WO2019230170A1

WO2019230170A1 - Vehicle-mounted electronic device

Info

Publication number: WO2019230170A1
Application number: PCT/JP2019/013252
Authority: WO
Inventors: 侯宏松岡
Original assignee: 株式会社デンソー
Priority date: 2018-05-30
Filing date: 2019-03-27
Publication date: 2019-12-05
Also published as: JP2019206295A; JP7192252B2

Abstract

This vehicle-mounted electronic device (1), which is an electronic device mounted on a vehicle, is provided with: a case (2); a circuit board (3) provided inside the case; and a protective cover (11) provided so as to cover at least a portion of the circuit board, wherein the cover comprises a molded article made of a plastic sheet and has an integrated front surface-side protrusion section (12) and rear surface-side protrusion section (13). The front surface-side protrusion section abuts the inner wall surface of the case, and the rear surface-side protrusion section abuts the front surface of the circuit board.

Description

Automotive electronic devices

Cross-reference of related applications

This application is based on Japanese Application No. 2018-103502 filed on May 30, 2018, the contents of which are incorporated herein by reference.

The present disclosure relates to an in-vehicle electronic device mounted on a vehicle such as an automobile.

For example, various electronic devices such as a display unit and an engine control ECU are mounted on a vehicle such as an automobile. This type of electronic device is configured by housing a circuit board in a case, but in particular, there is a device that includes a cooling fan and takes outside air into the case to cool components. In this case, if high-humidity air enters the case at a low temperature, condensation may occur on the surface of the circuit board, which may lead to corrosion. Therefore, conventionally, a moisture-proofing agent is generally applied to a portion on the circuit board where there is a risk of condensation.

Further, in order to prevent intrusion of dust and the like into the surface portion of the circuit board in the electronic device, for example, the following configuration is also considered. That is, in Patent Document 1, in the optical disc apparatus, protection made of a thin stainless steel plate is considered. Providing a cover is disclosed. Alternatively, Patent Document 2 discloses that, in a digital camera, the optical filter is covered with an elastomer such as a rubber material in order to prevent dust from entering the optical filter portion.

JP 2004-110973 A Japanese Patent No. 5901347

However, as described above, in the configuration in which the moisture-proofing agent is applied to the circuit board, there are circumstances in which the man-hours for the application work and management are increased, and the manufacturing cost is increased. Moreover, if a moisture-proofing agent adheres to a connector etc., there exists a possibility of causing a malfunction. In the configuration in which the metal protective cover is provided, the protective cover itself is expensive and it is difficult to ensure a small clearance from the circuit board, which causes problems such as poor insulation. Or in the structure covered with an elastomer, there existed a problem of a deformation | transformation and deterioration of a rubber material in the use in the high temperature and high humidity environment of a vehicle.

The present disclosure is intended to provide an in-vehicle electronic device that can effectively protect a circuit board from dew condensation, dust, and the like, but can simply complete the configuration for that purpose.

In the first aspect of the present disclosure, the in-vehicle electronic device is an electronic device mounted on a vehicle, and covers a case, a circuit board provided in the case, and at least a part of the circuit board. A protective cover provided on the surface of the case. The cover is made of a molded product of a plastic sheet, and integrally includes a front-side protrusion and a back-side protrusion, and the front-side protrusion is an inner part of the case. Abutting against the wall surface, the back side protrusion is provided in a state of abutting against the surface of the circuit board.

According to this, since the circuit board is covered with the protective cover, it is possible to prevent condensation on the circuit board and prevent dust from adhering. At this time, since the protective cover is formed of a molded product of a plastic sheet, a three-dimensional shape following the surface shape of the circuit board can be easily formed. Therefore, the cover itself can be thinned and arranged with a small clearance. Moreover, it can be made inexpensively. Since the cover is made of an insulating material, it is a matter of course that, unlike a metal cover, even if the clearance between the circuit board and the circuit board is reduced, the problem of poor insulation does not occur.

