JP2012200141A - Electronic control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electronic control apparatus which enables the size reduction, high output, and long life.SOLUTION: An electronic control apparatus according to this invention includes: a housing 3 having openings at both end parts and made of an insulation resin; a heat sink 5 attached to the one end part of the housing 3 and allowing a semiconductor switching element 2 to be mounted on a surface at the housing 3 side; and a circuit board 4 provided so as to face the heat sink 5. Multiple small current components including a microcomputer 41 controlling driving of the semiconductor switching element 2 are mounted on one surface of the circuit board 4, and multiple large current components including a capacitor absorbing ripples of a current flowing through the semiconductor switching element 2 are mounted on the other surface of the circuit board 4.

Description

  The present invention relates to an electronic control device used in an electric power steering device that assists and energizes a steering device of a vehicle by the rotational force of an electric motor, for example.

Conventionally, a semiconductor switching element (FET), which is a power device, is mounted on a metal substrate, and a connecting member for electrically connecting the metal substrate and a component outside the metal substrate is mounted on the metal substrate. Control devices are known.
For example, in the electronic control device described in Patent Document 1, a power board on which a bridge circuit including a semiconductor switching element for switching the current of an electric motor is mounted, a conductive plate, and the like are insert-molded in an insulating resin. A housing mounted with a large current component, a control board mounted with a small current component such as a microcomputer, a connection member electrically connecting the power board, the housing and the control board, and a power board And a case attached to the heat sink and press-molded with a metal plate to cover the power board, the housing, and the control board.

Japanese Patent No. 3644835 (FIG. 2)

  The electronic control device described in Patent Document 1 requires a power board on which semiconductor switching elements are mounted, a housing on which high current components are mounted, and a control board on which small current components are mounted. There has been a problem of increasing cost, complexity and cost.

  An object of the present invention is to solve the above-mentioned problems, and in addition to downsizing, simplification, and cost reduction, an electronic control device that enables higher output and longer life Is to provide.

  An electronic control device according to the present invention is attached to an insulating resin housing having an opening at each end on both sides, and one end of the housing in which a plurality of connectors are distributed on the side surface, A heat sink in which a power device is mounted on a surface on the housing side, and a circuit board provided to face the heat sink, and one of the plurality of connectors electrically connected to the power device. The power device is disposed in the vicinity of a connector terminal, and the circuit board has a plurality of small current components including a microcomputer for controlling driving of the power device mounted on one surface, and the power device is mounted on the other surface. A plurality of high-current components including a capacitor that absorbs a ripple of the flowing current is mounted. At the periphery of the circuit board, and is arranged at a position that does not overlap with the power device.

  The electronic control device according to the present invention is attached to one end portion of the housing made of an insulating resin having openings at both end portions on both sides and a plurality of connectors distributed on the side surface. And a heat sink having a power device mounted on the surface on the housing, and a circuit board provided to face the heat sink, and one of the plurality of connectors electrically connected to the power device The power device is disposed in the vicinity of the connector terminal in the circuit board, the circuit board is mounted with a plurality of small current components including a microcomputer for controlling the driving of the power device on one surface, and the power device on the other surface. A plurality of high current components including a shunt resistor for detecting a current flowing in the circuit are mounted. At the periphery of the circuit board, and is arranged at a position that does not overlap with the power device.

  According to the electronic control device of the present invention, the power device is mounted on the heat sink, the small current component is mounted on one surface of the circuit board, and the high current component is mounted on the other surface. In addition to cost reduction and cost reduction, high output and long life can be achieved.

It is a disassembled perspective view which shows the electronic control apparatus by Embodiment 1 of this invention. It is a disassembled perspective view when the exploded perspective view which shows the electronic controller of FIG. 1 is seen from the up-down opposite direction. It is a side view when the electronic control unit of FIG. 1 is viewed from the vehicle connector side. It is a side view when the electronic control unit of FIG. 1 is viewed from the motor connector side. It is a perspective view when the housing of the electronic controller of FIG. 1 is seen from the direction in which a heat sink is attached. It is a principal part enlarged view of FIG. FIG. 2 is a block diagram of the electronic control device of FIG. 1. It is a sectional side view of the electronic control unit of FIG. It is a perspective view which shows the assembly | attachment of the electrically-conductive board and connector terminal of the electronic controller of FIG. It is a perspective view which shows the assembly | attachment of the electrically-conductive board and connector terminal of the electronic controller of FIG. FIG. 9 is a side sectional view parallel to the side section of FIG. 8 in the electronic control device of FIG. 1. It is a perspective view which shows the assembly | attachment of the electrically-conductive board and connector terminal of the electronic controller of FIG. It is a perspective view which shows the assembly | attachment of the holding member and spring material of the electronic control apparatus of FIG. FIG. 9 is a side sectional view parallel to the side section of FIG. 8 in the electronic control device of FIG. 1. It is sectional drawing when cut | disconnecting along a right-angled direction with respect to the side cross section of FIG. 8 in the electronic controller of FIG. FIG. 9 is a side sectional view parallel to the side section of FIG. 8 in the electronic control device of FIG. 1. It is a front view which shows the circuit board of the electronic controller of FIG. It is a disassembled perspective view which shows the positional relationship of the heat sink and housing of the electronic control apparatus of FIG. It is a perspective view which shows the positional relationship of the heat sink and housing of the electronic control apparatus of FIG. It is a principal part perspective view of the electronic controller of FIG. It is a sectional side view which shows the electronic controller by Embodiment 2 of this invention. It is a perspective view which shows the modification of the electronic controller by Embodiment 1, 2 of this invention.

Embodiment 1 FIG.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or equivalent members and parts will be described with the same reference numerals.
In this embodiment, an electronic control device 1 used for an electric power steering device that assists and energizes a steering device of a vehicle by the rotational force of an electric motor will be described as an example.
1 is an exploded perspective view showing an electronic control device 1 according to Embodiment 1 of the present invention, FIG. 2 is an exploded perspective view of the electronic control device 1 shown in FIG. 3 is a side view showing the vehicle connector 8 side of the electronic control device 1 of FIG. 1, FIG. 4 is a side view showing the motor connector 9 and sensor connector 10 side of the electronic control device 1 of FIG. 1, and FIG. 1 is a perspective view showing the housing 3 of the electronic control device 1 from the direction in which the heat sink 5 is attached, FIG. 6 is an enlarged view of the main part of FIG. 5, FIG. 7 is a block diagram of the electronic control device 1 of FIG. FIG. 2 is a cross-sectional view of the electronic control device 1 of FIG. 1.

