JP2017059692A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device that suppresses dew condensation at a contact portion of a relay 51.SOLUTION: In a motor control device 3 of an electric brake booster, a power module 16 is housed in a housing 11 together with a control module 17. A pair of relay housing chambers 62 are integrally formed in the power module 16 formed of a synthetic resin by relay housing chamber walls 61, and relays 51 are mounted in the relay housing chambers. A heat conducting block 65 is disposed between the top surface 51b of the relay 51 and the bottom surface of the case 12 of the housing 11 and is thermally connected. The top surface 51b of the relay 51 is cooled by heat conduction after the power supply is cut off in an extremely cold district while the contact portion side of the relay 51 is kept warm by an air layer 63 between the contact portion side and the relay housing chamber wall 61, so that dew condensation occurs on the ceiling wall of the relay case and thus dew condensation at the contact portion is suppressed.SELECTED DRAWING: Figure 8

Description

  The present invention relates to an electronic control device including an electromagnetic relay.

  In Patent Document 1, in a relay in which an electromagnet and a contact portion are accommodated in a relay case, a plurality of heat sinks are formed on the ceiling surface of the relay case away from the contact portion in order to suppress condensation at the contact portion. The configuration is disclosed. That is, the temperature of the ceiling surface of the case is made lower than the temperature in the vicinity of the contact portion so that the moisture of the relay case is condensed on the ceiling surface.

  Patent Document 2 discloses a configuration in which the top surface of a relay case is brought into contact with the chassis of a vehicle via a heat conductive sheet in order to release heat generated inside the relay in an ON state to the outside. Has been.

JP 2009-283255 A JP 2014-79093 A

  In an electronic control device in which the circuit board on which the relay is mounted is housed in the exterior member, when used in an extremely cold region, the temperature of the contact portion suddenly drops through the wiring path after the operation is stopped. Condensation may occur on some parts. In the configuration of Patent Document 1 in which the heat sink is formed on the ceiling surface of the relay case, when the entire relay case including the ceiling surface portion is accommodated in the exterior member of the electronic control device, the ceiling surface, the contact portion, Most of the temperature difference cannot be obtained.

  Patent Document 2 does not disclose the prevention of condensation at the contact portion.

This invention
A relay in which an electromagnet and a contact portion opened and closed by the electromagnet are housed in a relay case;
A circuit board on which this relay is mounted;
An exterior member that houses the circuit board;
An electronic control device comprising:
A wall portion that is formed upright from the relay mounting surface of the circuit board so as to constitute a relay housing space into which the relay is fitted, and that has a gap serving as an air layer with the outer surface of the relay case;
A heat conducting member disposed between at least a part of the outer surface of the relay case exposed from the open surface of the relay accommodating space on the front end side of the wall portion, and the inner surface of the exterior member;
It has.

  According to the present invention, in a cold district or the like, after the electronic control device stops operating, the contact portion is kept warm by the air layer formed by the wall portion, and is thermally connected to the exterior member via the heat conducting member. The temperature of a part of the relay case is quickly reduced, and a large temperature difference is obtained. Therefore, dew condensation occurs on the inner surface of the relay case, and dew condensation on the contact portion is suppressed.

The disassembled perspective view which shows the electric brake booster provided with the motor control apparatus which is one Example of this invention. The exploded perspective view of the motor control device of this embodiment. The perspective view of a case single-piece | unit. It is the perspective view of a power module single-piece | unit, Comprising: The perspective view which looked at the power module from the component mounting surface side. Similarly, the top view which looked at the power module simple substance from the component mounting surface side. The enlarged view of the principal part of FIG. Sectional drawing along the AA line of FIG. Sectional drawing of the whole motor control apparatus along the BB line of FIG. Sectional drawing of the whole motor control apparatus along the CC line of FIG. The top view which shows a power module and a cover in the state which removed the case. The enlarged view of the principal part of FIG. Sectional drawing which shows one structural example of a relay.

