JP3306985B2 - Driving force control device for electric vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force control device for an electric vehicle, and more particularly to an electric vehicle equipped with a clutch for interrupting power transmission when a shift lever is operated to a neutral range. This relates to driving force control when the lever is returned from the neutral range to the traveling range.

[0002]

2. Description of the Related Art Generally, an electric vehicle includes: (a) a shift lever selectively operated to a plurality of ranges including a neutral range and a traveling range; and (b) selection range detecting means for detecting a selection range of the shift lever. (C) an accelerator operation amount detecting means for detecting an accelerator operation amount; (d) an electric motor for rotating driving wheels; and (e) an accelerator operation when the shift lever is selectively operated to the travel range. Torque control means for controlling the torque of the electric motor according to the amount. Conventionally, in such an electric vehicle, a series of power transmission paths from a motor shaft of an electric motor to driving wheels are in a directly connected state,
For example, if the electric motor breaks down and locks, there is a problem that the driving wheels are also locked and it becomes difficult to move the vehicle.

On the other hand, in the Japanese Patent Application No. 4-257136 previously filed by the present applicant, (f) a clutch for connecting and disconnecting the power transmission between the electric motor and the drive wheels, and (g) Switching means for setting the clutch to a connected state when the shift lever is selectively operated to the travel range and disengaging the clutch when the shift lever is operated to the neutral range; We have proposed an electric vehicle that can shut off power transmission between the electric motor and the drive wheels by operating in the neutral range. In an electric vehicle equipped with such a clutch, coasting can be performed by shifting to a neutral range while the vehicle is running. However, when the shift operation is performed again to a driving range such as a D (drive) range, the electric vehicle is shifted to a neutral range. However, if there is a large rotational speed difference between the engagement elements of the clutch, the load on the clutch is large and the time required for engagement is long, so that when the clutch is in the disconnected state, the engagement elements of the clutch are substantially The electric motor is synchronously controlled so as to have the same rotation speed.

[0004]

However, even in such an electric vehicle, when the shift lever is shifted from the neutral range to the travel range, the electric motor is immediately controlled by the torque control means according to the accelerator operation amount. Therefore, if the driver performs a shift operation while depressing the accelerator, the motor torque will increase before the clutch is completely engaged, causing a significant burden on the clutch and significantly shortening the life of the clutch. there were.

The present invention has been made in view of the above circumstances, and has as its object to arrange between an electric motor and drive wheels to switch between a connected state and a disconnected state according to a shift lever operation. To improve the life of the clutch.

[0006]

In order to achieve this object, when the shift lever is operated to switch from the neutral range to the travel range, torque control according to the accelerator operation amount until the clutch is fully engaged. As shown in the claim correspondence diagram of FIG. 1, the present invention provides (a) a shift lever selectively operated to a plurality of ranges including a neutral range and a travel range, and (b) a shift lever thereof. A selection range detection means for detecting a selection range of the lever, (c) an accelerator operation amount detection means for detecting an accelerator operation amount, and (d) an electric motor for rotatingly driving a drive wheel;
(E) a driving force control device for an electric vehicle, comprising: torque control means for controlling torque of the electric motor in accordance with the accelerator operation amount when the shift lever is selectively operated to the travel range. A) a clutch for connecting and disconnecting power transmission between the electric motor and the drive wheels;
(G) a switching means for the shift lever is in the connected state of the clutch when the selected operation to the running range, to the clutch cut-off state when the shift lever is operated to said neutral range, (h ) The shift lever
Is operated to the neutral range, the clutch
The electric motor is driven so that the engagement elements have substantially the same rotational speed.
Synchronous control means for synchronously controlling the motor; and ( i ) when the shift lever is operated to switch from the neutral range to the travel range, until the engagement element of the clutch is considered to be completely engaged. And delay means for delaying torque control of the electric motor by the torque control means. In FIG. 1, the synchronization control means is omitted.

