JP4983653B2 - Electronic circuit equipment - Google Patents

Description

  The present invention relates to an electronic circuit device in which an electronic circuit unit housed in a housing space formed by a case body and a cover member is sealed with a sealing resin.

As a prior art, there is an electronic circuit device disclosed in Patent Document 1 below. In this electronic circuit device, the electronic circuit unit housed in the case is sealed with a sealing resin to protect the electronic circuit unit.
JP 2002-343907 A

  However, the space for storing the electronic circuit portion is configured by the case body and the cover member that closes the opening of the case body, and the liquid resin that serves as the sealing member is disposed at the inner peripheral end (contact surface) of the boundary surface between the case body and the cover member. In the case of filling up from above the inner end portion of the liquid crystal, there is a problem that the liquid resin may leak to the outside from the contact portion between the case body and the cover member.

  The present invention has been made in view of the above points, and an electronic circuit capable of preventing liquid resin serving as a sealing member from leaking from a contact portion between a case body that houses the electronic circuit portion and a cover member. An object is to provide an apparatus.

In order to achieve the above object, in the invention described in claim 1,
An electronic circuit part forming an electronic circuit;
A case body that houses the electronic circuit section;
A cover member that closes the opening of the case body;
A liquid resin filled in the case body is cured, and includes a sealing member for sealing the electronic circuit part,
An electronic circuit device in which the upper surface when the sealing member is filled in a liquid resin state is above the inner end of the contact portion where the case body and the cover member contact each other,
It is characterized in that a fluororesin coating is applied to a portion to be a contact portion of the case body.

  According to this, the liquid resin that tries to enter the clearance of the contact portion between the case body and the cover member is repelled by the fluororesin coating applied to the portion that becomes the contact portion with the cover member of the case body, and the liquid resin is contacted with the contact portion. Can be prevented from leaking outside.

  Further, the invention according to claim 2 is characterized in that the case body is provided with a fluororesin coating only on a portion that becomes a contact portion with the cover member.

  According to this, since the fluororesin is coated only on the part necessary for preventing leakage of the liquid resin, the amount of the fluororesin used can be reduced.

  Further, the invention described in claim 3 is characterized in that a fluororesin coating is also applied to a portion to be a contact portion of the cover member.

  According to this, the liquid resin that tries to enter the clearance of the contact portion between the case body and the cover member is reliably repelled by the fluororesin coating applied to both the case body and the cover member, so that the liquid resin is exposed from the contact portion to the outside. Leakage can be prevented more reliably.

  According to a fourth aspect of the present invention, the electronic circuit part has a sensor part exposed on the outer surface of the case body.

  According to this, it can prevent that liquid resin adheres to the sensor part exposed to the outer surface of the leak case body outside.

  When the sensor unit performs at least one of transmission and reception of ultrasonic waves as in the invention described in claim 5, if the resin adheres to the sensor unit, the ultrasonic vibration is inhibited and functions. There is a possibility that it will be defective, and the effect of preventing the resin from adhering to the sensor part is extremely great.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an appearance of an ultrasonic sensor device 1 which is an electronic circuit device according to an embodiment to which the present invention is applied. 2 and 3 are perspective views for explaining an assembly process of the ultrasonic sensor device 1, and FIG. 4 is a cross-sectional view of a main part of the ultrasonic sensor device 1.

  An ultrasonic sensor device 1 shown in FIG. 1 includes a case 20 (corresponding to a case body) and a cover 30 (corresponding to a cover member) forming an outer casing, and an electronic circuit unit 10 (see FIG. 2) housed in the casing. ) And a sealing resin 40 (corresponding to a sealing member) for protecting the electronic circuit unit 10 from vibration, water, dust, and the like.

  The electronic circuit unit 10 has a sensor unit 11 exposed on the outer surface of the case 20, and the ultrasonic sensor device 1 is mounted on a bumper or the like of a vehicle and transmits / receives ultrasonic waves by the sensor unit 11, and This is a device for detecting the distance to an obstacle or the like.

  The case 20 has a shape in which a rectangular tube portion 21 on the upper side in the drawing and a cylindrical portion 22 on the lower side in the drawing are connected, and as shown in FIG. 2, the electronic circuit portion 10 is accommodated therein. Yes. And the sensor part 11 is accommodated in the cylindrical part 22, and the front-end | tip part of the sensor part 11 is exposed in the bottom face of the cylindrical part 22. FIG. In addition, a connector 23 is provided on a side surface of the rectangular tube portion 21, and a terminal portion of the connector 23 is electrically connected to the electronic circuit portion 10.

  As shown in FIG. 2, the case 20 is configured such that the upper side of the rectangular tube portion 21 is open, and a cover 30 is mounted inside the opening edge portion 24. The cover 30 has a substantially rectangular shape corresponding to the opening shape of the case 20, and an injection port 31 for injecting a liquid resin 41 (see FIG. 4) serving as the sealing resin 40 at a position slightly shifted from the center. And a fitting wall portion 32 that fits inside the opening edge 24 of the case 20 is formed at the peripheral portion.

