JPH05262155A - Driving force controller for vehicle - Google Patents

Abstract

PURPOSE:To positively apply a turning moment in the direction for turning to a car body by controlling a lateral distribution quantity setting means and a longitiudinal distribution control quantity setting means on the basis of each set control quantity. CONSTITUTION:A control means 16 is equipped with a lateral distribution control quantity setting means 23 for setting the control quantity of a drive power lateral distribution adjusting means 60 according to the traveling state of a vehicle, and a longitudinal distribution control quantity setting means 21 for setting the control quantity of a drive power longitudinal distribution adjusting means 24 so that the steering characteristic is adjusted in correspondence with the control quantity set by the lateral distribution control quantity setting means 23. Then, the car body is applied with a turning moment in the direction for the turning, by controlling the lateral distribution control quantity setting means 23 and the longitudinal distribution control quantity setting means 21 on the basis of each set control quantity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular driving force control device for controlling a driving state of a vehicle such as an automobile by focusing on yaw rate.

[0002]

2. Description of the Related Art In recent years, a four-wheel drive vehicle (hereinafter referred to as a four-wheel drive vehicle) that drives all four wheels has been actively produced. In such a four-wheel drive vehicle, a front wheel and a rear wheel are used. It is considered to control the distribution of the driving force to and from the wheels so that the driving force can be reliably transmitted to the road surface through each wheel.

On the other hand, it is possible to improve the turning performance by positively controlling the distribution of the driving force between the left and right wheels during turning. Specifically, the turning performance of the vehicle can be improved by distributing more driving force to the outer wheel side of the vehicle than to the inner wheel side. In addition, there are effects such as improvement of vehicle controllability near the limit when turning, and it is possible to improve the yaw response when the steering angle is given to the vehicle by operating the steering wheel not only when turning. It is possible to improve the driving performance itself.

However, such active control of the driving force distribution between the left and right wheels is not yet sufficient, and the development is delayed as compared with the driving force distribution control means between the front and rear wheels.

[0005]

SUMMARY OF THE INVENTION By the way, in a vehicle drive device capable of controlling the driving force distribution between the left and right wheels in addition to the driving force distribution between the front and rear wheels, the driving force distribution control between the front and rear wheels and the left and right wheels are performed. It can be expected that the turning performance and acceleration performance of the vehicle will be significantly improved by combining this with the driving force distribution control. In this case, how to associate the front and rear wheel driving force distribution control with the left and right wheel driving force distribution control is a problem.

The present invention was devised in view of the above problems, and an object thereof is to provide a vehicle driving force control device capable of reliably improving the turning performance and turning performance of a vehicle. And

[0007]

Therefore, in the vehicle drive force control apparatus according to the present invention as set forth in claim 1, in the drive force distribution apparatus for a four-wheel drive vehicle, the drive force from the engine is applied to the front and rear wheels. And a driving force front / rear distribution adjusting means for distributing and adjusting the driving force front / rear distribution adjusting means, the rear wheel driving force distributed through the driving force front / rear distribution adjusting means to the left and right rear wheels, and the above driving force front / rear distribution. Adjusting means and control means for controlling the operation of the driving force left / right distribution adjusting means, and the control means sets left / right distribution for setting the control amount of the driving force left / right distribution adjusting means in accordance with the driving state or running state of the vehicle. Control amount setting means, and front / rear distribution control amount setting means for setting the control amount of the driving force front / rear distribution adjusting means so as to adjust the steer characteristic in accordance with the control amount set by the left / right distribution control amount setting means. Provided, based on the control amount of these settings are characterized by that it is configured to control the right and left distribution control amount setting means and the longitudinal distribution control amount setting means described above.

According to a second aspect of the present invention, there is provided a vehicle driving force control device for a four-wheel drive vehicle, wherein the four-wheel drive type vehicle driving force control device distributes and adjusts the driving force from the engine to the front and rear wheels. Distribution adjusting means, driving force left / right distribution adjusting means for distributing and adjusting the rear wheel driving force distributed through the driving force front / rear distribution adjusting means, the driving force front / rear distribution adjusting means and driving force left / right distribution A steering angle detecting means for detecting a steering angle of the vehicle, a vehicle speed detecting means for detecting a vehicle speed of the vehicle, and a yaw rate detecting for detecting an actual yaw rate of the vehicle. Target yaw rate calculation means for calculating the target yaw rate of the vehicle based on the steering angle information and the vehicle speed information detected by the detection means. , A left / right distribution control amount setting means for setting a control amount of the driving force left / right distribution adjusting means so as to bring the actual yaw rate closer to the target yaw rate, and a control amount set by the left / right distribution control amount setting means. Front and rear distribution control amount setting means for setting the control amount of the driving force front and rear distribution adjusting means so as to adjust the steering characteristic by
It is characterized in that the left and right distribution control amount setting means and the front and rear distribution control amount setting means are controlled on the basis of these set control amounts.

[0009]

In the vehicle driving force control device according to the above-mentioned claim 1, the left / right distribution control amount setting means sets the control amount of the driving force left / right distribution adjusting means in accordance with the driving state or running state of the vehicle, The front / rear distribution control amount setting means sets the control amount of the driving force front / rear distribution adjusting means so as to adjust the steer characteristic in accordance with the control amount set by the left / right distribution control amount setting means. Then, the control means controls the left / right distribution control amount setting means and the front / rear distribution control amount setting means based on the respective control amounts.

