JP6331424B2 - Electronic control unit and electric power steering device - Google Patents

Description

  The present invention relates to an electronic control unit and an electric power steering apparatus including the same.

  The electric power steering apparatus includes an electronic control unit (ECU) that controls driving of the electric motor based on detection signals of various sensors such as a torque sensor. The electronic control unit includes a circuit board on which a power semiconductor element (for example, MOSFET) is mounted, a housing that houses the circuit board, and the like. However, the power semiconductor element generates heat at a high temperature when energized. It is necessary to take heat countermeasures to dissipate the heat generated from the element to the outside of the housing.

  As a method for dissipating the heat generated by the heating element to the outside, for example, there is a technique described in Patent Document 1. This technology dissipates the heat of the heating element to the outside by a heat sink. Between the circuit board on which the heating element is mounted and the heat sink, an electrical insulating layer and a heat transfer metal formed thereon are provided. A heat transfer substrate having a foil layer is interposed. Here, the circuit board and the metal foil layer of the heat transfer board are joined by solder.

  As another method, for example, there is a technique described in Patent Document 2. In this technology, a heat sink is closely attached to the side opposite to the heating element mounting portion of the circuit board and the side opposite to the circuit board of the heating element, and the heat of the heating element is transferred to the board surface side and the opposite side of the heating element. The heat is dissipated from both sides.

JP 2011-165867 A JP 2010-245174 A

However, the technique described in Patent Document 1 requires a heat transfer board interposed between the circuit board and the heat sink, resulting in an increase in the number of components. Furthermore, since the heat transfer board is joined to the circuit board by soldering, the number of assembly steps increases.
Moreover, in the technique of the said patent document 2, although it is the structure which closely_contact | adheres a heat sink to a circuit board, when a circuit board warps, adhesive force will change and heat dissipation will deteriorate.
Therefore, an object of the present invention is to provide an electronic control unit that can effectively dissipate the heat of the heating element without increasing the number of components, and an electric power steering apparatus including the electronic control unit.

In order to solve the above problems, one aspect of an electronic control unit according to the present invention includes a circuit board on which an electronic component including a heating element is surface-mounted, a metal base, and a metal cover, A housing for holding the circuit board by sandwiching and fixing the peripheral edge of the circuit board in the thickness direction, and at least one of the base and the cover is interposed between the heat conductive member and the insulating member. includes a heat radiating portion 1 to come in contact, via the heat-conductive member in a position facing each other across the circuit board with respect to the heating element, and a heat radiating portion 2 that come in contact to the circuit board, at least the the locations radiating unit 2 is in contact, comprises a metallic foil layer, the insulation layer formed in a pattern such that a portion of the metal foil layer are exposed.

In this way, the heat radiating portion is formed in the housing, and the heat is radiated from the heat generating element by bringing it into close contact with the surface of the heat generating element or the circuit board opposite to the heat generating element mounting portion. At this time, heat dissipation can be ensured by providing a thermally conductive member between the heat generating element and the heat radiating portion 1 and between the circuit board and the heat radiating portion 2. An insulating layer is formed on the heat dissipation surface directly facing the FET 31 of the heat dissipation portion 1. As for the heat radiating portion 2, a substrate insulating layer is formed on the metal foil layer on the surface of the circuit board, and the substrate insulating layer is formed in a pattern shape in which a part of the metal foil surface is exposed. Thereby, a heat conductive member and a metal foil layer can be in direct contact, and heat dissipation can be ensured. Further, since it is possible to prevent the housing and the metal foil surface of the circuit board from coming into direct contact, the formation of an insulating layer on the housing can be omitted.
Furthermore, the warp of the circuit board is corrected by the correction portion formed in the housing, and unevenness in the close contact between the heating element and the heat conductive member is prevented. Thereby, heat dissipation can be stabilized.

In the above, absolute Enso is preferably formed in a lattice shape. Thereby, even when the base or the cover is bent in the heat radiating portion 2, it is possible to prevent contact with the metal foil surface.

