JP3272616B2 - Vehicle yaw moment control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yaw moment control device for a vehicle that changes steering characteristics by distributing different torques to left and right wheels.

[0002]

2. Description of the Related Art The left and right wheels of a vehicle are mutually connected by a transmission and a torque transmission clutch, and a driving force is generated on one of the left and right wheels, and a braking force is generated on the other right and left wheels to control the yaw moment. By setting the amount of distribution of the driving force and the braking force as a function of the product of the longitudinal acceleration and the lateral acceleration of the vehicle, an undesirable yaw moment generated when the turning vehicle accelerates or decelerates is canceled. One has already been proposed by the present applicant (see Japanese Patent Application No. 7-247336).

[0003]

As known from the theory of the friction circle of a tire, the grip force acting on the ground contact surface of the tire includes a front-rear driving force (braking force) and a lateral cornering force. And their resultant force does not exceed the static frictional force at the ground contact surface. Therefore, for example, when a front-wheel drive vehicle is turning near the limit of the grip force of the tire, increasing the longitudinal acceleration by applying the driving force to the front wheel, which is the driving wheel, reduces the cornering force of the front wheel accordingly. become. The turning vehicle keeps stability around the yaw axis by the balance between the front wheel cornering force and the rear wheel cornering force. Therefore, the decrease in the front wheel cornering force causes the front portion of the vehicle to swing outwards, There is a problem that the tendency to understeer increases. In particular, when the grip of the tire reaches its limit and the slip ratio increases,
While the driving force decreases gradually, the cornering force sharply decreases, so that the understeer tendency becomes remarkable.

The present invention has been made in view of the above circumstances, and has as its object to accurately compensate for the tendency of an understeer occurring in a front-wheel-drive vehicle during turning.

[0005]

According to the first aspect of the present invention, left and right front wheels as drive wheels and a driven wheel as driven wheels are provided.
Between the left and right rear wheels and between the left and right front wheels and / or between the left and right rear wheels
Torque distribution means for distributing torque and longitudinal acceleration of the vehicle
Longitudinal acceleration calculation means for calculating degree, and calculated longitudinal acceleration
The amount of torque distribution by the torque distribution means
A torque distribution amount determining means for controlling the torque distribution to increase.
And Te yaw moment control device smell of a vehicle, the torque
The distribution amount determining means determines the amount of
The cornering force of the wheels decreases and the vehicle
Understeer tendency is compensated for even understeer tendency.
To compensate, the torque distribution should be a value that is directly proportional to the longitudinal acceleration.
It is characterized in that it is further increased significantly. This feature
According to the above, when the torque is distributed between the left and right wheels of the front wheel drive vehicle in accordance with the increase in the longitudinal acceleration of the vehicle, the torque distribution amount is increased more than a value directly proportional to the longitudinal acceleration. Even if the cornering force of the front wheels decreases with an increase in acceleration, that is, with an increase in the driving force of the front wheels, and even if the vehicle has an unintended understeer tendency, the torque distribution amount that distributes the understeer tendency to the left and right wheels. Can be compensated for by increasing.

According to the second aspect of the present invention, the driving wheels and
Left and right front wheels as driven wheels, left and right rear wheels as driven wheels, and left
The torque is distributed between the right front wheels and / or between the left and right rear wheels.
Torque distribution means and lateral acceleration to calculate the lateral acceleration of the vehicle
Degree calculation means and torque according to the calculated increase in lateral acceleration
Control so that the torque distribution amount by the distribution means increases
Yaw moment of a vehicle equipped with torque distribution amount determining means
In the control device, the torque distribution amount determining means may be a vehicle.
Cornering in which the front wheels are generated according to the increase in lateral acceleration
Understeer tends to be unintended due to lack of force
In order to compensate for the understeer tendency even when
Allocation increased further than the value directly proportional to lateral acceleration
It is characterized by making it. According to this feature, when the torque is distributed between the left and right wheels of the front wheel drive vehicle in accordance with the increase in the lateral acceleration of the vehicle, the torque distribution amount is increased more than a value directly proportional to the lateral acceleration. The cornering force generated by the front wheels in response to the increase in the lateral acceleration of the vehicle is insufficient, and even if the vehicle tends to unintentionally understeer, the amount of torque distribution that distributes the understeering tendency to the left and right wheels is increased. Can compensate.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