  Both the case 20 and the cover 30 are formed by injection molding of a resin material (for example, polybutylene terephthalate resin). In this example, the case 20 and the cover 30 are each formed by a plurality of molds.

  A part of the opening edge 24 of the case 20 on the side where the connector 23 is provided is a lower portion 241 having a lower height than the remaining portion. This low-order part 241 is for facilitating processing in the case 20 (for example, electrical connection processing between the electrical circuit unit 10 and the connector 23 terminal unit) after the electronic circuit unit 10 is housed in the case 20. Is formed.

  FIG. 4 is a view showing a vertical cross section of the lower portion 241 region in a state where the case 20 and the cover 30 are assembled.

  As shown in FIG. 4, the opening edge 24 of the case 20 is formed with a plurality of step portions so that the height dimension (the vertical dimension in the drawing) decreases toward the inside. On the other hand, the fitting wall portion 32 of the cover 30 has a plurality of height dimensions (vertical dimensions in the drawing) that increase toward the inside so as to correspond to the stepped portion on the inner side surface of the opening edge 24 of the case 20. A step is formed.

  Then, the cover 30 is mounted so as to be fitted inside the case 20, and an inner side surface having a step portion of the case 20 opening edge portion 24 and an outer side surface having a step portion of the cover 30 fitting edge portion 32 are formed. A contact portion 50 is formed that contacts and bends. The sealing resin 40 described above is filled so as to fill the storage space of the electronic circuit unit 10 formed by the case 20 and the cover 30, and is located above the inner end 501 of the contact part 50 between the case 20 and the cover 30. To the inlet 31 of the cover 30 located in

  Here, the contact surface 25 of the case 20 out of the surface on the case 20 side and the surface on the cover 30 side, that is, the contact surface 25 of the case 20 and the contact surface 33 of the cover 30 forming the contact portion 50 is shown in FIG. And as shown in FIG. 4, the coating layer 26 formed by coating a fluororesin is formed.

  Next, a method for assembling the ultrasonic sensor device 1 having the above configuration will be briefly described.

  First, as shown in FIG. 2, the electronic circuit unit 10 is mounted in the case 20 in which the coating layer 26 is formed only on the contact surface 25 inside the opening edge 24. The coating layer 26 is formed by applying a coating liquid composed of a fluororesin and a solvent only to the contact surface 25 and drying it with warm air. Next, the cover 30 is fitted and mounted inside the opening edge 24 of the case 20.

  Further, as shown in FIG. 3, a liquid that becomes a sealing resin 40 by using a filling machine 100 such as a dispenser in an electronic circuit unit 10 storage space formed by the case 20 and the cover 30 from the inlet 31 of the cover 30. The resin 41 is filled. In this example, a urethane resin is used as the liquid resin 41. As shown in FIG. 4, the liquid resin 41 is filled up to the opening position of the injection port 31 where the upper surface 411 is above the inner end 501 of the contact portion 50. Incidentally, the upper surface 411 of the liquid resin 41 is not only above the inner end 501 of the contact part 50 but also above the outer end higher than the inner end 501 of the contact part 50.

  When the filling of the liquid resin 41 into the electronic circuit unit 10 storage space is completed, the resin is heat-cured (for example, heat-cured at 80 ° C. for about 10 minutes) to cure the liquid resin 41 to obtain the sealing resin 40.

  According to the above-described configuration and assembly method, the fluororesin coating layer 26 is formed on the contact surface 25, which is a portion to be the contact portion 50 of the case 20. Thus, when the storage space of the electronic circuit unit 10 is filled with the liquid resin 41, the clearance of the contact part 50 between the case 20 and the cover 30 enters the clearance from the inner end 501 and crawls outward due to capillary action. The liquid resin 41 intended to be repelled by the coating layer 26 can prevent the liquid resin 41 from leaking from the contact portion 50 to the outside.

  Immediately after the heat curing of the liquid resin 41 is started, the viscosity drop due to the plasticization of the polymer due to the temperature rise is larger than the viscosity increase due to the bonding between the polymers due to the heat curing reaction, and the liquid resin 41 is larger than the time of the injection. Viscosity decreases temporarily. Even when the liquid resin 41 has a minimum viscosity, the liquid resin 41 can be prevented from entering the contact portion 50 clearance.

  When the case 20 and the cover 30 are each molded with a plurality of molds as in this embodiment, the contact portion that can suppress the intrusion of the liquid resin 41 regardless of the combination of the case 20 and the cover 30. If it is going to obtain 50 adhesion | attachment states, there will be a problem that adjustment of a metal mold | die and adjustment of molding conditions will require time and process management will become very complicated.

