WO2021075360A1

WO2021075360A1 - Electronic control device

Info

Publication number: WO2021075360A1
Application number: PCT/JP2020/038235
Authority: WO
Inventors: 康博露木; 利昭石井; 河合　義夫
Original assignee: 日立Astemo株式会社
Priority date: 2019-10-17
Filing date: 2020-10-09
Publication date: 2021-04-22
Also published as: JP7372810B2; JP2021064771A

Abstract

In order to suppress thermal interference between adjacent electronic components while minimizing the increase in the wiring length between the electronic components, electronic components 11a, 11b are mounted adjacent to each other on a circuit board 12, the circuit board 12 is affixed to a base equipped with a rectangular protrusion 21, N (N being an integer of 2 or greater) through holes 12c are formed between the mounting region of the electronic component 11a and the mounting region of the electronic component 11b, and the terminals 17a, 17b of the electronic components 11a, 11b are connected via the shortest path by wiring 16a disposed between the through holes 12c.

Description

Electronic control device

The present invention relates to an electronic control device that can be mounted on a vehicle.

The amount of heat generated by electronic components is increasing due to the sophistication of in-vehicle electronic control devices. Further, in an automatic driving system or the like, due to the necessity of high-speed transmission between electronic parts, close arrangement between electronic parts is required. Generally, heat-generating electronic components are thermally connected to a heat-dissipating block provided in a housing or the like via a heat-dissipating member to dissipate heat. Further, from the viewpoint of reducing the weight of the in-vehicle electronic control device, the development of the in-vehicle electronic control device using a material such as a high thermal conductive resin for the housing is in progress. In an in-vehicle electronic control device using the above material for a housing, when a plurality of heat-generating electronic components are arranged close to each other, heat is generated between the plurality of heat-generating electronic components arranged in a heat-dissipating block that dissipates heat from the heat-generating electronic components. There is a temperature rise of each heat-generating electronic component due to interference. In order to suppress thermal interference between heat-generating electronic components, Patent Document 1 proposes a structure in which a single hole is formed in a substrate to suppress thermal interference.

Japanese Unexamined Patent Publication No. 2006-173243

From the viewpoint of weight reduction, in an in-vehicle electronic control device using a material such as a high thermal conductive resin for the housing, thermal interference occurs between heat-generating electronic components arranged in close proximity, and a metal housing is used. The temperature of electronic components rises compared to the case.

Therefore, it is required to suppress the temperature rise of the heat-generating component due to thermal interference on the substrate on which the electronic component is mounted. When the structure disclosed in Patent Document 1 is adopted in order to suppress such a temperature rise, since thermal interference is suppressed in the single hole portion, a wiring path between electronic components may become impossible. It becomes long and interferes with high-speed transmission of signals between heat-generating electronic components.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic control device capable of suppressing thermal interference between electronic components while suppressing an increase in wiring length between adjacent electronic components. There is.

In order to achieve the above object, the electronic control device according to the first aspect includes a circuit board in which the first electronic component and the second electronic component are mounted adjacent to each other, a housing for fixing the circuit board, and the like. A low thermal conductive portion provided on the circuit board and having a smaller thermal conductivity than the circuit board is provided, and the low thermal conductive portion is located between a mounting region of the first electronic component and a mounting region of the second electronic component. It is arranged discretely in the middle region of.

According to the present invention, it is possible to suppress thermal interference between electronic components while suppressing an increase in wiring length between adjacent electronic components.

FIG. 1 is a perspective view showing the configuration of the in-vehicle electronic control device according to the first embodiment in an exploded manner. FIG. 2 is an exploded perspective view showing the configuration of the in-vehicle electronic control device when the through hole 12c of FIG. 1 is not provided. FIG. 3 is a cross-sectional view showing a configuration in which the in-vehicle electronic control device of FIG. 1 is cut at the positions of the

electronic components

11a and 11b. FIG. 4 is a plan view showing the configuration of a circuit board on which the

electronic components

11a and 11b of FIG. 3 are mounted. FIG. 5 is a cross-sectional view showing the heat propagation direction in the thermal interference path between the

electronic components

11a and 11b of FIG. FIG. 6 is a plan view showing a heat dissipation path in the circuit board on which the

electronic components

11a and 11b of FIG. 3 are mounted. FIG. 7 is a plan view showing a configuration of a circuit board applied to the in-vehicle electronic control device according to the second embodiment. FIG. 8 is a plan view showing a configuration of a circuit board applied to the in-vehicle electronic control device according to the third embodiment. FIG. 9 is a cross-sectional view showing a peripheral configuration of