  The electronic control device 1 includes an insulating resin housing 3 having openings at both ends, and an aluminum having an insulating film formed on the surface of the housing 3 attached to one end of the housing 3 using screws 20. A heat sink 5 made of semiconductor, a semiconductor switching element 2 as a power device mounted on the heat sink 5 and pressed against the heat sink 5 by a leaf spring 21, a circuit board 4 provided facing the heat sink 5, and the heat sink 5 The semiconductor switching element 2 and the cover 7 storing the circuit board 4 are provided.

On the surface of the circuit board 4 on the cover 7 side, a plurality of small current components through which a small signal current flows are mounted by soldering. As shown in FIG. 1, the small current component calculates a supplementary torque based on the steering torque of the steering wheel and the vehicle speed of the vehicle, and generates a drive signal corresponding to the supplementary torque by feeding back the motor current. 41, a power supply IC 42 for driving the electronic control device 1, and a driver IC 43 for controlling the operation of the semiconductor switching element 2 respectively.
On the surface of the circuit board 4 on the heat sink 5 side, a plurality of large current components through which a large current for driving the motor flows are mounted by soldering. As shown in FIG. 2, the large current component includes a coil 44 that prevents electromagnetic noise generated during the switching operation of the semiconductor switching element 2 from flowing out, and a capacitor that absorbs a ripple of current flowing through the semiconductor switching element 2. 45, a relay 46 that opens and closes a motor current supplied from the battery 24 to the electric motor 22 via the semiconductor switching element 2 of the bridge circuit, and a shunt resistor 47 that detects the current flowing through the semiconductor switching element 2.

  A current circuit on the circuit board 4 is electrically connected to a bridge circuit configured by the semiconductor switching element 2, a coil 44, a capacitor 45, a relay 46, and a shunt resistor 47, and is configured by a wiring pattern to generate a large current for motor driving. And a small current circuit that is electrically connected to the microcomputer 41, the power supply IC 42, and the driver IC 43 and that is configured by a wiring pattern and through which a small signal current flows.

  The electronic control device 1 is provided on one side of the housing 3 and is electrically connected to the wiring of the vehicle. The electronic control device 1 is provided on the other side of the housing 3 and is electrically connected to the electric motor 22. And a sensor connector 10 adjacent to the motor connector 9 and electrically connected to the torque sensor 23.

As shown in FIG. 3, the vehicle connector 8 includes a power connector terminal 11 formed of copper or copper alloy having a thickness of 0.8 mm, which is electrically connected to the battery 24 of the vehicle, and the wiring of the vehicle. And a signal connector terminal 12 made of phosphor bronze having a thickness of 0.64 mm for inputting and outputting signals.
As shown in FIG. 4, the motor connector 9 includes a motor connector terminal 13 made of copper alloy having a high electrical conductivity of 0.8 mm or phosphor blue, and the sensor connector 10 has a thickness of 0. A sensor connector terminal 14 made of phosphor bronze of .64 mm is provided.

Furthermore, as shown in FIG. 5, the electronic control unit 1 is for power, in which the base part is integrated with the housing 3 by insert molding, and the circuit board 4 and the semiconductor switching element 2 are electrically connected. Conductive plate 6a, output conductive plate 6b, signal conductive plate 6c, and conductive plate in which the base portion is integrated with housing 3 by insert molding, and circuit board 4 and power connector terminal 11 are electrically connected 6d.
In addition, the electronic control device 1 includes a conductive plate 6e that electrically connects the circuit board 4, the signal connector terminal 12 and the sensor connector terminal 14, and a holding member 6f that serves to connect the ground of the circuit board 4 to the heat sink 5. And.

Components such as the power connector terminal 11, the signal connector terminal 12, the motor connector terminal 13, and the sensor connector terminal 14 include a power conductive plate 6a, an output conductive plate 6b, a signal conductive plate 6c, conductive plates 6d and 6e, and a holding member. When the housing 3 is formed by insert molding 6f, the vehicle connector 8, the motor connector 9, and the sensor connector 10 are integrally formed with the housing 3 at the same time.
An attachment leg 3 </ b> L for attaching the electronic control device 1 to a vehicle as an attachment body is formed on the side surface of the opening opposite to the opening of the housing 3 to which the heat sink 5 is attached.

Each terminal of the pair of parallel semiconductor switching elements 2 is connected to the power supply terminal VS, the gate terminal GT1 of the high-side MOSFET 2H, the bridge output terminal OUT, the gate terminal GT2 of the low-side MOSFET 2L, and the ground terminal GND from the right side in FIG. They are arranged in order.
Here, the power supply terminal VS, the bridge output terminal OUT, and the ground terminal GND operate the electric motor 22, so that a large current terminal through which a maximum current of about 50 A flows at the maximum, the gate terminal GT1, and the gate terminal GT2 are the maximum. And a small current terminal through which a small signal current of about 3 A flows, and a large current terminal and a small current terminal are alternately arranged.
As shown in FIG. 8, the terminals OUT of the semiconductor switching elements 2 arranged in parallel are bent in the same shape in a crank shape standing and lying down at two locations in the middle, and are led out in the same direction. The same applies to the other terminals VS, GT1, GT2, and GND.
The terminals VS, GT1, OUT, GT2, and GND of the semiconductor switching element 2 are formed with a width of 0.8 mm, a thickness of 0.5 mm, and a terminal interval of 1.7 mm.

  As shown in FIG. 7, in the semiconductor switching element 2, a high-side MOSFET 2H and a low-side MOSFET 2L are integrated to form a half bridge. The semiconductor switching element 2 constitutes a bridge circuit for switching the current of the electric motor 22 as a set with two half bridges housed in one package.

Further, as shown in FIGS. 5 and 6, the housing 3 is formed with a positioning portion 3 d for positioning the main body of the semiconductor switching element 2 and the housing 3.
A taper is formed at the tip of the positioning part 3d, and a hole 2a provided in the heat spreader part of the semiconductor switching element 2 is guided and inserted into the taper part for positioning. The positioning part 3d also serves as positioning of the terminals VS, GT1, OUT, GT2, and GND in the lead-out direction.
A positioning portion 3e for positioning the terminals VS, GT1, OUT, GT2, GND and the conductive plates 6a, 6b, 6c is formed in the housing 3 in the same manner. The positioning unit 3e performs positioning in a direction perpendicular to the direction in which the terminals VS, GT1, OUT, GT2, and GND are derived. The positioning part 3e is formed outside the terminals VS and GND at both ends of the semiconductor switching element 2, and the tip part is tapered. The outside of each terminal VS, GND of the semiconductor switching element 2 is guided by this taper portion, and positioning of each terminal VS, GT1, OUT, GT2, GND and the conductive plates 6a, 6b, 6c is performed.

