JP5328482B2 - Vehicle drive device - Google Patents

Description

  The present invention relates to a vehicle drive device in which two electric motors are provided together with an internal combustion engine as a vehicle drive source.

  The internal combustion engine and the first motor / generator are connected to a power split mechanism configured as a planetary gear mechanism, and the power output from the power split mechanism is transmitted to the output shaft, and the second motor / generator is connected to the output shaft. It is configured to add power through a speed change mechanism, and a shock that may occur when the speed ratio of the speed change mechanism is switched is eliminated by correcting the power of at least one of the first motor / generator and the internal combustion engine. A vehicle drive device is known (Patent Document 1). In addition, there is Patent Document 2 as a prior art document related to the present invention.

Japanese Patent Laid-Open No. 2004-203220 JP 2001-260669 A

  The drive device of Patent Document 1 can execute an electric drive mode using the second motor / generator as a drive source while the internal combustion engine is stopped. Since the internal combustion engine is stopped in the electric drive mode, the reaction force of the first motor / generator cannot be sufficiently received by the rotating element connected to the internal combustion engine. Therefore, since the power of the first motor / generator cannot be sufficiently transmitted to the output member, the above-described shock may not be resolved in the electric drive mode even if the power of the first motor / generator is corrected.

  Therefore, an object of the present invention is to provide a vehicle drive device that can alleviate a shock that may occur at the time of switching a gear ratio in the electric drive mode.

The drive device of the present invention has three rotation elements that can rotate differentially with each other, and one of the three rotation elements has the first rotation element as the internal combustion engine, and the other second rotation element has the first rotation element. A power split mechanism in which one remaining motor is connected to an output member, a second motor that can add power to a power transmission path from the output member to a drive wheel, A speed change mechanism capable of shifting the rotation of the second motor, switching the speed ratio to a plurality of speed ratios and transmitting the speed ratio to the power transmission path, and at least one of the first motor and the second motor, In a vehicle drive device capable of switching between a hybrid drive mode using an internal combustion engine as a drive source and an electric drive mode using the second electric motor as a drive source in a state where the operation of the internal combustion engine is stopped, the internal combustion machine A one-way clutch that allows rotation of the first rotation element in a predetermined direction that is the same direction as the rotation direction of the first rotation element and prevents rotation of the first rotation element in a direction opposite to the predetermined direction; and during the electric drive mode When the speed ratio of the speed change mechanism is switched, the shock caused by the change is alleviated by transmitting the power of the first motor to the power transmission path via the one-way clutch . And a shift correction means for correcting the power of the electric motor.

  According to this drive device, the reaction force of the first motor can be received by the one-way clutch while the internal combustion engine is stopped, so that the power of the first motor is sufficiently transmitted to the power transmission path from the output member to the drive wheels. it can. Therefore, by correcting the power of the first motor at the time of switching the gear ratio in the electric drive mode, it is possible to mitigate a shock that may occur at the time of switching.

  In the drive device of the present invention, the transmission mechanism is provided with a high-speed side high-speed transmission ratio and a low-speed side low-speed transmission ratio as the plurality of transmission ratios. When the speed ratio of the speed change mechanism is switched from the low speed speed ratio to the high speed speed ratio in the electric drive mode, the power of the first electric motor may be corrected to increase. According to this aspect, the power transmitted to the power transmission path can be increased by correcting the power of the first electric motor to the increase side. Therefore, since the power of the second motor that is insufficient when switching from the low speed gear ratio to the high speed gear ratio can be supplemented by the first motor, the shock that may occur due to the lack of power of the second motor is reduced. Can do.

  In this aspect, the operation member that receives a predetermined operation of the driver that reflects the intention to select the electric drive mode, and the speed change mechanism of the transmission mechanism when the operation member receives the predetermined operation while the vehicle is stopped. And a start time control means for starting the vehicle in the electric drive mode by switching the ratio to the low speed transmission ratio and controlling at least one of the first electric motor and the second electric motor. (Claim 3). In this case, when the vehicle is started in the electric drive mode, it is possible to reduce the burden on each motor because the speed ratio is switched to the low speed.

