JP4241848B2 - Vehicle driving force control device - Google Patents

Description

  The present invention relates to a vehicle driving force control apparatus in which a clutch is interposed between a motor and wheels.

Conventionally, as a driving force control device for a vehicle in which a front wheel is driven by an engine and a rear wheel can be driven by an electric motor, and a clutch or a speed reducer is interposed in a torque transmission path from the motor to the rear wheel, for example, a patent Some are described in Document 1.
This device drives a motor as a start assist, and a dog clutch connected as a clutch is exemplified as the clutch. If it is determined that the dog clutch is locked in the engaged state even if the clutch is controlled to be turned off, the motor is temporarily driven in the direction of canceling the torque acting on the dog clutch or in both the forward and reverse directions. Thus, it is disclosed that the clutch is unlocked when the clutch control is off.
JP 11-091389 A

If the clutch remains locked despite the clutch control state being turned off, the motor will over-rotate due to the wheel speed increasing due to traveling conditions such as traveling on a steep downhill. There is a risk of reaching the area. Such a situation is likely to occur particularly when a reduction gear having a large reduction ratio is interposed.
Therefore, if the vehicle speed increases after the clutch control state is turned off and the rotation of the motor approaches the over-rotation region and then the clutch is to be released, the motor may be in an over-rotation state.
The present invention has been made paying attention to the above points, and it is possible to avoid a clutch engagement lock state after the clutch control is turned off by controlling the driving state of the vehicle according to the clutch state. A driving force control device is provided.

In order to solve the above-described problems, the present invention provides a main drive source that drives main drive wheels, a motor that drives sub-drive wheels that are controlled to have a target motor torque, and a power transmission path from the motor to the wheels. A driving force control device for a vehicle, comprising: a clutch interposed between the main driving source output adjusting means and a main driving source output adjusting means capable of adjusting the output of the main driving source regardless of a driver's acceleration instruction;
The clutch includes a first rotating member that is connected to the rotating shaft on the motor side, a second rotating member that is connected to the rotating shaft on the wheel side, and an engagement formed between the first and second rotating members. An engagement member inserted in the joint space, a retainer that regulates the circumferential position of the engagement member, and the engagement of the clutch by fixing and releasing the retainer with respect to one of the first and second rotating members. A clutch operating unit that controls disengagement, and the phase between the other of the first and second rotating members and the cage changes when the cage is fixed by the clutch operating unit. A mechanism that allows the coupling to be engaged between the first and second rotating members so that torque can be transmitted between the first and second rotating members, and during the fixed state of the cage by the clutch operating portion, the target Motor torque is not enough to drive the driven wheel If it determined to be, and is characterized in further comprising a clutch state control means for reducing the output of the main drive source via the main drive source output adjusting means.
Here, “activate during the fixed state of the cage by the clutch operating portion” means that the cage operates continuously during the fixed state of the cage and when the cage is fixed. It means to include both cases of temporary operation.

According to the present invention, by adopting a clutch having the above-described mechanical connection / disconnection mechanism as a clutch interposed between the motor and the wheel, an inexpensive clutch can be provided and the clutch control is turned off ( Even when the torque transmission torque is large during the transition from fixing to release of the cage), it is possible to reduce the occurrence of shock at the time of actual clutch disengagement.
Further, even if the clutch having the above mechanism is employed, in the present invention, when the state of the clutch operation unit is changed from the fixed state (clutch connection control state) to the released state (clutch disengagement control state), the clutch Can be kept from being locked in the connected state.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a system configuration of a vehicle according to the present embodiment.
As shown in FIG. 1, in the vehicle of this embodiment, left and right front wheels 1L and 1R are main drive wheels driven by an engine 2 (main drive source) that is an internal combustion engine, and left and right rear wheels 3L and 3R are A driven wheel that can be driven by a motor 4 (motor).

That is, the output torque Te of the engine 2 is transmitted to the left and right front wheels 1L, 1R through the transmission 30 and the difference gear 31.
The transmission 30 is provided with shift position detecting means 32 for detecting the current shift range, and the shift position detecting means 32 outputs the detected shift position signal to the 4WD controller 8.

  A main throttle valve 15 and a sub-throttle valve 16 are interposed in the intake pipe line 14 (for example, an intake manifold) of the engine 2. The throttle opening of the main throttle valve 15 is adjusted and controlled in accordance with the amount of depression of an accelerator pedal 17 that is an accelerator opening instruction device (acceleration instruction operation unit). The main throttle valve 15 is mechanically linked to the depression amount of the accelerator pedal 17, or the engine controller 18 is electrically operated according to the depression amount detection value of the accelerator sensor 40 that detects the depression amount of the accelerator pedal 17. By performing adjustment control, the throttle opening is adjusted. The detected depression amount value of the accelerator sensor 40 is also output to the 4WD controller 8.

  The sub-throttle valve 16 is adjusted and controlled by a rotation angle corresponding to the number of steps using the step motor 19 as an actuator. The rotation angle of the step motor 19 is adjusted and controlled by a drive signal from the motor controller 10220. The sub-throttle valve 16 is provided with a throttle sensor, and the number of steps of the step motor 19 is feedback-controlled based on the detected throttle opening value detected by the throttle sensor. Here, by adjusting the throttle opening of the sub-throttle valve 16 to be less than or equal to the opening of the main throttle valve 15, the output torque of the engine 2 is controlled independently of the driver's operation of the accelerator pedal. Can do.

