JP3446228B2 - Vehicle drive system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle drive device which is driven by a motor in addition to an engine.

[0002]

2. Description of the Related Art Among recent vehicles, the number of four-wheel drive vehicles tends to increase. However, in order to reduce weight and the like, a main drive wheel that drives one of the front left and right wheels and the rear left and right wheels by an engine In addition, the other wheel is used as an auxiliary drive wheel driven by a motor. Japanese Unexamined Patent Publication No. 2-12036 discloses a motor that uses two motors having different driving forces to change the type and number of motors to be operated according to the gear stage of a transmission, that is, a motor. -It has been proposed to change the auxiliary driving force of the motor.

In Japanese Patent Laid-Open No. 57-74222, distribution of hydraulic pressure to two hydraulic motors (hydraulic cylinders) on the left and right is automatically performed according to road surface loads applied to the left and right auxiliary drive wheels. Then, the one to which the function of the differential device is added has been proposed.

In Japanese Patent Laid-Open No. 63-38031, two electric motors, left and right, are used. As the vehicle speed increases, the generated voltage is increased so that the torque generated by the motor becomes constant. Along with the manual switch,
It has been proposed that the drive execution and the drive stop can be selected by switching.

[0005]

By the way, in a vehicle in which the auxiliary drive wheels are driven by a motor, it is important under any circumstances whether or not the motor is driven. Performing the motor drive unnecessarily is not preferable from the viewpoint of fuel saving because the drive energy of the motor must be finally obtained from the engine. Further, if the execution of the motor is unnecessarily restricted from the viewpoint of fuel economy, the meaning of the motor drive will be diminished.

Further, the four-wheel drive state in which the motor drive is executed and the two-wheel drive state in which the motor drive is stopped bring about a considerable difference in vehicle characteristics such as vehicle stability and turning characteristics. Become. As is already clear from the above, it is sufficient to set the drive region for executing the drive of the motor, for example, from the viewpoint of fuel saving to a uniform one, for example, during acceleration. It cannot be solved.

The present invention has been made in consideration of the above circumstances, and it is an object of the present invention to provide a vehicle drive device capable of more appropriately setting the drive region of the auxiliary drive wheel by the motor. And

[0008]

In order to achieve the above object, the present invention has the following first structure. That is, as described in claim 1 in the claims, one of the left and right front wheels and the left and right rear wheels is a main drive wheel driven by the engine via the transmission and the differential device. In a vehicle in which the other wheel is an auxiliary drive wheel driven by a motor, the auxiliary drive wheel is driven in the same direction as the driving direction of the main drive wheel by the engine only when a predetermined drive range is reached. To drive,
Drive control means for controlling the drive of the motor, and drive area changing means for prohibiting the drive of the motor when the lateral G is a predetermined value or more based on the lateral G acting on the vehicle body.
Is provided. In order to achieve the above object, the present invention has the following second construction. That is, as described in claim 2 in the claims, one of the left and right front wheels and the left and right rear wheels is a main drive wheel driven by the engine via the transmission and the differential device. In a vehicle in which the other wheel is an auxiliary drive wheel driven by a motor, the auxiliary drive wheel is driven in the same direction as the driving direction of the main drive wheel by the engine only when a predetermined drive range is reached. Drive control means for performing drive control of the motor so that the motor is driven, the drive range is set with the steering wheel steering angle and the vehicle speed as parameters, and the steering angle is small and the vehicle speed range is low. The configuration is such that the motor is driven, and the drive of the motor is prohibited with an increase in the steering angle or an increase in the vehicle speed. In order to achieve the above object, the present invention has the following third construction. That is, as described in claim 3 of the claims, one of the left and right front wheels and the left and right rear wheels is a main drive wheel driven by the engine via the transmission and the differential device. In a vehicle in which the other wheel is an auxiliary drive wheel driven by a motor, the auxiliary drive wheel is driven in a direction opposite to the driving direction of the main drive wheel by the engine only when a predetermined drive range is reached. To drive,
A drive control means for controlling the drive of the motor and a drive area changing means for prohibiting the reverse drive of the motor at a low vehicle speed are provided. In order to achieve the above object, the present invention has the following fourth construction. That is, as described in claim 4 in the claims, one of the left and right front wheels and the left and right rear wheels is a main drive wheel driven by the engine via the transmission and the differential device. , The other wheel is
In a vehicle that is an auxiliary drive wheel driven by
Drive control means for controlling the drive of the motor so that the auxiliary drive wheels are driven in the same direction as the drive direction of the main drive wheels by the engine only when a predetermined drive range is reached, and a bad road. In this case, the drive area changing means for enlarging the drive area as compared with the case of a good road is provided.

