JPH06247165A - Drive device for vehicle - Google Patents

Abstract

PURPOSE:To enhance operability with the burden of vehicle occupants reduced, and concurrently shorten a free running distance by making the effect of braking variable, which is cased by engine brake at the time of urgent deceleration, with respect to a vehicle which has right and left front wheels driven by an engine, and has right and left rear wheels driven by hydraulic motors. CONSTITUTION:Motors MR and ML are so controlled as to apply the brake to rear wheels 1RR and 1RL, so that braking loas is made to be increased as compared with a case that the effect of enginebrake is obtained only by an engine 2.

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 in which an actuator such as a motor is used in addition to an engine to obtain a rotational driving force for wheels, and more particularly, an actuator assists the driving force. Regarding what you did.

[0002]

2. Description of the Related Art In recent years, four-wheel drive vehicles have been increasing in the form of driving vehicles because they have an advantage that the output of the engine can be appropriately distributed to all the wheels to reduce the slip of each wheel from the road surface. Tend to do. However, on the other hand, in a general four-wheel drive vehicle, for example, one in which the engine is arranged in the front part of the vehicle body, a propeller shaft or the like for transmitting the driving force of the engine to the rear wheels has a lower side of the floor panel. In order to secure this accommodation space, it is necessary to bulge the floor panel toward the inside of the vehicle, which may increase the weight of the vehicle body or the floor surface may become higher to reduce the vehicle interior space. There is a problem such as doing.

In order to solve these problems, conventional methods, for example, Japanese Patent Laid-Open Nos. 57-74222 and 63-38031 are used.
As disclosed in Japanese Patent Laid-Open No. 2-12036 and Japanese Patent Laid-Open No. 2-12036, one of the left and right front wheels or the left and right rear wheels is a main drive wheel driven by an engine, and the other is an auxiliary drive wheel driven by a motor. The vehicle drive device has been proposed.

That is, in the conventional example of Japanese Patent Application Laid-Open No. 57-74222, two hydraulic motors (hydraulic cylinders) on the left and right are provided.
It is disclosed that the function of the differential device is added by automatically distributing the hydraulic pressure supply to the vehicle according to the road surface load applied to the left and right auxiliary drive wheels.

Further, in the conventional example of Japanese Patent Laid-Open No. 63-38031, two electric motors on the left and right are used, and the generated voltage is increased as the vehicle speed increases so that the torque generated by the motor becomes constant. It is shown that the manual switch can be used to switch between drive execution and drive stop by the motor.

Further, Japanese Patent Application Laid-Open No. 2-12036 discloses a configuration in which the operating states of two hydraulic motors having different driving forces are switched according to the shift speed.

[0007]

By the way, in an ordinary vehicle, the wheels are drivingly connected to the engine. Therefore, when the braking force is obtained by the engine braking when the vehicle is decelerated, the magnitude of the braking force depends on the transmission. The braking load is determined by the rotational resistance of the engine when the throttle valve is closed, although the braking load varies depending on the gear position. Therefore,
For example, there is a limit in attempting to shorten the idling distance until the brake pedal is depressed by increasing the braking effect of the engine brake.

The present invention has been made in view of the above problems, and its main purpose is to use one of the left and right front wheels or rear wheels as a main drive wheel driven by an engine as described above, and the other as an actuator such as a motor. Focusing on a vehicle that uses auxiliary drive wheels driven by, and controlling the rotation of the auxiliary drive wheels enhances the braking effect of engine braking during vehicle deceleration, reducing the burden on the vehicle occupants and improving drivability. It is aimed at improving and at the same time being able to shorten the free-running distance.

[0009]

In order to achieve the above object, in the invention of claim 1, when the vehicle is decelerated, a braking load is applied to the wheels drivingly connected to the actuator by the actuator. .

Specifically, in the present invention, as shown in FIG. 1, the left and right front wheels 1FL, 1FR or the left and right rear wheels 1RL, 1FR are provided.
The first drive means 98 for driving one of the wheels 1FL, 1FR of the RR by the engine 2 and the other wheel 1RL, 1FR.
Second drive 1RR driven by actuators ML and MR
It is premised on a vehicle drive device including the drive means 99.

Then, the deceleration detecting means 100 for detecting the deceleration state of the vehicle, and the actuator ML, when the deceleration state of the vehicle is detected by the deceleration detecting means 100.
A control means 102 for controlling the second drive means 99 so that the MR applies a braking load to the wheels 1RL, 1RR is provided.

According to a second aspect of the present invention, in the vehicle drive system of the first aspect, a driving state detecting means 101 for detecting the driving state of the vehicle is provided, and the control means 102 controls the wheels 1RL, 1RR by the actuators ML, MR. The braking load is variable according to the driving state of the vehicle detected by the driving state detecting means 101.

According to the third aspect of the present invention, the operating state detecting means 101 detects the shift speed of the transmission 4 as the operating state of the vehicle, and the control means 102 controls the actuator as the shift speed of the transmission 4 decreases. Wheel 1R by ML and MR
It is configured to increase the braking load on L and 1RR.

According to the invention of claim 4, the operating state detecting means 1
01 is for detecting that the foot brake pedal is depressed as the driving state of the vehicle, and the control means 102
Is configured to increase the braking load on the wheels 1RL and 1RR by the actuators ML and MR when the foot brake pedal is depressed.

According to the invention of claim 5, the operating state detecting means 1
Reference numeral 01 denotes the accelerator pedal return speed as the operating state of the vehicle, and the control means 102 applies the braking load on the wheels 1RL, 1RR by the actuators ML, MR when the accelerator pedal return speed is equal to or higher than a predetermined value. Configure to increase.

[0016]

With the above construction, in the invention of claim 1, when the vehicle is in the decelerating state, this is detected by the deceleration detecting means 100, and at the time of detecting the deceleration, the control means 102 causes the actuators ML, MR to move the wheels 1RL, The second drive means 99 is controlled so as to apply a braking load to 1RR. In this way, the second driving means 99 operates independently of the first driving means 98 that uses the output of the engine 2 as the wheel driving force, and the actuator ML of the second driving means 99,
A braking load is applied to the wheels 1RL and 1RR by the MR. Therefore, if the braking load characteristics of the actuators ML and MR are changed, a variety of engine brakes can be obtained as compared with the case where the engine 2 of the first drive means 98 produces an engine braking effect. The effect can be obtained, and for example, by increasing the braking load, the idling distance until the brake pedal is depressed can be shortened, and the vehicle braking distance can be shortened. Further, since the engine braking effect by the actuators ML and MR is automatically added when the vehicle is decelerated, the load on the occupant can be reduced and the drivability of the vehicle can be improved.

According to the second aspect of the invention, the driving state of the vehicle is detected by the driving state detecting means 101, and the wheels 1RL, 1RR by the actuators ML, MR are detected according to the driving state of the vehicle detected by the driving state detecting means 101. The braking load for is variable. In this way, the braking load by the actuators ML, MR changes according to the driving state of the vehicle, so that the overall engine braking characteristic to which the braking load by the actuators ML, MR is added becomes an appropriate characteristic according to the driving state of the vehicle. can do.

According to the third aspect of the present invention, the gear shift stage of the transmission 4 is detected as the driving state of the vehicle by the driving state detection means 101, and the lower the gear shift stage of the transmission 4 by the control means 102, the actuator ML, Wheel 1 by MR
The braking load on RL and 1RR is controlled to increase. Therefore, an appropriate engine braking characteristic according to the gear stage of the transmission 4 can be obtained.