According to another aspect of the present invention, there is provided the vehicle driving force control device in which the target yaw rate calculating means uses the steering angle information detected by the steering angle detecting means and the vehicle speed information detected by the vehicle speed detecting means. The target yaw rate is calculated based on the calculated yaw rate, and the left / right distribution control amount setting means controls the driving force left / right distribution adjusting means while performing feedback so that the actual yaw rate detected by the yaw rate detecting means approaches the target yaw rate. Further, the front / rear distribution control amount setting means sets the control amount of the driving force front / rear distribution adjusting means so as to adjust the steer characteristic in accordance with the control amount set by the left / right distribution control amount setting means. Then, the control means controls the left / right distribution control amount setting means and the front / rear distribution control amount setting means based on the respective control amounts. As a result, the distribution of the driving force of the engine to the left and right wheels and the steering characteristic are adjusted, and the vehicle turns smoothly.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 7 show a vehicle driving force control device as a first embodiment of the present invention. FIG. A schematic diagram showing the schematic configuration of the driving force transmission system of the automobile provided,
2 is a schematic diagram showing the structure of the main part, FIG. 3 is a flowchart showing the operation of the main part, FIGS. 4 to 7 are graphs showing the control characteristics thereof, and FIG. 8 is the second part of the present invention. FIG. 1 is a schematic diagram showing a schematic configuration of a driving force transmission system of a vehicle including a lateral driving force control device for a vehicle as an example.

First, a first embodiment of the present invention will be described. A vehicle driving force transmission system 1 equipped with this vehicle driving force control device has a transmission (not shown) of a rotational driving force (driving torque) from an engine 2. Through the center differential 3 composed of a planetary gear, and the like.
From the front wheel side to the rear wheel side.

In particular, the center differential 3 is provided with a center differential differential limiting mechanism 24 as a driving force front-rear distribution adjusting means capable of appropriately limiting the differential between the front and rear wheels. The differential limiting mechanism 24 is composed of a hydraulic multi-plate clutch here, and can control the distribution of the driving force to the front and rear wheels while limiting the differential between the front and rear wheels according to the supplied hydraulic pressure. , A device for controlling the distribution of the driving force between the front and rear wheels.

In this way, one of the driving forces distributed from the center differential 3 is transmitted to the left and right front wheels 4, 5 through the front differential 10. On the other hand, the other of the driving forces distributed from the center differential 3 is transmitted to the rear differential 11 via the propeller shaft 62, and is transmitted to the left and right rear wheels 6, 7 through the rear differential 11. Reference numeral 25 is a bevel gear mechanism including a drive pinion and a ring gear.

The rear differential 11 is provided with a driving force transmission control mechanism 60 as a driving force left / right distribution adjusting means composed of a speed change mechanism 26 and a multi-plate clutch mechanism 27, and is driven by the rear differential 11 and the driving force transmission control mechanism 60. A force left / right distribution adjusting means is configured. The multi-plate clutch mechanism 27
Is a hydraulic type, and by adjusting the hydraulic pressure, the distribution of the driving force to the left and right wheels can be adjusted.

The hydraulic system of the multi-plate clutch mechanism 27 of the driving force transmission control mechanism 60 is controlled by the controller 16 together with the hydraulic system of the center differential differential limiting mechanism 24 as the driving force front-rear distribution adjusting means. Is becoming That is, the hydraulic system of the multi-plate clutch mechanism 27 and the hydraulic system of the multi-plate clutch mechanism 24 include a hydraulic chamber (not shown) attached to each clutch mechanism, an electric pump 28 and an accumulator 29 that form a hydraulic pressure source, and the hydraulic pressure. And a clutch hydraulic pressure control valve 61 for supplying a required amount to the hydraulic chamber. The opening of the clutch hydraulic pressure control valve 61 is controlled by the controller 16.

The controller 16 controls the opening of the clutch hydraulic control valve 61 based on information from the vehicle speed sensor 17, the steering angle sensor 18, the yaw rate sensor 19, and the like. Here, the main part of the driving force transmission control mechanism 60 will be described. As shown in FIGS. 1 and 2, an input shaft 62A, which is provided at the rear end of the propeller shaft 62 and receives the rotational driving force, and an input shaft 62A. A left wheel rotation shaft (drive shaft for the left rear wheel 6) 14 and a right wheel rotation shaft (drive shaft for the right rear wheel 7) 15 that output the driving force input from 62A are provided. A driving force transmission control mechanism 60 is interposed between the right wheel rotating shaft 15 and the input shaft 62A.

The driving force transmission control mechanism 60 is
The left wheel rotary shaft 14 and the right wheel rotary shaft 1 are configured as follows.
The driving force transmitted to the left wheel rotary shaft 14 and the right wheel rotary shaft 15 can be distributed to a required ratio while allowing a differential with respect to the fifth gear. That is, the transmission mechanism 26 and the multi-disc clutch mechanism 27 are interposed between the left wheel rotary shaft 14 and the input shaft 62A and between the right wheel rotary shaft 15 and the input shaft 62A, respectively. Alternatively, the rotational speed of the right wheel rotary shaft 15 is increased by the speed change mechanism 26 and transmitted to the hollow shaft 63 as a driving force transmission auxiliary member.

The multi-disc clutch mechanism 27 is interposed between the hollow shaft 63 and a differential case (hereinafter abbreviated as differential case) 11A on the input shaft 62A side, and the multi-disc clutch mechanism 27 is engaged. By combining,
Driving force is supplied from the high speed side differential case 11A to the low speed side hollow shaft 63. This is because, as a general characteristic of the clutch plates arranged to face each other, torque is transmitted from a higher speed to a lower speed.

Therefore, for example, when the multi-plate clutch mechanism 27 between the right wheel rotary shaft 15 and the input shaft 62A is engaged, the driving force distributed to the right wheel rotary shaft 15 is input shaft 62A.
The driving force distributed to the left wheel rotary shaft 14 is decreased or increased by this amount, which is increased or decreased by the route from the side.
The above-described speed change mechanism 26 is configured by a so-called double planetary gear mechanism in which two planetary gear mechanisms are connected in series. The speed change mechanism 26 provided on the right wheel rotation shaft 15 will be described as an example as follows. Become.

That is, a first sun gear 26A is fixedly attached to the right wheel rotating shaft 15, and the first sun gear 26A is fixed.
A is meshed with a first planetary gear (planetary pinion) 26B on the outer periphery thereof. The first planetary gear 26B is fixed to the second planetary gear 26D so as to rotate integrally with the second planetary gear 26D, and is pivotally supported on the carrier 26F which is fixed to the casing (fixed portion) and does not rotate via the pinion shaft 26C provided on the carrier. Has been done. As a result, the first planetary gear 26B and the second planetary gear 26D are separated from each other by the pinion shaft 26.
The same rotation is performed around C.

