JP4895043B2 - Vehicle driving force control device - Google Patents

Description

  The present invention relates to a driving force control device for a vehicle, and more particularly to a technique for improving running safety when the vehicle is traveling straight.

  In recent years, the difference in rotation between the left and right wheels has been suppressed when the vehicle is running straight by controlling the amount of driving force distribution, which is mainly provided between the left and right wheels of the rear wheel, and is controlled by the movement of the driving force between the left and right rear wheels. Left and right wheel driving force distribution means that can improve the turning performance by ensuring driving stability and generating a driving force difference between the left and right wheels during turning, so-called active yaw control system (hereinafter referred to as AYC). Has been developed (see Patent Document 1).

Also, in order to prevent the driving force from being transmitted due to idling (slip) of each wheel of the vehicle, when the slip of the wheel is detected, the driving force (engine torque) of the engine that is the driving source is suppressed or slipped. A driving force control means that suppresses the slip by applying a braking force to the existing wheel, a so-called traction control system (hereinafter referred to as TCL) has been developed (Patent Document 2).
JP-A-5-345534 Japanese Patent No. 2993400

In the left and right wheel driving force distribution control by AYC as disclosed in Patent Document 1, generally, the driving force distribution control mode is selectively set according to the road surface friction coefficient (road surface μ) and the like, and the low μ road surface mode is set. If there is, the driving force distribution amount is reduced, and if it is the high μ road surface mode, the driving force distribution amount is controlled to be larger.
However, when the driving force distribution control mode is not appropriately selected for the actual road surface μ, there is a problem that the driving force control is not performed well.

  For example, if the rotational speed of one of the left and right rear wheels increases due to slip or the like during straight traveling, AYC moves the driving force to the other wheel having a lower rotational speed to reduce the rotational difference between the left and right wheels. However, if the high μ road surface mode is selected even though the actual road surface is a low μ road surface, an excessive driving force moves to the other wheel. For this reason, the other wheel slips or the like and the rotational speed increases, thereby the direction of movement of the driving force reverses and the rotational speed of one wheel increases again. In this way, repeated driving force movement of AYC, that is, hunting, may cause vibration in the vehicle, yaw motion in the vehicle, and the like, which may impair the running stability of the vehicle.

  Further, when a vehicle having both AYC and TCL as disclosed in Patent Documents 1 and 2 travels on a split road surface, if a wheel on the low μ road surface slips, AYC becomes a wheel on the high μ road surface side. While moving the driving force, braking force is applied to the wheel slipped by TCL. For this reason, the driving force of the wheels on the high μ road surface side that is not slipping becomes excessive compared to the low μ road surface side, and an excessive yaw motion may occur in the vehicle, which may impair running stability.

  The present invention has been made to solve such problems, and the object of the present invention is to optimize the control of AYC and TCL during straight running and improve running stability in a vehicle equipped with AYC and TCL. An object of the present invention is to provide a driving force control device for a vehicle that can be used.

  In order to achieve the above object, in the vehicle driving force control apparatus according to claim 1, when the idling of the wheel is detected by the idling detecting means for detecting idling of the wheel of the vehicle, and when the idling of the wheel is detected by the idling detecting means, Driving force control means for controlling the driving force of the vehicle to suppress idling, and left and right wheel driving force distribution means for transmitting the driving force from the driving source of the vehicle to the left and right wheels with a variable amount of predetermined driving force distribution Driving force distribution amount control means for controlling the predetermined driving force distribution amount in the left and right wheel driving force distribution means so as to reduce the rotation difference between the left and right wheels when the vehicle is traveling straight ahead, and the driving force distribution amount The control means is characterized in that when the driving force control is performed by the driving force control means, the predetermined driving force distribution amount is suppressed and controlled.

According to a second aspect of the present invention, there is provided the vehicle driving force control device according to the first aspect, wherein the driving force control means suppresses the driving force generated by the driving source of the vehicle and controls the idling wheels detected by the idling detection means. The driving force of the vehicle is controlled by performing at least one of the power application.
According to a third aspect of the present invention, there is provided the vehicle driving force control device according to the second aspect, wherein the driving force control means suppresses the driving force generated by the vehicle driving source and controls the idling wheels detected by the idling detection means. In the case where both of power are applied, the driving force generated by the driving source of the vehicle is suppressed before the braking force is applied to the idling wheel.