[0009]

According to the present invention, basically, the drive area of the motor can be changed to an optimum one in accordance with the condition of the vehicle. Therefore, the motor drive is used. This is preferable for maintaining the fuel efficiency and the vehicle characteristics while improving the driving ability of the entire vehicle. In particular, the following effects are obtained according to each claim. According to the invention described in claim 1, it is preferable in order to prevent a large change in the vehicle characteristics, particularly the deterioration of the turning characteristics, by prohibiting the motor drive during a sharp turn in which the lateral G becomes large. According to the invention described in claim 2,
At low vehicle speeds when the demand for drive assistance from the motor is high, the motor assist drive is performed on condition that the steering angle of the steering wheel is small when the vehicle stability is high, and effective drive assistance by the motor is provided to stabilize the vehicle stability. It is preferable to carry out without damaging.

According to the third aspect of the present invention, reverse driving is improved to improve braking performance, and reverse driving is prohibited at low vehicle speeds where large braking capability is not required, which is preferable in terms of improving fuel efficiency. Will be things. According to the invention described in claim 4, when the road is a bad road in which it is difficult to sufficiently transmit the driving force to the road surface as compared with a good road, the driving area in which the auxiliary drive is performed by the motor is expanded to increase the driving force. Is preferable for effectively transmitting to the road surface.

[0011]

[Example] Description of hydraulic system (FIG. 1) In FIG. 1, 1FL is a left front wheel, 1FR is a right front wheel, 1R
L is the left rear wheel, and 1RR is the right rear wheel. An engine 2 is arranged in front of the vehicle body, and a driving force of the engine 2, that is, a generated torque, is transmitted to a differential device 5 via a clutch 3, a manual transmission 4 having five forward gears and one reverse gear. Then, from the differential device 5, the left front wheel 1FL is passed through the left drive shaft 6L.
The engine drive force is transmitted to the right front wheel 1FR via the right drive shaft 6R.

The left and right front wheels 1FL and 1FR, which are the steered wheels, are linked by a steering link 7 such as a tie rod, and the steering link 7 and the handle 8 are linked via a rack and pinion mechanism 9.

The left and right rear wheels 1RL, 1RR are the engine 2
Separately independently of, a pair of left and right hydraulic motors ML, MR
Is driven by. That is, the left rear wheel 1RL is connected to the left motor M via the left drive shaft 11L.
Driven by L, the right rear wheel 1RR has a right drive shaft 11
It is adapted to be driven by the right motor MR via R. This motor ML, that is, the left drive shaft 11L
And the motor MR, that is, the right drive shaft 11R, are separated from each other and can be driven independently on the left and right sides. The left and right drive shafts 11L and 11R are
The hydraulic clutch 12 can be engaged and disengaged.

The motor ML (MR) is of a turbine type (impeller type), has a first connection port La (Ra) and a second connection port Lb (Rb), and La (Ra). ) To Lb (Rb)
When high-pressure oil liquid flows to, it will rotate in the forward direction,
When the high-pressure oil liquid flows in the opposite direction, the rotation is in the backward direction. The motors ML and MR have the same specifications, and the total value of the maximum generated torque is about 1/3 to 1/2 of the maximum generated torque of the engine 2. In the embodiment, the rear wheel drive by the motors ML and MR is executed only under a predetermined condition described later. That is, the left and right front wheels 1FL by the engine 2,
Even when 1FR is driven, the left and right rear wheels 1RL, 1
The RR may not be driven by the motors ML and MR.

P is a pump as a hydraulic pressure generation source, and this pump P is of a variable capacity type and has an output shaft 2 of the engine 2.
It is driven by the drive pulley 13, the belt 14, and the driven pulley 15 by a. The high-pressure oil liquid pumped from the reservoir tank 16 by the pump P is discharged to the high-pressure line 18 to which the check valve 17 is connected. From the high-pressure line 18, first and second hydraulic pressure supply lines 31A and 31B connected to the check valve 10 or 32 and parallel to each other are led out. Further, the release line 23 is led out from the reservoir tank 23.
Furthermore, the connection ports La and Lb (R of the motor ML (MR) are
a, Rb), lines 20L and 21L parallel to each other
(20R, 21R) has been derived.

The lines 20L and 21L of the left motor ML are the switching valve VVA, the lines 19 and 19L and the lines 22 and 22L which are parallel to each other, and the switching valves VVB.L and VVE.
Using L, the first supply line 31A and the release line 23
Is selectively connectable to. Similarly, the lines 20R and 21R of the right motor MR are connected to the switching valve VVA,
Lines 19 and 19R and lines 22 and 22 parallel to each other
R and the switching valves VVB ・ R and VVE ・ R
The first supply line 31A and the release line 23 can be selectively connected.

To the second common supply line 31B, a switching valve VVI is connected downstream of the check valve 32 and a flow dividing valve 34 is connected further downstream. One branch supply line 33L branched into two by the flow dividing valve VVI is connected to the line 19L, and the other branch supply line 33R is connected to the line 19R.

An accumulator 41 for storing high pressure oil pressure is connected to the high pressure line 18. For this high-pressure line 18, line 20L (20R)
Are connected by a passage 42L (42R). In this passage 42L (42R), a check valve 43L (43
R) and the switching valve VVF · L (VVF · R) are connected. The passages 43L and 43R are parallel to each other, and each of the valves VVA, VVB · L (VVB · R), VVE · L (V
VE / R), VVI, the shunt valve 34, etc. are bypassed.

