JP3076438B2 - Vehicle slip control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A slip control device for a vehicle detects a slip amount of a drive wheel in order to prevent the drive wheel from slipping due to an excessive drive torque and deteriorating the acceleration when the vehicle is accelerated. It is generally known to perform engine control for reducing the engine output and brake control for controlling the braking force of the drive wheels so that the slip amount becomes the target slip amount. Further, in the brake control, there is known a brake booster for assisting the depression force of a brake pedal to obtain a control brake force (see Japanese Patent Publication No. 3-5344).

That is, in the apparatus utilizing the vacuum booster, a negative pressure is introduced into each of a first chamber and a second chamber partitioned by a diaphragm, and when a brake pedal is depressed or brake control is performed. By introducing the atmosphere into the second chamber and obtaining a pressure difference between the two chambers, the depression force of the brake pedal is assisted through the diaphragm, or the braking force required for brake control is ensured. .
When the brake pedal is depressed or brake control is released, the negative pressure of the negative pressure source is introduced into the second chamber via the first chamber instead of the atmosphere.

[0004]

However, in the type using the above-mentioned vacuum booster, the time until the introduction of the negative pressure from the first chamber to the second chamber ends even after the brake control ends. Means that the negative pressure in the first chamber is temporarily reduced. Further, even if the pressure difference between the first chamber and the second chamber substantially disappears after the brake control ends (even if the introduction of the negative pressure ends), the consumption of the negative pressure in the brake control is large. Therefore, for example, when the negative pressure source is the negative pressure of the intake air of the engine, the negative pressure in the first chamber may still be insufficient. Therefore, even if the brake control is restarted in such a state and air is introduced into the second chamber, a pressure difference required for the brake control between the first chamber and the second chamber cannot be obtained. Brake control cannot be performed.

[0005] That is, an object of the present invention is to provide a slip control device utilizing the above-described vacuum booster for securing a braking force for the brake control, in which the brake control is started in a state where a required braking force cannot be obtained. It is to prevent that.

[0006]

SUMMARY OF THE INVENTION The present invention provides
In order to solve such a problem, the start of the brake control is allowed only when it is confirmed that the negative pressure necessary for the brake control is held in the first chamber.

In other words, a means for solving the above-mentioned problem is a vehicle having a brake control means for controlling a braking force applied to a drive wheel such that a slip amount of the drive wheel with respect to a road surface during acceleration of the vehicle becomes a target value. 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, A vacuum booster that includes a diaphragm that partitions the first chamber and the second chamber, and that switches the introduction into the second chamber from a negative pressure to the atmosphere by depressing a brake pedal and that assists the depressing force of the brake pedal through the diaphragm. Equipment and
Introduction switching means controlled by the brake control means to introduce air into the second chamber during brake control, and to introduce negative pressure in the first chamber into the second chamber during non-brake control; and negative pressure in the first chamber. A negative pressure information source for providing information on the size of the vehicle, and whether or not a negative pressure required for the brake control is held in the first chamber based on the information of the negative pressure information source in a non-brake control state. And a control start restricting means for prohibiting the control start of the brake control means when the required negative pressure is not held.

In this means, it is determined from the information on the magnitude of the negative pressure in the first chamber obtained by the negative pressure information source that the negative pressure required for brake control is not held in the first chamber. At times, the start of the brake control is prohibited. Therefore, the atmosphere is not introduced into the second chamber when the negative pressure in the first chamber is insufficient, and a sufficient braking force is guaranteed without obtaining a sufficient pressure difference between the two chambers. It is possible to prevent the brake control from being started with no state.

When it is determined that the required negative pressure is held in the first chamber, the brake control can be started. Therefore, when the brake control is started, the brake control must be started.
The brake force required for the control can be obtained, and the desired brake control can be performed.

A vacuum pump can be used as the negative pressure source, but the negative pressure of the intake air of the engine is preferable because such a vacuum pump is not required. When this intake negative pressure is used as a negative pressure source, a negative pressure sensor that directly detects the magnitude of the negative pressure in the first chamber can be used as the negative pressure information source, but without using such a sensor, For example, the accelerator means of the engine or a rotation sensor for detecting the engine speed can be used as a negative pressure information source.

That is, in the case of the accelerator means of the engine, the throttle valve is closed by releasing the operation thereof, and a large intake negative pressure is generated. Therefore, the control start restricting means may determine that the negative pressure required for the brake control is held in the first chamber when detecting the release state of the accelerator means in the non-brake control state. it can. In this case, it is preferable to make the determination when the operation release state of the accelerator means has continued for a predetermined time or more, in order to make the determination reliable.

