JP6507726B2 - Power transmission - Google Patents

Description

  The present invention relates to a power transmission device.

  For example, as described in Patent Document 1, there are conventionally vehicles in which front wheels are driven by an engine and rear wheels are driven by a motor. The control device of the vehicle applies the required motor torque to the rear wheels by controlling the motor according to the traveling state of the vehicle and the like. In addition, the motor functions as a generator under conditions such as deceleration of the vehicle. The rotational resistance at the time of power generation in this motor is used as a braking force. Further, the electric power as the regenerated energy to be generated is supplied to a storage battery of the vehicle and used for charging thereof.

JP, 2014-69657, A

  However, in vehicles including regenerative power generation using a motor that is one of the driving power sources, including the vehicle described in Patent Document 1, there are concerns as follows. For example, when the vehicle decelerates, the motor rotates in conjunction with the rear wheels, so it is difficult to control the amount of power generated by the motor. Because the capacity of the storage battery is limited, it may soon reach a fully charged state. And after this, when the electric power generated by the motor is supplied to the storage battery, the storage battery may be overcharged and its deterioration may be promoted.

  An object of the present invention is to provide a power transmission system capable of performing more appropriate regenerative power generation.

  A power transmission device capable of achieving the above object is the auxiliary drive of a four-wheel drive vehicle having left and right main drive wheels to which power is always transmitted, and left and right auxiliary drive wheels to which power is transmitted according to traveling conditions. It transmits power to the wheels.

  Then, the power transmission device generates power to be transmitted to the auxiliary drive wheel by consuming and rotating power supplied from a storage battery mounted on the vehicle, while the auxiliary drive wheel is supplied with power being stopped. The power transmission ratio between the motor and the auxiliary drive wheel is continuously changed between 0% and 100% through a motor that generates electric power regenerated by the storage battery by rotating in an interlocking manner, and through electronic control. And a controller for controlling the motor and the coupling, respectively.

  The control device stops the power supply to the motor and sets the power transmission ratio to a value larger than 0% when the remaining amount of the storage battery falls below a predetermined threshold while the vehicle is traveling. By setting, the power generation by the motor is started, and when the remaining amount of the storage battery recovers beyond a predetermined threshold, the power transmission ratio is set to 0% to end the power generation by the motor. Do.

  According to this configuration, during traveling of the vehicle, when the remaining amount of the storage battery falls below a predetermined threshold value, power generation by the motor is started. When power supply to the motor is stopped, the rotational force of the auxiliary drive wheel is transmitted to the motor according to the power transmission ratio of the coupling. The motor generates electric power by rotating according to the transmitted rotational force. On the other hand, when the remaining amount of the storage battery recovers beyond a predetermined threshold value, the power generation by the motor is ended. As described above, more appropriate regenerative power generation is performed according to the remaining amount of the storage battery, thereby suppressing the generation of the surplus power by the motor and the overcharging of the storage battery.

In the above power transmission device, it is preferable that the power transmission ratio set when power generation by the motor is started is set to a different value in accordance with the traveling state of the vehicle.
Here, as the rotational force transmitted to the motor via the coupling is larger, the amount of power generation of the motor increases. At this time, not only the power generation amount but also the regenerative braking force by the motor increases. Therefore, depending on the traveling state of the vehicle, the driver may feel a slight impact due to the regenerative braking force by the motor. In this respect, as described above, the value of the power transmission ratio of the coupling, which is set when starting the regenerative power generation by the motor, is made different according to the traveling state of the vehicle, thereby responding to the traveling state of the vehicle More appropriate regenerative power generation is performed. Further, since it is possible to generate a more appropriate regenerative braking force according to the traveling state of the vehicle, the ride comfort of the vehicle is also secured.

  In the above power transmission device, when setting the power transmission ratio when starting power generation by the motor, the control device gradually changes from the power transmission ratio before the setting to the power transmission ratio after the setting. Is preferred.

  In this way, it is possible to reduce the impact that accompanies a sudden change in the power transmission rate of the coupling. The larger the difference between the power transmission rate of the coupling before change and the target power transmission rate, the more effective.

