Vehicle drive device

Abstract

To provide a vehicular driving device equipped with two rotating electric machines acting as driving force sources for wheels, which can drive the rotating electric machines at higher efficiency.SOLUTION: A control device of a vehicular driving device can execute a first EV mode, a second EV mode and a parallel mode. In a low vehicle speed region S1 in an operation region of the vehicle, the first EV mode is executed in a first region F1 where driving force is low, and the second EV mode is executed in a second region F2 where driving force is high. In a middle vehicle speed region S2, the first EV mode is executed in the first region F1, the second EV mode is executed in the second region F2 and the parallel mode is executed in a third region F3 where driving force is higher than in the second region F2. In a high vehicle speed region S3, the first EV mode is executed in the first region F1, the second EV mode is executed in the second region F2 and the parallel mode can be executed in all regions including the third region F3 regardless of magnitude of driving force.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vehicle drive device including a first rotating electric machine and a second rotating electric machine. [Background technology]

[0002] For example, in a vehicle drive device for a series-parallel hybrid vehicle equipped with two rotating electric machines, one rotating electric machine is used as a generator, and the other rotating electric machine and an internal combustion engine obtain the driving force required to drive the wheels. JP 2017-177975 A discloses a vehicle drive device for a hybrid vehicle that uses two rotating electric machines both as generators and as electric motors. This vehicle drive device is capable of a two-motor EV (electric vehicle) mode in which both of the two rotating electric machines are used as a driving force source for the wheels, a one-motor EV mode in which only one rotating electric machine is used as a driving force source for the wheels, a parallel hybrid mode in which the rotating electric machine and the internal combustion engine drive the wheels, and a series hybrid mode in which one rotating electric machine is generated by the power of the internal combustion engine and the other rotating electric machine is driven by the electric power. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-177975 A Summary of the Invention [Problem to be solved by the invention]

[0004] In addition, in the vehicle drive device of the above publication, the entire driving range of the one-motor EV is included inside the driving range of the two-motor EV. For example, when the vehicle speed exceeds the range set in the driving range of the one-motor EV, the mode switches to the two-motor EV mode even if only a relatively low driving force is required. However, when outputting the same driving force, driving two rotating electric machines often results in a higher total loss than driving one rotating electric machine.

[0005] In view of the above background, it is desirable to provide a technique for driving the rotating electric machines with higher efficiency in a vehicle drive device that includes two rotating electric machines that serve as a driving force source for the wheels. [Means for solving the problem]

[0006] In view of the above-mentioned problems, one aspect of a vehicle drive device includes an output member drivingly connected to a wheel, a first rotating electric machine having a first rotor, a second rotating electric machine having a second rotor, an input member drivingly connected to an internal combustion engine, a first transmission system that drivingly connects the first rotor and the output member, a second transmission system that drivingly connects the second rotor and the output member, a third transmission system that drivingly connects the input member and the first rotor, a first engagement device that connects and disconnects power transmission in the first transmission system, and a power transmission mechanism that connects and disconnects the power transmission mechanism in the third transmission system. a control device that controls the first rotating electric machine, the second rotating electric machine, the first engagement device, and the second engagement device, wherein a mode in which the first engagement device and the second engagement device are in a disengaged state and the driving force of the second rotating electric machine is transmitted to the output member is defined as a first EV mode, and a mode in which the first engagement device is in an engaged state and the second engagement device is in a disengaged state and the driving forces of the first rotating electric machine and the second rotating electric machine are transmitted to the output member is defined as a second EV mode, a parallel mode in which the internal combustion engine, the first rotating electric machine, and the second rotating electric machine are engaged and the driving forces of the internal combustion engine, the first rotating electric machine, and the second rotating electric machine are transmitted to the output member; and the control device is capable of executing the first EV mode, the second EV mode, and the parallel mode. In an operating range of the vehicle defined by vehicle speed and driving force, a low vehicle speed range is set on the lowest vehicle speed side, a high vehicle speed range is set on the highest vehicle speed side, and a medium vehicle speed range is set therebetween. In the low vehicle speed range, the first EV mode is executed in a first range where the driving force is relatively low, and the second EV mode is executed in a second range where the driving force is high. In the medium vehicle speed range, the first EV mode is executed in the first range, the second EV mode in the second range, and the parallel mode is executed in a third range where the driving force is higher than that in the second range. In the high vehicle speed range, the first EV mode is executed in the first range and the second EV mode in the second range, and the parallel mode is executable regardless of the driving force in all ranges including the third range.

[0007] When the same driving force is output, in the case where two rotating electric machines are driven, a loss occurs in each rotating electric machine, and therefore the energy efficiency of the vehicle drive device as a whole is likely to decrease compared to driving only one rotating electric machine. However, according to the present configuration, the first EV mode is executed in the first region where the driving force is relatively low for each vehicle speed, and the second EV mode is executed in the second region where the driving force is relatively high. That is, in the region where the driving force is low at the same vehicle speed, the first EV mode is executed using only the second rotating electric machine without using the first rotating electric machine even in the high vehicle speed region, so that the energy efficiency of the vehicle drive device as a whole is likely to be improved. In addition, the maximum torque of the second rotating electric machine is set so that the maximum torque of the first EV mode is smaller than the maximum torque of the second EV mode. Therefore, the second rotating electric machine can be a rotating electric machine with characteristics suitable for a relatively low torque region. In this case, the second rotating electric machine can be efficiently driven in a wide vehicle speed range in the normal torque range where high torque is not required. In this respect, the energy efficiency of the vehicle drive device is also likely to be improved. In addition, the region where the driving force is high can be handled by executing the second EV mode or the parallel mode, which uses both the first rotating electric machine and the second rotating electric machine. Since such a situation where the driving force is high occurs infrequently, even if the energy efficiency decreases in the second EV mode or the parallel mode, the decrease in energy efficiency in actual usage conditions is limited. Thus, according to this configuration, in a vehicle drive device having two rotating electric machines that serve as a driving force source for the wheels, it is possible to drive the rotating electric machines with higher efficiency.

[0008] Further, in one embodiment, a vehicle drive device in consideration of the above includes a first rotating electric machine having a first rotor arranged on a first axis, a second rotating electric machine having a second rotor arranged on a second axis that is a separate axis parallel to the first axis, an output member that is drivingly connected to wheels and arranged on a third axis that is a separate axis parallel to the first axis and the second axis, an input member that is drivingly connected to an internal combustion engine and arranged on a fourth axis that is a separate axis parallel to the first axis, the second axis, and the third axis, a counter gear mechanism that is arranged on a fifth axis that is a separate axis parallel to the first axis, the second axis, the third axis, and the fourth axis, and includes a first counter gear and a second counter gear, a first transmission system that includes a plurality of gears including the counter gear mechanism and drivingly connects the first rotor and the output member, and the second transmission system includes a plurality of gears including a gear mechanism and drivingly connects the second rotor and the output member, a third transmission system includes a plurality of gears and drives the input member and the first rotor, a first engagement device that connects and disconnects power transmission in the first transmission system, and a second engagement device that connects and disconnects power transmission in the third transmission system, wherein a gear ratio in the first transmission system is set to a gear ratio at which a maximum speed of the output member can be outputted by a maximum rotational speed of the first rotating electric machine, a gear ratio in the second transmission system is set to a gear ratio at which a maximum speed of the output member can be outputted by a maximum rotational speed of the second rotating electric machine, and a combined gear ratio of the third transmission system and the first transmission system is set to a gear ratio at which a maximum speed of the output member can be outputted by a maximum rotational speed of the internal combustion engine.