  Moreover, in the above, it is desirable that the base and the cover include a correction portion that presses the circuit board in the thickness direction so as to correct the warp of the circuit board. Thereby, the curvature which arose in the circuit board is corrected, it can prevent that nonuniformity arises in contact | adherence with a heat generating element and a heat conductive member, and can stabilize heat dissipation.

Moreover, in the above, it is preferable to provide an elastic member between the circuit board and the correction part. Thereby, a circuit board can be appropriately pressed by the correction part, and the curvature of a circuit board can be corrected effectively.
Furthermore, in the above, it is preferable that the elastic member includes a heat conductive material. As a result, the elastic member between the circuit board and the correction portion can have a heat dissipation function.

  Moreover, in the above, it is preferable that the heat conductive member includes an insulating material. Thereby, the heat conductive member between the heat generating element and the circuit board and the heat radiating portion can be provided with an insulating function.

  According to another aspect of the present invention, there is provided an electric power steering apparatus that includes a torque detection unit that detects a steering torque transmitted from a steering wheel, and an electric motor that generates a steering assist torque according to the steering torque detected by the torque detection unit. A motor, and any one of the electronic control units that controls driving of the electric motor. As described above, since the electronic control unit having both heat dissipation and insulation properties is provided, the electric motor can be stably operated, and appropriate steering assist control can be performed.

  In the electronic control unit of the present invention, since the heat radiating portion and the correction portion are formed in the housing that houses the circuit board on which the heating element is mounted, the warp of the circuit board is corrected effectively without increasing the number of components. Heat generated by the heating element can be dissipated. In addition, since the insulating layer is provided between the heat generating element and the circuit board and the heat radiating portion, and between the circuit board and the correction portion, it is possible to ensure insulation in addition to the heat radiating property. Furthermore, since the insulating layer with the metal foil surface exposed is provided on the surface of the circuit board, insulation can be ensured without providing an insulating layer on the housing.

It is a figure which shows the basic structure of the electric power steering apparatus by which the electronic control unit of this embodiment is mounted. It is a figure which shows the structure of a controller. It is a disassembled perspective view of an electronic control unit. It is a disassembled perspective view of an electronic control unit. It is a figure which shows the assembly state of an electronic control unit. It is a figure which shows sectional drawing of an electronic control unit. It is sectional drawing of a thermal radiation part. It is sectional drawing of a correction part. It is sectional drawing which shows another example of a correction part. It is a figure which shows another example of an elastic member.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a basic structure of an electric power steering apparatus on which the electronic control unit of this embodiment is mounted.
In the figure, reference numeral 1 denotes a steering wheel, and the steering force applied to the steering wheel 1 from the driver is transmitted to the steering shaft 2. The steering force transmitted to the steering wheel 1 is transmitted to the tie rod 6 via the reduction gear 3, the universal joints 4A and 4B, and the pinion rack mechanism 5, and steers steered wheels (not shown).

The steering shaft 2 is provided with a torque sensor 7 that detects a steering torque Ts that is applied to the steering wheel 1 and transmitted to the steering shaft 2. The reduction gear 3 is connected to an electric motor 8 that generates a steering assist force for the steering system. Here, the electric motor 8 is a three-phase brushless motor.
Electric power is supplied to the controller 10 from a battery (not shown), and an ignition key signal IGN (see FIG. 2) is input via an ignition key (not shown). The controller 10 calculates a steering assist command value based on the steering torque Ts detected by the torque sensor 7 and the vehicle speed V detected by the vehicle speed sensor 9, and supplies the steering assist command value to the electric motor 8 based on the calculated steering assist command value. Control the current.

The controller 10 is mainly composed of a microcomputer, and its configuration is as shown in FIG. The controller 10 includes a control arithmetic device 11, a gate drive circuit 12, a motor drive unit 13, and a cutoff device 14.
In addition to the steering torque Ts and the vehicle speed V, the control arithmetic unit 11 calculates the three-phase motor currents ia to ic detected by the current detection circuit 15 and the rotational position θ of the electric motor 8 detected by the rotor position detection circuit 17. Based on these, the current command value of the electric motor 8 is calculated based on these. The control arithmetic device 11 outputs the calculated current command value to the gate drive circuit 12.

