JPH06276611A - Driving force controller for electric vehicle - Google Patents

Abstract

PURPOSE:To improve a life of a clutch which is arranged between an electric motor and drive wheels and switched to an engaging state and a disengaging state according to an operation of a shift lever. CONSTITUTION:A drive power controller for an electric vehicle so torque- controls an electric motor that engaging elements of a clutch become substantially the same rotating speeds at the time of an N range in which a clutch is disengaged (S2). On the other hand, the controller judges whether or not the clutch is completely engaged when a shift lever is switched from the N range to other range (S5), and torque-controls as usual in response to an accelerator operating amount after the clutch is completely engaged (S7).

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 that cuts off power transmission when a shift lever is operated to a neutral range. The present invention 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 which is selectively operated to a plurality of ranges including a neutral range and a running range, and (b) a selection range detecting means which detects the selection range of the shift lever. , (C) accelerator operation amount detecting means for detecting an accelerator operation amount, (d) an electric motor for rotationally driving a drive wheel, and (e) the accelerator operation when the shift lever is selectively operated to the travel range. And a torque control means for controlling the torque of the electric motor according to the amount. In such an electric vehicle, since a series of power transmission paths from the motor shaft of the electric motor to the drive wheels have been directly connected to each other,
For example, if the electric motor breaks down and is locked, the drive wheels are also locked, which makes it difficult to move the vehicle.

On the other hand, in the Japanese Patent Application No. 4-257136 filed earlier by the applicant of the present application, (f) a clutch for connecting and disconnecting power transmission between the electric motor and the drive wheels, and (g) The shift lever is provided with a switching means for bringing the clutch into an engaged state when the shift lever is selectively operated to the traveling range, and to disengaging the clutch when the shift lever is operated to the neutral range. We proposed an electric vehicle that can cut off the power transmission between the electric motor and the drive wheels when operated to the neutral range. In an electric vehicle equipped with such a clutch, coasting is possible by shifting to the neutral range while the vehicle is traveling, but when shifting to a traveling range such as the D (drive) range again after that, , If there is a large difference in rotational speed between the engaging elements of the clutch, the load on the clutch is large and the time required for engagement is long.Therefore, when the clutch is in the disengaged state, the engaging elements of the clutch are substantially separated from each other. The electric motor is controlled synchronously so that the rotation speed is the same.

[0004]

However, even in such an electric vehicle, when the shift lever is shifted from the neutral range to the running range, the electric motor immediately causes the torque control means to change the torque according to the accelerator operation amount. Since the control is performed, when the driver performs a shift operation while depressing the accelerator, the motor torque increases before the clutch is completely engaged, which puts a heavy burden on the clutch and significantly shortens the clutch life. there were.

The present invention has been made in view of the above circumstances. An object of the present invention is to dispose between an electric motor and a drive wheel and switch between a connected state and a disconnected state according to a shift lever operation. It is to improve the life of the used clutch.

[0006]

In order to achieve the above 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 is performed until the clutch is completely engaged. In the present invention, as shown in the claim correspondence diagram of FIG. 1, (a) a shift lever which is selectively operated to a plurality of ranges including a neutral range and a running range, and (b) the shift thereof. A selection range detecting means for detecting a selection range of the lever, (c) an accelerator operation amount detecting means for detecting an accelerator operation amount, and (d) an electric motor for rotationally driving the drive wheels,
(E) A driving force control device for an electric vehicle, comprising: torque control means for controlling torque of the electric motor according to the accelerator operation amount when the shift lever is selectively operated to the travel range. ) A clutch for connecting and disconnecting power transmission between the electric motor and the drive wheels,
(G) switching means for bringing the clutch into an engaged state when the shift lever is selectively operated to the traveling range and disengaging the clutch when the shift lever is operated to the neutral range; ) Torque control of the electric motor by the torque control means until the engagement element of the clutch is considered to be completely engaged when the shift lever is operated to switch from the neutral range to the travel range. And a delay means for delaying.

[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 drive wheels are separated from each other. Power transmission is cut off. Therefore, when the electric motor fails and is locked, the vehicle can be easily moved by operating the shift lever to the neutral range and disconnecting the electric motor from the drive wheels. Even when rotation occurs, if the shift lever is operated to the neutral range, the electric motor and the drive wheels are separated, and it is possible to easily avoid the traveling abnormality of the vehicle due to the abnormal rotation of the electric motor. Further, since the power transmission can be interrupted by the clutch in this way, 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 the electric vehicle is increased.

