JP2011031696A - Control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the adhesive strength of an adhesive on a control unit whose casing and cover are sealed therebetween by the adhesive, and to improve its heat radiation using the adhesive. <P>SOLUTION: A ridged protrusion 410 continuously extending along an end edge of the cover 400 is formed on an application face 402 for the adhesive BO on the cover 400. This improves the fitness of the adhesive BO applied when the cover 400 is attached to the casing 300 and further improves its impermeability to water owing to the increased adhesive strength. As the adhesive BO is pushed into the peripheral edge side of a printed board 200, in addition, the heat of the printed board 200 is transmitted to the casing 300 and the cover 400 via the adhesive BO, thereby improving the heat radiation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control unit configured by housing a printed circuit board on which electronic components are mounted in a case.

  Patent Document 1 discloses a control unit including a heat dissipation case, a metal substrate, an insulating substrate, and a cover. The control unit sequentially attaches the metal substrate and the insulating substrate to the heat dissipation cover with screws, and then attaches the cover. It is assembled by attaching to the heat dissipation case with screws.

JP 2003-011829 A

  By the way, in the control unit as described above, an adhesive may be applied between the case and the cover to form a waterproof structure. Conventionally, in order to secure an adhesive application area, it is provided on the heat dissipation case side. The adhesive was applied between the flat part and the flat part provided on the cover side, and the case and the cover were sealed with the adhesive.

  However, as described above, in the configuration in which the adhesive is applied to the flat portion and joined, bubbles are involved, and it is difficult to stably secure the adhesive strength, and the waterproofness is impaired. There was a case.

  Moreover, if heat of the electronic component mounted on the printed circuit board can be efficiently transferred to the case and the cover, high heat dissipation can be secured, but conventionally, the waterproof structure improves heat dissipation. It did not contribute enough.

  The present invention has been made in view of the above problems, and in a control unit that seals between a case and a cover using an adhesive, the adhesive strength by the adhesive is increased, and heat dissipation is achieved by the adhesive. The purpose is to be able to improve.

  Therefore, in the present invention, the edge portion of the printed circuit board is placed on and supported by the upper surface of the base portion formed on the inner periphery of the case, and the portion outside the portion on which the printed circuit board is placed on the upper surface of the base portion And the peripheral edge of the cover close to each other, and an adhesive is applied to the facing portion to seal the cover, and a convex portion that continues along the edge of the cover is further formed on the adhesive application surface of the cover. Formed.

  According to the above invention, when the cover is attached to the case, the familiarity of the adhesive is improved and the adhesive strength is increased, so that the waterproof property can be improved. As a result, the heat of the printed circuit board can be transmitted to the case cover through the adhesive, and the heat dissipation is improved.

It is a perspective view which shows embodiment of the control unit which concerns on this invention. It is a disassembled perspective view of the control unit in an embodiment. It is a top view which shows the case of embodiment. It is a top view which shows roughly the state which mounted the printed circuit board in the case in embodiment. It is sectional drawing of the control unit of embodiment. It is a partial expanded sectional view which shows the application part of the adhesive agent in the control unit of embodiment. It is a partial expanded sectional view which shows the application part of the adhesive agent in the control unit of embodiment. It is sectional drawing of the base-shaped part of the case in the control unit of embodiment. It is a partial expanded sectional view which shows the application part of the adhesive agent in the control unit of embodiment.

Embodiments of the present invention will be described below.
1 and 2 are views showing a basic configuration of a control unit according to the present invention, FIG. 1 is a perspective view of the control unit after assembly, and FIG. 2 is an exploded perspective view.

  The control unit 100 shown in the figure is disposed in, for example, an engine room of a vehicle and is used for control of an automatic transmission. The control unit 100 includes electronic components 201 such as a shunt resistor, a power supply IC, and a drive IC. The printed circuit board 200 is integrally provided with a connector 202, an aluminum die-cast case 300 that accommodates the printed circuit board 200, and an aluminum sheet metal cover 400 that covers the opening of the case 300.