  Hereinafter, an embodiment in which the present invention is applied to an electronic control device for an electric brake booster will be described in detail with reference to the drawings.

  FIG. 1 is an exploded perspective view showing an electric brake booster 1 including a motor control device 3 which is an electronic control device according to the present invention, and FIG. 2 is an exploded perspective view of the motor control device 3.

  An electric brake booster 1 shown in FIG. 1 is attached to the engine room side of a dash panel (not shown) that partitions the automobile compartment and the engine compartment, and is illustrated according to the depression of a brake pedal provided on the compartment side. A booster mechanism for driving the master cylinder, and an electric motor 2 for driving the piston of the master cylinder (not shown) in the axial direction via a ball screw mechanism; And a motor control device 3 that drives and controls the electric motor 2 based on the state.

  The electric motor 2 has a motor housing 4 made of a metal material such as an aluminum alloy, for example, and a cylindrical outer surface of the motor housing 4 is positioned between the pair of pedestal portions 5 and the pair of pedestal portions 5. And a controller mounting seat portion 6 to be formed. The motor control device 3 is mounted on the controller mounting seat 6 and is mounted and fixed to the motor housing 4 by screwing the device mounting screws 8 arranged at the four corners into the screw holes 7 of the base 5. Yes. The controller mounting seat portion 6 having a substantially rectangular wall shape has an opening 9 inside thereof, and the electric connection between the electric motor 2 side and the motor control device 3 is made through the opening 9. .

  FIG. 1 generally corresponds to the posture of the electric brake booster 1 disposed in the engine room when mounted on the vehicle, and the motor control device 3 is mounted on the upper surface side of the motor housing 4 when mounted on the vehicle. ing.

  As shown in FIG. 2, the motor control device 3 includes a housing 11 corresponding to an “exterior member”. The housing 11 includes a case 12 positioned on the lower side when the vehicle is mounted and a cover 15 positioned on the upper side when mounted on the vehicle. The case 12 has a bottom wall 13 and a peripheral wall 14, and has a substantially rectangular shape in plan view with the upper surface opening upward. The cover 15 has a substantially rectangular shape in a plan view that closes the upper surface opening of the case 12. Inside the housing 11, a power module 16 corresponding to a “circuit board” is housed together with a control module 17 made of another circuit board. Specifically, the power module 16 is positioned near the bottom wall 13 of the case 12, and the control module 17 is laminated and disposed above the power module 16 with a predetermined interval.

  The cover 15 is formed by press-molding a metal plate in a substantially dish shape, and has a flange portion 21 joined to the upper end of the peripheral wall 14 of the case 12 at the periphery, and accommodates the control module 17. Therefore, it has a shape bulging from the flange portion 21 toward the opposite side of the case 12. The cover 15 is fixed to the case 12 by cover mounting screws 22 arranged at four corners.

  As shown in FIG. 3, the case 12 is molded by a so-called die casting method using a metal material having relatively good heat conduction, such as an aluminum alloy. The substantially rectangular peripheral wall 14 of the case 12 includes a first wall portion 14a and a third wall portion 14c that face each other, and a second wall portion 14b and a fourth wall portion 14d that face each other in a form orthogonal to them. Although it is configured, an opening 25 through which the external connector 24 of the power module 16 is inserted is cut out in a substantially U shape in the first wall portion 14a corresponding to one side thereof. In addition, a circular breathing hole 27 to which a breathing filter 26 (see FIG. 1) is attached from the outside is formed at one end of the fourth wall portion 14d. A plurality of cooling fins 28 are formed on the outer surface of the fourth wall portion 14d. The case 12 and the cover 15 are sealed with a sealant applied to the seal groove 29 at the upper end of the peripheral wall 14, and the periphery of the external connector 24 of the power module 16 is similarly applied by applying the sealant. 12 and the cover 15 are sealed.

  The bottom wall 13 of the case 12 is formed with a plurality of substantially cylindrical power module support portions 31 protruding toward the cover 15 at a plurality of locations, and screw holes for attaching the power module 16 to each top portion. 32 is formed.