  In addition, an acceleration operation member that is operated according to the degree of the acceleration request of the driver is further provided, and the start time control means is configured to change the speed of the transmission mechanism when the operation amount of the acceleration operation member is small when the vehicle is stopped. The ratio is changed to the high speed gear ratio, and when the operation amount of the acceleration operation member is large, the gear ratio of the transmission mechanism is switched to the low speed gear ratio, and either the hybrid drive mode or the electric drive mode is selected. The vehicle may be started in the mode (Claim 4). Since the gear ratio is selected according to the degree of the driver's acceleration request, a start operation suitable for the driver's request is possible. That is, when the operation amount of the acceleration operating member is small and the acceleration request is low, the start can be started slowly by switching to the high speed gear ratio, while the acceleration operation member is large and the acceleration request is high. By switching to the low speed gear ratio, a sharp start can be made.

  As described above, according to the driving device of the present invention, the reaction force of the first motor can be received by the one-way clutch while the internal combustion engine is stopped. By correcting the power of the electric motor, a shock that may occur at the time of switching can be reduced.

The figure which showed schematically the whole structure of the vehicle to which the drive device which concerns on one form of this invention was applied. The flowchart which showed an example of the control routine of shock relaxation control. Explanatory drawing which showed the alignment chart at the time of execution of step S5 of FIG. The flowchart which showed an example of the control routine of control at the time of start.

  FIG. 1 schematically shows the overall configuration of a vehicle to which a drive device according to an embodiment of the present invention is applied. The vehicle 1 is configured as a so-called hybrid vehicle. As is well known, a hybrid vehicle is a vehicle that includes an internal combustion engine as a driving force source for traveling and also includes an electric motor as another driving force source for traveling. The vehicle 1 is configured as an FF layout vehicle in which drive wheels and an internal combustion engine are located at the front of the vehicle.

  The drive device 2 receives the internal combustion engine 3, the first motor / generator 4, the power split mechanism 5 to which the internal combustion engine 3 and the first motor / generator 4 are connected, and the power from the power split mechanism 5. The output gear 6 as an output member, the second motor / generator 7, the power transmission mechanism 8 for transmitting the power output from the output gear 6 to the drive wheels 10, and the rotation of the second motor / generator 7 are changed. And a speed change mechanism 9 for transmitting to the power transmission mechanism 8.

  The internal combustion engine 3 is configured as a spark ignition type multi-cylinder internal combustion engine, and the power is transmitted to the power split mechanism 5 via the input shaft 15. The input shaft 15 is arranged coaxially with the output gear 6, and the input shaft 15 and the output gear 6 rotate about the axis Ax1. A damper (not shown) is interposed between the input shaft 15 and the internal combustion engine 3, and torque fluctuations of the internal combustion engine 3 are absorbed by the damper. The first motor / generator 4 and the second motor / generator 7 have the same configuration, and have both a function as an electric motor and a function as a generator. The first motor / generator 4 corresponds to the first electric motor according to the present invention, and the second motor / generator 7 corresponds to the second electric motor according to the present invention.

  The power split mechanism 5 is configured as a single-pinion type planetary gear mechanism having three rotational elements that can rotate differentially with each other. The power split mechanism 5 is coaxial with the sun gear S that is an external gear and the sun gear S. A ring gear R, which is an internal gear disposed, and a carrier C that holds the pinion 20 meshing with the gears S and R so as to rotate and revolve freely. In this embodiment, the input shaft 15 is connected to the carrier C, the first motor / generator 4 is connected to the sun gear S, and the output gear 6 is connected to the ring gear R. Accordingly, the carrier C corresponds to the first rotating element according to the present invention, the sun gear S corresponds to the second rotating element according to the present invention, and the ring gear R corresponds to the third rotating element according to the present invention.

  A one-way clutch 25 is provided on the input shaft 15 that transmits the power of the internal combustion engine 3. The one-way clutch 25 allows the input shaft 15 to rotate in a predetermined direction that is the same as the rotation direction of the internal combustion engine 3 and prevents the input shaft 15 from rotating in the direction opposite to the predetermined direction. Since the input shaft 15 is connected to the carrier C of the power split mechanism 5, the rotation direction of the carrier C is also regulated by the one-way clutch 25, similarly to the input shaft 15.

  The power transmission mechanism 8 includes a counter shaft 30 disposed on an axis Ax2 parallel to the axis Ax1, and a differential device 31 that distributes the power output from the counter shaft 30 to the drive wheels 10. The differential device 31 and the drive wheel 10 are connected by a drive shaft 32. The counter shaft 30 is provided with a counter gear 33 that meshes with the output gear 6 and a drive gear 34 that meshes with the ring gear 31 a of the differential device 31. The power transmission mechanism 8 serves as a power transmission path for transmitting the power of the output gear 6 to the drive wheels 10 from the output gear 6 via the counter gear 33, the counter shaft 30, the differential device 31 and the drive shaft 32. A route to reach is formed. The power transmission path corresponds to the power transmission path according to the present invention.

