JP6961990B2 - Motor unit - Google Patents

Description

The present invention relates to a motor unit.

As a conventional motor unit, for example, the technique described in Patent Document 1 is known. The motor unit described in Patent Document 1 includes a rotary electric machine and a control unit integrated with the rotary electric machine to control the drive of the rotary electric machine. The control unit has a power converter that converts a direct current supplied by a direct current power source into an alternating current, a capacitor connected in parallel with the power converter, and an electronic control device that controls the power converter. There is. The power converter has a plurality of power elements and a plurality of freewheeling diodes. The power element is mounted on the frame. A first heat radiation fin is formed on a first surface of the frame opposite to the surface to which the power element is connected. The electronic control device is mounted on a substrate housed in a housing. A second heat radiation fin is formed on the second surface of the housing opposite to the surface to which the electronic control device is connected.

Japanese Unexamined Patent Publication No. 2015-122856

However, in the above-mentioned prior art, the first heat radiation fin and the second heat radiation fin are formed radially around the rotation axis. Therefore, the first heat radiation fin and the second heat radiation fin are arranged over a wide area in the radial direction of the control unit. Further, in the above-mentioned prior art, the arrangement of the capacitor is not particularly considered, but for example, when the capacitor is mounted on the frame together with the power element, if the dimension of the control unit is large with respect to the axial direction of the rotary electric machine. I have no choice but to do it. The above leads to an increase in the size of the control unit (inverter).

An object of the present invention is to provide a motor unit capable of miniaturizing an inverter.

One aspect of the present invention is a motor unit including a motor and an inverter integrated with the motor and controlling the motor. It has a capacitor board that is placed inside the case and mounts a capacitor, and a heat sink that is attached to the motor side surface of the semiconductor board and cools the semiconductor board. The capacitors are arranged in the arrangement direction of the motor and the inverter. It is characterized in that it is mounted on the surface of the capacitor substrate on the motor side so as to face the heat sink in the vertical direction.

In such a motor unit, the semiconductor element is mounted on the semiconductor substrate, and the capacitor is mounted on the capacitor substrate. The semiconductor element here is more likely to generate heat than a capacitor. Therefore, a heat sink for cooling the semiconductor substrate is attached to the surface of the semiconductor substrate on the motor side. At this time, since the heat sink only needs to cool the semiconductor substrate, it is not necessary to increase the size of the heat sink more than necessary. Further, the capacitor is mounted on the surface of the capacitor substrate on the motor side so as to face the heat sink in the direction perpendicular to the arrangement direction of the motor and the inverter. Therefore, it is prevented that the dimensions of the inverter increase in the arrangement direction of the motor and the inverter. As described above, the size of the inverter can be reduced.

A heat radiating member may be arranged between the capacitor and the case. In such a configuration, the heat generated from the capacitor is dissipated to the case by the heat radiating member.

The motor may be equipped with a fan that cools the inverter. In such a configuration, the fan cools the inverter, which in turn cools the heat sink.

The external dimensions of the mounting surfaces of the heat sink and the semiconductor substrate facing each other may be the same. In such a configuration, the external dimensions of the mounting surface of the heat sink can be minimized, so that the dimensions of the heat sink can be reduced.

According to the present invention, the size of the inverter can be reduced.

It is an exploded perspective view which shows the motor unit which concerns on one Embodiment of this invention. It is a schematic cross-sectional view which shows the whole structure of the inverter shown in FIG. It is an enlarged cross-sectional view which shows the fixing structure of the heat sink and a case shown in FIG. It is sectional drawing which shows the flow of the cooling air by the fan shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an exploded perspective view showing a motor unit according to an embodiment of the present invention. In FIG. 1, the motor unit 1 of the present embodiment includes a motor 2 and an inverter 4 that is integrated with the motor 2 via a duct 3 to control the motor 2.

The motor 2 is a three-phase AC motor. The motor 2 has a motor body 32 having a rotor and a stator (see FIG. 4), a motor case 5 accommodating the motor body 32, and three motor terminals 6 drawn from a coil wound around the stator. doing. A fan 7 for cooling the inverter 4 is attached to the motor 2. The fan 7 is attached to the rotating shaft 32a of the motor body 32 by a nut 33 on the inverter 4 side of the motor case 5 (see FIG. 4). A screw to be screwed with the nut 33 is cut on the outer peripheral surface of the tip of the rotating shaft 32a. Therefore, when the motor body 32 rotates, the fan 7 rotates.

