JP4983756B2 - Electronic circuit equipment - Google Patents

Description

  The present invention relates to an electronic circuit device, and more particularly to an electronic circuit device in which a circuit board is accommodated in a case having a bottom portion and a side wall portion and opened upward, and a cover for closing the opening of the case is attached.

Conventionally, in this type of electronic circuit device, a groove is formed over the entire periphery of the opening edge of the case that accommodates the circuit board, and the entire periphery of the groove is fitted with a clearance in the depth direction and the width direction. There has been proposed a method in which a protrusion is formed on a cover and the cover is attached to the case in a state where an adhesive is injected into the groove (see, for example, Patent Document 1). In this device, the adhesive is stretched so as to enter the gap between the outer peripheral surface of the protrusion and the inner wall surface of the groove, and the groove and the protrusion are bonded together to maintain the airtightness in the case and protect the circuit board. It is said.
JP 2003-229516 A

  As described above, in an electronic circuit device, a cover needs to be attached to the case with sufficient airtightness to protect the circuit board. However, depending on the use environment, the case and the cover may be repeatedly expanded and contracted to adhere to the bonding surface. May deteriorate. In particular, when materials having different linear expansion coefficients are used for the case and the cover, the difference between the amount of deformation of the case and the amount of deformation of the cover during thermal expansion and contraction becomes large, and the deterioration of the adhesive surface becomes remarkable. Then, when the adhesion surface deteriorates, moisture enters the deteriorated portion and corrosion progresses, and the strength of the adhesion surface in the corroded portion further decreases. In addition, in electronic circuit devices installed in vehicles with harsh usage environments, the deterioration of the adhesive surface becomes more noticeable due to severe temperature changes, and water droplets scattered during traveling and steam in the engine room can be attached to the adhesive part. The problem has become apparent because moisture tends to accumulate and the corrosion progresses quickly.

  The main purpose of the electronic circuit device of the present invention is to more reliably protect the circuit board accommodated in the case.

  The electronic circuit device of the present invention employs the following means in order to achieve the main object described above.

The electronic circuit device of the present invention is
An electronic circuit device in which a circuit board is accommodated in a case having a bottom part and a side wall part and the upper part is opened and a cover for closing the opening of the case is attached,
In the case, a recess is formed over the entire periphery on the upper end surface of the side wall,
In the cover, a convex portion that fits over the entire circumference of the concave portion and a flange that covers at least a part of the outer peripheral surface of the side wall portion are formed,
When the cover is attached to the case by fitting the convex portion into the concave portion using an adhesive, the inner peripheral surface from the concave portion of the concave portion and the inner peripheral surface from the protrusion of the convex portion The recess and / or the protrusion is arranged on the inner periphery so that one of the interval between the gap between the gap and the gap on the outer circumference side of the recess and the gap on the outer circumference side of the projection on the projection is larger than the other. It is characterized in that it is formed in steps with different heights on the side surface and the outer peripheral surface.

  In the electronic circuit device according to the present invention, when the cover is attached to the case by fitting the convex portion to the concave portion formed over the entire circumference on the upper end surface of the side wall portion of the case using the adhesive, the concave portion of the concave portion Also, one of the distance between the inner peripheral surface and the inner peripheral surface than the convex protrusion and the interval between the outer peripheral surface and the convex outer protrusion from the concave recess is one of the other The concave portion and / or the convex portion are formed in steps having different heights between the inner peripheral surface and the outer peripheral surface. As a result, if the adhesive is filled between the inner peripheral surfaces and the outer peripheral surfaces, it can be elastically deformed by the thickness of the adhesive portion on the side with the larger interval, and the thermal expansion and contraction of the case and cover The adhesive surface can be prevented from being peeled off following the deformation of the time. In addition, since the adhesive part is not exposed when the collar part covers a part of the side wall part, it is possible to prevent moisture that causes corrosion from scattering and adhering or dripping from the cover and collecting on the adhesive part. it can. As a result, it is possible to more reliably protect the circuit board accommodated in the case while suppressing the deterioration of the adhesive surface and suppressing the progress of corrosion.