Further, the second planetary gear 26D is
The second sun gear 26E is meshed with a second sun gear 26E pivotally supported by the right wheel rotary shaft 15, and the second sun gear 26E is connected to a clutch plate 27A of the multi-plate clutch mechanism 27 via a hollow shaft 63. The other clutch plate 27B of the multi-plate clutch mechanism 27 is connected to the differential case 11A driven by the input shaft 62A.

In the structure of this embodiment, since the second sun gear 26E is formed to have a smaller diameter than the first sun gear 26A, the rotation speed of the second sun gear 26E is the same as that of the second sun gear 26E through the planetary gears 26B and 26D. The size of the sun gear 26A is larger than that of the first sun gear 26A, and the speed change mechanism 26 functions as a speed increasing mechanism. Therefore, when the rotational speed of the clutch plate 27A is higher than that of the clutch plate 27B and the multi-plate clutch mechanism 27 is engaged, a torque corresponding to the engaged state is input from the right wheel rotary shaft 15 side. It is adapted to be fed to the shaft 62A side. For this reason, the drive torque from the input shaft 62A becomes
Will be distributed more to

On the other hand, the transmission mechanism 26 and the multi-disc clutch mechanism 27 provided on the left wheel rotary shaft 14 are also constructed in the same manner. Therefore, when it is desired to distribute more of the drive torque from the input shaft 62A to the right wheel rotary shaft 15, the multi-plate clutch mechanism 27 on the left wheel rotary shaft 14 side is appropriately engaged according to the degree of distribution (distribution ratio). If it is desired to distribute more to the left wheel rotary shaft 14, the multiple disc clutch mechanism 27 on the right wheel rotary shaft 15 side is appropriately engaged according to the distribution ratio.

At this time, since the multi-plate clutch mechanism 27 is of a hydraulic drive type, the engagement state of the multi-plate clutch mechanism 27 can be controlled by adjusting the magnitude of hydraulic pressure, and the input shaft 62A to the left wheel rotating shaft 14 or The feed amount of the driving force to the right wheel rotating shaft 15 (that is, the left / right distribution ratio of the driving force) can be adjusted with appropriate accuracy. The left and right multi-plate clutch mechanisms 27 are set so as not to be completely engaged, and when one of the left and right multi-plate clutch mechanisms 27 is completely engaged, the other multi-plate clutch mechanism 27 slips. It is happening.

Further, the center differential differential limiting mechanism 24 provided in the center differential 3 will be described. The center differential differential limiting mechanism 24 is constituted by the hydraulic multi-disc clutch as described above, and the hydraulic pressure is reduced. When the multi-plate clutch is supplied and engaged, the rotational driving force from the engine 2 is distributed to the front wheel side drive shafts 12 and 13 and the propeller shaft 62 at 50:50. Further, when the hydraulic pressure is not supplied to the center differential differential limiting mechanism 24, the rotational driving force of the front wheel side drive shafts 12 and 13 and the propeller shaft 62 is distributed to, for example, 30:70.

By the way, the center differential differential limiting mechanism 24 as the driving force front / rear distribution adjusting means and the driving force transmission control mechanism 60 as the driving force left / right distribution adjusting means are controlled by the controller 16 as the control means. It has become. As shown in FIG. 1, this vehicle has a vehicle speed sensor 17 as vehicle speed detecting means for detecting the vehicle speed of the vehicle.
A steering angle sensor 18 as steering angle detection means for detecting the steering angle of the steering wheel, and a yaw rate sensor 19 as actual yaw rate detection means for detecting the actual yaw rate of the vehicle. After the information is input to the controller 16, a required calculation is performed in the controller 16 based on each detection signal, the control amount of each adjusting means 24, 60 is obtained, and the set control signal is set to the clutch. It is sent to the hydraulic control valve 61. Then, according to the map of FIG. 4, a predetermined amount of hydraulic pressure is applied to the center differential limiting mechanism 24 and the multiple disc clutch mechanism 2.
It is designed to be supplied to 7.

The vehicle speed sensor 17 includes the drive shafts 12,
They are provided in the vicinity of 13, 14, 15 respectively, and can detect the rotation state of the drive shafts 12, 13, 14, 15; that is, the wheel speeds of the wheels 4, 5, 6, 7. ing. A part of the controller 16 includes a target yaw rate calculating means 22 for calculating a target yaw rate based on steering angle information and vehicle speed information, and a left / right distribution control amount setting means 23 for setting a control amount of the driving force transmission control mechanism 60. With reference to the yaw rate, a control signal for controlling the driving force distribution of the left and right wheels is output.

That is, the left / right distribution control amount setting means 23
In accordance with the yaw rate deviation and the differential value of the yaw rate deviation, the control command values EL and ER for the left wheel side and the right wheel side are output. The target yaw rate is
The target yaw rate calculation means 22 is calculated based on the steering angle information detected by the steering angle sensor 18 and the vehicle speed information detected by the vehicle speed sensor 17, and the actual yaw rate is detected by the yaw rate sensor 19.

The controller 16 is also provided with front / rear distribution control amount setting means 21. The front / rear distribution control amount setting means 21 sets the control amount of the center differential differential limiting mechanism 24 so as to adjust the steer characteristic of the vehicle in accordance with the control amount set by the left / right distribution control amount setting means 23. It is supposed to do. Regarding the control of the center differential differential limiting mechanism 24 and the driving force transmission control mechanism 60 in the controller 16, for example, a control signal is output while performing feedback from the actual yaw rate and the target yaw rate as shown in the flowchart in FIG. It is like this.

Here, the control by the driving force transmission control mechanism 60 will be described in detail. First, the steering wheel angle (actual steering angle) δf detected by the steering angle sensor 18 and the four wheels detected by the vehicle speed sensor 17 will be described. Wheel speed V4, V5, V
6, V7 and the actual yaw rate Y detected by the yaw rate sensor 19 are input to the controller 16.