electronic components

11a and 11b applied to the in-vehicle electronic control device according to the fourth embodiment. FIG. 10 is a cross-sectional view showing a peripheral configuration of

electronic components

11a and 11b applied to the in-vehicle electronic control device according to the fifth embodiment. FIG. 11 is a cross-sectional view showing a peripheral configuration of

electronic components

11a and 11b applied to the in-vehicle electronic control device according to the sixth embodiment. FIG. 12 is a cross-sectional view showing a peripheral configuration of an electronic component 11 applied to the in-vehicle electronic control device according to the first comparative example. FIG. 13 is a cross-sectional view showing the peripheral configurations of the

electronic components

11a and 11b applied to the in-vehicle electronic control device according to the second comparative example. FIG. 14 is a plan view showing the configuration of a circuit board on which the

electronic components

11a and 11b of FIG. 13 are mounted. FIG. 15 is a cross-sectional view showing the heat propagation direction in the thermal interference path between the

electronic components

11a and 11b of FIG. FIG. 16 is a cross-sectional view showing the peripheral configurations of the

electronic components

11a and 11b applied to the in-vehicle electronic control device according to the third comparative example. FIG. 17 is a plan view showing the configuration of a circuit board on which the

electronic components

11a and 11b of FIG. 16 are mounted. FIG. 18 is a diagram comparing the temperatures of electronic components when a metal and a high thermal conductive resin are used as a housing material for fixing a circuit board on which an electronic component is mounted alone. FIG. 19 is a diagram comparing the temperatures of electronic components when a metal and a high thermal conductive resin are used as a housing material for fixing a circuit board on which electronic components are mounted adjacent to each other. FIG. 20 is a diagram showing a comparison between the first, second and third embodiments and the numerical examples of the temperature rise of the first, second and third comparative examples. 21 (a) to 21 (c) are plan views showing other examples of intermediate regions between mounting regions of electronic components.

The embodiment will be described with reference to the drawings. It should be noted that the embodiments described below do not limit the invention according to the claims, and all of the elements and combinations thereof described in the embodiments are indispensable for the means for solving the invention. Not necessarily.

In the following description, as the electronic control device, an in-vehicle electronic control device mounted on a vehicle will be taken as an example.
FIG. 1 is a perspective view showing the configuration of the in-vehicle electronic control device according to the first embodiment in an exploded manner.
In FIG. 1, the vehicle-mounted electronic control device 1 includes a circuit board 12 and a housing 10. The housing 10 includes a base 13 and a cover 14.

Electronic components 11a to 11c are mounted on the circuit board 12. The electronic components 11a to 11c are heat-generating electronic components such as semiconductor elements. The electronic components 11a to 11c can be mounted on the circuit board 12 in a package in which a semiconductor chip is sealed, for example. This package is, for example, SOP (Small Outline Package), QFP (Quad Flat Package) or BGA (Ball grid array).

Here, the

electronic components

11a and 11b are mounted on the circuit board 12 adjacent to each other.
The calorific value of the

electronic components

11a and 11b may be different from each other. The electronic component 11a is, for example, a microcomputer, and the electronic component 11b is, for example, an ASIC (Application Specific Integrated Circuit).

In addition to the electronic components 11a to 11c, passive components such as resistors and capacitors forming the electronic circuit are electrically connected to one or both sides of the circuit board 12 using a conductive connection material such as solder. Will be done.

Further, the connector 15 is mounted on the circuit board 12. The connector 15 electrically connects the circuit board 12 and the outside. The connector 15 can be arranged at the end of the circuit board 12. A required number of pin terminals 15a are inserted into the main body of the connector 15 by press fitting or the like. The connector 15 is electrically joined to the circuit board 12 by soldering or press-fitting the pin terminal 15a to the circuit board 12.

The circuit board 12 includes N (N is an integer of 2 or more) through holes 12c. The N through holes 12c are arranged in the intermediate region RM1 between the mounting region of the electronic component 11a and the mounting region of the electronic component 11b. At this time, the N through holes 12 can be arranged at positions that do not protrude from the intermediate region RM1. The planar shape of the through hole 12c is not necessarily limited to a round shape, and may be an elliptical shape, a rectangular shape, or a polygonal shape.

The N through holes 12c can be used as a low thermal conductivity portion having a smaller thermal conductivity than the circuit board 12. At this time, the low heat conductive portions are discretely arranged in the intermediate region RM1 between the mounting region of the electronic component 11a and the mounting region of the electronic component 11b. Here, the N through holes 12c can be arranged at positions where the temperature lowering effect due to the suppression of thermal interference between the

electronic components

11a and 11b exceeds the temperature rise effect due to the decrease in heat dissipation of the circuit board 12. At this time, N through holes 12c can be arranged so that the component temperatures of the

electronic components

11a and 11b are 150 ° C. or lower.