  According to a fourth aspect of the present invention, there is provided a driving force control apparatus for a vehicle according to any one of the first to third aspects, wherein the driving force distribution amount control means sets a calculation parameter for calculating the predetermined driving force distribution amount according to a road surface friction coefficient. As described above, when the driving force control by the driving force control means is performed, the predetermined driving force distribution amount is suppressed by switching to a calculation parameter corresponding to the lowest road surface friction coefficient.

According to the vehicle driving force control apparatus of the present invention using the above means, the driving force distribution amount control means determines the predetermined driving force distribution amount in the left and right wheel driving force distribution means according to the driving state of the vehicle. In addition to control, during driving force control by the driving force control means, a predetermined driving force distribution amount in the left and right wheel driving force distribution means is controlled to be suppressed.
That is, when the idling of the wheel is suppressed by the driving force control means, the driving force movement amount between the left and right wheels can be suppressed, and an excessive driving force can be prevented from being generated in one wheel.

As a result, for example, in a vehicle equipped with driving force control means and left and right wheel driving force distribution means, it is possible to suppress hunting of driving force movement during low μ road running, excessive yaw movement during split road running, etc. , Running stability can be improved.
According to the vehicle driving force control apparatus of the second aspect, the driving force control means performs at least one of the suppression of the driving force generated by the driving source and the application of the braking force to the idling wheel. Idling can be suppressed.

According to the vehicle driving force control device of the third aspect, the driving force control means controls the driving force generated by the driving source of the vehicle before applying the braking force to the idling wheel. Can be suppressed in a stable state.
According to the vehicle driving force control apparatus of the fourth aspect, the driving force distribution amount suppression control by the driving force distribution amount control means is switched to the calculation parameter corresponding to the lowest road surface friction coefficient to obtain a predetermined driving force distribution amount. Calculate.
Thereby, the amount of driving force distribution can be suppressed with simple control.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Referring to FIG. 1, a schematic configuration diagram of a vehicle driving force control device according to the present invention is shown, and with reference to FIG. 2, a block diagram of a vehicle driving force control device according to the present invention is shown.
A vehicle 1 shown in FIG. 1 has an engine (drive source) 2 mounted at the front of the vehicle body as a drive source, and has left front wheels 4L, right front wheels 4R (also referred to as front wheels 4), left rear wheels 6L as drive wheels, The vehicle is a four-wheel drive vehicle including right rear wheel 6R (also referred to as rear wheel 6).

A transmission 10 is connected to the engine 2, and the transmission 10 is connected to a center differential 12.
The center differential 12 is disposed on the axle of the front wheel 4 and has a function of distributing driving force to the front wheel 4 side and the rear wheel 6 side.
The center differential 12 is also connected to a front differential 14 that is disposed on the axle of the front wheel 4.

The front differential 14 has a function of distributing the driving force distributed to the front wheel 4 side by the center differential 12 to the left front wheel 4L and the right front wheel 4R.
The center differential 12 is also connected to one end of the propeller shaft 16. The propeller shaft 16 is connected to an active yaw control differential (right and left wheel driving force distribution means) 18 (hereinafter referred to as AYC differential) at the other end, and the driving force distributed to the rear wheel 6 side by the center differential 12 is applied to the AYC. It has a function of transmitting to the differential 18.

The AYC differential 18 is provided on the axle of the rear wheel 6 and has a function of distributing the driving force transmitted from the propeller shaft 16 to the left rear wheel 6L and the right rear wheel 6R according to the driving state of the vehicle 1. is doing.
Specifically, the AYC differential 18 transmits the driving force input from the propeller shaft 16 to the respective axles of the left and right rear wheels 6L and 6R while allowing a rotational difference between the left and right rear wheels 6L and 6R. And a driving force transmission control mechanism that distributes the driving force of the left and right rear wheels 6L, 6R by moving one driving force of the left and right rear wheels 6L, 6R to the other driving force. 18b. The driving force transmission control mechanism 18b includes an acceleration / deceleration mechanism 18c that accelerates and decelerates one of the left and right rear wheels 6L and 6R relative to the other wheel, and a first transmission that transmits rotation on the acceleration side to the other wheel. 1 clutch mechanism 18d and the 2nd clutch mechanism 18e which transmits the rotation by the side of deceleration to the other wheel are comprised.