  In such an electronic circuit device of the present invention, the smaller one of the distance between the inner peripheral surfaces and the distance between the outer peripheral surfaces may be substantially zero. By doing so, it is possible to position the cover in the height direction with respect to the case by reliably bonding either the inner peripheral surfaces or the outer peripheral surfaces.

  In the electronic circuit device of the present invention, the interval between the outer peripheral surfaces may be larger than the interval between the inner peripheral surfaces. Here, the influence of deformation of the case and cover due to thermal expansion and contraction tends to be larger on the outer peripheral side with less restraint, but by increasing the adhesive thickness of the adhesive part on the outer peripheral side, It can respond more appropriately.

  Furthermore, in the electronic circuit device of the present invention, the recess is formed so that the inner peripheral surface and the outer peripheral surface are substantially flush with each other than the depression, and the convex portion is formed on the inner periphery of the protrusion. It can also be formed in the level | step difference shape from which the height of the surface of a side differs from the surface of an outer peripheral side. In this way, the bonding operation can be performed smoothly.

  In the electronic circuit device of the present invention, the cover may be formed such that the ridge covers the entire outer peripheral surface of the side wall portion. Here, corrosion often starts from an exposed portion of the outer peripheral surface of the case or cover that is exposed to the outside. Since the distance from the bonded portion, that is, the distance from the starting point of corrosion to the bonded portion can be increased, the progress of corrosion can be further suppressed.

  In the electronic circuit device of the present invention, the cover may be manufactured from a material having a linear expansion coefficient different from that of the case. When the linear expansion coefficient is different, the difference between the deformation amount of the case and the deformation amount of the cover at the time of thermal expansion / contraction is increased, and the adhesive surface is easily peeled off. Therefore, it is significant to apply the present invention. In the electronic circuit device of this aspect of the present invention, the case may be a metal case, and the cover may be a resin cover.

  Furthermore, in the electronic circuit device of the present invention, the circuit board may be an electronic control unit for shift control attached to the automatic transmission. In this aspect of the electronic circuit device of the present invention, the automatic transmission is an in-vehicle transmission, and the case is provided with a shift position detection unit that detects a shift position that is displaced according to a driver's operation. It is also possible to form the through hole into which the shift position detecting portion is inserted and fitted in the cover. An electronic circuit device mounted on a vehicle is particularly harsh in its usage environment, and the deterioration of the adhesion surface and the progress of corrosion become significant, so that it is significant to apply the present invention.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is an external view showing the external appearance of an automatic transmission 10, FIG. 2 is a block diagram showing an outline of the configuration of an electronic circuit device 20 as an embodiment of the present invention, and FIG. FIG. 4 is an external view showing an external appearance of a case 40 of the electronic circuit device 20, FIG. 4 is an AA partial sectional view showing an AA partial cross section of the case 40 of FIG. 3, and FIG. FIG. 6 is an external view showing an external appearance of the cover 60 of the circuit device 20, and FIG. 6 is a BB cross-sectional view showing a BB cross section of the cover 60 of FIG. The electronic circuit device 20 of the embodiment is configured as an AT electronic control unit (ATECU) in an automobile in which an automatic transmission (AT) 10 is mounted in an engine room together with an engine (not shown), as shown in FIG. The automatic transmission 10 is attached to a transmission case 12. In this electronic circuit device 20, a gear position is set based on the vehicle speed, throttle opening, and shift position, and an actuator (incorporated in the hydraulic circuit) that turns on and off the clutch and brake mounted on the automatic transmission 10 based on the set gear position. As shown in FIG. 2, a control board 30 on which a plurality of electronic elements are mounted, a shift position sensor 22 for detecting the operation position of the shift lever, A connector 24 and the like for communicably connecting to an engine electronic control unit for controlling the engine are provided. After these are fixed to the case 40, the cover 60 is attached to the case 40. Although not shown, the shift position sensor 22 includes a permanent magnet attached to the rotor and a magnetic sensor (for example, a hall element) attached to the stator and detecting a magnetic field of the permanent magnet. As shown in FIG. 1, a part thereof protrudes upward.