As a method for forming the through hole 12c, a method such as punching, drilling, laser processing or a chemical etching method may be used alone, or a combination of these methods may be used.
If the through hole 12c is formed in the circuit board 12, the method is not limited to the above.

Further, the circuit board 12 is provided with a screw hole 12d. A screw 22 as an example of a fastening member can be inserted into the screw hole 12d. The screw holes 12d can be arranged at the four corners of the circuit board 12.

As the circuit board 12, for example, a laminated wiring board made of a thermosetting resin, a glass cloth, and a metal wiring in which a circuit pattern is formed, a board made of ceramics and metal wiring, a flexible board such as polyimide, or the like can be used.

The housing 10 fixes the circuit board 12. At this time, the circuit board 12 is fixed to the base 13. The base 13 includes a frame member 13a that supports the circuit board 12 on the base 13. Pedestal portions 13b are provided at the four corners of the frame member 13a. The base 13 has a substantially rectangular flat plate shape as a whole so as to close the opening on the lower surface of the cover 14. The base 13 and the pedestal portion 13b are provided with screw holes 13d.

Further, a rectangular convex portion 21 is provided on the base 13. The rectangular convex portion 21 is arranged so as to come under the

electronic components

11a and 11b when the circuit board 12 is assembled to the housing 10. The rectangular convex portion 21 comes into contact with or close to the circuit board 12 when the circuit board 12 is assembled to the housing 10, and can improve the heat dissipation of the

electronic components

11a and 11b. At this time, the frame member 13a supports the circuit board 12 on the base 13 so that the circuit board 12 comes into contact with or is close to the rectangular convex portion 21.

The cover 14 protects the circuit board 12 from impact, dust, and the like. The cover 14 has a box shape or a lid shape with an open lower surface, which is assembled to the base 13 so as to cover the circuit board 12.

The base 13 and the cover 14 are assembled by sandwiching the circuit board 12 to which the connector 15 is attached to form a box-type in-vehicle electronic control device. For example, the circuit board 12 is fixed to the housing 10 by being sandwiched between the pedestal portion 13d and the cover 14 and screwed into the cover 14 with the screws 22 inserted into the screw holes 13d and 12d. To.

The structure for fixing the cover 14 and the base 13 in combination is not limited to the structure for screwing and fixing with the screws 22. For example, the assembly hole provided in the upright portion rising from the base 13 and the protrusion provided in the cover 14 may be fitted and fixed, or may be adhesively fixed.

The base 13 is manufactured by casting, pressing, cutting or injection molding using a resin composite material. The thermal conductivity of the resin composite material is preferably 30 W / m · K or less.

The cover 14 is manufactured by casting, pressing or cutting, injection molding, etc. using a metal material or a resin composite material. For example, as a metal material, a material obtained by casting or rolling an alloy containing aluminum, magnesium, iron or the like as a main component can be used, and as a resin composite material, a material composed of a resin and a filler can be used. it can.

This resin composite material is at least one selected from, for example, a thermoplastic resin such as polybutylene terephthalate, polyamide, polyethylene terephthalate or polyphenylene sulfide, or a thermosetting resin such as epoxy resin, phenol resin, polyimide resin or unsaturated polyester resin. A mixture of the above resin and an inorganic filler such as glass fiber, silica or alumina, or at least one kind of metal powder is molded by injection molding, compression molding, transfer molding or the like.

This resin composite material can be used as a high thermal conductive resin. Here, by using a resin composite material composed of a resin and a filler for the base 13 and the cover 14, the weight of the in-vehicle electronic control device 1 can be reduced.

Further, by providing N through holes 12c in the circuit board 12, it is possible to arrange the through holes 12c at intervals. Therefore, it is possible to secure a region for wiring between the

electronic components

11a and 11b on the circuit board 12 without bypassing the through hole 12c, and the circuit board 12 is transmitted horizontally between the

electronic components

11a and 11b. The heat can be blocked. As a result, it is possible to reduce the thermal interference between the

electronic components

11a and 11b, suppress the temperature rise of the

electronic components

11a and 11b, and suppress the increase in the wiring length of the wiring between the

electronic components

11a and 11b. This makes it possible to realize high-speed transmission of signals between the

electronic components

11a and 11b.