Here, a rotation sensor 16 such as a Hall sensor is attached to the electric motor 8, and the rotor position detection circuit 17 detects the rotation position θ based on the rotation signal RT from the rotation sensor 16. Yes.
The ignition signal IGN from the ignition key is input to the ignition voltage monitor unit 18 and the power supply circuit unit 19, and the power supply voltage Vdd and the reset signal RS for stopping the device are input from the power supply circuit unit 19 to the control arithmetic unit 11. It has come to be.

  The gate drive circuit 12 forms a gate drive signal based on the input current command value and the like, and outputs it to the motor drive unit 13 having a FET bridge configuration. The motor drive unit 13 is an inverter circuit including FETs Tr1 to Tr6 that are power semiconductor elements. The motor drive unit 13 drives the electric motor 8 via an emergency stop interrupting device 14. Here, the interruption | blocking apparatus 14 is comprised by the relay contacts 141 and 142 which interrupt | block two phases.

Here, the breaking device 14 is configured to use a contact-type relay, but a semiconductor-type relay can be used instead. In this case, a semiconductor relay is inserted in each phase of the electric motor 8.
3 and 4 are exploded perspective views of an electronic control unit (ECU) constituting the controller 10.

The electronic control unit 20 includes a circuit board 30 on which FETs Tr1 to Tr6 and the like constituting the motor drive unit 13 are mounted, and an ECU housing (ECU base 40 and plate (cover) 50) that accommodates the circuit board 30.
The circuit board 30 is made of resin with FR-4 or the like as a base material, and a FET 31 that is a heating element is mounted on the surface of the circuit board 30 by solder. Here, the FET 31 is a FET Tr1 to Tr6 for driving a motor, a relay FET when a semiconductor relay is used as the interrupting device 14, or the like.

  Further, an elastic member 32 is fixed to a portion of the circuit board 30 where the FET 31 is not mounted by an adhesive member such as a bond or a double-sided tape. The elastic member 32 is fixed to both sides of the circuit board 30 at positions facing each other with the circuit board 30 interposed therebetween. Furthermore, a plurality of through holes 33 into which mounting screws 60 (see FIG. 5) for attaching the circuit board 30 to the ECU base 40 are screwed are formed in the peripheral portion of the circuit board 30.

The ECU base 40 is a box-shaped member having an opening, and the circuit board 30 can be attached to the opening. The ECU base 40 is formed by, for example, aluminum die casting.
At the bottom of the ECU base 40, a first heat radiating portion 41 protruding toward the circuit board 30 is formed at a position directly facing the FET 31 with the circuit board 30 attached. Further, a second heat radiating portion 42 that protrudes toward the circuit board 30 is formed at a position facing the FET 31 via the circuit board 30. Each of the first heat radiating portion 41 and the second heat radiating portion 42 includes heat radiating surfaces 41 a and 42 a that are planes parallel to the circuit board 30 at the end on the circuit board 30 side.

In addition, a correction portion 43 that protrudes toward the opening is formed at the bottom of the ECU base 40 at a position facing the elastic member 32 with the circuit board 30 attached. The correction portion 43 includes a correction surface 43 a that is a plane parallel to the circuit board 30 at the end on the circuit board 30 side.
An insulating layer is formed on the heat radiation surface 41a directly facing the FET 31. In addition, an insulating layer is formed on the surface of the circuit board 30 where the second heat radiating surface 42a and the correction surface 43a are opposed to each other. For the insulating layer, a solder resist formed to insulate the surface of the circuit board 30 is used.