  The control board 30 is configured as a resin board such as a glass epoxy board, for example, and is fixed to the case 40 with a plurality of bolts 28 as shown in FIG. The electronic elements mounted on the control board 30 include a power supply IC 32 for supplying power to each part, a solenoid drive circuit 34 for driving a linear solenoid valve in the hydraulic circuit, and a microcomputer (microcomputer) for controlling the entire apparatus. 36).

  The case 40 is manufactured from a metal having high thermal conductivity. In this embodiment, the case 40 is manufactured by an aluminum die casting method using aluminum as a material. The linear expansion coefficient of aluminum is about 21 to 23 × 10 / ° C. As shown in FIGS. 3 and 4, the case 40 includes a bottom portion 42 and a side wall portion 52 that rises substantially vertically from the outer peripheral portion of the bottom portion 42 and forms an opening inside. The bottom portion 42 is formed with a plurality of bolt holes 44 into which the bolts 28 are fastened, a plurality of convex pedestals 46 integrated with the bottom portion 42, and a plurality of radiating fins 48 protruding from the back surface. Since the back surface side of the control board 30 is bonded and fixed to the pedestal 46 using, for example, a silicone-based adhesive having excellent thermal conductivity, the heat generated by the electronic elements mounted on the control board 30 is generated from the control board 30. The heat is radiated from the radiating fin 48 to the outside through the pedestal 46 and the bottom 42. In the side wall portion 52, a recess 56 is formed over the entire circumference at the approximate center in the cross-sectional direction of the upper end surface 54, and a plurality of claw portions 58 are formed on the outer peripheral surface. By this recess 56, the upper end surface 54 is divided into an inner peripheral upper end surface 54a and an outer peripheral upper end surface 54b on the inner peripheral side with respect to the depression of the concave portion 56, and the inner peripheral upper end surface 54a and the outer peripheral side upper side are separated. It is formed so as to be flush with the end face 54b. Further, the claw portion 58 is formed in a substantially right triangle shape in cross-section at the tip portion so that a claw hook portion 69 of the cover 60 described later can be hung.

  The cover 60 is made of a highly corrosion-resistant resin. In this embodiment, the cover 60 is made of PBT-GF30 (polybutylene terephthalate containing glass fiber) resin (hereinafter simply referred to as PBT resin). The linear expansion coefficient of the PBT resin is about 30 to 130 × 10 / ° C., which is different from the linear expansion coefficient of aluminum that is the material of the case 40. As shown in FIGS. 5 and 6, the cover 60 includes a cover main body 62 having substantially the same shape as the case 40, and a convex portion formed by protruding from the back surface of the cover main body 62 at a position corresponding to the concave portion 56 of the case 40. 66, a flange 68 formed in a wall shape substantially the same height as the side wall 52 of the case 40 along the outer periphery of the cover main body 62, and a nail of the case 40 formed so as to partially cut out the flange 68. A plurality of claw-hanging portions 69 respectively hung on the portion 58, a raised portion 72 formed by partially protruding from the upper surface of the cover main body 62, a portion corresponding to the mounting portion of the shift position sensor 22 of the case 40, and a raised portion A through hole 74 formed in the portion 72 is formed. The convex portion 66 is formed so that the inner peripheral shoulder surface 66a on the inner peripheral side of both the shoulder surfaces 66a and 66b is higher than the outer peripheral shoulder surface 66b on the outer peripheral side (extends downward in the figure). Further, the height from the inner peripheral shoulder surface 66 a to the tip of the protrusion of the convex portion 66 is formed to be lower than the depth of the recess of the concave portion 56. FIG. 7 shows a cross-sectional view of the state where the convex portion 66 is fitted in the concave portion 56. As described above, the inner peripheral side upper end surface 54a and the outer peripheral side upper end surface 54b are formed to be flush with each other, and the shoulder surfaces 66a, 66b are formed to have different heights. A gap is formed between the outer peripheral upper end surface 54b and the outer peripheral shoulder surface 66b in a state where the peripheral upper end surface 54a and the inner peripheral shoulder surface 66a are in contact with each other without a gap.