[0009] According to this configuration, a vehicle drive device capable of EV running (so-called one-motor EV running) using the second rotating electric machine as a driving force source can be realized by power transmission through the second transmission system. Also, a vehicle drive device capable of EV running (so-called two-motor EV running) using the first rotating electric machine and the second rotating electric machine as a driving force source can be realized by power transmission through the first transmission system and the second transmission system. Also, a vehicle drive device capable of hybrid running (so-called parallel running) using the first rotating electric machine, the second rotating electric machine, and an internal combustion engine as driving force sources can be realized by power transmission through the first transmission system, the second transmission system, and the third transmission system. And, by setting the gear ratio in the first transmission system, the gear ratio in the second transmission system, and the combined gear ratio of the third transmission system and the first transmission system as described above, one-motor EV running, two-motor EV running, and parallel running are all possible in the entire vehicle speed range of the vehicle. In other words, in the range where the driving force is low at the same vehicle speed, the vehicle drive device of this configuration is capable of one-motor EV driving using only the second rotating electric machine, without using the first rotating electric machine or the internal combustion engine, even at high vehicle speeds, making it easier to improve the energy efficiency of the vehicle drive device as a whole.

[0010] Further features and advantages of the drive device for a vehicle will become apparent from the following description of an exemplary and non-limiting embodiment, which is given with reference to the drawings. [Brief description of the drawings]

[0011] [Figure 1] FIG. 13 is a block diagram illustrating another example of a vehicle drive device. [Diagram 2] FIG. 2 is a diagram showing an example of an operating region map of a vehicle drive device; [Diagram 3] FIG. 13 is a diagram showing the relationship between the operating region and efficiency of a rotating electric machine of a vehicle drive device of a comparative example. [Figure 4] FIG. 13 is a diagram showing the relationship between the operating range and efficiency of a rotating electric machine of a vehicle drive device. [Diagram 5] FIG. 1 is a skeleton diagram showing a specific configuration example of a vehicle drive device; [Figure 6] A state transition diagram showing the relationship between the engagement states of the first engagement device and the second engagement device and the operation mode of the vehicle drive device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of a vehicle drive device will be described with reference to the drawings. The block diagram of Fig. 1 shows a vehicle drive device 100 for a so-called hybrid vehicle. The vehicle drive device 100 includes two rotating electric machines (a first rotating electric machine MG1 and a second rotating electric machine MG2) and an internal combustion engine EG as a driving force source for an output member OUT.

[0013] In this specification, "driving connection" refers to a state in which two or more rotating elements are connected so as to be able to transmit a driving force (synonymous with torque), and includes a state in which the two rotating elements are connected so as to rotate integrally, or a state in which the two rotating elements are connected so as to be able to transmit a driving force via one or more transmission members. Such transmission members include various members (e.g., shafts, gear mechanisms, belts, chains, etc.) that transmit rotation at the same speed or at a variable speed, and may also include engagement devices (e.g., friction engagement devices, meshing engagement devices, etc.) that selectively transmit rotation and driving force.

[0014] In this specification, the term "rotating electric machine" is used as a concept including a motor, a generator, and a motor-generator that functions as both a motor and a generator as necessary. Therefore, the first rotating electric machine MG1 and the second rotating electric machine MG2 have a function as a motor that receives a supply of electric power to generate power, and a function as a generator that receives a supply of power to generate power. Therefore, the first rotating electric machine MG1 and the second rotating electric machine MG2 are each electrically connected to a DC power source BAT. As the DC power source BAT, various known power storage devices such as a battery or a capacitor can be used.

[0015] The vehicle drive device 100 includes an output member OUT that is drivingly connected to the wheels W, a first rotating electric machine MG1 having a first rotor 10, a second rotating electric machine MG2 having a second rotor 20, a first transmission system 1 that drivingly connects the first rotor to the output member, a second transmission system 2 that drivingly connects the second rotor 20 to the output member OUT, a first engagement device CL1 that connects and disconnects the power transmission in the first transmission system 1, and a control device CTL that controls the first rotating electric machine MG1, the second rotating electric machine MG2, and the engagement device (first engagement device CL1). The vehicle drive device 100 also includes an input member IN that is drivingly connected to the internal combustion engine EG, a third transmission system 3 that drivingly connects the input member IN to the first rotor 10, and a second engagement device CL2 that connects and disconnects the power transmission in the third transmission system 3. The control device CTL further controls the second engagement device CL2. Although not shown in FIG. 1, this does not prevent the control device CTL from also controlling the internal combustion engine EG.

[0016] In the vehicle drive device 100, a mode in which the first engagement device CL1 and the second engagement device CL2 are in a disengaged state and the driving force of the second rotating electric machine MG2 is transmitted to the output member OUT is defined as a first EV mode. A mode in which the first engagement device CL1 is in an engaged state and the second engagement device CL2 is in a disengaged state and the driving forces of the first rotating electric machine MG1 and the second rotating electric machine MG2 are transmitted to the output member OUT is defined as a second EV mode. That is, if the second engagement device CL2 is in a disengaged state, the input member IN is not drivingly connected to both the first rotating electric machine MG1 and the second rotating electric machine MG2, and the first EV mode and the second EV mode can be realized depending on the state of the first engagement device CL1. The control device CTL can execute the first EV mode and the second EV mode.

[0017] In addition to the first EV mode and the second EV mode, the vehicle drive device 100 can also realize a parallel mode (parallel hybrid mode) in which the first engagement device CL1 and the second engagement device CL2 are in an engaged state and the driving forces of the internal combustion engine EG, the first rotating electric machine MG1, and the second rotating electric machine MG2 are transmitted to the output member OUT. The vehicle drive device 100 can also realize a series mode (series hybrid mode) in which the first engagement device CL1 is in a disengaged state and the second engagement device CL2 is in an engaged state, the first rotating electric machine MG1 generates electricity using the driving force of the internal combustion engine EG, and the driving force of the second rotating electric machine MG2 is transmitted to the output member OUT. That is, the control device CTL can further execute the parallel mode and the series mode.

[0018] In the vehicle drive device 100, the first rotating electric machine MG1 functions as a generator that generates electricity using the torque of the internal combustion engine EG, charges the DC power supply BAT, or supplies power to drive the second rotating electric machine MG2. However, the first rotating electric machine MG1 may also function as a motor that generates driving force (synonymous with "torque") by powering when the vehicle is running at high speed or when the internal combustion engine EG is started. The internal combustion engine EG is a prime mover (gasoline engine, diesel engine, etc.) that is driven by the combustion of fuel to extract power. The second rotating electric machine MG2 mainly functions as a motor that generates driving force for running the vehicle. However, when the vehicle is decelerating, the second rotating electric machine MG2 may also function as a generator that regenerates the inertial force of the vehicle as electric energy.

[0019] FIG. 2 shows an example of an operational region map of the vehicle drive device 100. The region hatched with diagonal lines from the upper right to the lower left in the figure indicates an operational region by one rotating electric machine (one-motor EV operational region, first operational region M1). In this embodiment, this corresponds to the operational region by the second rotating electric machine MG2. As described above, in the first EV mode, the first engagement device CL1 and the second engagement device CL2 are in a disengaged state, and the driving force of the second rotating electric machine MG2 is transmitted to the output member OUT. Therefore, the first operational region M1 is an operational region in which the first EV mode is executed.

[0020] The area hatched with horizontal lines in the figure indicates the operation area (two-motor EV operation area, second operation area M2) by two rotating electric machines. In this embodiment, this corresponds to the operation area by both the first rotating electric machine MG1 and the second rotating electric machine MG2. As described above, in the second EV mode, the first engagement device CL1 is engaged and the second engagement device CL2 is disengaged, and the driving forces of the first rotating electric machine MG1 and the second rotating electric machine MG2 are transmitted to the output member OUT. Therefore, the second operation area M2 is an operation area in which the second EV mode is executed.

[0021] The area hatched with diagonal lines from the upper left to the lower right in the figure indicates an operating area (parallel hybrid operating area, parallel operating area, third operating area H) where the driving force from the internal combustion engine EG is used. In this embodiment, in the parallel mode, the first engagement device CL1 and the second engagement device CL2 are engaged, and the driving forces of the internal combustion engine EG, the first rotating electric machine MG1, and the second rotating electric machine MG2 are transmitted to the output member OUT. Therefore, the third operating area H is an operating area where the parallel mode is executed. As shown in FIG. 2, the third operating area H overlaps with the first operating area M1 and the second operating area M2 when the vehicle speed is equal to or higher than the first speed V1.