On the other hand, when the shift lever is operated to switch from the neutral range to the travel range, the torque control means operates according to the accelerator operation amount until it is considered that the engagement element of the clutch is completely engaged. The torque control of the electric motor is delayed by the delay means. Therefore, for example, even if the driver shifts the shift lever to the travel range while depressing the accelerator after performing inertial running in the neutral range, the motor torque is adjusted according to the accelerator operation amount while the clutch is incompletely connected. Therefore, it is possible to prevent the clutch from being lifted up, reduce the load on the clutch, improve the life, and use a small clutch.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 2 is a skeleton diagram showing the drive system of the electric vehicle of this embodiment. The motor shaft 12 of the electric motor 10 is adapted to be connected to a pinion gear 16 via a clutch 14, and the pinion gear 16 thereof is also shown. Engages with a large gear 20 provided on the intermediate shaft 18. On the intermediate shaft 18, a small gear 22 is provided 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, and 26, the rotation of the electric motor 10 is kept at a predetermined reduction ratio i (= rotational speed Nin of the small gear 16 / rotational speed Nout of the output shaft 24). It is decelerated, transmitted to the output shaft 24, and further transmitted to a pair of drive wheels via a differential device or the like not shown. Speed reducer 2 including the 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 has a clutch hub 30 spline-fitted to the motor shaft 12, and a sleeve 32 spline-fitted to the outer peripheral portion of the clutch hub 30. And a plurality of shifting keys 34 that are fitted into a plurality of grooves formed on the outer peripheral portion of the clutch hub 30 and are pressed against the inner peripheral surface of the sleeve 32 by a spring, and are rotated relative to the shifting keys 34. The tapered portion 38 that is engaged with the clutch gear 36 and is integrally provided with the clutch gear 36
And a synchronizer ring 40 which is rotatably fitted to the outer periphery of the clutch gear 36. The clutch gear 36 is splined to the small gear 16 which is rotatably disposed on the motor shaft 12 via a bearing 42. It is fitted.
Then, as shown in the figure, the sleeve 32 has the clutch hub 3
In a disengaged state in which only 0 is engaged, power transmission between the motor shaft 12 and the small gear 16 is interrupted, 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 and the clutch gear 36 are engaged with each other, power transmission between the motor shaft 12 and the small gear 16 is allowed. When switching from the disengaged state to the connected state, the clutch gear 36 and the motor shaft 12 are synchronously rotated by the friction between the synchronizer ring 40 and the taper portion 38, so that the clutch gear 36 and the motor gear 12 are rotated between the motor shaft 12 and the pinion gear 16. Even if there is a rotation difference, the sleeve 32 meshes with the clutch gear 36 relatively smoothly.

An annular groove 44 is formed on the outer peripheral surface of the sleeve 32.
Is provided, and the shift fork 46 is engaged so as to be relatively rotatable. The shift fork 46 is provided on the motor shaft 12
It is fixed to a shift rod 48 which is arranged so as to be movable in the axial direction in parallel with the clutch rod 14. When the shift rod 48 is moved in the axial direction, the sleeve 32 is moved in the left-right direction in the drawing and the clutch 14 is moved. Can be switched. The shift rod 48 is supported by a housing 50 so as to be movable in the axial direction, and the spring 5 is always provided.
2 is urged in the left direction in the figure, that is, in the direction approaching the parking lock rod 54.

The parking lock rod 54 is arranged in a direction orthogonal to the axis of the shift rod 48, specifically in the vertical direction in the drawing, is movable in the axial direction, and has a lever at the upper end. It is connected to 56. The lever 56 is connected to a shift lever 60 via a cable 58, and the shift lever 60 has “P (parking)”, “R (reverse)”, “N (neutral)”, and “D (drive)”. By selecting and operating each range, the parking lock rod 54 is moved in the vertical direction in the drawing. The P range is an operation range when the vehicle is parked, the R range is an operation range when the vehicle is moved backward, and the N range is when the power transmission between the electric motor 10 and the drive wheels is cut off. In the operating range,
The D range is the operating range for moving the vehicle forward,
The R and D ranges correspond to the running 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 portion 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 biasing force of the spring 52. Thereby, the sleeve 3
2 is also moved to the right, the engagement with the clutch gear 36 is released, and the clutch 14 is brought into the disengaged state. Figure 3
In this case, 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, the D, R, or P range, the shift cam 6 is operated.
The engagement between 2 and the cam roller 64 is released, the shift rod 48 is moved to the left in the drawing 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, the shift rod 48, the spring 52, the parking lock rod 54, the lever 56,
Cable 58, shift cam 62, and cam roller 64
Thus, a switching unit 66 that switches the clutch 14 according to the selected 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 biasing force of the torsion coil spring 72 by operating the shift lever 60 to the P range and moving the parking lock rod 54 upward. , Meshes with a parking lock gear 74 provided on the motor shaft 12 to mechanically prevent rotation of 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 blocked by the rotation of the drive wheels.

