JP2003339102A - Drive unit for vehicle, and electric power conversion unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive unit for a small sized vehicle having a cooling system with superior cooling performance. <P>SOLUTION: A drive unit includes first and second switching circuits 1A, 1B, first and second motor/generators MG1, MG2. The first and the second motor/generators MG1, MG2 are arranged, in such a manner that the respective axes of rotation 10a, 10b are coaxially positioned, and the first and the second switching circuits 1A, 1B, are positioned between the first motor/generator MG1 and the second motor/generator MG2, and the respective axes of rotation 10a, 10b of the first and the second motor/generator MG1, MG2 are driven and rotated by the energized current. Cooling sections, which are internally provided with cooling paths 20a<SB>1</SB>, 20b<SB>1</SB>through which coolant is circulated, are positioned on the first motor/generator MG1 side of the first switching circuit 1A, and the second motor/generator MG2 side of the second switching circuit 1B, respectively. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion unit incorporating a switching circuit for reversely converting AC power into DC power, and for a vehicle including an electric motor driven by the power supplied by the switching circuit. A drive device.

[0002]

2. Description of the Related Art Conventionally, DC power obtained from a DC power supply is converted into AC power using a power converter, and an electric motor is driven using this AC power to efficiently convert electrical energy into kinetic energy. Electric drives are known. The electric drive device has a wide range of applications, and in recent years, some of the electric drive devices have been put into practical use when mounted on vehicles.

Vehicles equipped with the above electric drive system include hybrid electric vehicles equipped with an electric drive system in addition to the engine, and electric vehicles equipped with only the electric drive system without an internal combustion engine. There is an electric vehicle. These vehicles are attracting attention as environmentally friendly vehicles.

In such an electric drive apparatus, a switching circuit for converting DC power supplied from a battery into AC power and a magnetic force of a stator generated by the AC power supplied from the switching circuit are used to rotate a rotor (rotation). It is mainly composed of an electric motor, which is an electric motor driven by rotation of a child.

In mounting the electric drive device on a vehicle, it is necessary to arrange the electric drive device in a limited space, and it is essential to downsize the device. Particularly in a hybrid electric vehicle, it is necessary to arrange an engine and an electric motor in a limited space, and miniaturization of each device is a very important issue. At the same time, since the electric motor and the switching circuit are heat-generating components, it is necessary to cool them in order to prevent damage due to heat accumulation. For this reason, designing the cooling system and downsizing the cooling system are also important issues.

As the cooling system of the electric drive device, an air cooling type cooling system and a liquid cooling type cooling system can be considered. In order to enhance the habitability in the vehicle, it is preferable to use a liquid cooling type cooling system that does not require a large heat dissipation area. An example of a vehicle drive device that employs this liquid cooling system is a vehicle drive device disclosed in Japanese Patent Laid-Open No. 7-288950.

FIG. 9 is an axial sectional view showing a main part of the vehicle drive device disclosed in the above publication. As shown in the figure, in the vehicle drive device described in the above publication, a switching circuit is included in the axial end surface of one of the two electric motors M1 and M2 arranged coaxially. The switching module 107 is disposed, and the heat dissipation portion 107a of the switching module 107 is disposed.
The cooling path 120b ₁ through which the refrigerant flows is formed between the electric motor M2 and the axial end surface of the electric motor M2. The switching element that constitutes the switching circuit is mounted on the heat dissipation portion 107a in the switching module 107,
It is cooled by the cooling path 120b ₁ via the heat dissipation portion 107a. As a result, the cooling path of the cooling system can be shortened, and the vehicle drive device including the cooling system can be downsized.

However, the following problems may occur in the vehicle drive device having the above structure.

First, when the above structure is adopted, there is a possibility that sufficient cooling performance cannot be obtained. Usually, a plurality of switching elements and a free wheel diode, which is a freewheeling diode, are mounted inside the switching module, and the area of the cooling surface thereof tends to increase as the rated current of the switching module increases. As a switching module used in a vehicle drive device, a switching module having a very high rated current of several tens A to several thousands A is usually required, and thus a cooling surface having a very large area is required. Therefore, the switching module for driving the two electric motors M1 and M2 is so large that it cannot be arranged on the end surface in the axial direction of one electric motor M2. Even if they can be arranged, it is difficult to secure a sufficiently large heat dissipation area for the heat generated in the switching element, and it is expected that the cooling performance will be poor.

Second, when a power split / transmission means such as a planetary gear or a chain drive sprocket is arranged between the two electric motors M1 and M2, a switching module is actually arranged more than that shown in the drawing. The area is expected to be smaller. Therefore, in the above structure, the heat dissipation area is further narrowed, and it is difficult to obtain sufficient cooling performance.

As described above, it is expected that it will be difficult to obtain sufficient cooling performance with the structure disclosed in the above publication, and further improvement is required.

