JPH05201325A - Vehicle slip control device - Google Patents

Abstract

PURPOSE:To prevent a driver from feeling physical disorder in the operation of a brake pedal when he changes the step from an accelerator pedal to a brake pedal, in adjusting brake force and controlling traction. CONSTITUTION:The traction control by the adjustment of brake force is inhibited when the operation cancellation of the an accelerator pedal 10 is detected by a sensor S5 or when the fault of the sensor S5 is detected, by providing the sensor S5 for detecting the cancellation of the operation of the accelerator pedal 10 and a fault detecting means 55 for detecting the fault of the sensor S5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle slip control device.

[0002]

2. Description of the Related Art A slip control device for a vehicle detects the slip amount of the drive wheel in order to prevent the drive wheel from slipping due to an excessive drive torque during acceleration of the vehicle to reduce the acceleration performance. It is generally known that the engine control for reducing the engine output and the brake control for controlling the braking force of the driving wheels are performed so that the slip amount becomes the target slip amount.

In controlling the engine output, when the amount of depression of the accelerator pedal becomes small, the engine output torque is reduced in conjunction with the depression of the accelerator pedal, so that the driver's accelerator operation can be immediately changed to the driving state of the vehicle. There is a proposal to reflect it (Japanese Patent Laid-Open No. 63-
38063).

[0004]

With respect to the above-mentioned brake control, when the brake pedal is changed from the accelerator pedal, the depression of the brake pedal is detected and the brake control is stopped. Since the braking force still remains due to the brake control, it is easy for the driver to feel discomfort when depressing the brake pedal. In particular, in a type in which brake control is performed using a vacuum booster that assists the pedal effort of the brake pedal, it is difficult to rapidly increase the brake force when the brake pedal is depressed.

That is, in the above type,
Negative pressure is introduced into each of the first and second chambers partitioned by the diaphragm, and the atmosphere is introduced into the second chamber when the brake pedal is depressed or when the brake is controlled, so that the pressure difference between the two chambers is increased. As a result, the depression force of the brake pedal is assisted via the diaphragm. Then, when the brake control is released, the negative pressure of the negative pressure source is introduced into the second chamber instead of the atmosphere through the first chamber. Until the introduction of the negative pressure is completed, the negative pressure in the first chamber is temporarily reduced. Therefore, even if the atmosphere is introduced into the second chamber by depressing the brake pedal, the negative pressure in the first chamber is lowered, so that the braking force is gradually increased.

To solve this problem, when the accelerator pedal is released, the sensor detects it and the brake control is immediately stopped.
However, although the above problem can be solved by doing so, it may be considered that the accelerator pedal depression detection sensor malfunctions.

[0007] Therefore, the present invention addresses the above-mentioned problems in consideration of the failure of the sensor.

[0008]

Means for Solving the Problem and Its Action The present invention is
For such a problem, the brake control is prohibited when the release of the operation of the accelerator means of the engine is detected by the sensor, and the brake control is also prohibited when the failure of the sensor is detected. It is a thing.

That is, the means for solving the above problem is a vehicle provided with a brake control means for controlling the braking force applied to the drive wheels so that the slip amount of the drive wheels with respect to the road surface during acceleration of the vehicle becomes a target value. Of the slip control device, a sensor for detecting the release of the operation of the accelerator means of the engine, a failure detecting means for detecting the failure of the sensor, a detection of the release of the operation of the accelerator means by the sensor, and the failure detecting means. And a brake control restricting unit that prohibits the operation of the brake control unit when at least one of the detection of the failure of the sensor by the sensor is performed.

In such a means, when the release of the operation of the accelerator means is detected by the sensor, the brake control by the brake control means is immediately prohibited, and the application of the braking force to the drive wheels is released. Therefore, when the driver depresses the accelerator pedal to the brake pedal, the application of the braking force by the brake control means has already been released, so the driver can only use his / her intention, that is, only operate the brake pedal. The braking force can be adjusted so that the driver does not feel uncomfortable when the brake pedal is depressed.

Thus, even when the sensor fails, the brake control is prohibited as in the case where the release of the operation of the accelerator is detected. Therefore, when the brake pedal is depressed, the drive wheel is already depressed. The situation in which the braking force is applied does not occur, and the driver can perform the brake operation without feeling a sense of discomfort in the brake pedal.