  The case 300 is formed in a bottomed box shape, and on both side surfaces along the longitudinal direction, there are integrally attached portions 302 formed with through holes 301 for inserting fixing bolts to the attachment positions. Protrusions are formed.

  In addition, a concave connector housing portion 303 for housing the connector 202 of the printed circuit board 200 is formed at one end in the longitudinal direction of the case 300, and the bottom outer surface 304 is interposed in a breathing hole. A mounting portion 306 of a filter (water repellent filter) 305 to be made, a heat radiation fin 307, and the like are integrally formed.

  On the other hand, the cover 400 is formed in a rectangular dish shape whose central portion is raised outward with respect to the peripheral edge, and through holes 401 for inserting male screws for fixing to the case 300 are formed in the four corners. Is done.

  The cover 400 is fitted inside the opening end of the case 300, and the male screw inserted through the through hole 401 is aligned with the through hole 401 and fastened to the female screw portion 308 provided in the case 300. As a result, the cover 400 is fixed to the case 300.

  Further, when the cover 400 is fixed to the case 300, the edge portion of the printed circuit board 200 is sandwiched between the case 300 and the cover 400, so that the space formed by the case 300 and the cover 400 is within the space. The printed circuit board 200 is fixed.

FIG. 3 shows an inner shape of the case 300 to which the printed circuit board 200 is fixed.
A base portion 311 that is one step lower than the opening edge 310 of the case 300 is formed along the inner periphery of the opening edge 310 except for a portion where the connector housing portion 303 is formed.

  The outer shape of the printed circuit board 200 is larger than the region surrounded by the rising surface 311 a of the base portion 311 and smaller than the inner periphery of the opening edge 310, and is formed on the base portion 311. The printed circuit board 200 is accommodated in the case 300 by placing the peripheral edge.

  Wall-shaped portions 312 for positioning the printed circuit board 200 are respectively formed on the upper surface portion of the table-shaped portion 311 corresponding to the four corners of the case 300, and as shown in FIG. When the printed circuit board 200 is placed in an area surrounded by the four corners 312, movement in a direction parallel to the end face of the printed circuit board 200 is restricted, and the printed circuit board 200 is positioned with respect to the case 300 (the table-shaped portion 311). .

The rising height of the wall-shaped portion 312 from the upper surface of the platform-shaped portion 311 is set to be equal to or less than the thickness of the printed circuit board 200.
FIG. 5 is a cross-sectional view of the control unit 100 after assembling. As shown in FIG. 5, when the printed board 200 is placed on the platform portion 311, the printed board 200 is located near the middle in the depth direction of the case 300. Is supported.

  As shown in FIG. 5, the cover 400 has a frame-like flange portion 402 provided so as to face the base portion 311, and rises from the inner peripheral edge of the flange portion 402 to a predetermined height H to form an electronic component. The through hole 401 is formed at the four corners of the flange portion 402.

  When the printed circuit board 200 is placed on the upper surface of the table-like part 311 positioned by the wall-like part 312 and the cover 400 is put on, the outer peripheral edge of the flange part 402 of the cover 400 is the opening edge 310 of the case 300. The cover 400 is fixed to the case 300 with screws at a position where it is loosely fitted on the inner periphery and the flange portion 402 contacts the printed circuit board 200.

  At this time, since the printed circuit board 200 is sandwiched between the base portion 311 and the flange portion 402, the printed circuit board 200 is fixed to the case 300 by tightening and fixing the cover 400 to the case 300. It is sandwiched between and fixed.

  Here, the part where the base part 311 and the flange part 402 are opposed to each other with the gap S interposed therebetween without passing through the printed board 200, in other words, outside the part on which the printed board 200 of the base part 311 is placed. Then, an adhesive BO is applied to a portion where the base portion 311 and the flange portion 402 are closely opposed to each other, the gap S is sealed with the adhesive BO, and the gap between the cover 400 and the case 300 is Water is prevented from entering the space in which the printed circuit board 200 is accommodated.