In the fourth aspect of the present invention, the operation state detecting means 101 detects that the foot brake pedal has been depressed as the operation state of the vehicle, and the control means 102 uses the actuators ML and MR when the foot brake pedal is depressed. The braking load on the wheels 1RL, 1RR is increased. That is, when the foot brake pedal is depressed, a large braking force is required, so that an appropriate engine braking characteristic can be obtained.

According to the fifth aspect of the present invention, as the driving state of the vehicle, the return speed of the accelerator pedal is the driving state detecting means 101.
The control unit 102 increases the braking load applied to the wheels 1RL, 1RR by the actuators ML, MR when the return speed of the accelerator pedal is equal to or higher than a predetermined value. That is, when the accelerator pedal return speed is high, a large braking force is required accordingly, so that appropriate engine braking characteristics can be obtained.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. The procedure of the description will be described in the order of the configuration of the hydraulic system, each control mode, the control system, and each control flowchart.

[Explanation of hydraulic system (see FIG. 2)] In FIG. 2, 1FL is the left front wheel of the vehicle, 1FR is the right front wheel, 1R
L is the left rear wheel, and 1RR is the right rear wheel. An engine 2 is arranged in a horizontal position at a front portion of a vehicle body, and a driving force of the engine 2, that is, a generated torque, is transmitted to a differential device 5 through a clutch 3 and a manual transmission 4 having five forward gears and one reverse gear. To be done. Further, the driving force of the engine 2 is transmitted from the differential device 5 to the left front wheel 1FL via the left drive shaft 6L and to the right front wheel 1FR via the right drive shaft 6R. That is, the clutch 3, the transmission 4, the differential device 5, and the shafts 6L, 6R constitute a first drive means 98 for driving the left and right front wheels 1FL, 1FR by the engine 2.

Further, the left and right front wheels 1FL, which serve as steering wheels,
The 1FRs are linked to each other by a steering link 7 such as a tie rod, and this steering link 7 is linked to a steering wheel 8 via a rack and pinion mechanism 9.

On the other hand, the left and right rear wheels 1RL, 1RR are driven independently of the engine 2 by a pair of left and right hydraulic motors ML, MR. That is,
The left rear wheel 1RL is driven by a left motor ML as a rear wheel drive actuator via a left drive shaft 11L, and the right rear wheel 1RR is driven by a right motor MR as a similar actuator via a right drive shaft 11R. It is like this. The left motor ML, that is, the left drive shaft 11L and the right 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. Then, the left and right drive shafts 11
The L and 11R can be connected and disconnected by a hydraulic clutch 12. That is, the left rear wheel 1 is driven by the hydraulic system.
The second driving means 99 is configured to drive the RL and 1RR by the motors ML and MR (actuators).

The motor ML (MR) is of a turbine type (impeller type) and has a first connection port La (Ra) and a second connection port Lb (Rb), respectively, and a first connection port La (R).
When the high-pressure hydraulic oil flows from a) to the second connection port Lb (Rb), the high-speed hydraulic oil rotates in the forward direction, and when the high-pressure hydraulic oil flows in the opposite direction, the reverse rotation occurs. The motors ML and MR have the same specifications, and the total value of the maximum generated torque is 1/3 of the maximum generated torque of the engine 2.
It is set to about 1/2.

In this 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 1 by the engine 2
Left and right rear wheels 1R even when FL and 1FR are driven
In some cases, L and 1RR are not driven by the motors ML and MR.

Reference numeral P is a variable displacement pump as a hydraulic pressure source, and the pump P is drivingly connected to the output shaft 2a of the engine 2 via a drive pulley 13, a belt 14 and a driven pulley 15. That is, the pump P constitutes an energy generating unit that is driven by the engine 2 to generate hydraulic pressure as drive energy for the motors ML and MR. The high-pressure hydraulic oil pumped up from the reservoir tank 16 by the pump P is discharged to the high-pressure line 18 provided with the check valve 17. In this high pressure line 18,
First and second hydraulic pressure supply lines 31A and 31B, which are provided with check valves 10 and 32 and are parallel to each other, are connected. Further, a release line 23 is connected to the reservoir tank 16. Further, lines 20 parallel to each other are provided at the connection ports La and Lb (Ra and Rb) of the motor ML (MR).
L, 21L (20R, 21R) are connected.

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

A switching valve VVI is connected downstream of the check valve 32 and a diversion valve 34 is connected downstream of the switching valve VVI to the second hydraulic pressure supply line 31B. One branch supply line 33L branched into two by the branch valve 34 is connected to the line 19L, and the other branch supply line 33R is connected to the line 19R.
It is connected to the.

The high-voltage line 18 is connected to the motors ML and M.
Accumulator 4 as an energy storage means for storing high-pressure hydraulic pressure as driving energy for R
1 is connected. The line 20L (20R) is connected to the high pressure line 18 by a passage 42L (42R). In this passage 42L (42R), there is a check valve 43L (43R) and a switching valve VVF.L (VVF.
R) is provided. Both passages 42L and 42R are in parallel with each other, and each of the above-mentioned valves VVA, VVB.L (VVB.
R), VVE / L (VVE / R), VVI and the shunt valve 34
It is bypassing etc.

The line 20L (20R) and the line 21
The communication passage 51L (51R) communicates with L (21R), and the variable orifice VVC · L (VVC · R) is arranged in the communication passage 51L (51R).

Reference numeral 61 is an actuator for connecting and disconnecting the clutch 12. The supply line 62 for the actuator 61 is for the high pressure line 18, and the discharge line 63 is for the release line 23.
It is possible to connect selectively by using J, and the switching valve V
Both lines 62 and 63 can be blocked by VJ.

A communication passage 71 is provided between the left and right motors ML and MR.
An on-off valve VVD is arranged in the communication passage 71.

The release line 23 is connected to the high-pressure line 18 via the load / unload valve VVH on the upstream side (pump P side) of the check valve 17 and via the safety valve VVG on the downstream side of the check valve 17. Are connected to each other.

[Explanation of Control Modes (Table 1)] This embodiment has a total of eight types of control modes, as will be described later, and shows the operating states of the respective valves when each mode is executed. Collectively shown in Table 1. In Table 1, 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 the lower limit value and the upper current value.

[0037]

[Table 1]

In the respective control modes shown in Table 1, the operating states of the valve which performs the main function will be specifically described.
It is as follows.

(1) Integrated mode The integrated mode is used for the left and right rear wheels 1RL, 1 as will be described later.
The drive control of the motors ML and MR is performed so that the RR has the same number of rotations, and there are two types: forward 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
The operation modes of (VVB / R), VVE / L (VVE / R), and VVI are the states shown in FIG. In this state, the switching valve VVA is controlled so that the switching of the hydraulic pressure supply direction according to the forward drive or the reverse drive (the forward / reverse direction setting of the motors ML and MR) and the supply flow rate to the motors ML and MR are performed. Controlled (hydraulic pressure supply using the first supply line 31A).

In the reverse drive, a deceleration force larger than that in the hydraulic lock mode described later is obtained. However, as a matter of course, when the vehicle is moving forward, the rear wheels 1RL,
1RR does not give a large driving force such that the 1RR rotates in a direction opposite to the traveling direction of the vehicle.
The braking force is applied to the RR.

(2) Independent mode In the independent mode, the left and right rear wheels 1RL, 1R are described in detail later.
The drive control of the motors ML and MR is performed so that each R has a target wheel speed that is independently set. As in the case of the integrated mode described above, there are two types of forward drive and reverse drive.
There are types. Further, 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 (V
The operation mode of (VE / R) is set to the state shown in FIG. 2, but the switching valve VVA is set to the central switching position and the first hydraulic pressure supply line 31A is shut off. The switching valve VVI is in the open position, and is in the hydraulic pressure supply mode using the second hydraulic pressure supply line 31B. In this state, the switching valve VVB ・ L (VVB ・ L
R) is controlled to switch the hydraulic pressure supply direction according to the forward drive or the reverse drive (setting of the forward and reverse directions of the motors ML and MR) and the supply flow rate to the motors ML and MR.

