JP2020063010A - Driving device of vehicle - Google Patents

Abstract

To provide a driving device of a vehicle that can suppress increase in weight due to insulation materials for insulating an electricity supply system while driving motors with comparatively high voltages.SOLUTION: A driving device (10) of a vehicle, which drives wheels using motors, comprises: motors (20 and 21) for rear wheels, arranged between rear wheels (2a), which drive the rear wheels; a battery (18) accumulating electric energy for driving the motors for rear wheels; capacitors (22 and 23) accumulating electric energy for driving the motors for rear wheels; and wire harnesses (22a and 23a) that supply electricity from the capacitors to the motors for rear wheels. The motors for rear wheels are supplied with electricity from the battery and the capacitors connected in series, and the capacitors are arranged between the left and right rear wheels of the vehicle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle drive device, and more particularly to a vehicle drive device that drives wheels using an internal combustion engine and a motor.

  In recent years, regulations on vehicle exhaust gas have been tightened in various countries around the world, and demands for vehicle fuel efficiency, carbon dioxide emission per mileage, etc. have become strict. In addition, there are some cities that regulate the entry of vehicles running on internal combustion engines into urban areas. In order to satisfy these requirements, hybrid drive vehicles equipped with an internal combustion engine and a motor, and electric vehicles driven only by the motor have been developed and widely spread.

  On the other hand, Japanese Patent Laying-Open No. 2016-107734 (Patent Document 1) describes a vehicle power supply control device. This power supply control device includes a gear drive starter, an ISG (Integrated Starter Generator), a capacitor, a DC-DC converter, and a lead storage battery. In this power supply control device, the capacitor and the lead storage battery are connected in parallel via a DC-DC converter. Further, the electric power generated by the ISG is once charged in the capacitor and then stepped down by the DC-DC converter to be charged in the lead storage battery. The electric power stored in the lead storage battery is used to drive electric components such as a gear-driven starter.

JP, 2016-107734, A

  Driving a vehicle with a motor does not emit carbon dioxide while driving, so it is advantageous for clearing emission regulations that are tightened year by year, but there is a limit to the amount of electrical energy that can be stored in the battery, and it is long enough. It is difficult to secure cruising range. For this reason, as a vehicle drive device, a hybrid drive device in which an internal combustion engine is mounted together with a motor is widely used. Further, also in such a hybrid drive device, in order to reduce the carbon dioxide emission amount during traveling, it is necessary to mainly use the driving force of the motor.

  As described above, in the vehicle drive device mainly composed of the driving force of the motor, it is necessary to obtain sufficient driving force by the motor in order to secure sufficient traveling performance. In order to obtain a sufficient driving force from the motor, it is necessary to operate the motor at a high voltage. That is, when the motor is driven at a low voltage, the current required for driving becomes excessive and it is required to make the impedance of the power transmission system extremely small. However, when operating a motor at a high voltage, it is necessary to electrically insulate the electrical system that supplies the motor with a high voltage, and this insulating material increases the overall weight of the vehicle and There is a problem of deteriorating fuel efficiency.

  Therefore, an object of the present invention is to provide a vehicle drive device capable of suppressing an increase in weight due to an insulating material that insulates a power supply system while driving a motor at a relatively high voltage.

  In order to solve the above-described problems, the present invention is a vehicle drive device that drives a wheel using a motor, and a rear wheel motor that is disposed between the rear wheels of the vehicle and drives the rear wheel. , A battery storing electric energy for driving the rear wheel motor, a capacitor storing electric energy for driving the rear wheel motor, and a wire harness for supplying electric power from the capacitor to the rear wheel motor The electric power is supplied to the rear wheel motor from a battery and a capacitor connected in series, and the capacitor is arranged between the left and right rear wheels of the vehicle.

  In the present invention thus configured, the rear wheel motor arranged between the rear wheels of the vehicle drives the rear wheels. The battery and the capacitor store electric energy for driving the rear wheel motor, and electric power is supplied to the rear wheel motor from the battery and the capacitor connected in series. The capacitor is arranged between the left and right rear wheels of the vehicle, and the electric power from the capacitor is supplied to the rear wheel motor by the wire harness.

  According to the present invention thus configured, electric power is supplied to the rear wheel motor from the battery and the capacitor connected in series, so that the rear wheel motor is driven at a higher voltage than in the case where only the battery is driven. Therefore, the drive current can be suppressed low. Further, since a relatively high voltage is applied to the wire harness that supplies the electric power from the capacitor to the rear wheel motor, it is necessary to increase the withstand voltage. However, since the electric power is supplied to the rear wheel motor from the capacitor arranged between the left and right rear wheels of the vehicle, the wire harness for supplying the electric power can be shortened. As a result, even if the withstand voltage of the wire harness is increased, the increase in weight is reduced and the increase in weight due to the insulating material can be suppressed.

In the present invention, preferably, the capacitor is arranged at a position where at least a part thereof overlaps with the rear wheel when viewed from the side of the vehicle.
According to the present invention thus configured, since the capacitor is arranged at a position where at least a part of the capacitor overlaps with the rear wheel when viewed from the side of the vehicle, the wire harness for supplying electric power to the rear wheel motor. Can be further shortened, and an increase in weight due to the insulating material can be further suppressed.

In the present invention, the rear wheel motor is preferably an in-wheel motor provided on each of the left and right rear wheels of the vehicle.
According to the present invention thus configured, since the rear wheel motor is an in-wheel motor, the rear wheel is directly driven without the need for a power transmission mechanism for transmitting the driving force of the rear wheel motor to the rear wheel. Therefore, the weight of the vehicle can be reduced.

  In the present invention, preferably, further, there is a rear differential gear arranged between the left and right rear wheels and transmitting power to the left and right rear wheels, and the capacitor is arranged between the rear differential gear and the rear wheels. ing.