In the case of the above-mentioned rotation sensor, the higher the engine speed, the larger the intake air amount and the higher the intake negative pressure. Therefore, in the control start restricting means, the negative pressure required for the brake control is held in the first chamber when the engine speed detected by the rotation sensor becomes equal to or higher than the predetermined value in the non-brake control state. Can be determined.

Further, a friction coefficient detecting means for detecting a friction coefficient on the right and left portions of the road on which each of the left and right driving wheels rolls, and a difference between the friction coefficients on the right and left portions of the road detected by the friction coefficient detecting means is a predetermined value. In this case, it is also preferable to provide a split road determining means for determining that the road is a split road and prohibiting the operation of the control start restricting means.

In this case, on the split road, the operation of the brake control means has priority over the operation of the control start restriction means. That is, on the split road, even if the required negative pressure is not held in the first chamber, the brake control is started, which is advantageous in terms of ensuring the stability of the behavior of the vehicle.

[0015]

Therefore, according to the present invention, in a slip control device utilizing a vacuum booster for securing a braking force for brake control, the magnitude of the negative pressure in the first chamber of the vacuum booster is improved. Control start restriction for judging whether or not the negative pressure required for the brake control is held in the first chamber based on the information on the first chamber, and prohibiting the start of the brake control when the required negative pressure is not held. Because we have the means,
It is possible to prevent the brake control from being started in a state where a sufficient boosting force cannot be secured by the vacuum booster. That is, when the brake control is started, the brake force required for the control must be ensured. Thus, the desired brake control can be performed.

Further, the negative pressure source of the vacuum booster is the negative pressure of the intake air of the engine, and the negative pressure necessary for the brake control is supplied to the first chamber when the release state of the accelerator means of the engine is detected. According to the determination that the negative pressure is held, or the determination that the negative pressure required for the brake control is held in the first chamber when the engine speed exceeds a predetermined value, a special negative pressure is applied. The required brake control can be started by obtaining necessary information without using a pressure sensor.

When the difference between the friction coefficients of the right and left portions of the road detected by the friction coefficient detecting means is equal to or larger than a predetermined value, the road is determined to be a split road and the operation of the control starting means is prohibited. According to the vehicle equipped with the means, the brake control is guaranteed on the split road, which is advantageous in terms of securing the behavior stability of the vehicle.

[0018]

1 is a front left wheel, 1FR is a front right wheel, 1RL is a rear left wheel, and 1RR is a rear right wheel. An engine 2 is mounted horizontally on the front of the vehicle body. The torque generated by the engine 2 is transmitted to a clutch 3, a transmission 4, and a differential gear 5, and then transmitted to a left front wheel 1FL via a left drive shaft 6L. And via the right drive shaft 6R to the right front wheel 1FR. As described above, the vehicle has the front wheels 1F
L, 1FR are drive wheels, and rear wheels 1RL, 1RR are front wheel drive vehicles that are driven wheels.

Brake 7FL to 7R mounted on each wheel
R is a hydraulic disc brake.
Also, a master cylinder 8 as a brake fluid pressure generation source
Is a tandem type having two discharge ports 8a and 8b. A brake pipe 13 extending from one discharge port 8a of the master cylinder 8 is branched into two on the way.
The branch pipe 13F is connected to the left front wheel brake 7FL (a wheel cylinder mounted in 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
F and 14F are provided with an electromagnetic hydraulic pressure control valve 15L or 1F.
5R is connected, and an electromagnetic on-off valve 16L or 16R is connected to the rear wheel branch pipes 13R and 14R. The hydraulic pressure adjusting valves 15L and 15R are provided with a brake 7FL,
The brake fluid pressure from the master cylinder 8 to the 7FR and the brake fluid pressure of the brakes 7FL and 7FR are
The mode is switched between release to the reservoir tanks 22L and 22R via 1L and 21R. The brake fluid in the reservoir tank 21L is returned to the pipe 13 by a pump 23L via a pipe 25L to which a check valve 24L is connected. Similarly, the brake fluid in the reservoir tank 22R is
By R, it is returned to the pipe 14 via the pipe 25R to which the check valve 24R is connected.

The depression force on the brake pedal 12 is
The power is transmitted to the master cylinder 8 via a booster, that is, a brake booster 11. This booster 11 is basically the same as a known vacuum booster. However, in the case of slip control, as 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 the inside of the case 31 is divided into a first chamber 34 and a second chamber 34 by a diaphragm 32 and a valve body 33 fixed thereto. 35. The first chamber 34 always has the negative pressure of the negative pressure source (engine 2
When the brake pedal is not depressed, the second chamber 35 is communicated with the first chamber 34, 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 to obtain a boosting action.

