JP2011006020A - Drive device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive device of a hybrid vehicle, capable of suppressing overheat of a second motor generator and keeping balance of income and outgo of electric power.SOLUTION: The drive device 1 includes a power-dividing mechanism 10 having a sun gear S, a ring gear R, and a carrier C as rotational elements capable of differentially rotating from each other, the carrier C being connected to an internal combustion engine 2, with the sun gear S connected to a first motor generator, and the ring gear R connected to a counter gear 15, respectively; a second motor generator 6 selectively connected to either one of the carrier C and the ring gear R; and a clutch 11 for switching the connection destination of the second motor generator 6 between the carrier C and the ring gear R, and switches the connection destination of the second motor generator 6 to avoid a specified state where electrification to the second motor generator 6 continues, in a state with the rotation of one of the rotational elements being connected to the second motor generator 6 stops.

Description

  The present invention relates to a drive device for a hybrid vehicle including a power split mechanism that splits the power of an internal combustion engine into a motor generator and the like.

  A power split mechanism having a first rotating element coupled to the internal combustion engine, a second rotating element coupled to the generator, and a third rotating element coupled to a drive shaft that transmits power to the drive wheels. There is a drive device for a hybrid vehicle. A drive device for such a hybrid vehicle, an assist motor connected to the drive shaft or the output shaft of the internal combustion engine, and a switching mechanism for switching the connection destination of the assist motor between the drive shaft and the output shaft of the internal combustion engine; Are further known (see Patent Document 1 (FIG. 17)). And a motor that outputs power and a clutch that connects and releases the drive shaft and the motor, and the rotation stop state in which the absolute value of the rotation number of the motor is equal to or less than a predetermined rotation number including zero is expected to exceed the expected time The clutch is controlled so that the connection between the drive shaft and the motor is released when the drive shaft continues, and the clutch is controlled so that the drive shaft and the motor are connected when a predetermined disconnection condition is satisfied after that. Is known (Patent Document 2). In addition, there is Patent Document 3 as a prior art document related to the present invention.

JP 2002-135910 A JP 2008-167633 A JP 2006-199077 A

  As an assist motor mounted on a hybrid vehicle, an AC synchronous motor including a stator having a three-phase coil and a rotor on which a permanent magnet is disposed may be used. In such a case, when the vehicle stops while outputting torque on a hill or the like, the drive device of the hybrid vehicle disclosed in Patent Document 1 stops rotation of the drive shaft while energizing the assist motor to output torque. As a result, the current concentrates on one phase of the stator and the assist motor and the inverter may be overheated. Moreover, in the drive device of Patent Document 2, when the second motor is overheated in a state where the rotation of the drive shaft is stopped, the connection between the second motor and the drive shaft is released, so that the overheating of the second motor can be suppressed. it can. However, the drive device of Patent Document 2 also includes a first motor for power generation. In a state where the connection between the second motor and the drive shaft is released, the internal combustion engine outputs torque so that the first motor is output. However, since the power consumption by the second motor is reduced, there is a large difference between the power generation amount of the first motor and the power consumption amount of the second motor. That is, in a state where the connection between the second motor and the drive shaft is released, the balance of power balance cannot be maintained between the first motor and the second motor.

  Accordingly, an object of the present invention is to provide a drive device for a hybrid vehicle capable of suppressing overheating of the second motor generator and maintaining a balance of power balance.

  The drive device for a hybrid vehicle of the present invention has three rotating elements that can rotate differentially with each other, the first rotating element is connected to the internal combustion engine, the second rotating element is connected to the first motor generator, A power split mechanism in which a rotating element is connected to an output member that outputs power to a driving wheel of a wheel, and is selectively connected to either the first rotating element or the third rotating element of the power split mechanism. The second motor generator, connection destination switching means for switching the connection destination of the second motor generator between the first rotation element and the third rotation element of the power split mechanism, and the second motor generator connected In order to avoid a specific state in which energization to the second motor generator continues in a state where the rotation of one of the rotating elements is stopped, the connection destination switching means causes the second The connection of the over data generator from one rotary element and a, and control means to switch to the other rotary element (claim 1).