  According to the present invention thus configured, even in a vehicle in which the left and right rear wheels are driven via the rear differential gear, the capacitor can be arranged in the vicinity of the rear wheels, and the electric power is supplied to the rear wheel motor. The wire harness to be supplied can be shortened. This can suppress an increase in weight of the wire harness due to the insulating material.

  In the present invention, preferably, the capacitor is further provided between the left and right rear wheels and on the front side of the rear differential gear, and has a coupling for transmitting the input driving force to the rear differential gear, and the capacitor is a cup. It is arranged between the ring and the rear wheel.

  According to the present invention having such a configuration, even in a vehicle in which the left and right rear wheels are driven through the coupling, the capacitor can be arranged in the vicinity of the rear wheels, and power is supplied to the rear wheel motor. The wire harness to be used can be shortened. This can suppress an increase in weight of the wire harness due to the insulating material.

In the present invention, preferably, the battery is arranged in the tunnel portion provided in the lower portion of the vehicle or in the rear portion of the vehicle so as to extend in the front-rear direction of the vehicle.
According to the present invention thus configured, since the battery is arranged in the tunnel portion or in the rear portion of the vehicle, a sufficient space for accommodating the battery can be secured. Also, by arranging the battery in this way, the wiring that connects the battery and the capacitor in series may be relatively long, but since the wiring has a relatively low voltage, the increase in weight due to the insulating material is suppressed. can do.

In the present invention, the maximum terminal voltage of the capacitor is preferably higher than the terminal voltage of the battery.
According to the present invention thus configured, the maximum inter-terminal voltage of the capacitor is configured to be higher than the inter-terminal voltage of the battery. Therefore, by connecting the capacitors in series, the inter-terminal voltage of the battery is reduced. It can be greatly raised. As a result, the rear wheel motor can be driven at a high voltage while using the battery of a relatively low voltage.

  According to the vehicle drive device of the present invention, it is possible to suppress an increase in weight due to the insulating material that insulates the power supply system while driving the motor at a relatively high voltage.

1 is a layout diagram of a vehicle equipped with a vehicle drive device according to a first embodiment of the present invention. 1 is a block diagram showing a power supply configuration of a vehicle drive device according to a first embodiment of the present invention. FIG. 6 is a diagram schematically showing an example of a change in voltage when electric power is regenerated in the capacitor in the vehicle drive device according to the first embodiment of the present invention. FIG. 3 is a diagram showing the relationship between the output of each motor and the vehicle speed used in the vehicle drive device according to the first embodiment of the present invention. FIG. 3 is a sectional view schematically showing the structure of an auxiliary drive motor used in the vehicle drive device according to the first embodiment of the present invention. FIG. 1 is a perspective view showing a suspension structure of rear wheels in a vehicle to which a vehicle drive device according to a first embodiment of the present invention is applied. FIG. 3 is a perspective view of a rear wheel portion of a vehicle to which the vehicle drive device according to the first embodiment of the present invention is applied, as viewed from the side. FIG. 8 is a layout diagram of a vehicle equipped with a vehicle drive device according to a second embodiment of the present invention. FIG. 11 is a perspective view showing a suspension structure of rear wheels in a vehicle to which a vehicle drive device according to a second embodiment of the present invention is applied. FIG. 11 is a perspective view of a rear wheel portion of a vehicle to which the vehicle drive device according to the second embodiment of the present invention is applied, as seen from the side.

Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a layout diagram of a vehicle equipped with a vehicle drive device according to a first embodiment of the present invention.

  As shown in FIG. 1, a vehicle 1 equipped with a vehicle drive device according to a first embodiment of the present invention has an engine 12, which is an internal combustion engine, mounted in front of the driver's seat and is a main drive wheel. It is a so-called FF (Front engine, Front drive) vehicle that drives a pair of left and right front wheels 2b. Further, as will be described later, the front wheels 2b are also driven by the main drive motor 16, and the pair of left and right rear wheels 2a which are the sub drive wheels are driven by the sub drive motor.

  A vehicle drive device 10 according to the first embodiment of the present invention mounted on a vehicle 1 includes an engine 12 that drives front wheels 2b, a transmission 14 that is a transmission, a main drive motor 16 that drives the front wheels 2b, and a battery 18. And a control device 24 which is a controller. Further, the vehicle drive device 10 is an auxiliary drive motor 20 that is an in-wheel motor that drives the right rear wheel 2a, a capacitor 22 that is arranged in the vicinity thereof, and an in-wheel motor that drives the left rear wheel 2a. It has a sub drive motor 21 and a capacitor 23 arranged in the vicinity thereof.

  The engine 12 is an internal combustion engine for generating driving force for the front wheels 2b that are the main driving wheels of the vehicle 1. In this embodiment, an in-line four-cylinder engine is adopted as the engine 12, and the engine 12 arranged in the front part of the vehicle 1 drives the front wheels 2b via the transmission 14 and a differential gear (not shown). It has become. Further, in the present embodiment, the engine 12 is in a so-called “horizontal installation” in which four cylinders arranged in series are arranged in the left-right direction of the vehicle 1. Exhaust gas of the engine 12 is discharged from the rear end of the vehicle 1 through an exhaust pipe (not shown). This exhaust pipe is formed in the center of the lower part of the vehicle so as to extend in the front-rear direction. It is threaded through section 15.

  The transmission 14 is a multi-stage transmission that converts the rotational speed of the output shaft of the engine 12 and outputs the converted rotational speed. The output of the transmission 14 is transmitted to each of the front wheels 2b via a differential gear (not shown).