FIGS. 1 to 5 show a first embodiment of the present invention. FIG. 1 is an overall configuration diagram of a front engine / front drive vehicle equipped with a torque distribution control device, and FIG. 2 is a circuit of an electronic control unit. FIG. 3 is a block diagram illustrating the configuration, FIG. 3 is a diagram illustrating a yaw moment generated in a turning vehicle, FIG. 4 is a diagram illustrating a yaw moment generated based on engagement of a hydraulic clutch, and FIG. 5 is a corrected longitudinal acceleration Xg. And a corrected lateral acceleration Yg '.

As shown in FIG. 1, a transmission M is connected to the right end of an engine E mounted horizontally on the front part of the vehicle body. The engine E and the transmission M drive left front wheels W _FL and right front wheels. W _FR is driven.

The left and right rear wheels W _RL , W _RR are rotated between the axles 1 _L , 1 _R of the left rear wheel W _RL and the right rear wheel W _RR as driven wheels at mutually different rotational speeds. Transmission 2 to be connected
Is provided. Transmission 2 constitutes a torque distribution unit of the present invention, a first hydraulic clutch 3 _L and the second hydraulic clutch 3 _R is provided, when engaging the first hydraulic clutch 3 _L, left rear wheel The rotational speed of W _RL is reduced and the right rear wheel W
_RR rotation speed of the accelerated and engaging the second hydraulic clutch 3 _R, wheels W _RL rotational speed after the left is increased rotation speed of the right rear wheel W _RR is decelerated.

[0011] That is, the first shaft 4 is transmission 2 disposed on the left and right axles 1 _L, 1 _R and coaxially left and right axles 1 _L, 1 _R
And a second shaft 5 and a third shaft 6 arranged in parallel with each other and coaxially with each other. The first hydraulic clutch 3 _L is arranged between the second shaft 5 and the third shaft 6. Rutotomoni, the second hydraulic clutch 3 _R is disposed between the right axle 1 _R and the first shaft 4. The small-diameter first gear 7 provided on the right axle 1 _R meshes with the large-diameter second gear 8 provided on the second shaft 5,
The small-diameter third gear 9 provided on the third shaft 6 meshes with the large-diameter fourth gear 10 provided on the first shaft 4. The fifth gear 11 provided on the left axle 1 _L meshes with the sixth gear 12 provided on the third shaft 6.

The first gear 7 and the third gear 9 have the same number of teeth, and the second gear 8 and the fourth gear 10 have the same number of teeth. Is set to be larger than the number of teeth. Fifth gear 11
And the number of teeth of the sixth gear 12 are set to be the same as each other.

[0013] Accordingly, when engaging the first hydraulic clutch 3 _L, the right rear wheel W _RR is right axle 1 _R, the first gear 7, the second gear 8, the second shaft 5, the first hydraulic clutch 3 _L, Third axis 6, sixth
Gear 12 is connected to the left rear wheels W _RL via the fifth gear 11 and the left axle 1 _L. At this time, the rotation speed of the left rear wheel _WRL is reduced with respect to the rotation speed of the right rear wheel _WRR according to the gear ratio of the first gear 7 and the second gear 8. That is, the left and right rear wheels W _RL , W
_{When the RR} is rotating at the same speed, the first hydraulic clutch 3
_{When L} is engaged, the rotation speed of the right rear wheel W _RR is increased, and the rotation speed of the left rear wheel W _RL is reduced.