Further, the wheels 4L, 4R, 6L, and 6R of the vehicle 1 are respectively provided with brakes 20L, 20R, 22L, and 22R that apply braking force to the wheels 4L, 4R, 6L, and 6R.
Furthermore, wheel speed sensors 24L, 24R, 26L, and 26R that detect wheel speeds are provided on the wheels 4L, 4R, 6L, and 6R.

The vehicle 1 is provided with an AYC ECU 28 that controls the AYC differential 18 and a traction control ECU 30 (hereinafter referred to as a TCL ECU) that controls the engine 2 and the brakes 20L, 20R, 22L, and 22R. .
The AYC ECU 28 includes wheel speed sensors 26L and 26R for the left and right rear wheels 6L and 6R, and a driver having a high μ road surface mode (for example, a paved road), a medium μ road surface mode (for example, an unpaved road), and a low μ road surface mode (for example, A mode changeover switch 32 capable of selecting a control mode corresponding to three types of road surface conditions (freezing road) is electrically connected.

The AYC ECU 28 is electrically connected to an AYC hydraulic unit 34 that adjusts the hydraulic pressure to the first and second clutch mechanisms 18d and 18e of the AYC differential 18, and the AYC hydraulic unit 34 is connected to the AYC hydraulic unit 34. Thus, the first and second clutch mechanisms 18d and 18e are controlled, that is, the AYC differential 18 is controlled.
On the other hand, the TCL ECU 30 is electrically connected to the wheel speed sensors 24L, 24R, 26L, 26R of the wheels 4L, 4R, 6L, 6R and the front-rear G sensor 36 for detecting the front-rear acceleration acting on the vehicle 1. ing.

The TCL ECU 30 is electrically connected to the engine 2 and a brake hydraulic unit 38 that adjusts the hydraulic pressure to the brakes 20L, 20R, 22L, and 22R. Torque) and the braking force of each brake 20L, 20R, 22L, 22R is controlled via the brake hydraulic unit 38.
Further, the AYC ECU 28 and the TCL ECU 30 are also electrically connected.

The AYC ECU 28 and the TCL ECU 30 are also connected with other sensors such as a yaw rate sensor, a lateral G sensor, and a handle angle sensor (not shown).
Hereinafter, the input / output relationship of the AYC ECU 28 and the TCL ECU 30 will be described with reference to FIG.
The AYC ECU 28 is connected to the mode selector switch 32 and the left and right rear wheels 6L and 6R wheel speed sensors 26L and 26R on the input side, and to the output side to the AYC differential 18 via the AYC hydraulic unit 20. ing.

Specifically, the wheel speed sensors 36L and 36R are connected to the rear wheel left / right rotation difference calculation unit 40 in the ECU 28 for AYC.
The rear wheel left / right rotation difference calculation unit 40 calculates the rear wheel left / right rotation difference from the wheel speeds detected by the left rear wheel 6L and the right rear wheel 6R detected by the wheel speed sensors 36L, 36R.
The rear wheel left / right rotation difference calculation unit 40 is connected to a driving force movement amount calculation unit (driving force distribution amount control means) 42 in the AYC ECU 22 together with the mode switch 24.

The driving force movement amount calculation unit 42 stores driving force movement amount calculation parameters in advance corresponding to the control modes that can be selected by the mode switch 24.
Then, the driving force movement amount calculation unit 42 uses the driving force movement amount calculation parameter of the control mode selected by the mode switch 24 to calculate the rear wheel left / right rotation difference calculated by the rear wheel left / right rotation difference calculation unit 40. Accordingly, the driving force movement amount necessary to reduce the left-right rotation difference is calculated. The driving force movement amount is calculated using, for example, the driving force movement amount calculation parameter in the low μ road mode than the case where the driving force movement amount calculation parameter in the high μ road mode is used. The amount is set to be low.

The driving force movement amount calculation unit 42 is connected to the AYC differential 18 via the AYC hydraulic unit 20 so that the driving force movement amount calculated by the driving force movement amount calculation unit 42 becomes the AYC differential. 18 is controlled.
On the other hand, the TCL ECU 32 is connected to the wheel speed sensors 34L, 34R, 36L, 36R and the front and rear G sensors 38 of the wheels 4L, 4R, 6L, 6R on the input side, the engine 2 on the output side, and the brake The brakes 26L, 26R, 28L, and 28R are connected via the hydraulic unit 30.