  The main drive motor 16 is an electric motor for generating a driving force for the main drive wheels, is provided on the vehicle body of the vehicle 1, and is arranged laterally of the engine 12 adjacent to the engine 12. Functions as a side motor. An inverter 16a is arranged in the front part of the vehicle 1, and the inverter 16a converts the DC voltage of the battery 18 into an AC voltage and supplies the AC voltage to the main drive motor 16. Further, as shown in FIG. 1, the main drive motor 16 is connected in series with the engine 12, and the driving force generated by the main drive motor 16 is also transmitted to the front wheels 2 b via the transmission 14. Further, in the present embodiment, as the main drive motor 16, a 25 kW permanent magnet electric motor (permanent magnet synchronous electric motor) driven by 48 V is adopted.

  The battery 18 is a power storage device mainly for storing electric energy for operating the main drive motor 16. Further, in the present embodiment, as the battery 18, a 48V, 3.5 kWh lithium ion battery (LIB) is used. Further, as shown in FIG. 1, in the present embodiment, the battery 18 is arranged in the tunnel portion 15 provided in the lower portion of the vehicle. Alternatively, as a modified example, the battery 18 may be arranged in the rear portion of the vehicle 1 as shown by an imaginary line in FIG.

  Next, the auxiliary drive motors 20 and 21 are respectively provided on the rear wheels 2a so as to generate a driving force for the rear wheels 2a which are the auxiliary drive wheels. The auxiliary drive motors 20 and 21 are in-wheel motors, and are housed in the respective wheels of the rear wheel 2a. Therefore, the auxiliary drive motors 20 and 21 are arranged between the left and right rear wheels 2a of the vehicle 1 and are provided in the so-called "under spring" of the vehicle 1. Further, as shown in FIG. 1, the current from the capacitor (CAP) 22 is converted into an alternating current by the inverter 20a and supplied to the right side sub-driving motor 20, respectively. Similarly, the current from the capacitor 23 is converted into alternating current by the inverter 21a and supplied to the left sub-driving motor 21 respectively. Further, in the present embodiment, the sub drive motors 20 and 21 are not provided with a speed reducer, which is a speed reduction mechanism, and the driving force of the sub drive motors is directly transmitted to the rear wheels 2a to directly drive the wheels. It In addition, in the present embodiment, an induction motor of 17 kW is adopted as each of the auxiliary drive motors 20 and 21.

  The capacitor 22 on the right side is provided so as to store the electric power regenerated by the sub drive motor 20, and the capacitor 23 on the left side is provided so as to store the electric power regenerated by the sub drive motor 21. As shown in FIG. 1, the capacitor 22 is arranged in the vicinity of the auxiliary drive motor 20 provided on the right rear wheel 2a of the vehicle 1, and the capacitor 23 is provided on the left rear wheel 2a of the vehicle 1. It is located near. Electric power from the capacitor 22 is supplied to the auxiliary drive motor 20 provided on the right rear wheel 2a of the vehicle 1 via the wire harness 22a, and electric power from the capacitor 23 is provided on the left rear wheel 2a. The auxiliary drive motor 21 is supplied to each of the auxiliary drive motors 21 via a wire harness 23a.

  Further, each of the capacitors 22 and 23 is configured to store electric charges at a voltage higher than that of the battery 18, and is arranged in a region between the left and right rear wheels 2a which are auxiliary driving wheels. That is, the capacitors 22 and 23 are arranged at a position where at least a part of the capacitors 22 and 23 overlaps with the rear wheel 2a when viewed from the side of the vehicle. The sub-driving motors 20 and 21 driven mainly by the electric power stored in the capacitor are driven at a voltage higher than the terminal voltage of the battery 18.

  As shown in FIG. 1, the control device 24 is configured to control the engine 12, the main drive motor 16, and the auxiliary drive motors 20 and 21 to execute the electric motor traveling mode and the internal combustion engine traveling mode. Specifically, the control device 24 can be configured by a microprocessor, a memory, an interface circuit, a program for operating these (above, not shown), and the like.

Next, with reference to FIG. 2 to FIG. 5, the power supply configuration of the vehicle drive device 10 according to the first embodiment of the present invention and the drive of the vehicle 1 by the motor will be described.
FIG. 2 is a block diagram showing the power supply configuration of the vehicle drive device 10 according to the first embodiment of the present invention. FIG. 3 is a diagram schematically showing an example of a change in voltage when electric power is regenerated in the capacitor in the vehicle drive device 10 of the present embodiment. FIG. 4 is a diagram showing the relationship between the output of each motor used in the vehicle drive device 10 of the present embodiment and the vehicle speed.

  As shown in FIG. 2, the battery 18 and the capacitor 22 and the battery 18 and the capacitor 23 provided in the vehicle drive device 10 are connected in series, respectively. The electric power of the battery 18 is supplied to the main drive motor 16. Further, the auxiliary drive motor 20 is supplied with electric power from the battery 18 and the capacitor 22 connected in series, and the auxiliary drive motor 21 is supplied with electric power from the battery 18 and the capacitor 23 connected in series. That is, the main drive motor 16 is driven by the reference output voltage of the battery 18, which is about 48V, and the sub drive motors 20 and 21 are the sum of the voltage of the battery 18 and the voltage between the terminals of the capacitors, which is a maximum of 120V higher than 48V. It is driven by the voltage of. Thus, the maximum terminal voltage of the capacitors 22 and 23 is set higher than the terminal voltage of the battery 18.

  By connecting in this way, the auxiliary drive motors 20 and 21 which are rear wheel motors are driven by the electric energy stored in the battery and the capacitor. The capacitor 22 stores electric energy supplied to the sub drive motor 20, and the sub drive motor 20 is always driven by the electric power supplied via the capacitor 22. Similarly, electric energy supplied to the sub drive motor 21 is accumulated in the capacitor 23, and the sub drive motor 21 is always driven by the electric power supplied via the capacitor 23.