  Further, at a position corresponding to a switching element mounting region, which will be described later, on the power module 16 side in the bottom wall 13, a block-shaped protruding portion 34 that protrudes from the bottom wall 13 toward the cover 15 side in a substantially rectangular block shape. Is formed. This block-shaped protrusion 34 functions as a heat sink having a large heat capacity. The block-shaped projecting portion 34 is located at a substantially central portion of the case 12 and has a predetermined interval with respect to the first wall portion 14a, the second wall portion 14b, and the third wall portion 14c of the rectangular peripheral wall 14. And are formed integrally and continuously with respect to the fourth wall portion 14d. A plurality of screw holes 32 for attaching the power module 16 are also formed in the vicinity of the four corners of the top surface of the block-shaped protrusion 34.

  A connector insertion hole 35 is formed in an elongated rectangular shape at the end of the block-shaped protrusion 34 on the fourth wall 14d side. Further, a stator terminal insertion hole 36 is formed in the bottom wall 13 between the block-shaped protruding portion 34 and the second wall portion 14b. The stator terminal insertion hole 36 is formed adjacent to the block-shaped projecting portion 34, that is, is formed in an elongated slit shape along the side surface of the block-shaped projecting portion 34 facing the second wall portion 14b. ing.

  The power module 16 is molded using a synthetic resin material. As shown in FIGS. 4 and 5, a metal bus bar (not shown) is formed in a substantially flat plate shape and serves as circuit wiring. A plate-like base portion 41 having a large number inserted on the surface or inside thereof, the external connection connector 24 formed integrally with one end edge of the plate-like base portion 41, and a plane of the plate-like base portion 41 from the plate-like base portion 41. A stator connection terminal portion 43 and a sensor connector portion 44 projecting in the orthogonal direction are provided. As described above, the external connector 24 is exposed to the outside through the opening 25 of the case 12, and is connected to an electronic device on the vehicle side for transmission and reception of signals and electric power. Further, the stator connection terminal portion 43 located substantially at the center of the plate-like base portion 41 passes through the stator terminal insertion hole 36 of the case 12 described above. The sensor connector 44 located on the side of the plate-like base 41 passes through the connector insertion hole 35 of the case 12. The stator connection terminal portion 43 and the sensor connector portion 44 are finally connected to the stator and the sensor on the electric motor 2 side through the opening 9 of the controller mounting seat portion 6 of the electric motor 2, respectively.

  4 and 5 show the lower surface of the power module 16 on the case 12 side, that is, the component mounting surface, on which a large number of electronic components (mainly power system components) are mounted. Specifically, from the plane of the six switching elements (for example, MOSFETs) 46 and the plate-like base 41 constituting a known inverter circuit that converts DC power supplied via the external connector 24 into three-phase AC power. A pair of first electrolytic capacitors 47 having an upright substantially cylindrical shape, and a pair of second electrolytic capacitors having a substantially cylindrical shape which is also upright from the plane of the plate-like base 41 and having a shorter axial length than the first electrolytic capacitor 47. 48, a plurality of ceramic capacitors 49, a plurality of shunt resistors 50 for detecting current, a pair of relays 51 for cutting off power for circuit protection, a normal mode coil 52 serving as a noise filter, and the like are mounted. The six switching elements 46 are collectively arranged in the form of “2 × 3” in a region corresponding to the block-shaped protrusion 34 of the case 12. The pair of relays 51 is disposed at a position opposite to the mounting region of the switching element 46 with the stator connection terminal portion 43 at the substantially central portion interposed therebetween.

