JP7140727B2 - Mechanical and electrical integrated vehicle drive system - Google Patents

Description

The present invention provides an electric motor having a motor cooling portion provided in a casing, and a transaxle having an output shaft parallel to the rotation axis of the electric motor and outputting rotational power transmitted from the electric motor from the output shaft. and a power control unit that controls the operation of the electric motor, and a circuit cooling device that cools the power control unit.

A mechanical-electrical integrated vehicle drive system in which a power drive unit that supplies drive power to the electric motor is arranged above the electric motor and a cooling device that cools the electric motor and the power drive unit is housed in a casing is disclosed in Patent Document 1. Are known.

JP 2019-80432 A

In the device disclosed in Patent Document 1, the power drive unit is arranged above the electric motor, so that the total height of the electromechanical integrated vehicle drive device is increased. It is desired to improve it because the space between and becomes narrower and the crushable zone becomes smaller.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electromechanically integrated vehicle drive system capable of reducing the overall height.

In order to achieve the above object, the present invention provides an electric motor having a motor cooling portion provided in a casing, and a rotary power transmitted from the electric motor having an output shaft parallel to the rotation axis of the electric motor. A mechanical and electrical integrated vehicle drive system comprising a transaxle output from the output shaft, a power control unit controlling the operation of the electric motor, and a circuit cooling device cooling the power control unit, wherein the cooling liquid is supplied to the circuit. a liquid cooling system circulating in a cooling device; an oil cooling system circulating oil in a transaxle cooling portion provided in the transaxle and the motor cooling portion; and extending above a drive shaft connected to the output shaft. a support shelf integrally connected to the casing and on which the power control unit and the circuit cooling device are mounted; a stiffening portion integrally connecting the attachment portion of the casing and the bottom surface of the support shelf and extending linearly; A first feature is that it includes a coolant passage that constitutes a part of the flow passage.

Further, in addition to the configuration of the first characteristic, the present invention has a configuration in which a part of the transaxle is arranged behind the casing in the longitudinal direction of the vehicle, and the mounting portion is arranged in the transaxle in the longitudinal direction of the vehicle. A second aspect is that the oil cooler provided on the side wall of the casing facing the rear portion of the casing and attached to the mounting portion is disposed below an imaginary horizontal plane including the axis of the output shaft. Characterized by

Further, in the present invention, in addition to the configuration of the second characteristic, the drive shaft is connected to the output shaft so as to be swingable while the vehicle is running, and the support shelf, the stiffening portion and the oil cooler are A third feature is that the drive shaft is arranged outside the planned swinging range of the drive shaft.

According to the first feature of the present invention, the power control unit and the circuit cooling device are mounted on the support shelf integrally connected to the casing and extending above the drive shaft connected to the output shaft. Since there is no power control unit above the electric motor, the total height of the electromechanical integrated vehicle drive system can be reduced. Moreover, by arranging the power control unit at a position separated from the casing, heat transfer from the electric motor to the power control unit is suppressed, and cooling of the power control unit by the circuit cooling device is facilitated, achieving a sufficient cooling effect. be able to. Further, since the stiffening portion is provided between the support shelf and the casing, the support shelf can be supported by the casing with high rigidity, and the vibration resistance of the power control unit can be enhanced. Furthermore, since the cooling fluid passage that constitutes a part of the liquid cooling system is formed in the linear stiffening portion, the cooling fluid passage extends linearly to suppress the pressure loss in the cooling fluid passage. It is possible to reduce the head required for the cooling liquid pump for circulating the cooling liquid and contribute to the downsizing of the cooling liquid pump, and the cooling liquid pipe that constitutes a part of the liquid cooling system can be installed later. As compared with the case, the assembly work of the driving device becomes easier.