Further, a screw hole 44 into which the mounting screw 60 is screwed is formed at a peripheral portion of the ECU base 40 at a position corresponding to the through hole 33 of the circuit board 30.
The plate 50 is a plate-like metallic member that is fixed to the ECU base 40 so as to close the opening of the ECU base 40. On the plate 50, a first heat radiating portion 51 that protrudes toward the circuit board 30 is provided via the FET 31 and the circuit board 30 at a position directly facing the FET 31 while being fixed to the ECU base 40 to which the circuit board 30 is attached. A second heat dissipating part 52 that protrudes toward the circuit board 30 is formed at a position facing each other. Each of the first heat radiating part 51 and the second heat radiating part 52 includes heat radiating surfaces 51 a and 52 a, which are flat surfaces parallel to the circuit board 30, at the end on the circuit board 30 side.

The plate 50 is formed with a correction portion 53 that protrudes toward the circuit board 30 at a position facing the elastic member 32 while being fixed to the ECU base 40 to which the circuit board 30 is attached. The correction portion 53 includes a correction surface 53 a that is a plane parallel to the circuit board 30 at the end on the circuit board 30 side.
An insulating layer is formed on the heat dissipating surface 51 a directly facing the FET 31. The insulating layer is formed by alumite treatment or fluorine coating.
In addition, an insulating layer is formed on the surface of the circuit board 30 at locations facing the heat radiating surface 52a and the correction surface 53a, respectively. The insulating layer is formed using a solder resist used for insulating the circuit board surface.

  An insulating layer 30b is formed on the circuit board 30 at a location facing the second heat radiating portion 42 of the ECU base 40 and the second heat radiating portion 52 of the plate 50, and a copper foil layer 30a for assisting heat radiation. The insulating layer 30b is formed in a substantially mesh shape so that a part of the copper foil layer 30a is periodically exposed.

A through hole 54 into which the mounting screw 60 is screwed is formed at a peripheral portion of the plate 50 at a position corresponding to the screw hole 44 of the ECU base 40.
Then, the electronic control unit 20 is completed by attaching the plate 50 from above the circuit board 30 to the ECU base 40 to which the circuit board 30 is attached, and fixing with the attachment screw 60 as shown in FIG.

6A and 6B are views showing the assembled state of the electronic control unit 20, wherein FIG. 6A is a front view, FIG. 6B is an AA cross-sectional view, and FIG. 6C is a BB cross-sectional view.
In the assembled state of the electronic control unit 20, as shown in FIG. 6B, the FET 31 mounted on the circuit board 30 has the heat radiation surfaces 41 a and 41 b formed on the ECU base 40 and the heat radiation formed on the plate 50. The surfaces 51 a and 52 b are sandwiched from both sides in the thickness direction of the circuit board 30. At this time, a grease-like or sheet-like thermally conductive material (TIM) is interposed between the FET 31 and the heat dissipation part 41 and between the FET 31 and the heat dissipation part 51, respectively.

That is, when the FET 31 is mounted on the upper surface of the circuit board 30 (the surface on the ECU base 40 side), as shown in FIG. The heat radiating surface 41a on which the insulating layer 41b is formed is brought into close contact with the TIM 34. Further, a heat radiating surface 52a is brought into close contact with the surface of the circuit board 30 opposite to the FET 31 via the TIM 34.
At this time, since the insulating layer 30b formed on the circuit board 30 is formed so that a part of the copper foil layer 30a is exposed, the TIM 34 is in direct contact with the copper foil layer 30a and the heat dissipation surface 52a. Heat is transferred from the copper foil layer 30a to the heat radiating surface 52a, and the insulating layer 30b prevents the copper foil layer 30a and the heat radiating surface 52a from contacting each other. In this embodiment, as shown in FIG. 7B, the insulating layer 30b is formed in a lattice shape on the copper foil layer 30a formed on the circuit board 30. As a result, the portion of the copper foil layer 30a that is not covered by the insulating layer 30b can be brought into direct contact with the TIM 34, and the heat dissipation surface 52a can be prevented from coming into direct contact with the surface of the copper foil layer 30a. .

  The material of the insulating layer 30b preferably includes an epoxy resin having excellent insulating properties. The thickness of the insulating layer 30b is preferably formed in the range of 10 to 40 μm, and more preferably in the range of 16 to 30 μm. If the thickness of the insulating layer 30b is less than 10 μm, the insulation between the copper foil layer 30a and the heat radiation parts 42 and 52 may not be maintained, which is not preferable. Moreover, when it is thicker than 40 μm, in particular, when the TIM 34 is formed into a sheet shape, the adhesiveness with the copper foil layer 30a may be deteriorated and heat dissipation may be deteriorated, which is not preferable.