  As shown in FIG. 2, the power module 16 is combined with the case 12 in such a posture that the component mounting surface is the lower surface, and a plurality of power module mounting screws 53 are respectively screwed into the screw holes 32 on the case 12 side. It is fixed to the case 12. The peripheral portion of the power module 16 is fixed to the screw hole 32 of the substantially cylindrical power module support portion 31, and the central portion is fixed to the screw hole 32 of the block-shaped protruding portion 34. The various electronic components mounted on the power module 16 are accommodated in a space generated between the power module 16 and the case 12. At this time, the six switching elements 46 are located close to the top surface of the block-shaped protrusion 34, and each package has a block-shaped protrusion via a single heat conductive sheet as will be described later. 34 is joined to the top surface.

  The control module 17 overlaid on the power module 16 is made of a printed wiring board using a resin substrate such as glass epoxy resin or a metal substrate, and a large number of control system electronic components (not shown) are mounted on both sides thereof. It is. As shown in FIG. 2, the control module 17 made of this printed wiring board has through holes 56 penetratingly formed at positions corresponding to a large number of connection terminals 55 extending upward from the upper surface of the power module 16. By soldering the connection terminal 55 and the through hole 56, necessary electrical connection is made between the power module 16. Then, a plurality of snap fit portions 57 integrally formed on the upper surface of the power module 16 engage with the notches 58 on the periphery of the control module 17, whereby the control module 17 is predetermined from the plate-like base portion 41 of the power module 16. It is fixedly held in a state where the interval is maintained.

  Next, the configuration around the relay 51, which is a main part of the present invention, will be further described.

  In this embodiment, the pair of relays 51 mounted on the power module 16 is a normally open type in which the contact is turned on when the electromagnet is energized, and each has a rectangular parallelepiped shape as shown in FIG. . In contrast to the relay 51 having the rectangular parallelepiped shape, the power module 16 made of synthetic resin is integrally formed with a pair of relay accommodating chambers 62 constituted by a relatively thin relay accommodating chamber wall 61. The relays 51 are fitted in the respective relay accommodating chambers 62 corresponding to “spaces”.

  6 and 7 are an enlarged plan view and a cross-sectional view showing a portion of the relay accommodating chamber 62, and the relay accommodating chamber wall 61 is formed of the plate-like base portion 41 of the power module 16 as shown in FIG. It is formed so as to stand vertically from a relay mounting surface 62a at the bottom of a part. And as shown in FIG. 6, the relay accommodating chamber wall 61 is extended so that the circumference | surroundings of the relay 51 may be enclosed in a rectangle.

  Here, for convenience of explanation, for each surface of the relay 51 that forms a rectangular parallelepiped, that is, a hexahedron, the surface facing the relay mounting surface 62a is the bottom surface 51a, and the opposite surface is the top surface 51b. If the pair of surfaces along the short side are called side surfaces 51c and the pair of surfaces along the short side are called end surfaces 51d, the pair of relays 51 are parallel to each other with a relatively small distance between the side surfaces 51. They are arranged next to each other. Note that a plurality of terminals (a fixed contact terminal 74, a movable contact terminal 75, and a coil terminal 76 shown in FIG. 12), which will be described later, of the relay 51 protrude perpendicularly from the bottom surface 51a to the bottom surface 51a. The relay mounting surface 62a is welded or soldered to a bus bar (not shown) passing through the plate-like base 41 of the power module 16 and extending along the upper surface of the plate-like base 41 (the surface opposite to the relay mounting surface 62a). .

  A relay accommodating chamber wall 61 for one relay 51 (indicated by reference numeral 51A in FIG. 6) has a first wall portion 61a along one side surface 51c, and extends perpendicularly from the first wall portion 61a. A second wall 61b along one end face 51d, a third wall 61c extending along the other side 51c of the relay 51, and the other end face of the relay 51, extending orthogonally from the second wall 61b. And a fourth wall portion 61d which is located opposite to 51d and has a substantially U shape in plan view. Therefore, the first wall portion 61a and the third wall portion 61c face each other with the relay 51 interposed therebetween, and the second wall portion 61b and the fourth wall portion 61d face each other with the relay 51 interposed therebetween.