When the second hydraulic clutch 3 _R is engaged, the right rear wheel W _RR is moved to the right axle 1 _R , the second hydraulic clutch 3 _R ,
First shaft 4, fourth gear 10, third gear 9, third shaft 6, sixth
Gear 12 is connected to the left rear wheels W _RL via the fifth gear 11 and the left axle 1 _L. At this time, the rotation speed of the left rear wheel _WRL is increased with respect to the rotation speed of the right rear wheel _WRR according to the gear ratio of the fourth gear 10 and the third gear 9. That is, the left and right rear wheels W _RL ,
When W _RR is to engage the second hydraulic clutch 3 _R from a state rotating at the same speed, the rotational speed of the left rear wheels W _RL is increased rotation speed of the right rear wheel W _RR is decelerated.

The engagement force of the first hydraulic clutch 3 _L and the second hydraulic clutch 3 _R can be controlled steplessly by adjusting the magnitude of the hydraulic pressure applied to them, so that the left and right rear wheels W The rotational speed ratio of _RL and W _RR also
~ It is possible to control steplessly within a range determined by the gear ratio of the fourth gears 7, 8, 9, 10.

[0016] The electronic control unit U, an engine speed sensor S ₁ for detecting the rotational speed of the engine E, the intake pipe absolute pressure sensor S for detecting an intake pipe absolute pressure of the engine E
_2, a steering angle sensor S ₃ for detecting the steering angle of the steering wheel 13, a lateral acceleration sensor S ₄ for detecting a lateral acceleration of the vehicle, wheel speed sensors for detecting in order to calculating the speed of the four wheels rpm respectively The signals from S ₅ are input.

As is apparent from FIG. 2, the electronic control unit U includes a longitudinal acceleration calculating means 20 and a lateral acceleration calculating means 2.
1, torque distribution amount determining means 22 and left / right turning determination means 2
The longitudinal acceleration calculating means 20 includes a gear position determining means 24, a driving wheel torque calculating means 25, a rotational acceleration calculating means 26, a drive system inertia correcting means 27, and a running resistance correcting means 28. The calculating means 21 includes a lateral acceleration estimating means 29, an adding means 30, and an average value calculating means 31. The torque distribution amount determining means 22 includes a corrected longitudinal acceleration calculating means 32, a corrected lateral acceleration calculating means 33, and a control amount calculating means 34. Be composed.

The oil pumped from the oil tank 14 by the oil pump 15 is regulated in pressure by a pressure regulating valve 16 composed of a linear solenoid valve, and is supplied to a first hydraulic clutch 3 _L via a first opening / closing valve 17 _L composed of an ON / OFF valve. And a second on-off valve 17 comprising an ON / OFF valve.
It is supplied to the second hydraulic clutch 3 _R through _R. The electronic control unit U generates a braking force on one of the left and right rear wheels W _RL and W _RR and a driving force on the other by engaging one of the first hydraulic clutch 3 _L and the second hydraulic clutch 3 _R of the transmission 2. For this purpose, the magnitude of the output oil pressure of the pressure regulating valve 16 is controlled, and the opening and closing of the first opening and closing valve _17L and the second opening and closing valve _17R are controlled.

Next, describing calculation of longitudinal <br/> acceleration by the longitudinal acceleration calculating means 20. Gear position determining means 24
Determines a gear position of the transmission M based on the vehicle speed V detected by the engine speed Ne and the wheel speed sensor S ₅ detected by the engine speed sensor S _1. Driven wheel torque calculating means 25, the correction by the gear ratio i of the gear position to calculate the engine torque, the detected it based on the absolute intake pipe detected by the intake pipe absolute pressure sensor S ₂ pressure Pb and the engine rotational speed Ne In addition, the driving wheel torque is calculated. The rotational acceleration detecting means 26 detects the rotational acceleration of the driving system based on the vehicle speed V, and the driving system inertia correcting means 27 corrects the driving wheel torque based on the rotational acceleration of the driving system.
Furthermore the running resistance correction means 28 by adding a correction to the driven wheel torque by the running resistance which is detected based on the vehicle speed V, the finally calculated longitudinal acceleration of the vehicle.

Next, the lateral acceleration by the lateral acceleration calculating means 21 is calculated.
The calculation of the degree will be described. In this specification, the following
In order to simplify the formula as much as possible, the lateral acceleration must be
A number that indicates how many times the size of
Dimensionless lateral acceleration Yg without the option and longitudinal acceleration
A numerical value indicating how many times the gravitational acceleration G is.
Dimensionless longitudinal acceleration Xg with no dimension
Therefore, the lateral acceleration is “Yg × G”
The longitudinal acceleration is represented by “Xg × G”.