As a vehicle drive device that solves this problem, a vehicle drive device having the structure shown in FIG. 10 can be considered.
In the vehicle drive device shown in FIG. 10, the switching module 207 is arranged on the outer peripheral surface of the housing of the two electric motors M1 and M2 (that is, the surface surrounding the rotary shaft in the direction parallel to the axis of the rotary shaft). It Normally, the area of the outer peripheral surface of the housing of the electric motor is larger than the area of the end surface in the axial direction, and the switching module 207 is provided on this outer peripheral surface.
By arranging, it becomes possible to secure a large heat dissipation area. A cooling path through which the refrigerant flows is formed between the switching module 207 and the outer peripheral surfaces of the housings of the electric motors M1 and M2, as in the vehicle drive device disclosed in the above publication. The electric motors M1 and M2 are the bus bars 2
It is electrically connected by 08.

Further, in order to reduce the size of the vehicle drive device as a whole, as shown in FIG. 11, an electric motor M is used.
It is effective to dispose the smoothing capacitor 206 between 1 and M2. In this way, the two electric motors M1,
By disposing the smoothing capacitor 206 between M2, it is possible to shorten the bus bar 208 that electrically connects the switching module 207 and the smoothing capacitor 206. As a result, the surge applied to the switching element forming the switching circuit is reduced, and the power loss in the wiring is also reduced, so that it is possible to provide a small-sized and high-performance vehicle drive device.

However, in the vehicle drive device of this configuration, since the vehicle drive device becomes large in the radial direction of the rotation shaft, it still contributes sufficiently to the downsizing of the vehicle drive device as a whole. I haven't.

[0015]

SUMMARY OF THE INVENTION Therefore, the present invention has been made to solve the above-mentioned problems, and is used for a small-sized vehicle drive device having a cooling system having excellent cooling performance and the vehicle drive device. It is an object of the present invention to provide a power conversion unit that can be used.

[0016]

A vehicle drive device according to the present invention comprises a switching circuit and two first and second electric motors. The first and second electric motors are arranged such that their rotation axes are coaxially located. The switching circuit is located between the first electric motor and the second electric motor,
Each of the rotating shafts of the first and second electric motors is rotationally driven by the energized current. The cooling unit including therein a passage through which the refrigerant flows is provided on the first motor side of the switching circuit and the second motor side.
It is located on each side of the electric motor.

As described above, by disposing the switching circuit between the first electric motor and the second electric motor and by disposing the cooling unit on each of the first electric motor side and the second electric motor side of the switching circuit, a large cooling area can be obtained. Can be secured. This makes it possible to provide a vehicle drive device having excellent cooling performance. Further, since the switching circuit is arranged between the first and second electric motors, the overall size of the device can be reduced. Therefore, it is possible to achieve both the downsizing of the vehicle drive device and the improvement of cooling efficiency.

In the vehicle drive apparatus according to the present invention, the switching circuit drives the first electric motor.
A cooling circuit including a switching circuit and a second switching circuit for driving the second electric motor, wherein each cooling unit is located on the first electric motor side of the first switching circuit and the second electric motor side of the second switching circuit. desirable.

As described above, the first switching circuit for driving the first electric motor is arranged on the first electric motor side, and the second switching circuit for driving the second electric motor is arranged on the second electric motor side to connect them. Wiring can be shortened, which contributes to downsizing of the entire device and reduction of loss, and a high-performance vehicle drive device can be configured compactly.

Each of the first and second switching circuits includes a switching element and a heat radiating portion that radiates heat generated by the operation of these switching elements to the outside. In the vehicle drive device according to the present invention, it is desirable that the first and second switching circuits are arranged so that the respective heat radiation parts come into contact with the respective cooling parts.

As described above, by disposing the heat radiating portion and the cooling portion in direct contact with each other, it is possible to provide a vehicle drive device having further excellent cooling performance.

In the vehicle drive device according to the present invention, the first switching element control circuit for controlling the operation of the switching element forming the first switching circuit,
A second switching element control circuit for controlling the operation of a switching element that constitutes the second switching circuit,
It is preferable that the first switching element control circuit and the second switching element control circuit are formed on a single printed circuit board arranged between the first and second switching circuits.

As described above, the first and second switching element control circuits for controlling the ON / OFF operation of the switching elements which form the first and second switching circuits for supplying electric power to the first and second electric motors are provided as a single unit. By forming it on the printed circuit board and sharing the printed circuit board, it is possible to reduce the size of the vehicle drive device in the axial direction.

In the vehicle drive device according to the present invention, for example, the first switching element control circuit is formed on the surface of the printed circuit board on the first switching circuit side, and the second switching element control circuit is formed on the printed circuit board. 2 It is desirable to be formed on the surface of the switching circuit side.

By thus forming the circuits on both main surfaces of the printed board, it becomes possible to form the first and second switching element control circuits with high density, and these circuits are formed on a single board. It becomes possible to share.

In the above vehicle drive device according to the present invention, it is desirable that each cooling portion is formed by opposing walls of the housings of the first and second electric motors that face each other.

As the position where the cooling section is provided,
Opposing opposing walls of the housings of the first and second electric motors are conceivable. By providing a passage through which the refrigerant flows in each of the opposing walls of these housings, it becomes possible to cool the first and second switching circuits with high efficiency.