  In the above-described power transmission device, the control device can detect the traveling state in which four-wheel drive is required even if the remaining amount of the storage battery is reduced to a predetermined threshold value or less. Preferably, the left and right auxiliary drive wheels are driven through control of

As described above, by giving priority to traveling by four-wheel drive to charging of the storage battery, traveling stability of the vehicle can be continuously ensured.
In the above power transmission device, the control device may detect a traveling state in which four-wheel drive is required based on at least one of front and rear wheel speed differences and left and right wheel speed differences.

  It is possible to detect front or rear wheel slip based on front and rear wheel speed differences. In addition, it is possible to detect curve travel of the vehicle based on the difference between the wheel speeds on the left and right. From the viewpoint of securing traveling stability, when slip occurs or traveling on a curved road, traveling by four-wheel drive is preferable.

  The above power transmission device may have a differential mechanism that distributes the power of the motor to the left and right auxiliary drive wheels. In this case, the coupling is preferably provided between the motor and the differential mechanism. Only one coupling may be provided.

  In the above power transmission device, the motor may include first and second motors. In this case, it is preferable that the first and second motors be connected to the left and right auxiliary drive wheels respectively through the couplings.

  According to this configuration, the left and right auxiliary drive wheels are independently driven by the two motors. In this case, it is possible to freely change the power transmission ratio between the two motors and the left and right auxiliary drive wheels by respectively providing couplings between the two motors and the left and right auxiliary drive wheels. Become.

  In the above power transmission device, the traveling state of the vehicle is at least one of a first traveling state traveling at a constant speed, a second traveling state inertially traveling on a downward slope, and a third traveling state decelerated by a brake. May be included. In this case, the control device performs the first traveling state based on the vehicle speed, the second traveling state based on the vehicle speed and the operation state of the accelerator, and the third traveling state based on the vehicle speed and the operation state of the brake. Each may be determined.

  By changing the power transmission ratio of the coupling according to at least one of the first to third traveling states, it is possible to secure the ride comfort of the vehicle in the first to third traveling states. This is because the magnitude of the preferable regenerative braking force differs depending on the traveling state of the vehicle. For example, when the vehicle is traveling steadily, it is preferable to suppress the power transmission ratio of the coupling because it is desirable to suppress the impact accompanying the change of the power transmission ratio of the coupling as much as possible. On the other hand, when the vehicle is decelerated by the brake operation, since the driver's intention to decelerate is clear, the power transmission ratio of the coupling and hence the regenerative braking force may be increased.

  According to the power transmission device of the present invention, more appropriate regenerative power generation can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows schematic structure of the vehicle by which the power transmission device in 1st Embodiment is mounted. 6 is a flowchart showing a control procedure of coupling in the first embodiment. The flowchart which shows the control procedure of the coupling in 2nd Embodiment. The block diagram which shows an example of the power transmission device in 3rd Embodiment.

First Embodiment
Hereinafter, a first embodiment in which the power transmission device is embodied in a four-wheel drive vehicle will be described.
As shown in FIG. 1, a vehicle 11 includes an internal combustion engine (engine) 12 which is a main drive source for traveling. The driving force of the internal combustion engine 12 is transmitted to the left and right front wheels 16, 16 via the transmission 13, the front differential gear 14 and the left and right front drive shafts 15, 15. When the vehicle 11 travels (forward and reverse), the driving force generated by the internal combustion engine 12 is always transmitted to the left and right front wheels 16 and 16.

  In addition, the vehicle 11 includes a storage battery (BAT) 21 and a power transmission device 22. The power transmission device 22 has a motor 23 as an auxiliary drive source for traveling, an electronic control coupling 24, a rear differential gear 25 and an ECU (electronic control unit) 26.

  The driving force (torque) of the motor 23 is transmitted to the left and right rear wheels 28, 28 via the output shaft 23s, the electronic control coupling 24, the rear differential gear 25, and the left and right rear drive shafts 27, 27. .