  The relay accommodating chamber wall 61 for the other relay 51 (shown as 51B in FIG. 6) is configured to be substantially symmetrical with the relay accommodating chamber wall 61 for the relay 51A, and similarly, along the one side surface 51c. The first wall 61a, the first wall 61a extending orthogonally from the first wall 61a, the second wall 61b along one end surface 51d of the relay 51, and the second wall 61b extending further orthogonally, A third wall portion 61c along the other side surface 51c of the relay 51, and a fourth wall portion 61d that is positioned opposite to the other end surface 51d of the relay 51 and has a substantially U shape in plan view. . The first wall portion 61a and the third wall portion 61c face each other with the relay 51 interposed therebetween, and the second wall portion 61b and the fourth wall portion 61d face each other with the relay 51 interposed therebetween.

  And the 3rd wall part 61c with respect to one relay 51A and the 3rd wall part 61c with respect to the other relay 51B are mutually connected by a pair of connection part 61e. Each of the second wall portions 61b includes a substantially U-shaped portion at the intermediate portion.

  Accordingly, each of the relay accommodating chambers 62 is configured as a substantially rectangular recessed space surrounding the four surfaces around the relay 51, although the relay accommodating chamber wall 61 is not completely continuous. The relay 51 is inserted from the open surface, and mounted on the relay mounting surface 62a. In this state where the relay 51 is mounted, the top surface 51b of the relay 51 is exposed from the open surface of one end of the relay accommodating chamber 62. The substantially U-shaped recesses in the fourth wall portion 61d and the second wall portion 61b are for fixing the relay 51 more firmly by filling with a relatively high viscosity adhesive after the relay 51 is mounted. In the case where the adhesive is not filled, it is desirable that the fourth wall portion 61d and the second wall portion 61b are formed as flat wall portions.

  Here, the relay accommodating chamber wall 61 is located slightly away from the side surface 51c and the end surface 51d of the relay 51, and a gap serving as an air layer 63 is provided between them. Further, as shown in FIG. 7, the height from the relay mounting surface 62 a to the tip of the relay accommodating chamber wall 61 is slightly lower than the height to the top surface 51 b of the relay 51. The top portion slightly protrudes from the tip of the relay accommodating chamber wall 61. Thus, since the height of the relay accommodating chamber wall 61 is slightly low, the chuck of the automatic assembly machine for assembling the relay 51 is inserted into the relay accommodating chamber 62 while holding the top of the relay 51. It becomes possible to do. The difference in height between the two is desirably set to a minimum dimension capable of gripping the relay 51 by the chuck. Note that the leading edge of the relay accommodating chamber wall 61 has the same height in each part.

  As shown in FIGS. 8 and 9, the pair of relays 51 arranged in the relay accommodating chamber 62 as described above are assembled with the case 12 or the like as the motor control device 3, and the top surface 51 b faces downward as shown in FIGS. 8 and 9. Each top surface 51b faces the bottom wall 13 of the case 12, more specifically, the bottom wall 13 in the region between the stator terminal insertion hole 36 and the second wall portion 14b. Between them, a heat conduction block 65 having a rectangular flat block shape is disposed as a “heat conduction member”. The heat conduction block 65 is made of a rubber-like material or a silicon-based material excellent in heat conduction, and has flexibility and surface adhesiveness. The heat conduction block 65 has an inner surface between the top surface 51b and the bottom wall 13 of the relay 51. It arrange | positions in the state compressed slightly between the side surfaces, and is closely_contact | adhered to each surface by this. Therefore, the top surface 51 b of the relay 51 is thermally connected to the bottom wall 13 of the case 12.