[0007]

In such a driving force control device for an electric vehicle, when the shift lever is operated to the neutral range, the clutch is disengaged via the switching means, and the electric motor and the driving wheels are disconnected. Power transmission is interrupted. Therefore, when the electric motor is out of order and locked, the vehicle can be easily moved by operating the shift lever to the neutral range to separate the electric motor from the drive wheels, and the electric motor may be abnormally locked. Even in the case of rotation, if the shift lever is operated to the neutral range, the electric motor and the drive wheels are disconnected, so that the traveling abnormality of the vehicle due to the abnormal rotation of the electric motor can be easily avoided. Further, since power transmission can be interrupted by the clutch in this manner, coasting can be performed by operating the shift lever to the neutral range while the vehicle is traveling, and the degree of freedom in driving operation of the electric vehicle is increased. And the shift lever is medium
When operated to the vertical range, the clutch engagement elements
The electric motor is controlled synchronously so that
The shift lever from the neutral range to the drive range.
When returning, the clutch is connected smoothly and the clutch
The burden on
A clutch can be employed.

On the other hand, when the shift lever is operated to switch from the neutral range to the traveling range, until the engagement element of the clutch is deemed to be completely engaged, it is determined according to the accelerator operation amount by the torque control means. The torque control of the electric motor is delayed by the delay means. Therefore, for example, even when the driver shifts the shift lever to the travel range while stepping on the accelerator after performing coasting in the neutral range, even when the clutch connection is incomplete, the motor torque is determined according to the accelerator operation amount. Is avoided, the load on the clutch is reduced, the life is improved, and a small clutch can be adopted.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a skeleton view showing a drive system of the electric vehicle according to the present embodiment. The motor shaft 12 of the electric motor 10 is connected to a small gear 16 via a clutch 14 and the small gear 16 Are meshed with a large gear 20 provided on the intermediate shaft 18. A small gear 22 is provided on the intermediate shaft 18 separately from the large gear 20.
It meshes with a large gear 26 provided on the output shaft 24. Due to the meshing of these gears 16, 20, 22, 26, the rotation of the electric motor 10 is controlled at a predetermined constant reduction ratio i (= rotation speed Nin of the small gear 16 / rotation speed Nout of the output shaft 24). The transmission is decelerated and transmitted to the output shaft 24, and further transmitted to a pair of drive wheels via a differential device (not shown). Reduction gear 2 including gears 16, 20, 22, 26
8 are configured. As the electric motor 10, various motors such as a permanent magnet type AC motor, an induction motor, a synchronous motor, and a DC motor can be used.

As shown in detail in FIG. 3, the clutch 14 includes a clutch hub 30 spline-fitted to the motor shaft 12 and a sleeve 32 spline-fitted to the outer periphery of the clutch hub 30. A plurality of shifting keys 34 fitted into a plurality of grooves formed in the outer peripheral portion of the clutch hub 30 and pressed against the inner peripheral surface of the sleeve 32 by a spring; And a tapered part 38 integrally provided with the clutch gear 36.
And a synchronizer ring 40 which is rotatably fitted to the outer peripheral portion of the small gear 16. The clutch gear 36 is splined with the small gear 16 which is relatively rotatably disposed on the motor shaft 12 via a bearing 42. Mated.
Then, as shown in FIG.
0, the power transmission between the motor shaft 12 and the small gear 16 is cut off, while the sleeve 32 is moved to the left in the drawing, and the clutch hub 30
In the connected state in which the clutch gear 36 straddles and meshes, power transmission between the motor shaft 12 and the small gear 16 is allowed. When switching from the disconnection state to the connection state, the friction between the synchronizer ring 40 and the tapered portion 38 causes the clutch gear 36 and the motor shaft 12 to rotate synchronously. Even when there is a rotation difference, the engagement of the sleeve 32 with the clutch gear 36 is performed relatively smoothly.

An annular groove 44 is formed on the outer peripheral surface of the sleeve 32.
And the shift fork 46 is engaged so as to be relatively rotatable. The shift fork 46 is connected to the motor shaft 12.
The sleeve 32 is moved in the left-right direction in the figure by moving the shift rod 48 in the axial direction. Is switched. The shift rod 48 is supported by the housing 50 so as to be movable in the axial direction.
2, it is urged leftward in the figure, that is, in a direction approaching the parking lock rod 54.