FIG. 2 is an exploded perspective view showing the configuration of the in-vehicle electronic control device when the through hole 12c of FIG. 1 is not provided.
In FIG. 2, the vehicle-mounted electronic control device 2 includes a circuit board 20 instead of the circuit board 12 of FIG. In the circuit board 20, the through hole 12c of FIG. 1 is removed. Other than that, the configuration of the vehicle-mounted electronic control device 2 is the same as the configuration of the vehicle-mounted electronic control device 1 of FIG.

When the circuit board 20 is used, since there is no through hole 12c in FIG. 1, heat is more likely to be transferred horizontally through the circuit board 12 between the

electronic components

11a and 11b as compared with the case where the circuit board 12 is used. Therefore, when the circuit board 20 is used, the thermal interference between the

electronic components

11a and 11b increases and the temperature rise of the

electronic components

11a and 11b becomes larger than when the circuit board 12 is used.

FIG. 3 is a cross-sectional view showing a configuration in which the in-vehicle electronic control device of FIG. 1 is cut at the positions of the

electronic components

11a and 11b.
In FIG. 3, the circuit board 12 includes

thermal vias

12a and 12b in addition to the configuration of FIG. The

thermal vias

12a and 12b dissipate heat generated in each of the

electronic components

11a and 11b in the vertical direction through the circuit board 12. A filler for improving heat dissipation may be embedded in the

thermal vias

12a and 12b. The

thermal vias

12a and 12b are arranged so as to be directly below the

electronic components

11a and 11b. Further, the

thermal vias

12a and 12b are arranged so as to be directly above the rectangular convex portion 21 when the circuit board 12 is assembled to the housing 10.

Each

electronic component

11a, 11b includes

terminals

17a, 17b. The

electronic components

11a and 11b are electrically joined to the circuit board 12 by soldering the

terminals

17a and 17b to the circuit board 12.

Heat dissipation members

18a and 18b are provided between the

electronic components

11a and 11b and the circuit board 12.

Heat dissipation members

19a and 19b are provided between the rectangular convex portion 21 and the circuit board 12 corresponding to the

electronic components

11a and 11b.

The

heat radiating members

18a, 18b, 19a, 19b dissipate the heat generated by the

electronic components

11a, 11b to the rectangular convex portion 21 by thermal contact. Further, the

heat radiating members

18a and 18b relax the stress applied to the circuit board 12 due to the difference in the coefficient of thermal expansion between the

electronic components

11a and 11b and the circuit board 12.

The heat radiating member 20 is preferably a sheet-like material containing a highly thermally conductive filler in an adhesive, grease, or a thermoplastic resin, or a sheet-like material containing a thermally conductive filler in a highly thermally curable resin such as a silicone resin or an epoxy resin. Is. The high thermal conductivity filler is, for example, metal, alumina or carbon.

FIG. 4 is a plan view showing the configuration of a circuit board on which the

electronic components

11a and 11b of FIG. 3 are mounted.
In FIG. 4, the circuit board 12 includes wiring 16a that electrically connects the

electronic components

11a and 11b. Here, when the

terminals

17a and 17b on the sides facing each other are connected with the intermediate region RM1 in between, the wiring 16a can be arranged in the intermediate region RM1 so as to avoid the position of the through hole 12c. At this time, the wiring 16a can be arranged between the through holes 12c or at a position adjacent to the through holes 12c in the intermediate region RM1. In this case, the through holes 12c can be arranged on both sides of the wiring 16a.

For example, the through holes 12c can be arranged by the number of M (M is a positive integer) row so as to be arranged in a straight line for each row. FIG. 4 shows an example in which two through holes 12c are arranged for four rows so as to be arranged in a straight line for each row. At this time, the wiring 16a can linearly connect the

terminals

17a and 17b on the sides facing each other with the intermediate region RM1 in between. Therefore, the

terminals

17a and 17b can be connected by the shortest path, and high-speed signal transmission between the

terminals

17a and 17b can be realized.

Further, the through hole 12c enables wiring in the intermediate region RM1 and occupies an area where thermal interference between the

electronic components

11a and 11b can be suppressed. At this time, the through hole 12c can occupy an area of 10% or more and 90% or less of the intermediate region RM1. Therefore, even when a resin composite material is used as the material of the housing 10, it is possible to achieve high-speed transmission of signals between the

electronic components

11a and 11b while suppressing the temperature rise of the

electronic components

11a and 11b. ..

Of the opposite sides of the

electronic components

11a and 11b, if both ends of the side of the electronic component 11a are points A and B and both ends of the side of the electronic component 11ab are points C and D, the intermediate region RM1 is the point A, It is set in the area surrounded by B, C, and D.