[0021] Thus by the lateral acceleration estimation unit 29 the estimated lateral acceleration Yg ₁ map search based on the θ steering angle detected by the steering angle sensor S ₃ and the vehicle speed V. The estimated lateral acceleration Yg ₁ is added by the adding means 30 to the actual lateral acceleration Yg ₂ detected by the lateral acceleration sensor S ₄ , and the average value calculating means 31 multiplies the added value by ，. Acceleration Y
actual lateral acceleration Yg detected by g ₁ and the actual lateral acceleration sensor S ₄
A lateral acceleration Yg × G , which is an average value of ₂ , is calculated. Thus, by correcting the actual lateral acceleration Yg ₂ by the estimated lateral acceleration Yg _1, without time lag accurate lateral acceleration Yg ×
G can be obtained.

Subsequently, the corrected longitudinal acceleration calculating means 32 of the torque distribution amount determining means 22 calculates the dimensionless corrected longitudinal acceleration Xg ' similarly to Xg as a function of the dimensionless longitudinal acceleration Xg by the following equation. Calculated based on

Xg ′ = A × Xg + B × Xg ³ (1) The right side of the equation (1) is the sum of the first-order and third-order terms of Xg, and A and B are positive constants set in advance. is there. what if,
If the right side of equation (1) is only the first-order term (A × Xg),
The dimensionless correction longitudinal acceleration Xg 'is the dimensionless longitudinal acceleration X
g increases in direct proportion to the increase in g. However, due to the presence of the third-order term (B × Xg ³ ) on the right side of equation (1), the dimensionless
The correction-corrected longitudinal acceleration Xg ′ increases more than a value that is directly proportional to the dimensionless longitudinal acceleration Xg.

Similarly, the corrected lateral acceleration calculating means 33 of the torque distribution amount determining means 22 converts the dimension to dimensionless like Yg.
The corrected lateral acceleration Yg ′ is calculated based on the following equation as a function of the dimensionless lateral acceleration Yg.

Yg ′ = C × Yg + D × Yg ³ (2) The right side of the equation (2) is the sum of the primary and tertiary terms of Yg, and C and D are positive constants set in advance. is there. what if,
If the right side of equation (2) is only the first-order term (C × Yg),
Dimensionless correction lateral acceleration Yg 'is made to increase in direct proportion to the increase in dimensionless lateral acceleration Yg, the presence of (2) on the right side of the cubic term (D × Yg ^3), dimensionless of complement <br/> Seiyoko acceleration Yg 'it will increase even greater than the value that is directly proportional to the dimensionless lateral acceleration Yg.

[0026] The control amount calculating means 34, as a function of dimensionless complement <br/> positive longitudinal acceleration Xg 'and the non-dimensional correction lateral acceleration Yg' Xg multiplied by '× Yg', pressure regulating valve 16 controls the amount of That is, the amount of torque distributed between the left and right rear wheels W _RL , W _RR is calculated.

Next, the operation of the embodiment of the present invention having the above configuration will be described.

FIG. 3 shows a state in which a vehicle having a weight W (ie, mass W / G) is turning left at a lateral acceleration Yg × G.
At the center of gravity of the vehicle , its mass (W / G) and lateral acceleration
And acts centrifugal force W × Yg is the product of (Yg × G), the centrifugal force W × Yg is applied between the cornering force CFf and rear wheels and the road surface that acts between the front wheel and the road surface Of the cornering force CFr.