The parking lock rod 54 is disposed in a direction perpendicular to the axis of the shift rod 48, specifically, in the vertical direction in the figure, and is movable in the axial direction. 56. The lever 56 is connected to a shift lever 60 via a cable 58. When the shift lever 60 is switched between "P (parking)", "R (reverse)", "N (neutral)" and "D (drive)". The parking lock rod 54 is moved up and down in the figure by selecting and operating each range. The P range is an operation range when the vehicle is parked and stopped, the R range is an operation range when the vehicle is moved backward, and the N range is an operation range when the power transmission between the electric motor 10 and the driving wheels is shut off. In the operating range,
The D range is an operation range for moving the vehicle forward,
The R and D ranges correspond to the driving range, and the N range corresponds to the neutral range.

A shift cam 62 is provided at an intermediate portion of the parking lock rod 54, and is engaged with a cam roller 64 provided at the left end of the shift rod 48 when the shift lever 60 is operated to the N range. Then, the shift rod 48 is moved rightward in the figure against the urging force of the spring 52. Thereby, the sleeve 3
2 is also moved rightward, the engagement with the clutch gear 36 is released, and the clutch 14 is brought into a disconnected state. FIG.
This is the case where the shift lever 60 is operated to the N range and the clutch 14 is disengaged. on the other hand,
When the shift lever 60 is operated to a position other than the N range, that is, to the D, R, or P range, the shift cam 6
The engagement between the cam roller 64 and the cam roller 64 is released, the shift rod 48 is moved leftward in the figure according to the urging force of the spring 52, and the clutch 14 is brought into the connected state. In this embodiment, the shift fork 46, shift rod 48, spring 52, parking lock rod 54, lever 56,
Cable 58, shift cam 62, and cam roller 64
Thus, a switching means 66 for switching the clutch 14 according to the selection range of the shift lever 60 is configured.

The parking lock rod 54 also has a lock cam 68 at the lower end as shown in FIG.
Is provided. The lock cam 68 rotates the parking lock pole 70 clockwise against the urging force of the torsion coil spring 72 when the shift lever 60 is operated to the P range and the parking lock rod 54 is moved upward. The rotation of the motor shaft 12 is mechanically prevented by engaging with a parking lock gear 74 provided on the motor shaft 12. In the P range, since the clutch 14 is in the connected state, the motor shaft 12
The rotation of the drive wheels is also prevented by preventing the rotation of the drive wheels.

FIG. 5 is a block diagram for explaining a control system provided in the electric vehicle of this embodiment. The electric motor 10 is supplied with driving power from a power source 90 such as a battery via a motor driving control circuit 92. As a result, it is driven to rotate in both forward and reverse directions. The motor drive control circuit 92 is an inverter or the like. The motor drive control circuit 92 controls the torque of the electric motor 10 by changing the frequency or current of the drive power in accordance with a command signal ST supplied from the motor control computer 94. Performs regenerative braking that accumulates in the power supply 90 electric energy generated by forced rotation of the power supply. The motor control computer 94 has a CP
U96, RAM 98, ROM 100, clock signal source 102 such as crystal oscillator, A / D converter (not shown), input / output interface circuit, etc.
8, the signal processing is performed in accordance with a program stored in the ROM 100 in advance while using the temporary storage function of 8 and the command signal ST is output to the motor drive control circuit 92 to control the output torque and the regenerative braking torque of the electric motor 10. .