Further, an engine speed detection sensor 21 that detects the speed of the engine 2 is provided, and the engine speed detection sensor 21 outputs the detected signal to the engine controller 18 and the 4WD controller 8.
Reference numeral 34 denotes a brake pedal that constitutes a braking instruction operation unit, and a stroke amount of the brake pedal 34 is detected by a brake stroke sensor 35. The brake stroke sensor 35 outputs the detected brake stroke amount to the braking controller 10236 and the 4WD controller 8.

The braking controller 10236 controls the braking force acting on the vehicle through the braking devices 37FL, 37FR, 37RL, 37RR such as disc brakes equipped on the wheels 1L, 2R, 3L, 3R according to the input brake stroke amount. .
Further, a part of the rotational torque Te of the engine 2 is transmitted to the generator 7 through the endless belt 6, so that the generator 7 is obtained by multiplying the rotational speed Ne of the engine 2 by the pulley ratio. Rotate at Nh.

  As shown in FIG. 2, the generator 7 includes a voltage regulator 22 (regulator) for adjusting the output voltage V, and the generator control command value c <b> 1 (duty ratio) is controlled by the 4WD controller 8. Thus, the power generation load torque Th and the generated voltage V for the engine 2 are controlled through the field current Ifh. That is, the voltage regulator 22 receives the generator control command c1 (duty ratio) from the 4WD controller 8, adjusts the field current Ifh of the generator 7 to a value corresponding to the generator control command c1, and generates power. It can be output to the 4WD controller 8 while detecting the output voltage V of the machine 7. The rotational speed Nh of the generator 7 can be calculated from the rotational speed Ne of the engine 2 based on the pulley ratio.

The electric power generated by the generator 7 can be supplied to the motor 4 via the electric wire 9. A junction box 10 is provided in the middle of the electric wire 9. The drive shaft of the motor 4 can be connected to the rear wheels 3L and 3R via the speed reducer 11 and the clutch 12. Reference numeral 13 represents a differential.
In addition, a current sensor 23 is provided in the junction box 10, and the current sensor 23 detects the current value Ia of the electric power supplied from the generator 7 to the motor 4, and outputs the detected armature current signal to 4WD. Output to the controller 8. In addition, a voltage value (voltage of the motor 4) flowing through the electric wire 9 is detected by the 4WD controller 8. Reference numeral 24 denotes a relay, and the cutoff and connection of the voltage (current) supplied to the motor 4 is controlled by a command from the 4WD controller 8.

In addition, the field current Ifm of the motor 4 is controlled by a command from the 4WD controller 8, and the drive torque is adjusted to the target motor torque by adjusting the field current Ifm. Reference numeral 25 denotes a thermistor that measures the temperature of the motor 4.
A motor rotation speed sensor 26 that detects the rotation speed Nm of the drive shaft of the motor 4 is provided, and the motor rotation speed sensor 26 outputs the detected rotation speed signal of the motor 4 to the 4WD controller 8.

Further, the clutch 12 of the present embodiment is a clutch that is connected and disconnected by a mechanical mechanism as described below, and the electromagnetic clutch unit 106 is connected or disconnected according to a clutch control command from the 4WD controller 8. In this state, connection / disconnection control of the clutch 12 is performed.
Next, the mechanism and configuration of the clutch 12 will be described with reference to FIGS.

  The inner ring member 100 that is the second rotating member and the outer ring member 101 that is the first rotating member are disposed coaxially, and are related to the space between the outer diameter surface of the inner ring member 100 and the inner diameter surface of the outer ring member 101. A plurality of rollers 102, which are a combination, are inserted. The inner ring surface of the outer ring member 101 is a cylindrical surface. On the outer diameter surface of the inner ring member 100, cam surfaces 100a are formed at predetermined intervals along the circumferential direction. The cam surface 100a is, for example, a flat surface, so that an engagement space 103 is formed between the cam surface 100a and the inner diameter surface of the outer ring member 101 opposed in the radial direction. The wedge space 103a becomes narrower as it goes to both sides. If the engagement space 103 is formed with a wedge space 103a (a space where the facing distance between the inner ring member 100 and the outer ring member 102 is smaller than that of the roller 102) on both sides in the circumferential direction, the cam surface 100a has a concave shape or the like. Other contour-shaped surfaces may be used. Further, the adjacent cam surfaces 100a do not need to be continuous, and may be formed so as to be opened at a predetermined interval. The rollers 102 are disposed in the engagement spaces 103, and the plurality of rollers 102 are accommodated in the pockets of the cage 104 interposed between the inner ring member 100 and the outer ring member 101. Has been. That is, the distance between the rollers 102 is regulated by the cage 104, that is, the circumferential position is regulated. The cage 104 is connected to the inner ring member 100 via a switch spring 105. The switch spring 105 can exert a spring force in the circumferential direction with respect to the cage 104, and the position of each roller 102 accommodated in the pocket of the cage 104 corresponds to the corresponding engagement space 103. The retainer 104 is imparted and supported toward a neutral position arranged at a substantially central position.

  Further, the clutch 12 is provided with an electromagnetic clutch portion 106 that constitutes a clutch operation portion, and when the energization is turned on (clutch control current on), the cage 104 is connected to the outer ring member 101 (the outer ring member 102). The retainer 104 is fixed to the outer ring member 104), and the energization is turned off (clutch control current off), whereby the retainer 104 and the outer ring member 101 are disconnected (the retainer 104 is released from the outer ring member 104). . Reference numeral 107 denotes an armature, reference numeral 108 denotes a rotor, and reference numeral 109 denotes an electromagnetic coil.