[0022] In the series mode, the first rotating electric machine MG1 functions as a generator and the second rotating electric machine MG2 functions as an electric motor, so that the second rotating electric machine MG2 serves as the driving force source for the wheels W (output member OUT). Therefore, the first operating region M1 can be said to be an operating region in which the series mode is also executed.

[0023] In other words, in the vehicle operation range defined by the vehicle speed and the driving force, a low vehicle speed range S1 is set on the lowest vehicle speed side, a high vehicle speed range S3 is set on the highest vehicle speed side, and a medium vehicle speed range S2 is set between them. In the low vehicle speed range S1, the first EV mode is executed in the first range F1 where the driving force is relatively low, and the second EV mode is executed in the second range F2 where the driving force is high. In the medium vehicle speed range S2, the first EV mode is executed in the first range F1, the second EV mode is executed in the second range F2, and the parallel mode is executed in the third range F3 where the driving force is higher than that of the second range F2. In the high vehicle speed range S3, the first EV mode is executed in the first range F1 and the second EV mode is executed in the second range F2, and the parallel mode can be executed in all ranges including the third range F3 regardless of the driving force.

[0024] As shown in Fig. 2, the maximum vehicle speed at which the first EV mode is executed and the maximum vehicle speed at which the second EV mode is executed are the same second speed V2. At all vehicle speeds from zero to the maximum vehicle speed (second speed V2), that is, at each vehicle speed included in the vehicle speed range at which both the first EV mode and the second EV mode are executed, the maximum torque in the first EV mode is smaller than the maximum torque in the second EV mode. In Fig. 2, the driving force [N] is shown, but the same is true for torque [Nm]. The driving force that is required to be transmitted to the output member OUT is the required driving force, and the control device CTL executes the second EV mode when the required driving force becomes higher than the maximum torque (maximum driving force) in the first EV mode at each vehicle speed.

[0025] When the same driving force is output, in the case where two rotating electric machines are driven, a loss occurs in each rotating electric machine, and therefore the energy efficiency of the vehicle drive device 100 as a whole is likely to decrease compared to driving only one rotating electric machine. However, as shown in FIG. 2, in this embodiment, the first EV mode is executed in the first region F1 where the required driving force is relatively low for each vehicle speed, and the second EV mode is executed in the second region F2 where the required driving force is relatively high. That is, in the region where the required driving force is low at the same vehicle speed, the first EV mode is executed using only the second rotating electric machine MG2 without using the first rotating electric machine MG1 even in the high vehicle speed region. That is, in the region where the required driving force is relatively low (first region F1) in the entire vehicle speed range in the vehicle operation region defined by the vehicle speed and the driving force, the first EV mode is executed. Therefore, the energy efficiency of the vehicle drive device 100 as a whole is likely to be improved. In addition, the maximum torque of the second rotating electric machine MG2 is set so that the maximum torque of the first EV mode is smaller than the maximum torque of the second EV mode. Therefore, the second rotating electric machine MG2 can be a rotating electric machine with characteristics suitable for a relatively low torque range. In this case, the second rotating electric machine MG2 can be efficiently driven over a wide vehicle speed range in the normal torque range where high torque is not required. This also makes it easier to improve the energy efficiency of the vehicle drive device 100.

[0026] 3 shows the relationship between the operating region and efficiency of the rotating electric machine of the vehicle drive device of the comparative example, and illustrates a form in which a driving force is output by one rotating electric machine in the entire operating region (motor operating region E) which is a combination of the first operating region M1 and the second operating region M2. In contrast, in the vehicle drive device 100 of the present embodiment, as described above with reference to FIG. 2, the second rotating electric machine MG2 outputs a driving force in the first operating region M1, and the driving force corresponding to the entire motor operating region E is output by both the first rotating electric machine MG1 and the second rotating electric machine MG2 (see FIG. 4). In both FIG. 3 and FIG. 4, the efficient operating region of the rotating electric machine is shown as a high efficiency region A, and the operating region less efficient than the high efficiency region A is shown as a reduced efficiency region B.

[0027] As shown in Fig. 3, a single rotating electric machine that outputs driving force over the entire motor operation region E is naturally configured to be capable of handling high driving forces. For this reason, the high efficiency region A, which is the most efficient operation region, is located on the side of relatively high driving forces. The region shown by diagonal hatching in Figs. 3 and 4 is the so-called regular torque region G. As shown in Fig. 3, if a single rotating electric machine is used to cover the entire motor operation region E, the high efficiency region A is likely to fall outside the regular torque region G. Therefore, the overall efficiency of the vehicle drive device is likely to decrease even if a high-performance rotating electric machine is installed.

[0028] 4, most of the first operating region M1, which is the operating region of only the second rotating electric machine MG2, is the normal torque region. Most of the high efficiency region A of the second rotating electric machine MG2 is included in the normal torque region G. Therefore, the second rotating electric machine MG2 can be used with high efficiency, and the overall efficiency of the vehicle drive device 100 can be easily improved.

[0029] Note that a region where the required driving force is high can be handled by executing the second EV mode, which uses both the first rotating electric machine MG1 and the second rotating electric machine MG2. Since such a situation where the required driving force is high does not occur frequently, even if the energy efficiency decreases in the second EV mode, the decrease in energy efficiency in actual usage conditions is considered to be limited.

[0030] In addition, the vehicle drive device 100 is drivingly connected to the internal combustion engine EG. Therefore, in an operating range where the energy efficiency of the rotating electric machine is reduced, the driving force of the internal combustion engine EG is used to easily increase the overall efficiency of the vehicle drive device 100. In general, the internal combustion engine EG is efficient at high revolutions, and the energy efficiency is easily increased when the vehicle speed is high. As shown in Fig. 3 and Fig. 4, the energy efficiency of the rotating electric machine decreases in a high vehicle speed range, but in that range, the overall energy efficiency of the vehicle drive device 100 is easily increased by using the driving force of the internal combustion engine EG.

[0031] As described above with reference to FIG. 2, in the second vehicle driving device 100B, in addition to the first EV mode and the second EV mode, the parallel mode can be executed. The maximum vehicle speed at which the parallel mode is executed is the second speed V2, which is the same as the maximum vehicle speed at which the first EV mode and the second EV mode are executed. On the other hand, in the region (high vehicle speed region S3) from the first speed V1 to the second speed V2, which is lower than the second speed V2, the first operation region M1, which is the operation region of the first EV mode, overlaps with the third operation region H, which is the operation region of the parallel mode, and the second operation region M2, which is the operation region of the second EV mode, overlaps with the third operation region H. In other words, in the operation region of the first speed V1 or higher, not only the parallel mode is executable, but also the first EV mode and the parallel mode can be selectively executed, and the second EV mode and the parallel mode can be selectively executed.

[0032] That is, since the maximum vehicle speed at which the parallel mode is executed is the same as the maximum vehicle speed at which the first EV mode and the second EV mode are executed, the operating region at which the parallel mode is executed overlaps with the operating region at which the first EV mode and the second EV mode are executed. Therefore, the first EV mode and the parallel mode, or the second EV mode and the parallel mode can be appropriately selected according to the state of charge (SOC) of the DC power supply that supplies power to the rotating electric machine, etc. Note that this does not prevent a mode in which the maximum vehicle speed at which the parallel mode is executed is higher than the maximum vehicle speed at which the first EV mode and the second EV mode are executed.