The line 20L (20R) and the line 21
The L (21R) is communicated with the communication passage 51L (51R), and the variable orifice VVC · L (VVC · R) is connected to the communication passage 51L (51R).

An actuator for connecting and disconnecting the clutch 12 is designated by reference numeral 61. This actuator 61
The supply line 62 for the high pressure line 18 and the discharge line 63 for the release line 23, the switching valve VVJ
, And both lines 62 and 63 can be shut off by the switching valve VVJ.

The left and right motors ML and MR are connected to each other by a communication passage 71, and an on-off valve V is provided in the communication passage 71.
VD is connected. The release line 23 is connected to the high pressure line 18 on the upstream side (pump P side) of the check valve 17 via a load / unload valve VVH, and on the downstream side of the check valve 17. At the safety valve VVG.

Description of Control Modes (Table 1) In this embodiment, there are a total of eight types of control modes, as will be described later, and each of the above-mentioned valves when each mode is executed. The operating conditions are summarized in Table 1 below. In this table, the symbols "L" and "R" for identifying the left and right are omitted. The load / unload valve VVH not shown in Table 1 is controlled to be opened / closed so that the pressure in the high pressure line 18 falls within a predetermined pressure range between a lower limit value and an upper limit value.

[0023]

[Table 1]

In each of the control modes shown in Table 1, the operating state of the valve that performs the main function will be described in detail.
It is as follows. (1) Integrated mode As will be described later in detail, the integrated mode controls the driving of the motors ML and MR so that the left and right rear wheels 1RL and 1RR have the same rotational speed. There are two types: drive (drive assistance) and reverse drive (braking). In this integrated mode,
The clutch 12 is engaged (the switching valve VVJ opens the line 62 and closes the line 63), and the switching valve VVB · L (V
The operation modes of VB.R), VVE.L (VVE.R) and VVI are set to the states shown in FIG. In this state, the switching valve VVA is controlled to switch the hydraulic pressure supply direction according to the forward drive or the reverse drive (setting the forward and reverse directions of the motors ML and MR), and to the motors ML and MR. The supply flow rate is controlled (hydraulic pressure supply using the first supply line 31A).
In reverse drive, a larger deceleration is obtained than in a hydraulic lock mode described later, but it goes without saying that the rear wheels 1RL, 1RR rotate in a direction opposite to the traveling direction of the vehicle. It does not give driving force.

(2) Independent mode In the independent mode, as will be described in detail later, the motor ML is such that the left and right rear wheels 1RL and 1RR respectively have target rotational speeds independently set. , MR drive control is performed. There are two types of drive, that is, forward drive and reverse drive, as in the case of the integrated mode. In this independent mode, the clutch 12 is released (the switching valve VVJ closes the line 62 and opens the line 63). Switching valve VVE / L (VVE / R)
The operating mode of the switching valve VVA is as shown in FIG.
Is set to the central switching position and the first supply line 31A is cut off. The switching valve VVI is set to the open position, and the hydraulic pressure supply mode using the second supply line 31B is set. In this state,
The switching valve VVB / L (VVB / R) is controlled to switch the hydraulic pressure supply direction according to forward drive or reverse drive (motor M).
L, MR forward / reverse direction setting) and motors ML, M
The supply flow rate for R is controlled.

(3) LSD mode The LSD mode obtains an operation limiting function and is a switching valve V
VB • L and VVB • R are lines 20L and 21L (2
Both 0R and 21R) are closed to completely shut off the supply and discharge of hydraulic pressure to and from the motors ML and MR. And
The on-off valve VVD is opened, and the left and right motors ML and MR are communicated with each other in the closed left and right hydraulic paths.
It is prevented that a large rotation difference is generated between the ML and the MR. In this LSD mode, the variable orifice VV
C / L (VVC / R) is fully closed

(4) Hydraulic lock mode The hydraulic lock mode has a passage resistance, that is, a variable orifice V.
The deceleration force is obtained by using the throttle resistance of VC · L (VVC · R). In this hydraulic lock mode, the switching valve V
The VB / L and VVB / R are in the central switching position, the lines 20L, 21L, 20R and 21R are shut off, and the on-off valve VVD is closed. And the variable orifice V
VC / L and VVC / R are opened. In this state, the oil liquid circulates in the closed hydraulic circuit formed by including the variable orifices VVC.L (VVC.R) in response to the rotation of the motor ML (MR). However, the variable orifice VVC ・ L (VVC ・ R) through which the oil liquid passes during circulation
The throttle resistance of (2) gives a deceleration force to the vehicle. Then, the opening amounts of the variable orifices VVC · L and VVC · R are controlled so as to become smaller as the vehicle deceleration increases (variable orifices VVC · L, V depending on the deceleration).
The setting of the VC / R opening is illustrated in step E37 of FIG. 4). The clutch 12 may be either in the engaged state or the disengaged state.

