JP6685252B2 - Electronic control unit - Google Patents

Description

  The present invention relates to the structure of an in-vehicle electronic control device.

  2. Description of the Related Art In recent years, as the output of engines in automobiles has increased and the performance of vehicles has increased, the mounting environment in the engine room and the drive conditions for electronic control devices have become more and more severe. On the other hand, cost reduction of vehicles is also progressing. Therefore, there is an increasing demand for high reliability / low cost even in the electronic control device mounted in the engine room.

  The housing of an electronic control device, such as an engine control unit that controls the engine, is made up of a cover and base that are mainly made of aluminum die casting, sheet metal, resin, etc. It is fastened by caulking and snap fit. With regard to screwing, a plurality of screws are tightened in the process, and thus the work cost of the screw tightening process is required in addition to the cost of a single screw. With respect to the heat crimping, no fastening parts are required, but since the resin portion is melted by heat and crimped, the tact of the crimping process becomes long and the working cost is high. Compared to these fastening methods, snap fitting does not require fastening parts, and the assembly is completed by engaging the snap fit in the process, so the assembly tact is short and the cheapest fastening is possible. .

  However, the snap fit has a structure in which the engaging claw is fastened by being engaged with the engaged body when the engaging claw opens outward and returns to the original state, so that the engaging claw and the engaged body are securely engaged. In order to be performed, a certain amount of play is required between the engaging claw and the engaged body. Therefore, this is a fastening method in which variations in the mounting of the housing are increased by the amount of the play.

  On the other hand, in an engine control unit, etc., one case is attached with an electronic circuit board on which electronic components having heat generating parts are mounted, and the other case is provided with a metal member for heat dissipation, and the two cases are assembled. At this time, some electronic components radiate heat by applying a heat radiating member between the metal member and the heat generating component.

  In such a structure, the heat dissipation member sandwiched between the two housings is greatly affected by the assembly variation of the housings, so the thickness of the heat dissipation member also becomes thicker, resulting in higher thermal resistance and heat dissipation. Sex decreases. Therefore, when the snap-fit structure is applied, the problem is that the assembly variation becomes large.

  As a method of reducing the variation in the assembling of the casing, for example, a structure in which a positioning mechanism is provided in the snap fit described in Patent Document 1 is known.

JP 2012-70508 JP

  The structure of Patent Document 1 proposes a structure in which a cover and a case are provided with a concave-convex positioning mechanism in order to keep the seal portion at a constant clearance, but in order to reliably engage the concave-convex positioning portion. Cannot be engaged unless there is a constant clearance between the respective concavities and convexities, and therefore variations occur during engagement.

  Therefore, there is still room for improvement in reducing the variation in assembly of the housing.

  In order to solve the above problems, the electronic control device of the present invention has a plurality of engaging claws that constitute a snap fit in one of the first and second casings, and the other one. The housing has a plurality of engaged bodies with which the engaging claws are engaged, and an engaging portion where the engaging claws and the engaged bodies are engaged is inclined.

  According to the present invention, since the engaging surface between the engaging claw and the engaged body has an inclined shape, the elastic force that the engaging claw expands and returns to the original state is applied to the first housing and the second case. Since the force can be applied in the direction in which both of the housings are attracted to each other, it is possible to reduce the assembly variation between the housings. As a result, variations in the heat radiating member can be reduced, so that an electronic control device having good heat radiating performance can be provided.

1 is a development view of a vehicle electronic control device according to a first embodiment of the present invention. 1 is a top view of a vehicle electronic control unit according to a first embodiment of the present invention. Sectional view of a vehicle electronic control unit according to a first embodiment of the present invention Sectional view of a vehicle electronic control unit according to a second embodiment of the present invention Sectional view of a vehicle electronic control unit according to a third embodiment of the present invention Top view and sectional view of a vehicle electronic control unit according to a fourth embodiment of the present invention

  Embodiments of the present invention will be described in detail below with reference to the drawings. The respective embodiments can be combined as long as no contradiction occurs.

[First Embodiment]
1 to 3 show a vehicle electronic control device according to a first embodiment of the present invention.

  In the present embodiment, an ECU (engine control unit) and an ATCU (automatic transmission control unit), which are vehicle electronic control devices mounted in the engine room, will be described in particular.

  The electronic control unit 1 in the present embodiment includes a connector 21 connected to a vehicle harness side, an electronic circuit board 4 on which an electronic component 41 is mounted, a first housing 2 and a second housing 2 for accommodating them. It is composed of a housing 3, an adhesive member 5, and a heat dissipation member 6.

  In this embodiment, the connector 21 is described as being integrally formed with the first housing 2, but the connector and the first housing may be separate bodies.

  The first housing 2 is made of a resin such as PBT (polybutylene terephthalate), PA (polyamide), PPS (polyphenylene sulfide), etc., and has a plurality of connector terminals that are metal whose main component is copper. There is.

  The connector terminal is a connector terminal for exchanging voltage and current inside and outside the electronic control unit.

  The second housing 3 has a heat dissipation plate 31 made of a metal whose main component is aluminum, iron, etc., and the heat dissipation plate includes PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), PA ( It is insert-molded with a molding resin 32 such as nylon.

  An electronic circuit board 4 is housed inside the first housing 2 and the second housing 3, and the gap between the first housing 2 and the second housing 3 is bonded by an adhesive member 5. Has been done.

  The adhesive member 5 is a waterproof seal member, and has a structure that prevents water from entering the inside of the electronic control unit.