[0033] As shown in FIG. 2, when the vehicle speed does not change and the required driving force of the vehicle increases, and the operating point of the vehicle drive device 100 moves from the first operating point Q1 in the first operating region M1 to the second operating point Q2 in the second operating region M2, the operating mode shifts from the first EV mode to the second EV mode. Furthermore, when the required driving force increases and moves to an operating point higher than the second operating point Q2, the operating mode shifts from the second EV mode to the parallel mode. As described above, in the vehicle drive device 100 of this embodiment, the maximum vehicle speed at which the first EV mode is executed, the maximum vehicle speed at which the second EV mode is executed, and the maximum vehicle speed at which the parallel mode is executed are the same second speed V2. At each vehicle speed included in the vehicle speed range at which both the first EV mode and the second EV mode are executed, the maximum torque in the first EV mode is smaller than the maximum torque in the second EV mode. The control device CTL executes the second EV mode when the required driving force, which is the driving force that is requested to be transmitted to the output member OUT, becomes higher than the maximum torque of the first EV mode at each vehicle speed, and executes the parallel mode when the required driving force becomes higher than the maximum torque of the second EV mode at each vehicle speed.

[0034] On the other hand, when the vehicle speed increases without changing the required driving force of the vehicle from the state in which the first EV mode is being executed, the vehicle can be shifted to the parallel mode when the vehicle speed becomes equal to or higher than the first speed V1 without passing through the second EV mode from the first EV mode. Note that when the vehicle speed increases together with the required driving force of the vehicle from the state in which the first EV mode is being executed, the vehicle may be shifted to the parallel mode via the second EV mode from the first EV mode. In this embodiment, the first EV mode can be executed using only the driving force of the second rotating electric machine MG2 without using the driving force of the first rotating electric machine MG1 until immediately before the shift to the parallel mode, so that the energy efficiency of the vehicle drive device 100 as a whole can be easily improved.

[0035] As described above, the vehicle drive device 100 can also execute the series mode. Therefore, even if the state of charge (SOC) of the DC power supply that supplies power to the rotating electric machine decreases, the vehicle can be driven appropriately while maintaining a driving force equivalent to that in the first EV mode.

[0036] As described above, when two rotating electric machines are used as driving power sources for the wheels W, a good balance of the driving forces of the two rotating electric machines reduces the control load on the control device CTL. Furthermore, when the series mode is executed, the second rotating electric machine MG2 can be sufficiently driven by the energy generated by the first rotating electric machine MG1. Therefore, it is preferable that the first rotating electric machine MG1 and the second rotating electric machine MG2 have the same electrical specifications. In other words, it is preferable that the first rotating electric machine MG1 and the second rotating electric machine MG2 are rotating electric machines having the same maximum torque and maximum rotation speed. Naturally, the first rotating electric machine MG1 and the second rotating electric machine MG2 may be rotating electric machines having different maximum torque and maximum rotation speed.

[0037] The above describes a technique for driving the rotating electric machines more efficiently in the vehicle drive device 100 equipped with two rotating electric machines that serve as a driving force source for the wheels W. A more specific configuration of the vehicle drive device 100 is illustrated below. FIG. 5 is a skeleton showing an example of the configuration of the vehicle drive device 100 illustrated in FIG. 1. Note that the directions of each component in the following description refer to the directions when the components are assembled in the vehicle drive device 100. Furthermore, terms related to the dimensions, arrangement direction, arrangement position, etc. of each component are concepts that include a state in which there is a difference due to an error (an error that is tolerable in manufacturing).

[0038] As shown in Fig. 5, the vehicle drive device 100 includes an input member IN drivingly connected to the internal combustion engine EG, an output member OUT drivingly connected to wheels W, a first rotating electric machine MG1 including a first rotor 10, a second rotating electric machine MG2 including a second rotor 20, and a plurality of gear mechanisms. As shown in Fig. 5, a pair of output members OUT are provided corresponding to the pair of wheels W. These are housed in a case (not shown). A part of the input member IN and a part of the output shaft OX connected to the pair of output members OUT are exposed to the outside of the case.

[0039] The vehicle drive device 100 includes three driving force transmission systems between the input member IN and the output member OUT. The first transmission system 1 is a transmission system that drive-connects the first rotor 10 and the output member OUT. The second transmission system 2 is a transmission system that drive-connects the second rotor 20 and the output member OUT. The third transmission system 3 is a transmission system that drive-connects the input member IN and the first rotor 10. The first transmission system 1, the second transmission system 2, and the third transmission system 3 may have a power transmission path that partially or entirely overlaps with the power transmission path of the other transmission systems. The first transmission system 1 includes a first engagement device CL1 that connects and disconnects the power transmission in the first transmission system 1, and the third transmission system 3 includes a second engagement device CL2 that connects and disconnects the power transmission in the third transmission system 3.

[0040] The vehicle drive device 100 also includes a first drive device 4A that drives the first engagement device CL1 and a second drive device 4B that drives the second engagement device CL2. The first drive device 4A includes a rotatably supported first shift drum 41 and a first cam mechanism 47 that converts the rotational motion of the first shift drum 41 into linear motion and transmits the linear motion to the first engagement device CL1. Similarly, the second drive device 4B includes a rotatably supported second shift drum 42 and a second cam mechanism 48 that converts the rotational motion of the second shift drum 42 into linear motion and transmits the linear motion to the second engagement device CL2. The first shift drum 41 and the second shift drum 42 are coaxially arranged and connected to each other via a drum drive shaft 49 so as to rotate together. The vehicle drive device 100 also includes a drum drive source 6 that drives the drum drive shaft 49.

[0041] In this embodiment, a configuration is illustrated in which the first drive device 4A and the second drive device 4B are configured as one common clutch drive device 4. In this embodiment, the first shift drum 41 and the second shift drum 42 are configured to share some of the components that constitute them. The first shift drum 41 and the second shift drum 42 rotate integrally via a single common drum drive shaft 49. The first shift drum 41 and the second shift drum 42 are collectively referred to simply as the shift drum 40.

[0042] As shown in FIG. 5, the first rotating electric machine MG1 and the first engagement device CL1 are disposed on the first axis A1. The second rotating electric machine MG2 is disposed on the second axis A2, which is a different axis parallel to the first axis A1. The output member OUT is disposed on the third axis A3, which is a different axis parallel to the first axis A1 and the second axis A2, together with an output differential gear mechanism DF, which will be described later. The input member IN and the second engagement device CL2 are disposed on the fourth axis A4, which is a different axis parallel to the first axis A1, the second axis A2, and the third axis A3. Here, in this specification, the direction along (parallel to) the first axis A1 (the second axis A2, the third axis A3, the fourth axis A4, and the fifth axis A5, which will be described later) is referred to as the "axial direction L" of the vehicle drive device 100, one side of which is referred to as the "axial first side L1" and the other side as the "axial second side L2". Here, the side to which the input member IN is connected to the internal combustion engine EG is referred to as the "axial second side L2". Additionally, the directions perpendicular to the first axis A1 to the fifth axis A5 are referred to as "radial directions" based on each axis. When it is not necessary to distinguish which axis is used as the reference or when it is clear which axis is used as the reference, the directions may simply be referred to as "radial directions." The above definitions of "axial direction L" and "radial directions" are also the same when there is another axis parallel to the first axis A1 to the fifth axis A5.

[0043] Although details will be described later, the vehicle drive device 100 includes at least a counter gear mechanism CG and an output differential gear mechanism DF as a plurality of gear mechanisms (a plurality of gears). In the vehicle drive device 100 shown in FIG. 5, the counter gear mechanism CG is disposed on a fifth axis A5 that is parallel to the first axis A1, the second axis A2, the third axis A3, and the fourth axis A4, and the output differential gear mechanism DF is disposed on the third axis A3. In addition to these, the vehicle drive device 100 includes an input gear 31, a first rotor gear 15, a second rotor gear 25, a first rotating electric machine output gear 19, a second rotating electric machine output gear 29, and a counter drive gear 35. Details of each mechanism and gear will be described later. Furthermore, the vehicle drive device 100 may be configured without having a counter gear mechanism CG and an output differential gear mechanism DF, and in which the input member IN and the first rotor 10 are drivingly connected, the first rotor 10 and the output member OUT are actively connected, and the second rotor 20 and the output member OUT are drivingly connected by a combination of multiple gears, etc.

