JP3651846B2 - Power transmission device for hybrid vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes an engine and an electric motor that also serves as a generator, and transmits the output torque to the transmission via a differential gear device, so that the driving force for driving either or both of the engine and the electric motor is achieved. The present invention relates to a power transmission device for a parallel hybrid vehicle.
[0002]
[Prior art]
A conventional power transmission device for a parallel hybrid vehicle is disclosed in Japanese Patent Laid-Open No. 10-304513.
In this system, the first shaft (ring gear) of the planetary gear mechanism constituting the differential gear device has an engine, the second shaft (sun gear) has an electric rotational drive source (generator / motor), and the third shaft ( Planetary carriers) are respectively connected to the transmission. Further, the first shaft and the second shaft are configured to be fastened by a fastening device (direct coupling clutch), and a one-way clutch is provided between the input shaft and the fixed body of the transmission.
[0003]
Another conventional power transmission device for a parallel hybrid vehicle is described in US Pat. No. 5,258,651.
In this case, the engine, the electric rotation drive source, and the transmission are similarly connected to the planetary gear mechanism, and the second shaft to which the electric rotation drive source of the planetary gear mechanism is connected is the first brake device and the one-way. It is connected to a fixed body (case) via a clutch, and a second fastening device is connected between the second shaft and the third shaft (planetary carrier).
[0004]
[Problems to be solved by the invention]
However, as described in detail later, in the first conventional example, when the vehicle starts, the electric rotational drive source operates as a generator and starts creeping with the generated torque as a reaction force. A drive source is required. In addition, torque assist is not possible when the electric rotational drive source is operated as an electric motor, and the starting drive force can only be relied on the engine torque. In addition, regeneration (charging) with an increased generator speed cannot be performed.
[0005]
In the second conventional example, since the brake device is controlled by slip control at the time of creep start, there is no particular problem, but torque assist by the electric motor after the brake device is engaged is not possible, and the generator is accelerated. It is the same that regeneration (charging) cannot be performed.
The present invention has been made by paying attention to such a conventional problem, and can perform creep start without requiring an electric rotational drive source to have a particularly large capacity, and thereafter can perform torque-assisted start by an electric motor, and An object of the present invention is to provide a power transmission device for a hybrid vehicle that can also perform regeneration with an increased generator speed.
[0006]
[Means for Solving the Problems]
For this reason, the invention according to claim 1
Engine,
An electric rotational drive source having both functions of a generator and an electric motor;
A transmission,
A differential gear device in which an output shaft of the engine is connected to a first shaft, an output shaft of the electric rotational drive source is connected to a second shaft, and the transmission is connected to a third shaft;
A first fastening device for intermittently connecting between the first shaft and the second shaft of the differential gear device;
A second fastening device for intermittently connecting between the electric rotational drive source and the second shaft of the differential gear device;
A third fastening device disposed between the second shaft and the fixed body of the differential gear device and capable of adjusting a fastening force from opening to fastening;
It is characterized by including.
[0007]
According to the invention of claim 1,
By switching the operation of the first fastening device, the second fastening device, and the third fastening device according to the operating conditions, it is possible to satisfactorily perform engine start, creep / start, acceleration / steady state, regeneration (charge) during deceleration, It is possible to assist the engine torque by driving the electric rotational drive source as an electric motor at the time of starting, and it is also possible to regenerate efficiently by increasing the speed of the electric rotational drive source that operates as a generator at the time of regeneration.
[0008]
The invention according to claim 2
A one-way clutch for preventing reverse rotation of the third shaft is provided between the third shaft and the fixed body.
According to the invention of claim 2,
During engine start (cranking), even when the reaction force from the drive wheels cannot be obtained, such as when the transmission is in neutral, the reverse rotation of the third shaft can be prevented and fixed reliably, so the start torque can be obtained reliably. The invention according to claim 3 is
When the vehicle starts, slip control is performed by adjusting the fastening force of the third fastening device, and the slip control is stopped and fastened when the vehicle speed exceeds a predetermined value.
[0009]
According to the invention of claim 3,
With the reaction force by the slip control of the third fastening device, it is possible to generate an appropriate driving torque in the transmission and perform a smooth creep start.
Further, since the power generation torque of the electric rotational drive source is not used unlike the first conventional example, it is not necessary to enlarge the electric rotational drive source.