(3) LSD mode The LSD mode obtains a differential limiting function, and is a switching valve VV.
B / L and VVB / R are lines 20L and 21L (20R,
21R) are closed together to completely cut off the supply and discharge of hydraulic pressure to and from the motors ML and MR. Then, the on-off valve VVD is opened to communicate the closed left and right hydraulic paths of the two motors ML9MR with each other, and the left and right motors ML, M are connected.
It prevents a large rotation difference between Rs. In this LSD mode, the variable orifice VVC ・ L
(VVC / R) is fully closed.

(4) Hydraulic Lock Mode In the hydraulic lock mode, the passage resistance, that is, the 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
Line 2 with VB / L and VVB / R in the central switching position
0L, 21L, 20R, 21R are shut off, the on-off valve VVD is closed, and variable orifices VVC.L, V
VC ・ R is opened. In this state, the hydraulic oil is the motor M
Variable orifice VVC ・ L depending on the rotation of L (MR)
(VVC · R) is circulated in a closed hydraulic circuit that is closed, but the throttle resistance of the variable orifice VVC · L (VVC · R) through which the hydraulic oil passes during the circulation is the vehicle. Will give a deceleration force to. Then, the opening amounts of the variable orifices VVC · L, VVC · R are controlled so as to decrease as the vehicle deceleration increases (the opening amounts of the variable orifices VVC · L, VVC · R are set according to the deceleration). (It is illustrated in step E37 of FIG. 5). still,
The clutch 12 may be in the engaged state or the disengaged state.

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

(6) Vehicle Stop Mode In the vehicle stop mode, the motors ML and MR are drive-controlled so as to stop the vehicle when the parking brake is not operated (the vehicle speed becomes the target vehicle speed "0"). The drive of the motors ML and MR is controlled). In this case, the second hydraulic pressure supply line 31B is used as the hydraulic pressure supply line, and the switching valve VVB.L (VVB.
R) is used.

(7) Parking Mode The parking mode enhances the action of maintaining the parking state when the parking brake is operated. That is, in the parking mode, the switching valve VVB · L (V
(VB / R) is set to the closed position of the central switching position to cut off 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 voltage line 18 becomes abnormally high, the motors ML and MR are driven normally. The safety valve VVG is opened to release the hydraulic pressure in the high-pressure line 18 when the valve is no longer operated, a certain valve is stuck, or when the oil temperature becomes higher than a predetermined temperature.

[Description of Control System (See FIG. 3)] FIG. 3 shows a control system according to the present invention. In the figure, U1 to U3 are control units each incorporating a microcomputer,
The control unit U1 is a main control unit that controls the above-described valves VVA and the like. The control unit U2 is for ABS control (antilock brake control), and the control unit U3 is for traction control. further,
S1 to S10 and S14 are sensors, S11 to S1 respectively.
Reference numerals 3 are switches, respectively.

Each of the sensors S1 to S4 has a wheel 1F.
The rotation speeds of L to 1RR, that is, the wheel speeds are independently detected, and the wheel speed signals detected by the sensors S1 to S4 are transmitted from the control unit U2 to the control units U1 and U.
3 is transmitted. The sensor S5 detects the vehicle speed,
In this embodiment, the ground vehicle speed is detected (absolute vehicle speed detection).
The sensor S6 is a shift speed sensor for detecting the shift speed of the transmission 4, the sensor S7 is the engine speed, and the sensor S8.
Is for detecting the steering angle of the steering wheel 8, which is the steering angle. The sensor S9 is an accelerator opening sensor that detects the depression amount of the accelerator pedal, that is, the accelerator opening. The sensor S10 is a foot brake depression sensor that detects the depression amount of the foot brake pedal. The switch S11 is an ignition key switch, and the switch S12 is for detecting whether or not the parking brake is operated.

The switch S13 is a manual switch,
"AUTO", "Integrated control", "Independent control" and "OF"
Four control modes of "F" are selected. Sensor S
Reference numeral 14 denotes a bad road (uneven road). For example, when the sensor S14 detects a vertical stroke of the suspension and a stroke of a predetermined amount or more occurs a predetermined number of times within a predetermined time, it is determined as a bad road. Main control unit U
1 determines. In addition, the main control unit U1 determines that the sensor S14 detects up and down G (acceleration) acting on the vehicle body and that the up and down G above a predetermined number occurs a predetermined number of times or more within a predetermined time as a bad road. It can also be configured to. The degree of bad road may be determined by changing one or more of the threshold values for the bad road determination.

The signals from the sensors and the switches S5 to S14 are input to the main control unit U1, which controls the valves VVA to VVJ described above. Of course, the control unit U2 has wheels 1F when braking.
The control unit U2 controls the brake fluid pressure adjusting means 81 for individually adjusting the brakes of the wheels 1FL to 1RR for preventing the lock of the L to 1RR. The control unit U3 reduces at least the engine output (torque generated by the engine 2) when the left and right front wheels 1FL and 1FR, which are constantly driving wheels, slip excessively on the road surface during acceleration or the like. The torque adjusting means 82 for adjusting the opening of the throttle valve of the engine 2, the ignition timing, the fuel injection amount, etc. is controlled.

From the control unit U2 to the main control unit U1, in addition to the wheel speed signals detected by the sensors S1 to S4, the ABS signal indicating that ABS control is being executed and the road surface μ (friction coefficient) are indicated. and the μ signal is 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 main control unit U1, in addition to the TRC signal indicating that the traction control is being executed, the torque reduction amount signal indicating the reduction amount of the engine torque performed by the traction control, and the road surface μ signal. Is transmitted. The road surface μ can be detected by the main control unit U1,
Further, the wheel speeds detected by the sensors S1 to S4 may be directly input to the main control unit U1.

[Description of Main Control (See FIG. 4)] Next,
The control content of the main control unit U1 will be described with reference to the flowcharts in FIG. First, Figure 4
The main flow chart of the above will be described. In this main flow chart, first, in step D0, the signals from the respective sensors are input, and then in step D
At 1, it is determined whether or not the ignition switch S11 is in the OFF state. If it is determined NO in step D1 that the ignition switch S11 is not in the OFF state, it is determined in step D2 whether the ignition switch S11 is in the ON state, and in step D2 it is determined that the ignition switch S11 is not in the ON state. If so, the routine proceeds to step D3, where the safety valve VVG is opened and the pressure in the high pressure line 18 is released. Further, when it is determined YES in step D2 that the ignition switch S11 is in the ON state, the safety valve VVG is closed in step D4 so that the high pressure hydraulic pressure is supplied to the high pressure line 18.

Then, in step D5, it is determined whether or not the vehicle speed (ground vehicle speed) detected by the vehicle speed sensor S5 is substantially zero. When it is determined to be YES in step D5, that is, the vehicle speed is substantially zero, it is determined in step D6 whether the gear position of the transmission 4 is neutral by the detection of the gear position detection sensor S6. In step D6, the gear position of the transmission 4 is Y, which is neutral.
When it is determined to be ES, it is determined in step D7 whether or not the parking brake is operated by the detection of the parking brake detection switch S12. The parking brake is activated in step D7.
When it is determined to be ES, the control of the parking mode as described above is executed in step D8 so that the maintenance performance of the parking state of the vehicle is enhanced. If it is determined NO in step D7 that the parking brake is not operating, the control in the vehicle stop mode as described above is executed in step D9 to control the vehicle speed to zero.