  Further, an inverter 16a is attached to the main drive motor 16, and the main drive motor 16 which is a permanent magnet electric motor is driven after converting the output of the battery 18 into an alternating current. On the other hand, the output of the capacitor 22 (the voltage obtained by connecting the battery 18 and the capacitor 22 in series) is input to the inverter 20a, and the inverter 20a converts the input DC voltage into AC and then requests the auxiliary drive motor 20. Electric power is output and the sub drive motor 20 is driven. Similarly, the output of the capacitor 23 is input to the inverter 21a, and the inverter 21a converts the input DC voltage into AC and outputs the electric power required by the auxiliary drive motor 21.

  Further, during deceleration of the vehicle 1 and the like, the main drive motor 16 and the sub-drive motors 20 and 21 function as a generator to regenerate the kinetic energy of the vehicle 1 to generate electric power. The electric power regenerated by the main drive motor 16 is stored in the battery 18, and the electric power regenerated by the sub drive motors 20 and 21 is mainly stored in the capacitors 22 and 23, respectively.

  A high-voltage DC / DC converter 26a, which is a voltage converter, is connected between the battery 18 and the capacitors 22 and 23. The high-voltage DC / DC converter 26a lacks the charge accumulated in the capacitor 22 or 23. When (the voltage between the terminals of the capacitor has dropped), the voltage of the battery 18 is boosted and the capacitor 22 or 23 is charged. On the other hand, when the voltage between the terminals of the capacitor 22 or 23 rises above a predetermined voltage due to the regeneration of energy by the auxiliary drive motor 20 or 21, the charge accumulated in the capacitor is stepped down and applied to the battery 18, 18 is charged. That is, after the electric power regenerated by the auxiliary drive motors 20 and 21 is accumulated in the capacitors 22 and 23, respectively, a part of the accumulated electric charges is charged in the battery 18 via the high-voltage DC / DC converter 26a.

  Further, a low-voltage DC / DC converter 26b is connected between the battery 18 and the 12V electric component 25 of the vehicle 1. Since the control device 24 of the vehicle drive device 10 and most of the electrical components 25 of the vehicle 1 operate at a voltage of 12V, the electric charge accumulated in the battery 18 is stepped down to 12V by the low-voltage DC / DC converter 26b, and these electric charges are reduced. Supply to equipment.

Next, charging and discharging of the capacitor will be described with reference to FIG. Although the charging / discharging of the capacitor 22 will be described here, the charging / discharging of the capacitor 23 is performed in the same manner.
As shown in FIG. 3, the voltage of the capacitor 22 is the sum of the base voltage of the battery 18 and the terminal voltage of the capacitor 22 itself. When the vehicle 1 is decelerated or the like, the auxiliary drive motor 20 regenerates electric power, and the regenerated electric power is charged in the capacitor 22. When the capacitor 22 is charged, the terminal voltage rises relatively rapidly. When the voltage of the capacitor 22 rises above a predetermined voltage due to charging, the voltage of the capacitor 22 is stepped down by the high voltage DC / DC converter 26a, and the battery 18 is charged. As shown in FIG. 3, the charging of the battery 18 from the capacitor 22 is performed more gently than the charging of the capacitor 22, and the voltage of the capacitor 22 is reduced to an appropriate voltage relatively slowly.

That is, the electric power regenerated by the auxiliary drive motor 20 is temporarily stored in the capacitor 22, and then the battery 18 is gently charged. Depending on the period in which the regeneration is performed, the regeneration of the electric power by the auxiliary drive motor 20 and the charging of the battery 18 from the capacitor 22 may be performed in an overlapping manner.
On the other hand, the electric power regenerated by the main drive motor 16 directly charges the battery 18.

  Next, the relationship between the vehicle speed and the output of each motor in the vehicle drive device 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 4 is a graph showing the relationship between the speed of the vehicle 1 and the output of each motor at each speed in the vehicle drive device 10 of the present embodiment. In FIG. 4, the output of the main drive motor 16 is indicated by a broken line, the output of one auxiliary drive motor is indicated by a dashed line, the total output of the two auxiliary drive motors 20 and 21 is indicated by a dashed line, and the outputs of all motors are indicated. Is indicated by a solid line. Note that FIG. 4 shows the speed of the vehicle 1 on the horizontal axis and the output of each motor on the vertical axis, but since the speed of the vehicle 1 and the rotational speed of the motor have a fixed relationship, the horizontal axis is shown. Even when the number of motor revolutions is set, the output of each motor draws a curve similar to that in FIG.

  In this embodiment, since a permanent magnet electric motor is adopted as the main drive motor 16, as shown by the broken line in FIG. 4, the output of the main drive motor 16 is large in the low vehicle speed range where the motor rotation speed is low, and the vehicle speed is high. The motor output that can be output decreases as the speed increases. That is, in the present embodiment, the main drive motor 16 is driven at about 48 V, outputs a maximum torque of about 200 Nm up to about 1000 rpm, and the torque decreases with an increase in the rotation speed at about 1000 rpm or more. Further, in the present embodiment, the main drive motor 16 is configured to obtain a continuous output of about 20 kW and a maximum output of about 25 kW in the lowest speed range.

  On the other hand, since the induction motor is adopted as the auxiliary drive motor 20, the outputs of the auxiliary drive motors 20 and 21 are extremely small in the low vehicle speed range, as shown by the alternate long and short dash line in FIG. The output increases as the vehicle speed increases, and after the maximum output is obtained near the vehicle speed of about 130 km / h, the motor output decreases. In the present embodiment, the auxiliary drive motors 20 and 21 are driven at about 120 V, and are configured to obtain an output of about 17 kW per vehicle and a total of about 34 kW at a vehicle speed of about 130 km / h. That is, in the present embodiment, the auxiliary drive motors 20 and 21 have a peak torque curve at about 600 to 800 rpm, and a maximum torque of about 200 Nm is obtained.

