JP2919029B2 - Anti-skid brake system for vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an anti-skid brake device for a vehicle.

(Prior Art) An anti-skid brake device is basically designed so that a wheel speed is reduced with a predetermined deceleration (control threshold) as a target or a wheel slip ratio is set to a target slip ratio (control threshold). By controlling the increase / decrease of the braking pressure applied to the wheels (hereinafter simply referred to as ABS control as necessary), it is possible to prevent the locking or skid state of the wheels during braking and to maintain the directional stability. The vehicle is stopped at a short braking distance without losing the vehicle.

There are various proposals for the control of the braking pressure. For example, Japanese Patent Application Laid-Open No. 62-253560 discloses that the target slip ratio is changed according to the rotation angle of the steering wheel to achieve both the braking effect and the controllability. There is a disclosure about a technology for achieving the above. That is, when the steering angle is large, the steering pressure is improved by controlling the braking pressure with a target of a low slip ratio, and when the steering angle is small, the braking pressure is targeted with a high slip ratio. By performing the above control, the braking effect is enhanced.

(Problems to be Solved by the Invention) By the way, in driving a vehicle, braking may be applied to the wheels in a state where the driver temporarily panics. For example, when the vehicle suddenly jumps from the side of the road to the front of the vehicle while the vehicle is running, in such a case, the driver instinctively turns the steering wheel to the right and left while stepping on the brake pedal strongly to avoid danger. In some cases, the operation of cutting quickly is performed.

In such a situation, when the anti-skid brake device operates in the same manner as during normal braking, a predetermined lateral drag (reaction force from the road surface) is obtained in consideration of the fact that the device itself performs turning motion even during braking. The vehicle is not necessarily provided with the highest possible braking effect because the braking pressure is controlled to increase or decrease as described above.

That is, an object of the present invention is to make it possible to quickly stop a vehicle at a short braking distance while utilizing the characteristics of the anti-skid brake device even in the above-mentioned panic state.

(Means for Solving the Problems) In order to solve such a problem, the present invention detects a steering speed by a driver's steering operation, and changes a threshold value of the braking pressure control according to the steering speed. It is to be.

That is, specifically, a wheel speed detecting means for detecting the rotational speed of the wheel, a braking pressure adjusting means for adjusting the braking pressure of the wheel, and a predetermined control threshold value based on the wheel speed detected by the wheel speed detecting means. An anti-skid brake device for a vehicle, comprising: control means for controlling the braking pressure adjusting means so as to increase or decrease the braking pressure according to the following. based on the steering speed detected by the means and a control threshold value changing means for changing the control threshold, the control threshold changing means, the control threshold in the above steering speed predetermined speed value a ₀ or more It is characterized in that it is changed in a direction to increase the braking efficiency of the wheel at a certain time.

In this case, it is possible to change the direction in which the braking efficiency of the wheel with the control threshold is lowered when the steering speed is a predetermined low speed value A ₁ below.

When the steering amount is equal to or less than a predetermined value, when the friction coefficient of the road surface is equal to or more than a predetermined value, when the vehicle speed is equal to or less than a predetermined value, or when the brake pedal depressing speed is equal to or less than a predetermined value, Even when the steering speed is high, it is possible to prohibit the control threshold value changing means from changing the control threshold value.

(Operation) The anti-skid brake device includes means for changing the threshold value for the braking pressure control based on the turning speed. Therefore, the vehicle is stopped at a shorter braking distance than usual because the braking pressure is applied to the vehicle, that is, the direction in which the braking efficiency of the wheels is increased.

In this case, since the wheels tend to be locked, it is not possible to sufficiently secure the lateral drag required for turning. However, a situation in which the steering speed during braking is high is a situation in which the driver turns the steering wheel suddenly while stepping on the brake pedal to avoid danger, for example, in a panic situation. In general, turning the vehicle is not very useful for avoiding danger. Therefore, even if the turning performance is somewhat sacrificed, the vehicle is stopped as quickly as possible with a sufficient braking force.

Further, if the steering threshold is changed to a direction in which the braking efficiency of the wheel is lower than the normal control when the steering speed is attacked, that is, in a direction in which the lock becomes shallow, the control threshold is applied to the wheel during gentle steering. The lateral resistance required for turning can be obtained appropriately, and the stability or steering performance of turning can be improved.