On the other hand, when it is determined that the vehicle speed is not substantially 0 in step D5, that is, when the vehicle is traveling, or when it is determined in step D6 that the gear position of the transmission 4 is not neutral, NO. Is step D1
At 0, it is determined whether the gear position of the transmission 4 is the reverse position. If it is determined in step D10 that the gear position of the transmission 4 is not the reverse position, step D
At 11, it is determined whether the stack is currently in progress.
Whether or not the vehicle is in this stack is determined by, for example, detecting the accelerator opening detection sensor S9, which is operating the accelerator pedal, the vehicle speed is substantially zero, and the wheel speed sensors S1 to S4.
When the rotational speeds of the left and right front wheels 1FL and 1FR detected by are higher than the vehicle speed, it is determined that the vehicle is in a stack. Then, if it is determined to be NO in the stack in step D11, in step D12,
It is determined whether or not a control condition for performing a parking mode and a control mode other than the stop mode as described below is satisfied, and then, in step D13, control execution / execution is performed by a control mode execution determination as described below. Perform non-execution.

When it is judged YES in step D10 that the gear position of the transmission 4 is in the reverse position, the driving using the motors ML and MR is executed in step D15. In this case, the independent mode is selected. In reverse (driving the rear wheels 1RL, 1RR in the backward direction).
The details of the backward movement will be described later.

When it is judged YES in step D11 that the vehicle is stuck, drive assistance using the motors ML and MR is executed in step D14. In this case, the target vehicle speed is set to a low vehicle speed (for example, stack release). The positive drive is performed in the independent mode described later, which is set to about 10 km / h, which is the condition.

Further, when it is judged YES in step D1 that the ignition switch is in the OFF state, the clutch 12 is engaged in step D16, and the clutch engagement is maintained in step D17 (the switching valve VVJ is set to the line 62). , 63 together),
Then, in step D18, the safety valve VVG is opened.

[Explanation of Mode Judgment Control (see FIGS. 5 to 8)] Next, a judgment operation of whether or not the control condition for performing the control mode of step D12 in the above-mentioned main flow chart (see FIG. 4) is satisfied. Details will be described based on the mode determination flowcharts of FIGS. This mode determination flowchart is based on the premise that the road is not a good road, that is, a bad road. First, in step E24 of FIG. 5, it is determined whether or not the traction control by the control unit U3 is currently being performed. When NO is determined in step E24 that the traction control is not being performed, it is determined in step E25 whether or not the road surface is low μ, and when it is determined NO in step E25, the road surface is not low μ. At E26, it is determined whether the vehicle is currently traveling straight. In this embodiment, the determination as to whether or not the vehicle is going straight is performed by calculating the lateral G based on the steering wheel steering angle detected by the steering wheel steering angle sensor S8 and the vehicle speed detected by the vehicle speed sensor S5. When it is less than the value, it is determined that the vehicle is traveling straight ahead.

When it is judged YES in step E26 that the vehicle is traveling straight ahead, steps E27 to E39 are executed.
Process. This treatment is based on the premise that the road is a good road, a high μ road, and straight ahead, and finally, the forward drive (step E28) and the reverse drive (step E35) in the integrated mode, and the pressure accumulation mode (steps E33, E39). Alternatively, it is determined whether or not the control conditions for performing the hydraulic lock mode (steps E31 and E37) are satisfied. Specifically, step E2
In step 7, it is determined whether or not the vehicle is in the rapid acceleration operation state, and when it is determined as YES in the step E27, which is in the rapid acceleration operation state, it is determined in step E28 that the condition for the positive drive in the integrated mode is satisfied. That is, the driving force is assisted by driving the rear wheels 1RL and 1RR in the forward direction when the vehicle runs straight on a high μ road and is suddenly accelerated.

When it is determined NO in step E27 which is not the rapid acceleration operation state, it is determined in step E29 whether or not the vehicle is in the high speed operation state, and when it is determined NO in the step E29 which is not in the high speed operation state. In step E30, it is determined whether or not the vehicle is in the slow deceleration operation state. When it is determined to be YES in the slow deceleration operation state in step E30, it is determined in step E31 that the hydraulic lock mode condition is satisfied.
That is, when the vehicle runs straight on the high μ road and is slowly decelerated in the medium-low speed operation state, the deceleration force is slightly increased by giving a resistance to the rotation of the rear wheels 1RL and 1RR.

On the other hand, when it is judged NO in the slow deceleration operation state in the above step E30, it is judged in step E32 whether or not it is in the rapid deceleration operation state, and in step E32 it is judged YES in the rapid deceleration operation state. If so, it is determined in step E33 that the condition of the pressure accumulation mode is satisfied. That is, the rear wheels 1RL and 1RL, 1
While giving resistance to the rotation of RR, this rear wheel 1RL, 1R
The rotation of R is used to accumulate pressure in the accumulator 41.

Further, when it is judged YES in the high speed operation state in step E29, step E34
In step E34, it is determined that the reverse driving condition in the integrated mode is satisfied if it is determined YES in step E34. In other words, when the vehicle runs straight on a high μ road and also during rapid deceleration during high-speed operation, the rear wheel 1
The deceleration force is increased by applying a large braking force to the rotations of RL and 1RR.

On the other hand, if it is determined NO in step E34, which is not the sudden deceleration operation state, it is determined in step E36 whether the vehicle is in the slow deceleration operation state. In step E36, it is determined that the vehicle is in the slow deceleration operation state. If so, it is determined in step E37 that the hydraulic lock mode condition is satisfied, and the opening of the variable orifice VVC is set according to the deceleration. That is, high μ
When going straight on the road and slowing down during high speed operation,
The deceleration force is slightly increased by giving the resistance corresponding to the deceleration to the rotation of the rear wheels 1RL and 1RR.

When it is determined NO in the slow deceleration operation state in step E36, it is determined in step E38 whether the vehicle is in the steady operation state, and in step E38 it is determined that the steady operation state is YES. At step E39, it is determined that the pressure accumulation mode condition is satisfied. That is, when the vehicle runs straight on a high μ road and is stationary in a high-speed operating state, the pressure is accumulated in the accumulator 41 by utilizing the rotation of the rear wheels 1RL and 1RR.

Further, the above step E32 and step E
When NO is determined in 38, the operation mode is not established, and the process ends. That is, the rear wheels 1RL and 1RR are not driven during a steady state in the medium-low speed operation state.

The degree of acceleration and the degree of deceleration as described above can be made by various known methods. That is, the degree of acceleration can be known by any one of 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. In addition, the degree of deceleration, for example, the magnitude of the accelerator release speed, the magnitude of the brake depression speed,
It can be known from any one of the increase amount of the brake depression amount, the vehicle body deceleration obtained by differentiating the vehicle speed, or any combination thereof.

Then, the above step E26 (see FIG. 5).
When it is determined to be NO in the straight running state, the process of FIG. 6 is performed, but the process of FIG. 6 is premised on a good road, a high μ road and turning. Then, finally, it is determined whether or not the control conditions for performing the forward drive (step E42) and the reverse drive (step E44) in the independent mode or the LSD mode (step E45) are satisfied. Specifically, in step E41, it is determined whether or not the vehicle is in the rapid acceleration operation state, and when YES is determined in step E41, which is the rapid acceleration operation state, the condition for the positive drive in the independent mode is in step E42. Judge that it has been established.
That is, at the time of sudden acceleration accompanied by turning on a high μ road, the rear wheels 1RL,
By independently driving the 1RR in the normal direction, the turning drive force is assisted.