  The solid line in FIG. 4 shows the total output of the main drive motor 16 and the two auxiliary drive motors 20 and 21. As is clear from this graph, in the present embodiment, the maximum output of about 53 kW is obtained near the vehicle speed of about 130 km / h, and at this vehicle speed, the maximum output satisfies the running condition required in the WLTP test. be able to. In addition, in the solid line of FIG. 4, the output values of the two auxiliary drive motors are summed up even in the low vehicle speed range, but in reality, the auxiliary drive motors are not driven in the low vehicle speed range. That is, only when the vehicle is driven only by the main drive motor 16 at the time of starting and in the low vehicle speed range and a large output is required in the high vehicle speed range (when accelerating the vehicle 1 in the high vehicle speed range, etc.). The secondary drive motor produces an output. In this way, by using the induction motor (sub drive motors 20 and 21) capable of generating a large output in the high rotation range only in the high speed range, the increase of the vehicle weight can be kept low when necessary (predetermined). Sufficient output can be obtained when accelerating at speed or higher).

Next, with reference to FIG. 5, the configuration of the auxiliary drive motor employed in the vehicle drive device 10 according to the first embodiment of the present invention will be described. FIG. 5 is a sectional view schematically showing the structure of the auxiliary drive motor 20. Although the structure of the auxiliary drive motor 20 will be described here, the configuration of the auxiliary drive motor 21 is exactly the same.
As shown in FIG. 5, the auxiliary drive motor 20 is an outer rotor type induction motor that includes a stator 28 and a rotor 30 that rotates around the stator 28.

  The stator 28 has a substantially disk-shaped stator base 28a, a stator shaft 28b extending from the center of the stator base 28a, and a stator coil 28c mounted around the stator shaft 28b. Further, the stator coil 28c is housed in the electric insulating liquid chamber 32, immersed in the electric insulating liquid 32a filled therein, and thereby boiled and cooled.

  The rotor 30 is configured in a substantially cylindrical shape so as to surround the periphery of the stator 28, and has a generally cylindrical rotor body 30a with one end closed, and a rotor arranged on the inner peripheral wall surface of the rotor body 30a. And a coil 30b. The rotor coil 30b is arranged to face the stator coil 28c so that an induced current is generated by the rotating magnetic field generated by the stator coil 28c. The rotor 30 is supported by a bearing 34 attached to the tip of the stator shaft 28b so as to rotate smoothly around the stator 28.

  The stator base 28a is supported by a suspension mechanism (not shown) that suspends the front wheels of the vehicle 1. On the other hand, the rotor body 30a is directly fixed to the wheel (not shown) of the front wheel 2b. An alternating current converted into alternating current by the inverter 20a is passed through the stator coil 28c to generate a rotating magnetic field. An induced current flows through the rotor coil 30b due to this rotating magnetic field, and a driving force for rotating the rotor body 30a is generated. In this way, the driving force generated by the auxiliary drive motor 20 directly rotates the wheel (not shown) of the rear wheel 2a.

6 and 7, the suspension structure of the rear wheel 2a and the arrangement of the capacitors 22 and 23 in the vehicle 1 to which the vehicle drive device 10 according to the first embodiment of the present invention is applied will be described.
FIG. 6 is a perspective view showing the suspension structure of the rear wheel 2a in the vehicle 1 to which the vehicle drive device 10 of the present embodiment is applied. FIG. 7 is a perspective view of the rear wheel portion of the vehicle 1 viewed from the side.

  As shown in FIG. 6, in this embodiment, a torsion beam axle (TBA) type is adopted as the suspension structure of the rear wheel 2a. That is, the rear wheel 2a is suspended by the center beam 8a, the trailing arms 8b attached to both ends of the center beam 8a, the spring 8c, and the shock absorber 8d.

The center beam 8a is a torsion beam extending in the width direction of the vehicle 1, and twisting of the center beam 8a allows the left and right rear wheels 2a to move independently to some extent.
The trailing arms 8b are arm members attached to both ends of the center beam 8a and extending in the front-rear direction of the vehicle 1. The auxiliary drive motor 20 is attached to the rear end of the right trailing arm 8b, and the auxiliary drive motor 21 (not shown in FIG. 6) is attached to the rear end of the left trailing arm 8b. The rear wheel 2a is driven.

  The spring 8c and the shock absorber 8d are attached to the vicinity of both ends of the center beam 8a and the rear end of the trailing arm 8b, respectively, and support the vehicle body while suppressing transmission of vibrations from the respective rear wheels 2a.

  Further, the capacitor 22 for supplying electric power to the auxiliary drive motor 20 provided on the right rear wheel 2a is arranged near the right end of the center beam 8a, and the auxiliary drive motor 21 for the left rear wheel 2a (see FIG. 6). A capacitor 23 for supplying electric power to (not shown) is arranged near the left end of the center beam 8a. As a result, as shown in FIG. 7, the capacitor 23 is arranged at a position overlapping the rear wheel 2a when viewed from the side of the vehicle 1. Similarly, the capacitor 22 arranged on the right side of the vehicle 1 is also arranged at a position overlapping the rear wheel 2a when viewed from the side of the vehicle 1. That is, it is preferable that at least a part of the capacitor is arranged at a position overlapping the rear wheel 2a when viewed from the side of the vehicle 1.

  The electric power from the capacitor 22 is converted into an alternating current by the inverter 20a arranged adjacent to the rear side of the capacitor 22 and supplied to the auxiliary drive motor 20 via the wire harness 22a. Similarly, the electric power from the capacitor 23 is converted into an alternating current by the inverter 21a arranged adjacent to the rear side of the capacitor 23 and is supplied to the auxiliary drive motor 21 (not shown in FIG. 6) via the wire harness 23a. Supplied.