According to the second feature of the present invention, the mounting portion to which the oil cooler is mounted is provided on the side wall of the casing facing the portion of the transaxle disposed behind the casing. The cooling liquid pipe that constitutes a part of the system does not protrude to the periphery of the electromechanical integrated vehicle drive system, which contributes to making the whole system compact. Moreover, the oil cooler is arranged between the casing and a part of the transaxle in the longitudinal direction of the vehicle, so that the oil cooler can be protected from direct hits such as flying stones and sludge and external impacts. In addition, since the oil cooler is arranged below the virtual horizontal plane including the axis of the output shaft, maintenance of the oil cooler is facilitated by preventing the output shaft and the drive shaft from interfering with work. can be

Furthermore, according to the third feature of the present invention, even if the drive shaft swings while the vehicle is running, it does not interfere with the support shelf, the stiffening portion and the oil cooler.

FIG. 4 is a partially cutaway front view showing the electromechanical integrated vehicle drive device cut along line 1-1 of FIG. 3; FIG. 2 is a view in the direction of arrow 2 of FIG. 1; It is a 3 arrow directional view of FIG. It is a system diagram of a cooling system.

An embodiment of the present invention will be described with reference to the attached FIGS. and includes a motor generator 11 that is an electric motor, and a transaxle 12 that outputs rotational power transmitted from the motor generator 11 in a decelerated state.

The transaxle 12 comprises a transaxle case 21 containing a speed reducer 20 (see FIG. 4) that reduces the rotational speed of the rotational power transmitted from the motor generator 11 and transmits it to the pair of output shafts 19 . The pair of output shafts 19 are arranged coaxially with the final gear 20a (see FIG. 4) of the speed reducer 20 and parallel to the axis of the rotation shaft 18 of the motor generator 11, that is, the rotation axis. be. The final gear 20a and the pair of output shafts 19 constitute a well-known differential gear mechanism (differential gear; not shown) for distributing the rotational power to a pair of left and right drive wheels of an electric vehicle.

The transaxle case 21 of the transaxle 12 includes an inner half body 21a connected to the casing 13 of the motor generator 11 on one end side of the rotating shaft 18, and an inner half body 21a connected to the casing 13 of the motor generator 11 on one end side of the rotating shaft 18. and an outer half 21b covering the open end of 21a.

One output shaft 19 of the pair of output shafts 19 is rotatably supported by the transaxle case 21 while exposing a part of the output shaft 19 to the outside from the projecting end of the projecting portion 21aa, and the other output shaft 19 is supported. 19 is coaxial with one of the output shafts 19 and is rotatably supported by the transaxle case 21 while exposing a portion of the outer half body 21b to the outside.

A drive shaft 22 is connected to the output shaft 19 via a universal joint 23, so that the drive shaft 22 can swing in any direction up, down, forward, or backward within the range of angle α when the vehicle is running. be.

By the way, the operation of the motor generator 11 is controlled by the power control unit 25 . This power control unit 25 includes a power module 26 , an ECU 27 and a capacitor module 28 and is cooled by a circuit cooling device 29 . On the other hand, the casing 13 of the motor generator 11 is integrally provided with a support shelf 30 that extends upward from the drive shaft 22 of the pair of drive shafts 22 arranged on the side of the casing 13, The power control unit 25 and the circuit cooling device 29 are mounted on the support shelf 30 .

The support shelf 30 integrally has a box-shaped accommodation portion 30a that opens upward, and the power control unit 25 and the circuit cooling device 29 are arranged on the support shelf 30. The power control unit 25 placed on the device 29 is accommodated in the accommodating portion 30a, and a lid member 31 is attached to the upper end of the accommodating portion 30a to close the upper end opening of the accommodating portion 30a.

A mounting portion 34 is provided on a portion of the transaxle 12 disposed behind the casing 13 in the longitudinal direction of the vehicle, i. is provided, and an oil cooler 35 arranged below a virtual horizontal plane IH (see FIG. 1) including the axis of the output shaft 19 is attached to the attachment portion 34 .

Moreover, the attachment portion 34 of the casing 13 and the bottom surface of the support shelf 30 are integrally connected by a pair of rib-like stiffening portions 32 and 33 extending linearly. Moreover, the support shelf 30 , the stiffening portions 32 and 33 and the oil cooler 35 are arranged outside the planned swinging range of the drive shaft 22 connected to the output shaft 19 .