  As the motor 23, for example, a shunt DC machine is employed. A shunt wound DC machine is one in which an armature winding and a field winding are connected in parallel with each other. The motor 23 functions as a generator (other excitation generator) when the vehicle 11 is decelerating traveling or inertial traveling. The separately-excited generator refers to one that uses another power supply instead of its own electromotive force as a power supply of a field winding that generates a magnetic field. Here, the field current supplied to the motor 23 is maintained constant.

  Electronic control coupling 24 transmits the driving force of motor 23 to rear differential gear 25. Electronic control coupling 24 has its transmission torque (power transmission ratio) continuously changed between 0% and 100% through electronic control by ECU 26. Although not shown, the electronic control coupling 24 has a main clutch (multi-plate friction clutch), a pilot clutch (electromagnetic multi-plate clutch), a cam mechanism and an electromagnet. The pilot clutch is engaged by the electromagnetic force of the electromagnet, and the engagement force (frictional torque) is transmitted to the main clutch via the cam mechanism, whereby the main clutch is engaged. By controlling the current supplied to the electromagnet, it is possible to control the transmission torque of the electronic control coupling 24.

  The storage battery 21 is an operation power supply of the motor 23, various electric components including the electronic control coupling 24, and various computer devices including the ECU 26. Moreover, the storage battery 21 stores the electric power generated by the motor 23 functioning as a generator.

  The ECU 26 acquires detection results of various sensors provided in the vehicle 11 as vehicle information indicating a traveling state of the vehicle 11 or a driver's request, and the motor 23 and the electronic control coupling 24 according to the acquired vehicle information. Control each one. The sensors include a wheel speed sensor 31, a vehicle speed sensor 32, an accelerator pedal sensor 33, and a brake pedal sensor 34 provided on each wheel. The ECU 26 detects the rotational speed (wheel speed) Vw of each wheel, the vehicle speed V which is the traveling speed of the vehicle 11, the depression amount Pa of the accelerator pedal, and the depression amount Pb of the brake pedal as vehicle information through these sensors.

  The ECU 26 maintains the transmission torque of the electronic control coupling 24 at 100% when the vehicle 11 is in the normal traveling state (forward travel, reverse travel). Then, the ECU 26 controls the rotation of the motor 23 according to the traveling state of the vehicle 11 to control the driving force transmitted to the rear wheels 28, 28 (normal four-wheel drive control). Unlike the internal combustion engine 12, when the vehicle 11 travels (forwards or reverses), the driving force generated by the motor 23 is additionally transmitted to the left and right rear wheels 28, 28.

  The ECU 26 constantly monitors the voltage of the storage battery 21 through the voltage sensor 35 provided in the storage battery 21 and detects the charge amount (remaining amount) of the storage battery 21 based on the voltage. The ECU 26 stops the power supply to the motor 23 as control for performing regenerative power generation by the motor 23 when the charge amount of the storage battery 21 decreases. At this time, the ECU 26 sets the transmission torque of the electronic control coupling 24 in accordance with the traveling state of the vehicle 11 at that time. Through control of the transmission torque, it is possible to control the amount of power generation of the motor 23 and hence the regenerative braking force.

<Processing procedure of power transmission control>
Next, the procedure of power transmission control for the rear wheels will be described. The process is executed by the ECU 26. The vehicle 11 is traveling, and the ECU 26 executes normal four-wheel drive control.

As shown in the flowchart of FIG. 2, the ECU 26 takes in the voltage of the storage battery 21 through the voltage sensor 35 (step S101).
Next, the ECU 26 determines, based on the voltage of the storage battery 21, whether the remaining amount of the storage battery 21 has decreased, that is, whether the storage battery 21 needs to be charged (step S102).

Specifically, the ECU 26 determines whether the following condition (A) is satisfied.
· Charge amount (remaining amount) of storage battery 21> threshold value X (%) ... (A)
Since there is a correlation between the voltage of the storage battery 21 and the charge amount, it is possible to estimate the charge amount based on the voltage. Threshold value X for determining the charge amount is set, for example, based on the charge amount of storage battery 21 at the time of full charge. In addition, you may perform necessity determination of charge through comparison with the voltage of the storage battery 21, and a threshold value.