Specifically, the wheel speed sensors 34L, 34R, 36L, and 36R are connected to the vehicle body speed estimation unit 50 and the wheel slip amount estimation unit 52 in the TCL ECU 30, and the longitudinal G sensor 38 is connected to the vehicle body speed estimation unit 50. Has been.
The vehicle body speed estimation unit 50 estimates the vehicle body speed from the wheel speeds detected by the wheel speed sensors 34L, 34R, 36L, 36R and the front-rear G detected by the front-rear G sensor 38.

The vehicle body speed estimation unit 50 is connected to the wheel slip amount estimation unit 52 and the road surface friction coefficient estimation unit 54.
The wheel slip amount estimation unit 52 detects a wheel slip from the wheel speed detected by each wheel speed sensor 34L, 34R, 36L, 36R and the vehicle body speed estimated by the vehicle body speed estimation unit 50, and the wheel slip is detected. The amount is estimated (wheel idling detection means). The detection of the wheel slip and the estimation of the wheel slip amount are performed based on, for example, the difference between the vehicle speed estimated from the wheel speed and the vehicle speed estimated from the front and rear G.

The wheel slip amount estimation unit 52 is connected to a road surface friction coefficient estimation unit 54 and a TCL control amount calculation unit 56.
In the road surface friction coefficient estimating unit 54, the friction coefficient (road surface μ) of the road surface on which the vehicle 1 is traveling is calculated from the vehicle body speed estimated by the vehicle body speed estimating unit 50 and the wheel slip amount estimated by the wheel slip amount estimating unit 52. Presumed.

The road surface friction coefficient estimating unit 54 is connected to the TCL control amount calculating unit 56.
The TCL control amount calculation unit 56 calculates the TCL control amount of the vehicle 1 from the wheel slip amount estimated by the wheel slip amount estimation unit 52 and the road surface friction coefficient estimated by the road surface friction coefficient estimation unit 54. Specifically, as the TCL control amount, the engine torque suppression amount of the engine 2 for suppressing the wheel slip and the brake braking force amount to the slip wheel are calculated.

The TCL control amount calculation unit 56 is connected to the brake control unit 58 and the engine control unit 60 in the TCL ECU 32.
The brake control unit 58 controls the brakes 20L, 20R, 22L, and 22R of the slip wheels via the brake hydraulic unit 30 so that the brake braking force amount calculated by the TCL control amount calculation unit 56 is obtained.

On the other hand, the engine control unit 60 controls the engine torque of the engine 2 in accordance with the engine torque suppression amount calculated by the TCL control amount calculation unit 56. The engine torque suppression control of the engine control unit 60 is set to be executed before the brake control of the brake control unit 58.
Further, the engine control unit 60 is also connected to the driving force movement amount calculation unit 42 in the AYC ECU 22, and the engine control unit 60 starts the engine torque suppression control of the engine 2 and is turned on from the OFF state. A TCL control flag for switching to the state is output to the driving force movement amount calculation unit 42.

Then, when the TCL control flag is switched to the ON state, the driving force movement amount calculation unit 42 performs the suppression control of the driving force movement amount.
The suppression control of the driving force movement amount in the driving force movement amount calculation unit 42 corresponds to, for example, a lower road friction coefficient than the driving force movement amount calculation parameter in the low μ road surface mode that can be selected by the mode changeover switch 32. The driving force movement amount calculation parameter for the extremely low μ road surface mode is stored in advance, and the ultra low μ road surface mode is switched to when the TCL control flag is turned on.

That is, when the TCL control is performed in the TCL ECU 30, the driving force movement control by the AYC ECU 28 is suppressed to a value lower than usual.
The operation of the vehicle driving force control apparatus according to the present invention thus configured will be described below.
Referring to FIGS. 3 and 4, FIG. 3 shows a time chart when the vehicle equipped with the driving force control device according to the present invention travels on a low μ road surface, and FIG. 4 shows the driving force control according to the present invention. Explanatory drawing which shows the control state at the time of split road driving | running | working of the vehicle provided with the apparatus is shown.