  The transmission mechanism 9 includes a low-speed gear pair 35 that realizes a low-speed gear ratio, a high-speed gear pair 36 that realizes a high-speed gear ratio, and switching that selectively establishes one of the gear pairs 35 and 36. And a mechanism 37. The low-speed gear pair 35 is coaxial with the motor shaft 38 of the second motor / generator 7 and is provided with a low-speed drive gear 35A provided in a relatively rotatable state, and meshes with the low-speed drive gear 35A and is connected to the counter shaft 30. And a low-speed driven gear 35B that is fixed. The high-speed gear pair 36 is a high-speed drive gear 36A that is coaxial with the motor shaft 38 and is relatively rotatable, and a high-speed drive gear 36A that meshes with the high-speed drive gear 36A and is fixed to the counter shaft 30. And a driven gear 36B. The switching mechanism 37 has a low speed position where the low speed drive gear 35A and the motor shaft 38 are coupled so that they rotate together, and a high speed where the high speed drive gear 36A and the motor shaft 38 are coupled so that they rotate together. The operation position can be switched between the position and the release position where the coupling between each drive gear 35A, 36A and the motor shaft 38 is released. FIG. 1 shows a state where the switching mechanism 37 is switched to the release position.

  The drive device 2 is provided with a vehicle control device 40 that controls each part of the drive device 2 in order to realize switching of various drive modes. The vehicle control device 40 is configured as a computer unit, and holds various control programs for obtaining an appropriate traveling state of the vehicle 1. The vehicle control device 40 executes control of the control objects such as the internal combustion engine 3 and the motor / generators 4 and 7 by executing these programs.

  The drive modes realized by the drive device 2 are classified into a forward mode in which the vehicle 1 is moved forward and a reverse mode in which the vehicle 1 is moved backward according to the traveling direction of the vehicle 1. The forward mode includes a low speed mode executed when the vehicle 1 is at a low vehicle speed and a high speed mode executed at a high vehicle speed. Switching between the forward mode and the reverse mode is performed according to the operation of the shift lever 41 mounted on the vehicle 1. The shift position assigned to the shift lever 41 includes a drive position, a reverse position, a parking position, and a neutral position. The operation position of the shift lever 41 is output to the vehicle control device 40 through the shift position sensor 42. For example, the vehicle control device 40 switches the drive mode to the forward mode when the shift lever 41 is operated to the drive position, and switches the drive mode to the reverse mode when the shift lever 41 is operated to the reverse position. Switching between the low speed mode and the high speed mode is performed by operating the speed change mechanism 9 during execution of the forward mode. The operation is performed together with the vehicle speed of the vehicle 1 and the operation amount of the accelerator pedal 43 (accelerator opening degree) as an acceleration operation member. ) Based on a predetermined shift map defined as a variable. The vehicle speed and the accelerator opening are acquired by the vehicle speed sensor 44 and the accelerator opening sensor 45, respectively.

  Further, when the drive mode 2 is distinguished by the difference in the drive source, the hybrid that uses the internal combustion engine 3 as the drive source and at least one of the first motor / generator 4 and the second motor / generator 7. A drive mode and an electric drive mode using the second motor / generator 7 as a drive source in a state where the operation of the internal combustion engine 3 is stopped can be realized. Switching between the hybrid drive mode and the electric drive mode is performed in accordance with a traveling state such as a vehicle speed of the vehicle 1 and a charged state of a storage battery (not shown) mounted on the vehicle 1, and a driver who is an occupant of the vehicle 1. It is performed according to the operation. In the present embodiment, the driver can also select the electric drive mode. Therefore, the vehicle 1 is provided with an EV switch 46 as an operation member. The EV switch 46 can accept a push-in operation that is a predetermined operation of the driver that reflects the intention of selecting the electric drive mode, and outputs an operation signal to the vehicle control device 40 when the push-in operation is accepted.

  In addition to the basic control described above, the vehicle drive device 40 performs shock mitigation control and start time control described below as control related to the present invention.

  FIG. 2 is a flowchart illustrating an example of a control routine for shock relaxation control. The program of this routine is held in a storage device such as a ROM mounted on the vehicle control device 40, read out in a timely manner, and repeatedly executed at predetermined intervals.