  The attachment of the cover 60 to the case 40 thus configured will be described. 8 is an external view showing the external appearance of the electronic circuit device 20 in which the cover 60 is attached to the case 40, and FIG. 9 is a partial CC cross section showing the CC partial cross section of the electronic circuit device 20 of FIG. FIG. As shown in the drawing, the upper end surface 54 and the concave portion 56 of the side wall portion 52 of the case 40 are bonded to the convex portion 66 and the shoulder surfaces 66a and 66b of the cover 60 using an adhesive, and a plurality of claw hook portions 69 are formed. The cover 60 is attached to the case 40 by being hooked on the corresponding claw portions 58. Further, the shift position sensor 22 is in a state of penetrating through a through hole 74 formed in the raised portion 72. In this embodiment, a silicone-based adhesive having low hardness after curing and elasticity is used as an adhesive, and a necessary amount of adhesive is applied in advance to the upper end surface 54 of the side wall 52 or injected into the recess 56. After that, the cover 60 is attached. As described above, since a gap is formed between the outer peripheral side upper end surface 54b and the outer peripheral side shoulder surface 66b, as shown in FIG. 9, the inner peripheral side is thinned with the adhesive, whereas the outer peripheral side is The adhesive has a thickness. For this reason, the height of the cover 60 relative to the case 40 can be aligned with the bonding surface on the inner peripheral side, and the cover 60 can be securely bonded, and the gap between the shift position sensor 22 and the through hole 74 due to the lift of the cover 60. Can be prevented. Further, since the elastic adhesive has a thickness, it can be elastically deformed by giving elasticity to the bonded portion on the outer peripheral side. Further, since the flange portion 68 is formed at substantially the same height as the side wall portion 52 of the case 40 and covers substantially the entire outer peripheral surface of the side wall portion 52, the adhesive portion is prevented from being exposed and the case 40 and the cover 60 are not exposed. It is possible to increase the distance from the exposed portion that becomes the starting point of corrosion to the bonded portion. Here, as in the present embodiment, the electronic circuit device 20 mounted on the transmission case 12 of the automobile frequently fluctuates while the case 40 and the cover 60 repeat thermal expansion and contraction due to severe temperature changes in the engine room. It is placed in a harsh environment where moisture is likely to accumulate in the bonded area due to water droplets and steam in the engine room. In particular, at the time of thermal expansion and contraction, the deformation direction and the deformation amount differ depending on the linear expansion coefficient and the shape of the case 40 and the cover 60. For example, the cover 40 is deformed so as to warp upward as indicated by an arrow in FIG. A force that peels off the adhesive surface may act. Note that the influence of deformation of the case and the cover due to thermal expansion and contraction tends to be greater on the outer peripheral side with less restraint, and accordingly, the force that peels off the adhesive surface becomes larger on the outer peripheral side. When the adhesion surface deteriorates due to the action of such a force, a vicious cycle occurs in which corrosion proceeds to the inside due to moisture that has entered the deteriorated portion and the strength of the adhesion surface further decreases. On the other hand, in the present embodiment, the adhesion portion on the outer peripheral side is elastically deformed to follow the deformation of the case 40 and the cover 60, so that the adhesion surface can be prevented from being peeled off. In addition, the adhesive portion is prevented from being exposed by the collar portion 68 to prevent water droplets scattered or water dripping from above the cover 60 from accumulating on the adhesive portion and to increase the distance from the starting point of corrosion to the adhesive portion. Thus, the progress of corrosion can be suppressed. Therefore, it is possible to more reliably protect the control substrate 30 accommodated in the case 40 while suppressing the deterioration of the adhesion surface and suppressing the progress of corrosion.