  Note that the type of the adhesive BO may be appropriately selected in consideration of the material of the case 300 and the cover 400, the sealing property, the use environment, and the like, and the contained material and the curing characteristics are not limited. Since it is the structure which aims at the heat dissipation through agent BO, it is preferable to use what has high heat conductivity (heat transfer adhesive: the adhesive agent which added the heat transfer filler).

In order to improve the performance of the waterproof structure using the adhesive BO, a mountain-shaped convex portion 410 and an L-shaped bent portion 411 are formed on the cover 400.
As shown in FIG. 6, the mountain-shaped convex portion 410 is an application surface of the adhesive BO that faces the platform portion 311 of the flange portion 402, and does not contact the printed circuit board 200. It is continuously formed along an edge (a release end inner peripheral surface 315 described later), and is formed in a mountain shape that protrudes toward the platform portion 311 in the cross section in the width direction of the flange portion 402.

  Note that the cross-sectional shape of the mountain-shaped convex portion 410 is easy to spread the adhesive BO, and preferably has a shape with little air entrainment, and has a sharp tip, a flat tip, Further, the inclined surface may be formed flat, or the inclined surface may be formed in an arc shape.

  In addition, as shown in FIGS. 2, 5 and 6, the L-shaped bent portion 411 has the edge of the cover 400 outward on each of the three sides except for one side where the connector 202 of the cover 400 is provided. The L-shaped bent portion 411 is formed in parallel with the open end inner peripheral surface 315 rising from the base portion 311 of the case 300 toward the opening edge 310 via the gap SS. And the front-end | tip 411a of the L-shaped bending part 411 is set so that it may become lower than the opening edge 310. FIG.

Here, the operation and effect of the mountain-shaped convex portion 410 and the L-shaped bent portion 411 will be described.
The adhesive BO is applied on the base part 311 outside the printed board 200 (wall part 312) in a state where the printed board 200 is placed on the base part 311, and then the cover 400 is applied to the case 300. Installation is performed.

  In the operation of attaching the cover 400 to the case 300, as the cover 400 approaches the case 300, the mountain-shaped convex portion 410 of the flange portion 402 crushes the adhesive BO applied on the base portion 311, and further It acts to push the adhesive BO toward both sides in the direction in which the mountain-shaped convex portions 410 are continuous.

  Therefore, even if air bubbles are mixed in the adhesive BO at the time of applying the adhesive BO, the crushing operation of the mountain-shaped convex portion 410 acts to push out the air bubbles toward both sides, and the air bubbles remain. It can suppress adhering. This eliminates as much as possible bubbles (air layers) in the bonding portion (the hatched portion of the adhesive BO in FIG. 6) between the printed circuit board 200, the cover 400, and the case 300, and the electronic component mounted on the printed circuit board 200. The heat of 201 can be dissipated through the adhesive BO that is closely packed without using bubbles, and the heat dissipation efficiency is improved.

  Thus, by providing the convex portion 410 on the flange portion 402, the familiarity of the adhesive BO can be improved, and the sealing performance by the adhesive BO between the case 300 and the cover 400 can be reduced. Waterproof performance and heat dissipation efficiency increase.

  Further, the adhesive BO pushed out toward the periphery of the case 300 by the mountain-shaped convex portion 410 enters the gap SS between the L-shaped bent portion 411 and the open end inner peripheral surface 315, and the L-shaped bent portion. The space between 411 and the open end inner peripheral surface 315 is also sealed with the adhesive BO.

  For this reason, the space between the L-shaped bent portion 411 and the inner peripheral surface 315 of the open end is sealed with the adhesive BO and continuous with the portion where the base portion 311 and the flange portion 402 are close to each other and facing each other. The stopping distance (minimum distance from the outside to the accommodation space of the printed circuit board 200 via the part where the adhesive BO is applied) becomes longer, and this also causes the sealing performance between the case 300 and the cover 400 by the adhesive BO. Pulling can improve waterproof performance.