Further, as shown in FIG. 6C, a portion where the FET 31 is not mounted on the circuit board 30 is an elastic member by a correction surface 43 a formed on the ECU base 40 and a correction surface 53 a formed on the plate 50. The circuit board 30 is sandwiched from both sides in the thickness direction via 32.
That is, as shown in the enlarged view of the β portion of FIG. 6C in FIG. 8, the elastic member 32 is fixed to the upper surface of the circuit board 30 (the surface on the ECU base 40 side) by the adhesive member 32a. The substrate 30 is pressed downward (plate 50 side) by the correction surface 43a on which the insulating layer 43b is formed via the elastic member 32.

Similarly, the elastic member 32a is attached to the lower surface (the surface on the plate 50 side) of the circuit board 30 at a position facing the elastic member 32 fixed to the upper surface of the circuit board 30 with the circuit board 30 interposed therebetween. 32 is fixed, and the circuit board 30 is pressed upward (to the ECU base 40 side) by the correction surface 53a on which the insulating layer 53b is formed via the elastic member 32.
Here, the pressing force of the correction portions 43 and 53 against the circuit board 30 is set to such an extent that the warp of the circuit board 30 is corrected.

  As described above, a part of the peripheral edge of the circuit board 30 is sandwiched in the thickness direction by the ECU base 40 and the plate 50 constituting the ECU housing, and is fixed by the mounting screw 60. At this time, the heat radiation portions 41 and 42 of the ECU base 40 and the heat radiation portions 51 and 52 of the plate 50 sandwich the FET 31 and the circuit board 30 via the TIM 34 so that the heat of the FET 31 is radiated from both surfaces of the circuit board 30. To.

  That is, for example, as shown in FIG. 7, when the FET 31 is mounted on the upper surface of the circuit board 30 (the surface on the ECU base 40 side), the heat radiation portion 41 formed on the ECU base 40 is formed on the upper surface of the FET 31. The heat radiating surface 41 a is brought into close contact with the TIM 34. Thereby, the heat of the FET 31 can be released from the upper surface of the FET 31 to the ECU base 40 via the TIM 34.

At the same time, the heat radiation surface 52 a of the heat radiation portion 52 formed on the plate 50 is brought into close contact with the lower surface of the FET 31 (the surface opposite to the FET 31 mounting portion of the circuit board 30) via the TIM 34. As a result, heat from the FET 31 can be released from the lower surface of the circuit board 30 to the plate 50 via the TIM 34 simultaneously with heat radiation from the upper surface of the FET 31.
Thus, the heat of the FET 31 can be efficiently radiated from both sides of the FET 31.

Further, since the heat radiating portions 41, 42, 51, and 52 are formed in the ECU housing (ECU base 40 and the plate 50) that accommodates the circuit board 30, there is no need to newly add heat radiating parts, and the configuration of the electronic control unit 20 An increase in parts can be prevented. Furthermore, since no solder joint or the like is required when realizing the heat dissipation mechanism, the number of assembly steps can be reduced.
In addition, an insulating layer 30b is formed on the circuit board 30 where the heat radiating portion 42 of the ECU base 40 and the heat radiating portion 52 of the plate 50 face each other so that the copper foil layer 30a is partially exposed on the copper foil layer 30a. Therefore, the copper foil layer 30a efficiently conducts heat, and the insulating layer 30b prevents the copper foil layer 30a and the heat radiating portions 42 and 52 from contacting each other, thereby preventing an electrical short circuit and maintaining the operation. .

  By the way, when it is the structure which heat-dissipates by closely_contact | adhering heat dissipation surface 41a, 42a, 51a, 52a via TIM34 to the circuit board 30 with which FET31 and FET31 were mounted like this embodiment, it warps the circuit board 30. When this occurs, the gaps between the FET 31 and the circuit board 30 and the heat radiation surfaces 41a, 42a, 51a, and 52a vary, and the adhesion between the FET 31 and the circuit board 30 and the heat radiation parts 41 and 51 changes.