The failure detecting means is one that judges a failure when the sensor detects the deactivation of the accelerator means while the vehicle is accelerating, and the sensor is detected when the vehicle is decelerating. Failure is determined when the accelerator release is not detected, and a failure is detected when a signal for detecting the release of the accelerator release is continuously output from the sensor for a predetermined time or more (chattering). Judgment, judgment of failure when detecting disconnection or short circuit of the transmission line of the sensor, further failure when the sensor detects deactivation of the accelerator means even when the brake control amount is large It is possible to apply various things such as the one that is determined to be.

Further, in the above problem solving means, the engine control means for controlling the engine output so that the slip amount of the drive wheels with respect to the road surface becomes the target value without being restricted by the control by the brake control restricting means. Is preferably provided separately. That is, in this case, even if the brake control is prohibited due to the malfunction of the sensor, the engine control means can operate, and therefore, when the vehicle accelerates, the slip amount of the drive wheels, which is the original purpose of the slip control device, is increased. Can be controlled, which is advantageous in terms of ensuring good acceleration.

The difference between the friction coefficient detecting means for detecting the friction coefficient of the left and right portions of the road surface on which the left and right driving wheels roll and the friction coefficient of the left and right portions of the road surface detected by the friction coefficient detecting means is a predetermined value. It is also preferable to provide a split road determination means that determines that the road surface is a split road in the above case and prohibits the operation of the brake control restriction means.

In this way, the operation of the brake control means has priority over the operation of the brake control restriction means on the split road. Therefore, on a split road, even if the operation of the accelerator is released during brake control or the sensor that detects this release fails, the brake control will be continued and the behavior stability of the vehicle will be ensured. Will be advantageous.

Further, as the drive source of the brake in the above-mentioned brake control, the first chamber into which the negative pressure of the negative pressure source is introduced and the second chamber in which the negative pressure of the first chamber and the atmosphere are switched and introduced.
A chamber and a diaphragm separating the first chamber and the second chamber from each other, and when the brake pedal is stepped on, the introduction into the second chamber is switched from negative pressure to the atmosphere to assist the pedaling force of the brake pedal via the diaphragm. A vacuum booster is used to introduce the atmosphere into the second chamber when the brake force is controlled by the brake control means, and the second chamber is used when the brake force is not controlled.
In the case where the introduction switching means for introducing the negative pressure of the first chamber is separately provided in the chamber, the brake pedal is started because the introduction of the negative pressure to the second chamber is started at the same time as the operation of the accelerator means is released. It becomes possible to terminate the introduction of the negative pressure when the vehicle is stepped on, and to secure the negative pressure that can obtain the desired braking force in the first chamber, and it is easy to secure the braking force during sudden braking. become.

[0017]

Therefore, according to the present invention, the operation of the brake control means is prohibited when the release of the operation of the accelerator means is detected by the sensor or the failure of the sensor is detected by the failure detecting means. Since the brake control restricting means is provided, it is possible to avoid the situation where the brake pedal is stepped on while the braking force is being applied to the drive wheels, and the driver can feel the brake pedal without feeling discomfort. You will be able to perform operations.

Further, according to the present invention, there is provided engine control means for reducing the engine output so that the slip amount of the drive wheels with respect to the road surface becomes a target value without being restricted by the control by the brake control restriction means. For example, even if the brake control is prohibited due to a malfunction of the sensor, the slip control can be continued during acceleration of the vehicle, and good acceleration can be ensured.

Further, when the difference between the friction coefficients on the left and right sides of the road surface detected by the friction coefficient detecting means is equal to or greater than a predetermined value, the road surface is judged to be a split road and the split road is prohibited from operating. According to the device provided with the judging means, on the split road, even if the operation of the accelerator means is released during the brake control or the sensor for detecting the release fails, the brake control can be continued, Can be prevented from becoming unstable.

Further, even in the case where the vacuum booster for assisting the pedaling force of the brake pedal is utilized to obtain the braking force during the brake control, the driver does not feel uncomfortable in the operation of the brake pedal, and It becomes easy to obtain the desired braking force.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 1FL is a left front wheel, 1FR is a right front wheel, 1RL is a left rear wheel, and 1RR is a right rear wheel. The engine 2 is mounted horizontally on the front part of the vehicle body, and the torque generated by the engine 2 is transmitted to the clutch 3, the transmission 4, and the differential gear 5, and then the left front wheel 1FL is passed through the left drive shaft 6L. To the right front wheel 1FR via the right drive shaft 6R. In this way, the vehicle has front wheels 1F.
L and 1FR are the driving wheels, and the rear wheels 1RL and 1RR are the driven wheels, which are the driven wheels.