  According to this hybrid vehicle drive device, it is possible to avoid continuation of energization of the second motor generator in a state in which the rotating element connected to the second motor generator is stopped. In order to avoid the specific state, the connection destination of the second motor generator is switched from one rotating element to the other rotating element while avoiding the specific state. Thereby, overheating of the second motor generator can be suppressed. Further, the first motor generator generates power when the internal combustion engine outputs torque. However, since the second motor generator can continue to rotate while outputting torque, the power consumption by the second motor generator is extreme. Can be prevented. Therefore, the balance of power balance can be maintained between the first motor generator and the second motor generator.

  In one aspect of the hybrid vehicle drive device of the present invention, the control means is configured such that the temperature of the second motor generator is equal to or higher than a predetermined temperature while the second motor generator is connected to one rotating element. Furthermore, the specific state may be avoided by switching the connection destination of the second motor generator from one rotation element to the other rotation element by the connection destination switching means (claim 2). In this case, overheating of the second motor generator can be reliably suppressed by setting the predetermined temperature lower than the overheating temperature.

  In one aspect of the hybrid vehicle drive device of the present invention, the control means is configured to switch the connection destination switching means when the rotational speed of one rotary element to which the second motor generator is connected is equal to or lower than a predetermined rotational speed. Thus, the specific state may be avoided by switching the connection destination of the second motor generator from one rotating element to the other rotating element (claim 3). In this case, since the connection destination of the second motor generator is the other rotation element before the rotation of the rotation element to which the second motor generator is connected stops, the specific state can be surely avoided.

  In one aspect of the hybrid vehicle drive device of the present invention, the control means stops rotation of one rotary element to which the second motor generator is connected, and the temperature of the second motor generator is a predetermined temperature. In this case, the specific state may be avoided by switching the connection destination of the second motor generator from one rotation element to the other rotation element by the connection destination switching means (Claim 4). . In this case, it is possible to prevent the connection destination from being frequently switched before the second motor generator is overheated.

  As described above, according to the present invention, since the connection destination of the second motor generator is switched so as to avoid the specific state, it is possible to suppress overheating of the second motor generator and to balance the power balance. Can keep.

It is a skeleton figure of the drive device of the hybrid vehicle concerning one form of the present invention, and is the figure showing the state where the 2nd motor generator is connected to the hollow shaft. It is a skeleton figure of the drive device of the hybrid vehicle concerning one form of the present invention, and is the figure showing the state where the 2nd motor generator is connected to the output shaft. The flowchart which shows an example of the switching control routine which a control unit performs. FIG. 6 is a collinear diagram of the power split mechanism when only the second motor generator is responsible for outputting power to the drive shaft. The alignment chart of a power split mechanism in case the internal combustion engine bears the output of the motive power to a drive shaft. FIG. 6 is an alignment chart of a power split mechanism when an internal combustion engine and a second motor generator are responsible for output of power to a drive shaft.

  1 and 2 are skeleton diagrams of a drive device according to an embodiment of the present invention. This drive device 1 is mounted on a hybrid vehicle. As shown in FIG. 1, the drive device 1 includes an internal combustion engine 2, a first motor generator 4, and a second motor generator 6. Since the internal combustion engine 2 may be the same as a known one mounted on a hybrid vehicle, a detailed description is omitted. The first motor generator 4 and the second motor generator 6 are configured as an AC synchronous motor including a stator (not shown) having a three-phase coil and a rotor (not shown) in which permanent magnets are arranged. The generator 4 mainly functions as a generator, and the second motor generator 6 mainly functions as an electric motor. An inverter (not shown) that converts direct current and alternating current between the motor generators 4 and 6 and a battery (not shown) is also provided. The drive device 1 outputs a power split mechanism 10 interposed between the output shaft 2 a and the first motor generator 4 and a connection destination of the second motor generator 6 in a direction along the output shaft 2 a of the internal combustion engine 2. A clutch 11 is provided as connection destination switching means for switching between the shaft 2 a and the power split mechanism 10.