  A plurality of electronic components 41 are mounted on the electronic circuit board 4, and the electronic circuit board is fixed to the first housing and connected to the connector terminals.

  Further, the electronic components that generate heat are radiated by the heat radiating member 6 to the heat radiating plate of the second casing.

  The electronic circuit board 4 is mainly composed of a base material in which glass cloth is impregnated with epoxy resin, and has a wiring layer made of copper in a multilayer structure.

  A plurality of electronic components 41 are connected to both surfaces of the electronic circuit board 4 by solder (not shown), and the wiring forms an electric circuit.

  The snap fit structure in this embodiment will be described.

  In the present embodiment, the first and second housings each have a plurality of snap fits 7 for engaging the housings around, and the engaging claws 71 of the snap fits 7 are the second The engaged body 72 is provided in the housing 3 in the first housing 2. The engaging claw 71 may be provided in the first housing 2 and the engaged body 72 may be provided in the second housing 3. The engaging portion 73 for engaging the engaging claw 71 and the engaged body 72 has an inclined shape.

  The parts constituting the snap fit 7 are made of an elastic material. For example, in the present embodiment, a resin such as PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), PA (nylon), etc. is proposed, but a metal such as iron or aluminum may be used.

  The snap-fit engagement claw formed of such an elastic material is opened outward at the time of engagement, and a force to return by an elastic force acts. In the present embodiment, the engaging force is applied in the direction in which the first casing and the second casing are attracted by engaging with the inclined portion of the engaged body before the engaging claw is completely returned. Therefore, the mating surfaces of the first casing and the second casing can be brought into a state of being completely in contact with each other. By doing so, in the normal snap-fit structure, there is play in the engaging portion, and variations in the play also occur in the mating surface of the housing, resulting in variations in assembly. By doing so, the variation can be suppressed.

  Further, since it is possible to reduce variations in the assembling of the casings, when the heat of the heat-generating components mounted in the first casing is radiated to the heat dissipation plate 31 of the second casing, it is applied between the respective casings. It is also possible to reduce variations in the thickness of the heat dissipating member 6.

Further, since the snap fits of the present invention are arranged at the positions facing each other on the outer periphery of the electronic control device, the elastic forces in the horizontal direction can be canceled each other.
The lateral displacement of the housing can be prevented.

[Second Embodiment]
FIG. 4 shows a vehicle electronic control unit according to a second embodiment of the present invention. The description of the same configuration as the first embodiment is omitted.

  The present embodiment has a structure in which the shape of the engaging portion on the engaging claw side is a curved surface. By adopting this structure, even if the operating amount of the engaging claws at the time of engagement changes due to dimensional variation of the product, etc., it can be surely brought into contact with the engaging part of the engaged body on any surface of the curved surface. Therefore, the engaging force can be transmitted more reliably.

  In other words, in contrast to the inclined surface having a constant inclination angle in the first embodiment, in the present embodiment, the spherical surface has a continuously changing inclination angle.

[Third Embodiment]
FIG. 5 shows a vehicle electronic control device according to a third embodiment of the present invention. The description of the same configuration as the first embodiment is omitted.

  The present embodiment has a structure in which the shape of the engaging portion on the engaged body side is a curved surface. With this structure, similarly to the second embodiment, the operating amount of the engaging claws at the time of engagement, even if it changes due to dimensional variation of the product, etc., reliably on some surface of the engaged body, Since it can be brought into contact with the engaging portion, the engaging force can be transmitted more reliably.

[Fourth Embodiment]
FIG. 6 shows a vehicle electronic control device according to a fourth embodiment of the present invention.
The fourth embodiment has a structure in which, of a plurality of snap fits around the electronic control device, both a snap fit having an inclined engaging portion of the present invention and a non-inclined snap fit are provided.

  In the present embodiment, even if the slanted snap fit should come off, the normal snap fit that is not slanted can surely hook the housing, so that a safer snap fit structure can be provided.

  In addition, in this embodiment, the snap fits of the present invention having an inclination are arranged at the four corners, and the other snap fits are the normal non-inclined snaps, so that the first housing and Since it is possible to more reliably contact the second housing, it is possible to reduce variations in assembly of the housings.

1. Vehicle electronic control unit
2. First housing
21. Connector
22. Connector terminal
3. Second housing
31. Heat dissipation plate
32. Mold resin
4. Electronic circuit board
41. Electronic components
5. Adhesive material
6. Heat dissipation member
7. Snap fit
71. Engaging claw
72. Engagement body
73. Engagement part

Claims (6)

In the electronic control device having the first and second casings,
Either one of the first or second housing has a plurality of engaging claws that form a snap fit,
The other casing has a plurality of engaged bodies with which the engaging claws are engaged,
The engaging portion with which the engaging claw and the engaged body are engaged has an inclined shape ,
The snap fit, the engagement with the first snap fit engagement portion is inclined, the electronic control device a second snap-fit that is not inclined that mixed.   The electronic control unit according to claim 1, wherein the engaging claw is made of an elastic member.   The electronic control device according to claim 1 or 2, wherein the plurality of engagement claws and the plurality of engaged members are respectively arranged at positions facing each other around the electronic control device.   The electronic control device according to claim 1, wherein an engaging surface of the engaging claw has a curved shape.   The electronic control device according to claim 1, wherein an engagement surface of the engaged body has a curved surface shape. The electronic control unit according to claim 1 , wherein the first snap fits are arranged at four corners of the electronic control unit.

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