JP2015201957A - motor control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control device capable of decreasing the number of components and reducing man-hours for assembly.SOLUTION: A contact part 13 in a V-shaped protruding form toward a switching element 10 is formed in a portion of a bus bar 12 opposite to the switching element 10. When a resin module 14 is fixed, a bottom face of a distal end of the contact part 13 is brought into contact with a top face of an electrode terminal 11 of the switching element 10 disposed between a main body of the switching element 10 and the bus bar 12. The contact part 13 applies a pressing force F in a direction toward a heat sink 9 to the switching element 10. A distance D between the heat sink 9 and the resin module 14 is set smaller than an addition value of thickness t1 of the switching element 10 and thickness t2 of the contact part 13 and the electrode terminal 11. Therefore, the contact part 13 presses the electrode terminal 11 and an interval after contact is reduced. The bus bar 12 presses the switching element 10 and the switching element 9 is brought into tight contact with the heat sink 6.

Description

  The present invention relates to a motor control device, and more particularly to a motor control device having an inverter circuit cooling structure configured by connecting a plurality of switching elements to a bus bar.

  Conventionally, as an in-vehicle motor control device used for an electric power steering device or the like, a control including an inverter circuit that converts a DC voltage supplied from a power source such as a battery into a three-phase AC voltage, and a microcomputer that drives the inverter circuit An apparatus including a circuit is known (for example, see Patent Document 1). The motor control device described in Patent Document 1 includes a heat sink for improving the heat dissipation of a power MOSFET (hereinafter referred to as FET) of a switching element provided in an inverter circuit. The plurality of FETs are fixed in close contact with the surface of the heat sink by being fastened to the heat sink with screws.

JP 2011-238850 A

However, in such a motor control device, fixing parts such as screws and a dedicated presser plate are required to fix the FET to the heat sink. Further, in order to electrically connect the bus bar to the FET, the bus bar is joined to the FET by soldering or welding via a substrate or directly. For this reason, fixing to the heat sink is one of the factors that increase the number of parts, and the control device is enlarged. Has led to an increase.
Such a problem is not limited to the motor control device, and is common to various electronic devices including a heat sink for improving heat dissipation of heat-generating components such as FETs.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a motor control device that can reduce the number of parts and the number of assembly steps.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a motor control device, wherein a switching element of an inverter that supplies a drive voltage to a motor body, and heat generated by the switching element is released in contact with the switching element. A heat sink, a bus bar for supplying a voltage from an external power source to the switching element, and a resin module that integrally accommodates the bus bar and is fixed to a housing, the bus bar having an electrode terminal of the switching element A projecting contact portion that is electrically connected to the contact portion is formed, and the switching element and the heat sink are brought into close contact with each other by a pressing force applied from the contact portion.

  According to the above configuration, the bus bar has the protruding contact portion that contacts the electrode terminal of the switching element, and the contact portion presses the electrode terminal electrically when fixing the resin module in which the bus bar is accommodated. Connected. At this time, the switching element is pressed against and adhered to the heat sink by the pressing force applied from the contact portion. This eliminates the need for fixing parts such as screws and pressing plates for bringing the switching element and the heat sink into close contact with each other, thereby reducing the number of parts. Further, since the bus bar and the switching element can be electrically connected and conducted stably, a joining process such as soldering or welding becomes unnecessary, and the number of assembling steps can be reduced.

  According to a second aspect of the present invention, in the motor control device according to the first aspect, the switching element is disposed between the bus bar and the heat sink, and the contact portion faces the switching element in the bus bar. The gist of the present invention is that the electrode terminal is formed between the resin module and the switching element and bends and extends between the resin module and the switching element and is pressed in the opposite direction.

  According to the above configuration, when the switching element is installed between the bus bar and the heat sink, the contact portion is formed in a portion of the bus bar facing the switching element. The electrode terminal comes into contact with the bus bar and is pressed in the opposite direction by the pressing force applied from the contact portion. For this reason, the switching element is electrically connected to the bus bar by pressing the bus bar when the resin module is assembled and fixed, and is closely attached to the heat sink by pressing the switching element against the heat sink. This eliminates the need for fixed parts such as screws and pressing plates, thereby reducing the number of parts. In addition, since the joining process between the bus bar and the electrode terminal is not required, the number of assembling steps can be reduced.

  According to a third aspect of the present invention, in the motor control device according to the second aspect of the present invention, the distance between the opposing surfaces of the resin module and the heat sink is the thickness of the switching element, the contact portion before pressing, and The gist is that the thickness is set smaller than the sum of the thicknesses of the electrode terminals.