  FIG. 10 shows the power module 16 having the heat conduction block 65 with the case 12 removed, and FIG. 11 shows the enlarged main part of FIG. Thus, in the present embodiment, the heat conduction block 65 has a size that covers the pair of relays 51 with one heat conduction block 65, and in particular, the tip of the relay accommodating chamber wall 61 that surrounds the periphery of the relay 51. Also has a size that can be covered. Accordingly, one surface of the heat conduction block 65 is in contact with both the top surface 51 b of the relay 51 and the tip of the relay accommodating chamber wall 61, so that each surface of the relay 51 and the relay accommodating chamber wall 61 are in contact with each other. The lower end portion of the air layer 63 formed by the gap between the two is closed. As described above, since the height of the relay accommodating chamber wall 61 is lower than the height to the top surface 51b of the relay 51, there is a step between the two. However, the heat conduction block 65 is sufficiently thick (for example, 5 mm). Therefore, high followability to unevenness is obtained, and the difference in height between the two is generally about 1 to 2 mm to absorb the top surface 51b of the relay 51 and the wall of the relay accommodating chamber. It is possible to ensure close contact with both ends of 61.

  Further, as shown in FIGS. 10 and 9, the space between the six switching elements 46, which are heat generating components, and the top surface of the block-like protrusion 34 of the case 12 is thinner than the heat conduction block 65. A sheet-like heat conductive sheet 67 is interposed. This heat conductive sheet 67 is made of a rubber-like material or a silicon-based material excellent in heat conduction similar to the heat conductive block 65, has flexibility and surface adhesiveness, and protrudes from the package surface of the switching element 46 in a block shape. It is in close contact with the top surface of the portion 34. As a result, the heat of the switching element 46 in operation is dissipated to the block-shaped protrusion 34 serving as a heat sink.

  The relay 51 used in the present invention is not necessarily limited to a specific configuration, but an example is shown in FIG. As shown in the figure, the relay 51 has a synthetic resin-made relay case 70 composed of a plate-shaped base member 71 and a box-shaped cap 72 having an open end, and the base member 71 has a plurality of terminals (fixed contacts). A terminal 74, a movable contact terminal 75, and a pair of coil terminals 76) are attached by insert molding. In the illustrated example, the lower surface of the base member 71 is the bottom surface 51 a of the relay 51 described above, and the base member 71 is positioned on the relay mounting surface 62 a side of the power module 16. As described above, the terminals 74 to 76 are disposed through the relay mounting surface 62a, and are welded or soldered to a bus bar (not shown) included in the power module 16. Each of the outer surfaces of the cap 72 is the top surface 51b, the side surface 51c (not labeled in FIG. 12) and the end surface 51d of the relay 51 described above.

  A cylindrical coil 81, an iron core 82, and a substantially L-shaped yoke 83 are located on the upper side (ceiling wall 72 a (top surface 51 b)) of the internal space of the relay case 70 including the base member 71 and the cap 72. An electromagnet 80 is accommodated, and a contact portion 85 composed of a fixed contact 86 and a movable contact 87 is accommodated near the lower side of the internal space of the relay case 70 (base member 71 (bottom surface 51a)). That is, in the relay case 70, the contact portion 85 is located at a position relatively closer to the base member 71 than the coil 81, and the ceiling wall 72 a (in other words, the top surface 51 b) of the cap 72 is reversed to the contact portion. Located at a distance from 85. Therefore, the distance from the contact portion 85 to the ceiling wall 72a (top surface 51b) is larger than the distance from the contact portion 85 to the base member 71 (bottom surface 51a).

  The fixed contact 86 is attached to the end portion of the fixed contact terminal 74 bent in an L shape so as to follow the inner surface of the base member 71, and the movable contact 87 positioned opposite thereto is a leaf spring 88. And is connected to the movable contact terminal 75 via the leaf spring 88. An L-shaped magnetic plate 89 is supported so as to swing around a fulcrum portion 89 a as a swing center, one end 89 a of which opposes the end of the iron core 82, and the other end 89 b to the leaf spring 88. It is linked. Accordingly, when the coil 81 is energized from the coil terminal 76, the magnetic plate 89 swings and presses the leaf spring 88 downward in the drawing, and the movable contact 87 contacts the fixed contact 86. When the coil 81 is de-energized, the movable contact 87 is separated from the fixed contact 86 by the leaf spring 88.