First, a control state when the vehicle travels on a low μ road surface in a state where the mode changeover switch 32 is set to the high μ road surface mode will be described with reference to FIG.
In the time chart of FIG. 3, each state of the driving force movement amount calculation parameter, each wheel speed, the driving force movement amount calculated by the AYC ECU 28, the yaw rate of the vehicle 1, and the TCL control flag in the TCL ECU 30 is shown in time series. Is shown in

The vehicle 1 starts on a low μ road surface with the mode changeover switch 32 set to the high μ road surface mode.
Immediately after the vehicle 1 starts moving, vibrations occur in the wheels 4L, 4R, 6L, and 6R, and then the wheel speed gradually increases.
At time t1, the TCL ECU 30 detects a slip of the vehicle 1, and engine torque suppression control is performed by the TCL ECU 30. At the same time, since the TCL control flag is switched from OFF to ON, the driving force movement amount calculation unit 42 of the AYC ECU 28 that has received the TCL control flag switches the driving force movement amount calculation parameter from the high μ road surface mode to the very low μ road surface mode. .

  On the other hand, in the conventional control indicated by the chain line in FIG. 3, the vehicle travels with the driving force movement amount in the high μ road surface mode after the time t1. When a difference in rotation occurs between the left and right rear wheels 6L and 6R at time t2, excessive driving force movement calculated by the driving force movement amount calculation parameter corresponding to the high μ road surface occurs, and hunting of the driving force movement occurs. . Specifically, when the wheel speed of the left rear wheel 6L becomes higher than that of the right rear wheel 6R at time t2, an excessive driving force moves to the right rear wheel 6R via the AYC differential 18, and the right rear wheel 6R slips. Etc., and the wheel speed increases. As a result, an excessive driving force moves from the right rear wheel 6R to the left rear wheel 6R, and hunting occurs due to the repetition of such driving force movement. Then, due to the hunting of the driving force movement, the vehicle 1 slightly swings left and right as indicated by the yaw rate of the vehicle 1, and the traveling of the vehicle 1 becomes unstable.

  On the other hand, in the vehicle driving force control device according to the present invention, the driving force is not moved or the driving force is moved by switching to the driving force movement amount calculation parameter corresponding to the extremely low μ road surface after time t1. In this case, the amount of movement of the driving force is sufficiently suppressed. In other words, it is possible to prevent the wheel to which the driving force has been moved from slipping, thereby suppressing the hunting of the driving force movement amount.

Next, a control state when the vehicle 1 travels on a so-called split road surface having different left and right road surface friction coefficients will be described with reference to FIG.
In FIG. 4, the left side of the vehicle 1 is a split road surface having a high μ road surface and the right side is a low μ road surface, and the mode selector switch 32 is set to a low μ road surface mode.
If the right rear wheel 6R on the low μ road surface slips while the vehicle 1 is traveling on the split road surface, the TCL ECU 30 first suppresses the engine torque of the engine 2 and brakes the right rear wheel 6R that is a slip wheel. A braking force is applied by 22R.

Further, the TCL control flag of the TCL ECU 30 is turned ON, and the driving force movement amount calculation unit 42 of the AYC ECU 28 that has received the TCL control flag changes the driving force movement amount calculation parameter from the low μ road surface mode to the extremely low μ road surface mode. Switch to.
On the other hand, in the conventional control indicated by the chain line in FIG. 3, the AYC ECU 28 uses the driving force transfer amount calculation parameter in the low μ road surface mode to reduce the rotational difference between the left and right rear wheels 6L and 6R. The amount is calculated, and the driving force moves to the left rear wheel 6L via the AYC differential 18 with the driving force moving amount. At this time, since the braking force also acts on the right rear wheel 6R by the control of the TCL ECU 30, the driving force of the left rear wheel 6L becomes excessive with respect to the right rear wheel 6R. For this reason, an excessive yaw motion occurs counterclockwise as viewed from above in the vehicle 1.

On the other hand, in the vehicle driving force control apparatus according to the present invention, the left rear wheel 6L is switched to the extremely low μ road surface mode that calculates the driving force movement amount lower than the low μ road surface mode. The driving force movement amount is suppressed. Thereby, the driving force of the left rear wheel 6L is suppressed, and the yaw motion generated in the vehicle 1 can be suppressed.
As described above, in the vehicle driving force control apparatus according to the present invention, the engine control unit of the TCL ECU 30 and the driving force movement amount calculation unit of the AYC ECU 28 are connected, and the engine torque suppression control by the TCL ECU 30 is started. In addition, by suppressing the driving force movement amount in the AYC ECU 28, it is possible to prevent hunting of the driving force movement amount and yaw motion during split road surface travel, and to stabilize the vehicle traveling performance.