  In step S1, the vehicle control device 40 determines whether or not the electric drive mode is being executed. If the electric drive mode is being executed, the vehicle control device 40 proceeds to step S2, and if not, the subsequent process is skipped and the routine is executed. finish.

  In step S2, it is determined whether or not the low speed mode is being executed, that is, whether or not the speed ratio of the speed change mechanism 9 is the low speed speed ratio. If the low-speed mode is being executed, the process proceeds to step S3. If not, the subsequent process is skipped and the routine is terminated.

  In step S3, it is determined whether or not there is a request for switching from the low speed mode to the high speed mode. The switching request for each mode is generated by another routine (not shown) executed in parallel with the control routine of FIG. 2 based on the above-described shift map. If there is a request for switching to the high speed mode, the process proceeds to step S4. If there is no request for switching, the subsequent process is skipped and the routine is terminated.

  In step S4, a speed change operation for switching the speed ratio of the speed change mechanism 9 from the low speed speed ratio to the high speed speed ratio is started. Specifically, the switching mechanism 37 provided in the transmission mechanism 9 is switched from the low speed position to the high speed position.

  In step S5, the power of the first motor / generator 4 is corrected to the increasing side, and the routine is terminated. The correction amount is calculated based on a predetermined logic based on various parameters such as the vehicle speed of the vehicle 1, the rotational speed of each motor / generator 4, 7 and power. FIG. 3 shows a nomograph when step S5 is executed. In the figure, “Eng” indicates the internal combustion engine 3, “MG1” indicates the first motor / generator 4, “MG2” indicates the second motor / generator 7, “OUT” indicates the output gear 6, and “OWC” indicates the one-way. Each of the clutches 25 is shown. As can be understood from FIG. 3, since the rotation of the carrier C in the direction opposite to the rotation direction of the internal combustion engine 3 is blocked by the one-way clutch 25, the reaction force of the power T <b> 1 of the first motor / generator 4 is reduced. Can be received at. In other words, a reaction force T3 is generated in the one-way clutch 25. Therefore, the power of the first motor / generator 4 can be sufficiently transmitted to the counter shaft 30 (FIG. 1) via the output gear 6. Therefore, the shortage of the power T2 of the second motor / generator 7 is compensated by the power T1 of the first motor / generator 4, and the power difference generated before and after the gear ratio switching can be reduced. As a result, shock that may occur before and after switching of the gear ratio can be mitigated.

  When the vehicle control device 40 executes the control routine shown in FIG. 2, the vehicle control device 40 functions as a shift correction means according to the present invention.

  FIG. 4 is a flowchart showing an example of a control routine for starting control. The program of this routine is held in the storage device of the vehicle control device 40, read out in a timely manner, and repeatedly executed at predetermined intervals. The execution conditions of the routine of FIG. 4 are set when the vehicle 1 is stopped, that is, when the vehicle speed is zero.

  In step S11, it is determined whether or not the shift position of the shift lever 41 is the reverse position. If it is the reverse position, the process proceeds to step S17, where the speed ratio of the speed change mechanism 9 is switched to the speed ratio for low speed, and the start control of the vehicle 1 is executed. Accordingly, in the reverse mode, the low speed required gear ratio is used at the time of start. This start control is well known to start the vehicle by controlling the internal combustion engine 3 and the motor generators 4 and 7 in response to a request for switching to the hybrid drive mode or the electric drive mode. On the other hand, if the shift position is not the reverse position, the process proceeds to step S12.

  In step S12, it is determined whether or not the shift position is a drive position. If it is the drive position, the process proceeds to step S13, and it is determined whether or not the EV switch 46 is ON, that is, whether or not a push-in operation is being performed. If the EV switch 46 is ON, the process proceeds to step S14, a request for switching to the electric drive mode is generated, and the process proceeds to step S17. In step S17, as described above, start control is performed by switching the gear ratio to the low speed gear ratio. On the other hand, if the EV switch 46 is not ON, the process proceeds to step S15.

  In step S15, it is determined whether or not the requested driving force by the driver is large, in other words, whether or not the acceleration request by the driver is large. The determination is made based on a threshold value set for the accelerator opening that is the operation amount of the accelerator pedal 43. That is, when the accelerator opening is equal to or exceeds the threshold, it is determined that the required driving force is large, and when the accelerator opening is below the threshold, it is determined that the required driving force is not large. When it is determined that the required driving force is large, the process proceeds to step S17, and the start control is performed by switching the gear ratio to the low speed gear ratio. As a result, the vehicle 1 having a sharp rise can be started. On the other hand, if it is determined that the required driving force is not large, that is, it is determined that the required driving force is small, the process proceeds to step S16, and the start control is performed by switching the gear ratio to the high speed gear ratio. As a result, the vehicle 1 can be started slowly.