Also, when changing the control threshold value in the lock-like direction when the steering speed is high as described above, whether or not to make the above change is determined based on the steering amount, the road surface friction coefficient, the vehicle speed, or the brake pedal depression speed. If the driver really panics, or if it is actually difficult to avoid the danger by turning, it is possible to avoid the danger by controlling the lock feeling become.

Conversely, when the steering amount is equal to or less than a predetermined value or when the brake pedal depressing speed is slow, the steering amount is determined by the driver's normal intention, and as a result of the brake pedal being depressed. Therefore, since the driver is not panicked, it is possible to avoid danger by steering.

Further, even when the coefficient of friction of the road surface is equal to or higher than a predetermined value or when the vehicle speed is low and equal to or lower than the predetermined value, danger can be avoided by steering.

(Effect of the Invention) Therefore, according to the present invention, the antiskid brake apparatus for a vehicle, the threshold for the control brake pressure when said transfer steering speed based on the steering speed is a predetermined speed value A ₀ or more Is changed in the direction in which the braking efficiency of the wheels is increased, so that when the steering is fast, for example, when the driver is in a panic state, the braking pressure is controlled so that the vehicle tends to be locked and the braking performance is improved. As a result, control according to the situation where the driver or the vehicle is placed can be performed.

Further, when the control threshold value is changed, if it is determined whether or not the change should be made based on the steering amount, the friction coefficient of the road surface, the vehicle speed, or the depressing speed of the brake pedal, the driver or the vehicle is placed. It becomes possible to grasp and control the situation in a more practical manner.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

 FIG. 1 shows the overall configuration of the embodiment.

That is, the anti-skid brake device of the vehicle
Control means 3 for controlling the increase and decrease of the braking pressure of the wheels by means of the braking pressure adjusting means 2 according to a predetermined control threshold value based on the wheel speed detected by the wheel speed detecting means 1; and control for changing the control threshold value based on the steering speed It comprises a threshold changing means 5 and a control threshold change prohibiting means 6 for prohibiting a change of the control threshold. The prohibition of changing the control threshold value is based on the steering amount, road surface friction coefficient,
This is performed based on the vehicle speed and the stepping speed of the brake pedal.

Specifically, as shown in FIG. 2, the vehicle according to this embodiment has left and right front wheels 11, 12 as driven wheels, left and right rear wheels 13, 14 as driving wheels, and Output torque from automatic transmission 16 to propeller shaft 17, differential device 18
And, it is configured to be transmitted to left and right rear wheels 13 and 14 via left and right drive shafts 19 and 20.

Each of the wheels 11 to 14 has a brake device including disks 21 a to 24 a that rotate integrally with the wheels and calipers 21 b to 24 b that brake the rotation of the disks 21 a to 24 a by receiving a supply of braking pressure. 21 to 24 are provided.

A brake control system for operating the brake devices 21 to 24 includes a booster 27 that increases the depression force of a brake pedal 26 by a driver, and a braking pressure according to the force increased by the booster 27. And a master cylinder 28 for generating. The front wheel braking pressure supply line 29 extending from the master cylinder 28 branches into a left front wheel braking pressure supply line 29a and a right front wheel braking pressure supply line 29b, and the calipers 21a and 22b of each of the brake devices 21 and 22. It is connected.
The left front wheel braking pressure supply line 29a has an electromagnetic on-off valve 3
0a and an electromagnetic relief valve 30b, and a second valve unit 31 comprising an electromagnetic on-off valve 31a and an electromagnetic relief valve 31b is provided on the right front wheel braking pressure supply line 29b. Is provided.

A third valve unit 33 including an electromagnetic on-off valve 33a and an electromagnetic relief valve 33b is provided on the rear wheel braking pressure supply line 32 extending from the master cylinder 28. The rear wheel braking pressure supply line 32 branches into a left rear wheel braking pressure supply line 32a and a right rear wheel braking pressure supply line 32b downstream of the third valve unit 33. 23 and 24 are connected to calipers 23a and 24b.

That is, in the present embodiment, the first channel for adjusting the braking pressure of the brake device 21 of the left front wheel 11 by the operation of the first valve unit 30 and the brake device 22 of the right front wheel 12 by the operation of the second valve unit 31 A second channel for adjusting the braking pressure of the left and right rear wheels 13, 14 by operating the third valve unit 33, and a third channel for adjusting the braking pressure of the braking devices 23, 24 of the left and right rear wheels 13, 14. They are controlled independently of each other. The first to third valve units 30, 31, 33 constitute the braking pressure adjusting means 3.

