JP2022114130A - Drive unit for hybrid vehicle - Google Patents

Abstract

To provide a drive unit for a hybrid vehicle that can reduce a power loss when a torque is transmitted between a motor as a drive source and driving wheels.SOLUTION: In a drive unit for a hybrid vehicle 1 including: a transmission mechanism 4 including a plurality of planetary gear mechanisms 6, 7, 8 and configured to set a predetermined transmission gear ratio by connecting at least two rotation elements of the plurality of planetary gear mechanisms 6, 7, 8 or fixing any of the rotation elements; an engine 2 connected to an input side of the transmission mechanism 4; and a motor 3 having a power generation function, a bypass route 10 is provided that connects an input shaft 5 of the transmission mechanism 4 and an output shaft 9 of the transmission mechanism 4 so as to transmit a torque not via the plurality of planetary gear mechanisms 6, 7, 8.SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle drive system in which a speed change mechanism is connected to the output sides of an engine and a motor.

Patent Literature 1 describes a drive device for a hybrid vehicle provided with an engine and two motors as driving force sources. This drive device includes a power splitting mechanism in which an engine, a first motor, and an output shaft are coupled for differential rotation, and a stepped transmission mechanism coupled to the output shaft of the power splitting mechanism. A second motor is connected to the output shaft of the power split mechanism. In addition, the stepped transmission mechanism includes a plurality of planetary gear mechanisms, and an engagement mechanism such as a plurality of brake mechanisms that connect any rotating element of the planetary gear mechanism to a fixed portion such as a case. there is This hybrid vehicle is configured to cause the second motor to function as a generator when a braking request is made such as when the accelerator opening is "0". is configured to perform a downshift that increases the gear ratio of

JP 2007-050866 A

A drive system for a hybrid vehicle described in Patent Document 1 downshifts a stepped transmission mechanism when a braking request is made to increase the rotation speed of a second motor, thereby increasing the torque and rotation speed of the second motor. The fixed operating point is configured to be changed to an operating point at which the power generation efficiency of the second motor is improved. That is, it is configured to improve the generated power of the second motor with respect to the braking power acting on the output shaft of the second motor. On the other hand, since a stepped transmission mechanism having a plurality of gears is provided in the torque transmission path between the second motor and the drive wheels, slippage of the gears constituting the stepped transmission mechanism is a factor. Such an unavoidable power loss occurs. Therefore, in order to generate the required braking force (braking power), the braking torque (braking power) to be output from the second motor is reduced, which may reduce the amount of power generated by the second motor. Similarly, when the vehicle is driven by using the second motor as a driving force source, power loss occurs due to the stepped transmission in the process of transmitting the driving power generated at the output shaft of the second motor to the driving wheels. Therefore, in order to generate the required driving force (driving power), the driving torque (driving power) to be output from the second motor increases, and there is a possibility that the amount of electric power consumed by the second motor increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned technical problems, and is capable of reducing power loss when transmitting torque between a motor as a driving force source and drive wheels. The object is to provide an apparatus.

In order to achieve the above object, the present invention has a plurality of planetary gear mechanisms, and at least any two rotating elements of the plurality of planetary gear mechanisms are connected or at least one of the rotating elements is fixed. A drive system for a hybrid vehicle, comprising: a transmission mechanism configured to set a predetermined gear ratio by adjusting the speed of the transmission mechanism; and the output shaft of the speed change mechanism so that torque can be transmitted without intervening the plurality of planetary gear mechanisms.

According to the present invention, the path is provided for transmitting the torque of the engine and the motor via the transmission having a plurality of planetary gear mechanisms. Therefore, when the vehicle runs by outputting power from the engine, it is possible to control the gear ratio of the transmission mechanism and set the operating point of the engine to a fuel efficient operating point or the like. It also has a bypass path that transmits the torque of the engine and motor without going through the transmission mechanism. Therefore, when power is output from the motor, or when the motor is made to function as a generator, the torque is transmitted through the bypass path without going through the transmission mechanism, so that the torque is transmitted between the motor and the output shaft of the transmission mechanism. It is possible to reduce the power loss that occurs in Therefore, it is possible to reduce power consumption when driving the motor, and to increase the amount of power generated by the motor.