[0010]
The invention according to claim 4
When starting the vehicle, the first fastening device is fastened, the second fastening device is opened, the third fastening device is fastened, and the electric rotational drive source is operated as an electric motor to assist engine torque. Features.
According to the invention of claim 4,
When the first fastening device is fastened, the torque of the engine and the motor is applied and transmitted to the first shaft of the differential gear device, and the second shaft is fixed by fastening of the third fastening device. The combined torque is amplified and output with the gear ratio when the first axis is the input side and the third axis is the output side. As a result, a powerful starting drive torque that is torque-assisted by the electric motor is obtained.
[0011]
The invention according to claim 5
The first fastening device is fastened, the second fastening device is opened, the third fastening device is fastened, the electrical rotational drive source is operated as a generator, and the rotational speed of the electrical rotational drive source is The speed is increased and regenerated.
According to the invention of claim 5,
By fastening the first fastening device, opening the second fastening device, and fastening the third fastening device, the gear ratio with the third shaft of the differential gear device as the input side and the first shaft as the output side, The rotational speed of the electrical rotational drive source that operates as a generator is increased, and regeneration (charging) can be performed efficiently.
[0012]
The invention according to claim 6
Regeneration is performed by increasing the rotational speed of the electrical rotation drive source only during regeneration when the remaining amount of the battery connected to the electrical rotation drive source is low.
According to the invention of claim 6,
Only at the time of regeneration when the remaining amount of the battery is low, it is possible to efficiently recover and quickly recover the remaining amount of battery by performing the above-mentioned accelerated regeneration, and at other times of regeneration, the first fastening device, the second The battery is prevented from being overcharged by performing normal regeneration by fastening the fastening device and rotating the first shaft, the second shaft, and the third shaft of the differential gear device at a constant speed.
[0013]
The invention according to claim 7
The differential gear device is a planetary gear mechanism, wherein the first shaft is a rotating shaft of a ring gear, the second shaft is a rotating shaft of a sun gear, and the third shaft is a rotating shaft of a planetary carrier. .
According to the invention of claim 7,
By using the planetary gear mechanism, a compact differential gear device having a large gear ratio range can be obtained, and each driving performance can be sufficiently enhanced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, in which an output side of an electric rotary drive source 2 acting as an engine 1, a generator, and an electric motor is a first on the input side of a differential gear device 3, respectively. The third shaft 33 on the output side of the differential gear device 3 is connected to the input side of the transmission 4 and the output side of the transmission 4 is connected to an unillustrated final reduction gear or the like. It is connected to the drive wheel 5 via
[0015]
The engine 1 is controlled by an ECU (Engine Control Unit) 6. The electric rotation drive source 2 is controlled by an M / G · CU (motor / generator control unit) 8 connected to the power storage device 7 and charges the power storage device 7 when operating as a generator. The transmission 4 is controlled by a TMCU (transmission control unit) 9.
[0016]
Further, as shown in FIG. 2, the differential gear device 3 includes a sun gear S, a plurality of planetary gears P meshing with the outer peripheral side thereof at equiangular intervals, a planetary carrier C that connects each planetary gear P, and a planetary gear. A planetary gear mechanism having a ring gear R meshing with the outside of the gear P, the ring gear R is connected to the output shaft of the engine 1 via the first shaft 31, and the sun gear S is electrically connected via the second shaft 32. The planetary carrier C is connected to the input side of the transmission 4 via the third shaft 33, and is connected to the output shaft of the rotational drive source 2.
[0017]
Further, as a fastening system according to the present invention, a first clutch (first fastening device) 11 that intermittently connects between the first shaft 31 and the second shaft 32, the electric rotation drive source 2, and the second shaft. A second clutch (second fastening device) 12 that connects and disconnects between the second shaft and a brake (third fastening device) 13 disposed between the second shaft and the case (fixed body) 34 of the transmission 4. Further, a one-way clutch 14 that prevents reverse rotation of the third shaft 33 is connected between the third shaft 33 and the case 34.
[0018]
The operation of the power transmission device according to the present invention configured as described above will be described in comparison with the first and second conventional examples.
