pattern (not shown) formed by printing a copper foil for the purpose of heat dissipation and / or a circuit pattern having conductivity and heat conductivity with respect to the electronic component 5. The electronic component 5 is radiated through 8.
The electronic control device shown in FIG. 7 has a circuit pattern 8 that is conductive and thermally conductive to the electronic component 5 on the back surface of the printed circuit board 3 on which the electronic component 5 is mounted, and the circuit pattern 8 and the electronic component 5. The auxiliary circuit pattern 12 to be connected is provided, and the heat radiation resin 6 is applied to the circuit pattern 8 from the through hole 2 on the case side wall facing the circuit pattern 8 in the same manner as in the first embodiment. The circuit pattern 8 is a pattern formed by printing a copper foil for the purpose of connection and heat dissipation of the electronic component 5 and the electronic component, and the pattern of the printed board (not shown) is simply a copper foil printed for heat dissipation. It is a pattern.

Further, here, a case where the heat radiation resin 6 is applied from the through hole 2 to the circuit pattern 8 provided on the back surface opposite to the surface on which the electronic component 5 is mounted is described. When a circuit pattern or a printed circuit board pattern (not shown) is provided on the surface of the printed circuit board 3, a separate through hole (not shown) is provided on the case side wall facing the circuit pattern or the printed circuit board pattern. Will be provided.
In this case, the same effect can be obtained by applying the heat radiation resin 6 to the circuit pattern provided on the surface of the printed board 3 (with the electronic component 5 mounted) or the pattern of the printed board from the through hole.

  FIG. 8 shows a modified example of the third embodiment. In the same manner as in the first embodiment, the heat radiation resin 6 is applied to both the electronic component 5 and the circuit pattern 8. Other structures are the same as those in FIG.

  It should be noted that the present invention can be combined with each other within the scope of the invention, and each embodiment can be modified or omitted as appropriate.

  1: casing, 1A: casing opening, 11: casing lid, 2: through hole, 3: printed circuit board, 4: connector, 5: connector for connection, 6: resin for heat dissipation, 7: for resin injection Guide, 8: circuit pattern.

Electronic control devices according to the present invention, a printed circuit board mounted with electronic components on the surface, a circuit pattern having conductivity and heat conductivity to the electronic component is provided on the rear surface of the printed circuit board, the circuit pattern and the electronic component A housing containing the printed circuit board and the auxiliary circuit pattern for connecting the electronic circuit board , through holes provided on the side wall of the housing so as to face the electronic component and the circuit pattern, respectively , and injected from these through holes A heat-dissipating resin that covers both the electronic component and the circuit pattern and closes both openings of the through hole and has high thermal conductivity and low fluidity, and the heat-dissipating resin of the opening includes both openings. in which they exposed each to the outside of the casing with closing.

Claims (4)

  A printed circuit board on which an electronic component is mounted, a housing for housing the printed circuit board, a through hole provided on the side wall of the housing so as to face the electronic component, and injected from the through hole to cover the electronic component The heat-dissipating resin with high thermal conductivity and low fluidity that closes the opening of the through hole, and the heat-dissipating resin of the opening closes the opening and is exposed to the outside of the housing. Electronic control equipment characterized by that.   A printed circuit board on which an electronic component is mounted, a housing that houses the printed circuit board, a pattern that is provided on the front surface or the back surface of the printed circuit board and has conductivity and heat conductivity with respect to the electronic component, The through hole provided in the side wall of the housing and the heat-dissipating resin having a high thermal conductivity and low fluidity that covers the pattern and is injected from the through-hole and closes the opening of the through-hole, and The heat radiation resin of the opening blocks the opening and is exposed to the outside of the housing, and the heat of the electronic component is radiated to the outside of the housing through the pattern and the heat radiation resin. Electronic control equipment.   2. The electronic control device according to claim 1, wherein a pattern provided on the front surface or the back surface of the printed circuit board, a through hole provided on a side wall of the housing opposite to the pattern, and the pattern injected from the through hole And heat dissipation resin that has high thermal conductivity and low fluidity to cover the opening of the through hole, and dissipates heat generated by the electronic component to the outside of the housing through the pattern and the heat dissipation resin. Electronic control equipment characterized by   The electronic device according to any one of claims 1 to 3, wherein a guide for injecting the heat-dissipating resin is provided on a side wall of the housing so as to surround the electronic component or the pattern. Control equipment.