  The power split mechanism 10 is configured as a planetary gear mechanism having three rotating elements that can be differentially rotated with each other, and includes a sun gear S that is an external gear and an internal tooth that is coaxially disposed with respect to the sun gear S. A ring gear R, which is a gear, and a carrier C that holds a pinion that meshes with the gears S and R so as to rotate and revolve freely. In this embodiment, the carrier C is connected to the output shaft 2a, the sun gear S is connected to the first motor generator 4, and the ring gear R is connected to the counter gear 15 and the hollow shaft 16 as output members. Therefore, the sun gear S corresponds to the second rotating element according to the present invention, the ring gear R corresponds to the third rotating element according to the present invention, and the carrier C corresponds to the first rotating element according to the present invention. A gear 18 is connected to the counter gear 15 via a counter shaft 17. The gear 18 is in mesh with the drive gear 19. The drive gear 19 is provided on the drive shaft 20 and rotates integrally with the drive shaft 20. Therefore, the power output from the internal combustion engine 2 and the second motor generator 6 is transmitted to the drive shaft 20 via the power split mechanism 10. Drive wheels 21 are provided on the drive shaft 20.

  The clutch 11 includes a first engagement disk 25, a second engagement disk 26, an operation disk 27, and an actuator (not shown). The first engagement disk 25 is connected to the hollow shaft 16 and the second engagement disk 26 is connected to the output shaft 2a so as to rotate together. The second motor generator 6 is connected to the operation disk 27. Further, the operation disk 27 is configured to be operable from a first engagement state where the operation disk 27 is engaged with the first engagement disk 25 to a second engagement state where the operation disk 27 is engaged with the second engagement disk 26. The operation disk 27 is driven by an actuator. The engagement between these disks may be performed by a well-known mechanism generally used in a clutch. For example, a dry or wet engagement mechanism, or each disk is provided with dog teeth, and the dog teeth are engaged with each other. A dog mechanism that engages each other may be applied.

  FIG. 1 shows a first engagement state, and FIG. 2 shows a second engagement state. As shown in FIG. 1, in the first engagement state, the operation disk 27 is engaged with the first engagement disk 25, so that the power output from the second motor generator 6 is transmitted to the hollow shaft 16. Since the hollow shaft 16 is also connected to the ring gear R, the power output from the second motor generator 6 is transmitted to the counter gear 15 via the ring gear R, and is transmitted to the drive wheels 21 via the counter gear 15. The That is, in the first engagement state, the power output from the second motor generator 6 is transmitted to the drive wheels 21 via the ring gear R.

  On the other hand, as shown in FIG. 2, in the second engagement state, since the operation disk 27 is engaged with the second engagement disk 26, the power output from the second motor generator 6 is transmitted to the output shaft 2a. The Further, since the output shaft 2a is connected to the carrier C, the power output from the second motor generator 6 is transmitted to the carrier C through the output shaft 2a.

  The operation of the actuator is controlled by a control unit 30 configured as a computer for appropriately controlling the states of the motor generators 4 and 6. That is, the clutch 11 is controlled between a first engagement state in which the operation disk 27 engages with the first engagement disk 25 and a second engagement state in which the operation disk 27 engages with the second engagement disk 26. The state is switched by the unit 30. The control unit C30 controls the operation of the actuator according to a predetermined program while referring to signals output from various sensors (not shown). FIG. 3 is a flowchart illustrating an example of a switching control routine executed by the control unit 30. The program of this routine is stored in the control unit 30, and is read out in a timely manner and repeatedly executed at predetermined intervals.

  In step S1, the control unit 30 determines whether the rotation of the drive shaft 20 is stopped based on information acquired from a sensor (not shown). If this determination is negative, the subsequent steps are terminated by skipping the subsequent steps. On the other hand, if the determination in step S1 is affirmative, the process proceeds to step S2. In step S2, it is determined whether or not the temperature of the second motor generator 6 is equal to or higher than a predetermined temperature that is determined to be overheating. If this determination is negative, the subsequent steps are terminated by skipping the subsequent steps. On the other hand, if the determination in step S2 is affirmative, the process proceeds to step S3. In the subsequent step S3, the state is switched so that the clutch 11 is in the second engagement state, and the current routine is terminated.