FIG. 5 is a cross-sectional view showing the heat propagation direction in the thermal interference path between the

electronic components

11a and 11b of FIG.
In FIG. 5, the heat Ha and Hb transmitted horizontally through the circuit board 12 between the

electronic components

11a and 11b are blocked by the through holes 12c. Therefore, the thermal interference between the

electronic components

11a and 11b can be reduced, and the temperature rise of the

electronic components

11a and 11b can be suppressed.

FIG. 6 is a plan view showing a heat dissipation path in the circuit board on which the

electronic components

11a and 11b of FIG. 3 are mounted.
In FIG. 6, the through hole 12c can be arranged at a position where the heat dissipation outside the intermediate region RM1 does not deteriorate and the thermal interference between the

electronic components

11a and 11b can be suppressed. At this time, the through hole 12c can be arranged at a position that does not protrude from the intermediate region RM1 between the mounting region of the electronic component 11a and the mounting region of the electronic component 11b. As a result, it is possible to prevent the heat dissipation paths ka and kb generated from the

electronic components

11a and 11b from being cut off by the through holes 12c, and to ensure the heat dissipation of the heat generated from the

electronic components

11a and 11b. At the same time, thermal interference between the

electronic components

11a and 11b can be reduced.

FIG. 7 is a plan view showing a configuration of a circuit board applied to the in-vehicle electronic control device according to the second embodiment.
In FIG. 7, the circuit board 32 includes a through hole 32c and a wiring 16b instead of the through hole 12c and the wiring 16a of the circuit board 12 of FIG. The wiring 16b includes a bent portion. The bent portion can bend the wiring 16b so that the wiring 16b is not folded back. At this time, the through hole 32c can be arranged on the circuit board 32 along the wiring 16b so as to avoid the position of the wiring 16b.

As a result, even when the

terminals

17a and 17b on the sides facing each other with the intermediate region RM1 in between do not face each other, the increase in the wiring length between the

terminals

17a and 17b is suppressed and the

electronic components

11a and 11b are separated from each other. Thermal interference can be reduced.

FIG. 8 is a plan view showing a configuration of a circuit board applied to the in-vehicle electronic control device according to the third embodiment.
In FIG. 8, the circuit board 42 includes a through hole 42c and a wiring 16c instead of the through hole 12c and the wiring 16a of the circuit board 12 of FIG. The through hole 42c is arranged in the intermediate region RM1 between the mounting region of the electronic component 11a and the mounting region of the electronic component 11b so as to sandwich the wiring region of the wiring 16c. At this time, the wiring 16c can connect the

terminals

17a and 17b in a straight line, and the

terminals

17a and 17b can be connected by the shortest path. Further, the through hole 42c can be arranged so as to leave only the wiring area between the

electronic components

11a and 11b, so that the

terminals

17a and 17b can be connected by the shortest path, and the thermal interference between the

electronic components

11a and 11b can be prevented. It can be suppressed.

FIG. 9 is a cross-sectional view showing a peripheral configuration of

electronic components

11a and 11b applied to the in-vehicle electronic control device according to the fourth embodiment.
In the configuration of FIG. 9, the

heat radiating members

18a and 18b of FIG. 3 are removed, and a gap is provided between the

electronic components

11a and 11b and the circuit board 12. As a result, it is possible to prevent the

electronic components

11a and 11b from coming into contact with the circuit board 12, and it is possible to relieve the stress applied to the

electronic components

11a and 11b.

FIG. 10 is a cross-sectional view showing a peripheral configuration of

electronic components

11a and 11b applied to the in-vehicle electronic control device according to the fifth embodiment.
In the configurations of FIGS. 1 to 9, the circuit board 12 is arranged between the

electronic components

11a and 11b and the rectangular convex portion 21, but in the configuration of FIG. 10, the circuit board 12 is located between the rectangular convex portion 21.

Electronic components

11a and 11b are arranged.

At this time, the

electronic components

11a and 11b can be brought into contact with the rectangular convex portion 21 via the

heat radiating members

19a and 19b, and the heat generated by the

electronic components

11a and 11b can be transferred to the rectangular convex portion 21 without passing through the circuit board 12. It can be escaped to 21. Further, the heat transmitted horizontally through the circuit board 12 between the

electronic components

11a and 11b can be blocked by the through hole 12c, and the thermal interference between the

electronic components

11a and 11b can be reduced.

FIG. 11 is a cross-sectional view showing a peripheral configuration of

electronic components

11a and 11b applied to the in-vehicle electronic control device according to the sixth embodiment.
In FIG. 11, the circuit board 52 includes a recess 12f instead of the through hole 12c of the circuit board 12 of FIG. The recess 12f can be formed on the mounting surface side of the

electronic components

11a and 11b. The number and arrangement positions of the recesses 12f can be set in the same manner as in the through holes 12c. The recess 12f can be used as a low thermal conductivity portion having a smaller thermal conductivity than the circuit board 52.