[0044] The first rotating electric machine MG1 and the second rotating electric machine MG2 are inner rotor type rotating electric machines. The first rotating electric machine MG1 includes a first stator 12 and a first rotor 10. The first stator 12 is fixed to a non-rotating member (here, a case), and the first rotor 10 is rotatably arranged radially inside the first stator 12. A first rotor shaft 11 that rotates integrally with the first rotor 10 is arranged radially inside the first rotor 10. Similarly, the second rotating electric machine MG2 includes a second stator 22 and a second rotor 20. The second stator 22 is fixed to a non-rotating member (here, a case), and the second rotor 20 is rotatably arranged radially inside the second stator 22. A second rotor shaft 21 that rotates integrally with the second rotor 20 is arranged radially inside the second rotor 20.

[0045] As described above, in the third transmission system, the input member IN and the first rotor 10 are drivingly connected. In other words, the first rotor shaft 11, which rotates integrally with the first rotor 10, is drivingly connected to the input member IN. The input member IN is formed so as to extend along the axial direction L on the fourth axis A4. The input member IN is drivingly connected to the output shaft EOUT (crankshaft, etc.) of the internal combustion engine EG via a damper device DP that damps fluctuations in the transmitted torque.

[0046] An input gear 31 is disposed on the fourth shaft A4 to drive-connect the input member IN disposed on the fourth shaft A4 and the first rotor 10 disposed on the first shaft A1. A first rotor gear 15 that rotates integrally with the first rotor 10 is also connected to the first shaft A1. The input gear 31 disposed on the fourth shaft A4 is selectively connected to the input member IN via the second engagement device CL2. The input gear 31 and the first rotor gear 15 are engaged with each other, and when the input member IN and the input gear 31 are connected to each other via the second engagement device CL2, the power from the input member IN is transmitted to the first rotor 10. Therefore, the input gear 31, the second engagement device CL2, the first rotor gear 15, and the first rotor shaft 11 are included in a third transmission system 3 that drive-connects the input member IN and the first rotor 10.

[0047] When the second engagement device CL2 is in the disengaged state, the input gear 31 is not connected to the input member IN, and power from the internal combustion engine EG is not transmitted to the input gear 31. Therefore, driving force is not transmitted between the internal combustion engine EG and the first rotor 10.

[0048] Power is transmitted to the output member OUT via the output differential gear mechanism DF. The output differential gear mechanism DF distributes the rotation of the differential input gear 71 to the pair of output members OUT. In addition to the differential input gear 71, the output differential gear mechanism DF includes a pair of differential pinion gears supported by a differential case and a pair of side gears 73. Here, the pair of differential pinion gears and the pair of side gears 73 are all bevel gears. The differential case is a hollow member that rotates integrally with the differential input gear 71, and houses the pair of differential pinion gears and the pair of side gears 73 therein. In this embodiment, each of the pair of side gears 73 is a part of the output differential gear mechanism DF and also corresponds to the output member OUT.

[0049] The pair of differential pinion gears 72 are disposed so as to face each other with a gap therebetween along the radial direction based on the third axis A3. Each of the pair of differential pinion gears is attached to a pinion shaft supported so as to rotate integrally with the differential case, and can rotate (spin) about the pinion shaft and can rotate (revolve) about the third axis A3. The pair of side gears 73 are rotating elements after the distribution of the driving force in the output differential gear mechanism DF. The pair of side gears 73 are disposed so as to face each other with a gap therebetween in the axial direction L, sandwiching the pair of pinion shafts. Each of the side gears 73 is meshed with both of the differential pinion gears. Each of the pair of side gears 73 is connected to the pair of output shafts OX so as to rotate integrally with the pair of output shafts OX. Each of the pair of output shafts OX is drivingly connected to the wheels W. Each of the pair of output shafts OX may be considered as an output member OUT.

[0050] As described above, the second rotating electric machine MG2 is disposed on the second axis A2. In order to drive-connect the output member OUT disposed on the third axis A3 and the second rotor 20 disposed on the second axis A2, the second rotating electric machine output gear 29 is disposed on the second axis A2. The second rotating electric machine output gear 29 is connected to the second rotor shaft 21 that rotates integrally with the second rotor 20. The second rotating electric machine output gear 29 is drive-connected to the output differential gear mechanism DF via the counter gear mechanism CG disposed on the fifth axis A5. Therefore, the second rotor shaft 21, the second rotating electric machine output gear 29, the counter gear mechanism CG, and the output differential gear mechanism DF are included in the second transmission system 2 that drive-connects the second rotor 20 and the output member OUT.

[0051] The counter gear mechanism CG includes a first counter gear 61 and a second counter gear 62 that rotates integrally with the first counter gear 61. The second counter gear 62 is a gear with a smaller diameter than the first counter gear 61. In the counter gear mechanism CG, the rotation transmitted from the second rotating electric machine MG2 is reduced in speed and transmitted to the output differential gear mechanism DF. The first counter gear 61 is drivably connected to the first rotating electric machine output gear 19 disposed on the first shaft A1 via a counter drive gear 35 disposed on the fourth shaft A4. The first rotating electric machine output gear 19 is drivably connected to the first rotor shaft 11 via a first engagement device CL1. The counter gear mechanism CG drivably connects the output member OUT and the second rotor 20, as will be described in detail later. Therefore, the first rotor 10 to which the first rotor shaft 11 is connected is drivably connected to the output member OUT via the first engagement device CL1.

[0052] In an engaged state, the first engagement device CL1 connects the first rotor shaft 11 to the counter gear mechanism CG. By connecting the first rotor shaft 11 to the counter gear mechanism CG, the power from the internal combustion engine EG and the first rotating electric machine MG1 and the power from the second rotating electric machine MG2 can be transmitted to the output differential gear mechanism DF together. The power from the first rotor 10 is transmitted to the output member OUT via the first rotating electric machine output gear 19, the counter drive gear 35, the counter gear mechanism CG, and the output differential gear mechanism DF. Therefore, the first transmission system 1 that drive-connects the first rotor 10 to the output member OUT includes the first rotor shaft 11, the first engagement device CL1, the first rotating electric machine output gear 19, the counter drive gear 35, the counter gear mechanism CG, and the output differential gear mechanism DF.

[0053] The vehicle drive device 100 can be driven in a plurality of operation modes, for example, as illustrated in Table 1 below, depending on the operating states of the internal combustion engine EG, the first rotating electric machine MG1, the second rotating electric machine MG2, the second engagement device CL2, and the first engagement device CL1. In Table 1, "◯" in the columns for the second engagement device CL2 and the first engagement device CL1 indicates that the corresponding engagement devices are in an engaged state, and "◯" in the columns for the internal combustion engine EG, the first rotating electric machine MG1, and the second rotating electric machine MG2 indicates that the corresponding power source is in a state of outputting power. In addition, "●" in the column for the first rotating electric machine MG1 indicates that the power source is in a state of generating power by the transmitted power. "×" in the columns for the second engagement device CL2 and the first engagement device CL1 indicates that the corresponding engagement devices are in a released state. In addition, "×" in the columns for the internal combustion engine EG, the first rotating electric machine MG1, and the second rotating electric machine MG2 indicates that the corresponding power source is not outputting power, and the rotating electric machine is not generating power.

[0054] [Table 1]

[0055] For example, when sufficient power is stored in the DC power supply BAT and high driving force is not required, such as in the above-mentioned normal torque range G, the first EV mode is selected in which only the second rotating electric machine MG2 is driven as a power source. At this time, the internal combustion engine EG and the first rotating electric machine MG1 are stopped, and the second engagement device CL2 and the first engagement device CL1 are controlled to a disengaged state. The power of the second rotating electric machine MG2 is transmitted to the output differential gear mechanism DF via the second transmission system 2 to drive the wheels W. Note that the second engagement device CL2 may be in an engaged state.