W × Yg = CFf + CFr (3) Assuming that the distance between the center of gravity of the vehicle and the front wheels is a, and the distance between the center of gravity and the rear wheels is b, the cornering force C
The moment M ₁ around the yaw axis due to Ff and CFr is given by M ₁ = a × CFf−b × CFr (4)

When the vehicle is traveling straight, the ground contact load of the left and right wheels is the same, but when the vehicle turns, the contact load changes between the inner turning wheel and the outer turning wheel. That is, since the centrifugal force acting outward in the turning direction acts on the center of gravity of the vehicle body during turning, the vehicle body tends to fall outward in the turning direction. As a result, the turning inner wheel tends to rise from the road surface to reduce the contact load of the turning inner wheel, and the turning inner wheel tends to be pressed against the road surface to increase the contact load of the turning outer wheel.

Further, while the vehicle is traveling at a constant speed, the contact load on the front and rear wheels is constant, but when the vehicle accelerates or decelerates, the contact load on the front and rear wheels changes. In other words, during acceleration, the inertia force acting toward the rear of the vehicle acts on the center of gravity of the vehicle, so that the vehicle tries to tail dive and the ground contact load on the rear wheels increases.
Since the cornering force results rear wheel is increased moment M ₁ in the turning direction opposite the direction acts, also inertial force directed to the front of the vehicle body center of gravity of the vehicle body at the time of deceleration is applied,
Vehicle body vertical load of the front wheel is increased in an attempt to nose dive, resulting front wheel cornering force is a moment M ₁ in the turning direction in the same direction is applied increases (see the solid line arrows and dashed arrows in FIG. 3).

When the vehicle is traveling at a constant speed in a straight line, if the sum of the ground loads of the left and right front wheels is Wf, the ground loads of the front wheels are respectively Wf / 2, but the vehicle turns with a lateral acceleration Yg × G. when it is accelerated and decelerated before and after acceleration Xg × G while the ground load W _FI and ground load W _FO of front turning outer front turning _{inner, W FI = Wf / 2-} Kf × Yg-Kh × Xg ... _{(5) W FO = Wf /} 2 + Kf × Yg-Kh × Xg ... given by (6), also the vertical load W _RI and the turning outer rear wheel of the turning inner to the sum of the vertical load of the left and right rear wheels and Wr The ground contact load W _RO of the rear wheel is given by W _RI = Wr / 2−Kr × Yg + Kh × Xg (7) W _RO = Wr / 2 + Kr × Yg + Kh × Xg (8) In the equations (5) to (8), the coefficient K
f, Kr, and Kh are given by the following equations.

Kf = (Gf ′ × hg ′ × W + hf × Wf) / tf (9) Kr = (Gr ′ × hg ′ × W + hr × Wr) / tr (10) Kh = hg × W / (2 × L) (11) The symbols used here are as follows.

Gf, Gr; front wheel and rear wheel roll stiffness Gf ', Gr'; front wheel, rear wheel roll stiffness distribution Gf '= Gf / (Gf + Gr) Gr' = Gr / (Gf + Gr) hf, hr; front wheel, rear wheel Roll center height hg; center of gravity height hg '; distance from center of gravity to roll axis hg' = hg- (hf × Wf + hr × Wr) / W tf, tr; front wheel, rear wheel tread L; wheel base L = a + b of tire The cornering force determines the ground contact load of the tire.
And the dimensionless lateral acceleration Yg , the cornering force CFf of the front wheel is calculated as follows: the ground contact load W _FI of the front wheel on the inside of the turn given by the equation (5) and the outside load of the corner given by the equation (6). and front wheel ground load W _FO of, by the dimensionless lateral acceleration Yg is given by the following equation.

[0035] _{CFf = W FI × Yg + W} FO × Yg = Wf × Yg-2 × kh × Xg × Yg ... (12) In addition, the cornering force CFr of the rear wheels, the rear wheels of the inside of the turn given by equation (7) And the ground load _WRI of (8)
And ground load W _RO of the rear wheels of the outside of the turn given by the formula, no next
It is given by the following equation based on the normalized lateral acceleration Yg.