First, the starting time will be described. FIG. 3A shows a functional block diagram at the time of starting. In the functional block diagram of FIG. 3 (A) and subsequent drawings, the black engagement element indicates the operation (engaged state: the one-way clutch 14 is fixed while preventing the reverse rotation of the third shaft 33). The element indicates a non-operation (non-engaged state: the one-way clutch 14 is allowing the third shaft 33 to rotate forward). The brake 13 is indicated by hatching when slip control is being performed.
[0019]
At the time of starting, the second clutch 12 is engaged, the first clutch 11 and the brake 13 are opened, and the electric rotational drive source 2 is driven as an electric motor. As a result, the sun gear S rotates through the second shaft 32. Here, since the third shaft 33, that is, the planetary carrier C, is prevented from being reversed and fixed by the one-way clutch 14, the ring gear R rotates through the idle rotation of the planetary gear P that functions as an idler. That is, the engine 1 is rotationally driven and cranked by the electrical rotational drive source 2 that operates as an electric motor.
[0020]
FIG. 3B is a lever diagram at the time of starting. Here, assuming that the gear ratio determined by the number of teeth ZR and Zs of the ring gear R and the sun gear S when the input side is the ring gear R and the output side is the sun gear S is γ (= Zs / Z <1), The output torque TM / G of the rotary drive source 2 is calculated as follows:
TE = (1 / γ) ・ TM / G (1)
That is, the input side connected to the electric rotational drive source 2 is the sun gear S, the output side connected to the engine 1 is the ring gear R, and the engine 1 is driven with the torque TE amplified by the gear ratio 1 / γ. .
[0021]
It should be noted that since the first and second conventional examples function in the same manner at the time of starting, the description thereof is omitted.
Next, the creep start time will be described.
First, the case of the first conventional example will be described with reference to FIGS. In this device, the engine E, the electric rotational drive source M / G, and the transmission AT are connected to the first to third shafts of the differential gear device as in the present embodiment. Also, the clutch that connects and disconnects the first shaft and the second shaft of the differential gear device and the one-way clutch that is connected between the third shaft and the case (fixed body) are the same as in the present embodiment. is there. Further, a one-way clutch that allows transmission of only the driving force from the electric rotational drive source M / G to the engine E is connected in parallel with the clutch.
[0022]
At the time of creep start, as shown in FIG. 4C, all the fastening elements are deactivated, the motor / generator is operated as a generator in the engine driving state, and the generated torque TM / G is set to the engine torque TE. It starts by generating as a reaction force.
FIG. 4D is a lever diagram at the time of creep start, and the drive torque TAT of the transmission is obtained as follows.
[0023]
TAT = {(1 + γ) / γ} · TM / G (2)
In this system, when the engine torque TE is increased as the starting drive force, a large power generation torque TM / G is required as a reaction force, and a large capacity motor / generator is required.
Next, the operation | movement at the time of the creep start of this embodiment is demonstrated. When creeping or starting, as shown in FIG. 4A, the first clutch 11 is engaged, the second clutch 12 is released, and the engine 13 is driven while the brake 13 is slip-controlled (slid in a semi-engaged state). To do. Accordingly, the planetary carrier C is rotated by the reaction force of the brake 13 applied to the sun gear S, and the transmission 4 is driven via the third shaft 33 to start creeping.
[0024]
Referring to the lever diagram of FIG. 4B, if the brake torque applied to the sun gear S is TB, the drive torque TAT of the transmission 4 is calculated as follows:
TAT = {(1 + γ) / γ} · TB (3)
That is, when the input side receiving the brake torque TB as a reaction force is the sun gear S and the output side connected to the transmission 4 is the planetary carrier C, the drive torque TAT amplified by the gear ratio (1 + γ) / γ is obtained.
[0025]
In this system, since the electric rotation drive source 2 starts without using it as a generator, the capacity of the electric rotation drive source 2 is not affected by the engine torque TE as the start drive force. It is not necessary to enlarge 2 specially. It is possible to assist the engine torque by driving the electric rotational drive source 2 as an electric motor.
[0026]
Since the second conventional example functions in the same manner as the present invention at the start of creep, the description thereof is omitted.
When the vehicle starts with the creep start and the vehicle speed reaches a predetermined value or higher, the vehicle is switched to a start with the brake 13 fully engaged.
At the time of starting, the transmission 4 is driven by amplifying the engine torque TE with a gear ratio (1 + γ) as shown below using the ring gear R to which the engine torque TE is input as the input side and the planetary carrier C as the output side. Torque TAT is obtained.