[0056] When sufficient power is stored in the DC power supply BAT and a torque higher than that in the first EV mode is required, a second EV mode in which the first rotating electric machine MG1 and the second rotating electric machine MG2 are driven as a power source can be selected. At this time, the internal combustion engine EG is stopped, and the first rotating electric machine MG1 is driven together with the second rotating electric machine MG2. The second engagement device CL2 is controlled to a disengaged state, and the first engagement device CL1 is engaged to transmit the power of the first rotating electric machine MG1 to the output differential gear mechanism DF via the first transmission system 1, and transmit the power of the second rotating electric machine MG2 to the output differential gear mechanism DF via the second transmission system 2 to drive the wheels W.

[0057] In cases such as when the amount of electric power stored in the DC power supply BAT is insufficient, a series mode is selected in which the first rotating electric machine MG1 is caused to generate electric power by the power of the internal combustion engine EG and the second rotating electric machine MG2 is driven using the generated electric power. The internal combustion engine EG is driven, and the second engagement device CL2 is engaged, so that the power of the internal combustion engine EG is transmitted to the first rotating electric machine MG1 via the third transmission system 3, causing the first rotating electric machine MG1 to generate electric power. The first engagement device CL1 is controlled to a disengaged state, and the first transmission system 1 is interrupted, so that the power of the internal combustion engine EG and the first rotating electric machine MG1 is not transmitted to the output differential gear mechanism DF. On the other hand, the power of the second rotating electric machine MG2 is transmitted to the output differential gear mechanism DF and the wheels W via the second transmission system 2.

[0058] When a torque higher than that in the series mode (or the first EV mode) is required, a so-called parallel mode can be selected in which the power of the internal combustion engine EG is also transmitted to the output differential gear mechanism DF in addition to the power of the second rotating electric machine MG2 to drive the wheels W. The internal combustion engine EG is driven, and the second engagement device CL2 is engaged, so that the power of the internal combustion engine EG is transmitted to the first rotating electric machine MG1 via the third transmission system 3, causing the first rotating electric machine MG1 to generate electricity. Furthermore, the first engagement device CL1 is engaged, so that the power from the internal combustion engine EG can be transmitted to the output differential gear mechanism DF via the first transmission system 1. The power from the internal combustion engine EG is transmitted to the output differential gear mechanism DF via the first transmission system 1, and the power of the second rotating electric machine MG2 is transmitted to the output differential gear mechanism DF via the second transmission system 2 to drive the wheels W.

[0059] In the above-mentioned state in the parallel mode, the second rotating electric machine MG2 is powered ("○" in the table), and the first rotating electric machine MG1 is generating electricity ("●" in the table). However, the first rotating electric machine MG1 does not have to be powered or generate electricity (regeneratively) ("×" in the table). Also, in this mode, the first rotating electric machine MG1 may be controlled to output driving force (powered) according to the amount of electric power stored in the DC power supply BAT and the required driving force ("○" in the table). At this time, the second rotating electric machine MG2 may be powered ("○" in the table) or may be stopped ("×" in the table). When the second rotating electric machine MG2 is powered, the power of the internal combustion engine EG, the first rotating electric machine MG1, and the second rotating electric machine MG2 is transmitted to the output differential gear mechanism DF to drive the wheels W. When the second rotating electric machine MG2 is stopped, the power of the internal combustion engine EG and the first rotating electric machine MG1 is transmitted to the output differential gear mechanism DF to drive the wheels W.

[0060] In addition, by stopping the second rotating electric machine MG2 and disengaging the first engagement device CL1 so that no power is transmitted to the output differential gear mechanism DF, engaging the second engagement device CL2 and driving the internal combustion engine EG to cause the first rotating electric machine MG1 to generate power using the power, a charging mode can be realized in which the DC power source BAT is charged while the vehicle is stopped.

[0061] In this embodiment, the first engagement device CL1 and the second engagement device CL2 are meshing type engagement devices (dog clutches). The first engagement device CL1 is configured to be able to switch between an engaged state and a released state by the first drive device 4A, and the second engagement device CL2 is configured to be able to switch between an engaged state and a released state by the second drive device 4B. Specifically, the first engagement device CL1 has a first meshing member DS1 (dog sleeve) configured to move along the axial direction L by the first drive device 4A, and a pair of first meshed members DT1 with which the first meshing member DS1 is engaged. The second engagement device CL2 has a second meshing member DS2 (dog sleeve) configured to move along the axial direction L by the second drive device 4B, and a pair of second meshed members DT2 with which the second meshing member DS2 is engaged.

[0062] The first engagement device CL1 switches between an engaged state and a released state depending on the position of the first meshing member DS1 in the axial direction L, and the second engagement device CL2 switches between an engaged state and a released state depending on the position of the second meshing member DS2 in the axial direction L. Here, one of the pair of first meshed members DT1 is connected to the first rotor shaft 11 so as to rotate integrally therewith, and the other is connected to the first rotating electric machine output gear 19 so as to rotate integrally therewith. Also, one of the pair of second meshed members DT2 is connected to the input member IN so as to rotate integrally therewith, and the other is connected to the input gear 31 so as to rotate integrally therewith.

[0063] The first engagement device CL1 is in an engaged state when the first meshing member DS1 engages with both of the pair of first meshed members DT1, and in a released state when the first meshing member DS1 separates from at least one of the pair of first meshed members DT1. The second engagement device CL2 is in an engaged state when the second meshing member DS2 engages with both of the pair of second meshed members DT2, and in a released state when the second meshing member DS2 separates from at least one of the pair of second meshing members DS2.

[0064] The first shift drum 41, the second shift drum 42, and the drum drive shaft 49 are disposed on a drum rotation axis A0, which is a separate axis parallel to the fourth axis A4 to the fifth axis A5, and rotate around the drum rotation axis A0. The second shift drum 42 and the first shift drum 41 are formed in a cylindrical shape centered on the drum rotation axis A0. The drum drive shaft 49 is a shaft member that connects the second shift drum 42 and the first shift drum 41 so that they rotate integrally, and is formed to extend along the drum rotation axis A0. As the drum drive source 6, various motors can be adopted, and for example, an AC rotating electric machine driven by a multi-phase AC power can be adopted. More specifically, as the drum drive source 6, a servo motor or a stepping motor is preferably used.

[0065] As shown in Fig. 5, the drum drive shaft 49 and the drum drive source 6 are connected via a reduction gear 5. The reduction gear 5 includes a first reduction gear 51 and a second reduction gear 52 having a larger diameter than the first reduction gear 51. The first reduction gear 51 is disposed on a separate axis parallel to the drum rotation axis A0 and is connected to the rotation axis of the drum drive source 6. The second reduction gear 52 meshes with the first reduction gear 51, is disposed on the drum rotation axis A0, and is connected to the drum drive shaft 49. The drum drive source 6 needs a large driving force to drive two drums, but by providing such a reduction gear 5, the drum drive source 6 can be easily made smaller in size.

[0066] As shown in FIG. 5, the first cam mechanism 47 includes a first cam guideway 43 and a first cam follower 45, and the second cam mechanism 48 includes a second cam guideway 44 and a second cam follower 46. The first cam guideway 43 is provided along the rotation direction of the first shift drum 41, and the second cam guideway 44 is provided along the rotation direction of the second shift drum 42. In this embodiment, the first cam guideway 43 is configured by a groove portion continuously formed along the circumferential direction on the outer circumferential surface of the first shift drum 41, and the second cam guideway 44 is configured as a groove continuously formed along the circumferential direction on the outer circumferential surface of the second shift drum 42. The first cam guideway 43 is formed so that the phase changes according to the rotation of the first shift drum 41, and the second cam guideway 44 is formed so that the phase changes according to the rotation of the second shift drum 42.