  According to the electronic circuit device 20 of the embodiment described above, when the cover 60 is attached to the case 40 by bonding, the inner peripheral shoulder surface 66a of the convex portion 66 of the cover 60 and the inner periphery of the side wall portion 52 of the case 40 are used. The adhesive is bonded to the side upper end surface 54a in a state where the adhesive is thinly stretched, and the adhesive is formed in a gap formed between the outer peripheral side shoulder surface 66b of the convex portion 66 and the outer peripheral side upper end surface 54b of the side wall portion 52. Since the side wall 52 is covered so that the flange portion 68 of the cover 60 is not exposed, and the height of the cover 60 is adjusted with respect to the case 40 by the inner peripheral adhesive surface. In addition, it is possible to securely bond and prevent the bonding portion on the outer peripheral side from elastically deforming and following the deformation of the case 40 and the cover 60 during thermal expansion and contraction, and preventing the bonding surface from being peeled off. Can and , It is possible to prevent water from accumulating in the adhered portion. As a result, it is possible to more reliably protect the control board 30 accommodated in the case 40 by suppressing the deterioration of the adhesive surface and suppressing the progress of corrosion. Moreover, since the collar part 68 covers substantially the entire outer peripheral surface of the side wall part 52 of the case 40, the progress of the corrosion is further suppressed by increasing the distance from the exposed part of the case 40 and the cover 60 which is the starting point of corrosion to the bonded part. can do.

  In the electronic circuit device 20 of the embodiment, both the upper end surfaces 54a and 54b of the side wall portion 52 of the case 40 are formed to be flush with each other, and both the shoulder surfaces 66a and 66b of the convex portion 66 of the cover 60 are raised. However, the present invention is not limited to this, and the upper end surfaces 54a and 54b of the side wall 52 are formed in a step so as to have different heights, and both shoulder surfaces 66a and 66b of the convex portion 66 are formed. The upper end surfaces 54a and 54b of the side wall 52 and the shoulder surfaces 66a and 66b of the convex portion 66 may be stepped so as to have different heights. It may be formed. Further, although the gap is formed on the outer peripheral side, the gap may be formed on the inner peripheral side. However, it is preferable to form a gap on the outer peripheral side as in this embodiment in order to prevent peeling of the outer peripheral adhesive surface that becomes the starting point of corrosion.

  In the electronic circuit device 20 of the embodiment, the convex portion 66 is formed so that the height of the projection is lower than the depth of the recess of the concave portion 56, and the inner peripheral side upper end surface 54a and the inner peripheral side shoulder surface 66a are in contact with no gap. In this state, a gap is formed between the outer peripheral side upper end surface 54b and the outer peripheral side shoulder surface 66b. However, the present invention is not limited to this, and the height of the projection 66 is greater than the depth of the depression of the recess 56. A gap is formed between the inner peripheral side upper end surface 54a and the inner peripheral side shoulder surface 66a when the tip of the protrusion of the convex portion 66 abuts against the bottom surface of the recess of the concave portion 56, and the outer peripheral side. A gap having a size different from that of the inner peripheral side may be formed between the upper end surface 54b and the outer peripheral side shoulder surface 66b.

  In the electronic circuit device 20 of the embodiment, the flange portion 68 of the cover 60 is formed so as to be substantially the same as the height of the side wall portion 52 of the case 40. However, the present invention is not limited thereto, and at least a part of the side wall portion 52 is formed. As long as it covers, it may be formed at any height. However, it is preferable to form it as high as possible.

  In the electronic circuit device 20 of the embodiment, the concave portion 56 is formed at the approximate center of the upper end surface 54 of the side wall portion 52. However, the present invention is not limited to this, and the concave portion 56 can be bonded to the inner peripheral side and the outer peripheral side. If the surface can be formed, it may be formed at a position biased to either side.

  In the electronic circuit device 20 according to the embodiment, the cover 60 is not only bonded when attached to the case 40 but also the nail hook portion 69 is hung on the nail portion 58. The cover 60 may be fastened to the case 40.

  In the electronic circuit device 20 of the embodiment, the case 40 is manufactured from aluminum. However, the case 40 is not limited to aluminum, and any metal that can function as the case 40 may be used. The cover 60 is made of PBT resin. However, the cover 60 is not limited to PBT resin, and any resin that can function as the cover 60 may be used. Furthermore, the present invention is not limited to the combination of metal and resin, and the case 40 and the cover 60 may be a combination of the same material.

  In the embodiment, the electronic circuit device of the present invention is applied to the electronic control unit that controls the automatic transmission 10 mounted on the automobile. However, the electronic circuit unit is installed in an automatic transmission mounted on a vehicle other than the automobile. It may be applied, or may be applied to an electronic control unit that controls other devices.

