JPH06183278A - Vehicle driving apparatus - Google Patents

Abstract

PURPOSE:To regulate any arbitrary movement of a vehicle being stopped by utilizing a motor for driving an auxiliary driving wheel. CONSTITUTION:Rear wheels 1RL, 1RR serving as auxiliary driving wheels are driven by motors ML, MR. Under the condition of stopping a vehicle, the motors ML, MR are controlled in their driving to provided predetermined desired vehicle speed, for example, desired vehicle speed of zero. A creep phenomenon may be obtained by setting the desired vehicle speed to a value other than zero, for example 10km/h.

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]

When the vehicle is stopped, the driver generally wants the vehicle speed to be maintained at zero. However, there are many situations in which the vehicle is inadvertently moved while the vehicle is stopped depending on the inclination of the road surface. Therefore, the driver depresses the brake pedal when the vehicle is stopped, for example, waiting for a signal. They are forced to do so, and purposely operate the parking brake.

Therefore, it is an object of the present invention to provide a vehicle drive device capable of restricting an arbitrary movement of the vehicle when the vehicle is stopped.

[0007]

In order to achieve the above object, the first constitution of the present invention is as follows. That is, one of the left and right front wheels and the left and right rear wheels is
In a vehicle in which the main driving wheels are driven by the engine via the transmission and the differential device, and the other wheels are auxiliary driving wheels driven by the motor, it is detected that the vehicle is stopped. A vehicle stop detection means and a motor control means for driving and controlling the motor so as to reach a predetermined target vehicle speed when the vehicle stop state is detected by the vehicle stop detection means.

The second aspect of the present invention is as follows. That is, one of the left and right front wheels and the left and right rear wheels is the main drive wheel driven by the engine via the transmission and the differential device, and the other wheel is driven by the hydraulic motor. In a vehicle having auxiliary driving wheels, a circulation circuit forming means for forming a closed hydraulic circulation circuit including the motor in a state where supply and discharge of the hydraulic pressure to the motor are stopped, A variable orifice provided in the circulation circuit, a vehicle stop detection means for detecting that the vehicle is in a stopped state, and a circulation circuit formed by the circulation circuit forming means when the vehicle stop state is detected by the vehicle stop detection means. In addition to the above-described state, a vehicle stop control means for fully closing the variable orifice is provided.

Further, the present invention has the following third construction. That is, one of the left and right front wheels and the left and right rear wheels is the main drive wheel driven by the engine via the transmission and the differential device, and the other wheel is the auxiliary drive driven by the motor. In a wheeled vehicle, a vehicle stop detection unit that detects that the vehicle is in a stopped state, an inclination detection unit that detects a road surface inclination state in the front-rear direction of the vehicle, and a vehicle stop state is detected by the vehicle stop detection unit. When the motor is operated, the motor is provided with a motor control means for generating a driving force in a direction opposite to the down direction in the inclination directions detected by the inclination detection means.

[0010]

According to the first aspect of the present invention, the first aspect corresponds to the first aspect.
With the configuration as described in, when the vehicle is stopped,
By controlling the drive of the motor, the vehicle can be maintained at a predetermined target vehicle speed, and the driver does not need an operation for coping with a situation in which the actual vehicle speed greatly changes from the target vehicle speed.

By adopting the structure described in claim 2, it is possible to surely obtain the most desired state of zero vehicle speed when the vehicle is stopped.

By adopting the structure as described in claim 3, it is possible to obtain a very low speed running called a so-called creep phenomenon.

According to the fourth aspect of the present invention, the zero vehicle speed can be secured and the clear speed can be set according to the intention of the driver.
It is possible to arbitrarily select one of traveling at a very low speed using the driving phenomenon.

According to the fifth aspect of the present invention, the left and right motors, that is, the left and right auxiliary drive wheels are independently controlled to ensure that the target vehicle speed is achieved regardless of the vehicle state. It will be preferable for securing.

With the structure as set forth in claim 6, the left and right auxiliary drive wheels are integrated with each other to maintain the target vehicle speed in a state in which the stability of the vehicle is sufficiently ensured, and particularly the vehicle speed is set to zero. When it does, it becomes preferable.

By adopting the structure as described in claim 7, not only is it preferable in terms of securing the target vehicle speed, but also
At the time of the next start, it is possible to deal with whether the situation is where stability is important or turning is important.