  Such a relay 51 itself is publicly known, and is described in, for example, Japanese Unexamined Patent Application Publication Nos. 2009-283255 and 2004-172036. In the present invention, various known types of relays can be applied.

  In the configuration of the embodiment described above, it is possible to suppress the occurrence of condensation on the contact portion 85 of the relay 51 in an extremely cold region.

  That is, although the relay case 70 has a sealed structure, surrounding moisture penetrates into the relay case 70 due to the moisture permeability of the synthetic resin material constituting the relay case 70. For example, assuming a very cold region that reaches 20 ° below freezing point, the inside of the housing 11 of the motor control device 3 is about 0 ° C. to 5 ° C. during operation of the vehicle (that is, during operation of the motor control device 3). The water in the relay case 70 is in a vaporized state, but thereafter, when the operation of the vehicle is finished and the power source of the motor control device 3 is shut off, the metal members such as the bus bars of the power module 16 and the terminals of the connector The temperature of the contact portion 85 (fixed contact 86, movable contact 87) that is thermally connected to the outside air via the temperature decreases to below freezing point, and the vaporized moisture in the relay case 70 becomes the contact 86. , 87 may cause condensation on the surface. Since the contacts 86 and 87 have a small heat capacity, condensation is likely to occur. If condensation occurs in the contact portion 85 while the vehicle is stopped in this manner, contact failure at the contact portion 85 may occur when the power is turned on to start operation of the vehicle.

  With respect to such a problem, in the configuration of the above-described embodiment, the relay is connected to the metal case 12 exposed to the outside air via the heat conduction block 65 after the power source of the motor control device 3 is shut off in the extremely cold region. Since the top surface 51b of 51 is thermally connected, the temperature of the ceiling wall 72a of the relay case 70 quickly decreases, and the water vaporized in the relay case 70 is condensed on the inner surface of the ceiling wall 72a. . The heat transfer path to the contacts 86 and 87 via the bus bars and the like described above is thin and long, whereas the heat transfer path to the ceiling wall 72a via the heat conduction block 65 is wide and short. Even if it is made of synthetic resin, the temperature rapidly decreases. Therefore, dew condensation at the contacts 86 and 87 located away from the ceiling wall 72a and close to the base member 71 is suppressed.

  Particularly, in the relay 51, the top surface 51b of the relay case 70, that is, the ceiling wall 72a is in contact with the bottom wall 13 of the case 12 via the heat conduction block 65, and the ceiling wall 72a is locally cooled by heat conduction. On the other hand, since the portion other than the ceiling wall 72a is surrounded by the relay accommodating chamber wall 61 via the air layer 63 and is kept warm by the air layer 63, the temperature drop is relatively slow. Therefore, the temperature of the inner surface of the ceiling wall 72a is lowered earlier than the temperature of the contacts 86 and 87, and moisture in the relay case 70 is collected on the ceiling wall 72a as condensation.

  Moreover, in the above-described embodiment, the lower end of the relay accommodating chamber wall 61 that is in an inverted posture as shown in FIGS. 8 and 9 when mounted on the vehicle is covered with the relay case 70 by the heat conduction block 65, The lower end is closed. Since the air heated during the operation of the motor control device 3 is accumulated above the air layer 63 whose lower end is closed (that is, close to the relay mounting surface 62a), the portions near the contacts 86 and 87 of the relay case 70 are effective. Therefore, the temperature decrease of the contacts 86 and 87 becomes slower than the temperature decrease of the ceiling wall 72a.

  Further, in the vehicle-mounted state, the contacts 86 and 87 in the relay case 70 are located above the ceiling wall 72a and the ceiling wall 72a is at the bottom, so that the temperature distribution due to air convection in the relay case 70 However, the upper contacts 86 and 87 are more likely to maintain a higher temperature than the lower ceiling wall 72a. If dew condensation occurs in a portion other than the ceiling wall 72a in the relay case 70, the water drops grow and try to collect on the lower ceiling wall 72a by its own weight. The condensation of 87 is more reliably suppressed.