[0067] Here, the "phase" of the first cam guideway 43 and the second cam guideway 44 refers to the respective positions of the first cam guideway 43 and the second cam guideway 44 in a direction along the rotation axis of the shift drum 40 (here, the axial direction L). The first cam follower 45 performs linear motion in response to a change in the phase of the first cam guideway 43, and the second cam follower 46 performs linear motion in response to a change in the phase of the second cam guideway 44. The first cam follower 45 and the second cam follower 46 are formed so as to extend along a specific radial direction, and are arranged so that a part of each of them is located within the grooves of the first cam guideway 43 and the second cam guideway 44. The shape of these cam guideways is not limited to a groove shape, and may be formed, for example, in a convex shape formed continuously along the circumferential direction on the outer circumferential surface of the shift drum 40, or the guideway may be formed on the end face or inner circumferential surface of the shift drum 40 in the axial direction L.

[0068] The first cam follower 45 and the second cam follower 46 perform linear motion along the axial direction L according to the phase of the respective cam guideways, thereby driving the first engagement device CL1 and the second engagement device CL2, respectively. The first cam follower 45 and the second cam follower 46 are connected to a shift fork (not shown), and are connected to the first meshing member DS1 and the second meshing member DS2 (dog sleeve) via the shift fork, respectively. The first cam follower 45 and the second cam follower 46 perform linear motion along the axial direction L, thereby switching the engagement states of the first engagement device CL1 and the second engagement device CL2, respectively.

[0069] As described above, the first cam mechanism 47 and the second cam mechanism 48 switch the engagement state of the second engagement device CL2 and the first engagement device CL1 in response to the rotation of the drum drive shaft 49. Specifically, as shown in FIG. 6, the first cam mechanism 47 and the second cam mechanism 48 transition to four operation modes, namely, a first mode (MODE1), a second mode (MODE2), a third mode (MODE3), and a fourth mode (MODE4), in response to the rotation toward the first rotation direction side D1, which is one side of the rotation direction D around the drum drive shaft 49. The state transition diagram of FIG. 6 shows the relationship between the engagement state of the first engagement device CL1 and the second engagement device CL2 and the operation mode of the vehicle drive device 100, using a development view of the first cam guideway 43 and the second cam guideway 44 formed along the circumferential direction (rotation direction) of the cylindrically formed first shift drum 41 and second shift drum 42.

[0070] The first mode is an operation mode in which the second engagement device CL2 is in a disengaged state and the first engagement device CL1 is in an engaged state. In this operation mode, as described above with reference to Table 1, it is possible to realize a so-called two-motor EV mode (second EV mode) in which the transmission of driving force between the internal combustion engine EG and the output member OUT is interrupted and the driving forces of both the first rotating electric machine MG1 and the second rotating electric machine MG2 are transmitted to the output member.

[0071] The second mode is an operation mode in which the second engagement device CL2 is in a disengaged state and the first engagement device CL1 is in a disengaged state. In this operation mode, as described above with reference to Table 1, a so-called one-motor EV mode (first EV mode) can be realized in which the transmission of driving force between the internal combustion engine EG and the first rotating electric machine MG1 and the output member OUT is interrupted and the driving force of the second rotating electric machine MG2 is transmitted to the output member OUT.

[0072] The third mode is an operation mode in which the second engagement device CL2 is in an engaged state and the first engagement device CL1 is in a disengaged state. In this operation mode, as described above with reference to Table 1, a so-called series mode can be realized in which the driving force of the internal combustion engine EG is transmitted to the first rotating electric machine MG1 to cause the first rotating electric machine MG1 to generate electricity while the driving force of the second rotating electric machine MG2 is transmitted to the output member OUT while the transmission of driving force between the internal combustion engine EG and the first rotating electric machine MG1 and the output member OUT is interrupted.

[0073] The fourth mode is an operation mode in which the second engagement device CL2 is in an engaged state and the first engagement device CL1 is in an engaged state. In this operation mode, as described above with reference to Table 1, a so-called parallel mode in which the driving forces of the internal combustion engine, the first rotating electric machine, and the second rotating electric machine are transmitted to the output member can be realized.

[0074] The first cam mechanism 47 and the second cam mechanism 48 change states in the order of the first mode, the second mode, the third mode, and the fourth mode in response to rotation toward the first side D1 in the rotation direction. Also, the first cam mechanism 47 and the second cam mechanism 48 change states in the order of the fourth mode, the third mode, the second mode, and the first mode in response to rotation toward the second side D2 in the rotation direction.

[0075] For example, when the second mode is selected when the vehicle starts and the vehicle runs in one-motor EV mode (first EV mode), in the normal torque range G as described above with reference to Figure 4, the vehicle can continue running in the first EV mode without changing modes.

[0076] Here, when the SOC decreases, by transitioning to the third mode, the internal combustion engine EG can be started by the driving force of the first rotating electric machine MG1 while the power transmission between the first rotating electric machine MG1 and the internal combustion engine EG (input member IN) and the output member OUT is interrupted. In other words, the internal combustion engine EG can be started without a starter actuator for the internal combustion engine EG, such as a starter motor. After the internal combustion engine EG starts, a series mode can be realized in which the driving force of the internal combustion engine EG is used to cause the first rotating electric machine MG1 to generate electricity, and the electric power is used to drive the second rotating electric machine MG2.

[0077] When the state transition occurs from traveling in the first EV mode to the parallel mode (transition from the third operating point Q3 to the fourth operating point Q4 in FIG. 2), the internal combustion engine EG is started as described above by transitioning from the second mode to the third mode, and the series mode is realized. Then, the parallel mode can be realized by further transitioning from the third mode to the fourth mode. At this time, in the third mode, only the starting of the internal combustion engine EG is performed, and the parallel mode may be realized by transitioning to the fourth mode without actually executing the series mode.

[0078] Furthermore, when the state transition occurs from traveling in the first EV mode to traveling in the second EV mode (transition from the first operating point Q1 to the second operating point Q2 in FIG. 2), the vehicle transitions from the second mode to the first mode. In the first mode, as described above with reference to Table 1, a so-called two-motor EV mode (second EV mode) is realized in which the transmission of driving force between the internal combustion engine EG and the output member OUT is interrupted and the driving forces of both the first rotating electric machine MG1 and the second rotating electric machine MG2 are transmitted to the output member.

[0079] When the state transition is made from the second EV mode to any of the hybrid modes, the transmission of driving force between the first rotating electric machine MG1 and the second rotating electric machine MG2 is first interrupted, and the internal combustion engine EG is started in a state in which driving force is transmitted between the internal combustion engine EG and the first rotating electric machine MG1. That is, the state transition is made from the first mode through the second mode to the third mode. Then, after the start of the internal combustion engine EG, if the third mode is maintained, the series mode can be realized, and if the state transition is made to the fourth mode, the parallel mode can be realized.

[0080] As described above, in the vehicle driving device 100 of this embodiment, the vehicle can travel in the first EV mode in all speed ranges required for the vehicle. Therefore, it is easy to improve the energy efficiency of the vehicle driving device 100 as a whole. Furthermore, in a hybrid driving device such as the second vehicle driving device 100B in which two engagement devices are linked via a common shift drum 40 to effect a state transition, a smooth state transition can be made from the first EV mode, which is performed in all speed ranges, to other operation modes (second EV mode, series mode, parallel mode).

[0081] In this way, the vehicle drive device 100 can execute one motor EV mode (first EV mode), two motor EV mode (second EV mode), and parallel mode as drive methods for the wheels W. The one motor EV mode is a driving mode that is also used for measuring fuel efficiency of the vehicle and is sometimes called a "mode driving mode". The two motor EV mode is sometimes called a "general driving mode". And the parallel mode is sometimes called a "maximum output mode". As described above, the maximum vehicle speed in the one motor EV mode, the two motor EV mode, and the parallel mode is the same at the second speed V2. That is, the vehicle drive device 100 is configured to be able to handle the maximum vehicle speed in cases where only the second rotating electric machine MG2 is used as a driving force source, where the first rotating electric machine MG1 and the second rotating electric machine MG2 are used as driving force sources, or where the first rotating electric machine MG1, the second rotating electric machine MG2, and the internal combustion engine EG are used as driving force sources.