With the structure as described in claim 8, it is preferable in terms of securing the target vehicle speed when the vehicle is stopped when a predetermined control mode is obtained by connecting the left and right hydraulic motors. Become.

By adopting the structure as claimed in claim 9 corresponding to the second structure of the present invention, the rotation resistance of the motor is extremely increased when the vehicle is stopped, that is, the auxiliary drive wheels are allowed to freely move. This is preferable for keeping the vehicle speed at zero by controlling it by a motor.

A tenth aspect corresponding to the third aspect of the present invention.
With the configuration as described in (1), it is preferable to drive the motor in a direction opposite to the direction in which the vehicle easily moves when the vehicle is stopped to prevent the vehicle from moving freely when the vehicle is stopped. Becomes

[0020]

[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 steered wheels, are linked by a steering link 7 such as a tie rod, and the steering link 7 and the steering wheel 8 are linked by 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 is 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 the opening / closing valve V is connected to 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, as will be described later, there are a total of eight types of control modes, 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.

[0032]

[Table 1]

In each of the control modes shown in Table 1, the operating states of the valves that perform the main functions 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 later, the motor ML is set so 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. 3). The clutch 12 may be either in the engaged state or the disengaged state.

(5) Accumulation mode The accumulation mode is used for the vehicle, that is, the rear wheels 1RL, 1R while traveling.
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). This stop mode will be described later in detail.

(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, and the hydraulic pressure supply / discharge line is cut off. In addition to this, the clutch 12
Is closed, the variable orifices VVC.L and VVC.R are fully closed, and the on-off valve VVD is closed. As a result, the rotational resistances of the motors ML and MR become extremely large, and the rear wheels 1RL and 1RL serving as auxiliary drive wheels.
It is regulated that the RR tries to move freely.

(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 becomes abnormally high, -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 and U2 are control units each configured by using a microcomputer, and 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 (anti-lock brake control). In addition, S1 to S12 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 unit U1. 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 sensor S11 is an ignition switch, and the switch S12 is a parking switch that is turned on when the parking brake is activated.

The signals of the sensors or switches S5 to S12 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. A control signal is output to the adjusting means 81. The wheel speed signals detected by the sensors S1 to S4 are transmitted from the control unit U2 to the control unit U1,
The signals from the sensors S1 to S4 may be directly input to the control unit U1.

Description of Flow Chart (FIGS. 3 to 5) Next, the control contents of the control unit U1 will be described with reference to the flow charts of FIG. E and Z respectively indicate steps. First of all, FIG. 3 shows the start when the ignition switch is turned on.
After the signals from each sensor are read in D1,
At D2, it is determined whether or not it is the time when the ignition switch is turned off. NO in this determination of D2
In this case, at D3, the safety valve VVG is closed as a premise for controlling the motor.

After D3, at D4, it is judged if the vehicle speed is substantially zero. When the determination in D4 is YES, it is determined in D6 whether or not the shift position of the transmission 4 is neutral. If YES in the determination of D6, it is determined in D7 whether or not the parking brake is operated. When the determination in D7 is YES, it is determined that the vehicle is in the parking state, and the contents of the parking mode described above are executed (see Table 1). In addition,
For the detection of the parking state, it is possible to add a condition that the accelerator is not stepped on, as in the case where the vehicle is stopped, which will be described later.

If NO in D7, it is determined in D9 whether or not the accelerator is depressed. When the determination in D9 is NO, it is determined that the vehicle is in the stopped state, and the contents of the stop mode described above are executed (see Table 1). When the result of the determination in D9 is YES, the process is returned as it is.

When the determination in D4 is NO, in D5, each mode to be described later is determined and execution is performed according to the determination result.

If YES in the determination of D2,
At D11, after the above parking mode shown in Table 1, the switching valve VVJ is closed at D12 to the left end position shown in FIG. 1 to hold the clutch 12 in the engaged state. At D13, the safety valve VVG is opened.

Details of the control contents of D5 in FIG. 3 are shown in FIGS. First, in E21 of FIG. 4, after signals from the respective sensors are read, it is determined in E22 whether or not the vehicle is traveling backward. This determination is, for example,
This is performed by checking whether or not the shift position of the transmission 4 is in the backward shift stage or in the state. When the determination in E22 is YES, in E23, positive drive is performed in the independent mode described later.