Here, when a plastic cover is provided in the case, there is a concern about generation of vibration sound of the cover due to vehicle vibration. However, the front side projection provided on the front side of the cover contacts the inner wall surface of the case, and the rear side projection provided on the back side of the cover contacts the surface of the circuit board. It becomes the form which is pinched | interposed and hold | maintained between board | substrates. Thereby, the vibration of the cover can be regulated to prevent the generation of abnormal noise. Therefore, it is possible to effectively protect the circuit board from dew condensation, dust, and the like, while obtaining an excellent effect that the configuration for the circuit board can be easily completed.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. The drawing
FIG. 1 shows an embodiment and is an exploded perspective view of an in-vehicle electronic device. FIG. 2 is a perspective view of the main part with the second case removed, FIG. 3 is a perspective view of a state in which a cover is disposed on the second circuit board, FIG. 4 is a cross-sectional view showing the surface side protrusion portion. FIG. 5 is a cross-sectional view showing the rear surface side protruding portion.

Hereinafter, an embodiment in which the vehicle-mounted electronic device is applied to, for example, a vehicle display unit will be described with reference to the drawings. A vehicle-mounted electronic device 1 (hereinafter simply referred to as “electronic device 1”) according to the present embodiment is composed of, for example, a display unit that constitutes a navigation system, and is mounted on a central portion of an instrument panel of an automobile. In the drawings, the liquid crystal panel side that is disposed on the front side, that is, the front side in an actual vehicle-mounted state, that is, in a used state, is shown in a form in which the liquid crystal panel is placed downward.

FIG. 1 schematically shows the overall appearance of the electronic device 1. The electronic device 1 is configured by

housing circuit boards

3 and 4 formed by mounting various components on a printed wiring board in a case 2. At this time, in the present embodiment, two

circuit boards

3 and 4 are provided in the case 2, of which the front side in the figure, that is, the lower side circuit board in the use state, is the first circuit board 3, the back side, In other words, the upper circuit board is referred to as a second circuit board 4 in use.

The case 2 has a substantially rectangular box shape that is thin in the vertical direction in the figure, that is, in the front-rear direction in the state of use, and the lower first case 5 in the figure and the upper second case 6 in the figure are abutted and joined. Configured. Of these, as shown in part in FIG. 2, the first case 5 is made of, for example, plastic and has a thin, substantially rectangular box shape with an upper surface opened in the figure. Although not shown, a liquid crystal panel is provided on the lower surface side of the first case 5, that is, on the front surface side when the vehicle is mounted.

The second case 6 is made of, for example, a metal and has a rectangular lid shape whose bottom surface is opened in the figure, and is provided so as to close the opening part on the top surface in the figure of the first case 5. A fan mounting portion 6a is provided at the center of the second case 6, and a cooling fan device (not shown) is mounted. Further, the second case 6 is provided with an opening 6b or the like in which a plurality of connectors 8 (only part of which are shown) for external connection are disposed. In addition, in the figure of the 2nd case 6, the extension part 6c extended to the near side by the figure is integrally provided in the lower part of the front end.

At this time, an external airflow inlet 7 is provided between the first case 5 and the extended portion 6c of the second case 6 on the front surface, that is, in the use state in the drawing of the case 2, at the bottom surface. When the fan device is driven, the outside air is sucked into the case 2 from the outside air flow inlet 7 as indicated by an arrow A in FIG. The sucked air contributes to the cooling of the internal electronic components and the like, and is then discharged to the upper surface side, that is, the rear surface side in the use state.

