JP2018125948A - Electric driving device and electric power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel electric driving device having excellent heat radiation characteristics while reducing the appearance shape in size, the weight, and a number of components, and an electric power steering device.SOLUTION: An electric driving device comprises: the prescribed number of screw stopper concave parts 38 that is concaved in an inner radial direction side formed on an outer peripheral surface of an end surface part of an aluminum type metal motor housing 11 on the side opposite to an output part of a rotational axis of an electric motor; and a screw stopper convex part 39 that is projected to the inner radial direction side housed in the screw stopper concave part formed in the outer peripheral surface of a metal cover 12 covering an electronic control part that controls the electric motor. The screw stopper convex part 39 is fixed to the screw stopper concave part 38 with a metal fixing screw 37 toward an inner side from a radial direction while housing the screw stopper convex part 39 in the screw stopper concave part 38 in a state where a head part 37H of the fixing screw 37 is not projected from an external surface of the metal cover 12.SELECTED DRAWING: Figure 11

Description

  The present invention relates to an electric drive device and an electric power steering device, and more particularly to an electric drive device and an electric power steering device incorporating an electronic control device.

  In the general industrial machinery field, a mechanical control element is driven by an electric motor. Recently, an electronic control unit including a semiconductor element or the like for controlling the rotational speed or rotational torque of the electric motor is electrically driven. A so-called electromechanical integrated electric drive device that is integrated into a motor is beginning to be adopted.

  As an example of an electromechanical integrated electric drive device, for example, in an electric power steering device of an automobile, a rotation direction and a rotation torque of a steering shaft that is rotated by a driver operating a steering wheel are detected. The electric motor is driven to rotate in the same direction as the rotation direction of the steering shaft based on the detected value, and the steering assist torque is generated. In order to control this electric motor, an electronic control unit (ECU: Electronic Control Unit) is provided in the power steering apparatus.

  As a conventional electric power steering device, for example, a device described in JP-A-2015-134598 (Patent Document 1) is known. Patent Literature 1 describes an electric power steering device that includes an electric motor unit and an electronic control unit. The electric motor of the electric motor unit is housed in a motor housing having a cylindrical part made of aluminum alloy or the like, and the board on which the electronic components of the electronic control unit are mounted is the output shaft in the axial direction of the motor housing. It is attached to a heat sink that functions as an ECU housing arranged on the opposite side. The substrate attached to the heat sink includes a power supply circuit unit, a power conversion circuit unit having a power switching element such as a MOSFET or IGBT for driving and controlling the electric motor, and a control circuit unit for controlling the power switching element, and power switching. The output terminal of the element and the input terminal of the electric motor are electrically connected via a bus bar.

  The electronic control unit attached to the heat sink is supplied with electric power from a power source via a connector case made of synthetic resin, and detection signals such as an operation state are supplied from detection sensors. The connector case functions as a lid, is fixed so as to seal and close the heat sink, and is fixed to the outer peripheral surface of the heat sink by a fixing screw.

  In addition, as an electric drive device integrated with an electronic control device, an electric brake, an electric hydraulic controller for various hydraulic controls, and the like are known. However, in the following explanation, an electric power steering device is representative. explain.

JP2015-134598A

  By the way, in the electric power steering apparatus having the configuration as disclosed in Patent Document 1, the metal motor housing, the metal heat sink, and the synthetic resin connector case are fixed by inserting a fixing portion that protrudes to the outer peripheral side. It is a structure that is fastened together with screws.

  However, when the fixing portion and the fixing screw are provided on the outer periphery of the motor housing, the heat sink, and the connector case, there arises a problem that the external shape becomes large and the weight increases. Furthermore, the motor housing and heat sink are in close contact with each other, but the close contact portion has a large thermal resistance and cannot perform good heat transfer, resulting in poor heat dissipation. Therefore, the problem that the connector case does not contribute to heat radiation and the heat radiation characteristics are not good also arises. Therefore, there is a demand for an electric drive device and an electric power steering device that solve these problems.

  Furthermore, in the electric power steering apparatus having a configuration as described in Patent Document 1, which is a subsidiary, a heat sink member for radiating heat of the power supply circuit unit and the power conversion circuit unit to the outside is particularly provided with the motor housing. Arranged between the ECU housings. For this reason, the length in the axial direction tends to be longer by the amount of the heat sink member. In addition, the electrical components that constitute the power supply circuit unit and the power conversion circuit unit generate a large amount of heat, and it is necessary to efficiently dissipate this heat to the outside when downsizing. Therefore, it is also required to reduce the axial length as much as possible and to efficiently dissipate the heat of the power supply circuit unit and the power conversion circuit unit to the outside.

  SUMMARY OF THE INVENTION The main object of the present invention is to provide a novel electric drive device and electric power steering device having a reduced external shape to reduce weight and having good heat dissipation characteristics.

  A feature of the present invention is that a predetermined number of fixed recesses recessed inward in the radial direction formed on the outer peripheral surface of the end surface portion of the aluminum-based metal motor housing opposite to the output portion of the rotating shaft of the electric motor, and the electric motor A fixed convex portion that is formed at the opening end of the metal cover that covers the electronic control unit that controls the projection and that protrudes inward in the radial direction and is accommodated in the fixed concave portion. The fixing convex portion is fixed to the fixing concave portion by the metal fixing means so that the head of the fixing means does not protrude from the outer surface of the metal cover.

  According to the present invention, the fixing convex portion formed at the opening end of the metal cover is accommodated in the fixing concave portion formed on the outer peripheral surface of the motor housing, and is fixed by the metal fixing means from the radial direction to the inside. Since the fixing convex portion of the metal cover is fixed to the fixing concave portion of the motor housing in a state where the head of the means does not protrude from the outer surface of the metal cover, the external shape can be reduced and the weight can be reduced. Moreover, since it fixes by metal fixing means, the heat from a motor housing is transmitted to a metal cover via a fixing means, Therefore A heat dissipation characteristic can be improved.