The outer ring member 101 is connected to the drive shaft side of the motor 4, and the inner ring member 100 is connected to the rotating shaft on the wheel side.
In the clutch 12 of the above mechanism, when the retainer 104 is in the released state, the roller 102 is held at the center position of the engagement space 103 by the action of the switch spring 105, so that the inner ring member 100 and the outer ring member 101 No torque is transmitted via the roller 102 between the inner ring member 100 and the outer ring member 101 so that the inner ring member 100 and the outer ring member 101 can rotate independently.

  On the other hand, when the cage 104 is fixed, if a phase difference occurs between the inner ring member 104 and the cage 104 due to a relative rotational difference between the inner ring member 100 and the outer ring member 101, the elasticity of the switch spring 105 is increased. The roller 102 moves to the wedge space 103a against the force and engages with the wedge space 103a, that is, the roller 102 engages between the inner ring member 100 and the outer ring member 101, so that the inner ring member 100 and the outer ring member 101 are engaged. Torque can be transmitted between the two. The torque transmission direction differs depending on which of the left and right wedge spaces 103a the roller 102 is engaged with.

That is, in the clutch 12 having the above-described configuration, connection / disconnection of the clutch 12 is controlled by turning on / off the energization of the electromagnetic clutch unit 106 (on / off of the clutch control current).
Each wheel 1L, 1R, 3L, 3R is provided with a wheel speed sensor 27FL, 27FR, 27RL, 27RR. Each wheel speed sensor 27FL, 27FR, 27RL, 27RR outputs a pulse signal corresponding to the rotation speed of the corresponding wheel 1L, 1R, 3L, 3R to the 4WD controller 8 as a wheel speed detection value.

As shown in FIG. 5, the 4WD controller 8 includes a generator controller 8A, a relay controller 8B, a motor controller 8C, a clutch controller 8D, a surplus torque calculator 8E, a target torque limiter 8F, and a surplus torque converter 8G. The motor torque adjustment unit 8J and the clutch release processing unit 8H are provided.
The generator control unit 8A adjusts the field current Ifh by outputting the generator command value c1 of the generator 7 while monitoring the generated voltage V of the generator 7 through the voltage regulator 22.

The relay control unit 8 </ b> B controls interruption / connection of power supply from the generator 7 to the motor 4.
The motor control unit 8C adjusts the field current Ifm of the motor 4 to adjust the torque of the motor 4 to a required value.
The clutch control unit 8D controls the state of the clutch 12 by turning on / off the energization of the electromagnetic clutch unit 106 of the clutch 12 and keeps the electromagnetic clutch unit 106 energized while it is determined to be in the four-wheel drive state. .

In addition, processing is performed in a cycle of surplus torque calculating unit 8E → target torque limiting unit 8F → surplus torque converting unit 8G at predetermined sampling times in accordance with each input signal.
Next, the surplus torque calculation unit 8E performs processing as shown in FIG.
That is, first, in step S10, the rear wheels 3L, 3R (secondary driving wheels) are calculated from the wheel speeds of the front wheels 1L, 1R (main driving wheels) calculated based on the signals from the wheel speed sensors 27FL, 27FR, 27RL, 27RR. By subtracting the wheel speed, the slip speed ΔVF that is the acceleration slip amount of the front wheels 1L, 1R is obtained, and the process proceeds to step S20.

Here, the calculation of the slip speed ΔVF is performed as follows, for example.
An average front wheel speed VWf that is an average value of the left and right wheel speeds of the front wheels 1L and 1R and an average rear wheel speed VWr that is an average value of the left and right wheel speeds of the rear wheels 3L and 3R are calculated by the following equations, respectively.
VWf = (VWfl + VWfr) / 2
VWr = (VWrl + VWrr) / 2
Next, from the deviation between the average front wheel speed VWf and the average rear wheel speed VWr, the slip speed (acceleration slip amount) ΔVF of the front wheels 1L and 1R which are the main drive wheels is calculated by the following equation.
ΔVF = VWf -VWr

In step S20, it is determined whether or not the determined slip speed ΔVF is greater than a predetermined value, for example, zero. When it is determined that the slip speed ΔVF is 0 or less, it is estimated that the front wheels 1L and 1R are not accelerated and slipped, so the process proceeds to step S30, and after zero is substituted for Th, the process returns.
On the other hand, if it is determined in step S20 that the slip speed ΔVF is greater than 0, it is estimated that the front wheels 1L and 1R are slipping at acceleration, and therefore the process proceeds to step S40.

In step S40, the absorption torque TΔVF necessary for suppressing the acceleration slip of the front wheels 1L, 1R is calculated by the following equation, and the process proceeds to step S50. The absorption torque TΔVF is an amount proportional to the acceleration slip amount.
TΔVF = K1 × ΔVF
Here, K1 is a gain obtained through experiments or the like.
In step S50, the current load torque TG of the generator 7 is calculated based on the following equation, and then the process proceeds to step S60.
V x Ia
TG = K2 ・ ─────────
K3 x Nh
here,
V: Voltage of the generator 7
Ia: Armature current of the generator 7
Nh: Number of rotations of the generator 7
K3: Efficiency
K2: coefficient
It is.
In step S60, the surplus torque, that is, the target power generation load torque Th to be loaded by the generator 7 is obtained based on the following formula, and the process returns.
Th = TG + TΔVF

Next, the processing of the target torque limiting unit 8F will be described based on FIG.
That is, first, in step S110, it is determined whether or not the target power generation load torque Th is larger than the maximum load capacity HQ of the generator 7. When the target power generation load torque Th is determined to be equal to or less than the maximum load capacity HQ of the generator 7, the power generation load torque Th is restored. On the other hand, when it is determined that the target power generation load torque Th is larger than the maximum load capacity HQ of the generator 7, the process proceeds to step S120.