  However, if the coating layer 26 of fluororesin is employed, specifically, even if the clearance of the contact portion 50 is several tens to 100 μm, the liquid resin can be formed by merely forming the coating layer 26 having a thickness of several μm to 10 μm. The present inventors have confirmed that it is possible to prevent 41 from entering the clearance 50 of the contact portion.

  When the fluororesin coating layer 26 is not formed, for example, as shown in FIG. 5, the liquid resin 41 serving as the sealing resin 40 enters the clearance of the contact portion 950 between the case 920 and the cover 30 and is externally applied. The liquid resin sag (liquid mass) 941 may be formed on the outer surface of the case 920 (see also FIG. 6). This sagging may cause an obstacle when the ultrasonic sensor device 1 is mounted on a vehicle, or the sensor may cause a malfunction when attached to the sensor unit.

  On the other hand, according to this embodiment, by preventing leakage of the liquid resin 41 to the outside, the liquid resin 41 adheres to the outer surface of the case 20 and becomes an obstacle during mounting, or the outer periphery of the case 20 It is possible to reliably prevent the resin from adhering to the sensor unit 11 exposed on the surface and hindering transmission / reception of ultrasonic waves.

  Further, since the coating layer 26 is formed only on the contact surface 25 of the case 20, the amount of the fluororesin used is small, and the coating layer 26 that repels the liquid resin 41 is not formed on any part other than the contact part 50. Thus, it is easy to improve the adhesion between the sealing resin 40 and the case 20 or the cover 30. Thereby, high sealing performance by the sealing resin 40 can be obtained.

  Furthermore, since the contact surface 25 forming the coating layer 26 is the inner peripheral surface of the case 20, the outer peripheral surface of the case 20 can be gripped when the fluororesin coating liquid is applied and dried, and the degree of freedom of the gripping position is increased. Since it is large, the coating layer 26 forming step can be easily performed.

(Other embodiments)
In the above embodiment, the coating layer 26 of fluororesin is formed only on the contact surface 25 of the case 20, but the coating layer 26 may be formed on other than the contact surface 25 of the case 20. .

  In the above embodiment, the coating layer 26 of fluororesin is formed only on the contact surface 25 of the case 20, but it may be formed also on the contact surface 33 of the cover 30. By forming the fluororesin layer on both contact surfaces 25 and 33, the liquid resin 41 can be reliably repelled, and the liquid resin 41 can be more reliably prevented from leaking from the contact portion 25 to the outside.

  In the above embodiment, the case where the present invention is applied to the ultrasonic sensor device 1 has been described. However, the present invention may be applied to other sensor devices. In particular, if the sensor unit is a sensor device that is exposed on the outer surface of the case body, resin adhesion to the sensor unit can be prevented, and it is very effective without causing functional failure of the sensor unit. In addition, the present invention is widely applicable and effective as long as it is an electronic circuit device that seals the electronic circuit portion housed in the space formed by the case body and the cover member, not limited to the sensor device.

1 is a perspective view illustrating an appearance of an ultrasonic sensor device 1 that is an electronic circuit device according to an embodiment to which the present invention is applied. 5 is a perspective view for explaining a part of the assembly process of the ultrasonic sensor device 1. FIG. 5 is a perspective view for explaining a part of the assembly process of the ultrasonic sensor device 1. FIG. 1 is a cross-sectional view of a main part of an ultrasonic sensor device 1. It is sectional drawing of the site | part of the comparative example corresponding to the principal part of FIG. It is an external appearance perspective view of the site | part of the comparative example shown in FIG.

Explanation of symbols

1 Ultrasonic sensor device (electronic circuit device)
10 Electronic circuit part 11 Sensor part 20 Case (case body)
25, 33 Contact surface (site to be the contact portion 50)
26 Coating layer (fluorine resin coating)
30 Cover (cover member)
40 Sealing resin (sealing member)
41 liquid resin 50 contact part 411 upper surface (upper surface of liquid resin 41)
501 Inner end (inner end of contact 50)

Claims (5)

An electronic circuit part forming an electronic circuit;
A case body that houses the electronic circuit portion therein;
A cover member for closing the opening of the case body;
A liquid resin filled in the case body is cured, and includes a sealing member for sealing the electronic circuit unit,
An electronic circuit device in which an upper surface when the sealing member is filled in the case body in the state of the liquid resin is higher than an inner end portion of a contact portion where the case body and the cover member are in contact with each other. There,
An electronic circuit device, characterized in that a fluororesin coating is applied to a portion of the case body that becomes the contact portion.   2. The electronic circuit device according to claim 1, wherein the fluororesin coating is applied only to a portion that becomes the contact portion of the case body.   3. The electronic circuit device according to claim 1, wherein the fluororesin coating is also applied to a portion that becomes the contact portion of the cover member. 4.   The electronic circuit device according to any one of claims 1 to 3, wherein the electronic circuit unit includes a sensor unit exposed on an outer surface of the case body.   The electronic circuit device according to claim 4, wherein the sensor unit performs at least one of transmission and reception of ultrasonic waves.

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