1 is an overall perspective view of a steering apparatus as an example to which the present invention is applied. 1 is an overall perspective view showing an overall shape of an electric power steering apparatus according to an embodiment of the present invention before sealing with an adhesive. FIG. 3 is an exploded perspective view of the electric power steering device shown in FIG. 2. It is a perspective view of the motor housing shown in FIG. FIG. 5 is a cross-sectional view of the motor housing shown in FIG. 4 taken along the axial direction. It is a perspective view which shows the state which mounted and fixed the power conversion circuit part in the motor housing shown in FIG. It is a perspective view which shows the state which mounted and fixed the power supply circuit part to the motor housing shown in FIG. It is a perspective view which shows the state which mounted and fixed the control circuit part in the motor housing shown in FIG. It is a perspective view which shows the state which mounted and fixed the connector terminal assembly to the motor housing shown in FIG. It is a front view of the electric power steering device before performing sealing with an adhesive. FIG. 11 is a cross-sectional view of the electric power steering apparatus shown in FIG. 10 and after sealing with an adhesive. It is a fragmentary sectional view which shows the axial cross section before sealing with an adhesive agent in the junction part vicinity of a motor housing and a metal cover. It is a fragmentary sectional view which shows the axial cross section after sealing with the adhesive agent in the junction part vicinity of a motor housing and a metal cover. It is a fragmentary sectional view which shows the modification of embodiment of this invention and shows the axial direction cross section after sealing with the adhesive agent in the joint part vicinity of a motor housing and a metal cover.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and application examples are included in the technical concept of the present invention. Is also included in the range.

  Before describing an embodiment of the present invention, a configuration of an exemplary steering apparatus to which the present invention is applied will be briefly described with reference to FIG.

  First, a steering device for steering the front wheels of an automobile will be described. The steering device 1 is configured as shown in FIG. A pinion (not shown) is provided at the lower end of the steering shaft 2 connected to a steering wheel (not shown), and this pinion meshes with a rack (not shown) that is long in the left-right direction of the vehicle body. Tie rods 3 for steering the front wheels in the left-right direction are connected to both ends of the rack, and the rack is covered with a rack housing 4. A rubber boot 5 is provided between the rack housing 4 and the tie rod 3.

  An electric power steering device 6 is provided to assist torque when the steering wheel is turned. In other words, a torque sensor 7 that detects the turning direction and turning torque of the steering shaft 2 is provided, and an electric motor unit 8 that applies a steering assist force to the rack via the gear 10 based on the detection value of the torque sensor 7. And an electronic control unit (ECU) unit 9 that controls the electric motor disposed in the electric motor unit 8 is provided. The electric motor steering unit 6 of the electric power steering device 6 is connected to the gear 10 through a screw (not shown) at the outer periphery of the output shaft side, and the electronic control unit 9 on the opposite side of the output shaft of the electric motor 8 unit. Is provided.

  In the electric power steering device 6, when the steering shaft 2 is rotated in either direction by operating the steering wheel, the torque sensor 7 determines the rotational direction and the rotational torque of the steering shaft 2. Based on the detected value, the control circuit unit calculates the drive operation amount of the electric motor. The electric motor is driven by the power switching element of the power conversion circuit unit based on the calculated drive operation amount, and the output shaft of the electric motor is rotated so as to drive the steering shaft 1 in the same direction as the operation direction. The rotation of the output shaft is transmitted from a pinion (not shown) to a rack (not shown) via the gear 10 to steer the automobile. Since these structures and operations are already well known, further explanation is omitted.

  As described above, in the electric power steering apparatus having the configuration as disclosed in Patent Document 1, the metal motor housing, the metal heat sink, and the synthetic resin connector case are provided with a fixing portion that protrudes toward the outer peripheral side. It is the structure fastened together by the fixing screw inserted. For this reason, when a fixing part and a fixing screw are provided on the outer periphery of the motor housing, the heat sink, and the connector case, there arises a problem that the external shape becomes large and the weight increases. Furthermore, since the electronic control unit is hermetically sealed with a connector case made of synthetic resin, there is a problem that the connector case does not contribute to heat dissipation and the heat dissipation characteristics are not good.

  Against this background, the present embodiment proposes an electric power steering apparatus having the following configuration. That is, in the present embodiment, there are a predetermined number of fixed recesses recessed inward in the radial direction formed on the outer peripheral surface of the end surface portion of the aluminum-based metal motor housing opposite to the output portion of the rotating shaft of the electric motor. "Screw convex part" that is a fixed convex part that is formed at the opening end of the metal cover that covers the electronic control unit that controls the electric motor and that protrudes inward in the radial direction and is accommodated in the screw concave part. The screw fixing recess is housed in the screw fixing recess, and the head of the fixing screw does not protrude from the outer surface of the metal cover by the “fixing screw” that is a metal fixing means inward from the radial direction. The screwing convex part is fixed to the screwing concave part.

  According to this, the screwing concave part formed on the opening end of the metal cover is accommodated in the screwing concave part formed on the outer peripheral surface of the motor housing, and the metal fixing screw is used inward from the radial direction. Since the screwing convex portion of the metal cover is fixed to the screwing concave portion of the motor housing in a state where the head of the fixing screw does not protrude from the outer surface of the metal cover, the external shape can be reduced and the weight can be reduced. Moreover, since it fixes with a metal fixing screw, the heat from a motor housing is transmitted to a metal cover via a fixing screw, Therefore A heat dissipation characteristic can be improved.

  Hereinafter, a specific configuration of an electric power steering apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. 2 to 13. 2 is a diagram showing the overall configuration of the electric power steering apparatus according to the present embodiment, and FIG. 3 is a diagram showing the components of the electric power steering apparatus shown in FIG. 4 to 9 are views showing a state in which each component is assembled according to the assembly order of each component, and FIG. 10 shows the electric power steering device before sealing with an adhesive. FIG. 11 is a cross-sectional view of the electric power steering apparatus, and shows a cross-section after sealing with an adhesive. FIG. 12 is an adhesive near the joint between the motor housing and the metal cover. FIG. 13 is a drawing showing an axial cross-section before sealing, and FIG. 13 is a drawing showing an axial cross-section after sealing with an adhesive near the joint between the motor housing and the metal cover.Therefore, in the following description, description will be made with reference to each drawing as appropriate.

  As shown in FIG. 2, the electric motor unit 8 constituting the electric power steering apparatus includes a motor housing 11 having a cylindrical part made of aluminum or an aluminum metal such as an aluminum alloy and an electric motor (not shown) housed in the motor housing 11. The electronic control unit 9 is made of an aluminum-based metal such as aluminum or aluminum alloy, or an iron-based metal disposed on the opposite side of the output shaft in the axial direction of the motor housing 11. The metal cover 12 and an electronic control assembly (not shown) housed in the metal cover 12 are included.