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

First, the valve body 33 has a power piston 41 fixed to the diaphragm 32. In a recess 41a formed in the power piston 41, a reaction disk 42 and a base end of an output shaft 43 are formed. Mated. This output shaft 43 serves as an input shaft of the master cylinder 8. A valve plunger 45 is mounted in the valve body 33 at the tip of the input shaft 44 connected to the brake pedal 12. Behind the valve plunger 45, a vacuum valve 46 is provided.

A pressure introduction passage 50 is provided in the power piston 41.
The pressure introducing passage 50 is always in communication with a space X formed around the valve plunger 45. This space X is always in communication with the second chamber 35. A valve seat 47 on which the vacuum valve 46 is detached and seated is formed at an opening end of the pressure introducing passage 50 on the space X side. Further, the vacuum valve 46 includes a valve plunger 45.
The seat is also detached from and seated on a valve seat 45a formed at the rear end.

In the above configuration, it is assumed that a negative pressure is 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. I have. Therefore, the pressure introduction passage 5
The negative pressure from 0 is introduced into the second chamber 35 via the space X, and no boosting action is performed.

When the brake pedal 12 is depressed,
The input shaft 44 and thus the valve plunger 45 are moved forward (to the left 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 introduction passage 50 are
To the vacuum valve 46 and the valve seat 45
a are separated. When the vacuum valve 46 and the valve seat 45a are separated from each other, the atmospheric pressure from behind 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 via the reaction disk 42 to the valve plunger 45 and thus to the brake pedal 12.
When the depressing operation force of the brake pedal 12 is released, the state is returned to the state of FIG. 2 by the return spring 36 (see FIG. 1), and the vehicle is prepared for the next boosting action.

Although the parts described above are the same as those of the known vacuum booster, in the present embodiment, the negative pressure of the first chamber 34 is introduced into the pressure introduction passage 50 for slip control. The state is switched to a state in which atmospheric pressure is introduced. That is, the first chamber 34 and the pressure introduction 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). The switching valve 38 is connected to the pressure introducing passage 50 during demagnetization.
Is communicated with the first chamber 34, and the atmospheric pressure is introduced into the pressure introducing passage 50 at the time of excitation. When the switching valve 38 is excited and the atmospheric pressure is introduced into the pressure introducing passage 50, the space X, and thus the second chamber 35, becomes the atmospheric pressure even if the brake pedal 12 is not depressed. By performing the boosting operation, the brake fluid pressure is generated in the master cylinder 8.

Next, the control system will be described. The control system is
It is configured using a microcomputer, and FIG.
In the figure, reference numeral 51 denotes control means for performing engine control and brake control.
Signals from the sensors S1 to S4 for detecting the rotation speeds of L to 1RR and signals from the brake control start restricting means 53 are input.

The control means 51 includes a friction coefficient detecting means for detecting a friction coefficient of the road surface, a control target value setting means, a slip amount detecting means, a slip determining means, a control amount calculating means, and an engine output and brake control means. The control means 51 includes an output means, an engine output adjusting means 9 for engine control, hydraulic pressure adjusting valves 15L and 15R for brake control, and opening / closing valves 16L and 1
Control signals are output to 6R and the switching valve 38. The engine output adjusting means 9 is a sub-throttle valve (not shown) provided in the intake passage separately from the main throttle valve linked to the accelerator pedal (accelerator means of the engine 2) 10.
Is driven to adjust the engine output.

The control start restricting means 53 receives signals from the idle switch S5 for detecting the release of the operation of the accelerator pedal and signals from the split road determining means 54.

Hereinafter, a specific description will be given. [Detection of Road Surface Friction Coefficient] The friction coefficient detection means detects the friction coefficient of the right and left road surfaces 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
It is performed based on.

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

− (1) Equation−VG = Gk1 × ｛Vr (k) −Vr (k−100)｝ − (2) Equation−VG = Gk2 × ｛Vr (k) −Vr (k−500)｝ Gk1 and Gk2 are coefficients. Vr (k) is at the present time, Vr (k-100) is 100 msec before, and Vr (k-500) is 50 msec.
These are the wheel speeds before 0 msec.

Then, from the acceleration VG and the wheel speed Vr calculated as described above, the respective friction coefficients μ of the right and left portions of the road surface are 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.