  The ECU 26 executes four-wheel drive control when it is determined that charging of the storage battery 21 is not necessary, that is, when it is determined that the charging amount of the storage battery 21 exceeds the threshold X (NO in step S102). (Step S103), and the process ends.

  When it is determined that the storage battery 21 needs to be charged, that is, when it is determined that the charge amount of the storage battery 21 does not exceed the threshold value X (YES in step S102), the ECU 26 proceeds to step S104. Transition.

  In step S104, the ECU 26 determines whether it is necessary to drive four wheels. Specifically, the ECU 26 determines whether at least one of the following two conditions (B1) and (B2) is satisfied.

・ Front and rear wheel speed difference> Threshold value Vw1 (B1)
· Left and right wheel speed difference> threshold value Vw2 ... (B2)
The condition (B1) is for determining a slip. When the front and rear wheel speed difference is larger than the threshold value Vw1, it is determined that the vehicle 11 is slipping. The condition (B2) is for determining a curve travel. When the left and right wheel speed difference is larger than the threshold value Vw2, it is determined that the vehicle 11 is traveling on a curved road.

  When it is determined that the ECU 26 needs to drive the four wheels, specifically, when it is determined that at least one of the two conditions (B1) and (B2) is satisfied (YES in step S104), Then, the process proceeds to step S103 to execute or continue four-wheel drive control.

  That is, even if the charge amount (voltage) of the storage battery 21 is lowered to the threshold value X or less, four-wheel drive performance such as when a slip occurs or while traveling on a curved road is required. Under the circumstances, securing the traveling stability of the vehicle 11 is given priority over the charging of the storage battery 21.

  When it is determined that the ECU 26 does not need to drive the four wheels, specifically, when it is determined that neither of the two conditional expressions (B1) and (B2) holds (NO in step S104), The wheel drive control is canceled (step S105). That is, the ECU 26 stops the power supply to the motor 23 to charge the storage battery 21. When the motor 23 is stopped, the vehicle 11 is in the front wheel drive state.

  Thereafter, the ECU 26 controls the transmission torque of the electronic control coupling 24 according to the traveling state of the vehicle 11. This is because regenerative power generation (charging of the storage battery 21) according to the traveling state of the vehicle 11 is performed. Specifically, the ECU 26 controls the transmission torque of the electronic control coupling 24 as follows.

  That is, after stopping the four-wheel drive control in the previous step S105, the ECU 26 determines whether the current traveling state of the vehicle 11 is a steady traveling state (first traveling state) (step S106). The steady traveling state refers to a state in which the vehicle is traveling at a constant vehicle speed on a highway or the like. Specifically, the ECU 26 determines whether the following condition (C) is satisfied.

· Amount of change of vehicle speed per unit time (speed change) <threshold value ΔV (C)
The ECU 26 determines that the vehicle 11 is in a steady traveling state when the amount of change of the vehicle speed per unit time is smaller than the threshold value ΔV.

  When it is determined that the traveling state of the vehicle 11 is the first traveling state, specifically, when the ECU 26 determines that the condition (C) is satisfied (YES in step S106), the ECU 26 performs the electronically controlled coupling 24. Is set to the set value α1 (step S107), and the process is ended.

  The set value α1 is set to, for example, a small value of about 5% to 10%. This is based on the viewpoint of reducing the impact accompanying the transmission of the rotational force of the rear wheels 28 and 28 to the motor 23 when power generation is started in the steady running state. By setting the transmission torque of the electronic control coupling 24 to a smaller value, the impact when the torque of the rear wheel starts to be transmitted to the motor 23 through the electronic control coupling 24 (the braking force generated along with the regenerative power generation) Occurrence of sudden breaking phenomenon etc. caused by Thereby, the ride comfort of the vehicle 11 is also ensured.

  When it is determined that the traveling state of the vehicle 11 is not the first traveling state, specifically, it is determined that the condition (C) is not satisfied (NO in step S106), the ECU 26 shifts the processing to step S108. Do.