  On a slope or the like, the drive shaft 20 may stop rotating while power is output to the drive shaft 20. 4 to 6 are collinear diagrams showing the states of the rotating elements S, C, and R of the power split mechanism 10 in such a case. FIG. 4 shows a case where the clutch 11 is in the first engagement state and only the second motor generator 6 is responsible for the output of power to the drive shaft 20. In this case, as shown in FIG. 4, since the rotation of the drive shaft 20 is stopped, the rotational speed Td of the ring gear R connected to the drive shaft 20 via the counter gear 15 becomes zero, and other rotations occur. The rotational speeds Te and Tg of the elements S and C are all zero. When the rotational speeds Td, Te, and Tg of the rotating elements S, C, and R are all zero, the sun gear S is the first motor generator 4, the carrier C is the output shaft 2a of the internal combustion engine 2, and the ring gear R is the drive shaft. Since the second motor generator 6 is connected to the second motor generator 6 via the hollow shaft 16 and the hollow shaft 16, the drive shaft 20 does not rotate while the second motor generator 6 outputs power to the drive shaft 20. That is, the second motor generator 6 is in a motor lock state in which the rotational speed becomes zero while being energized. In such a motor lock state, current concentrates on one phase of the stator of the second motor generator 6, which may cause overheating of the second motor generator 6 and the inverter.

  On the other hand, FIG. 5 shows a case where the internal combustion engine 2 bears the output of power to the drive shaft 20 when the clutch 11 is in the first engagement state. In this case, as shown in FIG. 5, the state of each rotating element, that is, the state of each of the motor generators 4 and 6 and the internal combustion engine 2 is determined based on the rotational speed zero of the second motor generator 6 as the starting point. A relationship in which the rotational speed increases at a constant rate in the order of the motor generator 4 is shown. That is, in the state where the rotation of the drive shaft 20 is stopped, the first motor generator 4 is in a state where power is generated while the internal combustion engine 2 outputs power. In this case, since the motive power carried by the second motor generator 6 can be reduced, overheating of the second motor generator 6 can be suppressed. However, since power generation is performed by the first motor generator 4, when the battery is overcharged, it is necessary to discharge. In this case, it becomes necessary to increase the rotational speed of the second motor generator 6 again. When the rotational speed of the second motor generator 6 is increased, the motive power of the second motor generator 6 is increased, so that the second motor generator 6 and the inverter may be overheated again.

  According to this embodiment, the control unit 30 executes the routine of FIG. 3 so that the rotation of the drive shaft 20 is stopped, that is, the rotation of the ring gear R and the hollow shaft 16 is stopped. When the temperature is equal to or higher than a predetermined temperature that is determined to be overheating, control is performed so that the connection destination of the second motor generator 6 is the output shaft 2a. FIG. 6 shows a case where the internal combustion engine 2 and the second motor generator 6 bear the output of power to the drive shaft 20 when the clutch 11 is in the second engagement state. In this case, as shown in FIG. 6, the state of each rotating element is the same as that shown in FIG. 5, but the connection destination of the second motor generator 6 is the output shaft 2a of the internal combustion engine 2, that is, the carrier C. Since the carrier C can rotate, the second motor generator 6 can be rotated even when the drive shaft 20 is stopped. Thereby, since it can suppress that an electric current concentrates on one phase of the stator of the 2nd motor generator 6, it can suppress that the 2nd motor generator 6 and an inverter are overheated. In addition, power is generated by the first motor generator 4, but since the second motor generator 6 is rotating, power is also consumed. Thereby, while being able to maintain the balance of electric power balance between the 1st motor generator and the 2nd motor generator, overcharge of a battery can also be controlled. Further, when the second motor generator 6 is in a motor locked state and is at a predetermined temperature or higher, the connection destination of the second motor generator 6 is switched to the output shaft 2a of the internal combustion engine 2, so that the second motor generator 6 is overheated. It is possible to prevent the connection destination from being frequently switched before reaching. When the control unit 30 executes the routine of FIG. 3, the control unit 30 functions as the control means of the present invention.