[0036]

[Table 1] [Setting of control target value] This control target value is determined by the front wheels 1FL,
The value is a target value as the 1FR slip amount and is also a control start threshold value, which is calculated based on the wheel speed Vr and the friction coefficient μ. That is, the engine control target value SET is determined based on the wheel speed Vr and the friction coefficient μ of the faster one of the left and right driven wheels 1RL and 1RR so that the value decreases as the wheel speed Vr increases. In addition, the calculation is performed from a map set such that the value decreases as the friction coefficient μ decreases. In calculating the brake control target value SBT, a map set to a value higher than the engine control target value is used.

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

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

[Control Amount Calculation] 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 with time. Also, the brake control amount is similar to the engine control amount, and the control target value S of the slip amounts SL and SR is
It is calculated from a predetermined map based on the deviation from the BT and the rate of change of this deviation.

[Output Control] The 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 corresponding to the brake control amount calculated for each drive wheel to the hydraulic pressure adjusting valves 15L and 15R (duty control).

[Example of Slip Control] FIG. 3 shows an example of slip control. In other words, until t ₁ ,
Since no large slip has occurred in the drive wheels, no engine control is performed, and therefore the sub-throttle valve is fully opened and the throttle opening Tn (the combined opening of the main and sub throttle valves, (Corresponding to the opening of the smaller throttle valve) is the opening TH · M of the main throttle valve corresponding to the accelerator pedal depression amount.

[0042] 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 SM is set, the opening degree of the sub-throttle valve is feedback-controlled so that the slip amount of the drive wheel becomes the engine control target value SET. At this time, the throttle opening Tn becomes the subthrottle valve opening TH · S.

[0043] 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 Starts the slip control. The brake fluid pressure is feedback-controlled so that the slip amount of the drive wheel becomes equal to the brake control target value SBT.

[0044] In t ₃ time, the slip amount of the drive wheels is at when it becomes 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 condition for terminating the engine control is a time when the slip amount converges on the SET.

[Restriction of Brake Control] The control start restricting means 53 is based on the signals from the idle switch S5 and the split road determining means 54, and controls the control means 51.
The start of operation of the brake control means is regulated.

First, the idle switch S5 will output an ON signal when the depression of the accelerator pedal 10 is released. Also,
The split road determination unit 54 receives the friction coefficient μ of the right and left portions of the road surface from the friction coefficient detection unit, and determines that the road surface is a split road when the difference between the left and right μ is equal to or greater than a predetermined value.

Then, the control start restricting means 53
If no ON signal is received from the idle switch S5 in the non-brake control state, it is determined that the negative pressure required for the brake control is not held in the first chamber 34 of the vacuum booster, and the brake control is performed. The operation start prohibition signal of the means is given to the control means 51. However, the control start restricting means 53 cancels the restriction when the split road determining means 54 determines the split road.

Specifically, the flow is as shown in FIG. In the same flow, the flag F1 = 1 means that the brake control start is prohibited, and F1 = 0 means that the brake control is released. Also, F2 = 1 means that there is a split road determination, and F2 = 0 means that this determination is canceled.

First, various data are input and the flag F1
Is determined (steps P1 and P2). When F1 is not 1 (brake control is possible), the slip amounts SL, S
When R exceeds the brake control target value SBT and the brake control is started, flag processing of F1 ← 1 and F2 ← 0 is performed (steps P3 to P6). The flag processing of F1 ← 1 is for preventing the brake control from being restarted after the brake control is completed even if the required negative pressure is not secured, and the flag processing of F2 ← 0 is performed after the start of the control. Is unnecessary.

After the above brake control is started, F1 =
Therefore, the determination in step P2 is Yes, and it is determined whether the brake control has been completed (step P2).
7). When the brake control is completed and the accelerator switch S5 is turned on, a flag process of F1 ← 0 is performed, and
This allows the brake control to be restarted (steps P8 and P9).

On the other hand, even if the accelerator switch S5 is not turned on, if the split road is determined, the flag processing of F2 ← 1 and F1 ← 0 is performed, and the brake control can be resumed (step S5). P10, P1
1, P9). In this state, if the slip amounts SL and SR exceed the control target value SBT, step P is performed as in the previous case.
The process proceeds in the order of 3 → P4 → P5 → P6. Also, the slip amount SL,
If SR does not exceed the control target value SBT, F2 = 1, so the determination in step P12 is Yes, and it is again confirmed whether or not the vehicle is on a slip road (step P12 → P10). And on a split road,
If the state of F1 = 0 (brake control is possible) is maintained and the determination of the split road is eliminated, F1 ← 1 and F2 ←
The flag processing of 0 is performed. That is, in this case, since the accelerator switch S5 has not been turned on yet,
The start of the brake control is restricted.