The vehicle drive device according to the present invention further includes a housing that houses the first and second switching circuits therein and has an outer wall surface and an inner wall surface, and the heat radiating portions of the housings face each other. To contact the inner wall surfaces of the first
It is preferable that the housing is arranged such that the second switching circuit and the second switching circuit are respectively arranged, and the outer wall surfaces corresponding to the pair of inner wall surfaces come into contact with the facing wall surfaces of the first and second electric motors, respectively.

As described above, it is possible to house the first and second switching circuits in the housing to form a unit. In this case, the first and second switching circuits are arranged on a pair of inner wall surfaces facing each other of the inner wall surfaces of the housing, and contact the outer wall surfaces corresponding to the pair of inner wall surfaces. The first and second electric motors are arranged so as to sandwich the housing. As a result, heat can be exchanged between the heat radiating portion and the cooling portion via the wall of the housing, so that the switching circuit can be efficiently cooled. This unitization improves workability during manufacturing. Further, even when the switching circuit is repaired or replaced, the switching circuit can be taken out together with the unit, so that the maintenance work can be simplified.

In the vehicular drive system according to the present invention, it is preferable that each cooling section is constituted by the wall of the housing.

As a position where the cooling unit is provided,
A wall of the housing in which the first and second switching circuits are housed is conceivable. By forming a path through which the refrigerant flows in the wall of the housing that houses the first and second switching circuits, the distance between the switching element and the refrigerant can be shortened,
It becomes possible to cool with high efficiency.

A power conversion unit according to the present invention comprises a first
And a second switching circuit and a housing that houses these circuits therein. The power conversion unit is arranged so as to be interposed between the first and second electric motors arranged coaxially. Each of the first and second switching circuits includes a switching element and a heat radiation section that radiates heat generated by the operation of these switching elements to the outside. The first and second switching circuits are arranged such that their respective heat radiation portions are in contact with the inner wall surface of the inner wall surface of the housing located on the first electric motor side and the inner wall surface of the second electric motor side. To be done.

In this way, by arranging the first and second switching circuits respectively on the pair of inner wall surfaces located on the two electric motor side among the inner wall surfaces of the housing, the two are arranged coaxially. By disposing the power conversion unit between the two electric motors, it becomes possible to easily manufacture the vehicle drive device.

In the power conversion unit according to the present invention, the operation of the first switching element control circuit for controlling the operation of the switching element forming the first switching circuit and the operation of the switching element forming the second switching circuit are performed. A second switching element control circuit for controlling, wherein the first switching element control circuit and the second switching element control circuit are formed on a single printed circuit board arranged between the first and second switching circuits. Preferably.

As described above, the first and second switching element control circuits for controlling the ON / OFF operation of the switching elements which form the first and second switching circuits for supplying electric power to the first and second electric motors are provided as a single unit. By forming the power conversion unit on the printed circuit board and sharing the printed circuit board, the power conversion unit can be downsized.

In the power conversion unit according to the present invention, the first switching element control circuit is formed on the surface of the printed board on the first switching circuit side, and the second switching element control circuit is the second switching circuit of the printed board. It is preferably formed on the side surface.

By forming the circuits on both main surfaces of the printed circuit board in this manner, it becomes possible to form the first and second switching element control circuits at a high density, and these circuits are formed on a single board. It becomes possible to share.

In the power conversion unit according to the present invention, it is preferable that each cooling section is formed by the wall of the housing.

As described above, by providing the passage for the refrigerant in the wall of the casing in which the first and second switching circuits are arranged and forming the cooling unit by the wall of the casing itself, the first portion can be efficiently transferred. And it becomes possible to provide the power conversion unit which can cool the switching element which comprises a 2nd switching circuit.

In the power conversion unit according to the present invention, it is preferable that a smoothing capacitor for smoothing the power supplied to the first and second switching circuits is further housed in the housing. .

Since the smoothing capacitor is housed inside the housing as described above, the connection between the first and second switching circuits and the smoothing capacitor can be shortened, so that the loss is reduced. It becomes possible to suppress. Further, by disposing the smoothing capacitor in the dead space inside the housing, it becomes possible to downsize the vehicle drive device.

[0042]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is an axial sectional view of a vehicle drive unit according to Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
FIG. 3 is a circuit configuration diagram of the vehicle drive device according to the first embodiment of the present invention.

First, with reference to FIG. 1, the structure of the vehicle drive device in the present embodiment will be described. As shown in the figure, the vehicle drive device includes two motors / generators MG1 and MG2, and those motors / generators MG2.
1 and MG2, and a power conversion unit IU that houses two switching circuits.

Two motors / generators MG1, MG
Reference numeral 2 has rotating shafts 10a and 10b, respectively, and they are arranged so that their rotating shafts are coaxially overlapped. motor/
A planetary gear 31 and a chain drive sprocket 32, which are power splitting / transmitting means, and the above-described power conversion unit IU are arranged between the generators MG1 and MG2.