If it is determined NO in step E41, which is not the rapid acceleration operation state, it is determined in step E43 whether the vehicle is in the deceleration operation state. When it is determined to be YES in the decelerating operation state in step E43, it is determined in step E44 that the reverse driving condition in the independent mode is satisfied. That is, the deceleration force is increased by applying a large independent braking force to the rear wheels 1RL and 1RR during deceleration accompanied by a turn on a high μ road.

On the other hand, when it is judged NO in step E43 which is not the decelerating operation state, it is judged in step E45 that the condition of the LSD mode is satisfied. That is, when turning without acceleration / deceleration on a high μ road, the left and right rear wheels 1RL, 1
Smooth turning is performed while suppressing the occurrence of a large rotation difference in RR.

Further, the above step E25 (see FIG. 5).
When it is determined that the road surface is low μ in YES, the processing shown in FIG. 7 is performed. In the process of FIG. 7, first, at step E51, it is determined whether the vehicle is traveling straight ahead. When it is determined to be YES when the vehicle is traveling straight in this step E51, the processing of steps E52 to E59 is performed, which is a processing on the condition of a straight road and a low μ road. Finally, the positive drive in the independent mode (step E5
5) and reverse drive (step E57), hydraulic lock mode (step E54), LSD mode (step E59)
It is determined whether the control condition for performing is satisfied. Specifically, it is determined in step E52 whether or not the vehicle is in the high speed operation state, and in step E52, the high speed operation state is Y.
When it is determined to be ES, it is determined in step E53 whether or not the vehicle is in the deceleration operation state.
If it is determined to be YES in the deceleration operation state in step S54, it is determined in step E54 that the hydraulic lock mode condition is satisfied. That is, the deceleration force is slightly increased by imparting resistance to the rotation of the rear wheels 1RL and 1RR during straight traveling on a low μ road and during deceleration from the high speed operation state.

If it is determined NO in step E53, which is not in the decelerating operation state, it is determined in step E55 that the condition for the positive drive in the independent mode is satisfied. In other words, the rear wheels 1 when driving straight on a low μ road and driving at high speed
The driving force is assisted by independently driving the RL and 1RR in the forward direction.

On the other hand, when it is judged NO in step E52 which is not the high speed operation state, it is judged in step E56 whether or not it is in the rapid acceleration operation state, and in step E56 it is judged YES in the rapid acceleration operation state. If so, it is determined in step E57 that the condition for the positive drive in the independent mode is satisfied. That is, by driving the rear wheels 1RL and 1RR independently in the forward direction even when the vehicle runs straight on a low μ road and is suddenly accelerated from a stopped state or a medium or low speed operation state,
The driving force is assisted.

When it is determined NO at step E56 which is not in the rapid acceleration operation state, it is determined at step E58 whether or not it is in the deceleration operation state. When it is determined at step E58 that it is not NO in the deceleration operation state. , At step E59, it is determined that the LSD mode condition is satisfied. That is, stable traveling is performed while suppressing the occurrence of a large rotation difference between the left and right rear wheels 1RL and 1RR during straight traveling without acceleration / deceleration on a low μ road.

When the determination in step E58 is YES, the operation mode is not established and the process ends.

If it is determined at step E51 (see FIG. 7) that the vehicle is not in the straight running state, the process shown in FIG. 8 is performed. This process is a process on a good road, a low μ road, and on the assumption that the vehicle is turning, and finally, the positive drive in the independent mode (step E62) and the hydraulic lock mode (step E).
65), it is determined whether the control condition for performing the LSD mode (step E66) is satisfied. Specifically, in step E61, it is determined whether or not the vehicle is in the sudden acceleration operation state,
When it is determined to be YES in the rapid acceleration operation state in step E61, it is determined in step E62 that the condition for the positive drive in the independent mode is satisfied. That is, low μ
At the time of sudden acceleration accompanied by turning on the road, the rear wheels 1RL and 1RR are independently driven to rotate normally to assist the turning driving force.

On the other hand, when it is judged NO in step E61 which is not the rapid acceleration operation state, it is judged in step E63 whether or not it is in the high speed operation state, and in step E63 it is judged YES in the high speed operation state. At step E64, it is determined whether or not the vehicle is in the deceleration operation state. When it is determined YES at step E64 that the vehicle is in the deceleration operation state, it is determined that the hydraulic lock mode condition is satisfied. That is, the deceleration force is slightly increased by giving a resistance to the rotation of the rear wheels 1RL and 1RR during deceleration from high speed operation accompanied by turning on a low μ road.

When it is determined in step E64 that NO is not in the decelerating operation state, or when it is determined in step E63 that it is not in high speed operation, it is determined in step E66 that the LSD mode condition is satisfied. That is, during high-speed operation accompanied by turning without acceleration / deceleration on a low μ road or during medium-low speed operation, smooth turning is performed while suppressing the occurrence of a large rotation difference between the left and right rear wheels 1RL, 1RR.

[Description of Execution Judgment Control (see FIG. 9)] Next, the control content of step D13 in the above-mentioned main flowchart (see FIG. 4) will be described with reference to FIG. The process of FIG. 9 is for finally executing and not executing the mode that satisfies the control conditions of FIGS. 5 to 8 described above.

First, in step W0, it is determined whether or not the control conditions for performing the control modes other than the integrated mode and the independent mode are satisfied. When it is judged YES in step W0 that the control condition for performing the control mode other than the integrated mode and the independent mode is satisfied, the control mode satisfying the control condition is executed in step W4 (LSD).
Mode, hydraulic lock mode, accumulator mode).

When it is determined in step W0 that the control condition for performing the integrated mode or the independent mode is NO, the operation state (selected state) of the manual switch S13 is "OFF" in step W1. Or not. If the operation state of the manual switch S13 is YES in step W1, it is determined that the driver does not desire drive assistance using the motors ML and MR, and step W
Proceeding to 2, the drive assist using the motors ML and MR is prohibited (not executed).

On the other hand, if it is determined in step W1 that the operation state of the manual switch S13 is not "OFF", then the manual switch S1 is determined in step W3.
It is determined whether the operation state of No. 3 is "AUTO".
When it is determined in step W3 that the operation state of the manual switch S13 is "AUTO", that is, when YES is determined, in step W4, the control mode satisfying the control conditions is executed including the driving assistance by the motors ML and MR. .

When it is determined in step W3 that the operation state of the manual switch S13 is not "AUTO", that is, NO, it is determined in step W5 whether the control conditions in the integrated mode are satisfied. This step W
If it is determined YES in 5 that the control condition in the integrated mode is satisfied, it is determined in step W6 whether or not the operation state of the manual switch S13 is the "integrated mode" selection. In step W6, the operation state of the manual switch S13 is “integrated mode” selection YES
If it is determined that the road is a bad road in step W7, it is determined in step W7 that the road is not a bad road.
When it is determined to be O, the motors ML and MR are driven in the integrated mode in step W8.

When it is determined in step W6 that the operation state of the manual switch S13 is not "integrated mode" selection, or when it is determined in step W7 that the road is a bad road YE.
When it is determined to be S, the motors ML and MR are driven in the independent mode in step W9.

On the other hand, if it is determined in step W5 that the control conditions in the integrated mode are not satisfied, NO,
The processing of steps W10 to W15 is performed.
This corresponds to the processing of steps W6 to W9 described above. That is, in step W10, it is determined whether or not the control condition in the independent mode is satisfied, and when it is determined YES in step W10, the control condition in the independent mode is satisfied. It is determined whether or not the operation state of the switch S13 is the selection of the "independent mode". In step W11, the operation state of the manual switch S13 is "independent mode".
If YES is selected, the step W1
In 3, the driving assistance by the motors ML and MR in the independent mode is executed.