In FIG. 4, a liquid cooling system 38 for circulating a cooling liquid such as an antifreeze liquid to the circuit cooling device 29 circulates the cooling liquid to the radiator 40, the circuit cooling device 29 and the oil cooler 35 by a cooling liquid pump 41. The suction side of the coolant pump 41 is connected to the radiator 40 via a suction pipe 42, and the discharge side of the coolant pump 41 is located in the support shelf 30 on which the circuit cooling device 29 is mounted. The coolant discharged from the circuit cooling device 29 is led to the oil cooler 35 through a first cooling liquid passage 44 and is connected to an introduction side connection pipe 43 provided in the portion 30a and leading to the circuit cooling device 29. , the coolant that has exchanged heat with the oil in the oil cooler 35 is guided through a second coolant passage 45 to a lead-out side connection pipe 46 provided in the housing portion 30a of the support shelf 30. The lead-out side connection pipe 46 is connected to the radiator 40 .

The first cooling liquid passage 44 and the second cooling liquid passage 45 constitute a part of the flow passage of the liquid cooling system 38, and are connected to the mounting portion 34 of the casing 13 and the support shelf. A first coolant passage 44 is formed in one stiffening portion 32 of the pair of stiffening portions 32 and 33 integrally connecting the bottom surface of the cooling device 30, and a first coolant passage 44 is formed in the other stiffening portion 33. Two coolant passages 45 are formed.

A motor cooling portion 48 is provided in the casing 13 of the motor generator 11, and a transaxle cooling portion 49 is provided in the transaxle case 21 of the transaxle 12. The motor cooling portion 48 and the The transaxle cooling part 49 achieves lubrication and cooling of moving parts by spraying oil. It has a spray bar 50 located on top.

An oil cooling system 51 that circulates oil to the motor cooling portion 48 and the transaxle cooling portion 49 includes oil sprayed from the spray bar 50 and accumulated in the lower portion of the casing 13 and the transaxle case 21 . The oil sent from the oil pump 52 accommodated in the transaxle case 21 performs heat exchange with the cooling liquid of the liquid cooling system 38 in the oil cooler 35, and furthermore, the It is sent to the spray bar 50.

Next, the operation of this embodiment will be described. A support shelf 30 extending above the drive shaft 22 connected to the output shaft 19 of the transaxle 12 is integrally connected to the casing 13 of the motor generator 11 . Since the power control unit 25 for controlling the operation of the motor generator 11 and the circuit cooling device 29 for cooling the power control unit 25 are mounted on the support shelf 30, the power control unit is mounted above the motor generator 11. 25, the overall height of the electromechanical integrated vehicle drive system can be reduced. Moreover, since the power control unit 25 is arranged at a position separated from the casing 13, the heat transfer from the motor generator 11 to the power control unit 25 is suppressed, and the cooling of the power control unit 25 by the circuit cooling device 29 is prevented. It becomes easy and sufficient cooling effect can be obtained.

Further, since the mounting portion 34 provided on the casing 13 and the bottom surface of the support shelf 30 are integrally connected by the stiffening portions 32 and 33 extending linearly, the support shelf 30 can be supported by the casing 13 with high rigidity. , and the vibration resistance of the power control unit 25 can be improved.

In addition, oil is supplied to a liquid cooling system 38 that circulates the cooling liquid to the circuit cooling device 29, a motor cooling section 48 provided in the casing 13 of the motor generator 11, and a transaxle cooling section 49 provided in the transaxle 12. An oil cooler 35 that exchanges heat with the circulating oil cooling system 51 is attached to a mounting portion 34 provided in the casing 13, and constitutes a part of the circulation path of the liquid cooling system 38. Since the two coolant passages 44, 45 are formed in the stiffening portions 32, 33, the coolant passages 44, 45 extend linearly from the first and second coolant passages 44, 45. 45, the pressure loss at 45 can be kept low, and the head required for the cooling liquid pump 41 for circulating the cooling liquid in the liquid cooling system 38 can be suppressed, thereby contributing to downsizing of the cooling liquid pump 41 and liquid cooling. This facilitates assembly of the driving device compared to the case where the cooling liquid line forming part of the system 38 is retrofitted.