FIG. 5 is a block diagram illustrating a control system provided in the electric vehicle of this embodiment. The electric motor 10 is supplied with drive power from a power source 90 such as a battery via a motor drive control circuit 92. By doing so, it is rotationally driven in both forward and reverse directions. The motor drive control circuit 92 is an inverter or the like, and controls the torque of the electric motor 10 by changing the frequency and current of the drive power according to the command signal ST supplied from the motor control computer 94, and at the same time, controls the electric motor 10. The regenerative braking is performed to accumulate the electric energy generated by the forced rotation in the power source 90. The motor control computer 94 is a CP
The RAM 9 includes a U 96, a RAM 98, a ROM 100, a clock signal source 102 such as a crystal oscillator, an A / D converter (not shown), an input / output interface circuit, and the like.
The signal processing is performed in accordance with a program stored in advance in the ROM 100 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. .

In the motor control computer 94,
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, etc. are connected, and a motor rotation speed signal SNm representing the rotation speed Nm of the motor shaft 12 and a rotation speed of the output shaft 24. The output shaft rotation speed signal SNout representing Nout, the shift position signal SSh representing the selection range of the shift lever 60, the accelerator operation amount signal SAc representing the accelerator pedal operation amount Ac, and the clutch 14 being in a completely engaged connection state. The clutch engagement signal SC or the like representing the above is supplied. The motor rotation speed sensor 78 detects the motor rotation speed Nm by distinguishing whether the vehicle is forward rotation forward or reverse rotation reverse. For example, a pair of pulse signals having different phase shifts in the forward and reverse rotations is used to rotate the motor. It is configured to output in accordance with. Further, the limit switch 88 is arranged in the vicinity of the shift rod 48, and the shift rod 48 is moved to the left in FIG. 3 so that the sleeve 32 is engaged with the clutch hub 30 and the clutch gear 36 while meshing. Shift rod 4
The clutch engagement signal SC is switched between ON and OFF by engaging with No. 8. The shift position sensor 84 corresponds to selection range detecting means, and the accelerator operation amount sensor 86 corresponds to accelerator operation amount detecting means.

The motor control computer 94 controls the torque of the electric motor 10 according to the flow chart shown in FIG. This flowchart is repeatedly executed with a cycle time of, for example, several tens of msec. First, in step S1, the shift position signal SS
Based on h, it is determined whether or not the selected 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 it is the N range, step S2 and subsequent steps are executed, but otherwise. Step S4 and subsequent steps are executed. The step S2 executed in the case of the N range is an engaging element of the clutch 14, that is, the engagement element of the clutch 14 so that the clutch 14 is not heavily burdened when the shift lever 60 is returned to the D or R traveling range again while the vehicle is traveling. The electric motor 10 is synchronously controlled so that the sleeve 32 spline-fitted to the clutch hub 30 and the clutch gear 36 have substantially the same rotational speed. In the next step S3, the flag F1 is set to "1".

The synchronous control in step S2 is performed according to the flow chart of FIG. 7, and in step R1, the motor rotation speed signal SNm and the output shaft rotation speed signal SNout.
Motor rotation speed Nm and output shaft rotation speed N based on
The 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 pinion 16. In the following step R3, the rotational speed difference No = Nm-N between the motor rotational speed Nm and the input rotational 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 greater than or equal to a predetermined determination value a. The determination value a is used to determine whether the rotational speed difference | No | is small enough to allow the clutch 14 to be smoothly connected. If | No | <a, the current motor rotational speed Nm is determined. Since 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 in step R7, the torque of the electric motor 10 is changed to the target torque To. Control so that it substantially matches.