  According to the above configuration, the distance between the opposing resin module and the surface of the heat sink is based on the sum of the thickness of the switching element body and the thickness of the contact portion before pressing and the thickness of each electrode terminal of the switching element. Is also set to a small value. For this reason, when the resin module is assembled and fixed, the contact portion presses the electrode terminal of the switching element, and the contact portion or the electrode terminal is deformed to reduce the thickness. As a result, the bus bar presses the switching element, and the switching element can be securely adhered to the heat sink.

  ADVANTAGE OF THE INVENTION According to this invention, while reducing a number of parts, the motor control apparatus which can reduce an assembly man-hour can be provided.

1 is a partial cross-sectional view showing a schematic structure of a motor device including a motor control device according to an embodiment of the present invention. The circuit diagram for demonstrating operation | movement of the motor control apparatus of FIG. The figure which shows the detailed structure of the bus-bar and switching element of the motor control apparatus of FIG. 1 which concerns on the 1st Embodiment of this invention. (A) is a figure which shows the shape of the contact part of the bus-bar which concerns on 2nd Embodiment of this invention, (b) is a figure which shows the shape of the contact part of the bus-bar which concerns on the 3rd Embodiment of this invention. The figure which shows the detailed structure of the bus-bar and switching element of the motor control apparatus which concerns on other embodiment of this invention.

  Hereinafter, the motor control device 3 according to the embodiment of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a partial cross-sectional view showing a schematic structure of a motor device 1 including a motor control device 3 according to an embodiment of the present invention. A motor device (motor control unit) 1 according to the present embodiment includes a motor main body 2 and a motor control device 3, and is mounted on an electric power steering device, for example, as a power source for applying assist force to a steering mechanism. It is used.

  As shown in FIG. 1, the motor device 1 has a structure in which a motor body 2 and a motor control device 3 that controls a drive voltage supplied to the motor body 2 through an electronic component including a plurality of switching elements 10 are integrated. Become. The motor main body 2 and the motor control device 3 are respectively housed in a motor housing 4 and an ECU housing 5 that are formed in a cylindrical shape around the rotation axis m. The motor housing 4 and the ECU housing 5 are integrally connected by screws or the like.

  The motor control device 3 includes a heat sink 9, a switching element 10, and a resin module 14 that are arranged in order from the side closer to the motor body 2 upward. The heat sink 9 and the resin module 14 are fixed to the motor housing 4 and the ECU housing 5 through a support structure (not shown), respectively.

  The resin module 14 has a structure in which a bus bar 12 made of a flat conductor (for example, copper or a copper alloy) is integrally accommodated and an electronic component such as a filter for removing noise including a smoothing capacitor described later is resin-sealed. . The resin module 14 is formed so as to extend in a horizontal direction (left-right direction in the figure) orthogonal to the rotation axis m. The resin module 14 has an external power source 6 such as a battery, which will be described later, via a wiring portion (for example, an electric wire or a bus bar member) 7 led out of the ECU housing 5 from a surface opposite to the surface facing the heat sink 9. It is connected to the.

  For example, the bus bar 12 protrudes from the surface of the resin module 14 facing the heat sink 9 and extends rightward in the drawing with respect to the switching element (for example, FET) 10, and a contact portion 13 is formed at the tip. Yes. The contact portion 13 is in contact with an electrode terminal (for example, three terminals of a gate, a source, and a drain) 11 that is a connection wiring portion of the switching element 10 and presses the switching element 10.

  The resin module 14 removes noise included in the DC voltage supplied from the external power source 6 via the wiring unit 7 through a filter or the like, and the DC voltage from which noise has been removed is applied to the switching element 10 or the like via the bus bar 12. Supply.

  The heat sink 9 is disposed so as to extend in the horizontal direction perpendicular to the rotation axis m. On the heat sink 9, various electronic components such as a switching element (FET) 10 of a power system circuit mainly composed of an inverter circuit are mounted. Among the mounted electronic components, the switching element 10 constituting the inverter circuit is disposed between the heat sink 9 and the bus bar 12.

  The electrode terminal 11 of the switching element 10 is bent and extends between the bus bar 12 and the main body of the switching element 10 in the horizontal direction (left direction in the figure), and the tip part contacts the contact part 13 of the bus bar 12. It is pressed. As a result, the heat radiating surface that emits heat from the switching element 10 is fixed in close contact with the surface of the heat sink 9 at a position facing the heat sink 9.