The motor / generator MG1 includes a housing 20a, a rotating shaft 10a, a stator core 11a, and
The coil 12a, the rotor 13a, and the permanent magnet 14a are mainly included. The stator core 11a includes the housing 2
0a is fitted and fixed to the inner peripheral surface of the coil 1
2a is wound around the stator core 11a. The rotor 13a is fixed to the rotating shaft 10a so as to be located in the inner peripheral region of the stator core 11a via a radial gap, and the permanent magnet 14a is mounted in the rotor 13a. The rotary shaft 10a has a rolling bearing 19
It is rotatably supported by the housing 20a via.

The motor / generator MG2 includes a housing 20b, a rotary shaft 10b, a stator core 11b, and
The coil 12b, the rotor 13b, and the permanent magnet 14b are mainly included. Since these configurations are almost the same as the configurations of the respective parts of the motor / generator MG1, the description thereof will be omitted. The rotary shaft 10 to which the rotor 13b is fixed
b is also rotatably supported by the housing 20b via the rolling bearing 19.

As described above, the power conversion unit IU has two units.
It is arranged between two motor / generators MG1, MG2. At this time, the power conversion unit IU is arranged so that the axial end surface of the inverter case 20c, which is the casing of the power conversion unit IU, contacts the mutually facing wall surfaces of the housings 20a, 20b of the motor / generators MG1, MG2. It The power conversion unit IU
Has a shape that avoids the planetary gear 31 and the chain drive sprocket 32 described above.

First and second switching circuits 1A, 1
Each of B has a switching element 1a, a freewheel diode 1b, and a heat dissipation portion 1c. Switching element 1a and freewheel diode 1
b is mounted on the heat dissipation portion 1c. As described above, by mounting the switching element 1a and the freewheel diode 1b on the heat radiating portion 1c, the heat generated in the element by the operation of the element is radiated to the outside. Here, for the heat radiating portion 1c, for example, a ceramic substrate or the like whose both surfaces are plated with copper is used.

In the power conversion unit IU, two first and second switching circuits 1A and 1B are arranged. First, the motor / generator M is attached to the inner wall surface of the inverter case 20c on the motor / generator MG1 side.
A first switching circuit 1A for driving G1 is arranged. On the other hand, a second switching circuit 1B for driving motor / generator MG2 is arranged on the inner wall surface of inverter case 20c on the side of motor / generator MG2. As a result, the switching elements and the like forming the first switching circuit 1A and the second switching circuit 1
The switching element and the like forming B are arranged on the pair of inner wall surfaces in the inverter case 20c so as to face each other.

Near the center of the accommodation space inside the inverter case 20c (that is, the first switching circuit 1A and the second switching circuit 1A).
A printed circuit board 2 is disposed between the switching circuits 1B), and its main surface faces the rotation shafts 10a, 10b of the motor / generators MG1, MG2 so as to face the first and second switching circuits 1A, 1B. It is oriented in the stretching direction. A switching element control circuit that controls the operation of the switching element of the first switching circuit 1A and a switching element control circuit that controls the operation of the switching element of the second switching circuit 1B are shared on the printed circuit board 2. Has been formed. That is, two switching element control circuits are formed on the single printed circuit board 2. In this case, the first switching circuit 1
A first switching element control circuit for controlling the switching element forming A is formed on the main surface of the printed circuit board 2 on the first switching circuit 1A side, and the second switching circuit 1
It is preferable that the second switching element control circuit that controls the switching element that constitutes B is formed on the main surface of the printed circuit board 2 on the second switching circuit 1B side. The gate output terminal of the printed board 2 is electrically connected to the gate electrode of the switching element 1a by the signal line 3.

Next, with reference to FIGS. 1 and 2, the cooling structure of the vehicle drive device according to the present embodiment will be described. As shown in FIG. 1, the motor / generator MG2
A pump 17 that sends out the refrigerant is installed on the end face of the axial end face of the one that does not face the power conversion unit IU. The refrigerant sent out by the pump 17 flows through the cooling path 10b ₁ formed in the rotating shaft 10b of the motor / generator MG2. The rotation shaft 10b of the motor / generator MG2 is provided with a refrigerant ejection hole. As a result, a part of the refrigerant is ejected from the ejection hole into the housing 20b of the motor / generator MG2.

The wall forming the end surface of the housing 20b of the motor / generator MG2 on the side facing the power conversion unit IU has a cooling path 20b ₁ through which the refrigerant flows. The cooling path 20b ₁ is connected to the cooling path 10b ₁ of the rotary shaft 10b, the refrigerant is supplied from the cooling path 10b _1. As a result, the wall of the housing of the motor / generator MG2 serves as a second cooling unit that absorbs the heat of the heat radiation unit 1c of the second switching circuit 1B.
It is configured on the motor / generator MG2 side of the switching circuit 1B.