  Further, if the L-shaped bent portion 411 is provided on the cover 400 made of sheet metal, the rigidity of the portion where the L-shaped bent portion 411 is provided increases, and in particular, along the longitudinal direction of the cover 400 where the bending moment increases. If the L-shaped bent portions 411 are formed on both sides, the rigidity in the longitudinal direction increases, and the necessary and sufficient rigidity can be provided without increasing the plate thickness. However, the L-shaped bent portion 411 is not essential in terms of the heat dissipation structure, and a heat dissipation effect is exhibited even with a simple cut shape or the like.

  Further, the adhesive BO is pushed into the printed circuit board 200 side by the crushing of the adhesive BO by the mountain-shaped convex portion 410, and the gap between the flange portion 402 of the cover 400 and the printed circuit board 200, the printed circuit board 200, and the case. It will also enter into the gap with the 300-like table portion 311.

  The printed circuit board 200 is sandwiched between the flange portion 402 of the cover 400 and the base portion 311 of the case 300, thereby closely contacting the flange portion 402 and the base portion 311. Heat is transmitted to the cover 400 and the case 300.

  Here, there is a case where a gap is generated between the flange portion 402 and the base portion 311 due to deformation / deflection of the printed circuit board 200, but the adhesive BO is inclined on the printed circuit board 200 side of the mountain-shaped convex portion 410. By pushing into the printed circuit board 200 side, the gap can be filled with the adhesive BO.

  Accordingly, the flange portion 402 of the cover 400 and the printed board 200 are in close contact with each other through the adhesive BO, and the printed board 200 and the base portion 311 of the case 300 are in close contact with each other through the adhesive BO. 200, heat transfer to the case 300 and the cover 400 is improved, and the heat of the electronic component 201 mounted on the printed circuit board 200 can be efficiently radiated through the case 300 and the cover 400.

  When the printed board 200 is grounded to the case 300, if the corner portion of the printed board 200 is placed on the platform portion 311 inside the wall-like part 312, it is pushed out by the mountain-shaped convex part 410. The flow of the adhesive BO to be blocked is blocked by the wall-shaped portion 312, so that the adhesive BO can be prevented from entering the grounding portion, and the grounding performance can be ensured. In the present embodiment, the corner portion of the printed circuit board 200 is the grounding portion. However, the present invention is not limited to this, and the same effect can be obtained in other portions.

  Further, the corner portion of the printed circuit board 200 is a region sandwiched between the two sides of the flange portion 402 of the cover 400 and the two sides of the base portion 311 of the case 300, and the heat dissipation performance is higher than other regions. Therefore, if the electronic component 201 is not provided with a dedicated heat dissipating means and a component with a large amount of generated heat is arranged at the corner of the printed circuit board 200, the entire printed circuit board 200 can be radiated efficiently.

  Further, as shown in FIG. 7, a plurality of through holes 210 for heat dissipation are formed in the peripheral portion of the printed circuit board 200 that is sandwiched between the flange portion 402 of the cover 400 and the base portion 311 of the case 300. If the through hole 210 is filled with a heat conductive material, if there is a temperature difference between the front and back of the printed circuit board 200, heat is conducted through the through hole 210, and the temperature difference between the front and back of the printed circuit board 200 is reduced. Suppression can be achieved. When the printed circuit board 200 is a multilayer, the heat transferred to the inner layer can be radiated to the cover 400 and the case 300 through the through hole 210.

Note that solder, grease, adhesive BO, or the like can be used as the heat conductive material to fill the through hole 210.
Further, in order to more positively fill the adhesive BO into the gap between the printed circuit board 200 and the base part 311 of the case 300, a concave part can be provided in the base part 311. The end portion of the printed circuit board 200 is an area where electronic components cannot be mounted, and can be effectively used as a heat dissipation area.

  FIG. 8 is a cross-sectional view of a portion of the base portion 311 on which the printed circuit board 200 is placed in parallel with the longitudinal direction of the case 300. At both ends of the longitudinal direction of the case 300, the base portion 311 is a printed circuit board. 200 is formed at a reference height that supports 200, but by decreasing the height of the base portion 311 as it approaches the central portion from both ends, a concave portion 321 that is recessed in an arc shape that increases in depth as it approaches the central portion from both ends is formed. It is formed.