Here, by providing the circuit board 52 with N recesses 12f, it is possible to reduce the thermal interference between the

electronic components

11a and 11b, suppress the temperature rise of the

electronic components

11a and 11b, and suppress the temperature rise of the

electronic components

11a and 11b. It is possible to suppress an increase in the wiring length of the wiring between the 11a and 11b, and it is possible to realize high-speed transmission of a signal between the

electronic components

11a and 11b.

At this time, in the upper layer of the circuit board 52, the thermal interference path between the

electronic components

11a and 11b is cut off, and in the lower layer of the circuit board 52, the heat generated from the

electronic components

11a and 11b can be released to the rectangular convex portion 21. In addition, the depth of the recess 12f can be adjusted.

In the above-described embodiment, an example in which a through hole or a recess is arranged in the intermediate region RM1 between the mounting region of the electronic component 11a and the mounting region of the electronic component 11b is shown. Through holes and recesses may be mixed and arranged in the intermediate region RM1 between the mounting region of the component 11b. At this time, in the intermediate region RM1 between the mounting region of the electronic component 11a and the mounting region of the electronic component 11b, for example, a recess is arranged at a position close to the

electronic components

11a and 11b and a position far from the

electronic components

11a and 11b. A through hole may be arranged in the.

FIG. 12 is a cross-sectional view showing a peripheral configuration of an electronic component 11 applied to the in-vehicle electronic control device according to the first comparative example.
In FIG. 12, the electronic component 11 is independently mounted on the circuit board 62 instead of the

electronic components

11a and 11b of FIG. In the circuit board 62, the through hole 12c of FIG. 3 is removed. The circuit board 62 includes thermal vias 62a instead of the

thermal vias

12a and 12b of FIG.

The electronic component 11 includes a terminal 17. A heat radiating member 18 is provided between the electronic component 11 and the circuit board 62, and a heat radiating member 19 is provided between the rectangular convex portion 21 and the circuit board 62.

When the electronic component 11 is mounted alone on the circuit board 62, thermal interference does not occur between the electronic components, and the temperature of the electronic component 11 does not rise due to the thermal interference.

FIG. 13 is a cross-sectional view showing the peripheral configurations of the

electronic components

11a and 11b applied to the in-vehicle electronic control device according to the second comparative example.
In FIG. 13, in the circuit board 72, the through hole 12c of FIG. 3 is removed. Other configurations of the in-vehicle electronic control device of FIG. 13 are the same as those of FIG.

FIG. 14 is a plan view showing the configuration of a circuit board on which the

electronic components

11a and 11b of FIG. 13 are mounted.
In FIG. 14, the circuit board 72 has no through hole in the intermediate region RM1 between the mounting regions of the

electronic components

11a and 11b. Therefore, there is no restriction on the arrangement position of the wiring 72a formed in the intermediate region RM1 between the mounting regions of the

electronic components

11a and 11b, and the

electronic components

11a and 11b can be connected by the shortest path.

FIG. 15 is a cross-sectional view showing the heat propagation direction in the thermal interference path between the

electronic components

11a and 11b of FIG.
In FIG. 15, since the circuit board 72 does not have a through hole in the intermediate region RM1 between the mounting regions of the

electronic components

11a and 11b, the heat Ha and Hb generated in the

electronic components

11a and 11b are horizontal to the circuit board 12. It is transmitted in the direction. Therefore, thermal interference occurs between the

electronic components

11a and 11b, and the temperature of the

electronic components

11a and 11b rises due to the thermal interference.

FIG. 16 is a cross-sectional view showing the peripheral configurations of the

electronic components

11a and 11b applied to the in-vehicle electronic control device according to the third comparative example.
In FIG. 16, the circuit board 82 includes a single hole 82a instead of the N through holes 12c in FIG. Other configurations of the in-vehicle electronic control device of FIG. 16 are the same as those of FIG.

FIG. 17 is a plan view showing the configuration of a circuit board on which the

electronic components

11a and 11b of FIG. 16 are mounted.
In FIG. 17, the single hole 82a is formed in the circuit board 82 so as to protrude from the intermediate region RM1 between the mounting regions of the

electronic components

11a and 11b.