Here, as shown in FIG.
b _1, the refrigerant flowing from the cooling passages 10b ₁ of the rotary shaft 10b is arranged to move radially outward by rotating spirally. In addition, in FIG. 1, in order to clearly explain the moving direction of the refrigerant, the illustration of the partition wall forming the cooling path is omitted. Further, in FIG. 2, the illustration of the rotary shaft is omitted. The refrigerant that has circulated in the cooling path 20b ₁ is recovered by the circulation hole 21, passes through the inside of the stator 11b of the motor / generator MG2, and reaches the cooling oil chamber 18b (see FIG. 1).

Further, the pump 17 allows the motor / generator to be
Cooling path 10b in rotating shaft 10b of the generator MG2₁To
A part of the delivered refrigerant is a motor / generator MG.
Cooling path 10a formed in the rotating shaft 10a of No. 1₁To
To reach. Motor / generator MG1 housing 2
The end surface of the power conversion unit IU on the side facing the power conversion unit IU
The wall is a cooling path 20a through which the refrigerant flows.₁Have
ing. This cooling path 20a₁Is the cooling of the rotating shaft 10a
Route 10a₁Is connected to the cooling path 10a ₁Cold from
The medium is supplied. As a result, the motor / generator
First switching by the wall of the housing of the MG1
The cooling unit that absorbs the heat of the heat radiation unit 1c of the circuit 1A is the first switch.
On the motor / generator MG1 side of the switching circuit 1A
Will be configured. In addition, this cooling path 20a
₁Is formed on the wall of the motor / generator MG1.
Cooling path 20b₁It is a cooling path of the same shape as. This
Inside the cooling path of 20a₁The refrigerant flowing through the
The cooling oil passes through the inside of the stator 11a of the nebulator MG1.
It reaches the chamber 18a.

In this embodiment, the motor /
The generator MG1 is a motor / generator having a smaller rated current than the motor / generator MG2 and is used as an auxiliary machine for driving the vehicle. Therefore, the refrigerant is not introduced into the housing 20a of the motor / generator MG1. Although not provided, it may be configured to eject into the housing similarly to the motor / generator MG2 which is the main machine.

As described above, the cooling passage through which the refrigerant flows is formed in the wall of the housing which constitutes the axial end faces of the two motor / generators on the side of the power conversion unit, so that the refrigerant flowing through the cooling passage can be The switching element located in the power conversion unit is effectively cooled.

Next, with reference to FIG. 3, the circuit configuration of the vehicle drive device according to the first embodiment of the present invention will be described.

The circuit shown in FIG. 3 is a circuit configuration of a general vehicle drive device, and the vehicle drive device according to the embodiment of the present invention also employs this circuit configuration. The switching circuit 1 has a set of a switching element 1a and a freewheel diode 1b for three upper and lower arms, that is, a total of six sets. The switching circuit 1 is configured by configuring the three-phase bridge circuit by the six sets of switching elements 1a and the freewheel diode 1b. As a result, it becomes possible to convert the DC power into three-phase AC power and output the AC power in accordance with the input signal.

Here, as the switching element 1a,
An insulated gate field effect transistor such as an IGBT (Insulated Gate Bipolar Transistor) or a power MOS (Metal Oxide Semiconductor) transistor is used. The freewheel diode 1b is a diode element used for freewheeling.

Each gate of the switching element 1a has
It is connected to the switching element control circuit 4. The switching element control circuit 4 also includes an ECU (Electrical Controller) (not shown) via an inverter control circuit (not shown).
ol Unit) and controls the ON / OFF operation of the switching element 1a according to the operating conditions of the vehicle.
Note that in recent years, in consideration of mountability in a vehicle drive device, an IPM (In) in which a switching element and a switching element control circuit are simultaneously mounted in a single package.
A module 7 called an integrated power module) is the mainstream.

The IPM 7 including the switching circuit 1 and the switching element control circuit 4 has two terminals P and N on the DC power input side as connecting terminals to the outside.
The AC power output side has three terminals U, V, and W. Of these, the P and N terminals are electrically connected to the positive and negative electrodes of the battery Batt and the smoothing capacitor 6, respectively. Here, the smoothing capacitor 6 is a capacitor that smoothes the DC power input to the switching circuit 1. On the other hand, the U, V, W terminals are respectively connected to the three-phase connection terminals of the motor / generator MG.

With the above configuration, the DC power obtained from the battery Batt is turned on / off by the switching element 1a.
It is converted into AC power by the F operation, and the three-phase (U-phase, V-phase, W-phase) AC power obtained by the conversion causes the motor /
The generator MG is driven. This allows the motor /
A rotating force that is a propulsive force of the vehicle is applied to the rotating shaft of the generator MG.

In the vehicle drive device according to the present embodiment, the two switching circuits are arranged between the two motors / generators, and the cooling unit is arranged on the motor / generator side of the switching circuits.
The cooling area is twice as large as that of the conventional vehicle drive device. This makes it possible to cool the switching element efficiently. Further, since the two switching circuits are arranged between the two motors / generators, downsizing of the entire device can be realized. Therefore, it is possible to achieve both the downsizing of the vehicle drive device and the improvement of cooling efficiency.