Therefore, even if the brake control ends, unless the accelerator switch S5 is turned on, the brake control is not basically started. That is, when the brake control ends, the switching valve 38 of the booster 11 operates to introduce a negative pressure from the first chamber 34 to the second chamber 35, but until the end of the introduction, the negative pressure of the first chamber 34 is reduced. If the pressure is temporarily reduced and the introduction of the negative pressure is substantially terminated, but the intake negative pressure of the engine is not sufficient, the negative pressure in the first chamber 34 becomes insufficient. Therefore, in such a state, the start of the brake control is not allowed, and the brake control in a state where the braking force is insufficient is prevented. Of course, as described above, even if the brake control is restricted, the engine control can be executed, and therefore, there is no problem of a decrease in the acceleration due to an excessive increase in the slip amount.

When the accelerator switch S5 is turned on, a large intake negative pressure is generated in the engine, and the negative pressure in the first chamber 34 rapidly increases. Only in such a state, the flag F1 becomes 0 and the start of the brake control is permitted. Therefore, the required brake force can be obtained and the desired brake control can be executed. Further, as described above, since it is determined whether the start of the brake control should be permitted by obtaining the negative pressure information of the first chamber 34,
Even if a vacuum pressure is not used and the negative intake pressure of the engine is used as a negative pressure source, the intended brake control is guaranteed.
Further, since the accelerator switch S5 is used as a negative pressure information source, it is advantageous in terms of cost that a special negative pressure sensor is not required.

Even if the accelerator switch S5 is not turned on, if a split road is determined, F
Since 1 = 0 and the start of brake control is allowed,
When the slip amount increases, necessary brake control can be performed. That is, on a split road, it is more important to ensure the stability of the behavior of the vehicle.

The rotation sensor 55 and the negative pressure sensor 56 shown in FIG. 1 can be used as the negative pressure information source. The rotation sensor 55 detects the engine speed. In this case, the start of the brake control is allowed when the engine speed reaches a set value or more.
Further, the negative pressure sensor 56 directly detects the negative pressure of the first chamber 34, and allows the start of the brake control when a negative pressure equal to or more than the set value is detected.

[Brief description of the drawings]

 The drawings show an embodiment of the present 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 a temporal change of a slip amount of a drive wheel or the like in slip control.

FIG. 4 is a flowchart of a regulation for starting 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 Control start restricting means 54 split road determination means 55 rotation sensor S5 idle switch

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-180551 (JP, A) JP-A-3-54057 (JP, A) JP-A-1-109158 (JP, A) JP-A-3-3 104762 (JP, A) JP-A-3-21564 (JP, A) JP-A-61-2270 (JP, U) JP-B-3-5344 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60T 8/58 B60T 8/44

Claims (4)

(57) [Claims] 1. A slip control device for a vehicle, comprising: brake control means for controlling a braking force applied to a drive wheel such that a slip amount of the drive wheel with respect to a road surface during acceleration of the vehicle becomes a target value. 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, the first chamber and the second chamber A vacuum booster that switches the introduction into the second chamber from the negative pressure to the atmosphere by depressing a brake pedal and assists the depressing force of the brake pedal via the diaphragm; and the brake control means. Introduced switching means for introducing the atmosphere into the second chamber during the controlled brake control and introducing the negative pressure in the first chamber into the second chamber during the non-brake control, and information on the magnitude of the negative pressure in the first chamber. Provide negative pressure information In the non-brake control state, it is determined whether or not a negative pressure required for the brake control is held in the first chamber based on the information of the negative pressure information source, and the required negative pressure is not held And a control start restricting means for prohibiting control start of the brake control means. 2. The negative pressure source is a negative pressure of intake air of an engine,
The negative pressure information source is an accelerator unit of the engine, and the control start restricting unit holds a negative pressure required for the brake control in the first chamber when detecting the operation release state of the accelerator unit. The slip control device for a vehicle according to claim 1, wherein: 3. The negative pressure source is a negative pressure of intake air of an engine.
The negative pressure information source is a rotation sensor for detecting an engine speed, and the control start restricting means is configured to apply the brake to the first chamber when the engine speed detected by the rotation sensor becomes a predetermined value or more. The vehicle slip control device according to claim 1, wherein it is determined that a negative pressure required for control is held. 4. A friction coefficient detecting means for detecting a friction coefficient on the right and left portions of the road on which the left and right driving wheels roll, and a difference between the friction coefficients on the right and left portions of the road detected by the friction coefficient detecting means is a predetermined value. 2. The vehicle slip control device according to claim 1, further comprising: a split road determination unit that determines that the vehicle is on a split road and prohibits the operation of the control start restriction unit.