  As shown in FIG. 6, the conductive plates 6 a, 6 b, and 6 c are arranged to extend and overlap in the derivation direction from which the terminals VS, GT 1, OUT, GT 2, and GND of the semiconductor switching element 2 are derived, and the terminals VS, GT 1, OUT, GT2 and GND and the conductive plates 6a, 6b, and 6c are disposed on the surface facing the heat sink 5.

After the semiconductor switching element 2 is positioned and fixed by the positioning portions 3d and 3e, the terminals VS, GT1, OUT, GT2, and GND and the conductive plates 6a, 6b, and 6c are welded by, for example, laser welding.
Laser welding is performed by irradiating the laser LB toward the surfaces of the terminals VS, GT1, OUT, GT2, and GND from the direction in which the heat sink 5 is attached before the heat sink 5 is attached.
As shown in FIG. 6, the base end portion of the power conductive plate 6a is connected to the power supply terminal VS of the semiconductor switching element 2 and the tip end of the ground terminal GND. The proximal end portion of the output conductive plate 6b is connected to the distal end portion of the bridge output terminal OUT. The base end portion of the signal conductive plate 6c is connected to the tip end portions of the gate terminals GT1 and GT2, respectively.

FIG. 9 shows a perspective view of the conductive plates 6a, 6b, 6c and peripheral components connected to them.
Press-fit terminals 6ap, 6bp, 6cp are formed on the conductive plates 6a, 6b, 6c, respectively. The circuit board 4 has a wiring pattern made of copper foil and a plurality of through holes 4a electrically connected to the wiring pattern by copper plating on the inner surface. The press-fit terminals 6ap, 6bp, 6cp are connected to the circuit board 4. The terminals VS, GT1, OUT, GT2, GND of the semiconductor switching element 2 and the wiring pattern of the circuit board 4 are electrically connected by being press-fitted into the respective through holes 4a of the substrate 4.

The power conductive plate 6a and the output conductive plate 6b are formed of rolled copper or a copper alloy. However, when the conductive plates 6a and 6b and the terminals VS, OUT, and GND of the semiconductor switching element 2 are welded, a large current flows through the conductive plates 6a and 6b, so that the conductive plates 6a and 6b have a sufficient volume. There is a need to.
However, it is difficult to increase the plate thickness from the viewpoint of forming the press-fit terminal and press working. Therefore, in this embodiment, the thickness of the conductive plates 6a and 6b, which are conductive plates for power, is set to 0.8 mm, which is the same as the width of the terminals VS, OUT, and GND, and the plate width is formed wider than the plate thickness. The terminals VS, OUT, and GND of the switching element 2 are welded.
The signal conductive plate 6c is formed of the same plate material as the power conductive plate 6a and the output conductive plate 6b through which a large current flows, although it is not necessary to consider the reduction of electric resistance because a small current flows. Has been.

As shown in FIGS. 8 and 9, the output conductive plate 6 b is connected to the bridge output terminal OUT of the semiconductor switching element 2.
Further, the end 13a of the motor connector terminal 13 is connected to the end opposite to the base end. Similarly to the connection between the output conductive plate 6b and the bridge output terminal OUT of the semiconductor switching element 2, the end portion 13a of the motor connector terminal 13 faces the heat sink 5 at the end portion of the output conductive plate 6b. The laser LB is irradiated and welded from the direction in which the heat sink 5 is attached toward the surface of the motor connector terminal 13.
The motor current from the bridge output terminal OUT of the semiconductor switching element 2 is configured to flow directly to the electric motor 22 via the motor connector terminal 13 without passing through the circuit board 4.
A press-fit terminal 6 bp extending toward the circuit board 4 is formed in the intermediate portion of the output conductive plate 6 b, and a signal for monitoring the voltage of the motor connector terminal 13 is output to the circuit board 4.

FIG. 10 shows a perspective view of the power supply conductive plate 6d and the peripheral components connected thereto.
As shown in FIGS. 8 and 10, the end 11 a of the power connector terminal 11 is connected to the power conductive plate 6 d. Similarly to the connection of the output conductive plate 6b and the end portion 13a of the motor connector terminal 13, the power connector terminal 11 is disposed on the surface of the end portion of the power supply conductive plate 6d facing the heat sink 5. Laser LB is irradiated and welded from the direction in which the heat sink 5 is attached toward the surface of the end portion 11 a of the power connector terminal 11.
A press-fit terminal 6dp extending toward the circuit board 4 is formed in the intermediate portion of the power supply conductive plate 6d, and the press-fit terminal 6dp is press-fitted into the through hole 4a of the circuit board 4 so The wiring pattern is electrically connected. The current of the battery 24 is supplied to the circuit board 4 via the power connector terminal 11, the power conductive plate 6d, and the press fit terminal 6dp.

11 is a cross-sectional view taken along the vehicle connector 8 and the sensor connector 10 in parallel with FIG. 8, and FIG. 12 is a perspective view of each conductive plate 6e and peripheral components connected thereto. is there.
As shown in FIGS. 11 and 12, the conductive plate 6 e is overlapped with the signal connector terminal 12 and the end portions 12 a and 14 a of the sensor connector terminal 14, and this mating surface is in the vicinity of the heat sink 5 and parallel to the heat sink 5. Is formed.
At this time, the end portions 12a and 14a of the signal connector terminal 12 and the sensor connector terminal 14 are arranged on the heat sink 5 side, and the end portion 12a of the signal connector terminal 12 and the end portion of the sensor connector terminal 14 from the direction in which the heat sink 5 is attached. Laser LB is irradiated and welded toward the surface 14a.
The conductive plate 6e has a press-fit terminal 6ep formed at the end opposite to the welded portion, and the press-fit terminal 6ep is press-fitted into the through hole 4b of the circuit board 4 so as to be inserted into the conductive plate 6e. The connected signal connector terminal 12 and sensor connector terminal 14 are electrically connected to the wiring pattern of the circuit board 4.