If the determination in step R4 is YES,
That is, when the rotational speed difference | No | is equal to or greater than the determination value a, it is desirable to change the rotational speed of the electric motor 10 so that the clutch 14 can be smoothly connected. In step R5, the torque correction value ΔT To calculate. The torque correction value ΔT is obtained by a data map, an arithmetic expression, or the like as shown in FIG. 9, which is stored in advance in the ROM 100 or the like using the rotational speed difference | No | as a parameter. Then, 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 set. In order to reduce the torque, the torque correction value ΔT is subtracted from the current target torque To in step R8 to obtain a new target torque To, and a command signal ST representing the target torque To is output to output the torque of the electric motor 10. 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, the current target torque To is increased in step R9 in order to increase the motor rotation speed Nm.
Is added to the torque correction value ΔT to obtain a new target torque To, and the command signal ST representing the target torque To is output to increase the torque of the electric motor 10 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, if the determination in step S1 is NO, that is, if the selection range of the shift lever 60 is not the N range, then in step S4 it is determined whether the flag F1 is "1". . Since the flag F1 is set to "1" in step S3 in the case of N range,
Immediately after the shift lever 60 is switched from the N range, F1 = 1 and step S5 is executed. In step S5, it is determined based on the clutch engagement signal SC supplied from the limit switch 88 whether or not the clutch 14 is in the completely engaged connection state, and the current state in step S8 is determined until the clutch 14 is completely engaged. The target torque To, in other words, the final target torque To in the synchronous control of step S2 is maintained, but if the clutch 14 is in the completely engaged and engaged state, the flag F1 is set to "0" in step S6 and the step S7 is performed. To perform normal torque control.
By setting the flag F1 = 0, the normal torque control of step S7 is immediately performed following step S4 in the subsequent cycles.

The normal torque control in step S7 is as follows.
Depending on the selection range of the shift lever 60, the electric motor 10 is calculated based on the accelerator operation amount Ac and the motor rotation speed Nm.
In the case of the D range, for example, in the case of the D range, the electric motor 10 is rotationally driven in the forward rotation direction in which the vehicle moves forward, and according to the data map as shown in FIG. The 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 used as the target torque T.
By outputting the command signal ST as o, the torque of the electric motor 10 is controlled so as to match the target torque To, that is, the torque control value Ta. When a predetermined braking condition is satisfied, such as when the brake pedal is operated at a speed equal to or higher than a predetermined vehicle speed, a command signal ST for generating a regenerative braking torque is output, and the engine brake in the automobile of the internal combustion engine is output. Generate a braking torque similar to
In addition, the magnitude is controlled, and electric power corresponding to the braking torque is stored in the power source 90. In the R range, the electric motor 10 is rotationally driven in the reverse rotation direction in which the vehicle moves in the reverse direction, and torque control is performed based on the accelerator operation amount Ac and the motor rotation speed Nm as in the D range. In the case of the P range, the target torque To = 0 and the motor output are set to 0.

Here, when the N range is shifted to the D range while the vehicle is traveling, the target torque To during the synchronous control is maintained in step S8 regardless of the accelerator operation until the clutch 14 is completely engaged. Therefore, when returning to the normal torque control in step S7, the motor torque may suddenly increase and a shock may occur. Therefore, it is desirable to gradually increase the torque as shown in FIG. That is, in step Q1, the torque control value Ta is calculated from the data map as shown in FIG. 10 based on the accelerator operation amount Ac and the motor rotation speed Nm, and then in step Q2, the current target torque To is set to a predetermined constant value. It is determined whether 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 as the target torque To in step Q3, but (To + α) ≦ Ta
In the case of, the target torque To is set to a constant value α in step Q4.
Only 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, so that even when the torque control value Ta calculated in step Q1 according to the accelerator operation amount Ac is large, 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.

Thus, in the electric vehicle of this embodiment, when the shift lever 60 is operated to the N range, the clutch 14
Is cut off and the power transmission between the electric motor 10 and the speed reducer 28 is cut off. Therefore, when the electric motor 10 fails and is locked, the shift lever 60 is operated to the N range to move the electric motor. By separating 10 and the wheels, the vehicle can be easily moved. Even when the electric motor 10 causes an abnormal rotation such as reverse rotation due to an abnormality in the motor control system, the shift lever 60 is operated to the N range to disconnect the electric motor 10 from the wheels, thereby causing the abnormal rotation of the electric motor 10. It is possible to easily avoid the traveling abnormality of the vehicle due to. 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 according to the operation of the shift lever 60, the electric motor can be reliably operated even when the electric system is abnormal as compared with the case where the electric actuator is used for switching. 10 and the wheel can be separated.