  In the above-described embodiment, each relay 51 is mounted in such a posture that the terminals 74, 75, 76 of the relay 51 protrude toward the plane of the plate-like base 41 of the power module 16, that is, the relay mounting surface 62 a of the relay accommodating chamber 62. However, the present invention is not limited to this, and can be similarly applied to a configuration in which the relays 51 are attached in a posture in which these terminals 74, 75, and 76 protrude to the side.

  The present invention can be applied not only to the motor control device 3 for the electric brake booster of the above embodiment but also to various electronic control devices.

  As described above, the electronic control device of the present invention includes a relay in which an electromagnet and a contact portion that is opened and closed by the electromagnet are housed in a relay case, a circuit board on which the relay is mounted, and a housing for the circuit board. An exterior member that is formed upright from a relay mounting surface of the circuit board so as to form a relay housing space into which the relay is fitted, and an outer surface of the relay case A wall portion having a gap that becomes an air layer between, at least a part of the outer surface of the relay case exposed from the open surface of the relay accommodating space on the front end side of the wall portion, the inner side surface of the exterior member, And a heat conducting member disposed between the two.

  As a result, after the operation is stopped in an extremely cold region, the temperature of a part of the relay case can be quickly lowered by heat conduction while keeping the contact part in the relay in the air layer, and the moisture in the relay case Condensation can be collected on the inner wall surface of the relay case away from the contact portion, and condensation at the contact portion can be suppressed.

  In a preferred embodiment, the heat conducting member is in contact with both the outer surface of the relay case and the tip of the wall so as to cover the end of the air layer. As a result, the relay case can be more reliably kept warm.

  Moreover, in the posture at the time of use, if the open surface of the relay accommodating space is directed downward, and the surface facing the lower side of the relay case is in contact with the heat conducting member, it is caused by air convection. Also in terms of temperature distribution, the contact portion is more easily maintained at a higher temperature, and the condensed water droplets tend to gather downward due to their own weight, so that dew condensation at the contact portion is suppressed.

  In a preferred embodiment, the height of the wall portion constituting the relay accommodating space is formed to be lower than the height of the relay case, so that the relay is accommodated while holding the relay when the relay is assembled. Can be inserted into the space.

DESCRIPTION OF SYMBOLS 1 ... Electric brake booster 3 ... Motor control apparatus 11 ... Housing 12 ... Case 15 ... Cover 16 ... Power module 51 ... Relay 61 ... Relay accommodation chamber wall 62 ... Relay accommodation chamber 62a ... Relay mounting surface 63 ... Air layer 65 ... Heat Conductive block 71 ... Base member 72 ... Cap 72a ... Ceiling wall 80 ... Electromagnet 81 ... Coil 85 ... Contact part 86 ... Fixed contact 87 ... Movable contact

Claims (4)

A relay in which an electromagnet and a contact portion opened and closed by the electromagnet are housed in a relay case;
A circuit board on which this relay is mounted;
An exterior member that houses the circuit board;
An electronic control device comprising:
A wall portion that is formed upright from the relay mounting surface of the circuit board so as to constitute a relay housing space into which the relay is fitted, and that has a gap serving as an air layer with the outer surface of the relay case;
A heat conducting member disposed between at least a part of the outer surface of the relay case exposed from the open surface of the relay accommodating space on the front end side of the wall portion, and the inner surface of the exterior member;
An electronic control device comprising:   The electronic control device according to claim 1, wherein the heat conducting member is in contact with both the outer surface of the relay case and the tip of the wall portion so as to cover an end portion of the air layer.   3. The electronic control according to claim 1, wherein, in a posture during use, the open surface of the relay accommodating space is directed downward, and a surface of the relay case facing downward is in contact with the heat conducting member. apparatus.   The electronic control device according to claim 1, wherein a height of the wall portion constituting the relay accommodating space is formed to be lower than a height of the relay case.

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