Brake 7FL to 7R mounted on each wheel
R is a hydraulic disc brake.
In addition, the master cylinder 8 as a brake fluid pressure generation source
Is a tandem type having two discharge ports 8a and 8b. The brake pipe 13 extending from one discharge port 8a of the master cylinder 8 is branched into two in the middle,
The branch pipe 13F is connected to the left front wheel brake 7FL (the wheel cylinder mounted inside the caliper), and the branch pipe 13R is connected to the right rear wheel brake 7RR.
The branch pipe 14 extending from the other discharge port 8b of the master cylinder 8 is also branched into two, the branch pipe 14F is connected to the right front wheel brake 7FR, and the branch pipe 14R is connected to the left rear wheel brake 7RL. ..

Branch pipe 13 for front wheels, that is, for drive wheels
Electromagnetic hydraulic pressure adjusting valve 15L or 1 is provided on F and 14F.
5R is connected, and an electromagnetic opening / closing valve 16L or 16R is connected to the branch pipes 13R and 14R for the rear wheels. The hydraulic pressure adjusting valves 15L and 15R are the brake 7FL,
The brake fluid pressure supply from the master cylinder 8 to the 7FR and the brake fluid pressure of the brakes 7FL and 7FR are connected to the pipe 2
The mode of switching to the reservoir tanks 22L and 22R via 1L and 21R is switched. The brake fluid in the reservoir tank 21L is returned to the pipe 13 by the pump 23L via the pipe 25L to which the check valve 24L is connected. Similarly, the brake fluid in the reservoir tank 22R is pumped by the pump 23L.
By R, the check valve 24R is returned to the pipe 14 via the pipe 25R to which the check valve 24R is connected.

The stepping force on the brake pedal 12 is
It is transmitted to the master cylinder 8 via a booster or brake booster 11. This booster 11 is basically the same as a known vacuum booster, but when performing slip control, as will be described later, it is possible to obtain a braking force even when the brake pedal is not depressed. It is configured to be able to.

The booster 11 has a case 31 fixed to the vehicle body and the master cylinder 8, and inside the case 31, a first chamber 34 and a second chamber are formed by a diaphragm 32 and a valve body 33 fixed to the diaphragm 32. 35. The negative pressure of the negative pressure source (for example, the intake negative pressure of the engine 2) is always supplied to the first chamber 34, and the second chamber 35 is the first chamber 3 when the brake pedal is not depressed.
4 is communicated with the booster 11 and the operation of the booster 11 is stopped. Then, when the brake pedal 12 is depressed, atmospheric pressure is supplied to the second chamber 35, whereby the diaphragm 32 is displaced forward together with the valve body 33, and a boosting action is obtained.

The switching between the negative pressure supply and the atmospheric pressure supply to the second chamber 35 is basically performed by the valve device provided in the valve body 33. This valve body 33
The part will be described with reference to FIG.

First, the valve body 33 has a power piston 41 fixed to the diaphragm 32, and a reaction disc 42 and a base end portion of the output shaft 43 are provided in a recess 41a formed in the power piston 41. It is fitted. The output shaft 43 serves as an input shaft of the master cylinder 8. A valve plunger 45 is attached to the tip of the input shaft 44 connected to the brake pedal 12 inside the valve body 33. A vacuum valve 46 is arranged behind the valve plunger 45.

The power piston 41 has a pressure introducing passage 50.
The pressure introducing passage 50 is always communicated with the space X formed around the valve plunger 45. This space X is always communicated with the second chamber 35. A valve seat 47, on which the vacuum valve 46 is seated, is formed at the end of the pressure introducing passage 50 that opens toward the space X. In addition, the vacuum valve 46 is a valve plunger 45.
The valve seat 45a formed at the rear end is also seated on and off.

In the above structure, it is assumed that a negative pressure is being introduced into the pressure introducing passage 50. In this state, when the brake pedal 12 is not depressed, the vacuum valve 46 is seated on the valve seat 45a by the urging force of the springs 48 and 49 in the state of FIG. 2, but is separated from the valve seat 47. There is. Therefore, the pressure introducing passage 5
The negative pressure from 0 is introduced into the second chamber 35 through the space X, and the boosting action is not performed.