  Here, since the auxiliary drive motors 20 and 21 are driven at a relatively high voltage, the wire harnesses 22a and 23a that supply electric power to them are required to have high withstand voltage. However, since each capacitor and the inverter are arranged in the vicinity of the sub drive motor to which electric power is to be supplied, it is possible to supply electric power to the sub drive motor with a short wire harness. Therefore, even if the withstand voltage of the wire harness is increased, the weight increase due to the provision of the insulating member is slight, and the increase in the weight of the insulating material caused by driving the auxiliary drive motor at a high voltage is suppressed. You can

  According to the vehicle drive device 10 of the first embodiment of the present invention, electric power is supplied from the battery 18 and the capacitors 22 and 23 connected in series to the auxiliary drive motors 20 and 21, which are rear wheel motors, respectively ( 2), each sub-driving motor can be driven at a higher voltage than when driven by the battery 18 alone, and the driving current can be suppressed to a low level. Further, since a relatively high voltage is applied to each of the wire harnesses 22a and 23a for supplying the electric power from the capacitors 22 and 23 to each sub-driving motor, it is necessary to increase the withstand voltage. However, since the electric power is supplied to the auxiliary drive motors 20 and 21 from the capacitors 22 and 23 arranged between the left and right rear wheels 2a of the vehicle 1, the wire harnesses 22a and 23a for supplying the electric power are supplied. It can be shortened (Fig. 6). As a result, even if the withstand voltage of each wire harness is increased, the increase in weight is reduced and the increase in weight due to the insulating material can be suppressed.

  Further, according to the vehicle drive device 10 of the present embodiment, the capacitors 22 and 23 are arranged at a position where at least a part thereof overlaps the rear wheel 2a when viewed from the side of the vehicle 1 (FIG. 7). The wire harnesses 22a and 23a for supplying electric power to the auxiliary drive motors 20 and 21 can be further shortened, and the increase in weight due to the insulating material can be further suppressed.

  Further, according to the vehicle drive device 10 of the present embodiment, since the auxiliary drive motors 20 and 21 which are rear wheel motors are in-wheel motors (FIG. 5), the driving force of the auxiliary drive motors 20 and 21 is set to the rear wheels. Since the rear wheel 2a is directly driven without requiring a power transmission mechanism for transmitting the vehicle 1, the weight of the vehicle 1 can be reduced.

  Further, according to the vehicle drive device 10 of the present embodiment, since the battery 18 is arranged inside the tunnel portion 15, it is possible to secure a sufficient space for accommodating the battery 18. Further, by arranging the battery 18 in this way, the wiring connecting the battery 18 and the capacitors 22 and 23 in series may become relatively long, but since this wiring has a relatively low voltage, it is possible to use an insulating material. An increase in weight can be suppressed.

  Further, according to the vehicle drive device 10 of the present embodiment, since the maximum terminal voltage of the capacitors 22 and 23 is higher than the terminal voltage of the battery 18 (FIG. 3), the capacitors are connected in series. By doing so, the terminal voltage of the battery 18 can be greatly increased. As a result, the auxiliary drive motors 20 and 21 can be driven at a high voltage while using the battery 18 having a relatively low voltage.

Next, a vehicle drive device according to a second exemplary embodiment of the present invention will be described with reference to FIGS. 8 to 10.
FIG. 8 is a layout diagram of a vehicle equipped with the vehicle drive device according to the second embodiment of the present invention. FIG. 9 is a perspective view showing a suspension structure of rear wheels in a vehicle to which the vehicle drive device according to the second embodiment of the present invention is applied. FIG. 10 is a perspective view of a rear wheel portion of the vehicle as viewed from the side.

  The vehicle drive device according to the present embodiment differs from the above-described first embodiment in the structure for transmitting the driving force generated by the engine and the arrangement of the auxiliary drive motor. Therefore, here, only the part of the vehicle drive device according to the present embodiment that is different from the first embodiment will be described, and the same components will be assigned the same reference numerals and description thereof will be omitted.

  As shown in FIG. 8, a vehicle 100 equipped with a vehicle drive device 110 according to a second embodiment of the present invention has an engine 112, which is an internal combustion engine, mounted in the front part of the vehicle in front of the driver's seat. Further, the vehicle 100 is a so-called 4WD (Four Wheel Drive) vehicle in which a pair of left and right front wheels 2b which are main driving wheels and a pair of left and right rear wheels 2a which are auxiliary driving wheels are driven by the driving force of the engine 112. is there. Further, as will be described later, the front wheels 2b are also driven by the main drive motor 116, and the pair of left and right rear wheels 2a which are the sub drive wheels are also driven by the sub drive motor 120.

  A vehicle drive device 110 according to a second embodiment of the present invention mounted on a vehicle 100 drives an engine 112 that drives front wheels 2b and rear wheels 2a, a transmission 114 that is a transmission, and front wheels 2b and rear wheels 2a. It has a main drive motor 116, a battery 118, and a control device 124 that is a controller. Further, the vehicle drive device 110 has a sub drive motor 120 that is a rear wheel motor that drives the left and right rear wheels 2a, and a capacitor 122 disposed in the vicinity thereof.

  The engine 112 is an internal combustion engine for generating driving force for the front wheels 2b that are the main driving wheels and the rear wheels 2a that are the auxiliary driving wheels of the vehicle 100. In the present embodiment, the engine 112 arranged in the front part of the vehicle 100 drives the front wheels 2b via a transmission 114 and a differential gear (not shown). Further, a part of the driving force generated by the engine 112 is taken out by a power take-off (PTO) 117a and is also transmitted to the left and right rear wheels 2a.