A part of the transaxle 12 is arranged behind the casing 13 in the vehicle front-rear direction, and the attachment portion 34 to which the oil cooler 35 is attached is located behind the casing 13 in the vehicle front-rear direction of the transaxle 12 . Since it is provided on the side wall of the casing 13 so as to face the portion where the oil cooler 35 is arranged, the oil cooler 35 and the coolant pipe line forming part of the liquid cooling system 38 protrude to the periphery of the electromechanical integrated vehicle drive system. In addition, the oil cooler 35 is arranged between a part of the casing 13 and the transaxle 12 in the longitudinal direction of the vehicle, so that the oil cooler 35 is free from flying stones and sludge. It is possible to protect against direct hits and external impacts.

In addition, since the oil cooler 35 is arranged below the imaginary horizontal plane IH including the axis of the output shaft 19, the oil cooler 35 can be inspected by simply lifting up the vehicle while the drive device remains in the vehicle during maintenance work. can do. That is, the output shaft 19 and the drive shaft 22 do not interfere with the work, and maintenance can be facilitated.

Further, the drive shaft 22 is connected to the output shaft 19 so as to be able to swing while the vehicle is running. Since it is arranged outside the planned range, even if the drive shaft 22 swings while the vehicle is running, it does not interfere with the support shelf 30, the stiffening portions 32 and 33, and the oil cooler 35.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes may be made without departing from the scope of the present invention described in the claims. is possible.

Reference Signs List 11 Motor generator which is an electric motor 12 Transaxle 13 Casing 19 Output shaft 22 Drive shaft 25 Power control unit 29 Circuit cooling device 30 Support shelves 32, 33 stiffening portion 35 oil cooler 38 liquid cooling system 44, 45 coolant passage 48 motor cooling portion 49 transaxle cooling portion 51 ... Oil cooling system IH ... Virtual horizontal plane

Claims (3)

An electric motor (11) provided with a motor cooling part (48) in a casing (13), and an output shaft (19) parallel to the rotation axis of the electric motor (11). a transaxle (12) for outputting the transmitted rotational power from the output shaft (19); a power control unit (25) for controlling the operation of the electric motor (11); and cooling the power control unit (25). a liquid cooling system (38) for circulating cooling liquid to the circuit cooling device (29); and a liquid cooling system (38) provided in the transaxle (12). An oil cooling system (51) for circulating oil in a transaxle cooling section (49) and the motor cooling section (48), and an oil cooling system (51) extending above a drive shaft (22) connected to the output shaft (19). A support shelf (30) integrally connected to the casing (13) and on which the power control unit (25) and the circuit cooling device (29) are mounted; 34) to perform heat exchange between the liquid cooling system (38) and the oil cooling system (51); the mounting portion (34) of the casing (13); stiffening portions (32, 33) extending linearly by integrally connecting the bottom surfaces of (30); and cooling liquid passages (44, 45) forming part of the electromechanical integrated vehicle drive system. A part of the transaxle (12) is arranged behind the casing (13) in the longitudinal direction of the vehicle, and the mounting portion (34) is located in the casing (13) in the longitudinal direction of the vehicle. ) on the side wall of the casing (13) and attached to the mounting portion (34), the oil cooler (35) is positioned on a virtual horizontal plane including the axis of the output shaft (19). 2. The electromechanical integrated vehicle drive system according to claim 1, wherein the drive system is arranged below (IH). The drive shaft (22) is connected to the output shaft (19) so as to be able to swing while the vehicle is running, and includes the support shelf (30), the stiffening portions (32, 33) and the oil cooler (35). 3. The electromechanically integrated vehicle drive system according to claim 2, wherein the drive shaft (22) is arranged outside the expected swinging range of the drive shaft (22).

Images