  When the vehicle drive device 40 executes the control routine of FIG. 4, the vehicle control device 40 functions as a start time control unit according to the present invention.

  This invention is not limited to the said form, It can implement with a various form within the range of the summary of this invention. In the above embodiment, the shock mitigation control is performed by correcting the power of the first motor / generator 4 to the increase side when switching from the low speed gear ratio to the high speed gear ratio. Even when switching from the transmission gear ratio to the low speed transmission gear ratio, a power difference occurs before and after the switching. Therefore, the power of the first motor / generator 4 may be corrected in order to mitigate a shock caused by the power difference. The power correction direction at that time may be either on the increase side or the decrease side.

  The number of transmission gear ratios that can be switched by the transmission mechanism is not limited to two, but may be one that switches between three or more transmission gear ratios.

  The installation location of the one-way clutch 25 is not limited to the output shaft 15, and may be provided on the carrier C of the power split mechanism 5, for example. In short, the one-way clutch may be provided at any location as long as the rotation direction of the rotary element to which the internal combustion engine is coupled can be limited to one direction.

  Note that the configuration of the power split mechanism described above is merely an example, and it is possible to change this to another form that is mechanically equivalent. In addition, the connection relationship of the power split mechanism to each rotating element can be changed to another form. Furthermore, the configuration of the power split mechanism with a planetary gear mechanism is merely an example, and for example, a planetary roller mechanism having a friction wheel (roller) that is not a gear as a rotating element may be used.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Drive device 3 Internal combustion engine 4 1st motor generator (1st electric motor)
5 Power split mechanism 6 Output gear (output member)
7 Second motor / generator (second electric motor)
9 Transmission mechanism 25 One-way clutch 40 Vehicle control device (shift correction means, start control means)

Claims (4)

It has three rotating elements that can rotate differentially with each other, and one of the three rotating elements has the first rotating element as the internal combustion engine, the other second rotating element has the first motor, and the other one. A power split mechanism in which three third rotating elements are connected to the output member, a second electric motor that can add power to the power transmission path from the output member to the drive wheel, and the rotation speed of the second electric motor is changed. And a transmission mechanism capable of switching the transmission gear ratio to a plurality of transmission gear ratios and transmitting it to the power transmission path, wherein at least one of the first electric motor and the second electric motor and the internal combustion engine are used as a drive source. In a vehicle drive device capable of switching between a hybrid drive mode that performs and an electric drive mode that uses the second electric motor as a drive source while the operation of the internal combustion engine is stopped,
A one-way clutch that allows rotation of the first rotation element in a predetermined direction that is the same as the rotation direction of the internal combustion engine and prevents rotation of the first rotation element in a direction opposite to the predetermined direction; When the gear ratio of the transmission mechanism is switched in the drive mode, the shock accompanying the switching is reduced by transmitting the power of the first motor to the power transmission path via the one-way clutch. A vehicle drive device, further comprising a shift correction means for correcting the power of the first electric motor. The speed change mechanism is provided with a high speed side high speed gear ratio and a low speed side low speed gear ratio as the plurality of gear ratios,
The shift correction means corrects the power of the first motor to an increase side when the gear ratio of the transmission mechanism is switched from the low speed gear ratio to the high speed gear ratio in the electric drive mode. Item 2. The driving device according to Item 1.   An operation member that receives a predetermined operation of the driver reflecting the intention to select the electric drive mode, and a speed ratio of the transmission mechanism for the low speed when the operation member receives the predetermined operation while the vehicle is stopped. The start-time control means for starting the vehicle in the electric drive mode by switching to a gear ratio and controlling at least one of the first electric motor and the second electric motor. Drive device. It further comprises an acceleration operation member that is operated according to the degree of acceleration demand of the driver,
When the vehicle is stopped, the start time control means sets the gear ratio of the transmission mechanism to the high speed gear ratio when the operation amount of the acceleration operation member is small, and shifts the gear when the operation amount of the acceleration operation member is large. 4. The drive device according to claim 3, wherein the gear ratio of the mechanism is switched to the low speed gear ratio, and the vehicle is started in one of the hybrid drive mode and the electric drive mode.

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