This is the end of the description of the embodiment of the vehicle driving force control apparatus according to the present invention, but the embodiment is not limited to the above embodiment.
In the above embodiment, the driving force moving amount is suppressed by switching the driving force moving amount parameter of the AYC ECU 28 to the extremely low μ road surface mode in accordance with the TCL control flag from the engine control unit of the TCL ECU 30. However, the means for suppressing the driving force movement amount is not limited to this. For example, according to the engine torque suppression amount controlled by the TCL ECU or the brake braking force control amount, the AYC ECU is instructed to determine the driving force movement amount by the AYC differential 18 or the upper limit value of the driving force movement amount. It doesn't matter.

  In the above-described embodiment, the suppression control of the driving force movement amount of the AYC ECU 28 is started in accordance with the TCL control flag from the engine control unit 60 of the TCL ECU 30. The start determination means is not limited to the TCL control flag. For example, the estimated road surface friction coefficient and the TCL ECU are controlled according to the vehicle speed, front / rear G yaw rate or yaw rate change rate, steering angle or tire turning angle, lateral G, split road surface determination, electronically controlled four-wheel drive control amount. It may also be determined from the brake operation status, the engine torque suppression amount by the TCL ECU, the accelerator opening, the engine torque, the transmission gear information, the transmission control mode, and the like.

1 is a schematic configuration diagram of a vehicle driving force control apparatus according to the present invention. 1 is a block diagram of a driving force control apparatus for a vehicle according to the present invention. 4 is a time chart when the vehicle provided with the driving force control apparatus according to the present invention is traveling on a low μ road surface. It is explanatory drawing which shows the control state at the time of split road driving | running | working of the vehicle provided with the driving force control apparatus which concerns on this invention.

Explanation of symbols

1 vehicle 2 engine (drive source)
4L, 4R, 6L, 6R Wheel 18 Active yaw control differential (AYC differential) (right and left wheel drive force distribution means)
20L, 20R, 22L, 22R Brake 24L, 24R, 26L, 26R Wheel speed sensor 28 ECU 28 for AYC (drive force distribution amount control means)
30 TCL ECU 30 (driving force control means)
32 Mode change switch 34 AYC hydraulic unit 36 Front / rear G sensor 38 Brake hydraulic unit 40 Rear wheel left / right rotation difference calculation unit 42 Driving force movement amount calculation unit 50 Vehicle body speed estimation unit 52 Wheel slip amount estimation unit (idling detection means)
54 Road Surface Friction Coefficient Estimator 56 TCL Control Amount Calculator 58 Brake Controller 60 Engine Controller

Claims (4)

Wheel idling detection means for detecting idling of a vehicle wheel;
Driving force control means for controlling the driving force of the vehicle so as to suppress the idling when the idling of the wheel is detected by the idling detection means;
Left and right wheel driving force distribution means for transmitting the driving force from the driving source of the vehicle to the left and right wheels with a variable amount of predetermined driving force distribution;
Driving force distribution amount control means for controlling the predetermined driving force distribution amount in the left and right wheel driving force distribution means so as to reduce the rotation difference between the left and right wheels when the vehicle is traveling straight ahead;
The drive force control apparatus for a vehicle according to claim 1, wherein the drive force distribution amount control means suppresses the predetermined drive force distribution amount when the drive force control is performed by the drive force control means.   The driving force control unit controls the driving force of the vehicle by performing at least one of suppression of driving force generated by the driving source of the vehicle and application of braking force to the idling wheel detected by the idling detection unit. The driving force control apparatus for a vehicle according to claim 1.   The driving force control means generates the vehicle driving source when both the suppression of the driving force generated by the vehicle driving source and the application of the braking force to the idling wheel detected by the idling detection means are performed. 3. The vehicle driving force control device according to claim 2, wherein the driving force is suppressed before the braking force is applied to the idling wheel.   The driving force distribution amount control means has two or more calculation parameters for calculating the predetermined driving force distribution amount in accordance with a road surface friction coefficient, and the driving force control by the driving force control means is performed. 4. The vehicle driving force control device according to claim 1, wherein the predetermined driving force distribution amount is suppressed by switching to a calculation parameter corresponding to the lowest road surface friction coefficient.

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