  The switching element 10 generates an AC voltage to be supplied to the motor body 2 from the DC voltage of the external power supply 6 supplied from the resin module 14 via the bus bar 12. The generated AC voltage is supplied to the motor body 2 via a power supply system bus bar (not shown). The motor body 2 is driven based on the supplied AC voltage, and rotates the motor output shaft 8 coupled to the motor body 2.

Next, FIG. 2 is a circuit diagram for explaining the operation of the motor control device 3 of FIG.
As shown in FIG. 2, the motor control device 3 includes a large-capacity smoothing capacitor 16 and an inverter 17 that is connected in parallel to the smoothing capacitor 16 and supplies a drive voltage to the motor body 2. The motor main body 2 is connected to the motor control device 3 via a battery 15 as an external power source and an inverter 17. In FIG. 2, the motor body 2 is a three-phase brushless motor having three-phase windings (U-phase, V-phase, and W-phase windings) not shown. The battery 15 is a low voltage (for example, 12 V) or high voltage (for example, 100 V or more) DC power source that is connected to the inverter 17 and drives the motor body 2.

  The smoothing capacitor 16 is provided between the positive and negative power supply lines 18 and the ground line 19 of the battery 15. The smoothing capacitor 16 supplies power to the inverter 17 from both the battery 15 and the inverter 17. In particular, the smoothing capacitor 16 instantaneously supplies large power to the inverter 17. Specifically, the smoothing capacitor 16 accumulates charges, and discharges the accumulated charges when the current flowing from the battery 15 to the inverter 17 is insufficient. In this way, the smoothing capacitor 16 functions as a capacitor that absorbs current ripple and smoothes the power supply voltage for driving the motor body 2.

  The inverter 17 includes a plurality (six in this embodiment) of switching elements (eg, FET, IGBT, etc.) 10a, 10b, 10c, 10d, 10e, 10f. Three circuits in which two of these six switching elements 10a to 10f are connected in series to form upper and lower arms (for example, 10a and 10d) are provided in parallel between the power line 18 and the ground line 19. It has been. Each connection point of the switching elements 10 of the upper and lower arms is directly connected to one end of the U-phase, V-phase, and W-phase windings of the motor body 2. The other end of the three-phase winding of the motor body 2 is connected to a common connection point (neutral point) not shown.

  Each switching element 10a to 10f included in the inverter 17 is controlled by a control circuit (not shown). More specifically, the control circuit determines a target value (three-phase drive current (U-phase, V-phase, and W-phase current)) to be supplied to the motor body 2 based on input data such as a motor rotation angle. Target current) is determined, and a PWM signal for matching each phase current value detected by a current sensor (not shown) with the target current is output. The PWM signal of each phase output from the control circuit is supplied to the gate terminals of the switching elements 10a to 10f included in the inverter 17, respectively.

<First Embodiment>
Next, the structure around the switching element 10 according to the first embodiment of the present invention will be described.
FIG. 3 is a diagram showing a detailed structure of the bus bar 12 and the switching element 10 of the motor control device 3 of FIG. 1 according to the first embodiment of the present invention.

  As shown in FIG. 3, a contact portion 13 having a V-shaped protrusion toward the switching element 10 is integrally formed at a portion of the bus bar 12 facing the switching element 10. The protrusion shape of the contact portion 13 is formed, for example, by bending a flat conductor. The electrode terminal 11 of the switching element 10 is bent in the left direction in the figure, and the tip is disposed between the bus bar 12 and the switching element 10 body. When the resin module 14 is pushed in the direction of the arrow (downward) and assembled and fixed in the ECU housing 5 (see FIG. 1), the bottom surface of the V-shaped tip of the contact portion 13 contacts the top surface of the electrode terminal 11 of the switching element 10. To do. At this time, the contact portion 13 applies a pressing force F in the direction toward the heat sink 9 to the switching element 10.

  Further, when the potentials of the contact portions are different, an insulator such as an insulating sheet is sandwiched between the switching element 10 and the heat sink 9 and between the switching element 10 body and the electrode terminal 11 as necessary, and is electrically insulated from each other. ing. For example, since the thickness of the insulator can be changed to adjust the magnitude of the pressing force F, the adhesion can be further improved.

  Here, the distance D between the lower surface of the opposing resin module 14 and the upper surface of the heat sink 9 is managed to a predetermined dimension. The distance D is set to a value smaller than the sum of the vertical thickness t1 of the switching element 10 and the vertical thickness t2 of the contact portion 13 and the electrode terminal 11 before pressing (D <t1 + t2). . When the resin module 14 is pushed in and assembled and fixed, the contact portion 13 presses the electrode terminal 11 downward. For this reason, when the contact part 13 to be pressed (or the electrode terminal 11 to be pressed) is deformed, the thickness is reduced, and the thickness of the contact part 13m or the electrode terminal 11 after the contact is reduced as a whole. And the switching element 10, the electrode terminal 11, and the contact part 13 are piled up and installed in the distance D set beforehand. The bus bar 12 presses the switching element 10 with the pressing force F, so that the switching element 10 can be securely attached to the heat sink 9.