The motor control computer 94 includes:
A motor rotation speed sensor 78, a vehicle speed sensor 82, a shift position sensor 84, an accelerator operation amount sensor 86, a limit switch 88, and the like are connected, a motor rotation speed signal SNm representing a rotation speed Nm of the motor shaft 12, and a rotation speed of the output shaft 24. Nout, an output shaft rotation speed signal SNout, a shift position signal SSh representing a selection range of the shift lever 60, an accelerator operation amount signal SAc representing an accelerator pedal operation amount Ac, and a connection state in which the clutch 14 is completely engaged. And the like are respectively supplied. The motor rotation speed sensor 78 detects the motor rotation speed Nm by distinguishing between forward rotation of the vehicle moving forward and reverse rotation of the vehicle moving backward. For example, the motor rotation speed sensor 78 outputs a pair of pulse signals having different phases in forward and reverse rotation. Is output. A limit switch 88 is disposed near the shift rod 48, and the shift rod 48 is moved leftward in FIG. 3 so that the sleeve 32 straddles and engages with the clutch hub 30 and the clutch gear 36. When the shift rod 4
8, the clutch engagement signal SC is switched between ON and OFF. The shift position sensor 84 corresponds to selection range detection means, and the accelerator operation amount sensor 86 corresponds to accelerator operation amount detection means.

The motor control computer 94 controls the torque of the electric motor 10 according to the flowchart shown in FIG. This flowchart is repeatedly executed, for example, with a cycle time of about several tens msec. First, in step S1, the shift position signal SS
Based on h, it is determined whether or not the selection range of the shift lever 60 is the N range, in other words, whether or not the clutch 14 is in the disengaged state. If the selection range is the N range, step S2 and subsequent steps are executed. Step S4 and subsequent steps are executed. The step S2 executed in the case of the N range includes an engagement element of the clutch 14, ie, an engagement element of the clutch 14, so that a large load is not applied to the clutch 14 when the shift lever 60 is returned to the D or R travel range while the vehicle is traveling. The synchronous control of the electric motor 10 is performed so that the sleeve 32 and the clutch gear 36 spline-fitted to the clutch hub 30 have substantially the same rotational speed. In the next step S3, the flag F1 is set to "1".

The synchronization control in step S2 is performed according to the flowchart shown in FIG. 7. In step R1, a motor rotation speed signal SNm and an output shaft rotation speed signal SNout are set.
Motor speed Nm and output shaft speed N based on
out is read, and in step R2, the input rotation speed Nin is calculated by multiplying the reduction ratio i of the speed reducer 28 by the output shaft rotation speed Nout. This input rotation speed Nin
Is the rotation speed of the input member of the speed reducer 28, that is, the small gear 16. In a succeeding step R3, a rotation speed difference No = Nm-N between the motor rotation speed Nm and the input rotation speed Nin.
in is calculated, and in step R4, the rotational speed difference N
It is determined whether or not the absolute value | No | of o is equal to or greater than a predetermined determination value a. The judgment value a is for judging whether or not the rotation speed difference | No | is small enough to enable the clutch 14 to be smoothly connected. When | No | <a, the current motor rotation speed Nm is used. Is not necessary, the current target torque To is maintained in step R7, and the command signal ST representing the target torque To is output to the motor drive control circuit 92, so that the torque of the electric motor 10 is reduced to the target torque To. Is controlled so as to approximately match.

If the determination in step R4 is YES,
That is, when the rotation speed difference | No | is equal to or greater than the determination value a, it is desirable to change the rotation speed of the electric motor 10 in order to ensure that the clutch 14 is smoothly connected. Is calculated. The torque correction value ΔT is obtained by, for example, a data map or an arithmetic expression as shown in FIG. 9 stored in advance in the ROM 100 or the like using the rotational speed difference | No | as a parameter. In the next step R6, it is determined whether or not the rotation speed difference No is positive. If the rotation speed difference No is positive, that is, if the motor rotation speed Nm is larger than the input rotation speed Nin, the motor rotation speed Nm is determined. In order to reduce the torque of the electric motor 10 by subtracting the torque correction value ΔT from the current target torque To to obtain a new target torque To in step R8 and outputting a command signal ST representing the target torque To. Is reduced by the torque correction value ΔT. Also, the rotational speed difference N
When o is negative, that is, when the motor rotation speed Nm is smaller than the input rotation speed Nin, in order to increase the motor rotation speed Nm, the current target torque To is increased in step R9.
Is added to the torque correction value ΔT to obtain a new target torque To, and by outputting a command signal ST representing the target torque To, the torque of the electric motor 10 is increased by the torque correction value ΔT. By performing the torque control of the electric motor 10 in this manner, the motor rotation speed Nm is made substantially equal to the input rotation speed Nin, and the sleeve 32 of the clutch 14 is rotated at substantially the same rotation speed as the clutch gear 36. Become.