A support column 332 that supports the printed circuit board 200 is formed to protrude from the bottom of the deepest portion at the center of the recess 321.
The height of the upper surface of the support column 332 is set to be the same as or slightly lower than the height of the base portion 311 at both ends in the longitudinal direction of the case 300, and the longitudinal center of the printed circuit board 200 is set to the case 300 side. The column 332 supports the printed circuit board 200 so that a large deflection is not generated in the printed circuit board 200 when a force (force in the direction of arrow α in FIG. 8) is applied to the printed circuit board 200.

  FIG. 9 is a cross-sectional view taken along the line AA in FIG. 8, and the width W of the concave portion 321 exceeds the end surface of the printed circuit board 200 from the rising surface 311a of the base portion 311. The width is set to be equal to or larger than the width at which 311 and the printed circuit board 200 face each other.

  If the concave portion 321 is formed as described above, the adhesive BO is crushed by the mountain-shaped convex portion 410 when the cover 400 is attached and formed by the concave portion 321 when pressed toward the printed circuit board 200 side. Enters the gap between the printed circuit board 200 and the table portion 311.

  That is, when the concave portion 321 is not provided, the adhesive BO enters a gap that is indefinitely generated due to deformation or bending of the printed circuit board 200. However, the concave portion 321 is formed as described above to form the printed circuit board 200. If a predetermined gap is formed between the base portion 311 and the adhesive BO, the adhesive BO can be kept in a constant space between the printed board 200 and the base portion 311. A layer of the adhesive BO can be formed between the base portion 311.

  As a result, the heat transferred from the printed circuit board 200 to the adhesive BO can be directly dissipated from the layer of the adhesive BO, and further, the control unit can transfer heat from the adhesive BO to the case 300. The heat dissipation performance of 100 can be further improved.

  In particular, as shown in FIG. 9, when the concave portion 321 and the through hole 210 are combined, the heat on the surface of the printed circuit board 200 on the cover 400 side is transferred to the printed circuit board 200 and the table-shaped portion 311 via the through hole 210. Between the adhesive BO layer and the case 300, thereby suppressing the occurrence of a temperature difference between the front and back of the printed circuit board 200, and the printed circuit board. The heat of 200 can be radiated more efficiently.

It should be noted that the concave portion 321 is not limited to a shape that is recessed in an arc shape, and the same action and effect can be obtained in a trapezoidal shape, a triangular shape, or the like, and a plurality of concave portions 321 may be formed side by side.
In addition, the depth of the recess 321 may be appropriately set according to the shape of the recess 321, the cover 400, the case 300, and the like, the thermal conductivity, the sealing property, the viscosity, and the like of the adhesive BO.

  DESCRIPTION OF SYMBOLS 100 ... Control unit, 200 ... Printed circuit board, 210 ... Through-hole, 300 ... Case, 311 ... Base part, 321 ... Recessed part, 332 ... Post, 400 ... Cover, 402 ... Flange part, 410 ... Mountain-like convex part, 411 ... L-shaped bent part, BO ... Adhesive

Claims (4)

A control unit comprising a printed circuit board on which electronic components are mounted, a case for housing the printed circuit board, and a cover for covering an opening of the case,
On the upper surface of the base portion formed on the inner periphery of the case, the edge portion of the printed circuit board is placed and supported, and the portion of the upper surface of the base portion that is outside the portion on which the printed circuit board is mounted; Protruding portions that are arranged close to the peripheral edge of the cover, and are sealed by applying an adhesive to the facing portion, and continuous along the edge of the cover on the adhesive application surface of the cover A control unit characterized by being formed.   The control unit according to claim 1, wherein an outer edge of a surface of the cover to which the adhesive is applied is bent in an L shape.   The control unit according to claim 1 or 2, wherein a plurality of through holes for heat dissipation are formed on a peripheral edge of the printed circuit board.   The control unit according to any one of claims 1 to 3, wherein a concave portion that forms a gap between the top surface of the base portion and the printed board is formed on the top surface of the base portion.

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