[0027]
TAT = (1 + γ) · TE (4)
And in this embodiment, as shown to FIG. 5 (A), the said 1st clutch 11 is act | operated in said state, the 1st axis | shaft 31 and the 2nd axis | shaft 32 are fastened, and the electric rotational drive source 2 is set. When driven as an electric motor, the driving torque TM / G of the electric motor can assist the engine torque TE and further increase the driving torque TAT of the transmission 4.
[0028]
That is, as shown in the lever diagram of FIG. 5B, when the torque TR acting on the ring gear R is used, the drive torque TAT of the transmission 4 is calculated by the following equation.
TAT = (1 + γ) ・ TR
TR = TE + TM / G
∴TAT = (1 + γ) ・ (TE + TM / G) (5)
Compared with the conventional example, in the first conventional example, when the engine torque TE is completely supported by using the power generation torque TM / G as a reaction force in the equation (2) at the time of the creep start, TM / G = TE / As γ, the drive torque TAT of the transmission is calculated as in the following equation as in the equation (4).
[0029]
TAT = (1 + γ) · TE (6)
However, since the electric rotational drive source 2 is used as a generator to support the reaction force of the engine torque TE as described above when starting, it cannot be driven as an electric motor and cannot be assisted by the driving torque of the electric motor. .
Next, it compares with the 2nd prior art example. As shown in the functional block diagram of FIG. 5C, in the second conventional example, the engine E, the electrical rotation drive source M / G, and the transmission AT are the same as the first embodiment of the differential gear device. The shaft is connected to the third shaft. Further, the second shaft and the third shaft of the differential gear device are connected by a clutch, and the second shaft is connected to the case (fixed body) via a one-way clutch having a function of preventing reverse rotation of the brake and the second shaft. It is connected.
[0030]
When the creep starts, the brake is slip-controlled, and when the brake is completely engaged, a transmission drive torque TAT obtained by amplifying the engine torque TE with a gear ratio (1 + γ) is obtained.
However, in this case as well, only the driving torque TAT that makes the most of the engine torque TE can be obtained by fixing the third shaft at the time of starting, and the electric rotational driving source M / G is driven as an electric motor to assist. It is not possible.
[0031]
Next, as described above in the present embodiment, during steady operation / acceleration after starting with the drive torque TAT amplified using the differential gear device 3, as shown in the functional block diagram of FIG. In addition, both the first clutch 11 and the second clutch 12 are engaged, and the brake 13 is released. That is, since a driving torque TAT that is as great as when starting is not required, torque amplification by the differential gear device 3 is not performed, and the sun gear S, the planetary gear P, and the ring gear R are not relatively rotated, and the first shaft, The shaft and the third shaft are integrally rotated at a constant speed.
[0032]
FIG. 6B shows a lever diagram, and the driving torque TAT is calculated as follows.
TAT = TE (when only the engine is driven) or TE + TM / G (when the engine and motor are driven) (7)
The same applies to the first and second conventional examples during the steady state and acceleration.
[0033]
Next, the time of deceleration will be described. At the time of deceleration, the electric rotational drive source M / G operates as a generator to perform regeneration (charging). In the present embodiment, two types of regeneration, constant speed regeneration and increased regeneration, are possible as follows.
At the time of deceleration when the remaining amount of the battery is above a predetermined level, constant speed regeneration is performed as follows.
[0034]
As shown in FIG. 7 (A), for each engagement element, the first clutch 11 and the second clutch 12 are both engaged, the brake 13 is released, and the differential gear device 3 The first shaft, the second shaft, and the third shaft rotate together at a constant speed, but the engine 1 generates a negative engine torque TE due to the engine braking action, and operates as an electric rotational drive source M / G as a generator. Negative torque TM / G.
[0035]
FIG. 7B shows a lever diagram, and the relationship between the torque TAT of the transmission 4 and the engine torque TE, and the torque TM / G of the electric rotational drive source 2 is shown in the same manner as the equation (7). An engine 1 and an electric rotational drive source 2 as a generator are driven by torque TAT from the drive wheel side.
About the said equal speed regeneration, the 1st, 2nd prior art example is performed similarly.
[0036]
When the remaining battery level is insufficient, speed-up regeneration is performed as follows.