  In step S108, the ECU 26 determines whether the current traveling state of the vehicle 11 is traveling downhill (second traveling state). Specifically, the ECU 26 determines whether the following two conditions (D1) and (D2) are satisfied.

・ The depression of the accelerator pedal is released (accelerator off) ... (D1)
· Vehicle speed> Threshold value Vh1 ................................................... (D2)
When the vehicle speed is maintained at a certain speed while the accelerator is off, the vehicle 11 is considered to be down some slope.

  When it is determined that the traveling state of the vehicle 11 is the second traveling state, specifically, when it is determined that the two conditions (D1) and (D2) are both satisfied (step S108) YES), the transmission torque of the electronic control coupling 24 is set to the set value α2 (step S109), and the process is ended.

  The set value α2 is set to, for example, a value of approximately 30% to 50%. However, the set value α2 may be set to 100% when traveling on a long downhill or the like. This is because it is preferable to generate a larger regenerative braking force as the downhill is longer.

  When it is determined that the traveling state of the vehicle 11 is not the second traveling state, specifically, it is determined that at least one of the two conditions (D1) and (D2) does not hold (step S108). (NO), the process proceeds to step S110.

  In step S110, the ECU 26 determines whether the current traveling state of the vehicle 11 is a deceleration traveling state (third traveling state) according to the driver's intention. Specifically, the ECU 26 determines whether the following two conditions (E1) and (E2) are satisfied.

・ The brake pedal is depressed (brake on) ... (E1)
Vehicle speed> Threshold value Vh2 .................................. (E2)
However, the threshold value Vh2 is set to a value smaller than the threshold value Vh2 in the above condition (D2), for example, 0 km / h.

  When it is determined that the traveling state of the vehicle 11 is the third traveling state, specifically, it is determined that the two conditions (E1) and (E2) are both satisfied (step S110). YES), the transmission torque of the electronic control coupling 24 is set to the set value α3 (step S111), and the process is ended.

  The set value α3 is set to, for example, a value of approximately 50% to 100%. In the case where the depression amount of the brake pedal is large or the like, since the driver's intention to stop is strong, the set value α3 may be set to 100%.

  However, it is preferable to gradually increase the transmission torque of the electronic control coupling 24 from the current value to the set value α3 instead of rapidly increasing it. This is to reduce an impact caused by a sudden change in the rotational force (torque) of the rear wheels 28, 28 transmitted to the motor 23. The same applies to changing the transmission torque from the current value to the set values α1 and α2 in the previous steps 107 and S109.

  When it is determined that the traveling state of the vehicle 11 is not the third traveling state, specifically, it is determined that at least one of the two conditions (E1) and (E2) does not hold (step S110). NO), end the process.

  The storage battery 21 is charged by supplying power generated by the motor 23 to the storage battery 21. When the amount of charge of storage battery 21 recovers to the extent that it exceeds threshold value X (YES in step S102), ECU 26 executes four-wheel drive control. The four-wheel drive control includes the following process.

  That is, the ECU 26 first sets the transmission torque of the electronic control coupling 24 to 0%. As a result, when regenerative power generation by the motor 23 is performed before execution of four-wheel drive control, the regenerative power generation is stopped. Next, when the depression of the accelerator pedal (accelerator on) is detected, the ECU 26 sets the transmission torque of the electronic control coupling 24 to 100%. Thereafter, the ECU 26 controls the rotation of the motor 23 to control the driving force transmitted to the rear wheels 28, 28.

<Effect of the embodiment>
Therefore, according to the present embodiment, the following effects can be obtained.
(1) While the vehicle is traveling, when the charge amount of the storage battery 21 falls below the threshold X and the traveling state where the four-wheel drive performance is not necessarily required, the power generation by the motor 23 is started. When the charge amount of the storage battery 21 recovers, the power generation by the motor 23 is ended. More appropriate regenerative power generation is performed according to the charge amount of the storage battery 21, whereby generation of unnecessary surplus power by the motor 23 is suppressed. Further, since overcharging of the storage battery 21 is also suppressed, maintenance and improvement of the product life of the storage battery 21 can be achieved.