(5) Accumulation mode In the accumulation mode, the vehicle, that is, the rear wheels 1RL, 1R is in motion.
The motors ML and MR driven by R function as pumps to cause the accumulator 41 to accumulate pressure. In this pressure accumulation mode, the line 21L (21R) communicates with the reservoir tank 16 while the on-off valve VVF.L.
(VVF.R) is opened, and the oil liquid in the reservoir tank 16 is pumped up by the motor ML (MR) and accumulated in the accumulator 41.

(6) Stopping mode In the stopping mode, the motors ML and MR are arranged so as to stop the vehicle when the parking brake is not operating.
Is controlled (the driving of the motors ML and MR is controlled so that the vehicle speed becomes the target vehicle speed 0). In this case, the second supply line 31B is used as the hydraulic pressure supply line, and the hydraulic pressure supply / discharge control is performed by the switching valve VVB / L (VVB / L).
R) is used.

(7) Parking mode The parking mode enhances the action of maintaining the parking state when the parking brake is in operation. That is, in the parking mode, the switching valve VVB.L
(VVB · R) is set to the closed position of the central switching position to disconnect the hydraulic pressure supply / discharge line, and the clutch 12 is engaged.

(8) F / S mode The F / S mode is a fail-safe mode, and when there is some abnormality, for example, when the high pressure line becomes abnormally high pressure, it is a mode. -When the ML and MR are no longer driven normally, when a certain valve is stuck, and when the oil temperature rises above a predetermined temperature, the safety valve VVG is opened, The hydraulic pressure in the high pressure line 18 is released.

Description of Control System (FIG. 2) FIG. 2 shows a control system according to the present invention. In the figure, U1, U2, and U3 are control units configured by using a microcomputer, respectively.
Is a main control unit for controlling the above-mentioned valves VVA and the like. The control unit U2 is for ABS control (anti-lock brake control), and the control unit U3
Is for traction control. Further, S1 to S14 are
Each is a sensor or a switch.

The sensors S1 to S4 are used for the wheels 1FL to 1R, respectively.
The rotation speed of R, that is, the wheel speed is independently detected, and the wheel speed detected by each of the sensors S1 to S4 is transmitted from the control unit U2 to the control units U1 and U3. The sensor S5 detects the vehicle speed, and in the embodiment, detects the ground vehicle speed (absolute vehicle speed detection). The sensor S6 detects the shift position of the transmission 4, that is, the gear position. The sensor S7 detects the engine speed. The sensor S8 detects the steering angle of the steering wheel. The sensor S9 detects the accelerator opening. The sensor S10 detects the amount of depression of the brake pedal. The switch S11 is an ignition switch. The switch S12 detects whether or not the parking brake is activated.

The sensor S13 detects a bad road (uneven road). For the rough road detection, for example, the sensor S13 detects the vertical stroke of the suspension,
The control unit U1 determines that a bad road is generated when a predetermined amount of strokes or more occurs a predetermined number of times within a predetermined time. Further, the sensor S13 is used to detect the vertical G (acceleration) acting on the vehicle body, and the control unit U determines that the road is a bad road when it occurs a predetermined number of times or more within a predetermined time.
It may be configured such that 1 determines. The degree of bad road may be determined by changing one or more of the threshold values for the bad road determination.

The sensor S14 detects the lateral G acting on the vehicle body. Further, the switch S15 selects or changes the drive area of the motor (area in which the positive drive mode is executed) by manual operation. In the embodiment,
There are 3 types: "OFF" that forcibly prohibits the positive drive, "AUTO" that automatically determines whether or not to execute the positive drive, and "rapid acceleration" that allows the execution of the positive drive only during the sudden acceleration. One of the two is to be selected.

The signals from the sensors or switches S5 to S15 are input to the control unit U1, and the control unit U1 controls the above-mentioned valves VVA to VVJ. Of course, the control unit U2 is for preventing the wheels from being locked at the time of the brake, and the brake hydraulic pressure for individually adjusting the brakes of the respective wheels from the control unit U2. The adjusting means 81 is controlled. In addition, the control unit U3 includes the left and right front wheels 1F that are always driving wheels during acceleration or the like.
When the slip on the road surface of L, 1FR becomes excessive, at least the engine output (torque generated by the engine 2) is reduced. For example, the opening of the throttle valve of the engine 2, the ignition timing, the fuel injection amount, etc. The adjusting torque adjusting means 82 is controlled.

From the control unit U2 to the control unit U1, in addition to the wheel speed signals detected by the sensors S1 to S4, A
The ABS signal indicating that the BS control is being executed and the μ signal indicating the road surface μ (friction coefficient) are transmitted. Further, a wheel speed signal is transmitted from the control unit U2 to the control unit U3. Further, from the control unit U3 to the control unit U1, T indicating that the traction control is being executed is performed.
In addition to the RC signal, a torque reduction amount signal indicating the amount of engine torque reduction performed by the traction control and a road surface μ signal are transmitted. The road surface μ can be detected by the control unit U1, and the sensors S1 to S1.
Each wheel speed detected in S4 may be directly input to the control unit U1.