As shown in FIG. 8A, the first clutch 11 is engaged, the second clutch 12 is released, and the brake 13 is engaged. The negative engine torque TE is generated by the deceleration operation, and the electric rotational drive source 2 operating as a generator generates the negative torque TM / G, similar to the constant speed regeneration.
[0037]
FIG. 8B shows a lever diagram. The relationship between the torque TAT of the transmission, the engine torque TE, and the torque TM / G of the electric rotational drive source M / G is expressed by the following equation.
TAT = (1 + γ) ・ (TE + TM / G) (8)
This relationship is the same as the equation (5) at the time of starting, but since it is during regeneration, the load torque TM / G of the electric rotary drive source 2 driven as a generator by the torque TAT from the drive wheel side is Compared with the constant speed regeneration, it is reduced to 1 / (1 + γ), indicating that the rotational speed of the electrical rotary drive source 2 is increased by (1 + γ) times.
[0038]
As described above, when the remaining amount of the battery is insufficient, by performing the above-mentioned speed-up regeneration, the electric rotation drive source 2 can be speeded up and the regeneration can be performed efficiently, and the speed-up regeneration is always performed. Therefore, it is possible to reduce the frequency of occurrence of torque shocks when switching control to acceleration regeneration.
In the first conventional example and the second conventional example, since the first clutch and the brake of the present embodiment are not provided at the same time, the above-mentioned speed regeneration cannot be performed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.
FIG. 2 is a block diagram showing a system configuration of the embodiment.
FIG. 3 is a functional block diagram and a lever diagram at the start of the embodiment.
FIG. 4 is a functional block diagram and lever diagram at the time of creep start of the embodiment and the first conventional example.
FIG. 5 is a functional block diagram and lever diagram at the start of the embodiment and the second conventional example.
FIG. 6 is a functional block diagram and lever diagram at the time of acceleration and steady state of the embodiment.
FIG. 7 is a functional block diagram and lever diagram during constant speed regeneration according to the embodiment.
FIG. 8 is a functional block diagram and a lever diagram at the time of speed increase regeneration according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine 2 Electric rotation drive source 3 Differential gear apparatus 4 Transmission 11 First clutch 12 Second clutch 13 Brake 31 First shaft 32 Second shaft 33 Third shaft 34 One-way clutch

Claims (7)

Engine,
An electric rotational drive source having both functions of a generator and an electric motor;
A transmission,
A differential gear device in which an output shaft of the engine is connected to a first shaft, an output shaft of the electric rotational drive source is connected to a second shaft, and the transmission is connected to a third shaft;
A first fastening device for intermittently connecting between the first shaft and the second shaft of the differential gear device;
A second fastening device for intermittently connecting between the electric rotational drive source and the second shaft of the differential gear device;
A third fastening device disposed between the second shaft and the fixed body of the differential gear device and capable of adjusting a fastening force from opening to fastening;
A power transmission device for a hybrid vehicle, comprising: The power transmission device for a hybrid vehicle according to claim 1, further comprising a one-way clutch that prevents reverse rotation of the third shaft between the third shaft and the fixed body. 3. The hybrid vehicle according to claim 1, wherein when the vehicle starts, slip control is performed by adjusting a fastening force of the third fastening device, and the slip control is stopped and fastened when the vehicle speed exceeds a predetermined vehicle speed. Power transmission device. When starting the vehicle, the first fastening device is fastened, the second fastening device is opened, the third fastening device is fastened, and the electric rotational drive source is operated as an electric motor to assist engine torque. The power transmission apparatus for a hybrid vehicle according to any one of claims 1 to 3. The first fastening device is fastened, the second fastening device is opened, the third fastening device is fastened, the electrical rotational drive source is operated as a generator, and the rotational speed of the electrical rotational drive source is 5. The power transmission device for a hybrid vehicle according to claim 1, wherein the power transmission device is regenerated at a higher speed. The regenerative operation is performed by increasing the rotational speed of the electrical rotation drive source only during regeneration when the remaining amount of the battery connected to the electrical rotation drive source is low. A power transmission device for a hybrid vehicle. The differential gear device is a planetary gear mechanism, wherein the first shaft is a rotating shaft of a ring gear, the second shaft is a rotating shaft of a sun gear, and the third shaft is a rotating shaft of a planetary carrier. The power transmission apparatus of the hybrid vehicle as described in any one of Claims 1-6.

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