<Second and Third Embodiments>
Next, the structure around the switching element 10 according to the second and third embodiments will be described.
FIG. 4A is a diagram showing the shape of the contact portion 13 of the bus bar 12 according to the second embodiment of the present invention, and FIG. 4B is the contact portion of the bus bar 12 according to the third embodiment of the present invention. It is a figure which shows the shape of 13.

  As shown in FIGS. 4A and 4B, referring to FIG. 3, the shape of the contact portion 13 that is in contact with the electrode terminal 11 is bent into the V-shaped protrusion shape of the first embodiment. Not limited to things. 4 (a), a contact portion 13 comprising a flat surface obtained by bending the front end portion of the bus bar 12 into a flat plate shape by 180 °, or a contact portion comprising an end face obtained by bending the front end portion of the bus bar 12 in FIG. 4 (b) at a right angle. 13 may be formed.

  As described above, when the switching element 10 is disposed between the bus bar 12 and the heat sink 9, it is effective to form the contact portion 13 at a portion of the bus bar 12 facing the switching element 10. Thereby, when the resin module 14 is fixed, the contact portion 13 formed integrally with the bus bar 12 presses and electrically connects the electrode terminal 11 which is bent and extended of the switching element 10. Furthermore, the switching element 10 and the heat sink 9 can be reliably adhered by the pressing force F applied from the contact portion 13 to the switching element 10.

  Next, operations and effects of the motor control device 3 according to each embodiment of the present invention configured as described above will be described.

  According to the above embodiment, when the switching element 10 is installed between the bus bar 12 and the heat sink 9, the contact portion 13 having a V-shaped protrusion shape at a portion facing the switching element 10 in the bus bar 12. Is formed. The contact portion 13 protrudes from the switching element 10 main body, bends, and presses and contacts the electrode terminal 11 extending between the switching element 10 and the bus bar 12 in the opposing direction. When the resin module 14 in which the bus bar 12 is accommodated is pressed into the ECU housing 5 and fixed, the contact portion 13 presses and electrically connects the electrode terminal 11. At this time, the switching element 10 is pressed against and closely contacts the heat sink 9 by the pressing force F applied from the contact portion 13.

  Moreover, the distance D between the lower surface of the resin module 14 and the upper surface of the heat sink 9 that are opposed to each other is the thickness t1 in the vertical direction of the switching element 10 and the thickness t2 in the vertical direction of the contact portion 13 and the electrode terminal 11 before pressing. It is set to a value smaller than the added value. For this reason, when the resin module 14 is assembled and fixed, the electrode terminal 11 is pressed by the contact portion 13, and the contact portion 13 that presses downward or the pressed electrode terminal 11 is deformed and its thickness decreases. Thereby, the thickness after the contact part 13 and the electrode terminal 11 contact is reduced as a whole. And the switching element 10, the electrode terminal 11, and the contact part 13 are piled up and installed in the distance D set beforehand. The bus bar 12 presses the switching element 10 to securely bring the switching element 10 into close contact with the heat sink 9.

  This eliminates the need for fixing members such as screws and press plates for bringing the switching elements 10 such as FETs and the heat sink 9 into close contact with those used in conventional motor control devices, thereby reducing the number of parts. Can do. Furthermore, since the bus bar 12 and the switching element 10 can be electrically and stably connected without being soldered or welded, a joining step is not required, and the number of assembling steps can be reduced.

  As described above, according to each embodiment of the present invention, it is possible to provide a motor control device capable of reducing the number of parts and the number of assembly steps.

  As mentioned above, although each embodiment which concerns on this invention was described, this invention can also be implemented with another form.

<Other embodiments>
In each of the above embodiments, the case where the heat sink 9 is fixed in the motor housing 4 has been described. However, the present invention is not limited to this. For example, the small heat sink 9 is mounted on the substrate 20 and the switching element 10 It can also be applied to the case where it cools in contact with.

Hereinafter, the structure around the switching element 10 according to another embodiment will be described.
FIG. 5 is a diagram showing a detailed structure of the bus bar 12 and the switching element 10 of a motor control device according to another embodiment of the present invention. For convenience, the same components as those in the first embodiment will be described with the same reference numerals.