13 is a perspective view of the holding member 6f and peripheral components connected to the holding member 6f. FIG. 14 is a cross-sectional view taken along the center of the holding member 6f, which is parallel to FIG.
The holding member 6 f has a function of connecting the ground of the circuit board 4 to the heat sink 5. However, since the insulating film 52 is formed on the surface of the heat sink 5, the holding member 6f cannot be brought into direct contact with the heat sink. Therefore, the circuit board 4 and the heat sink 5 are electrically connected via the screw 20 and the leaf spring 21.
The leaf spring 21 shown in FIG. 13 is formed of a conductor such as a stainless steel plate for springs or phosphor bronze for springs, and is provided with a slit 21s at one end. The holding member 6f is press-fitted and fixed to the slit 21s, whereby the holding member 6f and the leaf spring 21 are electrically connected. As shown in FIG. 14, the leaf spring 21 to which the holding member 6 f is fixed is disposed between the housing 3 and the head of the screw 20, and is fastened and fixed to the heat sink 5 together with the housing 3.
Since the screw hole provided in the heat sink 5 is not insulated, the holding member 6f and the heat sink 5 are electrically connected.
A press-fit terminal 6fp is formed at the tip of the holding member 6f, and the press-fit terminal 6fp is press-fitted into the through hole 4a of the circuit board 4.
With this configuration, the wiring pattern of the circuit board 4 and the heat sink 5 are electrically connected via the press-fit terminal 6fp, the holding member 6f, the leaf spring 21, and the screw 20.

As shown in FIGS. 8 and 11, in this embodiment, the press-fit terminals 6ap, 6bp, 6cp, 6dp, and 6ep are disposed on the cover 7 side, and the laser welded portion is disposed on the heat sink 5 side.
With this configuration, the distance between the press-fit terminals 6ap, 6bp, 6cp, 6dp, and 6ep and the laser welded portion is increased, so that the influence of heat, reflected light, and shielding gas generated during laser welding is affected by the press-fit terminals 6ap and 6bp. , 6cp, 6dp, 6ep can be reduced.
Further, since the insulating resin 3a and the circuit board 4 are interposed between the press-fit terminals 6ap, 6bp, 6cp, 6dp, 6ep and the laser welded portion, the reflected light generated at the time of laser welding causes the press-fit terminals 6ap, It is difficult to reach 6 bp, 6 cp, 6 dp, 6 ep.
Further, the terminals VS, GT1, OUT, GT2, GND, 11, 12, 13, and 14 are center lines that pass through the centers of the press-fit terminals 6ap, 6bp, 6cp, 6dp, and 6ep (for example, dotted lines in FIG. 11). On the other hand, it is welded to the conductive plates 6a, 6b, 6c, 6d and 6e at the welded portions on the lines separated in parallel. As described above, the press-fit terminals 6ap, 6bp, 6cp, 6dp, and 6ep are press-fitted into the circuit board 4 by placing the welded part at positions away from the centers of the press-fit terminals 6ap, 6bp, 6cp, 6dp, and 6ep. It is possible to prevent the press-fitting load from directly acting on the welded portion, and to prevent distortion of the welded portion or occurrence of peeling.
The circuit board 4 is mechanically held by press-fit terminals 6ap, 6bp, 6cp, 6dp, 6ep, and 6fp being press-fitted into the through hole 4a.

  Further, since the base portions of the respective conductive plates 6a, 6b, 6c, 6d, 6e, 6f are insert-molded in the insulating resin 3a of the housing 3, press-fit terminals 6ap, 6bp, 6cp, 6dp, 6ep, 6fp 8, 11, and 14, the insulating resin 3 a is interposed between the heat sink 5 and the pressure input can be received by the heat sink 5. Yes. However, a slight gap is generated between the insulating resin 3a and the heat sink 5 due to manufacturing accuracy.

  In the press-fit press-fitting, the relative height accuracy between the press-fit terminals 6ap, 6bp, 6cp, 6dp, 6ep, 6fp and the circuit board 4 is important, but due to a slight gap between the insulating resin 3a and the heat sink 5. Since the relative height accuracy deteriorates, an adhesive (not shown) is applied to the gap to eliminate the influence of the gap.

In this embodiment, the power conductive plate 6a has two press-fit terminals 6ap, the output conductive plate 6b has one press-fit terminal 6bp, and the signal conductive plate 6c has one press-fit terminal 6cp. Each is formed, and seven press-fit terminals 6ap, 6bp, 6cp are arranged for one semiconductor switching element 2.
Further, by arranging the press-fit terminals 6ap, 6bp, 6cp of the adjacent conductive plates 6a, 6b, 6c in a staggered manner, the distance between the press-fit terminals 6ap, 6bp, 6cp is increased, so that each terminal 6a, 6b. , 6c is prevented from being short-circuited.

The conductive plate 6d has two press-fit terminals 6dp for each power connector terminal. The conductive plate 6e has six press-fit terminals to be connected to the signal connector terminal 12 and sensor connector terminals 14. There are five press-fit terminals to be connected, for a total of 11 press-fit terminals 6ep.
In addition, one press-fit terminal 6fp is formed on the holding member 6f. The hole diameter of the through hole 4a of the circuit board 4 into which the press-fit terminals 6ap, 6bp, 6cp, 6dp, and 6fp are press-fitted is 1.45 mm, and the hole diameter of the through-hole 4b into which the press-fit terminal 6ep is press-fitted is 1 mm. ing.

  In the electronic control device 1 configured as described above, when the microcomputer 41 generates a drive signal, a current flows in the circuit and heat is generated from each part. At this time, the amount of heat generated by the coil 44, the capacitor 45, the relay 46, and the shunt resistor 47 electrically connected to the large current circuit is the microcomputer 41, the power supply IC 42, and the driver electrically connected to the small current circuit. It is larger than the calorific value of IC43. If these parts are arranged in the same space, the microcomputer 41, the power supply IC 42, and the driver IC 43 that generate a small amount of heat are affected by the heat generated from the coil 44, the capacitor 45, the relay 46, and the shunt resistor 47 that generate a large amount of heat. It will rise.

  In this embodiment, a coil 44, a capacitor 45, a relay 46, and a shunt resistor 47, which are large current components, are provided on the surface of the circuit board 4 on which a microcomputer 41, a power supply IC 42, and a driver IC 43, which are small current components, are mounted. The coil 44, the capacitor 45, and the relay 46 are arranged on the circuit board 4 so as to face the surface on which the switching element 2 of the heat sink 5 is mounted.

The positional relationship of the current components on the circuit board 4 in this embodiment is shown in FIGS. 15 shows another cross section parallel to FIG. 8, and FIG. 16 shows a cross section cut in a direction perpendicular to FIG.
As shown in FIG. 15, the coil 44, the capacitor 45, and the relay 46 are disposed in a space surrounded by the circuit board 4, the heat sink 5, and the inner wall surface of the housing 3.
As shown in FIG. 16, the shunt resistor 47 and the semiconductor switching element 2 mounted on the heat sink 5 are also arranged in the same space.