If the TIM 34 interposed between the FET 31 and the ECU base 40 and between the FET 31 and the plate 50 is too thick, the heat transfer effect cannot be exhibited, and the heat dissipation is deteriorated. On the other hand, if the thickness of the TIM 34 is too thin, the insulating properties deteriorate.
Therefore, it is necessary to manage the intervals between the FET 31 and the ECU base 40 and between the FET 31 and the plate 50 within appropriate ranges.

  Therefore, in the present embodiment, the ECU base 40 and the plate 50 are provided with the correction portions 43 and 53 facing each other with the circuit board 30 interposed therebetween, and the portions where the FET 31 of the circuit board 30 is not mounted by the correction portions 43 and 53. The warp of the circuit board 30 is corrected by pressing from both sides in the thickness direction. As a result, the thickness of the TIM 34 can be controlled to a predetermined thickness, unevenness in the close contact between the FET 31 and the circuit board 30 and the TIM 34 can be prevented, and stable heat dissipation can be realized. it can. At this time, since the correction portions 43 and 53 are disposed to face each other with the circuit board 30 interposed therebetween, the warp of the circuit board 30 can be corrected appropriately.

  As described above, in this embodiment, by providing a correction mechanism that corrects the warp of the circuit board 30, the FET 31 and the circuit board 30 are sandwiched between the ECU base 40 and the plate 50, and heat is radiated from both sides of the FET 31. In the structure, the heat of the FET 31 can be released efficiently and stably. Further, since the insulating layer is formed on the ECU base 40 and the plate 50 on the side facing the circuit board 30, both heat dissipation and insulating properties can be achieved.

(Modification)
In the above embodiment, as a correction mechanism for correcting the warp of the circuit board 30, the circuit board 30 is sandwiched between the ECU base 40 (correction unit 43) and the plate 50 (correction unit 53) via the elastic member 32. As described above, as shown in FIG. 9, the circuit board 30 may be directly sandwiched between the ECU base 40 (correction unit 43) and the plate 50 (correction unit 53). Thereby, the correction mechanism of the circuit board 30 can be realized without adding the elastic member 32.

  Moreover, in the said embodiment, as shown to FIG.3 and FIG.4, although the case where the cross-sectional shape of the elastic member 32 was made circular was demonstrated, as shown to Fig.10 (a), a square may be sufficient. However, it may have a shape having a hole at the center. The elastic member 32 and the ECU base 40 or the plate 50 may have a fitting structure as shown in FIG. Further, the elastic member 32 may be a metal or metal + resin member, and may be fixed to the circuit board 30 by surface mounting.

Furthermore, in the said embodiment, although the correction surfaces 43a and 53a were formed in the correction | amendment parts 43 and 53 and the case where the curvature of the circuit board 30 was corrected by surface contact was demonstrated, point contact and line contact may be sufficient. .
Moreover, in the said embodiment, the elastic member 32 can be made into the elastic member (elastic TIM) containing a heat conductive material, and can also have a heat dissipation function.
In this case, an insulating layer is formed on the circuit board 30 where the correction parts 43 and 53 are in contact with each other as in the case of the heat radiation parts 42 and 52, and the insulating layers of the correction surfaces 43a and 53a are omitted. Also good.

  Furthermore, in the above embodiment, the case where the ECU base 40 and the insulating layer of the plate 50 are formed on the heat dissipation surfaces 41a, 42a, 51a, 52a and the correction surfaces 43a, 53a on the circuit board 30 has been described. An insulating auxiliary material may be added to the TIM 34 as a heat conductive material interposed between the circuit board 30 and the heat radiation part 51 and between the heat radiation part 41 and the heat radiation part 41. Thereby, heat dissipation and insulation can be realized more effectively, and formation of an insulating layer on the ECU base 40 and the plate 50 can be omitted.