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the control board 30 corresponds to a “circuit board”. The shift position sensor 22 corresponds to a “shift position detection mechanism”. The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. It is an example for specifically explaining the best mode for doing so, and does not limit the elements of the invention described in the column of means for solving the problem. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

  The present invention can be used in the manufacturing industry of electronic circuit devices.

1 is an external view showing an external appearance of an automatic transmission 10. FIG. It is a block diagram which shows the outline of a structure of the electronic circuit apparatus 20 as one Example of this invention. 2 is an external view showing an external appearance of a case 40 of the electronic circuit device 20. FIG. FIG. 4 is an AA partial cross-sectional view showing a cross-section AA of the case 40 of FIG. 3. 2 is an external view showing an external appearance of a cover 60 of the electronic circuit device 20. FIG. It is BB sectional drawing which shows the BB cross section of the cover 60 of FIG. 6 is a cross-sectional view showing a state in which a convex portion 66 is fitted in a concave portion 56. FIG. 2 is an external view showing an external appearance of an electronic circuit device 20 in which a cover 60 is attached to a case 40. FIG. FIG. 10 is a CC partial cross-sectional view showing a CC partial cross-section of the electronic circuit device 20 of FIG. 8.

Explanation of symbols

  10 Automatic transmission, 12 Transmission case, 20 Electronic circuit device, 22 Shift position sensor, 24 Connector, 28 Volt, 30 Control board, 32 Power supply IC, 34 Solenoid drive circuit, 36 Microcomputer, 40 Case, 42 Bottom, 44 Bolt hole, 46 Base, 48 Radiation fin, 52 Side wall, 54 Upper end surface 54a Inner peripheral side upper end surface, 54b Outer peripheral side upper end surface, 56 Recessed part, 58 Claw part, 60 Cover, 62 Cover body, 66 Convex part , 66a Inner peripheral side shoulder surface, 66b Outer peripheral side shoulder surface, 68 collar part, 69 claw hook part, 72 raised part, 74 through-hole.

Claims (9)

An electronic circuit device in which a circuit board is accommodated in a case having a bottom part and a side wall part and the upper part is opened and a cover for closing the opening of the case is attached,
In the case, a recess is formed over the entire periphery on the upper end surface of the side wall,
In the cover, a convex portion that fits over the entire circumference of the concave portion and a flange that covers at least a part of the outer peripheral surface of the side wall portion are formed,
When the cover is attached to the case by fitting the convex portion into the concave portion using an adhesive, the inner peripheral surface from the concave portion of the concave portion and the inner peripheral surface from the protrusion of the convex portion The recess and / or the protrusion is arranged on the inner periphery so that one of the interval between the gap between the gap and the gap on the outer circumference side of the recess and the gap on the outer circumference side of the projection on the projection is larger than the other. An electronic circuit device, wherein the height of the side surface and the outer peripheral surface are different steps.   The electronic circuit device according to claim 1, wherein a smaller one of the interval between the inner peripheral surfaces and the outer peripheral surface is substantially zero.   The electronic circuit device according to claim 1, wherein an interval between the outer peripheral surfaces is larger than an interval between the inner peripheral surfaces. The electronic circuit device according to any one of claims 1 to 3,
The concave portion is formed so that the inner circumferential surface and the outer circumferential surface have substantially the same height from the depression,
An electronic circuit device in which the convex portion is formed in a step shape in which the height of the inner peripheral surface and the outer peripheral surface is different from each other.   5. The electronic circuit device according to claim 1, wherein the cover is formed so that the flange covers the entire outer peripheral surface of the side wall portion. 6.   6. The electronic circuit device according to claim 1, wherein the cover is made of a material having a linear expansion coefficient different from that of the case. The electronic circuit device according to claim 6,
The case is a metal case,
The electronic circuit device, wherein the cover is a resin cover.   The electronic circuit device according to any one of claims 1 to 7, wherein the circuit board is an electronic control unit for shift control attached to an automatic transmission. The electronic circuit device according to claim 8, wherein
The automatic transmission is an in-vehicle transmission,
In the case, a shift position detection unit that detects a shift position that is displaced according to a driver's operation is accommodated in a state protruding from the opening,
An electronic circuit device, wherein a through hole into which the shift position detecting unit is inserted is formed in the cover.

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