In step W11, the operation state of the manual switch S13 is not "independent mode" selection NO
If it is determined that it is a bad road in step W12, if it is determined NO in this step W12 is not a bad road, it is determined in step W14 whether it is turning. When it is judged NO in this step W14 which is not during turning, drive assist by the motors ML, MR in the integrated mode is executed in step W15. Further, when it is determined NO in step W10 that the control conditions in the independent mode are not satisfied, when it is determined YES in step W12 that is a bad road, and when it is determined YES in step W14 when it is turning. Respectively prohibit the drive assistance by the motors ML and MR in step W2.

[Description of Independent Mode Positive Drive Control (See FIGS. 10 and 11)] FIGS. 10 and 11 show the details of the positive drive control in the independent mode. The normal drive control in the integrated mode is substantially the same as the normal drive control in the independent mode, except that the same target vehicle speed is applied to the left and right rear wheels.

First, in step Z1, the ground vehicle speed V
After inputting signals such as A and the wheel speed VB, in step Z2, the target vehicle speed VTR is set using the accelerator opening and the gear position of the transmission 4 as parameters.

Then, in step Z3, it is determined whether or not the value obtained by subtracting the actual wheel speed VBL of the left rear wheel 1RL from the target vehicle speed VTR is equal to or higher than the predetermined speed V1. When the determination in step Z3 is NO, it is determined that the drive assist by the positive drive is not necessary, and the normal drive of the left rear wheel is stopped in step Z13. Steps Z3 and Z above
The processing of 14 is also performed independently for the right rear wheel 1RR and 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 in step Z3 is YES, it is determined in step Z4 whether or not the accelerator is fully closed. Even when the determination in step Z4 is YES, the drive assist using the motors ML and MR is not performed. Assuming that the state is not necessary, the process proceeds to step Z14 (in this case, the right and left rear wheels 1RL, 1RR are simultaneously stopped in the normal drive).

When the determination in step Z4 is NO, in step Z5 the lateral G acting on the vehicle body is calculated based on the vehicle speed VA and the steering angle of the steering wheel. Thereafter, in step Z6, the correction coefficients k1 and k2 based on the lateral G are set.
To set. That is, here, the correction coefficients for respectively correcting the target wheel speeds of the outer turning wheel and the inner turning wheel that cause a rotation difference during turning are obtained. Then, in step Z7 (FIG. 11), it is determined whether or not the vehicle is making a right turn. When the determination in step Z7 is YES, the process proceeds to step Z9, and the target vehicle speed VT determined in step Z2.
By multiplying R by the correction coefficient k1, the target wheel speed VTRL of the left rear wheel 1RL is calculated, and similarly, by multiplying the target vehicle speed VTR by the correction coefficient k2,
The target wheel speed VTRR of the right rear wheel 1RR is calculated.

When the determination in step Z7 is NO, the target wheel speeds of the left and right rear wheels 1RL and 1RR are calculated in step Z8. After all, the processing of steps Z6 to Z9 corresponds to the processing of increasing the target wheel speed on the turning outer wheel side and decreasing the target wheel speed on the turning inner wheel side. However,
When going straight, the determination in step Z7 becomes NO and the process shifts to step Z8. Since both correction coefficients k1 and k2 are set to 1 (horizontal G is 0 or almost 0) at this time, the left and right rear wheels are The target wheel speeds of 1RL and 1RR are made equal to each other.

After step Z8 or step Z9, at step Z10, the target wheel speed VTRL (VTR
R) to the rear wheel 1RL (1RR) actual wheel speed VBL
Depending on the value obtained by subtracting (VBR), the motor ML (M
The amount Q of oil supplied to R) is determined. The oil amount Q is independently determined for the left and right motors ML and MR. Then, in step Z11, the switching valves VVB · L and VVB are set so that the determined oil amount Q is realized.
・ R is controlled independently.

At the subsequent step Z12, it is determined whether or not the value obtained by subtracting the actual wheel speed VBL of the left rear wheel 1RL from the vehicle speed VA is smaller than a predetermined speed "-V2". After all, the determination in step Z12 is to determine whether or not the actual wheel speed VBL of the left rear wheel 1RL is too large as compared with the vehicle speed VA. Correction is performed to reduce the supply flow rate Q so that the wheel maintains a predetermined slip value.
The processes of steps Z12 and Z13 are similarly performed for the right rear wheel 1RR. When the determination in step Z12 is NO, the process returns without passing through step Z13.

In the positive drive control in the integrated mode, the processing of steps Z5 to Z9 becomes unnecessary, and the target vehicle speed VTR determined in step Z2 becomes the target wheel speeds VTRL, VTRR of the left and right rear wheels 1RL, 1RR. Also, step Z
The switching valve VVA is used to realize the flow rate Q at 11.

[Description of Independent Mode Reverse Drive Control (See FIGS. 12 and 13)] FIGS. 12 and 13 show details of the reverse drive in the independent mode. In addition, reverse drive control in integrated mode,
The switching valve used for flow rate adjustment is only different from the switching valve used in the independent mode, and other aspects are the same as the positive drive control in the independent mode.

First, after inputting various signals in step Z21, the reverse drive flag is set to 1 in step Z22.
Or not. When the determination in step Z22 is NO, in step Z35, it is confirmed where the current state is in the region set with the steering wheel steering angle and the vehicle speed VA as parameters. After this, step Z
In 36, it is determined whether or not the current state is in the hatched area C in the area shown in step Z35. If the determination in step Z36 is YES, step Z
After setting the reverse drive flag to 1 in 37, the process returns to step Z21, while when the determination in step Z36 is NO, the process returns to step Z21 without passing through step Z37.

When step Z37 is passed, step Z2
The determination of 2 is YES, and in this case, step Z23
At, it is determined whether or not ABS control is currently being performed. When the determination in step Z23 is NO, step Z2
In 4, it is determined whether or not the brake depression amount is large. When the determination in step Z24 is NO, it is determined in step Z25 whether the vehicle speed VA is at a low vehicle speed equal to or lower than the predetermined value V3.

When the determination in step Z25 is NO, it is determined in step Z26 whether the accelerator pedal return speed X is equal to or greater than the reference value X0, and this determination is X ≧.
If YES in X0, the foot brake is turned on based on the output signal from the sensor S10 in step Z27.
Determine if it is in a state. When the determination is "foot brake OFF", NO, the gain K is set to K = 1 in step Z28, and "foot brake ON" is YES.
In this case, after the gain K is set to K = 1.5 in step Z29, the process proceeds to step Z30, in which the supply flow rate QA to the motors ML and MR is calculated from the map using the vehicle speed VA and the gear position of the transmission 4 as parameters. Read.
The above map shows that the lower the gear position of the transmission 4, the more the supply flow rate Q.
It is set such that A is large and the supply flow rate QA increases in accordance with the increase of the vehicle speed VA at each gear. Thereafter, in step Z31, the supply flow rate QA is multiplied by the gain K to determine the final supply flow rate Q. Then, in step Z32, the switching valve VV is set so that the flow rate Q determined in step Z31 is supplied to the left and right motors ML and MR.
Controls B / L and VVB / R. After this step Z32, the processes of steps Z33 and Z34 are performed, but this process corresponds to the processes of steps Z12 and Z13 of FIG.

If the determination in any of the steps Z23, Z24, Z25 is YES, or if the determination in step Z26 is NO, the reverse drive control is stopped in step Z38, and then the reverse drive flag is set to 0 in step Z39. Reset to.