As shown in FIGS. 2 and 3, the first circuit board 3 has a horizontally long shape, and a plurality of components 9 (only a part thereof) constituting an electric circuit are mounted on the upper surface thereof. ing. In this case, the first circuit board 3 is disposed on the near side in the figure in the first case 5 of the case 2, and therefore the upper surface portion of the first circuit board 3 is located at a portion facing the external air flow inlet 7. Has been placed. As shown in FIG. 1, the second circuit board 4 has a substantially square shape larger in the front-rear direction than the first circuit board 3 in the figure, and the first circuit board 3 in the first case 5 of the case 2. It is arrange | positioned and located in the back | inner side. The connector 8 is mounted on the second circuit board 4.

In the present embodiment, a protective cover 11 is provided so as to cover the upper surface of the first circuit board 3 among the

circuit boards

3 and 4. As shown in FIGS. 1 to 3, the cover 11 is a molded product of a plastic sheet. The cover 11 has a shape that covers the entire upper surface of the first circuit board 3 including the electronic components 9 on the upper surface of the first circuit board 3 so as to cover almost the entire upper surface with a slight clearance. It is formed in a rectangular lid shape. More specifically, the plastic sheet constituting the cover 11 is made of, for example, polypropylene or PP sheet or film having a thickness of 0.5 mm, and the cover 11 is formed by so-called vacuum forming.

As is well known, vacuum molding is a method in which a sheet is heated and softened, and the sheet is molded by being brought into close contact with the surface of a mold by vacuuming. As shown in FIGS. 2 and 3, among the components 9 mounted on the upper surface of the first circuit board 3, an opening 11 a is formed in the cover 11 for a part 9 having a large height. The component 9 is disposed so as to protrude upward from the opening 11a.

Further, the cover 11 is integrally formed with a front side protrusion 12 positioned on the front surface side, and is integrally formed with a back surface protrusion 13 positioned on the back surface side. Of these, as shown in FIGS. 3 and 4, one surface-side protruding portion 12 is provided at a position along the center line C of the front side portion of the cover 11, for example, in a form that bulges in a circle with a diameter of about 4 mm. ing. In addition, the projecting dimension in the thickness direction (upward in the drawing) of the front side protruding portion 12 is, for example, about 0.6 mm. The front end of the surface side protrusion 12 abuts on the case 2, that is, the inner wall surface of the extension 6 c of the second case 6.

As shown in FIG. 5, each of the two rear surface protruding portions 13 is provided side by side in the horizontal direction at a position symmetrical to the left and right with respect to the center line C in the front end portion of the cover 11. It has been. These back side protrusions 13 are formed so that the tip is rounded and protrudes to the back side, and the protruding dimension in the thickness direction (downward in the figure) is, for example, about 0.6 mm. Has been. These back side protrusions 13 are in contact with the surface of the first circuit board 3 at their tips. Thus, the cover 11 is sandwiched and held between the second case 6 and the first circuit board 3. In this case, the amount of interference in the height direction in the drawing of the front surface side protruding portion 12 and the back surface side protruding portion 13 is, for example, about 0.3 mm.

At this time, screw insertion holes are formed in the first circuit board 3 at the corners on both sides and on the other corners. Thus, as shown in FIG. 2 and the like, the screw boss portion (not shown) formed on the inner wall portion of the first case 5 is fixed by screws 14 such as screws. In the present embodiment, as shown in FIG. 3, the cover 11 is also formed with screw insertion holes 11 b at four corners or the like at positions overlapping the screw insertion holes of the first circuit board 3. . The cover 11 is fixed to the first case 5 together with the first circuit board 3 by so-called co-tightening with the screws 14.

Next, the operation and effect of the electronic device 1 configured as described above will be described. In the electronic device 1 having the above-described configuration, the first circuit board 3 is covered with the protective cover 11, thereby preventing condensation on the first circuit board 3 and preventing dust from adhering. At this time, since the cover 11 is formed of a molded product of a plastic sheet, a three-dimensional shape following the surface shape of the first circuit board 3 can be easily formed. Thus, the cover 11 can be disposed with a small clearance and a small clearance. Further, the cover 11 can be made inexpensively. Since the cover 11 is made of an insulating material, it is a matter of course that the problem of insulation failure does not occur even if the clearance between the cover 11 and the first circuit board 3 is reduced, unlike a metal cover.