  However, this invention is not limited to the above-mentioned form, It can implement with a various form within the range of the summary of this invention. In the above-described embodiment, the rotation of the drive shaft 20, that is, the rotation of the ring gear R to which the second motor generator 6 is connected is stopped, and the temperature of the second motor generator 6 is equal to or higher than a predetermined temperature that is determined to be overheating. In this case, the connection destination of the second motor generator 6 is switched to the output shaft 2a. However, the present invention is not limited to such a configuration. Since the motor lock state of the second motor generator 6 continues, the second motor generator 6 is overheated, so that the control unit 30 causes the clutch 11 to perform the second operation so as to avoid such a specific state where the motor lock state continues. As long as the connection destination of the motor generator 6 is switched from the output shaft 2a to the hollow shaft 16, for example, step S1 or step S2 in FIG. 3 may be omitted. In addition, the control unit 30 determines that the rotation speed of the ring gear R is lower when the rotation speed of the drive shaft 20 is less than or equal to the predetermined rotation speed based on a predetermined rotation speed that can be expected to stop the preset rotation. The connection destination of the second motor generator 6 may be switched so that the connection destination of the second motor generator 6 is changed from the hollow shaft 16 to the output shaft 2a when the rotation speed is equal to or lower than a predetermined rotation speed. In this case, since the connection destination of the second motor generator 6 becomes the output shaft 2a before the rotation of the ring gear R to which the second motor generator 6 is connected via the hollow shaft 16 stops, the specific state is ensured. Can be avoided. Further, the switching of the connection destination of the second motor generator 6 performed by the control unit 30 described above is limited to the case where the hollow shaft 16 is switched to the output shaft 2a, that is, the case where the ring gear R is switched to the carrier C. Instead, it may be applied when switching from the carrier C to the ring gear R.

DESCRIPTION OF SYMBOLS 1 Drive device 2 Internal combustion engine 4 1st motor generator 6 2nd motor generator 10 Power split mechanism 11 Clutch (connection destination switching means)
30 Control unit (control means)
S Sun gear (second rotating element)
C carrier (first rotating element)
R ring gear (third rotating element)

Claims (4)

It has three rotating elements that can rotate differentially with each other, the first rotating element is connected to the internal combustion engine, the second rotating element is connected to the first motor generator, and the third rotating element powers the driving wheels of the wheels. A power split mechanism connected to the output member for output;
A second motor generator selectively connected to either the first rotating element or the third rotating element of the power split mechanism;
Connection destination switching means for switching the connection destination of the second motor generator between the first rotation element and the third rotation element of the power split mechanism;
In order to avoid a specific state in which energization to the second motor generator is continued in a state in which the rotation of one rotary element to which the second motor generator is connected is stopped, the connection destination switching means causes the second motor generator to And a control means for switching the connection destination from one rotating element to the other rotating element.   When the temperature of the second motor generator is equal to or higher than a predetermined temperature in a state where the second motor generator is connected to one rotating element, the control means switches the second motor generator by the connection destination switching means. The drive device according to claim 1, wherein the specific state is avoided by switching the connection destination of the first rotation element from one rotation element to the other rotation element.   The control means rotates the connection destination of the second motor generator by one of the connection destination switching means when the rotation speed of one rotary element to which the second motor generator is connected is equal to or less than a predetermined rotation speed. The drive device according to claim 1, wherein the specific state is avoided by switching from one element to the other rotating element.   When the rotation of one rotating element to which the second motor generator is connected stops and the temperature of the second motor generator becomes equal to or higher than a predetermined temperature, the control means The drive device according to claim 1, wherein the specific state is avoided by switching a connection destination of the second motor generator from one rotating element to the other rotating element.

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