1 is a block diagram schematically showing an example of a hybrid vehicle to which the present invention can be applied; FIG. FIG. 2 is a skeleton diagram showing an example of the gear train of the automatic transmission and the bypass route; FIG. 11 is a skeleton diagram showing an example of a gear train forming another bypass route;

A hybrid vehicle according to an embodiment of the invention includes an engine, a motor, and a transmission mechanism. An example of this is schematically shown in FIG. The hybrid vehicle 1 shown here is an example of a four-wheel drive vehicle based on a front-engine, rear-wheel-drive vehicle (FR vehicle). Following the engine 2, a motor (MG) 3 and an automatic transmission (A/T) 4 are arranged in order. An engine 2 (more specifically, an output shaft of the engine 2) and a motor 3 (more specifically, a rotor shaft of the motor 3) are connected to an input shaft 5 of an automatic transmission 4. As shown in FIG. A spring damper or a torque converter (fluid coupling) may be provided between the engine 2 and the motor 3 or between the motor 3 and the automatic transmission 4 to reduce torque pulsation of the engine 2 . Further, a starting clutch that interrupts transmission of torque between the engine 2 and the motor 3 may be provided.

The engine 2 is an internal combustion engine such as a gasoline engine or a diesel engine, and the throttle opening and fuel injection amount are controlled according to the required driving force such as the depression amount (accelerator opening) of an accelerator pedal (not shown). It is configured to output a torque corresponding to the required driving force. Also, the engine 2 can be idled while the supply of fuel is stopped (fuel cut: F/C). In this case, braking force (engine braking force) is generated due to power loss due to pumping loss or the like. The motor 3 is a motor (motor generator: MG) such as a permanent magnet type synchronous motor that has a power generation function.

In addition, the automatic transmission 4 includes a plurality of engagement mechanisms such as clutches and brakes, and can set a plurality of forward gears and reverse gears according to the engagement and disengagement states of these engagement mechanisms. automatic transmission. FIG. 2 is a skeleton diagram of an automatic transmission with 10 forward speeds that can be employed as an embodiment of the present invention.

The automatic transmission 4 includes a Ravigneaux-type first planetary gear mechanism 6, a single-pinion-type second planetary gear mechanism 7, and a single-pinion-type third planetary gear mechanism 8 as main gear mechanisms. The first planetary gear mechanism 6 includes two sun gears S61 and S62, a ring gear R6, a first pinion gear P61 that meshes with the sun gear S61 and the ring gear R6, and a second sun gear S62 that meshes with the first pinion gear P61. A carrier C6 holding a two-pinion gear P62 is provided as a rotating element that performs differential action with each other. A first brake B1 is provided to selectively fix the first sun gear S61.

The second planetary gear mechanism 7 and the third planetary gear mechanism 8 are arranged on the same axis as the first planetary gear mechanism 6, and the second planetary gear mechanism 7 includes a sun gear S7, a ring gear R7, and these gears. A sun gear S7 and a carrier C7 holding a pinion gear P7 meshing with the ring gear R7 are provided as rotating elements that perform a differential action with each other. Similarly, the third planetary gear mechanism 8 comprises a sun gear S8, a ring gear R8, and a carrier C8 holding a pinion gear P8 meshing with the sun gear S8 and ring gear R8. It is equipped as

The sun gear S7 of the second planetary gear mechanism 7 and the sun gear S8 of the third planetary gear mechanism 8 are integrated with each other. A connecting first clutch K1 is provided. A second clutch K2 is provided for selectively connecting the sun gears S7 and S8 integrated with each other and the second sun gear S62 in the first planetary gear mechanism 6. As shown in FIG. Further, a third clutch K3 is provided for selectively connecting the ring gear R7 of the second planetary gear mechanism 7 and the ring gear R6 of the first planetary gear mechanism 6. As shown in FIG. A second brake B2 for selectively stopping the rotation of the ring gear R7 of the second planetary gear mechanism 7 is provided.

A carrier C6 in the first planetary gear mechanism 6 and a carrier C8 in the third planetary gear mechanism 8 are connected to the input shaft 5 of the automatic transmission 4 and serve as input elements. Furthermore, the carrier C7 of the second planetary gear mechanism 7 serves as an output element. A fourth clutch K4 is provided for selectively connecting the carrier C7 of the second planetary gear mechanism 7 and the ring gear R8 of the third planetary gear mechanism 8, which are the output elements. When the fourth clutch K4 is engaged, the second planetary gear mechanism 7 and the third planetary gear mechanism 8 are integrated with each other without differential action by connecting the two rotating elements. and rotate.