Here, when the plastic cover 11 is provided in the case 2, there is a concern about the generation of vibration sound of the cover 11 due to vehicle vibration. However, the front side protrusion 12 provided on the front side of the cover 11 contacts the inner wall surface of the extension 6c of the second case 6, and the back side protrusion 13 provided on the back side of the cover 11 is the first. It contacts the surface of the circuit board 3. As a result, the cover 11 is sandwiched and held between the case 2 and the first circuit board 3, and the vibration of the cover 11 can be regulated to prevent the generation of abnormal noise. Therefore, according to the present embodiment, while the circuit board 3 can be effectively protected from dew condensation, dust, and the like, it is possible to obtain an excellent effect that the configuration for that can be easily completed.

Particularly in the present embodiment, a fan device is provided, and the outside air is taken in from the outside air flow inlet 7 provided in the case 2. The cover 11 is provided so as to cover the upper surface of the first circuit board 3, which is a portion facing the external air flow inlet 7. As a result, the surface portion of the first circuit board 3, which is the portion where condensation is most likely to occur in the case 2, can be covered with the cover 11. Therefore, even if dew condensation occurs, it is on the surface side of the cover 11, so that dew condensation on the first circuit board 3 and problems associated therewith can be prevented in advance.

Further, in the present embodiment, one front side protruding portion 12 is provided at a position along the center line C in the cover 11, and a plurality of back side protruding portions 13 are arranged on the left and right sides of the center line C of the cover 11. It was arranged at a symmetrical position. As a result, the cover 11 is stably held between the case 2 and the first circuit board 3.

In this embodiment, polypropylene is adopted as the plastic sheet constituting the cover 11. Polypropylene as a material is inexpensive and lightweight, has excellent insulating properties, and can obtain a certain strength, that is, high rigidity even with a thin sheet. Good formability such as vacuum forming. Advantages such as being stronger and more stable against heat and temperature change than rubber or the like, and having a smaller heat capacity than metal can be obtained.

In the above embodiment, when the cover 11 is attached, the first case 5 of the case 2 is screwed together with the first circuit board 3, so-called joint fastening. On the other hand, it is also possible to adopt a configuration in which such a fixing means is not particularly provided and held between the case and the circuit board. Moreover, in the said embodiment, although the cover 11 was made from PP, you may comprise from a polyethylene terephthalate, ie, PET, and can obtain the effect | action and effect similar to the case made from PP. Even if the fan device is not provided, the circuit board can be protected from dew condensation, dust and the like by providing the cover 11 in the same manner.

In addition, although applied to the display unit in the above embodiment, the present invention can be applied to various electronic devices for vehicles of various uses and types such as an engine ECU. Of course, various changes can be made to the shape of the case and the arrangement of the external airflow inlet. Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

Claims

An electronic device (1) mounted on a vehicle,
Case (2),
A circuit board (3) provided in the case;
A protective cover (11) provided to cover at least a part of the circuit board,
The cover is made of a molded product of a plastic sheet, and integrally has a front side protrusion (12) and a back side protrusion (13),
The vehicle-mounted electronic device provided in the state which the said surface side protrusion part contact | abutted to the inner wall surface of the said case, and the said back surface side protrusion part contact | abutted to the surface of the said circuit board.
The in-vehicle use according to claim 1, wherein the case is provided with an external air flow inlet for introducing external air, and the cover is provided so as to cover at least a portion of the circuit board facing the external air flow inlet. Electronic equipment.
3. The vehicle-mounted electronic device according to claim 1, wherein one or both of the front-side protrusion and the rear-side protrusion are provided at positions symmetrical with respect to a center line in the cover.
4. The on-vehicle electronic device according to claim 1, wherein the plastic sheet constituting the cover is made of polypropylene or polyethylene terephthalate.