Further, since the power transmission can be interrupted by the clutch 14 in this way, by operating the shift lever 60 to the N range while the vehicle is traveling, it is possible to perform coasting and to freely operate the electric vehicle. 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.
Since the torque control of the electric motor 10 is performed so as to substantially coincide with the above, 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 on the clutch 14 is applied. Is small, the life is improved, and a small clutch can be adopted.

FIG. 11 shows a shift lever 60 while the vehicle is running.
6 is an example of a time chart showing changes in the motor rotation speed Nm and the output shaft rotation speed Nout when the is operated from the “D” range to the “N” range and then returned to the “D” range. In FIG. 11, the solid line represents a case where the vehicle speed, that is, the output shaft rotation speed Nout increases in the N range on a downhill, and the dashed-dotted line represents the vehicle speed, that is, the output shaft rotation speed Nout decreases in the N range, on a flat ground or an uphill slope. In both cases, the torque control of the electric motor 10 is performed so that the motor rotation speed Nm substantially matches the input rotation speed Nin according to the output shaft rotation speed Nout. Therefore, the N range is shifted to the D range. When the lever 60 is returned, 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 is
When the range is switched to another range, the normal torque control according to the accelerator operation amount Ac is not performed until the clutch 14 is completely engaged, and therefore, for example, after coasting in the N range. Even when the driver shifts the shift lever 60 to the D range or the R range while depressing the accelerator, it is avoided that the motor torque is increased in accordance with the accelerator operation amount Ac in the state where the clutch 14 is incompletely connected. Also in this respect, the clutch 14
The load on the engine is reduced, the life is improved, and a small clutch can be adopted.

In the present embodiment, of the series of signal processing performed by the motor control computer 94, the part that executes step S7 corresponds to the torque control means, and the part that executes step S5 together with the limit switch 88 and the delay means. Are configured.

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 the input rotation speed Nin in the synchronous control in step S2.
Since the motor output is set to 0 and the rotation of the sleeve 32 becomes free, the clutch 14 can be engaged more smoothly without causing hunting or the like. , The time required for engagement is further shortened.

When the motor output is set to 0 as described above, the engaging operation of the clutch 14 is stabilized, so that the complete engagement of the clutch 14 can be estimated from the delay time as shown in FIG. That is, by resetting the timer TimA in step S10 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 exceeds a predetermined delay time ta. The delay time ta is a delay time from the shift operation of the shift lever 60 to the complete engagement of the clutch 14 with a margin, and is obtained 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. When the delay time ta elapses, it is considered that the clutch 14 is completely engaged, and steps S6 and S7 are executed to return to the normal torque control.
In this case, the limit switch 88 is not necessary, and the part that executes steps S10 and S11 serves as a delay unit.

The embodiment of FIG. 14 limits the time for determining the clutch engagement in step S5, as compared with the first embodiment. When the range is N, the timer Tim is used in step S12.
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 in 5 is NO, the timer TimB is set in step S13.
It is judged whether or not the measurement time of T has exceeded a predetermined restoration time tb, and if it exceeds the restoration time tb, steps S6, S
7 is executed to forcibly return to normal torque control. By doing so, even if the engagement determination in step S5 becomes YES due to an abnormality in the limit switch 88 or the like, if the return time tb elapses, the normal torque control is resumed. It is possible to avoid the inconvenience of not easily accelerating when the accelerator is depressed after returning to the range or the R range. If the accelerator does not accelerate even when the accelerator is depressed, generally the accelerator will be depressed more strongly, and if the return to normal torque control is delayed, sudden acceleration may occur unexpectedly. If it is restored, such a problem can be prevented. The return time is longer than the delay time from the shift operation of the shift lever 60 until the clutch 14 is completely engaged, and is obtained in advance by simulation, experiment, or the like. Different values may be set using the output shaft rotation speed Nout and the like as parameters. It should be noted that such a forced return by the return time tb can be similarly applied in the case where the engagement determination of the clutch 14 is performed to return to the normal torque control, and can also be applied to the embodiment of FIG. 12 and the like.