Returning to FIG. 6, when the determination in step S1 is NO, that is, when the selection range of the shift lever 60 is not the N range, step S4 is executed to determine whether the flag F1 is "1". . Since the flag F1 is set to "1" in step S3 in the case of the N range,
Immediately after the shift lever 60 is switched from the N range, F1 = 1 and step S5 is executed. In step S5, based on the clutch engagement signal SC supplied from the limit switch 88, it is determined whether or not the clutch 14 is in the fully engaged connection state. The target torque To, in other words, the last target torque To in the synchronous control in step S2 is maintained. However, if the clutch 14 is completely engaged, the flag F1 is set to "0" in step S6, and the process proceeds to step S7. Performs normal torque control.
By setting the flag F1 = 0, in the subsequent cycle, the normal torque control of step S7 is performed immediately after step S4.

The normal torque control in step S7 is as follows.
In accordance with the selection range of the shift lever 60, the electric motor 10 is controlled based on the accelerator operation amount Ac and the motor rotation speed Nm.
For example, in the case of the D range, in the case of the D range, the electric motor 10 is rotationally driven in a forward rotation direction in which the vehicle moves forward, and according to a data map as shown in FIG. A torque control value Ta is calculated based on the accelerator operation amount Ac and the motor rotation speed Nm, and the torque control value Ta is set to the target torque T.
By outputting the command signal ST as “o”, the control is performed such that the torque of the electric motor 10 matches the target torque To, ie, the torque control value Ta. Further, when a predetermined braking condition is satisfied, such as when the brake is depressed at a predetermined vehicle speed or higher, a command signal ST for generating regenerative braking torque is output, and the engine braking in the automobile of the internal combustion engine is performed. Generates the same braking torque as
In addition to controlling the magnitude, the electric power corresponding to the braking torque is stored in the power supply 90. In the case of the R range, the electric motor 10 is driven to rotate in the reverse rotation direction in which the vehicle moves backward, and the torque is controlled based on the accelerator operation amount Ac and the motor rotation speed Nm as in the case of the D range. In the case of the P range, the target torque To is set to 0, and the motor output is set to 0.

Here, when the shift operation is performed from the N range to the D range while the vehicle is running, the target torque To during the synchronous control is maintained in step S8 until the clutch 14 is completely engaged, regardless of the accelerator operation. Therefore, when the process returns to the normal torque control in step S7, the motor torque may suddenly increase, causing a shock. Therefore, for example, it is desirable to control the torque to be gradually increased as shown in FIG. That is, after calculating the torque control value Ta based on the accelerator operation amount Ac and the motor rotation speed Nm from the data map as shown in FIG. 10 in step Q1, in step Q2, the current target torque To is set to a predetermined constant value. It is determined whether or not the torque control value Ta is smaller than the value (To + α) obtained by adding the value α, and Ta <(T
o + α), the torque control value Ta is immediately set to the target torque To in step Q3, but (To + α) ≦ Ta
In step Q4, the target torque To is set to a constant value α
Just make it bigger. The constant value α is a torque increase width of the electric motor 10 that can be changed while preventing a shock. Accordingly, even when the torque control value Ta calculated in step Q1 in accordance with the accelerator operation amount Ac is large, the electric motor The torque of the motor 10 is smoothly increased to approach the torque control value Ta. It is desirable to perform the same control when operated to the R range.

As described above, in the electric vehicle of this embodiment, when the shift lever 60 is operated to the N range, the clutch 14
Is in a cutoff state, and the power transmission between the electric motor 10 and the speed reducer 28 is cut off. Therefore, when the electric motor 10 is locked due to a failure, the shift lever 60 is operated to the N range to move the electric motor. By separating 10 from the wheels, the vehicle can be easily moved. Even when the electric motor 10 causes abnormal rotation such as reverse rotation due to an abnormality in the motor control system or the like, the abnormal rotation of the electric motor 10 can be achieved by operating the shift lever 60 to the N range to separate the electric motor 10 from the wheels. Therefore, it is possible to easily avoid the traveling abnormality of the vehicle due to the above. In particular, the clutch 14 is mechanically connected to the shift lever 60 via the switching means 66,
Since the connection state and the disconnection state can be reliably switched in accordance with the operation of the shift lever 60, the electric motor can be reliably switched even when the electric system is abnormal, for example, as compared with the case where the switching is performed using an electric actuator or the like. 10 and the wheel can be separated.