By providing the singular hole 82a in the circuit board 82, thermal interference between the

electronic components

11a and 11b can be suppressed, and the temperature rise of the

electronic components

11a and 11b due to the thermal interference can be suppressed. On the other hand, since the single hole 82a protrudes from the intermediate region RM1 between the mounting regions of the

electronic components

11a and 11b, the heat dissipation paths ka and kb in FIG. The sex is reduced. Therefore, in the configuration in which the circuit board 82 is provided with the single hole 82a, the temperature lowering effect due to the suppression of thermal interference between the

electronic components

11a and 11b may be less than the temperature rise effect due to the decrease in heat dissipation of the circuit board 82. The temperature rise of the

components

11a and 11b may increase.

Further, since the single hole 82a is arranged at a position crossing the intermediate region RM1, it is not possible to secure a wiring region for electrically connecting the

electronic components

11a and 11b in the intermediate region RM1.
Therefore, in order to connect the

electronic components

11a and 11b by wiring, it is necessary to bypass the single hole 82a, and the wiring length of the wiring connecting the

electronic components

11a and 11b increases. The transmission speed of the signal between 11b is reduced.

FIG. 18 is a diagram comparing the temperatures of electronic components when a metal and a high thermal conductive resin are used as a housing material for fixing a circuit board on which an electronic component is mounted alone.
In FIG. 18, 3.5 W electrons when a metal having a thermal conductivity of 90 W / m · K and a high heat conductive resin having a thermal conductivity of 10, 20, 30 W / m · K, respectively, are used as housing materials. The component temperatures of the components and 10W electronic components are shown.

When a high thermal conductive resin is used as the housing material, the component temperature of the 3.5W electronic component and the 10W electronic component rises as compared with the case where a metal is used. However, when a high thermal conductive resin having thermal conductivity of 10, 20, and 30 W / m · K is used as the housing material, the component temperature of the 3.5 W electronic component and the 1.0 W electronic component is suppressed to 150 ° C. or less. be able to.

FIG. 19 is a diagram comparing the temperatures of electronic components when a metal and a high thermal conductive resin are used as a housing material for fixing a circuit board on which electronic components are mounted adjacent to each other.
In FIG. 19, when metal is used as the housing material, even when the electronic components are mounted adjacent to each other on the circuit board, the temperature rise is equal to that when the electronic components are mounted alone. It is considered that this is because when metal is used as the housing material, the heat generated in the electronic components is quickly dissipated before the thermal interference occurs between the electronic components.

On the other hand, when a high thermal conductive resin is used as the housing material, the component temperature of the 3.5W electronic component and the 10W electronic component rises as compared with the case where the electronic component is mounted alone. This is because when a high thermal conductive resin is used as the housing material, the heat dissipation property of the heat generated in the electronic components is lowered, and the temperature rises due to the thermal interference between the electronic components.

Therefore, when a high thermal conductive resin is used as the housing material, thermal interference between the electronic components can be suppressed by providing the circuit board with a low thermal conductive portion arranged in the intermediate region between the mounting regions of the electronic components. It is possible to reduce the temperature rise of electronic components. At this time, by arranging the low heat conductive portions discretely in the intermediate region, the wiring region between the electronic components can be provided in the intermediate region, and the wiring length between the electronic components can be shortened.

FIG. 20 is a diagram showing a comparison between the first, second and third embodiments and the numerical examples of the temperature rise of the first, second and third comparative examples.
In FIG. 20, in the first comparative example, as the electronic component 11 of FIG. 12, the component temperature when a 3.5 W electronic component is used and the component temperature when a 1.0 W electronic component is used are shown. In the first, second and third embodiments and the second and third comparative examples, as the

electronic components

11a and 11b of FIGS. 3, 7, 8, 13 and 16, the 3.5 W electronic component and 1 The temperature of each component when using a 0.0 W electronic component is shown. Further, as a housing material, a high thermal conductivity resin having a thermal conductivity of 10 W / m · K was used.

In the second comparative example, as shown in FIG. 15, thermal interference occurs between the

electronic components

11a and 11b, which causes a temperature rise of 3 ° C. as compared with the first comparative example. In the third comparative example, since there is a single hole 82a in the intermediate region RM1 between the mounting regions of the

electronic components

11a and 11b, thermal interference can be suppressed between the

electronic components

11a and 11b, as compared with the first comparative example. The temperature rise is suppressed to 1.5 ° C. for 3.5W electronic components and 2.5 ° C. for 1.0W electronic components.

In the first, second and third embodiments, since there are N through holes in the intermediate region RM1 between the mounting regions of the

electronic components

11a and 11b, the 3.5 W electronic component has 1 as compared with the first comparative example. For electronic components at 5.5 ° C and 1.0 W, the temperature rise is suppressed to 2.5 ° C. At this time, the N through holes are arranged at positions where the component temperatures of the 3.5 W electronic component and the 1.0 W electronic component are 150 ° C. or lower.