When the brake pedal 12 is depressed,
The input shaft 44 and hence the valve plunger 45 are moved forward (moved leftward in the drawing). During this forward movement, the vacuum valve 46
Is first seated on the valve seat 47, and the space X and the pressure introducing passage 50 are
Communication with the vacuum valve 46 and then the valve seat 45
a is separated. By separating the vacuum valve 46 and the valve seat 45a, the atmospheric pressure from the rear of the valve body 33 is introduced into the space X, and the second chamber 35 becomes the atmospheric pressure. As a result, the diaphragm 32 is displaced forward together with the valve body 33, and as a result, the output shaft 43 moves forward and a boosting action is performed. The brake reaction force from the master cylinder 8 is transmitted to the valve plunger 45 and thus the brake pedal 12 via the reaction disc 42.
When the depression operation force of the brake pedal 12 is released, the return spring 36 (see FIG. 1) returns to the state of FIG. 2 to prepare for the next boosting action.

The part described above is the same as the known vacuum booster, but in the present embodiment, the negative pressure of the first chamber 34 is introduced into the pressure introducing passage 50 for slip control. The state and the state where atmospheric pressure is introduced are switched. That is, the first chamber 34 and the pressure introducing passage 5
0 is connected via a pipe 37, and a three-way electromagnetic switching valve (introduction switching means) 38 is connected to the pipe 37 (FIG. 1).
reference). This switching valve 38 has a pressure introducing passage 50 when demagnetized.
Is communicated with the first chamber 34, and atmospheric pressure is introduced into the pressure introduction passage 50 during excitation. When the switching valve 38 is excited and the atmospheric pressure is introduced into the pressure introducing passage 50, the space X and therefore the second chamber 35 becomes the atmospheric pressure even if the brake pedal 12 is not depressed, and as a result, A brake fluid pressure is generated in the master cylinder 8 by a boosting action.

Next, the control system will be described. The control system is
It is configured using a microcomputer, and is shown in FIG.
In the figure, 51 is a control means for performing engine control and brake control. The control means 51 includes each wheel 1F.
The signals from the sensors S1 to S4 that detect the rotation speeds of L to 1RR and the signal from the brake control restricting means 53 are input.

The control means 51 is for detecting friction coefficient of the road surface, friction coefficient detecting means, control target value setting means, slip amount detecting means, slip determining means, control amount calculating means, and engine output and brake control. An output means is provided, and from this control means 51, engine output adjusting means 9 for engine control, hydraulic pressure adjusting valves 15L, 15R for brake control, and on-off valves 16L, 1 are provided.
A control signal is output to the 6R and the switching valve 38. The engine output adjusting means 9 adjusts the engine output by driving a sub-throttle valve (not shown) provided in the intake passage in addition to the main throttle valve that interlocks with the accelerator pedal 10.

The brake control restricting means 53 includes an idle switch S5 for detecting the release of the operation of the accelerator pedal (accelerating means of the engine 2), a failure detecting means 55 for detecting a failure of the idle switch S5, and a split road. Each signal from the determination means 54 is input.
Further, the failure detecting means 55 includes an idle switch S
5 and the signal from the control means 51 are input.

A detailed description will be given below. [Detection of road friction coefficient] The friction coefficient detecting means detects the friction coefficient of the left and right portions of the road on which the left and right drive wheels 1FL and 1FR roll, and the detection is performed by the corresponding left and right driven wheels 1RL. , 1RR wheel speed Vr and its acceleration VG
And based on.

First, a timer A is used to calculate the acceleration VG.
(100 msec count) and timer B (500 msec count) are used. That is, the acceleration VG is the wheel speed Vr for 100 msec every 100 msec from the start of slip control until 500 msec has elapsed (acceleration is not sufficiently large).
Calculated by the following equation (1) based on the change of (unit: km / h), and 100 after 500 msec (acceleration is fully developed)
Based on the change of the wheel speed Vr for 500 msec every msec,
It is calculated by equation (2).

-(1) Formula-VG = Gk1 × {Vr (k) -Vr (k-100)}-(2) Formula-VG = Gk2 × {Vr (k) -Vr (k-500)} Gk1 and Gk2 are coefficients. Also, Vr (k) is present, Vr (k-100) is 100 msec ago, and Vr (k-500) is 50
Each wheel speed is 0 msec before.

Then, from the acceleration VG and the wheel speed Vr calculated as described above, each friction coefficient μ on the left and right sides of the road surface is obtained by three-dimensional interpolation according to the following Table 1. When the slip control is not being performed, the friction coefficient μ is set to 3.0.