If the determination in E22 is NO, it is determined in E24 whether or not the vehicle is traveling forward. This determination is made by checking whether or not the shift position of the transmission 4 is in a state in which the forward shift speed is selected. E2
When the result of the determination in No. 4 is NO, the transmission 4 is in the neutral position, and in this case, the transmission is directly returned. When the determination in E24 is YES, the control after E26, which is the control content during forward movement, is appropriately performed.

At E26, it is judged if the vehicle is currently traveling straight. In this embodiment, whether or not the vehicle is going straight is determined by calculating the lateral G based on the steering angle of the steering wheel and the vehicle speed, and when the lateral G is equal to or less than a predetermined value, the vehicle is going straight.

When the determination in E26 is YES, E27 to
The processing of E39 is performed. Finally, the control conditions for performing the forward drive (E28) and the reverse drive (E35), the pressure accumulation mode (E33, E39) or the hydraulic lock mode (E31, E37) in the integrated mode are satisfied. Whether or not it is determined.

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 at E26 in FIG.
5 is performed, but FIG. 5 is premised on the time of 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.

Description of Flow Chart (FIG. 6) FIG. 6 shows the details of the positive drive control in the independent mode. The forward drive control in the integrated mode is substantially the same as the forward drive control in the independent mode, except that the same target vehicle speed is applied to the left and right rear wheels and that the switching valve VVA is controlled. Is done as follows. First, after the data is input in Z1, the target vehicle speed VTR is set in Z2 by using the accelerator opening and the shift position of the transmission 4 as parameters.
Is set.

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 made 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. 7) FIG. 7 shows details of reverse driving in the independent mode. The forward drive control in the integrated mode is the same as the forward drive control in the independent mode except that the switching valve used for adjusting the flow rate is different from the switching valve used in the independent mode. Is done as follows. 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.

Vehicle Stop Mode (FIG. 8) FIG. 8 shows the setting of the target vehicle speed in the vehicle stop mode. That is, when it is determined at D10 in FIG. 3 that the vehicle is in the stop mode, the target vehicle speed is set to zero at Z41, and then the actual vehicle speed becomes the target vehicle speed at Z42 by the independent mode. Thus, the drive of the motor is controlled (there is a forward drive and a reverse drive depending on the direction in which the vehicle tries to move freely).

Modified Example 1 of Vehicle Stop Mode (FIG. 9) FIG. 9 shows a modified example of the vehicle stop mode. In this example, a target vehicle speed setting switch S13 is manually operated by the driver. (See Figure 2). The target vehicle speed selectable by the manual switch S13 is, for example,
“Zero”, “5 km / h”, “10 km / h].” 15 k
4 types of "m / h" are prepared in advance. Of course,
The target vehicle speed is from "zero" to a predetermined vehicle speed, for example, "15 km /
It is also possible to set so as to select steplessly between "h".

On the premise of the above, in Z45, the target vehicle speed is set according to the operating state of the manual switch S13. Next, at Z46, it is judged if the steering angle of the steering wheel is equal to or larger than a predetermined steering angle. If YES in the determination of Z46, the drive control of the motor is performed in Z47 by the independent mode so that the target vehicle speed is achieved. In addition, if NO in the determination of Z46, the drive control of the motor is performed. At Z48, the drive of the motor is controlled by the integrated mode so that the target vehicle speed is achieved.

Modification 2 of Stop Mode (FIG. 10) FIG. 10 shows another embodiment when the vehicle is stopped. In this example, a sensor S14 (see FIG. 2) that detects the degree of inclination (gradient) of the road surface in the front-rear direction of the vehicle body is used to prevent the vehicle from freely moving due to the inclination. Drive control is performed (the target vehicle speed corresponds to zero).

First, at Z51 in FIG. 10, it is determined whether or not the road surface is a forward descent. Y is determined by the determination of Z51.
In the case of ES, in Z52, the motor driving force required to keep the vehicle stopped is determined based on the degree of inclination, that is, the gradient and the vehicle weight. Then, in Z53, in order to prevent the vehicle from trying to move forward, Z5
The motors ML and MR are driven by the power determined in step 2 so as to move the vehicle rearward. In Z52, the same control as that shown in FIG. 6 can be performed by calculating the target vehicle speed corresponding to the required driving force.

If NO in the determination of Z51, Z5
At 4, it is determined whether or not the road surface is rising forward. If YES in the determination of Z54, Z55, Z5
The process of No. 6 is performed, but this corresponds to the process of Z52 and Z53, and is different only in that the motor drive control is performed in the direction of moving the vehicle forward. N by Z54 discrimination
When it is O, the road surface is flat and it is assumed that there is no possibility that the vehicle will move freely, and the vehicle is returned as it is.