Description of Flow Chart (FIG. 3) Next, the control contents of the control unit U1 will be described with reference to the flow charts of FIG. In the following description, D, E, W, and Z indicate steps. First, in the main flow chart of FIG. 3, after signals from the respective sensors are input at D0, it is determined at D1 whether or not the ignition switch is OFF. When the determination in D1 is NO, in D2, it is determined whether or not the ignition switch is ON. If NO in this determination of D2, D3
At, the safety valve VVG is opened and the pressure in the high pressure line 18 is released. In addition, if D2 is determined, Y
At the time of ES, at D4, the safety valve VVG is closed and the high pressure hydraulic pressure is supplied to the high pressure line 18.

At D5, it is judged if the vehicle speed (vehicle speed to ground) is substantially zero. If YES in the determination of D5, it is determined in D6 whether the gear position of the transmission 4 is neutral. YE by the determination of D6
If S, then in D7, it is determined whether or not the parking brake is activated. When the determination in D7 is YES, the parking mode control is executed in D8. If the determination in D7 is no, in D9, control of the vehicle stop mode is executed.

If NO in D5 and NO in D6, the transmission 4 is set in D10.
It is determined whether or not the gear position of is the reverse position. D1
When the determination result in 0 is NO, in D11, it is determined whether or not the stack is currently in progress. Whether or not this is the stack is determined to be the stack, for example, when the accelerator is stepped on, the vehicle speed is almost 0, and the rotation speeds of the front left and right wheels 1FL, 1FR are sufficiently higher than the vehicle speed. Can be determined. When the determination in D11 is NO, it is determined in D12 whether the control mode other than the parking mode and the stop mode is to be performed, as described later. Then, in D13, a final determination is made as to whether to execute the control mode determined in D12.

If YES in the determination of D10, D
At 15, the drive assist utilizing the motors ML and MR is executed, but in this case, the normal drive is performed in the independent mode (the rear wheels 1RL and 1RR are driven in the backward direction). If YES in the determination of D11, in D14,
Drive assistance using motors ML and MR is executed,
In this case, the target vehicle speed is set to a low vehicle speed (for example, about 10 km / h, which is a stack release condition), and normal driving is performed in an independent mode described later.

If the determination in D1 is YES, then D16
After the clutch 16 is engaged at, the clutch engagement is maintained at D17 (the switching valve VVL is set to the line 6).
2 and 63 are both closed), and then at D18,
The safety valve VVG is opened.

Description of Flow Chart (FIGS. 4-9) Details of D12 in FIG. 3 are shown in the flow charts of FIGS. 4-9. First, at E23 in FIG.
It is determined whether or not the traction control by the control unit U3 is being performed. If NO in the determination in E23,
At E24, it is determined whether or not the vehicle is currently traveling on a rough road. When the determination in E24 is NO, in E25, it is determined whether or not the road surface is low μ. When the determination in E25 is NO, it is determined in E26 whether or not the vehicle is currently traveling straight ahead. In the embodiment, the determination as to whether or not the vehicle is going straight is performed in the lateral G direction based on the steering angle and the vehicle speed.
Is calculated to determine that the vehicle is traveling straight when the lateral G is equal to or less than a predetermined value.

When the result of E26 is YES, E27-
The processing of E39 is performed, but this processing is good road, high μ
It is based on the assumption that the road is straight ahead. And finally, the forward drive (E28) and the reverse drive (E28) in the integrated mode.
35), it is judged whether or not the control condition for accumulating the pressure mode (E33, E39) or the hydraulic lock mode (E31, E37) is satisfied.

The degree of acceleration and the degree of deceleration can be made by various known methods. For example, the degree of acceleration is
It can be known by any one or a plurality of combinations of the accelerator pedal depression speed, the accelerator pedal depression amount, the vehicle body acceleration obtained by differentiating the vehicle speed, and the like. The degree of deceleration is, for example, any one of the magnitude of accelerator release speed, the magnitude of brake depression speed, the increase amount of brake depression amount, and the vehicle body deceleration obtained by differentiating the vehicle speed. Alternatively, it can be known by an arbitrary plurality of combinations. However, in the embodiment, at least when the accelerator return speed is fast (the accelerator release speed is fast), it is determined that the deceleration is not less than the slow deceleration for the hydraulic lock mode.

If NO in the determination of E26 in FIG.
5 is performed, but FIG. 5 is premised on a good road, a high μ road, and during turning. Finally, it is determined whether or not the control conditions for performing the forward drive (E42) and the reverse drive (E44) or the LSD mode (E45) in the independent mode are satisfied.

If the determination at E25 in FIG. 3 is YES, the process shown in FIG. 6 is performed. In FIG. 6, first, E
At 51, it is determined whether or not the vehicle is traveling straight ahead. If YES in the determination of E51, the processes of E52 to E59 are performed, but this is a process on the premise that the road is a good road, a low μ road, and straight ahead. Finally, whether or not the control conditions for performing the forward drive (E55) and the reverse drive (E57) in the independent mode, the hydraulic lock mode (E54), and the LSD mode (E59) are satisfied is determined. To be judged.