  As shown in FIG. 5, the switching element 10 in which the electrode terminal 11 is bent into a V shape is disposed adjacent to the heat sink 9 mounted on the substrate 20. A contact portion 13 having a V-shaped protruding shape toward the switching element 10 is formed at a portion of the bus bar 12 protruding downward from the resin module 14 and facing the switching element 10. When the resin module 14 is pushed in the direction of the arrow (downward) and assembled and fixed to an ECU housing (not shown), the V-shaped tip side surface of the contact portion 13 contacts the side surface of the electrode terminal 11 of the switching element 10. Then, the end portion of the bus bar 12 is brought into contact with and pressed against another electronic component (for example, a connector) 21 mounted on the substrate 20. At this time, the contact portion 13 applies a pressing force F in the direction toward the heat sink 9 to the switching element 10.

  Here, the contact portion 13 may have a tapered tip portion whose diameter decreases toward the direction of the substrate 20 (downward), and may apply the pressing force F to the side surface side of the electrode terminal 11. . Moreover, it may replace with the electronic component 21 and may be made to connect the front-end | tip part of the bus-bar 12 in the direction opposite to a press direction, sharing another board | substrate connection connector. Alternatively, the front end portion of the bus bar 12 may be inserted into a through-hole provided in the substrate 20 and fixed directly.

  According to the above configuration, a fixing member such as a screw or a pressing plate for bringing the switching element 10 such as an FET into close contact with the heat sink 9 becomes unnecessary, so that the number of parts can be reduced. Further, since the bus bar 12 and the switching element 10 can be electrically and stably connected without being soldered or welded, a joining step is not required, and the number of assembling steps can be reduced.

  In each of the above embodiments, the resin module 14 is finally pushed into the ECU housing 5 and assembled and fixed so that the contact portion 13 is pressed and brought into contact. However, the present invention is not limited to this, and the resin module 14 is assembled. After fixing, the heat sink 9 (or the substrate 20) may be assembled by being pushed in from the motor housing 4 side.

  In each said embodiment, although switching element (FET) 10 was illustrated as a cooling object of the heat sink 9, it is not limited to this, The appropriate member mounted in the motor control apparatus 3 is employable.

  In each of the above embodiments, the bus bar 12 is exemplified by a power supply system bus bar that supplies a voltage from the external power supply 6. However, the present invention is not limited to this, and the signal bar bus bar connected between the boards is not limited thereto. Can also be applied.

  In each said embodiment, although the motor apparatus 1 with which the motor main body 2 and the motor control apparatus 3 were integrated was illustrated, it is not limited to this, It applies also to the motor control apparatus isolate | separated from the motor main body. Can do.

  In each of the above embodiments, the cooling structure of the motor control device 3 has been exemplified. However, the present invention is not limited to this, and various electronic devices including a bus bar that is electrically connected and a heat sink that contacts a switching element such as an FET. It can be applied to equipment.

1: Motor device (motor control unit) 2: Motor body
3: motor control device, 4: motor housing, 5: ECU housing, 6: external power supply,
7: Wiring section, 8: Motor output shaft, 9: Heat sink,
10, 10a to 10f: switching element (FET), 11: electrode terminal,
12: bus bar, 13: contact portion, 14: resin module, 15: battery,
16: smoothing capacitor, 17: inverter, 18: power line, 19: ground line, 20: substrate, 21: electronic component,
D: distance between opposing surfaces of the resin module and the heat sink,
t1: thickness of the switching element, t2: thickness of the contact portion and the electrode terminal before pressing,
F: pressing force, m: rotation axis

Claims (3)

A switching element of an inverter for supplying drive voltage to the motor body;
A heat sink that contacts the switching element and emits heat from the switching element;
A bus bar for supplying a voltage from an external power source to the switching element;
A resin module that integrally accommodates the bus bar and is fixed to the housing;
The bus bar has a protruding contact portion that is electrically connected to the electrode terminal of the switching element, and the switching element and the heat sink are in close contact with each other by a pressing force applied from the contact portion. The motor control apparatus characterized by the above-mentioned. The motor control device according to claim 1,
The switching element is disposed between the bus bar and the heat sink, and the contact portion is formed at a portion of the bus bar facing the switching element, and is bent between the resin module and the switching element. A motor control device, wherein the motor control device is in contact with the extending electrode terminal and is pressed in a facing direction. The motor control device according to claim 2,
The distance between the opposing surfaces of the resin module and the heat sink is set to be smaller than a value obtained by adding the thickness of the switching element and the thickness of the contact portion and the electrode terminal before pressing. A motor control device.

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