Further, in the above-described embodiment, the case where the correction unit 43 of the ECU base 40 and the correction unit 53 of the plate 50 are disposed to face each other with the circuit board 30 interposed therebetween is described. Not necessarily.
Moreover, in the said embodiment, although the case where the thermal radiation part 41,42,51,52 was formed in both ECU base 40 and the plate 50 was demonstrated, any one may be sufficient.

  Further, in the above embodiment, the description has been given of the form in which the insulating layer 30b of the circuit board 30 with which the heat radiation portions 42 and 52 are in contact is formed in a lattice shape, and a part of the copper foil layer 30a is exposed. As long as the copper foil layer 30a is in direct contact with the copper foil layer 30a and the copper foil layer 30a is not in contact with the heat dissipation surface (42a, 52a). For example, the lattice crossing angle of the insulating layer 30b may not be 90 degrees. Further, the insulating layer 30b may be formed so as to expose the copper foil layer 30a from the circular shapes arranged periodically.

DESCRIPTION OF SYMBOLS 1 ... Steering wheel, 2 ... Steering shaft, 3 ... Reduction gear, 4A, 4B ... Universal joint, 5 ... Pinion rack mechanism, 6 ... Tight rod, 7 ... Torque sensor, 8 ... Electric motor, 9 ... Vehicle speed sensor, 10 ... Controller 11 control controller 12 gate drive circuit 13 motor drive unit 14 interrupting device 15 current detection circuit 16 rotation sensor 17 rotor position detection circuit 18 IGN voltage monitor unit DESCRIPTION OF SYMBOLS 19 ... Power supply circuit part, 20 ... Electronic control unit, 30 ... Circuit board, 30a ... Copper foil layer, 30b ... Insulating layer (substrate insulating layer), 31 ... FET, 32 ... Elastic member, 33 ... Through-hole, 34 ... TIM 40 ... ECU base, 41 ... heat radiating part (heat radiating part 1), 41a ... heat radiating surface, 41b ... insulating layer, 42 ... heat radiating part (heat radiating part 2), 42a ... heat radiating surface, 4 ... Straightening part, 43a ... Straightening surface, 43b ... Insulating layer, 44 ... Screw hole, 50 ... Plate, 51 ... Heat radiation part (heat radiation part 1), 51a ... Heat radiation surface, 51b ... Insulating layer, 52 ... Heat radiation part (heat radiation part) 2), 52a ... radiation surface, 53 ... correction part, 53a ... correction surface, 54 ... through hole, 60 ... mounting screw

Claims (7)

A circuit board on which electronic components including heating elements are surface-mounted,
A housing made of a metal base and a metal cover, and holding the circuit board by sandwiching and fixing the peripheral edge of the circuit board in the thickness direction,
The base and at least one of the cover via the heat conductive member and the insulating member, and the heat radiating portion 1 to come in contact to the heating element, heat at positions facing each other across the circuit board with respect to the heating elements through the conductive member, and a heat radiating portion 2 which come in contact,
The circuit board has an electronic layer having a metal foil layer and an insulating layer formed in a pattern so that a part of the metal foil layer is exposed at least at a location where the heat dissipating part 2 contacts. unit. The electronic control unit according to claim 1, pattern before Kize' edge layer, characterized in that it is formed in a lattice shape. The base and cover, so as to correct the warp of the circuit board, the circuit board, to claim 1 or claim 2, characterized in that it comprises a correction unit for pressing in the thickness direction via the insulating layer Electronic control unit as described.   The electronic control unit according to claim 3, further comprising an elastic member between the circuit board and the correction unit.   The electronic control unit according to claim 4, wherein the elastic member includes a heat conductive material.   The electronic control unit according to claim 1, wherein the heat conductive member includes an insulating material. A torque detector for detecting a steering torque transmitted from the steering wheel;
An electric motor that generates a steering assist torque according to the steering torque detected by the torque detector;
An electric power steering apparatus characterized by comprising an electronic control unit according to any one of 請 Motomeko 1-6 that controls the driving of the electric motor.

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