Since the power transmission can be cut off by the clutch 14 as described above, the coasting can be performed by operating the shift lever 60 to the N range while the vehicle is running, and the driving operation of the electric vehicle can be freely performed. The degree increases. Moreover, in this embodiment, when the shift lever 60 is operated to the N range, the motor rotation speed Nm is changed to the input rotation speed Nin according to the vehicle speed, that is, the output shaft rotation speed Nout.
When the shift lever 60 is returned from the N range to the D range or the R range, the clutch 14 is smoothly connected, and the load applied to the clutch 14 is controlled. And the life is improved, and a small clutch can be employed.

FIG. 11 shows the state of the shift lever 60 while the vehicle is running.
Is an example of a time chart showing changes in the motor rotation speed Nm and the output shaft rotation speed Nout when the "D" range is operated from the "D" range to the "N" range and thereafter returned to the "D" range. In FIG. 11, the solid line is a downward slope, and the vehicle speed, that is, the output shaft rotation speed Nout increases in the N range. The dashed-dotted line is a flat ground or an upward slope, and the vehicle speed, that is, the output shaft rotation speed Nout decreases in the N range. In any case, since the torque control of the electric motor 10 is performed in accordance with the output shaft rotation speed Nout such that the motor rotation speed Nm substantially matches the input rotation speed Nin, the shift from the N range to the D range is performed. When returning the lever 60, the clutch 14 is smoothly switched from the disengaged state to the connected state.

On the other hand, in this embodiment, the shift lever 60
When the operation is switched from the range to another range, the normal torque control according to the accelerator operation amount Ac is not performed until the clutch 14 is completely engaged. Even when the driver shifts the shift lever 60 to the D range or the R range while depressing the accelerator, it is possible to prevent the motor torque from being increased in accordance with the accelerator operation amount Ac when the clutch 14 is not fully connected. And the clutch 14
Is reduced, the life is improved, and a small clutch can be adopted.

[0027] In this embodiment, the series of signal processing performed by the motor control computer 94, step
The part that executes S2 corresponds to the synchronization control means, the part that executes step S7 corresponds to the torque control means, and the part that executes step S5 constitutes the delay means together with the limit switch 88.

Next, another embodiment of the present invention will be described. The embodiment of FIG. 12 is different from the first embodiment in that the motor output is set to 0 in step S9 executed when the determination in step S5 is NO. The rotation speed Nm of the electric motor 10 is set to the input rotation speed Nin by the synchronous control in step S2.
Since the motor output is set to 0 and the rotation of the sleeve 32 is in a free state in this manner, the clutch 14 can be more smoothly engaged without hunting or the like. The time required for the engagement is further reduced.

When the motor output is set to 0 as described above, the engagement operation of the clutch 14 is stabilized, so that the complete engagement of the clutch 14 can be estimated based on the delay time as shown in FIG. In other words, by resetting the timer TimA in step S10 when in the N range, the elapsed time after the switching operation from the N range to another range is measured,
Instead of the clutch engagement determination in step S5, it is determined in step S11 whether the time measured by the timer TimA has exceeded a predetermined delay time ta. The delay time ta is a delay time set from the shift operation of the shift lever 60 to the complete engagement of the clutch 14 with a margin, and is determined in advance by simulation or experiment. Different values can be set using the vehicle speed, that is, the output shaft rotation speed Nout, as a parameter. Then, when the delay time ta has elapsed, it is considered that the clutch 14 has been completely engaged, and steps S6 and S7 are executed to return to the normal torque control.
In this case, the limit switch 88 becomes unnecessary, and the portion for executing steps S10 and S11 serves as delay means.