In step S120, an excess torque ΔTb exceeding the maximum load capacity HQ at the target power generation load torque Th is obtained by the following equation, and the process proceeds to step S130.
ΔTb = Th−HQ
In step S130, the current engine torque Te is calculated based on signals from the engine speed detection sensor 21 and the throttle sensor, and the process proceeds to step S140.

In step S140, an engine torque upper limit value TeM obtained by subtracting the excess torque ΔTb from the engine torque Te is calculated as shown in the following equation, and the calculated engine torque upper limit value TeM is output to the engine controller 18, and then the process proceeds to step S150. Transition.
TeM = Te−ΔTb
In step S150, after the maximum load capacity HQ is substituted for the target power generation load torque Th, the process returns.

Next, the process of the surplus torque converter 8G will be described based on FIG.
First, in step S200, it is determined whether Th is greater than zero. If it is determined that Th> 0, the front wheels 1L and 1R are accelerated and slipped, and the process proceeds to step S210. Further, if it is determined that Th ≦ 0, the front wheels 1L and 1R are in a state in which they do not undergo acceleration slip, so that the two-wheel drive state is entered and step S270 is entered.

  In step S210, it is determined whether or not it is a transition from the four-wheel drive state to the two-wheel drive state. If it is determined that the transition is to the two-wheel drive, the process proceeds to step S270. Therefore, in step S290, the clutch connection processing unit 8K is executed, that is, the electromagnetic clutch unit 106 is energized through the clutch control unit 8D, and the process proceeds to step S220.

For example, when it is determined that the motor rotational speed has approached the allowable limit rotational speed, or when it is determined that the target motor torque is decreasing and the target motor torque is equal to or less than a predetermined threshold torque T-TM1 (for example, 1 [Nm]). Then, it is determined that the clutch 12 is to be shifted to the two-wheel drive state where the clutch 12 should be released.
Here, whether or not the target motor torque that is a torque command value to the motor 4 is decreasing is determined by simply comparing the target motor torque with the previous value as follows, for example.
Tm (n-1) -Tm (n-2) <0

Here, the subscript (n-1) indicates the target motor torque before one calculation cycle, and the subscript (n-2) indicates the target motor torque before two calculation cycles. However, in order to suppress the influence of noise or the like, it may be determined whether or not the motor motor is decreasing based on the history value of the target motor torque for three cycles or more as follows (in the following formula, the value for six cycles is Example used). Further, when the target motor torque value is continuously decreased for a plurality of calculation periods, it may be determined that the target motor torque value is decreasing.
{Tm (n-1) + Tm (n-2) + Tm (n-3)}
-{Tm (n-4) + Tm (n-5) + Tm (n-6)} <0
Next, in step S220, the rotational speed Nm of the motor 4 detected by the motor rotational speed sensor 21 is input, a target motor field current Ifm corresponding to the rotational speed Nm of the motor 4 is calculated, and the target motor field After the magnetic current Ifm is output to the motor control unit 8C, the process proceeds to step S230.

  Here, the target motor field current Ifm with respect to the rotational speed Nm of the motor 4 is a constant predetermined current value when the rotational speed Nm is equal to or lower than the predetermined rotational speed, and when the motor 4 exceeds the predetermined rotational speed. First, the field current Ifm of the motor 4 is reduced by a known field weakening control method. That is, when the motor 4 is rotated at a high speed, the motor torque decreases due to the increase of the motor induced voltage E. Therefore, as described above, when the rotational speed Nm of the motor 4 exceeds a predetermined value, the field current Ifm of the motor 4 is By reducing the induced voltage E and reducing the induced voltage E, the current flowing through the motor 4 is increased to obtain the required motor torque. As a result, even if the motor 4 rotates at high speed, the increase in the motor induced voltage E is suppressed and the decrease in the motor torque is suppressed, so that the required motor torque can be obtained. In addition, by controlling the motor field current Ifm in two stages of less than a predetermined rotation speed and more than a predetermined rotation speed, the control electronic circuit can be made cheaper than continuous field current control.

  Note that motor torque correction means for continuously correcting the motor torque by adjusting the field current Ifm according to the rotational speed Nm of the motor 4 with respect to the required motor torque may be provided. That is, for the two-stage switching, the field current Ifm of the motor 4 is preferably adjusted according to the motor rotation speed Nm. As a result, even if the motor 4 rotates at high speed, the increase in the induced voltage E of the motor 4 is suppressed and the decrease in the motor torque is suppressed, so that the required motor torque can be obtained. In addition, since smooth motor torque characteristics can be achieved, the vehicle can be driven more stably than in the two-stage control, and the motor drive efficiency can always be improved.