Each of the clutches K1 to K4 and the brakes B1 and B2 is a frictional engagement mechanism that is engaged and released by hydraulic pressure, for example, so that its torque capacity (torque to be transmitted) can be changed continuously. is configured to

In the automatic transmission 4 shown in FIG. 2, 10 forward gears (1st to 10th) and 10 reverse gears (Rev) can be set by controlling the clutches K1 to K3 and the brakes B1 and B2. can. The control of engaging and disengaging these engagement mechanisms can be performed by a conventionally known hydraulic control device (not shown), and the hydraulic control device can be electrically controlled. The control is the same as conventionally known gear shift control. A shift is performed when the line defining the (shift line) is crossed. Therefore, the target gear stage is determined by the required driving force such as the degree of opening of the accelerator and the vehicle speed or the rotational speed of the rotating member corresponding thereto, and each engagement mechanism is engaged and released so as to set the target gear stage. . The gear shift control is not limited to the control of changing gear stages one by one. It is possible to perform control such as so-called multiple speed change that sets the gear stage.

In addition, a single gear mechanism that couples the input shaft 5 and the output shaft 9 of the automatic transmission 4 without interposing the first planetary gear mechanism 6, the second planetary gear mechanism 7, and the third planetary gear mechanism 8 so that torque can be transmitted. A pinion type fourth planetary gear mechanism 10 is provided on the same axis as the planetary gear mechanisms 6 , 7 , 8 . Specifically, the input shaft 5 of the automatic transmission mechanism 4 passes through each planetary gear mechanism 6, 7, 8 and extends to the output side of the third planetary gear mechanism 8, and the sun gear S10 is connected to the tip thereof. A ring gear R10 is arranged concentrically with the sun gear S10, and a carrier C10 holding a pinion gear P10 meshing with the sun gear S10 and the ring gear R10 so as to rotate and revolve is connected to the carrier C7 of the second planetary gear mechanism 7, It is connected to the output shaft 9 of the automatic transmission mechanism 4 . A third brake B3 is also provided for selectively fixing the ring gear R10.

Therefore, by engaging the third brake B3, the fourth planetary gear mechanism 10 functions as a speed reducer, and the input shaft 5 and the output shaft 9 are connected without intervening the planetary gear mechanisms 6, 7, 8. concatenate That is, the fourth planetary gear mechanism 10 constitutes a "bypass path" in the embodiment of this invention. Incidentally, when the third brake B3 is engaged, the automatic transmission 4 is brought into the neutral state.

In the example shown in FIG. 1, a rear differential gear 12 is connected to the output shaft 9 of the automatic transmission 4 via a rear propeller shaft 11. From the rear differential gear 12, left and right rear wheels, which are drive wheels, are connected. A drive torque is transmitted to 13 . A transfer 14 is provided on the output side of the automatic transmission 4 . The transfer 14 is a mechanism for transmitting part of the torque output from the automatic transmission 4 to the front wheels 15 to establish a four-wheel drive state. A front propeller shaft 16 is connected to a front differential gear 17 for transmitting driving force to left and right front wheels 15 .

A transfer 14 having a conventionally known structure can be adopted. For example, a so-called part-time type transfer comprising a gear train for transmitting torque to the front propeller shaft 16 and a clutch (not shown) for selectively interrupting the transmission of torque, or a differential between the rear wheels 13 and the front wheels 15 a full-time transfer that always transmits torque to the rear wheels 13 and front wheels 15 while permitting good. Further, the transfer 14 may be provided with a transmission section capable of switching the gear ratio between the output shaft 9 of the automatic transmission 4 and the propeller shaft 11 to two gear ratios, high and low.

The motor 3 is electrically connected to a power storage device (BATT) 18 such as a storage battery or a capacitor. Therefore, it is possible to cause the motor 3 to function as a motor using the power of the power storage device 18 or to charge the power storage device 18 with power generated by the motor 3 .

An electronic control unit (ECU) 19 for controlling the engine 2, the motor 3, the automatic transmission 4, the fourth planetary gear mechanism 10 (or the third brake B3), the transfer 14, etc. is provided. The ECU 19 is mainly composed of a microcomputer, performs calculations based on input data and pre-stored data, and outputs the results of the calculations as control command signals. Since the ECU 19 is for controlling the above-described devices such as the engine 2, it may be a control device that integrates an engine ECU, a motor ECU, an automatic transmission ECU, or the like, or each of these ECUs. It may be a higher control device that outputs a command signal to.

The ECU 19 receives the vehicle speed V, the degree of accelerator opening, the remaining amount of charge in the power storage device 18, the engine speed, the brake on/off signal, the speed of the input shaft 5, and the like. Also output as control command signals are a control signal for the motor 3, an opening signal for the electronic throttle valve in the engine 2, a gear position control signal, a control signal for the third brake B3, a control signal for the transfer (Tr) 14, and the like. .