  (2) Here, as the rotational force transmitted to the motor 23 is larger, the amount of power generation of the motor 23 increases. At this time, not only the power generation amount but also the regenerative braking force by the motor 23 increases. Therefore, depending on the traveling state of the vehicle 11, due to the regenerative braking force by the motor 23, there is a possibility that the driver may feel a slight impact. Therefore, as in the present embodiment, when power generation by the motor 23 is started, if the transmission torque of the electronic control coupling 24 is set to different values (α1, α2, α3) according to the traveling state of the vehicle 11, More appropriate regenerative power generation is performed according to the driving condition. Further, since it is possible to generate a more appropriate regenerative braking force according to the traveling state of the vehicle, the ride comfort of the vehicle is also secured.

  (3) When setting the transmission torque of the electronic control coupling 24 when starting power generation by the motor 23, the ECU 26 gradually changes from the transmission torque before the setting to a specific setting value (α1, α2, α3) Let In this way, it is possible to reduce the impact associated with the sudden change of the transmission torque of the electronic control coupling 24. The larger the difference between the transmission torque before setting and the target setting values (α1, α2, α3), the more effective.

  (4) Even when a decrease in the remaining amount of the storage battery 21 is detected, when the traveling state requires four-wheel drive, the four-wheel drive is prioritized over charging of the storage battery. Thereby, the running stability of the vehicle 11 can be secured continuously.

  (5) By controlling the transmission torque of the electronic control coupling 24, the torque transmitted from the motor 23 to the rear wheels 28, 28 can be controlled. For this reason, a motor with high precision is unnecessary.

  (6) A shunt DC machine is employed as the motor 23. At the time of power generation (during regeneration), for example, although it is possible to control the amount of power generation of the motor 23 by controlling the field current, in this case it is necessary to provide a configuration such as a circuit for controlling the field current. . In this respect, in the present embodiment, the amount of power generation of the motor 23 can be controlled by adjusting the transmission torque of the electronic control coupling 24. Since it is not necessary to control the field current applied to the motor 23, the configuration of a circuit or the like for controlling the field current is unnecessary.

Second Embodiment
Next, a second embodiment of the power transmission device will be described. The power transmission device of this example basically has the same configuration as the power transmission device shown in FIG. 1 described above, and is the first embodiment in terms of the processing procedure of power transmission control by the ECU. It is different from

  The procedure of the power transmission control of this embodiment is as shown in the flowchart of FIG. The processes in steps S101 to S103 of the flowchart are the same as those in the first embodiment, and thus detailed descriptions of those processes will be omitted.

  Now, as shown in the flowchart of FIG. 3, when the ECU 26 determines that the storage battery 21 needs to be charged, that is, when it is determined that the charge amount of the storage battery 21 does not exceed the threshold X YES in step S102) and cancel four-wheel drive control (step S201). Thereafter, the ECU 26 controls the transmission torque of the electronic control coupling 24 according to the traveling state of the vehicle 11 (step S202).

However, at least one of the following three processing groups having “·” at the beginning of the sentence may be included as the processing content of step S202.
A series of processes for determining the first traveling state (steady traveling) and controlling the transmission torque of the electronic control coupling 24 according to the determined traveling state (FIG. 2: S106, S107).

A series of processes for determining the second traveling state (downhill traveling) and controlling the transmission torque of the electronic control coupling 24 according to the determined traveling state (FIG. 2: S108, S109).
A series of processes of determining the third traveling state (decelerating traveling) and controlling the transmission torque of the electronic control coupling 24 according to the determined traveling state (FIG. 2: S110, S111).

Therefore, according to the present embodiment, the same effects as (1) to (3), (5) and (6) in the first embodiment can be obtained.
(7) Further, in the present embodiment, when the charge amount of the storage battery 21 does not reach the threshold value X, the storage battery 21 is always charged according to the traveling state of the vehicle 11 regardless of necessity of four-wheel drive. For this reason, it is suitable when you want to give priority to charge of the storage battery 21 to four-wheel drive.