  The transmission 114 is a multi-stage transmission that converts the rotational speed of the output shaft of the engine 112 and outputs it. The output of the transmission 114 is transmitted to each of the front wheels 2b via a differential gear (not shown). Further, a part of the output power of the transmission 114 is taken out by a power take-off 117a, and the taken out output is left and right via a propeller shaft 117b, a coupling 117c which is an electromagnetic clutch, and a rear differential gear 117d for rear wheels. It is transmitted to the rear wheel 2a. Further, the propeller shaft 117b is passed through a tunnel portion 115 formed in the center of a lower portion of the vehicle 100 so as to extend in the front-rear direction, and a coupling 117c is connected to a rear end portion thereof. The coupling 117c transmits the input driving force to the rear differential gear 117d.

  The main drive motor 116 is an electric motor for generating a driving force for the main drive wheels and the auxiliary drive wheels, is provided on the vehicle body of the vehicle 100, and is arranged laterally of the engine 112 and adjacent to the engine 112. And functions as a vehicle body side motor. In addition, an inverter 116a is arranged in the tunnel portion 115 of the vehicle 100. The inverter 116a converts the DC voltage of the battery 118 into an AC voltage and supplies the AC voltage to the main drive motor 116. Further, as shown in FIG. 8, the main drive motor 116 is connected in series with the engine 112, and the driving force generated by the main drive motor 116 is also transmitted to the front wheels 2b via the transmission 114.

  Further, part of the driving force generated by the main drive motor 116 is also taken out by the power take-off 117a and transmitted to the rear wheel 2a. In the present embodiment, as the main drive motor 116, a 25 kW permanent magnet electric motor (permanent magnet synchronous electric motor) driven by 48 V is adopted. Further, in the present embodiment, up to 50% of the power generated by the engine 112 and the main drive motor 116 is transmitted to the rear wheel side by the power take-off 117a and the coupling 117c.

  The battery 118 is a power storage device that mainly stores electric energy for operating the main drive motor 116, and is arranged in the tunnel 115 behind the inverter 116a. Furthermore, in the present embodiment, as the battery 118, a 48V, 3.5 kWh lithium ion battery (LIB) is used.

  Next, the auxiliary drive motor 120 is provided so as to generate a driving force for the rear wheel 2a, which is an auxiliary drive wheel, and is integrated with the coupling 117c and the rear differential gear 117d for the rear wheel. Therefore, the auxiliary drive motor 120 is arranged between the left and right rear wheels 2a of the vehicle 100. Further, the auxiliary drive motor 120 is an on-board motor provided on the vehicle body side of the vehicle 100, and the driving force is transmitted to the left and right rear wheels 2a via the rear differential gear 117d. Further, as shown in FIG. 8, the current from the capacitor (CAP) 122 is supplied to the sub drive motor 120 after being converted into alternating current by the sub drive motor inverter 120a.

  The capacitor 122 is provided to store the electric power regenerated by the auxiliary drive motor 120. As shown in FIG. 8, the capacitor 122 and the inverter 120a are arranged adjacent to the vicinity of the coupling 117c, the rear differential gear 117d, and the auxiliary drive motor 120, which are arranged in the center of the vehicle 100 in the width direction. Further, the capacitor 122 is connected in series with the battery 118, and the electric power from the capacitor 122 is supplied to the sub drive motor 120 via the inverter 120a and the wire harness 122a.

  As a result, the sub drive motor 120 is driven at a voltage higher than the terminal voltage of the battery 118. Further, the capacitor 122 is configured to store charge at a higher voltage than the battery 118. A high voltage DC / DC converter 126a, which is a voltage converter, is connected between the battery 118 and the capacitor 122. The high-voltage DC / DC converter 126a enables bidirectional charging between the battery 118 and the capacitor 122. Further, a low-voltage DC / DC converter 126b is connected between the battery 118 and a 12V electric component (not shown) of the vehicle 100, and the electric charge accumulated in the battery 118 is reduced to 12V to be an electric component or the like. Can be supplied.

  On the other hand, as shown in FIG. 8, the control device 124 is configured to control the engine 112, the main drive motor 116, and the auxiliary drive motor 120 to execute the electric motor traveling mode and the internal combustion engine traveling mode. Specifically, the control device 124 can be configured by a microprocessor, a memory, an interface circuit, a program for operating these (above, not shown), and the like.

  Next, a suspension structure of the rear wheel 2a and an arrangement of the capacitors 122 in the vehicle 100 to which the vehicle drive device 110 according to the second embodiment of the present invention is applied will be described with reference to FIGS. 9 and 10.

  As shown in FIG. 9, also in this embodiment, a torsion beam axle (TBA) type is adopted as the suspension structure of the rear wheel 2a, and the rear wheel 2a has a center beam 8a, a trailing arm 8b, a spring 8c, It is suspended by the shock absorber 8d.

  Further, the propeller shaft 117b extending from the front part of the vehicle 100 passes under the center beam 8a and is connected to a coupling 117c arranged behind the center beam 8a. The output from the coupling 117c is input to a rear differential gear 117d that is integrally provided on the rear side of the coupling 117c. On the other hand, the output of the auxiliary drive motor 120 integrally provided on the rear side of the rear differential gear 117d is also input to the rear differential gear 117d. The driving force input to the rear differential gear 117d is transmitted to the left and right rear wheels 2a by drive shafts 117e extending in the width direction of the vehicle 100 from both side surfaces of the rear differential gear 117d.

  The capacitor 122 that supplies electric power to the sub drive motor 120 is arranged between the left and right rear wheels 2a and near the left end of the center beam 8a. As a result, as shown in FIG. 10, the capacitor 122 is arranged at a position overlapping the rear wheel 2a when viewed from the side of the vehicle 100. That is, at least a part of the capacitor is preferably arranged at a position overlapping the rear wheel 2a when viewed from the side of the vehicle 100. Further, according to this arrangement, the capacitor 122 is located between the rear differential gear 117d and the rear wheel 2a and between the coupling 117c and the rear wheel 2a. Note that the present invention can be configured such that two capacitors are provided as in the first embodiment, and these capacitors are arranged on both sides of the coupling 117c, the rear differential gear 117d, and the auxiliary drive motor 120.