The duct 3 covers the portion of the motor case 5 on the inverter 4 side together with the fan 7. The inverter 4 is fixed to the motor 2 via a duct 3 by a plurality of bolts (not shown). The inverter 4 converts a direct current from a battery (not shown) into an alternating current to control the rotational operation of the motor body 32 of the motor 2.

FIG. 2 is a schematic cross-sectional view showing the overall structure of the inverter 4. In FIG. 2, the inverter 4 includes a case 8 made of aluminum. The case 8 is formed of aluminum die casting.

A cover 9 that covers the inside of the case 8 is attached to the side of the case 8 opposite to the motor 2. Further, a battery cable attachment portion 10 to which a battery cable (not shown) electrically connected to the battery (not shown) is attached is fixed to one end of the case 8.

In the case 8, a motor terminal accommodating portion 11 accommodating each motor terminal 6 of the motor 2, a substrate accommodating a MOS (Metal Oxide Semiconductor) substrate 12, a capacitor substrate 13, and a control substrate 14 which are semiconductor substrates are accommodated. A heat sink accommodating portion 17 accommodating a heat sink 16, a heat sink accommodating portion 17 accommodating the heat sink 16, and a capacitor accommodating portion 19 accommodating a capacitor 18 are provided.

The motor terminal accommodating portion 11 is arranged on the other end side of the case 8 (the side opposite to the battery cable mounting portion 10). The board accommodating portion 15 is arranged on the battery cable mounting portion 10 side and the cover 9 side with respect to the motor terminal accommodating portion 11. The heat sink accommodating portion 17 is arranged on the battery cable mounting portion 10 side and on the motor 2 side (opposite side of the cover 9). The capacitor accommodating portion 19 is arranged between the motor terminal accommodating portion 11 and the heat sink accommodating portion 17.

A MOS element 20 which is a semiconductor element is mounted on the MOS substrate 12. The MOS element 20 includes a switching element and the like. The above-mentioned capacitor 18 is mounted on the capacitor board 13. An electronic control component 21 is mounted on the control board 14.

The MOS substrate 12 is fixed to the case 8 by a plurality of bolts 22. The MOS element 20 is mounted on the upper surface 12a (the surface on the cover 9 side) of the MOS substrate 12. Further, a bus bar 24 is attached to the upper surface 12a of the MOS substrate 12 via the terminal 23. The terminal 23 is electrically connected to a terminal (not shown) of the battery. The bus bar 24 is fixed to the heat sink 16 by a plurality of bolts 25 via the terminal 23 and the MOS substrate 12. The bus bar 24 penetrates the wall portion 26 that defines the motor terminal accommodating portion 11 and the substrate accommodating portion 15 and extends to the motor terminal accommodating portion 11 and is connected to the motor terminal 6.

The capacitor substrate 13 is arranged closer to the cover 9 than the MOS substrate 12. That is, the capacitor substrate 13 is arranged on the opposite side of the motor 2 with respect to the MOS substrate 12. Further, the capacitor substrate 13 is arranged so as to be offset from the MOS substrate 12 toward the motor terminal accommodating portion 11. As a result, the MOS substrate 12 and the capacitor substrate 13 can be arranged in the case 8 in a space-efficient manner. The capacitor board 13 is fixed to the case 8 by a plurality of bolts 27. The capacitor 18 is mounted on the lower surface 13b (the surface on the motor 2 side) of the capacitor substrate 13.

The control board 14 is arranged closer to the cover 9 than the capacitor board 13. The control board 14 is fixed to the case 8 by a plurality of bolts 28. The electronic control component 21 is mounted on the upper surface 14a (the surface on the cover 9 side) and the lower surface 14b (the surface on the capacitor substrate 13 side) of the control board 14. Note that FIG. 2 shows only the electronic control component 21 mounted on the lower surface 14b of the control board 14.