Next, the target yaw rate calculation means 22 calculates the target yaw rate Y ^{* according} to the following equation (1). Y ^* = (V · δf) / [L (1 + A · V ² )] (1) where V is the average value of the wheel speeds V4, V5, V6 and V7,
L is the vehicle wheel base, and A is the stability factor. The stability factor A is one of the vehicle speed sensitive elements like the feedback gains G1 and G2 described later, and its value is determined according to the graph shown in the map 1 of FIG. 5, for example. ..

The yaw rate deviation ΔY, which is the deviation between the target yaw rate Y ^* and the actual yaw rate Y, is given by the equation (2).
And the yaw rate deviation differential value Δ
Y'is calculated according to the equation (3). ΔY = Y ^* −Y (2) ΔY ′ = dΔY / dt (3) The left / right distribution control amount setting means 23 uses the yaw rate deviation ΔY and the yaw rate deviation differential value ΔY ′ to determine the command values EL and ER of the control signal by the following equation (3),
The calculation is performed according to (4). EL = G1 × ΔY + G2 × ΔY '... (3) ER = -G1 × ΔY-G2 × ΔY' ... (4) Here, G1 and G2 are feedback This is a speed-sensitive element called gain, and these feedback gains G
For 1 and G2, for example, the values are determined according to the graph shown in the map 2 of FIG.

The command value EL is a control signal sent to the left wheel side, and is a signal indicating the magnitude of the driving force moving to the left wheel side. The command value ER is a control signal sent to the right wheel side, and is a signal indicating the magnitude of the driving force that moves to the right wheel side. Then, the control signals for the above command values EL and ER are sent from the left / right distribution control amount setting means 23 to the clutch hydraulic pressure control valve 61, and a predetermined amount of operating hydraulic pressure is supplied to the multiple disc clutch mechanism 27 according to the map of FIG. It is supposed to be done. Then, such a control operation is repeated in a predetermined cycle.

As a result, control signals of the command values EL and ER are sent from the controller 16 to the clutch hydraulic pressure control valve 61, and a predetermined hydraulic pressure is output to the driving force transmission control mechanism 60 and transmitted to the left wheel and the right wheel. The driving force is adjusted to the required state, and the driving force is distributed according to the driving state of the vehicle. Here, the command values EL, E
The driving force corresponding to the R control signal is determined by, for example, the map shown in FIG. In this map, the neutral dead zone width α is provided, and the command value EL,
When the ER is a small value in the dead band, the driving force distribution between the left and right wheels is not changed.

The neutral dead zone is provided in a region where EL and ER are near 0, and each sensor 17,
When noise is mixed in the signals input to 18 and 19 due to disturbance from the road surface or the like, excessive control of a minute control signal output by the noise is suppressed to stabilize the control. It is provided for. Therefore, when EL and ER are small values near 0, the drive torque corresponding to the command values EL and ER of the control signal is set to 0 and the drive force distribution between the left and right wheels is not changed. ing.

In this way, the distribution of the driving force between the left and right wheels is determined, and the driving force transmission control mechanism 60 is controlled. Then, the driving force front / rear distribution adjusting means 24
The control of the control signal command value EL,
After the ER is calculated, the front-rear wheel rotation difference ΔV _FR is calculated, for example, according to the following equation (5). ΔV _FR = [2 · (V1 + V2) / (V1 + V2 + V3 + V4)]-1.0 ... (5) Note that the front-rear wheel rotation difference ΔV _FR calculated by the equation (5).
Is calculated here as a slip ratio indicating how much the front wheels slip with respect to the rear wheels.

Then, the positive / negative of the actual yaw rate Y and the positive / negative of the command values EL and ER of the control signal are judged. Here, in this flowchart, it is assumed that the vehicle is turning right when Y> 0. When the actual yaw rate Y is determined to be positive, that is, the vehicle is determined to be in the right turn state, and the command value ER of the control signal is determined to be positive, the front / rear distribution control amount setting means 21 The command value EC of the control signal of the center differential differential limiting mechanism 24 is set using the map 2 of FIG.

When the command value ER of the control signal is determined to be negative, the front / rear distribution control amount setting means 21 uses the map 1 of FIG. 7 to set the command value EC of the control signal of the center differential differential limiting mechanism 24. It is supposed to be set. Here, when the command value ER of the control signal is positive, the driving force is moved to the right wheel side as described above, and this is the actual behavior of the vehicle when the vehicle is turning right. Indicates that there is an oversteering tendency, and the left / right distribution control amount setting means 23 is controlling so that ER> 0 in order to suppress this.

For this reason, the center differential differential limiting mechanism 24 is adjusted by the command value EC of the control signal set by the front / rear distribution control amount setting means 21 to increase the driving force distribution on the front wheels, thereby understeering the vehicle. To steer the vehicle to a neutral steer, for example. Further, when the command value ER of the control signal is negative, the actual behavior of the vehicle is an understeer tendency contrary to the above. Then, in order to suppress this, the right / left distribution control amount setting means 23 is controlling so that ER <0.

Therefore, the center differential differential limiting mechanism 24 is adjusted by the command value EC of the control signal set by the front / rear distribution control amount setting means 21 to increase the driving force distribution on the rear wheel side. Oversteer is promoted so that the steer characteristic of the vehicle becomes neutral steer, for example. On the other hand, when the actual yaw rate Y is determined to be negative, that is, when the vehicle is determined to be turning left, if the command value EL of the control signal is a positive value, the front / rear distribution control amount setting means 21. Is configured to set the command value EC using the map 2 in FIG.

If the command value EL of the control signal is determined to be negative at this time, the front / rear distribution control amount setting means 21 sets EC using the map 1 in FIG. Here, when the command value EL of the control signal is positive, the driving force is moved to the left wheel side, as described above. This means that when the vehicle is turning left, the actual behavior of the vehicle is oversteer. There is a tendency, and the left and right distribution control amount setting means 23 is controlling so that EL> 0 in order to suppress this.

For this reason, the center differential differential limiting mechanism 24 is adjusted by the command value EC of the control signal set by the front / rear distribution control amount setting means 21 to increase the driving force distribution on the front wheels, thereby understeering the vehicle. To steer the vehicle to a neutral steer, for example. Further, when the command value EL of the control signal is negative and the actual vehicle behavior is an understeer tendency contrary to the above, the left and right distribution control amount setting means 23 becomes EL <0 in order to suppress this. It is when you are controlling.