The reverse drive control in the integrated mode is performed as a switching valve that realizes the flow rate Q determined in step Z31.
VVA is used.

[Description of Traction Control Control (See FIGS. 14 and 15)] FIGS. 14 and 15 are performed when the determination in step E24 of FIG. 5 is YES, and the traction control is executed by the control unit U3. The drive assist (the left and right independent positive drive) is controlled by using the motors ML and MR during the operation.

First, after inputting various signals in step Z41, in step Z42, the control unit U
Front wheels 1FL, 1 caused by traction control of No. 3
The reduction amount of the torque applied to FR, that is, the reduction amount TF of the generated torque in the engine 2 is read based on the signal from the control unit U3. Then, in step Z43, the vehicle speed reduction amount VC corresponding to the torque reduction amount TF is determined.

In step Z44, the supply flow rate Q to be supplied to the motors ML and MR is determined according to the vehicle speed decrease 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. Then, in step Z45, it is determined whether the traction control has been stopped. Step Z
When the determination at 45 is NO, the lateral G acting on the vehicle body is calculated based on the vehicle speed VA and the steering angle at step Z46. After this, in step Z47, this lateral G
The correction coefficients F1 and F2 based on the above are set. That is, here, a correction coefficient for determining the distribution ratio of the supply flow rates to the motors ML and MR corresponding to the outer turning wheel and the inner turning wheel that cause a rotation difference during turning, that is, a correction coefficient for determining the torque distribution ratio is obtained. . Then, in step Z48 (FIG. 15), it is determined whether the vehicle is turning right. This step Z4
When the determination result in 8 is YES, in step Z49,
The supply flow rate QTRL of the hydraulic oil to the motor ML for driving the left rear wheel 1RL is calculated by multiplying the supply flow rate Q determined in step Z44 by the correction coefficient F1.
Similarly, the supply flow rate QTRR of the hydraulic oil to the motor MR for driving the right rear wheel 1RR is calculated by multiplying the supply flow rate Q determined in step Z44 by the correction coefficient F2.

When the determination in step Z48 is NO, it is determined in step Z50 whether the vehicle is turning left. If the determination in step Z50 is YES,
At step Z51, the supply flow rate QTRL of the hydraulic oil to the motor ML for driving the left rear wheel 1RL is calculated by multiplying the supply flow rate Q determined at step Z44 by the correction coefficient F2. The supply flow rate QTRR of the hydraulic oil to the motor MR for driving the right rear wheel 1RR is calculated by multiplying the supply flow rate Q determined in Z44 by the correction coefficient F1.

Further, when the determination in step Z50 is NO, the vehicle is in a straight traveling state, and therefore the process proceeds to step Z52, and the supply flow rate Q determined in step Z44 is multiplied by 0.5, so that the motors ML and MR are supplied. The hydraulic fluid supply flow rate QTR (L, R) of is calculated.

After all, the processing of steps Z47 to Z52 corresponds to the processing of increasing the driving force on the outer wheel turning side and decreasing the driving force on the inner wheel turning side.

After such processing, in step Z53, the switching valves VVB.L and VVB.R are individually controlled so as to realize the determined oil amount QTR (L, R). In step Z54, it is determined whether 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 "-V4". After all, the determination in step Z54 is to determine 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 in step Z54 is YES, step Z55. At, correction is performed to reduce the supply flow rate Q so that the rear wheels maintain the predetermined slip value.
The processes of steps Z54 and Z55 are similarly performed for the right rear wheel 1RR. When the determination in step Z54 is NO, the process returns without passing through step Z55.

[Explanation of vehicle stop mode control (see FIG. 16)]
FIG. 16 shows the control contents of the vehicle stop mode in step D9 of FIG. First, after inputting various signals in step Z61, it is determined in step Z62 whether or not the accelerator is depressed. When the determination in step Z62 is NO, the target vehicle speed VTR is set to 0 in step Z63, and then step Z
At 64, feedback control is performed on the supply flow rates to the motors ML and MR 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 (left and right independent control).

By the way, when the transmission 4 is an automatic transmission (in this case, the clutch 3 is a torque converter), even if the accelerator is not stepped on, traveling at a very low speed is called creep. Is to be done. In order to obtain this creep, if the target vehicle speed VTR is set to, for example, 5 km / h, the creep speed can always be kept constant regardless of the slope of the road surface while the vehicle is stopped. Then, the target vehicle speed VTR can be manually selected, for example, in the range of 0 to 15 km / h in a continuously variable or stepless manner (the target vehicle speed is 0).
When there is no creep).

In this embodiment, the above steps E34, E
The deceleration detection unit 100 configured to detect the rapid deceleration state of the vehicle is constituted by 43.

Further, in steps Z26, Z27 and Z30, the operating state of the vehicle is detected based on the gear position of the transmission 4, the foot brake pedal depression state (foot brake ON state) or the accelerator pedal return speed X. The operating state detection means 101 is configured.

Further, steps E35, E44, Z2
9, when the deceleration detecting means 100 detects a rapid deceleration state of the vehicle, the second driving means 99 causes the motors ML, MR to apply a braking load to the rear wheels 1RL, 1RR by the reverse driving mode. And the braking load on the rear wheels 1RL, 1RR by the motors ML, MR is made variable in accordance with the vehicle operating state detected by the operating state detecting means 101, and the lower the shift stage of the transmission 4, the more When the foot brake pedal is depressed, and further when the accelerator pedal return speed X is equal to or greater than the reference value X0, the control means 102 is configured to increase the braking load on the rear wheels 1RL and 1RR, respectively.
Is configured.

Therefore, in the above embodiment, the hydraulic pressure as the driving energy for the motors ML and MR is stored in the accumulator 41 when the vehicle is decelerated. When the vehicle suddenly decelerates, the motor M is driven by the hydraulic pressure PO stored in the accumulator 41 during the sudden deceleration.
L and MR are reversely driven, and by this reverse driving, the rear wheels 1RL and 1RR are braked independently of the braking force of the engine 2.
In this way, the first drive means 98 that connects the engine 2 to the front wheels 1FL and 1FR is independent of the second drive means 9 separately.
9 is operated, and the rear wheels 1RL,
Since a braking load is applied to 1RR, this motor ML,
By making the braking load characteristic by MR variable, compared with the case where the engine braking effect by the engine 2 alone is obtained,
Various engine braking effects can be obtained, and the vehicle braking distance can be shortened by increasing the braking load, for example. Moreover, when the vehicle is decelerated, the motor ML,
Since the engine braking effect by MR is added, the burden on the occupant can be reduced and the drivability of the vehicle can be improved.

At this time, the gear shift stage of the transmission 4, the foot brake pedal depression state, and the accelerator pedal return speed are detected as the vehicle operating states, and the braking load on the rear wheels 1RL, 1RR is detected in accordance with these vehicle operating states. Is variable. Specifically, when the foot brake pedal is depressed, or the accelerator pedal return speed X is the reference value X.
When it is 0 or more, the control gain K is K = 1.5 in all cases.
Is set to a large value and the supply flow rate Q to the motors ML and MR is set.
Is increased, and when the shift stage of the transmission 4 is low, the supply flow rate Q is increased based on the map characteristics. As the supply flow rate Q increases, the braking load on the rear wheels 1RL, 1RR increases. In this way, the braking load of the rear wheels 1RL, 1RR by the motors ML, MR changes according to the driving state of the vehicle, so that the engine braking characteristic of the entire vehicle including the braking load by the motors ML, MR and the braking load by the engine 2 is added. Therefore, it is possible to obtain an appropriate braking characteristic according to the driving state of the vehicle.