Further, in the present embodiment, the printed board on which the switching element control circuit for driving the two switching circuits is formed is shared by a single board. As a result, the size of the vehicle drive device in the axial direction can be made smaller than in the conventional case.

Further, in the present embodiment, the two switching circuits are housed in the housing to be unitized, so that the easiness of the work at the time of manufacturing or repair is secured.

(Second Embodiment) FIG. 4 is an axial sectional view of a vehicle drive device according to a second embodiment of the present invention.
The vehicle drive device according to the present embodiment is the one in which the configuration of the cooling path according to the first embodiment is changed.
Therefore, the same parts as those in the first embodiment are designated by the same reference numerals in the drawings, and the description thereof will not be repeated.

In the vehicle drive device of the present embodiment, inverter case 20 of power conversion unit IU arranged between motor / generators MG1 and MG2.
A cooling path through which the refrigerant flows is also formed on the wall of c.
As a result, the wall of the inverter case 20c constitutes a cooling unit that absorbs the heat of the heat radiation unit 1c of the switching circuits 1A and 1B on the motor / generator MG1 and MG2 sides of the switching circuits 1A and 1B. The cooling path 20c ₁ formed in the wall of the inverter case 20c of the power conversion unit IU and the housings 20a, 20 of the motor / generators MG1, MG2, respectively.
The cooling paths 20a ₁ and 20b ₁ formed in b communicate with each other.

The refrigerant flowing in from the refrigerant inflow hole 20c ₂ provided in the peripheral surface of the inverter case 20c is supplied to the wall of the inverter case 20c on the side of the motor / generator MG1 and the motor / generator M of the inverter case 20c.
It branches and circulates to the cooling path 20c ₁ formed on each of the G2 side walls. The heat dissipation 1c of the first and second switching circuits 1A and 1B is respectively formed on the inner wall surface of the inverter case 20c where the cooling path 20c ₁ is formed.
Since the parts are arranged, the heat generated in the switching element is absorbed by the refrigerant flowing in the cooling path 20c ₁ .

The coolant flowing through the cooling path 20c ₁ located on the motor / generator MG1 side flows into the cooling path 20a ₁ in the wall of the motor / generator MG1. A part of the refrigerant flowing through the cooling path 20a ₁ in the wall of the motor / generator MG1 flows through the stator 11a of the motor / generator MG1 and is collected in the cooling oil chamber 18a. Cooling path 2 in the wall of motor / generator MG2
The remaining refrigerant branched in 0a ₁ passes through the inside of the housing 20a of the motor / generator MG1 and passes through the rotary shaft 10
It reaches the cooling path 20a ₁ formed in a ₁ and flows out of the vehicle drive device.

On the other hand, the refrigerant flowing through the cooling path 20c ₁ located on the motor / generator MG2 side flows into the cooling path 20b ₁ in the wall of the motor / generator MG2. Cooling path 2 in the wall surface of motor / generator MG2
A part of the refrigerant flowing through 0b ₁ flows through the stator 11b of the motor / generator MG2 and is collected in the cooling oil chamber 18b. The remaining refrigerant branched in the cooling path 20b ₁ in the wall surface of the motor / generator MG2 passes through the housing 20b of the motor / generator MG2 and reaches the cooling path 20b ₁ formed in the rotating shaft 10b ₁ .
Part of it is ejected from the ejection hole into the housing 20b,
The rest flows out of the vehicle drive system.

In the present embodiment, the cooling passage through which the refrigerant flows is formed in the wall of the inverter case of the power conversion unit, and further on the cooling passage through which the refrigerant flows,
The heat dissipation part of the switching circuit is located upstream of the motor / generator. Therefore, the first embodiment described above
It becomes possible to cool the switching circuit more effectively than that.

(Third Embodiment) FIG. 5 is an axial sectional view of a vehicle drive device according to a third embodiment of the present invention.
In the vehicle drive device of the present embodiment, the cooling unit that comes into contact with the heat dissipation unit to cool is formed separately from the motor / generator and the inverter case. In addition,
The same parts as those in the first and second embodiments are designated by the same reference numerals in the drawings, and the description thereof will not be repeated.

In the vehicle drive device of the present embodiment, a separate body is provided between the motor / generators MG1 and MG2 and the wall surface of the inverter case 20c of the power conversion unit IU arranged therebetween. The cooling member CM is arranged. As the separate cooling member CM, for example, two disk-shaped members in which a cooling path through which a refrigerant flows are formed are used. As a result, the cooling unit that absorbs the heat of the heat radiation unit 1c of the switching circuits 1A and 1B is
The motor / generators MG1 and MG2 of the switching circuits 1A and 1B are provided via the wall surface of the inverter case 20c.
Will be configured on the side.

The refrigerant flowing from the refrigerant inflow hole 20d ₂ provided on the peripheral surface of the cooling member CM circulates in the cooling path 20d ₁ formed in the cooling member CM, and the other peripheral surface of the cooling member CM. Flows out to the outside from the outflow hole 20d ₃ formed in the area. Here, since each cooling member CM is in contact with the wall surface of the inverter case 20c in which the heat dissipation portion 1c on which the switching element is mounted is assembled, heat generated in the switching element by the refrigerant flowing through the cooling member CM is generated. It becomes possible to absorb heat. Motor / generators MG1 and MG2 have the same cooling paths as those in the first embodiment.