  The motor housing 11 and the metal cover 12 are integrally fixed to each other by a fixing screw 37 described later in a predetermined number of fixing regions EA in the outer peripheral direction formed on the opposing end surfaces. The electronic control assembly housed in the metal cover 12 has a power conversion unit having a power switching element made up of a power source circuit unit for generating a necessary power source, a MOSFET or IGBT for driving and controlling the electric motor of the electric motor unit 8. The circuit includes a control circuit unit that controls the power switching element, and the output terminal of the power switching element and the coil input terminal of the electric motor are electrically connected via a bus bar.

  On the end surface of the metal cover 12 opposite to the motor housing 11, the connector terminal assembly 13 is exposed from the hole formed in the metal cover 12. The connector terminal assembly 13 is fixed to a fixing portion formed on the motor housing 11 with a fixing screw. The connector terminal assembly 13 includes a connector terminal forming portion 13A for supplying power, a connector terminal forming portion 13B for detection sensor, and a connector terminal forming portion 13C for sending a control state to send the control state to an external device.

  The electronic control assembly housed in the metal cover 12 is supplied with electric power from the power supply via a connector terminal forming portion 13A for supplying electric power made of synthetic resin, and detects an operating state from detection sensors. The signal is supplied via the connector forming terminal portion 13B for the detection sensor, and the current control state signal of the electric power steering apparatus is sent via the connector terminal forming portion 13C for sending the control state.

  FIG. 3 shows an exploded perspective view of the electric power steering device 6. An annular iron side yoke (not shown) is fitted inside the motor housing 11, and an electric motor (not shown) is accommodated in the side yoke. The output portion 14 of the electric motor applies a steering assist force to the rack via a gear. Since the specific structure of the electric motor is well known, the description thereof is omitted here.

  The motor housing 11 is made of an aluminum alloy, and functions as a heat sink member that releases heat generated by the electric motor and heat generated by a power supply circuit unit and a power conversion circuit unit described later to the outside atmosphere. The electric motor and the motor housing 11 constitute an electric motor unit 8.

  An electronic control unit EC is attached to the end surface portion 15 of the motor housing 11 opposite to the output portion 14 of the electric motor portion 8. The electronic control unit EC includes a power conversion circuit unit 16, a power supply circuit unit 17, a control circuit unit 18, and a connector terminal assembly 13. The end surface portion 15 of the motor housing 11 is formed integrally with the motor housing 11. However, only the end surface portion 15 may be formed separately and integrated with the motor housing 11 by screws or welding. It is.

  Here, the power conversion circuit unit 16, the power conversion circuit unit 17, and the control circuit unit 18 constitute a redundant system, and constitute a dual system of a main electronic control unit and a sub electronic control unit. Normally, the electric motor is controlled and driven by the main electronic control unit, but if an abnormality or failure occurs in the main electronic control unit, the electric motor is controlled and driven by switching to the sub electronic control unit. It will be.

  Therefore, as will be described later, normally, heat from the main electronic control unit is transmitted to the motor housing 11, and if an abnormality or failure occurs in the main electronic control unit, the main electronic control unit stops and the sub electronic control unit operates. The heat from the sub-electronic control unit is transmitted to the motor housing 11.

  However, although not adopted in this embodiment, the main electronic control unit and the sub electronic control unit are combined to function as a regular electronic control unit, and if one electronic control unit malfunctions or fails, the other electronic control unit It is also possible to control and drive the electric motor with half the capacity. In this case, the capacity of the electric motor is halved, but a so-called “limp home function” is ensured. Therefore, in the normal case, heat from the main electronic control unit and the sub electronic control unit is transmitted to the motor housing 11.

  The electronic control unit EC includes a control circuit unit 18, a power supply circuit unit 17, a power conversion circuit unit 16, and a connector terminal assembly 13, and the power conversion circuit unit 16 and the power supply are arranged in a direction away from the end face unit 15 side. The circuit portion 17, the control circuit portion 18, and the connector terminal assembly 13 are arranged in this order. The control circuit unit 18 generates a control signal for driving the switching element of the power conversion circuit unit 16, and includes a microcomputer, peripheral circuits, and the like. The power supply circuit unit 17 generates a power source for driving the control circuit unit 18 and a power source for the power conversion circuit unit 16, and includes a capacitor, a coil, a switching element, and the like. The power conversion circuit unit 16 adjusts the electric power flowing through the coil of the electric motor, and is composed of a switching element or the like constituting a three-phase upper and lower arm.

  The electronic control unit EC generates a large amount of heat mainly from the power conversion circuit unit 16 and the power supply circuit unit 17, and heat from the power conversion circuit unit 16 and the power supply circuit unit 17 is radiated from the motor housing 11 made of an aluminum alloy. It is what is done. This configuration will be described later.

  A connector terminal assembly 13 made of a synthetic resin is provided between the control circuit unit 18 and the metal cover 12, and the current control state of the vehicle battery (power source) and the electric power steering device is externally not shown. Connected to the control device. Needless to say, the connector terminal assembly 13 is connected to the power conversion circuit unit 16, the power supply circuit unit 17, and the control circuit unit 18.

  The metal cover 12 has a function of housing the power conversion circuit unit 16, the power supply circuit unit 17, and the control circuit unit 18 and sealing them in a liquid-tight manner. It is fixed to the motor housing 11 with a metal fixing screw screwed in. The metal fixing screw has a shape such that the head does not protrude outward from the outer surface of the metal cover 12, and details thereof will be described later.

  Therefore, the external shape can be reduced and the weight can be reduced. Further, since the metal cover 12 and the motor housing 11 are fixed by a metal fixing screw, the heat transfer performance between the metal cover 11 and the motor housing can be improved. Furthermore, since the metal cover 12 is made of metal, heat generated by the power conversion circuit unit 16, the power supply circuit unit 17, and the like can be radiated to the outside.