Next, in step S230, the corresponding target motor torque Tm (n) is calculated from a map or the like based on the power generation load torque Th calculated by the surplus torque calculation unit 8E, and the process proceeds to step S240.
In step S240, after the process of the motor torque adjustment unit 8J is performed, the process proceeds to step S250.
In step S250, using the target motor torque Tm (n) and the target motor field current Ifm as variables, the corresponding target armature current Ia is obtained based on a map or the like, and the process proceeds to step S260. In step S260, based on the target armature current Ia, the duty ratio c1, which is a generator control command value, is calculated and output, and then the process returns.

On the other hand, when it is determined that the clutch is to be disengaged or the vehicle is in the two-wheel drive state and the process proceeds to step S270, the clutch disengagement processing unit 8H is executed, and then the process proceeds to step S280.
Here, in the clutch release processing unit 8H of the present embodiment, the electromagnetic clutch unit 106 is turned off through the clutch control unit 8D to release the cage 104.
In step S280, after setting "0" to the duty ratio c1 which is a generator control command value, it returns. Also, other processing is performed when shifting from the four-wheel drive state to the two-wheel drive state.

Next, the process of the motor torque adjustment unit 8J will be described with reference to FIG. The motor torque adjustment unit 8J constitutes clutch state control means.
First, in step S310, the wheel speeds of the rear wheels 3R and 3L are input from the wheel speed sensors of the rear wheels, and the wheel acceleration A of the rear wheels 3R and 3L is calculated by performing differential calculation on the wheel speeds. The process proceeds to S320.

In step S320, the minimum motor torque TA that can drive the rear wheels 3R and 3L by the motor 4 based on the wheel acceleration A of the rear wheel based on the following equation, that is, the minimum motor torque TA on the motor side for driving the wheel. And the process proceeds to step S330. In this embodiment, the motor torque TA has a margin of margin allowance α (> 0), but α = 0 may be used.
TA = (IM × A / R) + α
Here, IM: Inertia between motor 4 and clutch 12
R: Rear wheel tire diameter
It is.

In step S330, the current target motor torque Tm (n) is compared with the motor torque. If the current target motor torque is greater or equal, the process returns without doing anything. On the other hand, if the target motor torque Tm (n) is smaller, the process proceeds to step S340.
The process of S330 is a process of determining whether or not the acceleration of the motor-side rotation axis is greater than or equal to the acceleration of the wheel-side rotation axis at the clutch position.
In step S340, the motor torque TA is substituted for the target motor torque Tm (n), and the process ends.

Next, processing of the engine controller 18 will be described.
In the engine controller 18, processing as shown in FIG. 10 is performed based on each input signal for every predetermined sampling time.
That is, first, in step S610, the target output torque TeN requested by the driver is calculated based on the detection signal from the accelerator sensor 40, and the process proceeds to step S620.
In step S620, it is determined whether there is an input of the limited output torque TeM from the 4WD controller 8. If it is determined that there is an input, the process proceeds to step S630. On the other hand, if it is determined that there is no input, the process proceeds to step S670.

In step S630, it is determined whether the limited output torque TeM is smaller than the target output torque TeN. If it is determined that the limit output torque TeM is smaller, the process proceeds to step S640. On the other hand, if the limited output torque TeM is larger or equal to the target output torque TeN, the process proceeds to step S670.
In step S640, the target output torque TeN is limited by substituting the limited output torque TeM for the target output torque TeN, and the process proceeds to step S670.

In step S670, the current output torque Te is calculated based on the throttle opening, the engine speed, etc., and the process proceeds to step S680.
In step S680, a deviation ΔTe ′ of the target output torque TeN with respect to the current output torque Te is output based on the following equation, and the process proceeds to step S690.
ΔTe ′ = TeN−Te
In step S690, a change Δθ of the throttle opening θ corresponding to the deviation ΔTe is calculated, and an opening signal corresponding to the change Δθ of the opening is output to the step motor 19 to return.
Here, S620 to S640 constitute main drive source output adjusting means.

Next, the operation of the apparatus having the above configuration will be described.
When the road surface μ is small or the torque transmitted from the engine 2 to the front wheels 1L, 1R becomes larger than the road surface reaction force limit torque due to a large amount of depression of the accelerator pedal 17 by the driver, that is, the main driving wheels 1L, When the front wheels 1L and 1R, which are 1R, are accelerated and slipped, the electromagnetic clutch unit 106 is energized to connect the clutch 12, and the generator 7 generates power with a power generation load torque Th corresponding to the acceleration slip amount. Thus, the four-wheel drive state is entered. Subsequently, the driving torque transmitted to the front wheels 1L, 1R is adjusted so as to approach the road surface reaction force limit torque of the front wheels 1L, 1R, thereby shifting to the two-wheel driving state. As a result, the acceleration slip at the front wheels 1L and 1R which are the main drive wheels is suppressed.

In addition, the motor 4 is driven by surplus power generated by the generator 7 and the rear wheels 3L and 3R which are driven wheels are also driven, thereby improving the acceleration of the vehicle.
At this time, since the motor 4 is driven with a surplus torque exceeding the road surface reaction force limit torque of the main drive wheels 1L, 1R, energy efficiency is improved and fuel efficiency is improved.
Here, when the rear wheels 3L and 3R are always in the driving state, energy conversion corresponding to the conversion efficiency occurs in order to perform several energy conversions such as mechanical energy → electric energy → mechanical energy. As a result, the acceleration performance of the vehicle is reduced as compared with the case of driving with only the front wheels 1L, 1R. For this reason, it is desirable to suppress the driving of the rear wheels 3L and 3R in principle. On the other hand, in the present embodiment, on the slippery road surface or the like, it is effective for the front wheels 1L and 1R in view of the fact that not all of the output torque Te of the engine 2 is transmitted to the front wheels 1L and 1R as a driving force. The unusable driving force is output to the rear wheels 3L and 3R to improve acceleration.