The hybrid vehicle 1 configured as described above has an engine running mode in which torque is transmitted from the engine 2 or the engine 2 and the motor 3 to the rear wheels 13 and the front wheels 15, and a mode in which the supply of fuel to the engine 2 is stopped. At least two driving modes, ie, an EV driving mode in which torque is transmitted from the motor 3 to the rear wheels 13 and the front wheels 15 can be set.

In the engine running mode, in order to improve the fuel efficiency of the engine 2, the gear stage of the automatic transmission 4 is set in the same manner as conventionally known gear shift control. In other words, a shift map is prepared with parameters such as the required drive force based on the degree of accelerator opening and the vehicle speed, and the shift stage is determined based on the shift map. In that case, by releasing the third brake 3, transmission of torque between the engine 2 and the rear wheels 13 and the front wheels 15 via the fourth planetary gear mechanism 10 is interrupted, and the torque is transmitted via the automatic transmission 4. Torque is transmitted. Note that the engine driving mode includes braking driving in which engine braking is applied to the rear wheels 13 and 15 by rotating the engine 2 together, in addition to forward driving and reverse driving.

In the EV driving mode, the automatic transmission 4 is set to neutral and the third gear is set in order to reduce the number of gears that transmit torque between the motor 3 and the rear wheels 13 and the front wheels 15 compared to the engine driving mode. By engaging the brake B3, the motor 3, the rear wheels 13 and the front wheels 15 are connected via the fourth planetary gear mechanism 10 so that torque can be transmitted. In the EV driving mode, the motor 3 functions as a power generator in addition to forward driving and reverse driving. 3 includes braking driving in which braking torque is applied to the rear wheels 13 and front wheels 15 to generate braking force.

By configuring the drive device of the hybrid vehicle 1 as described above, the number of gears for transmitting torque between the motor 3 and the rear wheels 13 and the front wheels 15 can be reduced when the EV running mode is set and the vehicle runs. It is possible to reduce the energy loss caused by factors such as slippage that occurs in gears to transmit torque. That is, since the driving torque to be output by the motor 3 can be reduced when the EV traveling mode is set to drive the vehicle, the amount of electric power supplied to the motor 3 can be reduced. Similarly, when the EV traveling mode is set and the vehicle travels by braking, the braking torque to be output from the motor 3 can be increased, so the amount of energy regenerated by the motor 3 can be increased.

The bypass path in the embodiment of the present invention is not limited to the one provided with the fourth planetary gear mechanism 10 shown in FIG. It suffices if a path can be formed that allows torque transmission without intervening the constituent planetary gear mechanisms 6 , 7 , 8 . An example of this is shown in FIG. 3. In the example shown in FIG. 3, a drive gear 20 is connected to the input shaft 5 of the automatic transmission 4, and the drive gear 20 is connected to a driven gear 22 via an idler gear 21. . Similarly, a drive gear 23 is connected to the output shaft 9 of the automatic transmission 4 , and the drive gear 23 is connected to a driven gear 25 via an idler gear 24 . A bypass clutch K5 for selectively connecting the driven gears 22, 25 is provided. In the example shown in FIG. 3, similarly to the example shown in FIG. It is configured to form a speed reduction ratio at which the number of revolutions is higher than the number of revolutions.

3, the bypass clutch K5 is released and the automatic transmission 4 is set to a predetermined gear stage in the engine running mode, as in the example shown in FIG. , torque can be transmitted from the engine 2 to the rear wheels 13 and the front wheels 15 via the automatic transmission 4 . In the EV driving mode, by setting the automatic transmission 4 to neutral and engaging the bypass clutch K5, torque is transmitted between the motor 3 and the rear wheels 13 and front wheels 15 without going through the automatic transmission 4. can be linked together. Therefore, it is possible to reduce power consumption and increase power generation in the EV running mode.

1 hybrid vehicle 2 engine 3 motor 4 automatic transmission 5 input shaft 6, 7, 8, 10 planetary gear mechanism

Claims (1)

It has a plurality of planetary gear mechanisms, and is configured to set a predetermined gear ratio by connecting at least any two rotating elements of the plurality of planetary gear mechanisms or fixing any of the rotating elements. A drive device for a hybrid vehicle comprising: a transmission mechanism with a variable speed, and an engine and a motor having a power generation function connected to the input side of the transmission mechanism
A driving device for a hybrid vehicle, comprising a bypass path that connects an input shaft of the speed change mechanism and an output shaft of the speed change mechanism so that torque can be transmitted without the plurality of planetary gear mechanisms.

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