The surface of the circuit board 4 on which the microcomputer 41, the power supply IC 42, and the driver IC 43, which are small current components, are mounted is arranged so as to face the cover 7. That is, the microcomputer 41, the power supply IC 42, and the driver IC 43 are disposed in a space surrounded by the circuit board 4 and the inner wall surface of the cover 7.
With this arrangement, the internal space of the electronic control device 1 formed by the housing 3, the heat sink 5, and the cover 7 is divided into a space A storing a large current component and a space B storing a small current component by the circuit board 4. It will be divided into two.
In the space A, a large current component through which a large current flows, that is, a large current component that generates a large amount of heat, is stored, so that the temperature inside the space increases. On the other hand, in the space B, a small current component with a small calorific value is stored, and the circuit board 4 serves as a heat insulating material to insulate the heat in the space A. Therefore, the temperature inside the space B is low. Become.
The microcomputer 41, the power supply IC 42, and the driver IC 43 incorporate a small and high-performance integrated circuit, and are weak against heat as compared with other current components.
Therefore, by arranging these components in the low temperature space B, it is possible to prevent a temperature rise due to heat reception.

Among the components constituting the electronic control unit 1, the temperature becomes the lowest in the housing 3 formed of a non-heating element and an insulating resin having a low thermal conductivity.
Since a temperature boundary layer develops in the vicinity of the inner wall surface of the housing 3, a low-temperature space having a temperature lower than that of the other part is formed in the vicinity of the inner wall surface. As a matter of course, the vicinity of the inner wall surface is close to the outside air, so that heat is easily radiated to the outside air.
That is, if the current components mounted on the circuit board 4 are arranged at the peripheral edge of the circuit board 4, the current components are arranged near the inner wall surface of the housing 3, so that heat dissipation is promoted and temperature rise is suppressed. Can do. In particular, when current components are arranged at the corners of the circuit board 4, the current components are close to the two surfaces of the inner wall surface of the housing 3 and can be radiated more effectively. , Higher output and longer life.

FIG. 17 shows a front view of the circuit board 4 in this embodiment.
As can be seen from FIG. 17, since the capacitor 45 is disposed at the corner of the circuit board 4, it is disposed near the corner of the inner wall of the housing 3 during assembly.
A shunt resistor 47 is also disposed at the edge of the circuit board 4 and is disposed near the inner wall of the housing 3 during assembly.
The components arranged on the peripheral edge of the circuit board 4 are not limited to the capacitor 45 and the shunt resistor 47. For example, the coil 44, the relay 46, the microcomputer 41, the power supply IC 42, and the driver IC 43 have no problem.
There is no problem even if a plurality of large current components and small current components are arranged on the peripheral edge of the circuit board 4.

16 and 17, the connection point between the capacitor 45 and the wiring formed on the circuit board 4 and the connection point between the shunt resistor 47 and the wiring formed on the circuit board 4 are close to each other. ing. Therefore, the capacitor 45 and the shunt resistor 47 are arranged close to each other on the circuit board 4.
When the connection distance between the capacitor 45 and the shunt resistor 47 is increased, the inductance of the system is increased and noise is increased. Therefore, the connection distance between the capacitor 45 and the shunt resistor 47 is arranged within 3 mm.

The heat sink 5 includes a heat sink body 51 and an alumite film 52 that is an insulating film formed on the surface of the heat sink body 51.
The heat sink 5 manufactures a heat sink material in which an alumite film 52 is previously formed on the entire surface of an extruded shape formed by extruding aluminum or an aluminum alloy from a die, and cuts the heat sink material to a desired length with a cutting machine. It is formed by machining such as drilling.
In this manufacturing method, since it is not necessary to form the alumite film 52 for each heat sink, the manufacturing process is simplified and the manufacturing cost is reduced.
Anodized is a surface treatment method that forms an insulating oxide film on the surface by anodizing aluminum or an aluminum alloy.

Metal oxide films generally have a high emissivity of about 0.8 to 0.9.
That is, since heat radiation by natural air cooling and heat radiation by radiation occur on the surface of the heat sink 5 that has been subjected to the alumite treatment, high heat radiation performance can be obtained.
Since the heat sink 5 is manufactured by cutting the material on which the alumite film 52 is formed, the end surface 5a is not subjected to an alumite treatment. In general, since the emissivity of metal is about 0.1 to 0.2, even if the end face 5a of the heat sink 5 is exposed to the outside, sufficient heat dissipation performance cannot be obtained.
Therefore, the end surface 5a of the heat sink 5 is disposed so as to face and face the inner wall surface 3c of the opening of the housing 3 made of insulating resin.
18 and 19 are perspective views showing the positional relationship between the inner wall surface 3c of the housing 3 and the end surface 5a of the heat sink 5 in this embodiment.
Insulating resin has a sufficiently high thermal emissivity compared to metal. Further, the surface area of the housing 3 is sufficiently larger than the surface area of the end surface 5 a of the heat sink 5.

Therefore, by bringing the end surface 5a of the heat sink 5 and the inner wall surface 3c of the housing 3 into surface contact, a large amount of heat of the heat sink 5 flows smoothly through the end surface 5a to the housing 3 having a large heat radiation area and high thermal emissivity. Therefore, it is possible to obtain higher heat dissipation performance than the case where it is discharged to the outside through the housing 3 and the end face 5a of the heat sink 5 is directly exposed to the outside.
In addition, as shown in FIG. 19, one side surface 5b of the heat sink 5 having the alumite film 52 on the surface is configured to be exposed to the outside.

In the heat sink 5, since the heat sink body 51 is made of aluminum or aluminum alloy having high thermal conductivity, the heat resistance of the heat sink 5 itself can be almost zero.
Further, since the alumite film 52 is formed of alumina oxide (AL ₂ O ₃ ) and has a very thin film thickness of about 10 μm, the thermal resistance can be regarded as almost zero.

An alumite film 52 is formed on the surface of the heat sink 5 except for the end face 5a.
That is, the alumite film 52 is also formed on the surface on which the semiconductor switching element 2 is mounted and on the surface facing the terminals VS, GT1, OUT, GT2, and GND of the semiconductor switching element 2. Anodized has a role as an insulating film in addition to a role as an oxide film for improving emissivity.
Although a high current flows through the semiconductor switching element 2, a short circuit with the heat sink 5 can be prevented because the alumite film 52 is formed on the surface of the heat sink 5.
Even if an insulation failure due to a crack or the like of the alumite film 52 occurs in the vicinity of the semiconductor switching element 2, the surface of the heat sink 5 is insulated by the alumite film 52 and the housing 3. Therefore, the electronic control device 1 with improved insulation performance can be obtained without being electrically short-circuited with the semiconductor switching element 2.