  Next, the configuration of each component and the assembly method will be described with reference to FIGS. First, FIG. 4 shows the appearance of the motor housing 11, and FIG. 5 shows an axial cross section thereof. 4 and 5, the motor housing 11 is formed in a cylindrical shape and closes the side peripheral surface portion 11A, the end surface portion 15 that closes one end of the side peripheral surface portion 11A, and the other end of the side peripheral surface portion 11A. And an end face portion 19. In the present embodiment, the motor housing 11 has a bottomed cylindrical shape, and the side peripheral surface portion 11A and the end surface portion 15 are integrally formed. The end surface portion 19 has a lid function and closes the other end of the side peripheral surface portion 11A after the electric motor is stored in the side peripheral surface portion 11A.

  Further, an annular step portion 35 that is recessed radially inward is formed on the end surface peripheral surface of the end surface portion 15, and the opening end of the metal cover 12 is fitted to the step portion 35. The fitting form of the stepped portion 35 and the open end of the metal cover 12 is a so-called “stamp engagement” or “seal fitting”.

  As shown in FIG. 5, a stator 21 in which a coil 20 is wound around an iron core is fitted inside the side peripheral surface portion 11 </ b> A of the motor housing 11, and a permanent magnet is embedded in the stator 21. The rotor 22 is housed rotatably. A rotation shaft 23 is fixed to the rotor 22, one end is an output unit 14, and the other end is a rotation detection unit 24 for detecting the rotation phase and the number of rotations of the rotation shaft 23. The rotation detection unit 24 is provided with a permanent magnet, and protrudes to the outside through a through hole 25 provided in the end surface portion 15. Then, the rotational phase and the rotational speed of the rotary shaft 23 are detected by a magnetic sensing unit comprising a GMR element or the like (not shown).

  Returning to FIG. 4, the heat conversion portion of the power conversion circuit portion 16 (see FIG. 3) and the power supply circuit portion 17 (see FIG. 3) are disposed on the surface of the end surface portion 15 located on the opposite side of the output portion 14 of the rotating shaft 23. 15A and 15B are formed. The board / connector fixing convex portions 26 are integrally planted at the four corners of the end surface portion 15, and screw holes are formed therein. The board / connector fixing projection 26 is provided to fix the board of the control circuit section 18 and the connector terminal assembly 13 which will be described later. Further, a substrate receiving portion 27 having the same height in the axial direction as a power supply heat radiation region 15B, which will be described later, is formed on the substrate fixing convex portion 26 planted from the power conversion heat radiation region 15A described later. The substrate receiving portion 27 is for mounting and fixing a glass epoxy substrate 31 of the power supply circuit portion 17 to be described later.

  A radial plane region perpendicular to the rotation shaft 23 that forms the end face portion 15 is divided into two. One forms a power conversion heat dissipation region 15A to which a power conversion circuit unit 16 made of a switching element such as a MOSFET is attached, and the other forms a power supply heat dissipation region 15B to which a power supply circuit unit 17 is attached. In the present embodiment, the power conversion heat dissipation region 15A is formed to have a larger area than the power supply heat dissipation region 15B. This is because the installation area of the power conversion circuit unit 16 is secured because the dual system is adopted as described above.

  The power conversion heat dissipation region 15A and the power supply heat dissipation region 15B have steps with different heights in the axial direction (the direction in which the rotating shaft 23 extends). That is, the heat-dissipating region for power supply 15B is formed with a step in a direction away from the heat-dissipating region for power conversion 15A when viewed in the direction of the rotating shaft 23 of the electric motor. This step is set to a length that does not cause interference between the power conversion circuit unit 16 and the power supply circuit unit 17 when the power supply circuit unit 17 is installed after the power conversion circuit unit 16 is installed.

  In the power conversion heat radiation area 15A, three elongated rectangular heat radiation portions 28 are formed. The projecting heat radiating portion 28 is provided with a double power conversion circuit portion 16 to be described later. Further, the protruding heat radiating portion 28 extends so as to protrude in a direction away from the electric motor when viewed in the direction of the rotating shaft 23 of the electric motor.

  Further, the heat radiation area 15B for power supply has a planar shape and is provided with a power supply circuit portion 17 to be described later. Therefore, the projecting heat radiating portion 28 functions as a heat radiating portion that transfers the heat generated in the power conversion circuit portion 16 to the end face portion 15, and the power radiating area 15 B transfers the heat generated in the power circuit portion 17 to the end face portion 15. It functions as a heat radiating part that conducts heat.

  Note that the projecting heat radiating portion 28 can be omitted, and in this case, the power conversion heat radiating region 15 </ b> A functions as a heat radiating portion that transfers heat generated in the power conversion circuit portion 16 to the end face portion 15. However, in the present embodiment, the metal substrate of the power conversion circuit unit 16 is welded to the projecting heat radiating unit 28 by friction stir welding to ensure secure fixing.

  Thus, in the end surface portion 15 of the motor housing 11 according to the present embodiment, the heat sink member is omitted, and the axial length can be shortened. Further, since the motor housing 11 has a sufficient heat capacity, the heat of the power supply circuit unit 17 and the power conversion circuit unit 16 can be efficiently radiated to the outside.

  Next, FIG. 6 shows a state in which the power conversion circuit unit 16 is installed on the protrusion heat radiating unit 28 (see FIG. 4). As shown in FIG. 6, the power conversion circuit unit 16 composed of a double system is installed on the upper part of the protruding heat radiation unit 28 (see FIG. 4) formed in the power conversion heat radiation region 15 </ b> A. The switching elements constituting the power conversion circuit unit 16 are placed on a metal substrate (here, aluminum-based metal is used) and are configured to be easily radiated. The metal substrate is welded to the projecting heat radiation portion 28 by friction stir welding.

  Therefore, the metal substrate is firmly fixed to the projecting heat radiating portion 28 (see FIG. 4), and heat generated by the switching element can be efficiently transferred to the projecting heat radiating portion 28 (see FIG. 4). The heat transmitted to the projecting heat radiating portion 28 (see FIG. 4) is diffused to the power conversion heat radiating region 15A, further transferred to the side peripheral surface portion 11A of the motor housing 11, and radiated to the outside. Here, as described above, since the height of the power conversion circuit unit 16 in the axial direction is lower than the height of the heat dissipation region 15B for power supply, it does not interfere with the power supply circuit unit 17 described later.