That is, it is considered that there is a demand for greater deceleration as the gear position of the transmission 4 becomes lower, and the rear wheels 1RL, 1
Since the braking load on the RR increases, an appropriate engine braking characteristic according to the gear stage of the transmission 4 can be obtained. Further, when the foot brake pedal is depressed, a large braking force is required, and the rear wheels 1RL,
Since the braking load for 1RR is increased, an appropriate engine braking characteristic corresponding to a large braking force can be obtained. Further, even when the accelerator pedal return speed X is higher than the reference value X0, a large braking force is required. Therefore, the braking load on the rear wheels 1RL, 1RR is also increased at this time, and the large braking force is commensurate with the large braking force. Appropriate engine braking characteristics can be obtained.

In the above embodiment, the motors ML and MR are driven in reverse by the reverse drive mode to obtain the engine brake. However, in addition to this, the variable orifice VVC is used.
A hydraulic lock mode using the throttle resistance of L, VVC / R and a pressure accumulation mode in which the accumulator 41 accumulates pressure with the motors ML and MR as pumps are used, and the braking load at that time can be changed according to the operating state of the vehicle. Alternatively, the same operation and effect as those of the above embodiment can be obtained.

Further, the present invention is not limited to the above embodiment, but includes the following modified examples.

(1) The mode (integrated mode or independent mode) selected by the manual switch and the mode (integrated mode or independent mode) in which the control conditions are satisfied in step D12 of FIG. 4 (see FIGS. 5 to 8). If the mode is different, the driving assistance using the motors ML and MR may not be performed at all.

(2) In the case of a bad road, the drive assistance using the motors ML and MR may be performed in the same manner as in the case of a good road.

(3) Prioritizing the mode selection by the manual switch, the control areas of the integrated mode and the independent mode may be set according to the rough road.

Further, it is also possible to allow only the control in the independent mode on the bad road, while allowing the control in the integrated mode on the slow road. On the contrary, only the control in the integrated mode may be permitted on the bad road, while the control in the independent mode may be permitted on the slow road.

(4) The left and right rear wheels 1RL, 1RR are driven by the engine 2, and the left and right front wheels 1FL, 1FR are driven by the motor M.
It may be driven by L and MR. Further, the actuators may be changed from the hydraulic motors ML and MR to electric motors. In that case, the energy storage means is a battery or a capacitor that stores electric power as driving energy for the electric motor. In addition, the motors ML and M are constantly operated during traveling.
It is also possible to drive using R.

(5) When traveling straight, the independent mode may be used at low speed, and the integrated mode may be used at high speed. Such a setting can be performed on a high μ road, but particularly on a low μ road, it is preferable in terms of satisfying the improvement of running performance at low speed and the straight running stability at high speed. .

(6) The invention is not limited to the manual transmission 4 and can be applied to a vehicle equipped with an automatic transmission.

[0126]

As described above, according to the invention of claim 1, first driving means for driving either one of the left and right front wheels or the left and right rear wheels by the engine through the transmission,
A second one in which the other wheel is driven by an actuator such as a motor
For the vehicle provided with the drive means, the actuator controls the second drive means so as to apply the braking load to the wheels at the time of deceleration. Therefore, when the engine braking effect by only the engine of the first drive means is obtained. In comparison, for example, by increasing the braking load, it is possible to shorten the idling distance until the brake pedal is depressed, which in turn shortens the vehicle braking distance, reduces the burden on the occupants, and improves the drivability of the vehicle. It is possible to improve.

According to the invention of claim 2, the driving state of the vehicle is detected, and the braking load on the wheels by the actuator is made variable according to the driving state of the vehicle.
It is possible to properly set the entire engine braking characteristic to which the braking load by the actuator is applied according to the driving state of the vehicle.

According to the invention of claim 3, the gear shift stage of the transmission is detected as the operating state of the vehicle, and the lower the gear shift stage of the transmission is, the more the braking load on the wheels by the actuator is increased. It is possible to obtain an appropriate engine braking characteristic according to the gear stage of the machine.

According to the invention of claim 4, it is detected that the foot brake pedal is depressed, and when the foot brake pedal is depressed, the braking load on the wheels by the actuator is increased. Therefore, a large braking force is required. Appropriate engine braking characteristics can be obtained when the foot brake pedal is depressed.

According to the invention of claim 5, the return speed of the accelerator pedal is detected, and the braking load on the wheel by the actuator is increased when the return speed of the accelerator pedal is high, so that the return speed of the accelerator pedal is high. Therefore, when a large braking force is required, it is possible to obtain an appropriate engine braking characteristic corresponding to the required braking force.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of the present invention.

FIG. 2 is an explanatory diagram showing a hydraulic system of a vehicle according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a control system.

FIG. 4 is a main flowchart showing a motor drive control routine.

FIG. 5 is a flowchart showing a part of a mode determination control routine.

FIG. 6 is a flowchart showing the rest of the mode determination control routine.

FIG. 7 is a flowchart showing another part of the mode determination control routine.

FIG. 8 is a flowchart showing still another part of the mode determination control routine.

FIG. 9 is a flowchart showing an execution determination control routine.

FIG. 10 is a flowchart showing a part of an independent positive drive control routine.

FIG. 11 is a flowchart showing the remaining part of the independent positive drive control routine.

FIG. 12 is a flowchart showing a part of an independent reverse drive control routine.

FIG. 13 is a flowchart showing the remaining part of the independent reverse drive control routine.

FIG. 14 is a flowchart showing a part of a traction control routine.

FIG. 15 is a flowchart showing the remaining part of the traction control routine.

FIG. 16 is a flowchart showing a control routine of a vehicle stop mode.

[Explanation of symbols]

 1FL, 1FR Front wheels 1RL, 1RR Rear wheels 2 Engine 4 Transmission 41 Accumulator 98 First drive means 99 Second drive means 100 Deceleration detection means 101 Operating state detection means 102 Control means P Pump ML, MR Motor (actuator) U1 Main control Unit S6 Gear position sensor S9 Accelerator opening sensor S10 Foot brake depression sensor

Claims (5)

[Claims] 1. A drive system for a vehicle comprising: first drive means for driving one of the left and right front wheels or left and right rear wheels by an engine; and second drive means for driving the other wheel by an actuator. Deceleration detecting means for detecting a deceleration state of the vehicle; and control means for controlling the second driving means so that the actuator applies a braking load to the wheels when the deceleration state of the vehicle is detected by the deceleration detecting means. A drive device for a vehicle, wherein the drive device is provided. 2. The vehicle drive device according to claim 1, further comprising a driving state detecting means for detecting a driving state of the vehicle, wherein the control means detects a braking load applied to a wheel by an actuator by the driving state detecting means. A drive device for a vehicle, which is configured to be variable according to a driving state of the vehicle. 3. The drive system for a vehicle according to claim 2, wherein the operating state detecting means detects the gear stage of the transmission as the operating state of the vehicle, and the control means has a low gear stage of the transmission. A drive device for a vehicle, which is configured to increase a braking load applied to a wheel by an actuator. 4. The vehicle drive device according to claim 2, wherein the driving state detecting means detects that the foot brake pedal is stepped on as the driving state of the vehicle, and the control means includes a foot brake pedal. A vehicle drive device configured to increase a braking load applied to a wheel by an actuator when the vehicle is stepped on. 5. The vehicle drive device according to claim 2, wherein the driving state detecting means detects a return speed of the accelerator pedal as a driving state of the vehicle, and the control means has a predetermined returning speed of the accelerator pedal. A drive device for a vehicle configured to increase a braking load on a wheel by an actuator when the value is equal to or more than a value.