Third Embodiment
Next, a third embodiment of the power transmission device will be described. The present embodiment differs from the first embodiment in that two left and right rear wheels are driven by two independent motors.

  As shown in FIG. 4, the power transmission device 22 has two motors 23 a and 23 b as auxiliary driving sources for traveling, two electronic control couplings 24 a and 24 b, and an ECU 26. The two motors 23a, 23b are connected to the left and right rear wheels 28, 28 via electronic control couplings 24a, 24b, respectively. The driving forces of the two motors 23a and 23b are respectively transmitted to the two rear wheels 28 and 28 via the corresponding electronic control couplings 24a and 24.

  The ECU 26 controls the two motors 23a, 23b and the two electronic control couplings 24a, 24 respectively. The ECU 26 executes the power transmission control for the two rear wheels 28, 28 basically in the same procedure as the procedure shown in the flowchart of FIG. 2 or FIG. 4 described above. When the charge amount of the storage battery 21 does not reach the threshold value X, the ECU 26 stops the motor 23 and controls the transmission torque of the electronic control coupling 24 according to the traveling state of the vehicle 11. Thereby, the regenerative charging of the storage battery 21 is performed according to the traveling state of the vehicle 11. In addition, regenerative braking force is exerted according to the traveling state of the vehicle.

Therefore, according to the present embodiment, the same effects as (1) to (6) of the first embodiment or the same effects as (7) of the second embodiment can be obtained.
<Other Embodiments>
The embodiments may be modified as follows.

  In the second embodiment, at the time of regenerative charging, the transmission torque of the electronic control coupling 24 is set according to at least one of the first to third traveling states. The same may be applied to the first and third embodiments.

  In the first to third embodiments, when performing regenerative power generation by the motor 23 (FIG. 2: S107, S109, S110, FIG. 3: S202), the transmission torque of the electronically controlled coupling 24 is calculated based on the vehicle speed V only. It may be set. Since the rotational force of the rear wheels 28, 28 changes depending on the vehicle speed, even if the transmission torque is set based only on the vehicle speed, according to the traveling state of the vehicle 11 (for example, low speed traveling, medium speed traveling, high speed traveling) It is possible to generate a more appropriate regenerative braking force.

  In the first or second embodiment, a single electronically controlled coupling 24 is provided between the motor 23 and the rear differential gear 25, but may be as follows. For example, electronically controlled couplings 24 are provided between the rear differential gear 25 and one rear wheel 28, and between the rear differential gear 25 and the other rear wheel 28, respectively. Also in this case, regenerative power generation can be performed according to the traveling state of the vehicle 11 through the control of the transmission torque of the electronic control coupling 24. Further, a more appropriate regenerative braking force is exerted according to the traveling state of the vehicle 11.

  -In 1st-3rd embodiment, although the vehicle 11 which has the internal combustion engine 12 was illustrated as a drive source of the front wheels 16 and 16 which are main driving wheels, it replaces with the internal combustion engine 12 and a motor (motor) is mounted. Vehicle may be used.

  In the first to third embodiments, the vehicle 11 is exemplified in which the front wheels 16 and 16 are main drive wheels and the rear wheels 28 and 28 are auxiliary drive wheels, but the rear wheels 28 and 28 are main drive wheels and front wheels The vehicle may be one in which 16, 16 are auxiliary drive wheels.

  11 Vehicle (four-wheel drive vehicle) 16 Front wheel (main drive wheel) 21 Storage battery 22 Power transmission device 23 Motor 23a Motor (first motor) 23b Motor (second) Motors, 24 ... electronically controlled coupling, 24a ... electronically controlled coupling (first coupling), 24b ... electronically controlled coupling (second coupling), 25 ... rear differential gear (differential mechanism), 26 ... ECU (control device), 28 ... rear wheel (secondary drive wheel).