  In this way, the power conversion circuit unit 16 is installed on the upper portion of the protruding heat dissipation unit 28 formed in the heat conversion heat dissipation region 15A. Therefore, the heat generated by the switching element of the power conversion circuit unit 16 can be efficiently transferred to the projecting heat radiating unit 28. Further, the heat transferred to the projecting heat radiating portion 28 is diffused to the power conversion heat radiating region 15A, and is transferred to the side peripheral surface portion 11A of the motor housing 11 to be radiated to the outside.

  Next, FIG. 7 shows a state in which the power supply circuit unit 17 is installed from above the power conversion circuit unit 16. As shown in FIG. 7, a power supply circuit unit 17 is installed above the heat dissipation region 15B for power supply. A capacitor 29, a coil 30 and the like constituting the power supply circuit unit 17 are placed on a glass epoxy substrate 31. The power supply circuit unit 17 also adopts a double system, and as can be seen from the figure, a power supply circuit composed of a capacitor 29, a coil 30, and the like is formed symmetrically. An electrical element such as a capacitor other than the switching element of the power conversion circuit 16 is placed on the glass epoxy substrate 31.

  The surface of the glass epoxy substrate 31 on the side of the power radiation area 15B (see FIG. 6) is fixed to the end face portion 15 so as to be in contact with the power radiation area 15B. As shown in FIG. 7, the fixing method is to fix the screw hole provided in the substrate receiving portion 27 of the substrate fixing convex portion 26 with a fixing screw (not shown). Further, it is also fixed to a screw hole provided in the power radiation region 15B (see FIG. 6) by a fixing screw (not shown).

  In addition, since the power supply circuit part 17 is formed with the glass epoxy board | substrate 31, double-sided mounting is possible. The surface of the glass epoxy substrate 31 on the side of the heat radiation area 15B for power supply (see FIG. 6) is mounted with a rotational phase / rotational speed detection unit including a GMR element (not shown) and its detection circuit. In cooperation with the rotation detection unit 24 (see FIG. 5) provided in FIG. 5, the rotation phase and the number of rotations are detected.

  As described above, the glass epoxy substrate 31 is fixed so as to be in contact with the power supply heat dissipation region 15B (see FIG. 6). Therefore, the heat generated in the power supply circuit unit 17 is efficiently transferred to the power supply heat dissipation region 15B (FIG. 6). Heat transfer). The heat transferred to the heat dissipation region 15B for power supply (see FIG. 6) is diffused and transferred to the side peripheral surface portion 11A of the motor housing 11 to be radiated to the outside. Here, between the glass epoxy substrate 31 and the heat radiation area 15B for power supply (see FIG. 6), any one of an adhesive, a heat radiation grease, and a heat radiation sheet having a good heat transfer property is interposed to further increase the heat transfer performance. Can be improved.

  As described above, the power supply circuit unit 17 is installed on the upper portion of the heat dissipation region 15B for power supply. The surface of the glass epoxy substrate 31 on which the circuit elements of the power supply circuit section 17 are placed is fixed to the end face section 15 so as to be in contact with the power supply heat dissipation area 15B. Therefore, the heat generated in the power supply circuit unit 17 can be efficiently transferred to the heat dissipation region 15B for power supply. The heat transmitted to the power radiation region 15B is diffused and transferred to the side peripheral surface portion 11A of the motor housing 11 to be radiated to the outside.

  Next, FIG. 8 shows a state in which the control circuit unit 18 is installed from above the power supply circuit unit 17. As shown in FIG. 8, the control circuit unit 18 is installed above the power supply circuit unit 17. The microcomputer 32 and the peripheral circuit 33 constituting the control circuit unit 18 are placed on a glass epoxy substrate 34. The control circuit unit 18 also adopts a double system, and as can be seen from the figure, a control circuit including a microcomputer 32 and a peripheral circuit 33 is formed for each target. The microcomputer 32 and the peripheral circuit 33 may be provided on the surface of the glass epoxy substrate 34 on the power supply circuit 17 side.

  As shown in FIG. 8, the glass epoxy board 34 is fixed by a fixing screw (not shown) in a form of being sandwiched by the connector terminal assembly 13 in a screw hole provided at the top of the board fixing convex portion 26 (see FIG. 7). 7 is disposed between the glass epoxy substrate 31 of the power supply circuit unit 17 (see FIG. 7) and the glass epoxy substrate 34 of the control circuit unit 18. It is a space.

  Next, FIG. 9 shows a state in which the connector terminal assembly 13 is installed from above the control circuit unit 18. As shown in FIG. 9, the connector terminal assembly 13 is installed above the control source circuit section 18. The connector terminal assembly 13 is fixed by a fixing screw 36 so as to sandwich the control circuit portion 18 in a screw hole provided at the top of the board fixing convex portion 26. In this state, as shown in FIG. 3, the connector terminal assembly 13 is connected to the power conversion circuit unit 16, the power supply circuit unit 17, and the control circuit unit 18, and the open end of the metal cover 12 is connected to the step of the motor housing 11. It is fitted to the portion 35 by means of a seal fitting or the like, and fixed with a fixing screw 37 in a predetermined number of fixing areas EA provided in the outer peripheral direction.

  Here, the fixing area EA will be described with reference to FIG. 10, but FIG. 10 shows a state before sealing with an adhesive. In the vicinity of the step portion 35 of the side peripheral surface portion 11A of the motor housing 11, in other words, in the vicinity of the fitting surface with the metal cover 12, a predetermined number (here, three at equal intervals) of screwing recesses 38 are formed. . The screwing recess 38 is recessed inward in the radial direction and has a function of accommodating a screwing protrusion of the metal cover 12 described later.

  The metal cover 12 is formed with a screwing convex portion 39 that is accommodated in the screwing concave portion 38, and the screw is opened in a state where the open end of the metal cover 12 is fitted to the step portion 35 on the end surface of the motor housing 11. The stop convex part 39 is configured to be accommodated in the screw stop concave part 38. The screwing convex portion 39 is a tongue-like shape formed by forming a pair of parallel cutouts at a part of the opening end of the metal cover 12 and bending the opening end between the cutouts so as to protrude inward. It is formed in the shape of.

  Thus, when the screwing convex part 39 is formed by a notch, there exists an effect that it is easy to process. In addition, the screwing convex part 39 can also be formed using a plastic deformation other than the method by a notch. In this case, it can be formed by using an extrusion jig so that the open end of the metal cover 12 protrudes inward.