The heat sink 16 is attached so as to come into contact with the lower surface 12b (the surface on the motor 2 side) of the MOS substrate 12 to cool the MOS substrate 12. The heat sink 16 is fitted in a part of the case 8. The material of the heat sink 16 is aluminum as in the case 8. As shown in FIG. 3, the heat sink 16 has a plurality of heat radiation fins 29.

The external dimensions of the upper surface 16a (the surface opposite to the motor 2) of the heat sink 16 are the same as the external dimensions of the lower surface 12b of the MOS substrate 12. The term "equivalent" as used herein is a concept that includes not only the case of being completely equal but also the case of being substantially equal. The upper surface 16a of the heat sink 16 and the lower surface 12b of the MOS substrate 12 form mounting surfaces of the heat sink 16 and the MOS substrate 12 facing each other.

The heat sink 16 is formed by extrusion molding. As a result, the pitch of the heat radiating fins 29 can be narrowed and the height of the heat radiating fins 29 can be increased as compared with the case where the heat sink 16 is formed by die casting. As a result, the heat dissipation performance of the heat sink 16 can be improved.

As shown in FIG. 3, the heat sink 16 is fixed to the case 8 by a plurality of bolts 22. At this time, the heat sink 16 is fastened to the case 8 together with the MOS substrate 12 by bolts 22. The heat sink 16 and the MOS substrate 12 do not have to be fastened together with the bolts 22. By using the bolts 22 in this way, a fixed structure between the heat sink 16 and the case 8 can be realized at low cost.

A seal portion 30 is interposed between the heat sink 16 and the case 8. The seal portion 30 is formed of a seal rubber, a liquid sealant, or the like. As a result, the heat sink 16 and the case 8 are sealed.

As described above, the capacitor 18 is mounted on the lower surface 13b of the capacitor substrate 13. Therefore, the capacitor 18 extends to the motor 2 side, that is, to the same side as the heat sink 16. At this time, the capacitor 18 is arranged so as to face the heat sink 16 with the case 8 sandwiched in a direction perpendicular to the arrangement direction (X direction) of the motor 2 and the inverter 4. A heat radiating member 31 that dissipates heat from the capacitor 18 is arranged between the tip surface of the capacitor 18 and the case 8.

In the motor unit 1 as described above, the heat generated from the MOS element 20 is dissipated by the heat sink 16 through the MOS substrate 12, so that the MOS substrate 12 is less likely to become hot. Further, since the heat generated from the capacitor 18 is dissipated to the case 8 by the heat radiating member 31, the capacitor 18 is less likely to become hot.

Further, as shown in FIG. 4, the inverter 4 is cooled by the flow of the cooling air generated by the rotation of the fan 7. In FIG. 4, a part of the inverter 4 is omitted for convenience. At this time, since the heat sink 16 is cooled by the cooling air, the MOS substrate 12 is less likely to become hot. Further, since the portion near the condenser 18 and the heat radiating member 31 in the case 8 are cooled by the cooling air, the condenser 18 is less likely to become hot.

As described above, in the present embodiment, the MOS element 20 is mounted on the MOS substrate 12, and the capacitor 18 is mounted on the capacitor substrate 13. The MOS element 20 is more likely to generate heat than the capacitor 18. Therefore, a heat sink 16 for cooling the MOS substrate 12 is attached to the lower surface 12b of the MOS substrate 12. At this time, since the heat sink 16 only needs to cool the MOS substrate 12, the dimensions of the heat sink 16 need not be made larger than necessary. Further, the capacitor 18 is mounted on the lower surface 13b of the capacitor substrate 13 so as to face the heat sink 16 in a direction perpendicular to the arrangement direction of the motor 2 and the inverter 4. Therefore, it is prevented that the dimensions of the inverter 4 increase in the arrangement direction of the motor 2 and the inverter 4. As described above, the size of the inverter 4 can be reduced.

Further, the case 8 is formed by die casting. Therefore, the degree of freedom in the shape and internal layout of the case 8 is improved. Therefore, the inverter 4 can be further miniaturized.

Further, in the present embodiment, the heat radiating member 31 is arranged between the capacitor 18 and the case 8. Therefore, the heat generated from the capacitor 18 is dissipated to the case 8 by the heat radiating member 31. As a result, the capacitor 18 can be cooled.