[0039]

[Table 1] [Setting of control target value] This control target value is the front wheel 1FL,
It is a target value as the slip amount of 1FR, and is calculated based on the wheel speed Vr and the friction coefficient μ. That is, the engine control target value SET is equal to the wheel speed Vr of the faster driven wheel of the left and right driven wheels 1RL and 1RR.
And a coefficient of friction μ, the value is reduced as the wheel speed Vr increases, and the value is reduced as the coefficient of friction μ decreases. A map set to a value higher than the engine control target value is used to calculate the brake control target value SBT.

[Slip Amount Calculation] The slip amount calculation is performed as follows. The wheel speed VFL of the left and right drive wheels 1FL, 1FR is subtracted from the wheel speed Vr of the left and right driven wheels 1RL, 1RR from the wheel speeds VFL, VFR to obtain the slip amount S of both wheels.
L and SR are obtained, the average slip amount SAv is calculated based on the slip amounts SL and SR, and the larger one of the slip amounts SL and SR is obtained as the maximum slip amount SHi. .. SHi is used in engine control, and SL and SR are used to independently control the braking force applied to the left and right drive wheels in brake control.

[Slip Judgment] When SHi becomes equal to or higher than the engine control target value SET, it is judged that engine control is necessary, and SL or SR is the brake control target value SBT.
When the above is reached, it is determined that brake control is required.

[Calculation of control amount] The engine control amount is obtained from a predetermined map based on the deviation of the average slip amount SAv from the control target value SET and the rate of change of this deviation over time. Further, the brake control amount is also the control target value S of the slip amounts SL and SR, similarly to the engine control amount.
It is calculated from a predetermined map based on the deviation from BT and the rate of change of this deviation.

[Output Control] Engine control is performed by adjusting the opening of the sub-throttle valve according to the engine control amount. The brake control is performed by outputting a control signal according to the brake control amount calculated for each drive wheel to the hydraulic pressure adjusting valves 15L and 15R (duty control).

[Slip Control Example] FIG. 3 shows an example of slip control. That is, up to time t ₁ ,
Since no large slip has occurred on the drive wheels, engine control is not performed, so the sub-throttle valve is fully open and the throttle opening Tn (combined opening of both main and sub throttle valves, The opening degree of the throttle valve having the smaller opening degree is the opening degree TH · M of the main throttle valve corresponding to the accelerator pedal depression amount.

[0045] In time point t _1, the slip amount of the drive wheel, a large slip incurred became engine control target value SET. In this time point t _1, the throttle opening is reduced at a stroke to a preset lower limit control value SM (feed-forward control). Then, once the SM is set, the opening degree of the sub-throttle valve is feedback-controlled so that the slip amount of the driving wheels becomes the engine control target value SET. At this time, the throttle opening Tn becomes the sub-throttle valve opening TH · S.

[0046] In t ₂ time is when the slip amount of the drive wheels becomes the brake control target value SBT above, both this time, the brake fluid pressure is supplied to the drive wheels, an engine control and brake control The slip control is started by. The brake fluid pressure is feedback-controlled so that the slip amount of the driving wheels becomes the brake control target value SBT.

[0047] In t ₃ time is when the slip amount of the drive wheel is less than the brake control target value SBT, thereby, the brake fluid pressure is gradually reduced, eventually the brake fluid pressure becomes zero. However, engine control is still continued.

In the embodiment, the conditions for ending the engine control are as follows:
It is assumed that the slip amount has converged to SET. The brake control is as follows.

[Brake Control Restriction] The brake control restricting means 53 includes an idle switch S5 and a failure detecting means 55.
Also, the operation of the brake control means of the control means 51 is prohibited based on each signal from the split road determination means 54.

First, the idle switch S5 will be described. It outputs an ON signal when the accelerator pedal 10 is released. The failure detection means 55 receives an acceleration signal (VG> 0) indicating that the vehicle is accelerating from the control means 51 and a signal from the idle switch S5, and while receiving the acceleration signal, an ON signal from the idle switch S5. When the state in which is input continues for a predetermined time, the failure of the idle switch S5 is determined. The split road determination means 54 receives the friction coefficient μ of the left and right portions of the road surface from the friction coefficient detection means, and determines that the road surface is a split road when the difference between the left and right μ is greater than or equal to a predetermined value.

Then, the brake control restricting means 53 is provided.
The above means gives an operation prohibition signal of the brake control means to the control means 51 when at least one of the following conditions is satisfied and the split road determination means 54 has not determined the split road.

The idle switch S5 is on. The failure detection means 55 detects the failure of the idle switch S5.