In the embodiment shown in FIG. 15, the engagement determination of the clutch 14 is performed in a different manner, and the flag F2 is set to "1" together with the flag F1 in step S14 executed when the N range is set. When the shift lever 60 is switched from the N range, the flags F1 and F2 are
Steps S4 and S15 for determining whether is "1"
Subsequently, step S16 is executed to add the constant value β to the target torque To to increase the torque of the electric motor 10 by the constant value β. By increasing the torque of the electric motor 10, the motor rotation speed Nm increases when the clutch 14 is in the disengaged state, and the rotation speed is increased between the output shaft rotation speed Nout and the input rotation speed Nin calculated from the reduction ratio i. Speed difference will occur. Further, in step S17 executed subsequently, the flag F2 is set to "0", whereby
In the subsequent cycles, step S15 is followed by step S
Execute 18. In step S18, it is determined whether or not the motor rotation speed Nin and the input rotation speed Nout are substantially equal. 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 the delay means.

In step S18, the small gear 1
It is also possible to determine the engagement of the clutch 14 by measuring the shaft torque of No. 6 and determining whether or not the torque substantially matches the motor torque. Further, the motor output can be set to 0 until the clutch 14 is engaged as shown in FIG. 12, or the normal torque control can be forcibly returned after the return time has elapsed as shown in FIG. The steps S15, S16 and S17 may be omitted, and for example, in step S5 of the embodiment shown in FIG. 6, the same engagement determination as in step S18 may be performed.

Although some embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be carried out in other modes.

For example, the triaxial speed reducer 28 is used in the above embodiment, but a biaxial or planetary gear type speed reducer, or a transmission capable of switching the speed reduction ratio by a clutch or a brake may be used. The present invention can be applied to an electric vehicle that does not include such a speed reducer or a transmission.

Further, although the clutch 14 having the synchronizing mechanism is used in the above-mentioned embodiment, a clutch of another system, a multi-plate type or a single plate type hydraulic clutch by friction, or the like may be adopted. When a hydraulic clutch is used, it is also possible to detect the hydraulic pressure and determine the engagement of the clutch.

Further, the switching means of the clutch 14 does not necessarily have to be mechanically switched according to the operation of the shift lever 60, and the electric signal is used to operate the electric actuator or switch the hydraulic circuit to disconnect the connection state. The state may be switched. It is also possible to move the manual valve of the hydraulic circuit by the shift lever 60 to switch the hydraulic clutch.

Further, although the limit switch 88 is used to detect the complete engagement of the clutch 14 in the first embodiment, various other position detecting means such as an optical type and an electromagnetic type may be used. Is possible.

In the above 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. Although it has been performed, 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 |
Although the torque correction value ΔT is calculated with the parameter as a parameter, a constant value may be set in advance as the torque correction value ΔT. For example, the rotational speed difference | No | The content of the synchronization control can be changed as appropriate. Note that such synchronization control is not always essential.

Although not illustrated one by one, 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 drawings]

FIG. 1 is a diagram corresponding to a complaint.

FIG. 2 is a skeleton 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.

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

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

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

7 is a flowchart for specifically explaining the content of the synchronization control in step S2 in FIG.

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

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

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

FIG. 11 is a view showing the shift lever D → N in the embodiment of FIG.
9 is a time chart illustrating an example of changes in the motor rotation speed Nm and the output shaft rotation speed Nout when switching is made from → D.

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

FIG. 13 is a flow chart illustrating yet another embodiment of the present invention.

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

FIG. 15 is a flow chart illustrating another embodiment of the present invention.

[Explanation of symbols]

10: Electric motor 14: Clutch 60: Shift lever 66: Switching means 84: Shift position sensor (selection range detection means) 86: Accelerator operation amount sensor (accelerator operation amount detection means) 88: Limit switch 94: Motor control computer step S5: Delay means Step S7: Torque control means Steps S10, S11: Delay means Step S18: Delay means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiji Ichioka, 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor, Koujiro Kuramochi, 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd.

Claims (1)

[Claims] 1. A shift lever which is selectively operated to a plurality of ranges including a neutral range and a travel range, a selection range detecting means which detects a selection range of the shift lever, and an accelerator operation amount detecting means which detects an accelerator operation amount. An electric vehicle including: an electric motor that rotationally drives driving wheels; and torque control means that controls the torque of the electric motor according to the accelerator operation amount when the shift lever is selectively operated to the travel range. In the driving force control device, the clutch for connecting and disconnecting the power transmission between the electric motor and the drive wheel, and the clutch when the shift lever is selectively operated to the travel range, the clutch is put in the connected state. Switching means for disengaging the clutch when the lever is operated to the neutral range; and the shift lever for setting the neutral position. A delay means for delaying torque control of the electric motor by the torque control means until it is considered that the engagement element of the clutch is completely engaged when a switching operation is performed from the engine range to the travel range. A driving force control device for an electric vehicle, characterized in that