  In addition, a positioning portion 40 formed in a complementary shape is formed on the side peripheral surface portion 11 </ b> A of the motor housing 11 and the opposing surface of the opening end of the metal cover 12. As a result, the metal cover 12 and the motor housing 11 can be positioned.

  Here, the opposing surface of the side peripheral surface portion 11A of the motor housing 11 and the opening end of the metal cover 12 is sealed with an adhesive, but in a state before sealing, the side peripheral surface portion 11A of the motor housing 11 and the metal are sealed. The opposed surfaces of the opening end of the cover 12 are fixed to each other through a gap of a predetermined distance G. The reason why the gap of the predetermined distance G is formed in this way is to ensure a watertight function so that a sufficient amount of adhesive can be applied. Without forming the gap of the predetermined distance G, the adhesive does not penetrate into the contact surface when the side peripheral surface portion 11A of the motor housing 11 and the facing surface of the opening end of the metal cover 12 are in contact with each other. This is because there is a fear that it cannot be secured.

  FIG. 11 shows an axial section of the electric power steering apparatus shown in FIG. In addition, in this FIG. 11, the cross section of the state which sealed with the adhesive agent is shown. A screw hole 41 into which the fixing screw 37 is screwed is formed in the heat dissipation region 15B for power supply formed in the end surface portion 15 of the motor housing 11. In order to form the screw hole 41, a thickness greater than a predetermined thickness larger than the diameter of the screw hole 41 is required. In the present embodiment, the heat dissipation region 15B for the power supply that is higher in the axial direction than the heat dissipation region 15A for power conversion. Therefore, a sufficient thickness for forming the screw hole 41 is provided.

  A screwing concave portion 38 formed at the opening end of the metal cover 12 is accommodated in the screwing concave portion 38 formed near the outer peripheral surface of the end surface portion 15 of the motor housing 11. In this state, the fixing screw 37 passes through an insertion hole (not shown) drilled in the screwing convex part 39 and is screwed into the screw hole 41 formed in the heat radiation area 15B for the power supply. The part 39 is fixed to the screwing recess 38. The screw hole 41 is formed in the radial direction toward the axial center side of the rotary shaft 23.

  Here, one fixing screw 37 is screwed into the screw hole 41 formed in the thick heat-dissipating region 15B for power supply, but the remaining two fixing screws 37 are planted from the heat-dissipating region 15A for power conversion. It is screwed into a screw hole (not shown) formed in the substrate fixing convex portion 26 (see FIG. 4). This screw hole (not shown) is also formed in the radial direction toward the axial center side of the rotating shaft 23.

  An opposing surface between the opening end of the metal cover 12 and the outer peripheral surface of the end surface portion 15 of the motor housing 11 is filled with an adhesive 42 to provide a watertight function. The adhesive 42 is filled so as to cover the screwing concave portion 38 and the screwing convex portion 39 fixed by the fixing screw 37 from the outside, including the fixing screw 37, and to cover the metal. A gap having a predetermined distance G formed between the opening end of the cover 12 and the end surface portion 15 of the motor housing 11 is also filled. This makes it possible to prevent moisture from entering the inside from the vicinity of the joint between the metal cover 12 and the end surface portion 15 of the motor housing 11.

  In addition, since the fixing screw 37 fixes the metal cover 12 and the end surface portion 15 of the motor housing 11 from the radial direction to the inside, the fixing portion is not exposed to the outside as in Patent Document 1, so that the external shape can be reduced. Also, the weight can be reduced.

  FIG. 12 shows an enlarged cross section before sealing between the metal cover 12 and the end surface portion 15 of the motor housing 11 with the adhesive 42, and FIG. 13 shows an end surface portion of the metal cover 12 and the motor housing 11 with the adhesive 42. The expanded cross section after sealing between 15 is shown.

  In FIG. 12, the opening end between the pair of parallel cutouts formed at the opening end of the metal cover 12 is bent so as to protrude inward in the radial direction, and a screwing convex portion 39 is formed. Yes. Further, the outer peripheral surface of the end surface portion 15 of the motor housing 11, preferably the heat radiation area 15 </ b> B for power supply, and the outer peripheral surface portion of the substrate fixing convex portion 26 (see FIG. 4) are screwed concave portions 38 so as to be recessed inward in the radial direction. Is formed. The screwing convex part 39 of the metal cover 12 is accommodated in the screwing concave part 38 of the end surface part 15 of the motor housing 11. Further, the fixing screw 37 is screwed so as to fix the screwing convex part 39 of the metal cover 12 to the screwing concave part of the end surface part 15 of the motor housing 11 from the radial direction to the inside.

  In this state, the head 37 </ b> H of the fixing screw 37 is dimensioned so as not to protrude outward from the outer surface 12 </ b> OS of the metal cover 12, and in the vicinity of the joint between the metal cover 12 and the end surface portion 15 of the motor housing 11. The appearance is determined by the shape of the metal cover 12. That is, the fixing portion of the fixing screw 37 does not protrude outward from the outer peripheral surface 12OS of the metal cover. Thereby, since the fixing portion is not exposed to the outside as in Patent Document 1, the appearance shape can be reduced.

  Next, as shown in FIG. 13, an adhesive 42 is filled in an opposing surface between the opening end of the metal cover 12 and the outer peripheral surface of the end surface portion 15 of the motor housing 11 to obtain a watertight function. The adhesive 42 uses a synthetic resin having adhesiveness, and in this embodiment, a silicon rubber-based elastic adhesive is used. Silicon rubber-based elastic adhesives have the property of absorbing stresses such as external vibrations and impacts, so that the stress is less likely to concentrate on the bonding interface. For this reason, there is a risk that the adhesive interface will be peeled off and the watertight function may be lost if vibration, impact, etc. are applied like an electric power steering device, but the watertight function can be achieved by using a silicone rubber-based elastic adhesive. Can reduce the risk of loss. In the present embodiment, since the sealing is performed with the adhesive 42, the O-ring for watertightness that has been conventionally used can be omitted. Further, the silicon-based elastic adhesive 42 may be a liquid gasket (FIPG: FORED IN PLACE GASKET) having an adhesive function, and is made of a material that is cured at room temperature or heat. can do.