The flow of the brake control regulation is shown in FIG. Various data are input, and first the idle switch S
It is confirmed whether or not No. 5 is out of order, and if not, whether or not the idle switch S5 is turned on (steps P1 to P3). And the idle switch S
5 is faulty or idle switch S5
If is turned on, it is confirmed whether or not slip control is being performed (step P4). If it is under control, the brake control is restricted (prohibited) when the split road is not determined, and if the split road is determined, the brake control is continued (steps P5 and P6). Further, even when the control is not being performed, the brake control is restricted from being performed thereafter (steps P4 and P6).

Accordingly, not only when the release of the accelerator pedal 10 from being depressed is detected by the idle switch S5 but also when the idle switch S5 fails, the brake control by the brake control means is immediately prohibited and the drive wheels are driven. The application of the braking force of is released. Therefore, when the driver depresses the brake pedal 12, regardless of the state of the idle switch S5, the application of the braking force by the brake control means is always released, so that the operation of depressing the brake pedal is not restricted. The driver will not feel discomfort.

Further, in the booster 11, at the same time when the idle switch S5 is turned on, the switching valve 38 is demagnetized so that the first chamber 34 communicates with the second chamber 35.
The introduction of negative pressure to 5 is started. Therefore, it becomes possible to terminate the introduction of the negative pressure when the brake pedal 12 is stepped on, and to secure the negative pressure in the first chamber 34 to obtain the desired braking force. It becomes easier to secure power.

As described above, even if the brake control operation is restricted, the engine control operation is not restricted. That is, even if the idle switch S5 fails, the engine control is performed. Therefore, during acceleration of the vehicle, good acceleration can be ensured by the engine control.

On the other hand, when the split road is judged, there is no regulation of the brake control. Therefore, on the split road, even if the idle switch S5 fails during the brake control, the brake control is continued, which is advantageous in ensuring the behavior stability of the vehicle.

[Brief description of drawings]

 The drawings show embodiments of the invention.

FIG. 1 is an overall configuration diagram of a vehicle slip control device.

FIG. 2 is a sectional view of a brake booster.

FIG. 3 is a diagram showing an example of changes over time in a slip amount of a drive wheel in slip control.

FIG. 4 is a flow chart of regulation control of brake control.

[Explanation of symbols]

 1FL, 1FR Drive Wheel 2 Engine 7FL to 7FR Brake 8 Master Cylinder 9 Engine Output Adjusting Means 10 Accelerator Pedal (Accelerator Means) 12 Brake Pedal 32 Diaphragm 34 First Chamber 35 Second Chamber 38 Switching Valve 51 Control Means 53 Brake Control Restricting Means 54 split road determination means 55 failure detection means S5 idle switch (sensor)

Claims (4)

[Claims] 1. A slip control device for a vehicle, comprising: a brake control means for controlling a braking force applied to a drive wheel so that a slip amount of the drive wheel with respect to a road surface during acceleration of the vehicle reaches a target value. A sensor for detecting the release of the operation of the accelerator means of the engine, a failure detecting means for detecting the failure of the sensor, a detection of the operation release of the accelerator means by the sensor, and a detection of the failure of the sensor by the failure detecting means. A slip control device for a vehicle, comprising: a brake control restricting means for prohibiting the operation of the brake control means when at least one of the above is detected. 2. The engine control means for reducing the engine output so that the slip amount of the drive wheel with respect to the road surface reaches a target value without being restricted by the control by the brake control restricting means. The slip control device for a vehicle according to item 1. 3. The difference between the friction coefficient detecting means for detecting the friction coefficient of the left and right portions of the road surface on which each of the left and right driving wheels rolls and the friction coefficient of the left and right portions of the road surface detected by the friction coefficient detecting means are predetermined values. The slip control device for a vehicle according to claim 1, further comprising: a split road determination unit that determines that the road surface is a split road at the above time and prohibits the operation of the brake control restriction unit. 4. A negative pressure source, a first chamber into which the negative pressure of the negative pressure source is introduced, a second chamber into which the negative pressure of the first chamber and the atmosphere are switched and introduced, and the first chamber. A vacuum booster that includes a diaphragm for partitioning the chamber and the second chamber, and switches the introduction into the second chamber from negative pressure to the atmosphere by depressing the brake pedal, and assists the depressing force of the brake pedal through the diaphragm; And an introduction switching unit that introduces the atmosphere into the second chamber when the braking force is controlled and is controlled by the brake control unit, and introduces the negative pressure of the first chamber into the second chamber when the braking force is not controlled. The slip control device for a vehicle according to claim 1.