[0036] _{CFr = W RI × Yg + W} RO × Yg = Wr × Yg + 2 × kh × Xg × Yg ... (13) (12) and equation (13) is substituted into formula (4) wherein, M ₁ = a × ( Wf × Yg−2 × Kh × Xg × Yg) −b × (Wr × Yg + 2 × Kh × Xg × Yg) = (a × Wf−b × Wr) × Yg−2 × Kh × L × Xg × Yg 14) Here, a × Wf−b × Wr = 0, and (11)
Since Kh = hg × W / (2 × L) from the equation, the above equation (14) gives M ₁ = −hg × W × Xg × Yg (15), and the moment M ₁ around the yaw axis is Acceleration Xg
It can be seen that it is proportional to the product of × G and the lateral acceleration Yg × G. Therefore, (15) if distributed driving force and braking force to the turning inner wheel and turning wheel so as to cancel the moment M ₁ about the yaw axis given by the equation, cornering stability and high speed at the time of acceleration or deceleration during turning Stability can be improved.

On the other hand, as shown in FIG. 4, for example, when a braking force F is generated on the turning inner wheel, if the gear ratio of the transmission 2 is i, a driving force F / i is generated on the turning outer wheel. The moment M ₂ around the yaw axis generated in the vehicle by the braking force F and the driving force F / i is M ₂ = (tr / 2) × F × κ = (tr / 2) × (T / R) × κ (16) Here, κ = 1 + (1 / i), T: clutch torque, R: tire radius.

Therefore, the moment M ₂ is replaced by the moment M ₁
The clutch torque T required to cancel the torque is M ₁ = M
By placing ₂ , T = {2R / (tr × κ)} × hg × W × Xg × Yg (17) As is apparent from the equation (17), the clutch torque T is a value proportional to the product of the longitudinal acceleration Xg and the lateral acceleration Yg. In the above description, the cornering force of the tire is determined by the contact load of the tire and the dimensionless lateral acceleration.
Assuming that the product is a product of Yg , the clutch torque T has a value proportional to the product of the longitudinal acceleration Xg × G and the lateral acceleration Yg × G. , The clutch torque T may be handled as a function of the product of the longitudinal acceleration Xg × G and the lateral acceleration Yg × G.

As shown in Table 1, when the vehicle accelerates during a left turn, the first opening / closing valve _17L is opened according to the judgment of the left / right turn judgment means 23, and the control amount calculation means 34 adjusts. By controlling the output hydraulic pressure of the pressure valve 16 to engage the first hydraulic clutch 3 _L with the clutch torque T given by the equation (17), the rotation speed of the turning inner wheel is reduced, and the braking force F
There thereby occurs by the rotation speed of the outer turning wheel is accelerated driving force F / i to occur, the moment M ₁ in the turning direction opposite to the direction based on the cornering force is to turning performance is improved canceled. Similarly, if engaging the second hydraulic clutch 3 _R in the clutch torque T when the vehicle is accelerated during turning right, the turning performance is canceled moment M ₁ based on the cornering force as before improves.

Further, when the vehicle is decelerated during left turning, when the engaged clutch torque T given the second hydraulic clutch 3 _R in (17), the driving force rotational speed of the inner wheel is accelerated F is generated, the rotational speed of the turning outer wheel is reduced, and a braking force F / i is generated, whereby a moment M in the same direction as the turning direction based on the cornering force is generated.
₁ is canceled out, and high-speed stability performance is improved. Similarly, the first if ask the hydraulic clutch 3 _L engaged by the clutch torque T, Fast stability performance is canceled moment M ₁ based on the cornering force in the same manner as described above when the vehicle is decelerated during turning right Is improved.

[0041]

[Table 1]

Even if the vehicle accelerates or decelerates while traveling straight, the yaw moment of the vehicle does not change, so that the first hydraulic clutch 3 _L and the second hydraulic clutch 3 _R are kept in the disengaged state. .

When the driver further depresses the accelerator pedal to accelerate the vehicle when the front wheels W _FL and W _FR which are the driving wheels are turning near the limit of the grip force of the tire, the reason is as described above. Front wheels W _FL , W
_The cornering force CFf in which _FR occurs may be lower than the actually required cornering force, and the front portion of the vehicle may be swung to the outside of the turn to increase the understeer tendency. At this time, since the clutch torque T given by the equation (17) does not take into account the yaw moment caused by the lack of the cornering force CFf of the front wheels W _FL and W _FR , the occurrence of the above-described understeer tendency is compensated. It is not possible.