Therefore, the center differential differential limiting mechanism 24 is adjusted by the command value EC of the control signal set by the front / rear distribution control amount setting means 21 to increase the driving force distribution on the rear wheel side. Oversteer is promoted so that the steer characteristic of the vehicle becomes neutral steer, for example. Then, as described above, after the command value EC is set by the front-rear distribution control amount setting means 21, the control signal EC of the center differential differential limiting mechanism 24 is output. Here, the transmission torque of the center differential differential limiting mechanism 24 is determined according to, for example, the map shown in FIG. Here, the relationship between the control signal EC and the transmission torque is linear, but the characteristics of the map in FIG. 6 do not necessarily have to be linear.

The maps 1 and 2 shown in FIG. 7 will be described. Map 1 shows that when the vehicle is understeered, the center differential differential limiting mechanism 2 is calculated from the front / rear wheel rotation difference ΔV _FR.
It is a map which sets the control signal EC of No. 4. The map 1 is provided with a neutral dead zone width, and the front and rear wheel rotation difference Δ
When V _FR has a small value in the dead zone, the driving force distribution between the front and rear wheels is not changed.

Further, this map 1 is set so that the control characteristics thereof change with the values of EL and ER as parameters, and as the value of EL and ER increases, the neutral dead zone width increases, and Absolute value of front-rear wheel rotation difference | ΔV
The increase rate of the EC value to be set decreases with respect to the increase rate of _FR | (that is, the gradient of the graph of map 1 becomes gentle).

This is because the control amount of the center differential differential limiting mechanism 24 may be small when the vehicle is understeered. Therefore, the larger the values of EL and ER, the smaller the value of EC is set. It is like this.
On the other hand, map 2 is a map for setting the control signal EC of the center differential differential limiting mechanism 24 from the front-rear wheel rotation difference ΔV _FR when the vehicle is in the oversteering tendency.

The map 2 is also provided with the neutral dead zone width as in the case of the map 1, and when the front and rear wheel rotation difference ΔV _FR is a small value in the dead zone, the driving force distribution between the front and rear wheels is distributed. It does not change. Further, this map 2 is set so that the control characteristics thereof change with the values of EL and ER as parameters. When the value of EL and ER increases, the neutral dead zone width decreases and the front and rear wheels rotate. With respect to the increase rate of the absolute value | ΔV _FR | of the difference, the set EC value rapidly increases (that is, the gradient of the graph of the map 2 becomes steep).

This is because when the vehicle tends to oversteer, the control amount of the center differential differential limiting mechanism 24 needs to be large. Therefore, the larger the values of EL and ER, the larger the value of EC is set. It is like this. As described above, the command value EC of the control signal to the center differential differential limiting mechanism 24 as the driving force front-rear distribution adjusting means is sent from the controller 16 to the clutch hydraulic pressure control valve 61, and a predetermined operating hydraulic pressure is applied to the center differential differential limiting mechanism. 24
Is output to.

Then, the driving force on the front wheel side and the driving force on the rear wheel side are adjusted to a predetermined state, and the driving force distribution corresponding to the driving state of the vehicle is performed. Since the vehicle driving force control device as the first embodiment of the present invention is configured as described above, for example, when the vehicle turns, the vehicle is driven by the left / right distribution control amount setting means 23 according to the flowchart of FIG. The force transmission control mechanism 60 is controlled to adjust the left-right driving force distribution on the rear wheel side. At this time, when the drive torque moves to the inner wheel side, it means that the vehicle tends to oversteer. Therefore, the center differential differential limiting mechanism 24 is controlled according to the map 2 of FIG. 7 so as to make the steer characteristic a neutral steer. .. That is, the center differential differential limiting mechanism 24 sets the driving force distribution between the front wheels and the rear wheels to, for example, 50:50 to promote the understeer tendency.

Further, when the driving force transmission control mechanism 60 is controlled according to the flow chart of FIG. 3 and the driving torque is moved to the outer wheel side, the vehicle is in the understeer tendency, so the front / rear distribution control amount setting means 21 The center differential differential limiting mechanism 24 is controlled by the map 1 of FIG. 7 so as to cancel this understeer tendency. Specifically, the driving force distribution on the rear wheel side is increased to promote the oversteering tendency.

Here, the control flow of the driving force transmission control mechanism 60 in the flow chart shown in FIG. 3 will be described. First, in step S1, the steering wheel angle (actual steering angle) δf, the wheel speeds of the four wheels V4, V5, V6. Each of V7 and the actual yaw rate Y is input to the controller 16. Next, in step S2, the target yaw rate calculation means 22 calculates the target yaw rate Y ^{* according} to the above-mentioned formula (1).

Then, in step S3, the yaw rate deviation ΔY which is the deviation between the target yaw rate Y ^* and the actual yaw rate Y is calculated by the equation (2), and the yaw rate deviation differential value ΔY 'is calculated by the equation (3). Is calculated. Then, in step S4, the yaw rate deviation Δ
By using Y and the yaw rate deviation differential value ΔY ′, the command values EL and ER of the control signals are set by the left / right distribution control amount setting means 23.
For example, it is calculated according to equations (3) and (4) shown below.

Then, in step S5, the control signals for the command values EL and ER are sent from the left / right distribution control amount setting means 23 to the clutch hydraulic pressure control valve 61, and a predetermined amount of hydraulic pressure is increased according to the map of FIG. It is adapted to be supplied to the plate clutch mechanism 27. Then, such control operation is repeated in a predetermined cycle. As a result, the control signals of the command values EL and ER are sent from the controller 16 to the clutch hydraulic pressure control valve 61, a predetermined operating hydraulic pressure is output to the driving force transmission control mechanism 60, and the driving force transmitted to the left wheel and the right wheel. Is adjusted to the required state, and the driving force is distributed according to the driving state of the vehicle.