In this embodiment, the heat sink 5 is manufactured using an extruded profile, but may be manufactured using a hot or cold-rolled plate.
Further, although the insulating film is the alumite film 52, a precoated insulating resin may be used as the insulating film.
Further, the heat sink surface of aluminum or aluminum alloy may be painted with a paint.

When the semiconductor switching element 2 is installed on the heat sink 5, a heat conductive adhesive (not shown) is interposed and fixed between the heat spreader portion of the semiconductor switching element 2 and the anodized film 52 of the heat sink 5. Since there are small irregularities on the surfaces of the heat sink 5 and the heat spreader, even if the heat spreader part is brought into close contact with the heat sink 5, a slight gap is generated, and the true contact area is smaller than the apparent contact area.
When the contact area is reduced, the heat resistance in the heat transfer path when the heat generated in the semiconductor switching element 2 is transferred to the heat sink 5 is increased, so that heat dissipation from the semiconductor switching element 2 is hindered.
Therefore, by interposing a thermally conductive adhesive in the gap, the thermal resistance between the semiconductor switching element 2 and the heat sink 5 can be reduced, and the heat dissipation performance can be promoted.
Moreover, when the semiconductor switching element 2 and the heat sink 5 are fixed with a heat conductive adhesive, for example, when an external force is applied to the electronic control device 1 or vibration is generated, a welded portion of the semiconductor switching element 2 is applied. Such stress is reduced.

In addition to the role of connecting the ground of the circuit board 4 and the heat sink 5, the leaf spring 21 has a role of fixing the semiconductor switching element 2 to the housing 3.
FIG. 20 shows a perspective view of a main part showing the leaf spring 21 and its surrounding parts.
As shown in FIGS. 14, 16, and 20, the locking portion 21 b of the leaf spring 21 is locked to the holding portion 3 b of the housing 3 and is fixed to the heat sink 5 with screws 20 through the housing 3. Yes.
At this time, the holding portion 21 a of the leaf spring 21 is pressed against the resin package surface of the semiconductor switching element 2. As a result, since the heat conductive adhesive spreads thinly and uniformly by the pressing of the leaf spring 21, the difference in thermal resistance variation between the alumite film 52 of the heat sink 5 and the semiconductor switching element 2 can be reduced.
Furthermore, since the semiconductor switching element 2 is fixed by pressing the leaf spring 21 in addition to the adhesive force of the heat conductive adhesive, the alumite film 52 is peeled off due to a difference in thermal expansion between the heat sink 5 and the semiconductor switching element 2. Further, peeling of the alumite film 52 due to external force / vibration can be prevented.

  The semiconductor switching element 2 has a heat spreader portion electrically connected to the bridge output terminal OUT inside, but is electrically insulated from the heat sink 5 by an alumite film 52 and a high thermal conductive adhesive.

The cover 7 is formed of the same insulating resin as that of the housing 3 and is welded to the opening of the housing 3 by an ultrasonic welding machine.
The cover 7 and the housing 3 may be welded by vibration welding using a vibration welding machine.
In the vibration welding, the cover 7 is reciprocally oscillated along the surface direction of the joint surface between the cover 7 and the housing 3, and the resin of the cover 7 and the housing 3 is melted and joined to each other by frictional heat.
Vibration welding is applied when the joint surface between the cover 7 and the housing 3 is large.
Further, laser welding by a laser welding machine may be used instead of the ultrasonic welding machine.
In laser welding, the cover 7 is made of a material having a high laser transmittance, and the housing 3 is made of a material having a high laser absorption rate.
When the laser beam is irradiated from the cover 7 side, the laser beam passes through the cover 7 and is absorbed by the joint surface of the housing 3 to generate heat. The heat is also conducted to the cover 7 side, the cover 7 also generates heat, and is melted and welded to the joint surface between the cover 7 and the housing 3.
Laser welding cannot be used in resin molding with large warps and sink marks because it is difficult to focus the laser on the joint surface, but in the case of resin molding with small warps and sink marks, the welding itself generates burrs. There is no vibration and no vibration is transmitted to the internal parts.

As described above, according to the electronic control device 1 of the first embodiment, since the semiconductor switching element 2 is mounted on the heat sink 5, the heat dissipation of the semiconductor switching element 2 is improved and it has been conventionally required. The power substrate for mounting the semiconductor switching element 2 is not required, and the overall height is reduced and the size is reduced.
The circuit board 4 has a plurality of small current components including a microcomputer 41 that controls driving of the semiconductor switching element 2 mounted on one surface, and a plurality of large current components including a capacitor 45 mounted on the other surface. Since a large current component and a small current component are mounted on one circuit board, the overall height is further reduced and the size is reduced.
In addition, a large current component with a large amount of heat generation and a small current component with a small amount of heat generation are separated via the circuit board 4, and the small current component weak in heat resistance is suppressed from the influence of heat from the large current component, and is electronically controlled. The life of the device 1 can be extended.
In addition, since the small current component is mounted on the surface opposite to the surface facing the semiconductor switching element 2, the influence of heat from the semiconductor switching element 2 through which a large current flows is suppressed, and the electronic control device 1 is more effective. Long life.

  In addition, since the capacitor 45 and the shunt resistor 47 are disposed at the edge of the circuit board 4, the heat dissipation of the capacitor 45 and the shunt resistor 47 is improved.

  Further, since the circuit board 4 is mounted with the shunt resistor 47 and the capacitor 45 close to each other, the electrical connection distance between the shunt resistor 47 and the capacitor 45 can be shortened, and the inductance of the system can be kept small. And generation of noise can be suppressed.

  Moreover, since the heat sink 5 has the alumite film 52 formed on the surface on which the semiconductor switching element 2 is mounted and the back surface thereof, the heat emissivity of the heat sink 5 is increased, and the heat radiation of the heat sink 5 is improved.

  Further, since the exposed end surface 5a of the heat sink 5 that does not have the alumite film 52 is in surface contact with the inner wall surface 3c of the housing 3, a large amount of heat from the heat sink 5 has a large heat radiation area through the end surface 5a, and heat radiation. The heat flows smoothly through the housing 3 having a high rate and is discharged to the outside through the housing 3, so that the heat dissipation of the heat sink 5 is improved.