Although the embodiments have been described above, the present invention is not limited to this, and includes, for example, the following cases. (1) In the case of an automatic transmission with a torque converter, set the target vehicle speed to a value other than zero only when it is in the driving range (securing the creep), and when it is in the neutral range, set the target vehicle speed. It may be automatically set to zero. Of course,
Even in the case of an automatic transmission, the target vehicle speed may be set to be manually selected. (2) 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. (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). (4) The motor is not limited to a hydraulic type, but may be an electric type. (5) When the vehicle is stopped, an arbitrary movement of the vehicle may be restricted by increasing the rotation resistance of the motor as a hydraulic lock mode. (6) When setting the target vehicle speed to a value other than zero, that is, when trying to obtain the creep phenomenon, once confirming that the vehicle speed has become zero, the motor drive control for setting the target vehicle speed is performed. It may be started. That is, the creep phenomenon may be obtained after the target vehicle speed is once zero and the vehicle is completely stopped. Note that, without confirming that the actual vehicle speed becomes zero, it is also possible to start the motor drive control for making the target vehicle speed when the actual vehicle speed is lower than the target vehicle speed (accelerator opening zero. Is assumed).

[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.

[Explanation of symbols]

 U1: Control unit (for motor control) U2: Control unit (for ABS control) P: Pump ML, MR: Motor 1FL, 1FR: Front wheel 1RL, 1RR: Rear wheel 2: Engine 4: Transmission 5: Differential device 12: Clutch 71: Communication path 51L, 51R: Communication path (for forming circulation circuit) VVD: Open / close valve (for communication path opening / closing) VVC / L, VVC / R: Variable orifice

Claims (10)

[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. A vehicle having auxiliary driving wheels, the vehicle stop detection means for detecting that the vehicle is in a stopped state, and the motor is set to a predetermined target vehicle speed when the vehicle stop state is detected by the vehicle stop detection means. And a motor control means for controlling the driving so that the driving apparatus for a vehicle. 2. The target vehicle speed according to claim 1, wherein the target vehicle speed is zero. 3. The target vehicle speed according to claim 1, wherein the target vehicle speed is set to a value other than zero. 4. The target vehicle speed according to claim 1, wherein a plurality of target vehicle speeds are set in advance to include zero and a value other than zero, and the motor control means uses one of the plurality of target vehicle speeds by a manual operation.
Two target vehicle speeds are also selected. 5. The motor according to claim 1, wherein a pair of left and right motors are provided to drive the left and right auxiliary drive wheels independently of each other, and the motor control means is provided for each of the left and right motors. Control the data independently. 6. The clutch according to claim 1, further comprising a clutch for mechanically connecting the left and right auxiliary drive wheels, wherein the clutch is engaged in a stopped state in which the motor control means is operated. 7. The motor according to claim 1, wherein a pair of left and right motors are provided to individually drive the left and right auxiliary drive wheels, and the motor control means has a small steering angle. Controls the left and right motors under the same control condition, and controls the left and right motors under independent conditions when the steering angle of the steering wheel is large. 8. The motor according to claim 1, wherein the motor is of a hydraulic type and is composed of a pair of left and right motors for individually driving the left and right auxiliary drive wheels. A communication passage that connects the motors to each other, and an on-off valve that opens and closes the communication passage, and the on-off valve is closed when the motor control means is operated. 9. 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 a hydraulic motor. In a vehicle having auxiliary driving wheels to be driven, a circulation circuit forming means for forming a closed hydraulic circulation circuit including the motor in a state where supply and discharge of the hydraulic pressure to the motor are stopped. A variable orifice provided in the circulation circuit; a stop detection means for detecting that the vehicle is in a stopped state; and a circulation circuit formed by the circulation circuit forming means when the stop state of the vehicle is detected. And a vehicle stop control means for fully closing the variable orifice while forming a circuit. 10. 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 that has auxiliary driving wheels, the vehicle stop detection means for detecting that the vehicle is in a stopped state, the inclination detection means for detecting a road surface inclination state in the longitudinal direction of the vehicle, and the vehicle stop state by the vehicle stop detection means A motor control means for generating a driving force in a direction opposite to the down direction in the tilt direction detected by the tilt detection means when the state is detected. A characteristic vehicle drive device.