In this way, the distribution of the driving force between the left and right wheels is determined in S1 to S5 of the flowchart shown in FIG.
The driving force transmission control mechanism 60 is controlled. Next, a flow for setting the control amount of the center differential limiting mechanism 24 in the flowchart shown in FIG. 3 will be described. After step S4, according to a flowchart (S6 to S12) different from the driving force transmission control mechanism 60. The control amount of the center differential limiting mechanism 24 is set.

That is, after the command values EL and ER of the control signal are calculated in step S4, the front-rear wheel rotation difference ΔV _FR (slip ratio) is calculated in accordance with the above-mentioned equation (5), for example. Then, in step S7, it is determined whether the actual yaw rate Y input in step S1 is positive or negative. Here, in this flowchart, Y> 0
At this time, the vehicle is turning right.

When it is determined in step S7 that the actual yaw rate Y is positive, that is, when the vehicle is making a right turn, it is determined in step S8 whether the command value ER of the control signal is positive or negative. At this time, if the command value ER of the control signal is determined to be positive in step S8, the center differential differential limiting mechanism 2 is used in step S10 using the map 2 of FIG.
The command value EC of the control signal 4 is set.

Further, in step S8, the command value E of the control signal
When R is determined to be negative, the command value EC of the control signal of the center differential differential limiting mechanism 24 is set using the map 1 of FIG. 7 in step S11. Then, when it is determined in step S7 that the actual yaw rate Y is negative, that is, when the vehicle is in the left-turning state, it is determined in step S9 whether the command value EL of the control signal is positive or negative. At this time, if the command value EL of the control signal is determined to be positive in step S9,
In step S10, the command value EC is set using the map 2 in FIG.

In step S9, the control signal command value E
If L is determined to be negative, EC is set using the map 1 of FIG. 7 in step S11. Then, as described above, in step S10 or step S11, the command value E
After C is set, the control signal EC of the center differential limiting mechanism 24 is output in step S12. Here, the transmission torque of the center differential differential limiting mechanism 24 is determined according to, for example, the map shown in FIG.

By the above-mentioned operation, the command value EC of the control signal to the center differential limiting mechanism 24 is changed to the controller 16.
Is transmitted to the clutch hydraulic pressure control valve 61, and a predetermined hydraulic pressure is output to the center differential differential limiting mechanism 24. Then, the driving force on the front wheel side and the driving force on the rear wheel side are adjusted to a predetermined state, and the driving force distribution corresponding to the driving state of the vehicle is performed.

Since the present device operates as described above, when the vehicle turns, the yaw rate of the vehicle is fed back so as to approach the target yaw rate, and the wheels on the inner wheel side and the wheels on the outer wheel side are fed depending on the steering state of the vehicle. Since the driving force transmitted is adjusted, a turning moment in the direction of turning is applied to the vehicle body. Further, the driving force distribution of the front and rear wheels is controlled by appropriately adjusting the center differential differential limiting mechanism 24. As a result, a larger turning yaw moment is generated.

In this way, since the turning moment in the direction of turning is applied to the vehicle body, the turning performance of the vehicle is improved. By appropriately setting the target yaw rate, the turning characteristic of the vehicle can be made to be an ideal steer characteristic such as neutral steer. For example, when a turning operation is performed while the vehicle is being driven, the driving force to the turning inner wheel side is reduced, the driving force to the turning outer wheel side is increased, and a turning moment in the direction of turning is given to the vehicle body.

On the other hand, when a turning operation is performed while the vehicle is being braked, a driving force to the turning inner wheel side (the driving force in this case is a negative value, that is, a braking force in a state where the engine brake acts). As a result, the driving force (that is, the braking force) to the outer wheel turning side is increased to decrease, and a turning moment in the direction of turning is given to the vehicle body. Further, since the command value EC of the control signal of the center differential differential limiting mechanism 24 is set in correspondence with the driving force distribution of the left and right wheels, more accurate driving force distribution can be performed.

Further, it is possible to sufficiently improve the turning characteristic only by the yaw rate deviation without feeding back the driving torque and the rotational speed. Further, although the present embodiment has been described using a four-wheel drive vehicle equipped with the center differential 3, a mechanism similar to the center differential differential limiting mechanism 24 capable of adjusting the driving force on the front wheel side and the rear wheel side. If it is provided, the vehicle driving force control device can be used for a four-wheel drive vehicle that is not provided with the center differential 3.

Next, the second embodiment of the present invention will be described. Here, the configuration of the driving force front / rear distribution adjusting means and the driving force left / right distribution adjusting means is different from that of the first embodiment. As shown in FIG. 8, a vehicle driving force transmission system 1 including the vehicle driving force control device is configured by planetary gears through which a rotational driving force (driving torque) from an engine 2 is transmitted through a transmission (not shown) or the like. The center differential 3 receives and transmits from the center differential 3 to the front wheel side and the rear wheel side.

The center differential 3 is also provided with a multi-plate clutch mechanism 64 as a driving force front-rear distribution adjusting means capable of appropriately limiting the differential between the front and rear wheels. The multi-plate clutch 64 can control the distribution of the driving force to the front and rear wheels while limiting the differential between the front and rear wheels according to the supplied hydraulic pressure. In this way, one of the driving forces distributed from the center differential 3 is transmitted to the left and right front wheels 4, 5 through the front differential 10. On the other hand, the other of the driving forces distributed from the center differential 3 is transmitted to the rear differential 11 via the propeller shaft 62, and the rear differential 1
1 is transmitted to the left and right rear wheels 6, 7.

A driving force transmission control mechanism 65 as a driving force left / right distribution adjusting means composed of a multi-plate clutch mechanism 27 is provided in the rear differential 11. The multi-disc clutch mechanism 27 is also of a hydraulic type, and the distribution of the driving force to the left and right wheels can be adjusted by adjusting the hydraulic pressure. Then, the multi-plate clutch mechanism 2 of the driving force transmission control mechanism 65
The hydraulic system 7 is controlled by the controller 16 together with the hydraulic system of the multi-plate clutch mechanism 64 as the driving force front-rear distribution adjusting means.