  Further, the heat sink 5 has a high heat dissipation property because the alumite film 52 having almost zero thermal resistance is formed on the surface of the heat sink body 51 made of aluminum or aluminum alloy having high thermal conductivity.

Further, since the semiconductor switching element 2 is fixed to the surface of the anodized film 52 using a heat conductive adhesive, the thermal resistance between the semiconductor switching element 2 and the heat sink 5 is reduced, and the semiconductor switching element 2 Heat dissipation is improved.
Further, when an external force is applied to the semiconductor switching element 2, stress on the welded portion of the semiconductor switching element 2 is reduced, and the connectivity of the semiconductor switching element 2 to the heat sink 5 is improved.

  Further, since the semiconductor switching element 2 is pressed against the heat sink 5 by the leaf spring 21, the semiconductor switching element 2 and the heat sink 5 are firmly coupled, and the semiconductor switching element 2 due to a difference in thermal expansion and external force / vibration between the two. Occurrence of peeling can be prevented.

  Further, since the leaf spring 21 is locked to the housing 3 and is fixed to the heat sink 5 with the screw 20 via the housing 3, the leaf spring 21 reliably presses the semiconductor switching element 2 against the heat sink 5. be able to.

Embodiment 2. FIG.
FIG. 21 is a cross-sectional view showing the main parts of the electronic control apparatus 1 according to Embodiment 2 of the present invention.
The electronic control device 1 shown in FIG. 21 is different from the structure shown in FIG. 15 in that a capacitor 45, which is a large current component, is in contact with the heat sink 5 via an inclusion 45a, The computer 41, the power supply IC 42, and the driver IC 43 are in contact with the cover 7 via inclusions 41a, 42a, and 43a, respectively.
Other configurations are the same as those of the first embodiment.

In the electronic control device 1 according to the first embodiment shown in FIG. 15, the current component is in contact with the circuit board 4 only at the wiring pattern portion, and the surface of the other current component is formed by the housing 3, the heat sink 5 and the cover 7. Exposed to the air inside the case.
Therefore, most of the heat generated in the current component is radiated to the internal air of the housing 3. The thermal conductivity of air is 0.03 W / mK at room temperature, which is smaller than the thermal conductivity of solids.
Further, the inside of the housing is sealed, and the air convection generated inside is a natural convection caused by a difference in air density due to a temperature difference. The flow rate of natural convection is generally 0.1 m / s or less, and the heat dissipation effect is very small.
That is, if air is present around the current component, the thermal resistance increases and the heat dissipation performance is significantly deteriorated.

Therefore, the capacitor 45 is brought into contact with the heat sink 5 via the inclusion 45a, and the microcomputer 41, the power supply IC 42 and the driver IC 43 are brought into contact with the cover 7 via the inclusions 41a, 42a and 43a, respectively. The generated heat can be directly radiated to the outside by heat conduction without relying on air convection with low heat dissipation performance.
However, since the current component is fixed to the circuit board 4 with solder, it is difficult to sufficiently ensure the height accuracy of the current component. If the height is low, a sufficient contact effect cannot be obtained. Conversely, if the height is too high, an excessive force is applied during assembly, and the current component is destroyed.
Even if the current component is brought into contact with the heat sink 5 or the cover 7, since the surface of the current component has many minute irregularities, the true contact area becomes smaller than the apparent contact area. As the contact area decreases, the thermal resistance increases, and as a result, it becomes difficult to obtain sufficient heat transfer performance.

Therefore, as shown in FIG. 21, when the current component and the heat sink 5 or the cover 7 are brought into contact with each other, a means for contacting the component with a gel or elastic material interposed between the objects is effective. . Examples of the inclusions that meet the conditions include thermally conductive grease, thermally conductive adhesive, heat transfer sheet, and heat radiation rubber.
Since these substances can be deformed by pressurization, if an inclusion is applied or pasted to the target position, it is sandwiched between the current component and the heat sink 5 or the cover 7 during assembly. By the pressure deformation, the gap is filled and the parts can be brought into contact with each other.

In addition, the inclusions 41a, 42a, 43a, 45a of this embodiment are composed of any one of thermally conductive grease, a thermally conductive adhesive, a heat transfer sheet, and a heat radiation rubber, and the heat radiation performance is improved. In addition to this, the temperature rise speed of the current component can be delayed.
Since the electronic control device 1 operates by sensing the steering torque of the steering wheel, the electronic control device 1 repeats an unsteady operation in which the current value switches instantaneously.
That is, it is assumed that a large current flows instantaneously, but it is conceivable that a small current component having a small heat capacity will cause a problem due to a sudden rise in temperature.
On the other hand, the current component and the heat sink 5 or the cover 7 are brought into contact with each other through the inclusions 41a, 42a, 43a, 45a, so that the heat capacity of the current component is apparently increased. Can slow down.
If the handle operation is performed within the same time, the presence of the inclusions 41a, 42a, 43a, 45a increases the heat capacity and slows the temperature rise speed of the current component. As a result, the temperature rise value can be reduced. it can.

Further, in the electronic control device 1 of the first embodiment shown in FIG. 15, since the current component is in contact with the circuit board 4 only at the wiring pattern portion, only the wiring pattern supports the current component. Therefore, in this configuration, since the current component needs to be supported at a very small portion, stress due to external force, vibration, or thermal stress due to thermal expansion may occur, and the current component may be damaged or peeled off.
On the other hand, in this embodiment, since the inclusions 41a, 42a, 43a, 45a have a gel-like or elastic characteristic, the area for supporting the current component increases. The influence of the generated stress or the thermal stress due to thermal expansion can be reduced. In addition, vibration absorption by the spring effect of the inclusions 41a, 42a, 43a, and 45a and the effect of suppressing thermal expansion also occur.

In this embodiment, the capacitor 45 is in contact with the heat sink 5 via the inclusion 45a, but may be in contact with the housing 3.
Similarly to the capacitor 45, the relay 46, which is a large current component, may be brought into contact with the heat sink 5 or the housing 3 via an inclusion.

  As described above, according to the electronic control device 1 of the second embodiment, the cover 7 is attached to the end portion of the housing 3, and the housing 3, the heat sink 5, and the cover 7 constitute a housing. Since the component and the small current component are in contact with the inner wall surface of the housing via the inclusions 41a, 42a, 43a, and 45a having thermal conductivity, the heat generated from each current component is convected with low heat dissipation performance. The heat can be directly radiated to the outside by heat conduction.