In this embodiment, since the cooling member is arranged so as to contact the end surface in the axial direction of the power conversion unit, the heat of the heat radiating section arranged in the power conversion unit is the same as that of the power conversion unit. Heat is absorbed by the refrigerant flowing through the cooling member via the wall surface. On the other hand, the motor / generator is cooled by a cooling path formed separately from the cooling path constituted by a separate cooling member. As described above, in the present embodiment, since the cooling paths for cooling the switching circuit and the motor / generator are provided independently of each other, it becomes possible to cool each heat generating element more effectively. Even in this case, the configuration as in the present embodiment realizes the downsizing of the entire device, so that it is possible to achieve both the downsizing of the vehicle drive device and the improvement of the cooling efficiency.

In the first to third embodiments described above, FIG.
As shown in FIG. 2, the power conversion unit IU has a structure in which the switching circuits 1A and 1B are directly arranged on a pair of inner wall surfaces of the inverter case 20c via a heat dissipation portion formed of a copper-clad substrate or the like. ing. However, a package called IPM is often used as the configuration of the power conversion unit. Hereinafter, a configuration example of a power conversion unit when an IPM is used as the power conversion unit according to the present invention will be described.

First, as shown in FIG. 7, the IPM 7 may be arranged on a pair of inner wall surfaces of the inverter case 20c. Here, the IPM also includes a printed circuit board on which a switching element control circuit is formed together with a switching element and a freewheel diode in a single package as described above, and a heat dissipation part is provided on the lower surface thereof. A heat radiating plate 7a is arranged. By disposing the heat radiating portion 7a so as to be in contact with the pair of inner wall surfaces of the inverter case 20c, it becomes possible to configure the power conversion unit applicable to the vehicle drive device described above.

Further, as shown in FIG. 8, it is possible to use a power conversion unit in which the smoothing capacitor 6 is housed in the inverter case 20c. In the inverter case 20c, the IPM 7 and the smoothing capacitor 6 are connected by the bus bar 8. By accommodating the smoothing capacitor 6 in the inverter case 20c as in this configuration, the bus bar 8 that electrically connects the switching circuits 1A and 1B and the smoothing capacitor 6 can be shortened. While reducing the surge applied to the switching elements that make up the switching circuit,
Since the power loss in the wiring is also reduced, it is possible to provide a compact and high-performance power conversion unit.

In the above-described first to third embodiments, as a configuration example in which the cooling unit is arranged on the electric motor side of the switching circuit, when the cooling unit is formed by the wall of the housing of the electric motor, The case where it is formed by a wall and the case where a separate cooling member is interposed between the electric motor and the power conversion unit are illustrated respectively, but the crawling of the cooling path and the circulation direction of the refrigerant in these cases are to the last. It is exemplary and not limiting. The present invention is intended to increase the heat radiation area of a switching circuit while maintaining the miniaturization of the entire vehicle drive device,
In the vehicle drive device in which the switching circuit is arranged between the two electric motors, any structure may be adopted as long as the cooling unit is arranged on each of the electric motor sides of the switching circuit as described above. Absent.

Further, in each of the above-described first to third embodiments, the case where the inverter case which is the housing containing the first and second switching circuits is provided has been described as an example. Cases are not always an essential component. For example, the IPM may be placed in direct contact with the wall of the motor housing.

Further, in the above-described first to third embodiments, description has been given by exemplifying the case where the first and second switching circuits are arranged on the wall surface side of the electric motors respectively driven, but the present invention is not particularly limited to this. It is not something that will be done. For example, the first switching circuit that drives the first electric motor may be arranged on the second electric motor side.

As described above, the above-described embodiments disclosed this time are exemplifications in all respects, and are not restrictive. The technical scope of the present invention is defined by the claims, and includes the meaning equivalent to the description of the claims and all modifications within the scope.

[0084]

According to the present invention, the two coaxially arranged
Even if a switching circuit for driving these electric motors is arranged between two electric motors, a large cooling area can be ensured. Therefore, a small-sized vehicle drive device having a cooling system with excellent cooling performance and this vehicle It becomes possible to provide the electric power conversion unit used for the drive device for automobile.

[Brief description of drawings]

FIG. 1 is an axial sectional view of a vehicle drive device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a diagram showing a circuit configuration of an electric drive device.

FIG. 4 is an axial cross-sectional view of a vehicle drive device according to a second embodiment of the present invention.

FIG. 5 is an axial cross-sectional view of a vehicle drive device according to a third embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view showing the structure of the power conversion unit according to the first to third embodiments of the present invention.

FIG. 7 is a schematic cross-sectional view showing another example of the power conversion unit based on the present invention.

FIG. 8 is a schematic cross-sectional view showing still another example of the power conversion unit according to the present invention.