The controller 16 controls the multiple disc clutch mechanisms 27 and 64 based on information from the vehicle speed sensor 17, the steering angle sensor 18, the yaw rate sensor 19, and the like. Here, the main part of the driving force transmission control mechanism 65 will be described. As shown in FIG. 8, the driving force transmission control mechanism 65 is interposed between the left wheel rotary shaft 14, the right wheel rotary shaft 15, and the propeller shaft 62. It is equipped.

The driving force transmission control mechanism 65 is
The left wheel rotary shaft 14 and the right wheel rotary shaft 1 are configured as follows.
The driving force transmitted to the left wheel rotary shaft 14 and the right wheel rotary shaft 15 can be distributed to a required ratio while allowing a differential with respect to the fifth gear. That is, the multi-disc clutch mechanism 27 is interposed between the left wheel rotary shaft 14 and the propeller shaft 62 and between the right wheel rotary shaft 15 and the propeller shaft 62, and the multi-disc clutch mechanism 27 is engaged. By doing so, the driving force distributed to the left wheel rotary shaft 14 and the right wheel rotary shaft 15 is adjusted.

At this time, since the multi-plate clutch mechanism 27 is of a hydraulic drive type, the engagement state of the multi-plate clutch mechanism 27 can be controlled by adjusting the magnitude of hydraulic pressure, and the propeller shaft 62 to the left wheel rotary shaft 14 or The feed amount of the driving force to the right wheel rotating shaft 15 (that is, the left / right distribution ratio of the driving force) can be adjusted with appropriate accuracy. The left and right multi-plate clutch mechanisms 27 are set so as not to be completely engaged with each other.
When one of them is completely engaged, the other multi-disc clutch mechanism 2
7 is designed to cause slippage.

Further, the multi-disc clutch mechanism 64 provided along with the center differential 3 will be described. The multi-disc clutch mechanism 64 is composed of the hydraulic multi-disc clutch as described above, and supplies the hydraulic pressure. When the lever multiple disc clutch is completely engaged, the rotational driving force from the engine 2 is applied to the front wheel side drive shafts 12 and 13 and the propeller shaft 6.
It is distributed to 2 and 50:50. When the hydraulic pressure is not supplied to the multi-plate clutch mechanism 64,
The rotational driving force between the front wheel side drive shafts 12 and 13 and the propeller shaft 62 is distributed to, for example, 30:70.

By the way, the multi-plate clutch mechanism 64 as the driving force front / rear distribution adjusting means and the multi-plate clutch mechanism 27 as the driving force left / right distribution adjusting means are controlled by the controller 16 as the control means. ing. The control of the multi-disc clutch mechanisms 27, 64 is controlled by the same method as that of the first embodiment, and the description thereof is omitted here.

Since the present device is configured as described above, when the vehicle turns, the yaw rate of the vehicle is fed back so as to approach the target yaw rate, and the wheels on the inner wheel side are slowly rotated according to the steering state of the vehicle. Since the wheels on the outer wheel side are rotated quickly, a turning moment in the direction of turning is given to the vehicle body. Further, by appropriately adjusting the multi-plate clutch mechanism 64 provided along with the center differential 3, the driving force distribution of the front and rear wheels is controlled. As a result, a larger turning yaw moment is generated.
In this way, since the turning moment in the direction in which the vehicle is about to turn is applied to the vehicle body, the turning performance of the vehicle is improved.

By appropriately setting the target yaw rate, the turning characteristic of the vehicle can be made an ideal steer characteristic such as neutral steer. Further, the command value EC of the control signal of the center differential limiting mechanism 24 is
Since it is set according to the driving force distribution of the left and right wheels,
Accurate driving force distribution can be performed.

Further, it is possible to sufficiently improve the turning characteristic only by the yaw rate deviation without feeding back the driving torque and the rotational speed.

[0076]

As described above in detail, according to the present invention as set forth in claim 1, in a driving force distribution device for a four-wheel drive vehicle, the driving force from the engine is distributed and adjusted to the front and rear wheels. Driving force front / rear distribution adjusting means, driving force left / right distribution adjusting means for distributing and adjusting the rear wheel driving force distributed through the driving force front / rear distribution adjusting means, and the driving force front / rear distribution adjusting means and drive Control means for controlling the operation of the force left / right distribution adjusting means, and the control means sets left / right distribution control amount setting means for setting the control amount of the driving force left / right distribution adjusting means in accordance with the driving state or traveling state of the vehicle. When,
Front-rear distribution control amount setting means for setting the control amount of the driving force front-rear distribution adjusting means so as to adjust the steering characteristic in accordance with the control amount set by the left-right distribution control amount setting means. The above-mentioned left and right distribution control amount setting means and the front-rear distribution control amount setting means are controlled based on the respective controlled amounts, so that when the vehicle turns, the wheels on the inner wheel side and the wheels on the outer wheel side according to the steering state of the vehicle. By adjusting the driving force transmitted to the vehicle and the vehicle body, it is possible to positively give the vehicle body a turning moment in the direction of turning.

Further, by controlling the driving force distribution of the front and rear wheels, a larger turning yaw moment can be generated and the turning performance of the vehicle can be improved. further,
Since the command value of the control signal of the front / rear distribution control amount setting means is set corresponding to the driving force distribution of the left and right wheels, more accurate driving force distribution can be performed. Further, according to the present invention as set forth in claim 2, in a drive force distribution device provided for a four-wheel drive vehicle, a drive force front / rear distribution adjusting means for distributing and adjusting the drive force from the engine to the front and rear wheels, and this drive. A driving force left / right distribution adjusting unit that distributes and adjusts the rear wheel driving force distributed through the force front / rear distribution adjusting unit, and controls the operation of the driving force front / rear distribution adjusting unit and the driving force left / right distribution adjusting unit. A control means is provided, and a steering angle detection means for detecting a steering angle of the vehicle, a vehicle speed detection means for detecting a vehicle speed of the vehicle, and a yaw rate detection means for detecting an actual yaw rate of the vehicle are provided. A target yaw rate calculating means for calculating a target yaw rate of the vehicle based on the steering angle information and the vehicle speed information detected by each of the detection means; and the actual yaw rate as the target. A left / right distribution control amount setting means for setting a control amount of the driving force left / right distribution adjusting means so as to approach the yaw rate, and a steer characteristic is adjusted corresponding to the control amount set by the left / right distribution control amount setting means. And a front-rear distribution control amount setting means for setting a control amount of the driving force front-rear distribution adjusting means, and the left-right distribution control amount setting means and the front-rear distribution control amount setting means based on each of the set control amounts. When the vehicle turns, the yaw rate of the vehicle is fed back so as to approach the target yaw rate, and the driving force transmitted to the inner wheel side wheel and the outer wheel side wheel is adjusted according to the steering state of the vehicle. Thus, the turning moment in the direction of turning can be applied to the vehicle body.