When the determination at E51 in FIG. 6 is NO, the process shown in FIG. 7 is performed, but this process is a process on a good road, a low μ road, and when turning. Finally, it is determined whether or not the control conditions for performing the positive drive (E62), the hydraulic lock mode (E65) and the LSD mode (E66) in the independent mode are satisfied.

If the result of the determination at E24 in FIG. 4 is YES, the control mode during a bad road is executed in the processing after E71 in FIG.
In this bad road, the region (condition) in which the positive drive is performed in the independent mode is expanded as compared with the case of the good road.

Details of D13 in FIG. 3 are shown in FIG. In FIG. 9, the area for performing the positive drive is further limited. First, in W1, it is determined whether or not the determination result in D12 of FIG. 3 indicates that normal drive is performed. When the determination in W1 is NO, the control mode determined in D12 (control mode other than the positive drive such as the pressure accumulation mode) is executed in W2.

If YES in the determination of W1, W3
At, it is determined whether the actual lateral G detected by the sensor S14 is greater than or equal to a predetermined value. Y is determined by this determination of W3
In the case of ES, the execution of the positive drive is prohibited in W11 (it may be gradually prohibited). This is done from the viewpoint that, when the lateral G becomes large, it is preferable to control the attitude of the vehicle body by operating the steering wheel by the driver. However, from the viewpoint that it is preferable to improve the stability of the vehicle as four-wheel drive, it is possible to forcibly execute the positive drive in the independent mode when the determination in W3 is YES. .

When the determination in W3 is NO, it is determined whether or not the selected state of the manual switch S15 is "OFF" for inhibiting the forward drive. Even when the determination in W4 is YES, the forward drive is prohibited in W11.

When the determination in W4 is NO, in W5 it is determined where the current traveling state is in the region set by the vehicle speed and the steering angle as parameters. W
After step 5, it is determined in W6 whether or not the current traveling state is in the region X shown in W5. N is judged by this W6
When it is O, the positive drive is prohibited in W11.

If YES in the determination in W6, it is determined in W7 whether or not the manual switch selects "rapid acceleration". When the determination in W7 is NO, the positive drive is executed in W10. Also, W7
If YES in step S8, it is determined in W8 whether or not the vehicle is in rapid acceleration. When the vehicle is in rapid acceleration, the positive drive is executed in W10. When not in rapid acceleration, the normal drive is prohibited in W9. .

Description of Flow Chart (FIG. 10) FIG. 10 shows the details of the positive drive control in the independent mode. The forward drive control in the integrated mode differs only in that the same target vehicle speed is given to the left and right rear wheels.
Substantially the same as the positive drive control in the drive mode. First, after the data is input at Z1, the target vehicle speed VTR is set at Z2 using the accelerator opening and the gear shift position of the transmission 4 as parameters.

Next, at Z3, it is judged if the value obtained by subtracting the actual wheel speed VBL of the left rear wheel 1RL from the target vehicle speed VTR is greater than the predetermined speed V1. When the determination in Z3 is NO, it is determined that the drive assistance by the positive drive is not necessary, and the normal drive of the left rear wheel is stopped in Z13. The processes of Z3 and Z13 are performed independently for the right rear wheel 1RR and separately for the left rear wheel 1RL. The predetermined speed V1 is set to a speed indicating a slip amount sufficient for acceleration, but may be a constant value, or may be set to a variable value so that the vehicle speed VA increases as the vehicle speed VA increases. When the determination of Z3 is YES, it is determined whether or not the accelerator is fully closed in Z4, and when the determination of Z4 is YES, the motor M is also used.
Assuming that the driving assistance using L and MR is not necessary, the process proceeds to Z13 (in this case, the left and right rear wheels 1R).
L and 1RR simultaneously stop normal driving).

When the determination in Z4 is NO, the lateral G acting on the vehicle body is calculated in Z5 based on the vehicle speed VA and the steering angle of the steering wheel. After that, the correction coefficients k1 and k2 are set in Z6. Then, at Z7, it is determined whether or not the vehicle is making a right turn. If YES in the determination of Z7, the left rear wheel 1RL is set in Z9.
Target wheel speed VTRL of the target vehicle speed V determined by Z2
It is calculated by multiplying TR by the correction coefficient k1, and similarly, the target wheel speed VTRR of the right rear wheel 1RR is calculated by multiplying the target vehicle speed VTR by the correction coefficient k2.

If NO in Z7, the target wheel speeds of the left and right rear wheels 1RL, 1RR are calculated in Z8. After all, the processes of Z6 to Z9 correspond to the process of increasing the target wheel speed on the turning outer wheel side and slowing the target wheel speed on the turning inner wheel side. However, when going straight, the determination in Z7 is NO and the process shifts to Z8, but at this time, the correction coefficient is 1 (horizontal G is 0 or almost 0).
The target wheel speeds of the left and right rear wheels 1RL, 1RR are equal to each other).