The embodiment of FIG. 14 is different from the first embodiment in that the time for the clutch engagement determination in step S5 is limited.
By resetting B, the elapsed time after the switching operation from the N range to another range is measured, and step S
If the determination at step 5 is NO, the timer TimB is set at step S13.
It is determined whether or not the measured time has exceeded the predetermined return time tb.
7 is executed to forcibly return to the normal torque control. With this configuration, even if the determination of YES in step S5 is delayed due to an abnormality of the limit switch 88 or the like, the control returns to the normal torque control after the return time tb elapses. When the accelerator is depressed after returning to the range or the R range, it is possible to avoid such a problem that the vehicle does not easily accelerate. If the accelerator does not accelerate even after stepping on the accelerator, the accelerator is generally depressed more strongly, and unexpectedly sudden acceleration may occur if the return to the normal torque control is delayed. Such a problem can be prevented by restoring. The return time is longer than the delay time from the shift operation of the shift lever 60 to the complete engagement of the clutch 14, and is obtained in advance by simulation, experiment, or the like. Different values may be set using the output shaft rotation speed Nout or the like as a parameter. Note that such a forced return based on the return time tb can be similarly applied to the case where the determination of the engagement of the clutch 14 is performed and the control is returned to the normal torque control, and is also applicable to the embodiment of FIG.

In the embodiment shown in FIG. 15, the engagement of the clutch 14 is determined in another manner, and the flag F1 and the flag F2 are set to "1" in step S14 executed when the engine is in the N range. When the shift lever 60 is switched from the N range, the flags F1 and F2 are set.
S4, S15 to determine whether or not is "1"
Then, step S16 is executed, and the constant value β is added to the target torque To to increase the torque of the electric motor 10 by the constant value β. As the torque of the electric motor 10 is increased, if the clutch 14 is in the disengaged state, the motor rotation speed Nm increases, and the rotation speed between the output shaft rotation speed Nout and the input rotation speed Nin calculated from the reduction ratio i is increased. A speed difference occurs. Further, in step S17 to be executed subsequently, the flag F2 is set to “0”, whereby
In subsequent cycles, step S15 is followed by step S15.
Step 18 is executed. In step S18, it is determined whether or not the motor rotation speed Nin is substantially equal to the input rotation speed Nout. If Nm ≒ Nin, steps S6 and S7 are executed to return to normal torque control. The speed determination in step S18 is performed in consideration of detection errors of the motor rotation speed sensor 78 and the vehicle speed sensor 82. In this embodiment, the part that executes step S18 corresponds to a delay unit.

In step S18, the small gear 1
The engagement of the clutch 14 can also be determined based on whether or not the shaft torque of No. 6 is measured and substantially coincides with the motor torque. Further, the motor output may be set to 0 until the clutch 14 is engaged as shown in FIG. 12, or the torque control may be forcibly returned to the normal torque control after the return time elapses as shown in FIG. Steps S15, S16, and S17 can be omitted. For example, in step S5 of the embodiment of FIG. 6, the same engagement determination as in step S18 may be performed.

While some embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be implemented in other embodiments.

For example, in the above-described embodiment, the three-axis speed reducer 28 is used. However, a two-shaft or planetary gear type speed reducer, or a transmission or the like whose switching ratio can be switched by a clutch or a brake may be used. The present invention can be applied to an electric vehicle without such a speed reducer or transmission.

In the above-described embodiment, the clutch 14 having the synchronizing mechanism is used. However, a clutch of another type, a hydraulic clutch by friction of a multi-plate type or a single-plate type, or the like can be adopted. When a hydraulic clutch is used, the engagement of the clutch can be determined by detecting the hydraulic pressure.

The switching means of the clutch 14 does not necessarily have to be mechanically switched in accordance with the operation of the shift lever 60, but is operated by operating an electric actuator or switching a hydraulic circuit by an electric signal to disconnect and disconnect the connection state. The state may be switched. The manual lever of the hydraulic circuit can be moved by the shift lever 60 to switch the hydraulic clutch.