  The adhesive 42 is filled so as to cover from the outside including the screwing concave portion 38, the screwing convex portion 39, and the fixing screw 37, which are fixed by the fixing screw 37. A gap having a predetermined distance G formed between the open end and the end surface portion 15 of the motor housing 11 is also filled. This makes it possible to prevent moisture from entering the inside from the vicinity of the joint between the metal cover 12 and the end surface portion 15 of the motor housing 11.

  Further, since the metal cover 12 and the motor housing 11 are fixed by the metal fixing screw 37, the heat of the motor housing 11 can be transmitted to the metal cover 12 via the fixing screw 37. As a result, heat can be radiated from the metal cover 12 as well, so that the heat dissipation characteristics of the electric power steering device as a whole can be improved.

  Next, a modification of the present invention will be described with reference to FIG. In FIG. 13, the fixing screw 37 is used as the fixing means, but the modified example shown in FIG. 14 uses a rivet as the fixing means.

  In FIG. 14, the opening end between the pair of parallel cutouts formed at the opening end of the metal cover 12 is bent so as to protrude inward in the radial direction, and a riveting protrusion as a fixed protrusion 43 is formed. Further, the outer peripheral surface of the end surface portion 15 of the motor housing 11, preferably the heat radiation area 15 </ b> B for the power supply, and the outer peripheral surface portion of the substrate fixing convex portion 26 (see FIG. 4) A stop recess 44 is formed. The riveting protrusion 43 of the metal cover 12 is housed in the riveting recess 44 of the end surface portion 15 of the motor housing 11. A fixed rivet 45 is driven inward from the radial direction so as to fix the rivet-fixing convex portion 43 of the metal cover 12 to the rivet-fixing concave portion 44 of the end surface portion 15 of the motor housing 11.

  In this state, the head 45H of the fixed rivet 45 is dimensioned so as not to protrude outward from the outer surface 12OS (see FIG. 12) of the metal cover 12, and the end face portion 15 of the metal cover 12 and the motor housing 11 is determined. The appearance of the vicinity of the joint is determined by the shape of the metal cover 12. That is, the fixed portion of the fixed rivet 45 is prevented from coming out from the outer peripheral surface 12OS of the metal cover. Thereby, since the fixing portion is not exposed to the outside as in Patent Document 1, the appearance shape can be reduced.

  Here, in the hollow portion 15G formed in the end surface portion 15 of the motor housing 11, an expanded portion 45E is formed at the tip of the fixed rivet 45, and the fixed rivet 45 that has been driven in is prevented from coming out. In order to form the expanded portion 45E, for example, a push rivet can be used. The opposing surface between the opening end of the metal cover 12 and the outer peripheral surface of the end surface portion 15 of the motor housing 11 is filled with an adhesive 42 to obtain a watertight function. The adhesive 42 is the same as described above.

  The adhesive 42 is filled so as to cover from the outside including the riveting concave portion 44, the riveting convex portion 43, and the fixed rivet 45, which are fixed by a fixed rivet 45. And a gap having a predetermined distance G formed between the end face portion 15 of the motor housing 11 is also filled. This makes it possible to prevent moisture from entering the inside from the vicinity of the joint between the metal cover 12 and the end surface portion 15 of the motor housing 11.

  Further, since the metal cover 12 and the motor housing 11 are fixed by the metal fixed rivet 45, the heat of the motor housing 11 can be transmitted to the metal cover 12 through the fixed rivet 45. As a result, heat can be radiated from the metal cover 12 as well, so that the heat dissipation characteristics of the electric power steering device as a whole can be improved.

  As described above, the present invention includes a predetermined number of screw recesses recessed radially inwardly on the outer peripheral surface of the end surface portion of the aluminum-based metal motor housing opposite to the output portion of the rotating shaft of the electric motor. A screwing convex portion protruding inward in the radial direction and housed in a screwing concave portion formed on the outer peripheral surface of the metal cover that covers the electronic control unit that controls the electric motor. The screwing convex part was fixed to the screwing concave part in a state where the head of the fixing screw did not protrude from the outer surface of the metal cover by the metal fixing screw from the radial direction toward the inside.

  As a result, the screwing concave portion formed on the outer peripheral surface of the metal cover is accommodated in the screwing concave portion formed on the outer peripheral surface of the motor housing, and the fixing screw is fixed by the metal fixing screw inward from the radial direction. Since the screwing convex part of the metal cover is fixed to the screwing concave part of the motor housing in a state where the head of the metal cover does not protrude from the outer surface of the metal cover, the external shape can be reduced and the weight can be reduced. Moreover, since it fixes with a metal fixing screw, the heat of a motor housing can be transmitted to a metal cover via a fixing screw, Therefore A heat dissipation characteristic can be improved.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  DESCRIPTION OF SYMBOLS 6 ... Electric power steering apparatus, 8 ... Electric motor part, 9 ... Electronic control part, 11 ... Motor housing, 12 ... Metal cover, 13 ... Connector terminal assembly, 14 ... Output part, 15 ... End surface part, 15A ... Power conversion Heat dissipation area, 15B ... heat dissipation area for power supply, 16 ... power conversion circuit section, 17 ... power supply circuit section, 18 ... control circuit section, 19 ... end face section, 20 ... coil, 21 ... stator, 22 ... rotor, 23 ... rotation Axis 24: Rotation detection part 25 ... Through hole 26 ... Substrate fixing convex part 27 ... Substrate receiving part 28 ... Projection heat dissipation part 29 ... Capacitor 30 ... Coil 31 ... Glass epoxy board 32 ... Microphone Computer, 33 ... Peripheral circuit, 34 ... Glass epoxy board, 35 ... Step part, 37 ... Fixing screw, 38 ... Screwing concave part, 39 ... Screwing convex part, 40 ... Positioning part, 41 ... Screw hole, 42 ... Contact Agent, EA ... fixed area.