After Z8 or Z9, at Z10, the rear wheel 1RL is changed from the target wheel speed VTRL (VTRR).
The amount of oil liquid Q supplied to the motor ML (MR) according to the value obtained by subtracting the actual wheel speed VBL (VBR) of (1RR)
Is determined. This oil quantity Q is determined by the left and right motors ML, M.
It is decided independently for R. Then, at Z11, the switching valves VVB · L and VVB · R are independently controlled so that the determined oil liquid amount Q is realized.

At Z12, it is judged if the value obtained by subtracting the actual wheel speed VBL of the left rear wheel 1RL from the vehicle speed VA is smaller than the predetermined speed "-V2". This Z
The determination of 12 is, after all, whether or not the actual wheel speed VBL of the left rear wheel 1RL is too large compared to the vehicle speed VA. When the determination of Z12 is YES, Z1 is determined.
In 3 so that the rear wheels maintain a predetermined slip value,
Correction is performed to reduce the supply flow rate Q. In addition, Z1
The processes of 2 and Z13 are similarly performed for the right rear wheel 1RR. If NO in Z12, Z13
Returned without going through.

In the positive drive control in the integrated mode, Z
The processing of 5 to Z9 becomes unnecessary, and the target vehicle speed VTR determined in Z2 is the target wheel speed VT of the left and right rear wheels 1RL and 1RR.
It becomes RL and VTRR. Further, the switching valve VVA is used to realize the flow rate Q at Z11.

Description of Flow Chart (FIG. 11) FIG. 11 shows details of reverse driving in the independent mode. In addition,
In the positive drive control in the integrated mode, the switching valve used for the flow rate adjustment is only different from the switching valve used in the independent mode, and the others are the same as the positive drive control in the independent mode. Done. First, after the data is input in Z21, it is determined in Z22 whether the reverse drive flag is 1 or not. If NO in this determination of Z22,
In Z30, the steering angle and the vehicle speed VA are set as parameters.
It is confirmed where the current state is in the area set as the data. Thereafter, in Z31, it is determined whether or not the current state is the hatched C area in the area shown in Z30. If YES in the determination of Z31, the reverse drive flag is set to 1 in Z32 and then the process returns to Z21. If NO in the determination of Z31, Z is determined.
Return to Z21 without going through 32.

After passing through Z32, the determination of Z22 is YE.
At S23, it is determined at Z23 whether ABS control is currently being performed. N is judged by this Z23
When it is O, it is determined in Z24 whether or not the brake depression amount is large. NO in this determination of Z25
At this time, the vehicle speed VA is set to the predetermined value V at Z25.
It is determined whether or not the vehicle speed is 3 or less.

If NO in Z25, Z2
6, the supply flow rate Q to the motors ML and MR is determined by using the vehicle speed VA and the shift position of the transmission 4 as parameters. Thereafter, in Z27, the switching valves VVB.L and VVB.R are controlled so that the flow rate Q determined in Z26 is supplied to the left and right motors ML and MR. Z2
After 7, the processing of Z28 and Z29 is performed. This processing corresponds to the processing of Z12 and Z13 in FIG. 9, and is processing for correcting the reverse driving force becoming too large.

When YES is determined in any of Z23, Z24 and Z25, the reverse drive control is stopped in Z33, and the reverse drive flag is reset to 0 in Z34. The reverse drive control in the integrated mode is Z26.
The VVA is used as a switching valve that realizes the flow rate Q determined in.

Flow chart (FIG. 12) FIG. 12 is executed when the determination at E23 in FIG. 4 is YES, and is a motor ML when the traction control is executed by the control unit U3. It is a drive assist control (independent right and left independent drive) control using MR.
First, after the data is input in Z41, the reduction amount of the torque applied to the front wheels 1FL, 1FR caused by the traction control of the control unit U3, that is, the torque reduction amount TF generated in the engine 2 is controlled in Z42. It is read based on the signal from unit U3. After this, Z4
In 3, the vehicle speed decrease amount VC corresponding to the torque decrease amount TF is determined.

At Z44, the supply flow rate Q to be supplied to the motors ML and MR is determined according to the vehicle speed reduction amount VC.
The supply flow rate Q is determined so that the total generated torque of the motors ML and MR becomes the same as the generated torque reduction amount of the engine 2. After that, in Z45, it is determined whether or not the traction control is stopped. When the determination of Z45 is NO, the processes of Z46 to Z52 are performed. The processing of Z46 to Z52 is performed by the correction coefficients F1 and F2.
Supply flow rate QTRL, QTR to the left and right rear wheels
R, that is, the torque distribution ratio is determined. More specifically, during turning, the torque distribution amount to the turning outer wheel side is made larger than the torque distribution amount to the turning inner wheel side (Z49,
Z51), the torque distribution ratio to the left and right rear wheels is made equal when going straight (Z52).

FIG. 49, after Z51 or Z52,
Although the processing from Z53 onward is performed, this processing corresponds to Z11 to Z13 in FIG.