  Further, as described above, when the acceleration slip occurs and the clutch 12 is connected and the vehicle is in the four-wheel drive state, the motor torque continuously decreases as the acceleration slip is suppressed. When it is determined to shift from the four-wheel drive state to the two-wheel drive state, the electromagnetic clutch unit 106 is disconnected and the clutch control is turned off.

  Here, the operation of the clutch 12 employed in the present embodiment will be described. When the electromagnetic clutch portion 106 is energized, the circumferential position of each roller 102 is restrained (fixed) to the outer ring via the cage 104. It will be in the state. When the driving torque from the motor is transmitted to the outer ring member 101 in this state, a phase difference is generated between the outer ring member 101 and the roller 102 and the inner ring member 100, and is relatively positioned at the center portion of the engagement space 103. As shown in FIG. 11, each roller 102 that has been engaged with the left wedge space 103 a can transmit torque from the outer ring member 101 to the inner ring member 100 via the roller 102, and as a result, The rear wheels 3L and 3R, which are driven wheels, are driven by the torque of the motor 4.

  Further, when the energization of the electromagnetic clutch unit 106 is stopped in the torque transmission state from the motor 4, that is, when the cage 104 is released with the clutch control current turned off, the torque transmission torque from the motor 4 gradually decreases. When the spring force of the switch spring 105 is won, the roller 102 returns to the center position of the engagement space 103, and the clutch 12 is actually turned off.

  Therefore, when the clutch 12 having the above-described mechanism is employed, even if the clutch 12 is controlled to be turned off with the motor torque being large (the energization of the electromagnetic clutch unit 106 is stopped), the actual disconnection of the clutch 12 is small in the motor torque. As a result of being always executed in the state (when the motor-side acceleration and the wheel-side acceleration at the clutch position approach the same value), it is possible to suppress a shock that occurs when the actual clutch 12 is disengaged. 12 off control becomes easy. The clutch 12 is inexpensive.

  On the other hand, when the electromagnetic clutch unit 106 is energized, that is, when traveling with a clutch control on, assuming a traveling state such as traveling on a steep downhill, the wheel speeds of the rear wheels 3L and 3R increase. When the acceleration of the inner ring member 100 becomes larger than that of the outer ring member 101, that is, when the torque from the wheel side exceeds the torque from the motor side, the outer ring member 101 and the roller 102 are between the inner ring member 100. As a result of the elimination of the phase difference and the occurrence of a phase difference in the opposite direction, the roller 102 is disengaged, and subsequently, as shown in FIG. 12, the roller 102 with respect to the right wedge space 103a located on the opposite side. Bite. That is, a so-called reverse biting state is established, and a torque transmission state from the rear wheel side toward the motor side is established. In this state, when the energization of the electromagnetic clutch unit 106 is stopped and the cage 104 is released, the reverse biting state is not achieved unless the torque of the motor 4 is increased (or the torque from the wheels does not decrease). Without elimination, the torque from the rear wheels 3L, 3R is transmitted to the motor, the motor 4 is rotated around the rear wheels 3L, 3R, and the motor 4 may over-rotate.

  On the other hand, in the present embodiment, when the electromagnetic clutch unit 106 is energized, that is, when the clutch control is on, the torque of the motor 4 is controlled so that the motor-side acceleration of the clutch 12 is always larger than the wheel-side acceleration. As a result, when the clutch control is turned off (the energization to the electromagnetic clutch unit 106 is stopped), the reverse biting state as described above is not established. Therefore, the clutch 12 can be reliably turned off as the motor torque decreases (or the torque increases from the wheel side).

  For this reason, for example, because the motor speed has approached the over-rotation range due to a steep downhill run, etc., clutch control is kept off (energization of the electromagnetic clutch unit 106 is stopped) from the viewpoint of motor protection. If the device 104 is released, the rotational speed of the motor decreases or the rotation of the rear wheel increases from that point, so that the roller 102 returns to the neutral position and the clutch is disengaged. It is possible to avoid an over-rotation state. At this time, if it is in the reverse engagement state, the reverse engagement is not eliminated and the motor 4 is rotated by the high speed rotation of the rear wheels 3L and 3R, and the rotation speed of the motor 4 is excessive. There is a risk of becoming a state.

  Here, in the above-described embodiment, the case where the motor 4 is driven with the voltage generated by the generator 7 to perform the four-wheel drive is described, but the present invention is not limited to this. You may employ | adopt for a drive system provided with the battery which can supply electric power to the motor 4. FIG. In this case, power may be supplied from the battery, and power supply from the generator 7 may be performed concurrently with the supply from the battery.

Or although the internal combustion engine was illustrated as a main drive source in the said embodiment, you may comprise a main drive source from a motor etc. In the above embodiment, a four-wheeled vehicle is described as an example. However, the present invention may be applied to a two-wheeled vehicle using a motor as a drive source.
In the above system, the case of shifting to the four-wheel drive state according to the acceleration slip of the front wheels has been described. However, the present invention can also be applied to a system that shifts to the four-wheel drive state according to the start time or the accelerator opening degree. It is. That is, the motor driving conditions are not limited to the above conditions.