[0044] Therefore, instead of the non-dimensional longitudinal acceleration Xg and dimensionless lateral acceleration Yg in (17), the front wheel W
_The dimensionless corrected longitudinal acceleration Xg 'in equation (1) and the dimensionless corrected lateral acceleration Y in equation (2) taking into account the yaw moment due to the lack of the cornering force CFf of _FL and W _FR.
If g ′ is used, that is, if the clutch torque T is calculated by the following equation: T = {2R / (tr × κ)} × hg × W × Xg ′ × Yg ′ (18) Can compensate.

This will be further described with reference to FIG.
The dashed line in (B) is the first line on the right side of Expressions (1) and (2).
Term ( dimensionless longitudinal acceleration Xg and dimensionless lateral acceleration Yg
And the chain line corresponds to the second term on the right side of equation (1) and (2) (the cubic term of dimensionless longitudinal acceleration Xg or dimensionless lateral acceleration Yg), respectively. , And the value of the solid line obtained by adding the value of the chain line corresponds to the dimensionless corrected longitudinal acceleration Xg ′ and the dimensionless corrected lateral acceleration Yg ′. Equation (17), which corresponds to the conventional example, is equivalent to the equation (1) and equation (2) with the tertiary term of the second term on the right-hand side deleted. The corresponding equation (18) can be obtained. According to the present invention,
As the longitudinal acceleration Xg × G or the lateral acceleration Yg × G increases, the clutch torque T increases by an amount corresponding to the tertiary term, and the torque distribution between the left and right front wheels W _FL and W _FR increases accordingly. As a result, the yaw moment generated by the lack of the cornering force CFf of the front wheels W _FL and W _FR can be canceled to prevent the occurrence of the understeer tendency.

FIG. 6 shows a second embodiment of the present invention. In the first embodiment, the dimensionless correction longitudinal acceleration Xg ′ and
The dimensionless correction lateral acceleration Yg ', (1) and equation (2) the longitudinal acceleration dimensionless by formula Xg and dimensionless lateral acceleration Y
g is set as a function, but in the second embodiment, it is dimensionless.
Of correcting longitudinal acceleration Xg 'and the non-dimensional correction lateral acceleration Y
The g ', is set by the table for the dimensionless longitudinal acceleration Xg and dimensionless lateral acceleration Yg as a parameter.
Also in the second embodiment, since the torque distribution amount is increased more than the value directly proportional to the longitudinal acceleration Xg × G or the lateral acceleration Yg × G , the understeering tendency during the turning of the vehicle is compensated for, and the stable turning is achieved. Can be made possible.

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.

For example, although the embodiment has described the torque distribution between the left and right rear wheels W _RL and W _{RR as} driven wheels, the present invention relates to the torque distribution between the left and right front wheels W _FL and W _FR which are driving wheels. The same can be applied. Further, in place of the first hydraulic clutch 3 _L and the second hydraulic clutch 3 _R, it is possible to use other clutch such as an electromagnetic clutch or fluid coupling. Further, in the embodiment, the clutch torque T is dimensionless.
Of correcting longitudinal acceleration Xg 'and the non-dimensional correction lateral acceleration Y
g 'is set as a function of the product Xg' × Yg ',
As a function of the dimensionless correction longitudinal acceleration Xg 'only or
Even if it is set as a function of only the dimensionless correction lateral acceleration Yg ', a sufficient effect can be obtained.

[0049]

As described above, according to the first aspect of the present invention, the left and right front wheels as driving wheels, the left and right rear wheels as driven wheels, the left and right front wheels, and / or the left and right front wheels. Torque distribution means for distributing torque between the rear wheels, longitudinal acceleration calculation means for calculating longitudinal acceleration of the vehicle, and control so that the amount of torque distribution by the torque distribution means increases in accordance with the increase in the calculated longitudinal acceleration. A yaw moment control device for a vehicle, comprising: a torque distribution amount determining means, wherein the torque distribution amount determining means responds to an increase in the longitudinal acceleration of the vehicle.
The front wheel cornering force is reduced and the vehicle
Understeer tendency
In order to compensate for this, the amount of torque distribution is increased more than the value directly proportional to the longitudinal acceleration, so even if the vehicle unexpectedly understeers due to the increase in the longitudinal acceleration of the vehicle, the understeering tendency is compensated for and stable. Turning can be made possible.