Description of Flowchart (FIG. 13) FIG. 13 shows the control contents of the stop mode at D9 in FIG. First, after data is input in Z61, it is determined in Z62 whether or not the accelerator is depressed. If NO in the determination of Z62, Z
At 63, after the target vehicle speed VTR is set to 0,
In Z64, the supply flow rates to the motors ML and MR are adjusted so that the actual wheel speeds VBL or VBR of the left and right rear wheels 1RL and 1RR become the target vehicle speed VTR, respectively.
The feedback control is performed (right and left independent control).

By the way, when the transmission 4 is an automatic transmission (in this case, the clutch 3 is a torque converter), it is called a creep even if the accelerator is not depressed. It is designed to run at extremely low speeds. To obtain this creep, target vehicle speed V
If TR is set to, for example, 5 km / h, the creep speed can always be kept constant regardless of the inclination of the road surface while the vehicle is stopped. The target vehicle speed VTR can be manually selected, for example, in the range of about 0 to 15 km / h in a continuously variable manner or in a stepless manner (when the target vehicle speed is 0, no creep is made).

Although the embodiments have been described above, the present invention is not limited to this, and includes, for example, the following cases. (1) The left and right rear wheels 1RL, 1RR may be driven by the engine 2, and the left and right front wheels 1FL, 1FR may be driven by the motors ML, MR. (2) The motors ML and MR may be electric. (3) The motors may not be provided independently on the left and right, but may be only one on the left and right (a differential device is provided when auxiliary driving is performed by the motor even during turning).

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a hydraulic system used in the present invention.

FIG. 2 is a diagram showing an example of a control system.

FIG. 3 is a flow chart showing a control example of the present invention.

FIG. 4 is a flow chart showing a control example of the present invention.

FIG. 5 is a flow chart showing a control example of the present invention.

FIG. 6 is a flow chart showing a control example of the present invention.

FIG. 7 is a flow chart showing a control example of the present invention.

FIG. 8 is a flow chart showing a control example of the present invention.

FIG. 9 is a flow chart showing a control example of the present invention.

FIG. 10 is a flow chart showing a control example of the present invention.

FIG. 11 is a flow chart showing a control example of the present invention.

FIG. 12 is a flow chart showing a control example of the present invention.

FIG. 13 is a flow chart showing a control example of the present invention.

[Explanation of symbols]

U1: Control unit (for motor control) U2: Control unit (for ABS control) U3: Control unit (for traction control) P: Pump ML, MR: Motor 1FL, 1FR: Front wheel 1RL, 1RR: Rear wheel 2: Engine 4: Transmission 5: Differential device

Continuation of front page (56) Reference JP-A-2-175466 (JP, A) JP-A-63-149236 (JP, A) JP-A-2-120136 (JP, A) JP-A-63-101136 (JP , A) JP 63-195033 (JP, A) JP 2-120135 (JP, A) JP 63-203429 (JP, A) JP 1-249523 (JP, A) JP 2-200530 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60K 17/356

Claims (4)

(57) [Claims] 1. One of the left and right front wheels and the left and right rear wheels is a main drive wheel driven by an engine through a transmission and a differential device, and the other wheel is driven by a motor. In a vehicle with auxiliary drive wheels, the drive of the motor is driven so that the auxiliary drive wheels are driven in the same direction as the main drive wheels are driven by the engine only when a predetermined drive range is reached. Based on the drive control means for controlling and the lateral G acting on the vehicle body, the lateral G is a predetermined value or more.
Driving device for a vehicle, characterized in that sometimes and a driving area changing means for inhibiting driving of the motor that. 2. One of the left and right front wheels and the left and right rear wheels is a main drive wheel driven by an engine via a transmission and a differential device, and the other wheel is driven by a motor. In a vehicle with auxiliary drive wheels, the drive of the motor is driven so that the auxiliary drive wheels are driven in the same direction as the main drive wheels are driven by the engine only when a predetermined drive range is reached. Drive control means for performing control, wherein the drive region is set with the steering wheel steering angle and the vehicle speed as parameters, and the motor is driven in a low steering angle and low vehicle speed range to increase the steering angle. Alternatively, the vehicle drive device is set so that the drive of the motor is prohibited as the vehicle speed increases. 3. One of the left and right front wheels and the left and right rear wheels is a main drive wheel driven by an engine via a transmission and a differential device, and the other wheel is driven by a motor. In a vehicle with auxiliary drive wheels, the drive of the motor is driven so that the auxiliary drive wheels are driven in a direction opposite to the direction in which the engine drives the main drive wheels only when a predetermined drive range is reached. A drive device for a vehicle, comprising: drive control means for controlling; and drive area changing means for prohibiting reverse drive of the motor at low vehicle speeds. 4. One of the left and right front wheels and the left and right rear wheels is a main drive wheel driven by an engine via a transmission and a differential device, and the other wheel is driven by a motor. In a vehicle with auxiliary drive wheels, the drive of the motor is driven so that the auxiliary drive wheels are driven in the same direction as the main drive wheels are driven by the engine only when a predetermined drive range is reached. A drive device for a vehicle, comprising: drive control means for controlling; and drive area changing means for enlarging the drive area when the road is bad compared to when the road is good.