  Further, in the description of the clutch 12, the engagement space 103 is formed in a portion where the inner ring member 100 and the outer ring member 101 are opposed to each other in the radial direction. 103 may be formed. Further, the cam surface 100a may be provided on the outer ring member 101 side, and the inner ring member 100 and the cage 104 may be fixed and released by the clutch operating portion. Further, a clutch mechanism other than the electromagnetic clutch may be employed as the clutch operation unit.

Next, a second embodiment will be described with reference to the drawings. The same devices as those in the first embodiment will be described with the same reference numerals.
The basic configuration of this embodiment is the same as that of the first embodiment, but the clutch state control means is different. That is, the process of the motor torque adjustment unit 8J and the process of a part of the engine controller 18 are different from those of the first embodiment.
The motor torque adjustment unit 8J according to the second embodiment has a process as shown in FIG. That is, first, in step S310, the wheel speeds of the rear wheels 3L and 3R are input by inputting the wheel speeds of the rear wheels 3L and 3R from the wheel speed sensors of the rear wheels 3L and 3R, and the wheel acceleration A of the rear wheels 3L and 3R is calculated. And the process proceeds to step S320.

In step S320, the motor torque TA corresponding to the wheel acceleration A, that is, the minimum motor torque TA on the motor side for driving the wheel is calculated, and the process proceeds to step S330.
In step S330, the current target motor torque Tm (n) is compared with the motor torque TA. If the current target motor torque is greater or equal, the process proceeds to step S380 and the limit torque TeK is set to “0”. It returns after assigning. On the other hand, if the target motor torque Tm (n) is smaller, the process proceeds to step S350.

The process of S330 is a process of determining whether or not the acceleration of the motor-side rotation shaft at the clutch position is greater than or equal to the acceleration of the wheel-side rotation shaft.
In step S350, a deviation torque ΔTb (= TA−Tm (n)) between the motor torque TA and the target motor torque is calculated, and subsequently in step S360, signals from the engine speed detection sensor 21 and the throttle sensor, etc. Based on the above, the current engine torque Te is calculated, and the process proceeds to step S370.

In step S370, as shown in the following equation, the limit torque TeK obtained by subtracting the torque corresponding to the deviation torque component ΔTb is calculated and output, and then the process ends.
TeK = Te−K5 · ΔTb
K5 is a gain obtained from an experiment or the like.
Here, the motor torque adjustment unit 8J converts the acceleration A of the rear wheels 3L and 3R, which are driven wheels, into the motor torque TA, and calculates the limit torque TeK based on the torque difference in the motor torque. However, the present invention is not limited to this, the target motor torque Tm may be converted into the acceleration of the rear wheel to obtain the difference from the actual acceleration of the rear wheel, and the limit torque TeK may be calculated from the difference of the acceleration.

Next, processing of the engine controller 18 in the present embodiment will be described with reference to FIG. The basic processing flow is the same as in the first embodiment. However, the point that the process of step S612-step S616 is added between step S610 and step S620 differs.
That is, after calculating the target output torque TeN requested by the driver in step S610, the process proceeds to step S612 to determine whether TeK is greater than zero, that is, whether there is an input of the limit torque TeK. If it is determined that TeK is input, the process proceeds to step S614. On the other hand, when it is determined that the limit torque TeK is not input, the process proceeds to step S620 as in the first embodiment.

In step S614, the limit torque TeK and the target output torque TeN are compared. If the limit torque TeK is smaller, the process proceeds to step S616, and if not, the process proceeds to step S620.
In step S616, the target output torque is reduced by substituting the limit torque TeK for the target output torque TeN, and then the process proceeds to step S620.
The processes after step S620 are the same as those in the first embodiment.

  In the present embodiment, the processing of the clutch release processing unit 8H is slightly different. That is, in the clutch release processing unit 8H of the present embodiment, it is determined whether or not the acceleration of the motor-side rotation shaft is equal to or higher than the acceleration of the wheel-side rotation shaft at the clutch position, and the acceleration of the motor-side rotation shaft is the wheel-side rotation. If the acceleration is equal to or greater than the acceleration of the shaft, the energization of the clutch operating unit is stopped as it is, and the clutch is disengaged. On the other hand, if it is determined that the acceleration of the motor-side rotation axis is less than the acceleration of the wheel-side rotation axis, the limit torque TeK is temporarily set to a small value (for example, a value close to zero) temporarily (for example, only for a time of 500 ms). Then, the energization of the clutch operation unit is stopped. Note that this temporary control (for example, only for a time of 500 ms) may be performed unconditionally only once at the time of transition from the four-wheel drive state to the two-wheel drive state when the limit torque TeK is a small value. .

Other configurations are the same as those in the first embodiment.
According to the present invention, while the clutch control is on, that is, while the clutch 12 is controlled to be in the connected state, the upper limit of the engine torque is set so that the acceleration of the motor-side rotating shaft is equal to or higher than the acceleration of the wheel-side rotating shaft. Since the value is controlled, it is possible to prevent or reduce the reverse engagement state of the clutch 12 when the clutch control is turned off, thereby preventing an over-rotation state of the motor.

  Even if the clutch 12 is in the reverse engagement state when the clutch control is actually turned off, the reverse of the clutch 12 can be obtained by temporarily removing the engine torque without further increasing the rotation of the motor. The clutch control can be turned off as the state where the biting state is eliminated. That is, since the motor has approached the allowable limit rotation, when the clutch control is turned off, it is not necessary to increase the rotation speed of the motor in order to eliminate reverse biting.