[0082] In order to handle the maximum vehicle speed in the one-motor EV mode (first EV mode) as the mode driving mode, it is necessary to set the gear ratio from the second rotor shaft 21 to the output member OUT so that the maximum rotation speed of the second rotating electric machine MG2 is equal to or higher than the rotation speed of the wheels W (= the rotation speed of the output member OUT). In this embodiment, the gear ratio (the gear ratio of the multiple gears of the second transmission system 2) from the second rotating electric machine output gear 29 integrally connected to the second rotor shaft 21 to the input to the differential input gear 71 via the counter gear mechanism CG is set in this manner. For example, when the maximum rotation speed of the wheels W is 10,000 [rpm] and the maximum rotation speed of the second rotating electric machine MG2 is 5,000 [rpm], the gear ratio is set to "2".

[0083] In the two-motor EV mode (second EV mode) serving as the general driving mode, both the first rotating electric machine MG1 and the second rotating electric machine MG2 need to correspond to the maximum rotation speed of the wheels W. That is, the gear ratio (the gear ratio of the multiple gears of the second transmission system 2) from the second rotating electric machine output gear 29 integrally connected to the second rotor shaft 21 to the differential input gear 71 via the counter gear mechanism CG, and the gear ratio (the gear ratio of the multiple gears of the first transmission system 1) from the first rotating electric machine output gear 19 drivingly connected to the first rotor shaft 11 via the first engagement device CL1 to the differential input gear 71 via the counter drive gear 35 and the counter gear mechanism CG are set so that the maximum rotation speeds of both the first rotating electric machine MG1 and the second rotating electric machine MG2 are equal to or higher than the maximum rotation speed of the wheels W. A part of the gear mechanism in the first transmission system 1 is also used by the second transmission system 2, so that the gear ratio of the first transmission system 1 can be set by setting the gear ratio of the second transmission system 2.

[0084] In the parallel mode as the maximum output mode, the first rotating electric machine MG1, the second rotating electric machine MG2, and the input member IN (internal combustion engine EG) all need to correspond to the maximum rotation speed of the wheels W. That is, the gear ratio of the second transmission system 2, the gear ratio of the first transmission system 1, and the gear ratio from the input member IN through the second engagement device CL2, the input gear 31, the first rotor gear 15, the first engagement device CL1, the first rotating electric machine output gear 19, the counter drive gear 35, and the counter gear mechanism CG to the differential input gear 71 (the gear ratios of the third transmission system 3 and the first transmission system 1) are set so that the maximum rotation speeds of the first rotating electric machine MG1, the second rotating electric machine MG2, and the input member IN (internal combustion engine EG) are all equal to or higher than the maximum rotation speed of the wheels W. Since a part of the gear mechanism in the transmission system from the input member IN to the differential input gear 71 is shared by the first transmission system 1 and the second transmission system 2, the gear ratio of the multiple gears in the third transmission system 3 can be set by setting the gear ratio of the first transmission system 1 and the second transmission system 2. Thus, the total gear ratio of the first transmission system 1, the second transmission system 2, and the third transmission system 3 can be set.

[0085] That is, the vehicle drive device 100 includes a first transmission system 1 including a plurality of gears including a counter gear mechanism CG and drivingly connecting the first rotor 10 and the output member OUT, a second transmission system 2 including a plurality of gears including the counter gear mechanism CG and drivingly connecting the second rotor 20 and the output member OUT, and a third transmission system 3 including a plurality of gears and drivingly connecting the input member IN and the first rotor 10. The gear ratio of the first transmission system 1 is set to a gear ratio that allows the maximum speed of the output member OUT to be outputted by the maximum rotation speed of the first rotating electric machine MG1. The gear ratio of the second transmission system 2 is set to a gear ratio that allows the maximum speed of the output member OUT to be outputted by the maximum rotation speed of the second rotating electric machine MG2. The gear ratio of the third transmission system 3 and the first transmission system 1 combined is set to a gear ratio that allows the maximum speed of the output member OUT to be outputted by the maximum rotation speed of the internal combustion engine EG.

[0086] In this specification, a specific structure of the vehicle drive device 100 has been described with reference to Figures 5 and 6, but the configuration of the vehicle drive device 100 is not limited to this example. The configuration of the vehicle drive device 100 may be in another form as long as it includes the transmission system as described above with reference to Figure 1. [Explanation of symbols]

[0087] 1: first transmission system, 2: second transmission system, 3: third transmission system, 10: first rotor, 20: second rotor, 100: vehicle drive device, A1: first shaft, A2: second shaft, A3: third shaft, A4: fourth shaft, A5: fifth shaft, CG: counter gear mechanism, CL1: first engagement device, CL2: second engagement device, CTL: control device, EG: internal combustion engine, F1: first region, F2: second region, F3: third region, IN: input member, MG1: first rotating electric machine, MG2: second rotating electric machine, OUT: output member, S1: low vehicle speed range, S2: medium vehicle speed range, S3: high vehicle speed range, W: wheel

Claims

1. An output member drivingly connected to the wheels; a first rotating electric machine including a first rotor; a second rotating electric machine including a second rotor; an input member drivingly connected to the internal combustion engine; a first transmission system that drivingly connects the first rotor and the output member; a second transmission system that drivingly connects the second rotor and the output member; a third transmission system that drivingly connects the input member and the first rotor; a first engagement device that connects and disconnects power transmission in the first transmission system; a second engagement device that connects and disconnects power transmission in the third transmission system; a control device that controls the first rotating electric machine, the second rotating electric machine, the first engagement device, and the second engagement device, a mode in which the first engagement device and the second engagement device are in a disengaged state and a driving force of the second rotating electric machine is transmitted to the output member is defined as a first EV mode; a mode in which the first engagement device is in an engaged state and the second engagement device is in a released state, and driving forces of the first rotating electric machine and the second rotating electric machine are transmitted to the output member, the mode being a second EV mode; a mode in which the first engagement device and the second engagement device are in an engaged state and driving forces of the internal combustion engine, the first rotating electric machine, and the second rotating electric machine are transmitted to the output member is defined as a parallel mode; The control device is capable of executing the first EV mode, the second EV mode, and the parallel mode, In the vehicle operation range defined by the vehicle speed and the driving force, a low vehicle speed range is set on the lowest vehicle speed side, a high vehicle speed range is set on the highest vehicle speed side, and a medium vehicle speed range is set between them, In the low vehicle speed region, the first EV mode is executed in a first region where the driving force is relatively low, and the second EV mode is executed in a second region where the driving force is relatively high. In the medium vehicle speed region, the first EV mode is executed in the first region, the second EV mode is executed in the second region, and the parallel mode is executed in a third region in which a driving force is higher than that in the second region, a vehicle drive device, wherein in the high vehicle speed region, the first EV mode is executed in the first region and the second EV mode is executed in the second region, and the parallel mode is executable in all regions including the third region regardless of driving force.

2. a maximum vehicle speed at which the first EV mode is executed, a maximum vehicle speed at which the second EV mode is executed, and a maximum vehicle speed at which the parallel mode is executed are the same; At each vehicle speed included in a vehicle speed range in which both the first EV mode and the second EV mode are executed, a maximum torque of the first EV mode is smaller than a maximum torque of the second EV mode, The driving force required to be transmitted to the output member is defined as a required driving force, 2. The vehicle drive device according to claim 1, wherein the control device executes the second EV mode when the required driving force becomes higher than a maximum torque of the first EV mode at each vehicle speed, and executes the parallel mode when the required driving force becomes higher than a maximum torque of the second EV mode at each vehicle speed.

3. a series mode in which the first engagement device is in a disengaged state and the second engagement device is in an engaged state, the first rotating electric machine generates electricity using the driving force of the internal combustion engine, and the driving force of the second rotating electric machine is transmitted to the output member; The vehicle drive system according to claim 1 or 2, wherein the control device is further capable of executing the series mode.

4. The vehicle drive device according to claim 1 , wherein the first rotating electric machine and the second rotating electric machine are rotating electric machines having the same maximum torque and maximum rotation speed.

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