In the first embodiment, the complete engagement of the clutch 14 is detected by using the limit switch 88. However, various other position detecting means such as an optical type and an electromagnetic type may be used. Is possible.

In the above-described embodiment, the input rotation speed Nin is calculated from the output shaft rotation speed Nout detected by the vehicle speed sensor 82, and the synchronous control is performed so that the input rotation speed Nin and the motor rotation speed Nm substantially match. However, the rotation speed of the small gear 16 may be directly detected, or the motor rotation speed Nm may be divided by the reduction ratio i and compared with the output shaft rotation speed Nout.

In the above embodiment, the rotational speed difference | No |
Is used as a parameter to calculate the torque correction value ΔT. However, a constant value may be set in advance as the torque correction value ΔT. The content of the synchronization control can be changed as appropriate .

Although not specifically exemplified, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims.

FIG. 2 is a schematic diagram illustrating a drive system of an electric vehicle to which the present invention is applied.

FIG. 3 is a sectional view showing a clutch portion provided in the drive system of the embodiment of FIG. 2;

FIG. 4 is a view showing a parking lock mechanism of the embodiment of FIG. 2;

FIG. 5 is a block diagram illustrating a control system of the embodiment in FIG. 2;

FIG. 6 is a slow chart illustrating the operation of motor torque control in the embodiment of FIG. 2;

FIG. 7 is a flowchart specifically illustrating the content of synchronization control in step S2 in FIG. 6;

FIG. 8 is a flowchart specifically illustrating a part of the normal torque control in step S7 in FIG.

FIG. 9 is an example of a data map used for calculating a torque correction value ΔT in step R5 of FIG. 7;

FIG. 10 is an example of a data map used when calculating a torque control value Ta in step Q1 of FIG. 8;

FIG. 11 shows a shift lever D → N in the embodiment of FIG.
6 is a time chart for explaining an example of a change in a motor rotation speed Nm and an output shaft rotation speed Nout when switching is made to D;

FIG. 12 is a flowchart illustrating another embodiment of the present invention.

FIG. 13 is a flowchart illustrating still another embodiment of the present invention.

FIG. 14 is a flowchart illustrating still another embodiment of the present invention.

FIG. 15 is a flowchart illustrating still another embodiment of the present invention.

[Description of Signs] 10: Electric motor 14: Clutch 60: Shift lever 66: Switching means 84: Shift position sensor (selection range detecting means) 86: Accelerator operation amount sensor (accelerator operation amount detecting means) 88: Limit switch 94: Motor control computer Step S2: Synchronous control means Step S5: Delay means Step S7: Torque control means Step S10, S11: Delay means Step S18: Delay means

──────────────────────────────────────────────────続 き Continuing on the front page (72) Eiji Ichioka, Toyota 1st Toyota Town, Aichi Prefecture Toyota Motor Corporation (72) Inventor Kojiro Kuramochi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (56) References JP-A-5-227610 (JP, A) JP-A-61-46802 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60L 9/18 B60K 41 / 28

Claims (1)

(57) [Claims] 1. A shift lever selectively operated to a plurality of ranges including a neutral range and a traveling range, a selection range detecting means for detecting a selection range of the shift lever, and an accelerator operation amount detecting means for detecting an accelerator operation amount. An electric motor comprising: an electric motor that rotationally drives driving wheels; and a torque control unit that performs torque control of the electric motor in accordance with the accelerator operation amount when the shift lever is selectively operated to the travel range. A clutch for connecting and disconnecting the power transmission between the electric motor and the drive wheels; and setting the clutch to a connected state when the shift lever is selectively operated to the travel range. a switching means for the cut-off state of the clutch when the lever is operated to the neutral range, the shift lever is the neutral Les If that has been manipulated to di
The engagement elements of the clutch have substantially the same rotational speed as each other.
Synchronous control means for synchronously controlling the electric motor so that
And when the shift lever is operated to switch from the neutral range to the travel range, the torque of the electric motor by the torque control means until the engagement element of the clutch is considered to be completely engaged. A driving force control device for an electric vehicle, comprising a delay unit for delaying control.