  Further, the electric power from the capacitor 122 is converted into an alternating current by the inverter 120a arranged adjacent to the rear side of the capacitor 122, and is supplied to the sub drive motor 120 via the wire harness 122a. Here, since the sub drive motor 120 is driven at a relatively high voltage, the wire harness 122a that supplies electric power to the sub drive motor 120 is required to have a high withstand voltage. However, since the capacitor 122 and the inverter 120a are arranged in the vicinity of the sub drive motor 120 to which electric power is to be supplied, it is possible to supply electric power to the sub drive motor with a short wire harness. Therefore, even if the withstand voltage of the wire harness is increased, the weight increase due to the provision of the insulating member is slight, and the increase in the weight of the insulating material caused by driving the auxiliary drive motor at a high voltage is suppressed. You can

  According to the vehicle drive device 110 of the second embodiment of the present invention, since the capacitor 122 is arranged between the rear differential gear 117d and the rear wheel 2a (FIG. 9), the left and right rear wheels 2a are rear differentials. Also in vehicle 100 driven via gear 117d, capacitor 122 can be arranged near rear wheel 2a. As a result, the wire harness 122a that supplies power to the auxiliary drive motor 120 that is a rear wheel motor can be shortened, and an increase in weight of the wire harness 122a due to the insulating material can be suppressed.

  Further, according to the vehicle drive device 110 of the present embodiment, since the capacitor 122 is arranged between the coupling 117c and the rear wheel 2a (FIG. 9), the left and right rear wheels 2a are connected via the coupling 117c. Also in vehicle 100 driven by the drive, capacitor 122 can be arranged near rear wheel 2a. As a result, the wire harness 122a that supplies power to the auxiliary drive motor 120 that is a rear wheel motor can be shortened, and an increase in weight of the wire harness 122a due to the insulating material can be suppressed.

  Although the preferred embodiment of the present invention has been described above, various modifications can be made to the above-described embodiment. In particular, in the above-described embodiment, the rear wheel motor is made to function as the auxiliary drive motor, but the present invention can also be applied to a vehicle drive device in which the rear wheel motor functions as the main drive motor. Further, in the above-described embodiment, the power of the engine and the main drive motor drives the front wheels, but the present invention can also be applied to a vehicle drive device that does not have an engine and / or a motor that drives the front wheels. .

1 vehicle 2a rear wheels (auxiliary drive wheels)
2b front wheel (main drive wheel)
8a Center beam 8b Trailing arm 8c Spring 8d Shock absorber 10 Vehicle drive device 12 Engine (internal combustion engine)
14 Transmission (transmission)
15 tunnel section 16 main drive motor 16a inverter 18 battery (electric storage device)
20 Sub drive motor (in-wheel motor)
20a Inverter 21 Sub drive motor (in-wheel motor, rear wheel motor)
21a Inverter 22 Capacitor 22a Wire harness 23 Capacitor 23a Wire harness 24 Control device (controller)
25 Electrical Equipment 26a High Voltage DC / DC Converter (Voltage Converter)
26b Low-voltage DC / DC converter 28 Stator 28a Stator base 28b Stator shaft 28c Stator coil 30 Rotor 30a Rotor body 30b Rotor coil 32 Electrical insulating liquid chamber 32a Electrical insulating liquid 34 Bearing 100 Vehicle 110 Vehicle drive device 112 Engine (internal combustion engine)
114 Transmission
115 tunnel section 116 main drive motor 116a inverter 117a power take-off 117b propeller shaft 117c coupling 117d rear differential gear 117e drive shaft 118 battery (electric storage device)
120 Sub drive motor (rear wheel motor)
120a Inverter 122 Capacitor 122a Wire harness 124 Control device (controller)
126a High-voltage DC / DC converter (voltage converter)
126b Low voltage DC / DC converter

Claims (7)

A drive device for a vehicle that drives wheels using a motor,
A rear wheel motor that is arranged between the rear wheels of the vehicle and drives the rear wheels;
A battery that stores electrical energy for driving this rear wheel motor,
A capacitor storing electric energy for driving the rear wheel motor,
A wire harness that supplies electric power from the capacitor to the rear wheel motor,
The rear wheel motor is supplied with power from the battery and the capacitor connected in series,
The vehicle drive device, wherein the capacitor is disposed between the left and right rear wheels of the vehicle.   The vehicle drive device according to claim 1, wherein at least a part of the capacitor is arranged at a position overlapping the rear wheel when viewed from the side of the vehicle.   3. The vehicle drive device according to claim 1, wherein the rear wheel motor is an in-wheel motor provided on each of the left and right rear wheels of the vehicle.   Further, a rear differential gear that is arranged between the left and right rear wheels and that transmits power to the left and right rear wheels is provided, and the capacitor is arranged between the rear differential gear and the rear wheels. The vehicle drive device according to any one of claims 1 to 3.   Further, it is arranged between the left and right rear wheels and in front of the rear differential gear, and has a coupling for transmitting the input driving force to the rear differential gear, and the capacitor is The vehicle drive device according to claim 4, wherein the vehicle drive device is arranged between the rear wheel and the rear wheel.   6. The battery according to claim 1, wherein the battery is arranged in a tunnel portion provided in a lower portion of the vehicle or in a rear portion of the vehicle so as to extend in a front-rear direction of the vehicle. Vehicle drive.   The vehicle drive device according to any one of claims 1 to 6, wherein the maximum terminal voltage of the capacitor is higher than the terminal voltage of the battery.

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