  In addition, since the inclusions 41a, 42a, 43a, and 45a are made of a gel or an elastic material, the variation in the gap between the housing and the large current component and the small current component is absorbed by the deformation during assembly. Is prevented from being applied to the casing, the large current component and the small current component.

In the first and second embodiments, the surface exposed to the outside of the heat sink 5 is a flat surface as shown in FIG. 19, but by providing the radiation fins 5c as shown in FIG. May be improved.
In addition, each terminal VS, GT1, OUT, GT2, and GND of the semiconductor switching element 2 and the connection terminals 11a, 12a, 13a, and 14a and the conductive plates 6a, 6b, 6c, 6d, and 6e are joined by laser welding. Other welding methods such as resistance welding and TIG welding may be used.
Moreover, ultrasonic bonding other than welding may be used.
The semiconductor switching element 2 includes a half bridge in which a high-side MOSFET 2H and a low-side MOSFET 2L are integrated in one package, and a bridge circuit for switching the current of the electric motor 22 as a pair. Although configured, the high-side MOSFET 2H and the low-side MOSFET 2L may be configured separately and a bridge circuit may be configured by the four semiconductor switching elements 2.
Alternatively, a configuration may be adopted in which a bridge circuit is configured with six semiconductor switching elements 2 to drive and control a three-phase brushless motor.
Further, although the power device is the semiconductor switching element 2, other power devices such as a diode and a thyristor may be used.

Moreover, although the said embodiment demonstrated the example applied to the electric power steering apparatus of the motor vehicle, it equipped with power devices, such as an electronic controller of an anti-lock brake system (ABS), and an electronic controller related to an air conditioning. The present invention is also applicable to an electronic control device that handles a large current (for example, 25 A or more).
In addition, the dimension, shape, and number of each component mentioned above are examples, and of course, it is not limited to this size, shape, and number.

  DESCRIPTION OF SYMBOLS 1 Electronic control apparatus, 2 Semiconductor switching element (power device), 3 Housing, 3a Insulating resin, 3b Holding part, 3c Opening inner wall surface, 3d Positioning part, 3e Positioning part, 4 Circuit board, 5 Heat sink, 5a End surface, 5b Anodized surface, 5c Heat radiation fin, 6a Power conductive plate, 6b Output conductive plate, 6c Signal conductive plate, 6d Conductive plate, 6e Conductive plate, 6f Holding member, 6ap to 6fp Press-fit terminal, 7 Cover, Vehicle connector , 9 Motor connector, 10 Sensor connector, 11 Power connector terminal, 12 Signal connector terminal, 13 Motor connector terminal, 14 Sensor connector terminal, 20 Screw, 21 Leaf spring, 21a Holding part, 21b Locking part, 21s Slit part, 22 Electric motor, 23 torque sensor, 2 Battery, 41 Microcomputer (low current component), 42 Power supply IC (low current component), 43 Driver IC (low current component), 44 Coil (high current component), 45 Capacitor (high current component), 46 Relay (High current) Parts), 47 shunt resistance (high current parts), 51 heat sink body, 52 anodized film.

Claims (19)

A housing made of an insulating resin having an opening at each end on both sides;
A heat sink in which a plurality of connectors are attached to one end of the housing distributed on the side surface, and a power device is mounted on the surface on the housing side,
A circuit board provided opposite to the heat sink,
The power device is disposed in the vicinity of a connector terminal in one of the plurality of connectors electrically connected to the power device,
The circuit board includes a plurality of small current components including a microcomputer that controls driving of the power device on one surface, and a capacitor that absorbs a ripple of current flowing through the power device on the other surface. High current parts are mounted,
The electronic control apparatus according to claim 1, wherein all of the high-current components are arranged at a peripheral edge portion of the circuit board and at a position not overlapping the power device. A housing made of an insulating resin having an opening at each end on both sides;
A heat sink in which a plurality of connectors are attached to one end of the housing distributed on the side surface, and a power device is mounted on the housing side surface;
A circuit board provided opposite to the heat sink,
The power device is disposed in the vicinity of a connector terminal in one of the plurality of connectors electrically connected to the power device,
The circuit board is mounted with a plurality of small current components including a microcomputer for controlling the drive of the power device on one surface, and a plurality of large current resistors including a shunt resistor for detecting a current flowing through the power device on the other surface. Current components are mounted,
The electronic control apparatus according to claim 1, wherein all of the high-current components are arranged at a peripheral edge portion of the circuit board and at a position not overlapping the power device.   3. The electronic control device according to claim 1, wherein the small-current component is mounted on a surface of the circuit board opposite to a surface facing the power device. 4.   4. The coil according to claim 1, wherein a coil that prevents electromagnetic noise generated when the power device is driven from flowing out to the outside is mounted on the other surface of the circuit board. 5. The electronic control device described.   5. The electronic control device according to claim 1, wherein a relay that opens and closes a current flowing through the power device is mounted on the other surface of the circuit board.   The electronic control device according to claim 1, wherein the high-current component is disposed at a corner of the circuit board.   2. The electronic control device according to claim 1, wherein a shunt resistor for detecting a current flowing through the power device is mounted on the other surface of the circuit board in proximity to the capacitor.   The heat sink is formed with a film for increasing thermal emissivity on at least one of a front surface on which the power device is mounted and a rear surface thereof. Electronic control unit.   The electronic control device according to claim 8, wherein an exposed end surface of the heat sink that does not have the coating is in surface contact with an inner wall surface of the housing.   The electronic control device according to claim 8, wherein the coating is an alumite coating.   11. The electronic control device according to claim 1, wherein a radiation fin is formed on a surface of the heat sink opposite to a surface on which the power device is mounted.   The electronic control device according to any one of claims 1 to 11, wherein the heat sink has a heat sink body made of aluminum or an aluminum alloy.   The electronic control apparatus according to any one of claims 8 to 11, wherein the power device is fixed to a surface of the film via a heat conductive adhesive.   The electronic control apparatus according to claim 1, wherein the power device is pressed against the heat sink by a leaf spring.   The electronic control device according to claim 14, wherein the leaf spring is locked to the housing, and is fixed to the heat sink with a screw through the housing. A cover is attached to the other end of the housing, and a housing is constituted by the housing, the heat sink and the cover.
The at least one current component out of the large current component and the small current component in the casing is in contact with the inner wall surface of the housing via an inclusion having thermal conductivity. The electronic control device according to any one of -15.   The electronic control device according to claim 16, wherein the inclusion is a gel or an elastic material.   The electronic control apparatus according to claim 1, wherein the power device is a semiconductor switching element.   The electronic control device according to claim 1, wherein the electronic control device is an electric power steering device.

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