FIG. 9 is an axial cross-sectional view of a vehicle drive device in a conventional example.

FIG. 10 is a schematic perspective view of a vehicle drive device in another conventional example.

FIG. 11 is a schematic perspective view of a vehicle drive device according to still another conventional example.

[Explanation of symbols]

1 switching circuit, 1A first switching circuit,
1B 2nd switching circuit, 1a switching element, 1b freewheel diode, 1c heat dissipation part,
2 printed circuit boards, 3 signal lines, 4 switching element control circuits, 6 smoothing capacitors, 7 IPMs (switching modules), 7a heat dissipation part, 8 bus bars, 10
a, 10b rotating shaft, 10a ₁ , 10b ₁ cooling path, 1
1a, 11b stator core, 12a, 12b coil, 13a, 13b rotor, 14a, 14b permanent magnet, 17 pump, 18a, 18b cooling oil chamber, 20
a, 20b housing, 20c inverter case,
20d cooler, 20a ₁ , 20b ₁ , 20c ₁ , 20d ₁
Cooling path, 20c _2, 20d ₂ inlet, 20d ₃ outflow hole, 21 hole, 31 planetary gear, 32 a chain drive sprocket, Batt battery, C
M cooling member, IU power conversion unit, MG1, MG
2 Motor / generator.

Claims (13)

[Claims] 1. A switching circuit and first and second electric motors each having a rotary shaft that can be rotationally driven by a current supplied from the switching circuit, wherein the first and second electric motors are the respective rotary shafts. Are arranged so as to be coaxial with each other, and the switching circuit includes the first
A vehicle drive device arranged between an electric motor and the second electric motor, wherein a passage through which a refrigerant flows is provided inside each of the first electric motor side and the second electric motor side of the switching circuit. A vehicle drive unit in which the cooling unit is located. 2. The switching circuit includes a first switching circuit which drives the first electric motor and a second switching circuit which drives the second electric motor, and the first electric motor side of the first switching circuit and The vehicle drive device according to claim 1, wherein each of the cooling units is located on the second electric motor side of the second switching circuit. 3. Each of the first and second switching circuits includes a switching element and a heat radiating portion that radiates heat generated by the operation of the switching element to the outside, and each of the heat radiating portions includes the respective heat radiating portions. The vehicle drive device according to claim 2, wherein the first and second switching circuits are arranged so as to be in contact with the cooling part of the vehicle. 4. A first switching element control circuit that controls the operation of a switching element that constitutes the first switching circuit, and a second switching element control circuit that controls the operation of a switching element that constitutes the second switching circuit. The first switching element control circuit and the second switching element control circuit are formed on a single printed circuit board arranged between the first and second switching circuits. Alternatively, the vehicle drive device according to item 3. 5. The first switching element control circuit,
The vehicle drive according to claim 4, wherein the second switching element control circuit is formed on the surface of the printed board on the first switching circuit side, and the second switching element control circuit is formed on the surface of the printed board on the second switching circuit side. apparatus. 6. The vehicle drive device according to claim 1, wherein each of the cooling units is formed of opposing walls of housings of the first and second electric motors that face each other. 7. The housing further comprises a housing having the first and second switching circuits housed therein and having an outer wall surface and an inner wall surface, wherein each of the heat radiating portions is provided on a pair of inner wall surfaces of the housing facing each other. The first and second switching circuits are arranged so as to be in contact with each other, and the outer wall surface corresponding to the pair of inner wall surfaces is in contact with the mutually facing wall surfaces of the first and second electric motors, respectively. The vehicle drive device according to any one of claims 1 to 6, wherein a body is arranged. 8. The vehicle drive device according to claim 7, wherein each of the cooling units is formed of a wall of the housing. 9. The first and second electric motors are arranged so as to be interposed between first and second electric motors coaxially arranged.
A power conversion unit comprising: first and second switching circuits that drive each of the electric motors; and a housing that houses the first and second switching circuits therein. Each of them includes a switching element and a heat radiating portion that radiates heat generated by the operation of the switching element to the outside, and each of the heat radiating portions is provided on the inner wall surface of the housing on the first electric motor side. A power conversion unit in which the first and second switching circuits are arranged so as to contact the inner wall surface located and the inner wall surface located on the second electric motor side, respectively. 10. A first switching element control circuit that controls the operation of a switching element that constitutes the first switching circuit, and a second switching element control circuit that controls the operation of a switching element that constitutes the second switching circuit. 10. The first switching element control circuit and the second switching element control circuit are formed on a single printed circuit board arranged between the first and second switching circuits. Power conversion unit described in. 11. The first switching element control circuit is formed on a surface of the printed board on the first switching circuit side, and the second switching element control circuit is formed.
The power conversion unit according to claim 10, wherein the power conversion unit is formed on a surface of the printed circuit board on the second switching circuit side. 12. The power conversion unit according to claim 9, wherein each of the cooling units is formed by a wall of the housing. 13. The power according to claim 9, further comprising a smoothing capacitor for smoothing the power supplied to the first and second switching circuits, which is further housed in the housing. Conversion unit.