Claims (12)

A motor housing made of an aluminum metal in which an electric motor for driving a mechanical control element is housed, and an end surface portion of the motor housing opposite to an output portion of the rotating shaft of the electric motor; An electronic control unit including a control circuit unit for driving the electric motor, a power supply circuit unit, and a power conversion circuit unit, and a metal metal cover that covers the electronic control unit,
On the outer peripheral surface of the end surface portion of the motor housing opposite to the output portion of the rotating shaft of the electric motor, a predetermined number of fixed concave portions that are recessed radially inward are formed,
At the opening end of the metal cover that covers the electronic control unit, a fixed convex portion that protrudes inward in the radial direction and is accommodated in the fixed concave portion is formed,
In a state where the fixed convex portion is housed in the fixed concave portion, the fixed convex portion prevents the head of the fixing means from protruding from the outer surface of the metal cover by a metal fixing means inward from the radial direction. An electric drive device characterized in that a portion is fixed to the fixed recess. The electric drive device according to claim 1,
On the outer peripheral surface of the end surface portion of the motor housing opposite to the output portion of the rotating shaft of the electric motor, screw fixing recesses as a predetermined number of fixing recesses recessed radially inward are formed,
At the opening end of the metal cover that covers the electronic control unit, a screwing convex part is formed as the fixed convex part that protrudes radially inwardly accommodated in the screwing concave part,
With the screwing convex portion housed in the screwing concave portion, the head of the fixing screw is moved from the outer surface of the metal cover by the fixing screw as the metal fixing means inward from the radial direction. The electric drive device, wherein the screwing convex portion is fixed to the screwing concave portion so as not to protrude. The electric drive device according to claim 1,
On the outer peripheral surface of the end surface portion of the motor housing opposite to the output portion of the rotating shaft of the electric motor, a predetermined number of riveting recesses as the fixed recesses recessed radially inward are formed,
At the opening end of the metal cover that covers the electronic control unit, a rivet-fixing convex portion is formed as the fixed convex portion that protrudes inward in the radial direction stored in the rivet-fixing concave portion,
With the rivet-fixing convex portion housed in the rivet-fixing recess, the fixed rivet head is moved from the outer surface of the metal cover by the fixing rivet as the metal fixing means from the radial direction to the inside. The electric drive device characterized in that the riveting convex portion is fixed to the riveting concave portion so as not to protrude. The electric drive device according to claim 2,
A power conversion heat dissipation area and a power supply heat dissipation area are formed in the end surface portion of the motor housing, the power conversion circuit section is installed in the power conversion heat dissipation area, and the power supply heat dissipation area includes the power supply. The circuit is installed,
The power heat radiation area formed on the end surface portion of the motor housing is formed with a step in a direction away from the power conversion heat radiation area when viewed in the direction in which the rotating shaft of the electric motor extends. One of the screwing recesses is formed in the heat dissipation region for the power source. The electric drive device according to claim 2,
The fixing screw, the screwing convex part, and the screwing concave part are covered from the outside with an adhesive having a watertight function, and the end face part of the motor housing and the opposing surface of the metal cover are provided with the watertight function. An electric drive device characterized by being filled with an adhesive. The electric drive device according to claim 2,
The screw driving convex portion is formed by bending the opening end between a pair of parallel cutouts formed at the opening end of the metal cover inward. An electric motor that applies a steering assist force to the steering shaft based on an output from a torque sensor that detects a turning direction and a turning torque of the steering shaft, a motor housing that houses the electric motor, and rotation of the electric motor An electronic control unit including a control circuit unit for driving the electric motor, a power supply circuit unit, and a power conversion circuit unit, which is disposed on the side of the end surface of the motor housing opposite to the output unit of the shaft; A metal metal cover covering the electronic control unit,
On the outer peripheral surface of the end surface portion of the motor housing opposite to the output portion of the rotating shaft of the electric motor, a predetermined number of fixed concave portions that are recessed radially inward are formed,
At the opening end of the metal cover that covers the electronic control unit, a fixed convex portion that protrudes inward in the radial direction and is accommodated in the fixed concave portion is formed,
In a state where the fixed convex portion is housed in the fixed concave portion, the fixed convex portion prevents the head of the fixing means from protruding from the outer surface of the metal cover by a metal fixing means inward from the radial direction. An electric power steering apparatus characterized in that a portion is fixed to the fixed recess. The electric power steering apparatus according to claim 7,
On the outer peripheral surface of the end surface portion of the motor housing opposite to the output portion of the rotating shaft of the electric motor, screw fixing recesses as a predetermined number of fixing recesses recessed radially inward are formed,
At the opening end of the metal cover that covers the electronic control unit, a screwing convex part is formed as the fixed convex part that protrudes radially inwardly accommodated in the screwing concave part,
With the screwing convex portion housed in the screwing concave portion, the head of the fixing screw is moved from the outer surface of the metal cover by the fixing screw as the metal fixing means inward from the radial direction. The electric power steering apparatus, wherein the screwing convex portion is fixed to the screwing concave portion so as not to protrude. The electric power steering apparatus according to claim 7,
On the outer peripheral surface of the end surface portion of the motor housing opposite to the output portion of the rotating shaft of the electric motor, a predetermined number of riveting recesses as the fixed recesses recessed radially inward are formed,
At the opening end of the metal cover that covers the electronic control unit, a rivet-fixing convex portion is formed as the fixed convex portion that protrudes inward in the radial direction stored in the rivet-fixing concave portion,
With the rivet-fixing convex portion housed in the rivet-fixing recess, the fixed rivet head is moved from the outer surface of the metal cover by the fixing rivet as the metal fixing means from the radial direction to the inside. The electric power steering apparatus, wherein the rivet-fixing convex part is fixed to the rivet-fixing concave part so as not to protrude. The electric power steering apparatus according to claim 8,
A power conversion heat dissipation area and a power supply heat dissipation area are formed in the end surface portion of the motor housing, the power conversion circuit section is installed in the power conversion heat dissipation area, and the power supply heat dissipation area includes the power supply. The circuit is installed,
The power heat radiation area formed on the end surface portion of the motor housing is formed with a step in a direction away from the power conversion heat radiation area when viewed in the direction in which the rotating shaft of the electric motor extends. One of the screwing recesses is formed in the heat dissipation region for the power source. The electric power steering apparatus according to claim 8,
The fixing screw, the screwing convex part, and the screwing concave part are covered with an adhesive having a watertight function, and the end surface part of the motor housing and the opposing surface of the metal cover have the watertight function. An electric power steering apparatus characterized by being filled with an adhesive. The electric power steering apparatus according to claim 8,
The electric power steering device according to claim 1, wherein the screwing convex portion is formed by bending the opening end between a pair of parallel cutouts formed at the opening end of the metal cover inward.

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