Here, even in a configuration in which N through holes are provided in the intermediate region RM1 between the mounting regions of the

electronic components

11a and 11b, a singular hole is provided across the intermediate region RM1 between the mounting regions of the

electronic components

11a and 11b in FIG. It is possible to obtain the same effect of suppressing temperature rise as the configuration provided with 82a.

21 (a) to 21 (c) are plan views showing other examples of intermediate regions between mounting regions of electronic components.
In FIG. 21A, it is assumed that the

electronic components

11d and 11e adjacent to each other are staggered and arranged on the circuit board. At this time, the intermediate region RM2 between the mounting regions of the

electronic components

11d and 11e can be set within the region including all the linear paths that cause thermal interference between the

electronic components

11a and 11b. As a result, by providing through holes or recesses discretely in the intermediate region RM2 of the circuit board, the wiring region between adjacent electronic components is secured in the intermediate region RM2, and thermal interference between the electronic components is effectively performed. It can be suppressed.

In FIG. 21B, it is assumed that

electronic components

11f and 11g having different sizes are arranged adjacent to each other on the circuit board. At this time, the intermediate region RM3 between the mounting regions of the

electronic components

11f and 11g can be set within the region including all the linear paths that cause thermal interference between the

electronic components

11f and 11g. As a result, by providing through holes or recesses discretely in the intermediate region RM3 of the circuit board, the wiring region between adjacent electronic components is secured in the intermediate region RM3, and thermal interference between the electronic components is effectively performed. It can be suppressed.

In FIG. 21C, it is assumed that the three

electronic components

11h, 11i, and 11j are arranged adjacent to each other on the circuit board. At this time, the intermediate region RM4 between the mounting regions of the three

electronic components

11h, 11i, 11j is set within the region including all the linear paths that cause thermal interference between the

electronic components

11h, 11i, 11j. Can be done. At this time, the intermediate region RM4 can be continuously set for the three

electronic components

11h, 11i, and 11j. As a result, through holes or recesses are provided discretely in the intermediate region RM4 of the circuit board, so that the wiring region between adjacent electronic components is secured in the intermediate region RM4, and thermal interference between the electronic components is effectively performed. It can be suppressed.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

1 In-vehicle electronic control device, 11a to 11c electronic components, 12 circuit boards, 13 bases, 14 covers, 15 connectors, 15a pin terminals, 16a to 16c wiring, 17a, 17b terminals, 12a, 12b thermal vias, 12c through holes, 18a , 18b, 19a, 19b heat dissipation member, 21 rectangular convex part, 22 screws

Claims

A circuit board on which the first electronic component and the second electronic component are mounted adjacent to each other,
A housing for fixing the circuit board and
It is provided on the circuit board and has a low thermal conductivity portion having a smaller thermal conductivity than the circuit board.
The low heat conductive portion is an electronic control device discretely arranged in an intermediate region between the mounting region of the first electronic component and the mounting region of the second electronic component.
The electronic control device according to claim 1, wherein the low heat conductive portion is a through hole or a recess provided in the circuit board.
The circuit board includes wiring that electrically connects the first electronic component and the second electronic component.
The electronic control device according to claim 1, wherein the wiring is arranged in the intermediate region so as to avoid the position of the low heat conductive portion.
The electronic control device according to claim 3, wherein the wiring is arranged at a position between the low heat conductive portions or adjacent to the low heat conductive portions in the intermediate region.
The electronic control according to claim 3, wherein the low heat conductive portion enables the wiring in the intermediate region and occupies an area capable of suppressing thermal interference between the first electronic component and the second electronic component. apparatus.
The electronic control device according to claim 5, wherein the low heat conductive portion occupies an area of 10% or more and 90% or less of the intermediate region.
The electronic control device according to claim 1, wherein the thermal conductivity of the housing is 30 W / m · K or less.
The electronic control device according to claim 1, wherein the calorific value of the first electronic component and the calorific value of the second electronic component are different from each other.
The electronic control device according to claim 1, wherein the low heat conductive portion is arranged at a position where the component temperature of the first electronic component and the component temperature of the second electronic component are 150 ° C. or lower.
The low thermal conductive portion is claimed at a position where the temperature lowering effect due to the suppression of thermal interference between the first electronic component and the second electronic component exceeds the temperature raising effect due to the reduced heat dissipation of the circuit board. Item 1. The electronic control device according to item 1.
The first aspect of the present invention, wherein the low heat conductive portion is arranged at a position where the heat dissipation property outside the intermediate region is not deteriorated and thermal interference between the first electronic component and the second electronic component can be suppressed. Electronic control device.