According to the invention described in claim 2,
Left and right front wheels as driving wheels, left and right rear wheels as driven wheels, torque distribution means for distributing torque between the left and right front wheels and / or between the left and right rear wheels, and a lateral for calculating the lateral acceleration of the vehicle. A yaw moment control device for a vehicle, comprising: acceleration calculation means; and torque distribution amount determination means for controlling the torque distribution amount by the torque distribution means to increase in accordance with the increase in the calculated lateral acceleration. The means is to generate a front wheel in response to an increase in the lateral acceleration of the vehicle.
Insufficient underground due to lack of nulling force
Compensate for the understeer tendency even if it becomes a tear tendency.
In addition, since the torque distribution is increased more than the value directly proportional to the lateral acceleration, even if the vehicle tends to understeer unintentionally in accordance with the increase in the lateral acceleration of the vehicle, the understeering tendency is compensated for for stable turning. Can be made possible.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a front engine / front drive vehicle equipped with a torque distribution control device.

FIG. 2 is a block diagram showing a circuit configuration of an electronic control unit.

FIG. 3 is a diagram illustrating a yaw moment generated in a turning vehicle.

FIG. 4 is a diagram illustrating a yaw moment generated based on engagement of a hydraulic clutch.

FIG. 5 shows a corrected longitudinal acceleration Xg ′ and a corrected lateral acceleration Yg ′.
Graph showing

FIG. 6 is a view according to a second embodiment of the present invention and corresponding to FIG. 5;

[Explanation of symbols]

Reference Signs List 2 transmission (torque distribution means) 20 longitudinal acceleration calculation means 21 lateral acceleration calculation means 22 torque distribution amount determination means W _FL front wheel W _FR front wheel W _RL rear wheel W _RR rear wheel Xg dimensionless longitudinal acceleration Yg dimensionless lateral acceleration

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-175332 (JP, A) JP-A-4-5130 (JP, A) JP-A-8-121571 (JP, A) JP-A-9-99 86203 (JP, A) US Patent 6,310,154 (US, A) European Patent Application Publication 844129 (EP, A2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 17/20, 23/04

Claims (2)

(57) [Claims] 1. A torque distribution means for distributing torque between left and right front wheels as drive wheels, left and right rear wheels as driven wheels, and between left and right front wheels and / or between left and right rear wheels. A yaw moment control device for a vehicle, comprising: a longitudinal acceleration calculating means for calculating an acceleration; and a torque distribution amount determining means for controlling a torque distribution amount by the torque distribution means to increase in accordance with an increase in the calculated longitudinal acceleration. The torque distribution amount determining means increases the longitudinal acceleration of the vehicle.
The front wheel cornering force decreases accordingly,
Even if unintended understeer tends to occur,
A yaw moment control device for a vehicle , wherein a torque distribution amount is increased to be larger than a value directly proportional to longitudinal acceleration to compensate for the tendency . 2. Torque distribution means for distributing torque between left and right front wheels as drive wheels, left and right rear wheels as driven wheels, and between left and right front wheels and / or between left and right rear wheels. A yaw moment control device for a vehicle, comprising: a lateral acceleration calculating means for calculating an acceleration; and a torque distribution amount determining means for controlling a torque distribution amount by the torque distribution means to increase in accordance with an increase in the calculated lateral acceleration. The torque distribution amount determining means is adapted to increase the lateral acceleration of the vehicle.
Insufficient cornering force to generate front wheels
Even if the vehicle has an unintended understeer tendency,
A yaw moment control device for a vehicle , wherein a torque distribution amount is increased to be larger than a value directly proportional to a lateral acceleration to compensate for a steering tendency .