In the above description, while the clutch control is on, both the control for setting the upper limit value of the engine to the limit torque TeK and the control for temporarily removing the engine torque when the clutch control is turned off are performed. Although used together, only one of the controls may be employed. Further, the control for temporarily removing the engine torque when the clutch control is turned off may be applied to the first embodiment.
Further, control for setting the upper limit value of the engine to the limit torque TeK may be employed in the first embodiment.
Other operations and effects are the same as those in the first embodiment.

It is a schematic device block diagram concerning the embodiment based on the present invention. It is a system configuration figure concerning an embodiment based on the present invention. It is sectional drawing which shows the structure of the clutch which concerns on this embodiment. It is a schematic diagram which shows the mechanism of the clutch which concerns on this embodiment. It is a block diagram which shows the 4WD controller 102 which concerns on embodiment based on this invention. It is a figure which shows the process of the surplus torque calculating part which concerns on embodiment based on this invention. It is a figure which shows the process of the target torque control part which concerns on embodiment based on this invention. It is a figure which shows the process of the surplus torque conversion part which concerns on embodiment based on this invention. It is a figure explaining the motor torque adjustment part which concerns on embodiment of this invention. It is a figure which shows the process of the engine controller which concerns on embodiment based on this invention. It is a figure which shows the state which has torque transmission from a motor to a wheel. It is a figure which shows the state which has torque transmission from a wheel to a motor. It is a figure explaining the motor torque adjustment part which concerns on 2nd Embodiment of this invention. It is a figure which shows the process of the engine controller which concerns on 2nd Embodiment based on this invention.

Explanation of symbols

1L, 1R Front wheel 2 Engine 3L, 3R Rear wheel 4 Motor 6 Belt 7 Generator 8 4WD controller 8A Generator controller 8B Relay controller 8C Motor controller 8D Clutch controller 8E Surplus torque calculator 8F Target torque limiter 8G Surplus Torque converter 8H Clutch release processor 8J Motor torque adjuster 9 Electric wire 10 Junction box 11 Reducer 12 Clutch 14 Intake line 15 Main throttle valve 16 Sub throttle valve 18 Engine controller 19 Step motor 20 Motor controller 21 Engine speed sensor 22 Voltage regulator 23 Current sensor 26 Motor rotation speed sensor 27FL, 27FR, 27RL, 27RR
Wheel speed sensor 30 Transmission 31 Differential gear 32 Shift position detecting means 34 Brake pedal 35 Brake stroke sensor 36 Brake controller 102
37FL, 37FR, 37RL, 37RR
Braking device 40 Accelerator sensor 100 Inner ring member 101 Outer ring member 102 Roller (engagement element)
103 engagement space 103a wedge space 104 cage 105 switch spring 106 electromagnetic clutch portion Ifh generator field current V generator voltage Nh generator speed Ia target armature current Ifm target motor field current E induction of motor Voltage Nm Motor rotation speed (rotation speed)
Th Target generator load torque Tm (n) Current target torque of the motor Te Output torque of the engine

Claims (5)

A main drive source that drives the main drive wheels, a motor that drives the driven wheels under control of the target motor torque, a clutch that is interposed in the power transmission path from the motor to the wheels, and acceleration of the driver In a vehicle driving force control device comprising: a main driving source output adjusting means capable of adjusting the output of the main driving source regardless of an instruction;
The clutch includes a first rotating member that is connected to the rotating shaft on the motor side, a second rotating member that is connected to the rotating shaft on the wheel side, and an engagement formed between the first and second rotating members. An engagement member inserted in the joint space, a retainer that regulates the circumferential position of the engagement member, and the engagement of the clutch by fixing and releasing the retainer with respect to one of the first and second rotating members. A clutch operating unit that controls disengagement, and the phase between the other of the first and second rotating members and the cage changes when the cage is fixed by the clutch operating unit. A mechanism that allows the transmission to be transmitted between the first and second rotating members by biting between the first and second rotating members,
If it is determined that the target motor torque is less than the torque that can drive the driven wheels while the retainer is fixed by the clutch operation unit, the output of the main drive source is reduced via the main drive source output adjusting means. A driving force control device for a vehicle, comprising: a clutch state control means for performing the operation.   The clutch state control means is a torque that allows the target motor torque to drive the driven wheels when the clutch state is changed from the connected state to the disconnected state when the clutch state is changed from the connected state to the disconnected state. 2. The vehicle driving force control apparatus according to claim 1, wherein when it is determined that the power is less than the output, the output of the main driving source is reduced via the main driving source output adjusting means.   The process of reducing the output of the main drive source via the output adjusting means is performed when the clutch state by the clutch operation unit is changed from the connected state to the disconnected state, and when the clutch state is the connected state, the target 3. The vehicle driving force control device according to claim 2, wherein the motor driving force control device is implemented only when it is determined that the motor torque is less than a torque capable of driving the driven wheels.   The motor protection means which cancels | releases the connection of the clutch by the said clutch operation part, when the rotation speed of a motor approaches the permissible limit rotation speed set to the said motor is provided. The vehicle driving force control apparatus according to any one of the preceding claims.   5. A vehicle according to claim 1, wherein a generator driven by an output of a main drive source is provided, and the output of the generator can be supplied to the motor. Driving force control device.

Images