Further, in the present embodiment, the motor 2 is equipped with a fan 7 for cooling the inverter 4. Therefore, since the inverter 4 is cooled by the fan 7, the heat sink 16 and the heat radiating member 31 are cooled. As a result, the MOS substrate 12 and the capacitor 18 can be further cooled.

Further, in the present embodiment, the outer dimensions of the upper surface 16a of the heat sink 16 and the lower surface 12b of the MOS substrate 12 are the same. Therefore, since the external dimensions of the upper surface 16a of the heat sink 16 are suppressed to the minimum necessary, the dimensions of the heat sink 16 can be reduced.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the heat sink 16 is fixed to the case 8 by a bolt 22, but the heat sink 16 is not particularly limited to that form, and chemical bonding with an adhesive or the like, or material bonding such as welding or solid phase bonding is performed. You may use it to fix the heat sink 16 to the case 8. In this case, the sealing property between the heat sink 16 and the case 8 can be ensured at the same time as the heat sink 16 and the case 8 are joined. Further, since the bolt 22 and the seal portion 30 are not required, the inverter 4 can be simplified.

Further, in the above embodiment, the external dimensions of the upper surface 16a of the heat sink 16 are the same as the external dimensions of the lower surface 12b of the MOS substrate 12, but the external dimensions are not particularly limited to that form, and the external dimensions of the upper surface 16a of the heat sink 16 are MOS. It may be different from the external dimensions of the lower surface 12b of the substrate 12. Even in this case, since the heat sink 16 only needs to cool the MOS substrate 12, the size of the heat sink 16 can be reduced as compared with the conventional case.

Further, in the above embodiment, the heat sink 16 is attached so as to be in contact with the lower surface 12b of the MOS substrate 12, but the present invention is not particularly limited to that form, and the heat sink 16 has a heat transfer member attached to the lower surface 12b of the MOS substrate 12. It may be attached via.

Further, in the above embodiment, the capacitor substrate 13 is arranged on the opposite side of the motor 2 with respect to the MOS substrate 12, but the embodiment is not particularly limited, and the capacitor substrate 13 is closer to the motor 2 than the MOS substrate 12. It may be arranged in.

1 ... Motor unit, 2 ... Motor, 4 ... Inverter, 7 ... Fan, 8 ... Case, 12 ... MOS substrate (semiconductor substrate), 12b ... Bottom surface (mounting surface), 13 ... Capacitor substrate, 13b ... Bottom surface, 16 ... Heat sink , 16a ... Top surface (mounting surface), 18 ... Capacitor, 20 ... MOS element (semiconductor element), 31 ... Heat dissipation member.

Claims (5)

In a motor unit including a motor and an inverter integrated with the motor and controlling the motor.
The inverter
With the case
A semiconductor substrate arranged in the case and on which a semiconductor element is mounted,
A capacitor board that is placed inside the case and mounts a capacitor,
A heat sink that is attached so as to come into contact with the surface of the semiconductor substrate on the motor side and cools the semiconductor substrate.
Have,
The capacitor is mounted on the surface of the capacitor substrate on the motor side so as to face the heat sink in a direction perpendicular to the arrangement direction of the motor and the inverter.
The heat sink does not project in a direction perpendicular to the arrangement direction of the motor and the inverter with respect to the semiconductor substrate, and has a region overlapping the capacitor substrate in the arrangement direction of the motor and the inverter. , A motor unit characterized in that it does not have a region overlapping the capacitor in the arrangement direction of the motor and the inverter. The heat sink has a main body portion attached so as to come into contact with the surface of the semiconductor substrate on the motor side, and a plurality of heat radiation fins provided on the motor side of the main body portion.
The main body and the heat radiating fin do not project in a direction perpendicular to the arrangement direction of the motor and the inverter with respect to the semiconductor substrate, and overlap the capacitor in the arrangement direction of the motor and the inverter. The motor unit according to claim 1, wherein the motor unit does not have a region. The motor unit according to claim 1 or 2, wherein a heat radiating member is arranged between the capacitor and the case. The motor unit according to any one of claims 1 to 3, wherein a fan for cooling the inverter is attached to the motor. The motor unit according to any one of claims 1 to 4, wherein the external dimensions of the mounting surfaces of the heat sink and the semiconductor substrate facing each other are the same.

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