Furthermore, the driving force distribution between the front and rear wheels is controlled by appropriately adjusting the driving force front-rear distribution adjusting means.
By generating a larger turning yaw moment, the turning performance of the vehicle can be improved. Further, since the command value of the control signal of the driving force front-rear distribution adjusting means is set in correspondence with the driving force distribution of the left and right wheels, more accurate driving force distribution can be performed.

Further, since the turning moment in the direction of turning is applied to the vehicle body, the turning performance of the vehicle is improved. And by setting the target yaw rate appropriately,
The turning characteristic of the vehicle can be made an ideal steer characteristic such as neutral steer.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a vehicle showing a schematic configuration of a driving force transmission system in an automobile having a vehicle driving force control device as a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a main configuration of a vehicle driving force control device as a first embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the vehicle driving force control device as the first embodiment of the present invention.

FIG. 4 is a map (graph showing control characteristics) relating to control amount setting in the vehicle driving force control apparatus as the first embodiment of the present invention.

FIG. 5 is a map (graph showing control characteristics) relating to control amount setting in the vehicle driving force control apparatus as the first embodiment of the present invention.

FIG. 6 is a map (graph showing control characteristics) relating to control amount setting in the vehicle driving force control apparatus as the first embodiment of the present invention.

FIG. 7 is a map (graph showing control characteristics) relating to control amount setting in the vehicle driving force control apparatus as the first embodiment of the present invention.

FIG. 8 is a schematic diagram of a vehicle showing a schematic configuration of a driving force transmission system in an automobile having a vehicle driving force control device as a second embodiment of the present invention.

[Explanation of reference numerals] 1 driving force transmission system 2 engine 3 center differential 4,5 front wheel 6,7 rear wheel 8 front wheel side output shaft 8A front wheel side drive gear 9 rear wheel side output shaft 9A rear wheel side drive gear 10 front differential 11 Rear differential 11A Rear differential case 12,13 Front wheel side drive shaft 14,15 Rear wheel side drive shaft 16 Controller as control means 17 Vehicle speed sensor 18 Steering angle sensor 21 Front / rear distribution control amount setting means 22 Target yaw rate calculating means 23 Left / right distribution control amount Setting means 24 Center differential limiting mechanism as driving force front-rear distribution adjusting means 25 Bevel gear mechanism 26 Transmission mechanism 26A First sun gear 26B First planetary gear 26C Pinion shaft 26D Second planetary gear 26E Second sun gear 26F Carrier 27 Multi-plate Ku Mechanism 27A, 27B clutch plate 28 electric pump 29 accumulator 30, 40, 50 continuously variable transmission (CVT) 31, 32, 41, 42, 51, 52 driven gear 33, 34, 43, 44, 53, 54 pulley 33A, 34A, 43A, 44A, 53A, 54A Pulley groove parts 35, 45, 55 Steel belt 60 Driving force transmission control mechanism as driving force left / right distribution adjusting means 61 Clutch hydraulic control valve 62 Propeller shaft 62A Input shaft 63 Hollow shaft 64 Drive Multi-disc clutch mechanism as force front / rear distribution adjusting means 65 Driving force transmission control mechanism as driving force left / right distribution adjusting means

Claims (2)

[Claims] 1. A driving force distribution device for a four-wheel drive vehicle, wherein a driving force front / rear distribution adjusting means for distributing and adjusting a driving force from an engine to front and rear wheels and the driving force front / rear distribution adjusting means are distributed. The control means includes a driving force left / right distribution adjusting means for distributing and adjusting the rear wheel driving force to the left and right rear wheels, and a control means for controlling the operation of the driving force front / rear distribution adjusting means and the driving force left / right distribution adjusting means. Corresponding to the left and right distribution control amount setting means for setting the control amount of the driving force left and right distribution adjusting means according to the driving state and running state of the vehicle, and the control amount set by the left and right distribution control amount setting means. Front-rear distribution control amount setting means for setting the control amount of the driving force front-rear distribution adjusting means so as to adjust the steer characteristic, and the left-right distribution control amount setting means based on each of the set control amounts. And a driving force distribution device for a vehicle, which is configured to control the front-rear distribution control amount setting means. 2. A drive force distribution device for a four-wheel drive vehicle, wherein a drive force front / rear distribution adjusting means for adjusting and adjusting a drive force from an engine to front and rear wheels, and the drive force front / rear distribution adjusting means are distributed. The vehicle includes the driving force left / right distribution adjusting means for adjusting the distribution of the rear wheel driving force to the left and right rear wheels, and the control means for controlling the operation of the driving force front / rear distribution adjusting means and the driving force left / right distribution adjusting means. Steering angle detecting means for detecting the steering angle of the vehicle, vehicle speed detecting means for detecting the vehicle speed of the vehicle, and yaw rate detecting means for detecting the actual yaw rate of the vehicle. Target yaw rate calculating means for calculating the target yaw rate of the vehicle based on the detected steering angle information and vehicle speed information, and the actual yaw rate approaching the target yaw rate. As described above, the left / right distribution control amount setting means for setting the control amount of the driving force left / right distribution adjusting means, and the driving force front / rear so as to adjust the steering characteristic in accordance with the control amount set by the left / right distribution control amount setting means With front and rear distribution control amount setting means for setting the control amount of the distribution adjusting means,
A driving force distribution device for a vehicle, characterized in that it is configured to control the left-right distribution control amount setting means and the front-rear distribution control amount setting means based on these set control amounts.