Claims (8)

A power transmission apparatus for transmitting power to the auxiliary driving wheels of a four-wheel drive vehicle having left and right main driving wheels to which power is constantly transmitted and left and right auxiliary driving wheels to which power is transmitted according to a traveling state,
The power supplied from the on-board storage battery is consumed and rotated to generate the power transmitted to the auxiliary drive wheel, while the power supply is stopped by rotating in conjunction with the auxiliary drive wheel. A motor that generates power regenerated by the storage battery;
A coupling that continuously changes the power transmission ratio between the motor and the auxiliary drive wheel between 0% and 100% through electronic control;
A controller for controlling the motor and the coupling respectively;
The control device stops the power supply to the motor and sets the power transmission ratio to a value larger than 0% when the remaining amount of the storage battery falls below a predetermined threshold while the vehicle is traveling. By setting, the power generation by the motor is started, and when the remaining amount of the storage battery recovers beyond a predetermined threshold, the power transmission ratio is set to 0% to end the power generation by the motor. On the premise that
The power transmission ratio set when power generation by the motor is started is set to a different value according to the traveling state of the vehicle,
The traveling state of the vehicle includes at least a traveling state traveling at a constant speed and a traveling state decelerating by a brake,
The power transmission ratio set when power generation by the motor is started in a traveling state traveling at a constant speed is the power transmission set when power generation by the motor is started in a traveling state decelerated by a brake Power transmission set to a value smaller than the rate . A power transmission apparatus for transmitting power to the auxiliary driving wheels of a four-wheel drive vehicle having left and right main driving wheels to which power is constantly transmitted and left and right auxiliary driving wheels to which power is transmitted according to a traveling state,
The power supplied from the on-board storage battery is consumed and rotated to generate the power transmitted to the auxiliary drive wheel, while the power supply is stopped by rotating in conjunction with the auxiliary drive wheel. A motor that generates power regenerated by the storage battery;
A coupling that continuously changes the power transmission ratio between the motor and the auxiliary drive wheel between 0% and 100% through electronic control;
A controller for controlling the motor and the coupling respectively;
The control device stops the power supply to the motor and sets the power transmission ratio to a value larger than 0% when the remaining amount of the storage battery falls below a predetermined threshold while the vehicle is traveling. By setting, the power generation by the motor is started, and when the remaining amount of the storage battery recovers beyond a predetermined threshold, the power transmission ratio is set to 0% to end the power generation by the motor. On the premise that
The power transmission ratio set when power generation by the motor is started is set to a different value according to the traveling state of the vehicle ,
The traveling state of the vehicle includes at least a traveling state traveling at a constant speed and a traveling state inertially traveling on a downhill,
The power transmission ratio set when power generation by the motor is started in a traveling state traveling at a constant speed is set when power generation by the motor is started in a traveling state in which the motor travels downhill by inertia. Power transmission set to a value smaller than the power transmission ratio . In the power transmission device according to claim 1 or 2,
The power transmission device, wherein the control device gradually changes from the power transmission ratio before the setting to the power transmission ratio after the setting when setting the power transmission ratio when the power generation by the motor is started. The power transmission device according to any one of claims 1 to 3.
The control device maintains the power transmission ratio at 100% when a traveling state requiring four-wheel drive is detected, even when the remaining amount of the storage battery falls below a predetermined threshold value. And a power transmission device for driving the left and right auxiliary drive wheels through control of the motor. In the power transmission device according to claim 4,
The control device is a power transmission device that detects a traveling state in which four-wheel drive is required based on at least one of front and rear wheel speed differences and left and right wheel speed differences. The power transmission device according to any one of claims 1 to 5.
It has a differential mechanism that distributes the power of the motor to the left and right auxiliary drive wheels,
The power transmission device, wherein the coupling is provided between the motor and the differential mechanism. The power transmission device according to any one of claims 1 to 5.
The power transmission device includes the first and second motors, and the first and second motors are respectively coupled to the left and right auxiliary drive wheels via the coupling. In the power transmission device according to any one of claims 1 to 7,
Traveling state of the vehicle includes a first driving state of traveling at a constant speed, a second driving state of coasting downhill, and a third driving state to decelerate the brake,
The control device determines the first traveling state based on the vehicle speed, the second traveling state based on the operating state of the vehicle speed and the accelerator, and the third traveling state based on the operating state of the vehicle speed and the brake. Transmission device.