The control unit 34 for controlling the first to third channels includes a brake signal from a brake sensor 35 for detecting whether or not the brake pedal 26 is depressed and a stepping speed of the brake pedal 26, and for each of the wheels 11 to 14. Wheel speed sensors 37 to 37 as wheel speed detecting means 1 for detecting the rotational speed of the vehicle.
The wheel speed signal from the steering wheel 40 and the steering angle signal from the steering angle sensor 4 are input, and the ABS control is performed in parallel for each channel.

That is, the control unit 34
Control means 3 for controlling the increase and decrease of the braking pressure of each of the wheels 11 to 14 by the valve units 30, 31, 33 in accordance with a predetermined control threshold based on the wheel speeds of 〜14, control threshold change means 5, and control threshold change Prohibiting means 6, wherein the opening / closing valves 30 a, 31 a, 33 a and the relief valve 3 of the first to third valve units 30, 31, 33 are provided.
0b, 31b, and 33b are controlled to open and close by duty control. The brake oil discharged from the relief valves 30b, 31b, 33b is as follows. It is returned to the reservoir tank 28a of the master cylinder 28 by a drain line (not shown).

Hereinafter, the control unit 34 will be specifically described.

The control means 3 includes a pseudo vehicle speed setting unit and a control threshold setting unit. Phase 0 (ABS non-control state) and phase I (A
Select a phase from the braking pressure reduction state during BS control), phase II (holding state after pressure reduction), phase III (rapid pressure increase state after pressure reduction holding), and phase IV (slow pressure increase state after sudden pressure increase). The brake pressure control signal corresponding to each phase is output to the first to third valve units 30, 31, and 33.

The pseudo vehicle speed Vr is set as a vehicle speed for convenience based on the wheel speed because the vehicle speed when the wheels 11 to 14 are slipping cannot be accurately detected. While the maximum wheel speed of 14 is set to the pseudo vehicle speed Vr, the speed change amount is changed from 1.2 G 係数 Δt at the high friction coefficient to 0.3 G ・
It is set up to Δt and corrected as follows. In addition,
Δt is a sampling period of the control unit 34 (for example, 7 ms).

Vr ← Vr− (1.2 G · Δt to 0.3 G · Δt) The control threshold is set independently for each channel. In this example, the control threshold is set to the phase 0 (ABS non-control). 1) a first wheel deceleration threshold G1 for determining the transition from phase I to decompression, and a second wheel deceleration threshold for determining the transition from phase I to phase II (hold).
G2, a first slip ratio threshold value S1 for determining a transition from phase II to phase III (sudden pressure increase), and a wheel acceleration threshold value G3 for determining a transition from phase III to phase IV (slow pressure increase)
And a second slip ratio threshold S2 for determining transition from phase IV to phase I. The above control threshold is the pseudo vehicle speed.
It is set appropriately according to Vr and the friction coefficient of the road surface.

Regarding the wheel speeds of the rear wheels 13, 14, the smaller one of the two wheel speeds is selected as the rear wheel speed. Also,
The slip ratio is calculated according to the following equation.

Slip ratio = (1−wheel speed ÷ pseudo vehicle speed) × 100 In this case, the setting of the control threshold value in the normal ABS control is performed by setting the lateral drag coefficient μL of the wheel to the road surface excessively as shown in FIG. It is set so that the coefficient of friction μ between the road surface and the wheels can be increased without lowering, that is, a characteristic in the range of Ss is obtained. In other words, a high friction coefficient μ means high braking efficiency, and a high transverse stress coefficient μL means good stability or steering performance in cornering,
As can be seen from FIG. 3, it is difficult to achieve a balance between the braking efficiency and the turning performance. In the normal ABS control, a control threshold value is set so that the two are compatible as much as possible.

The deceleration and acceleration of the wheel are obtained by dividing the difference between the previous value and the current value of the wheel speed by the sampling period Δt, and converting the result to a gravitational acceleration.

When detecting the friction coefficient of the road surface, when the ABS is not controlled, it is determined uniformly as a high friction road surface, and after entering the ABS control, the friction coefficient of the road surface is detected based on the wheel deceleration and the wheel acceleration It is. That is, when the wheel deceleration is large and the wheel acceleration is small, it is determined that the road surface is low friction. When the wheel deceleration is small and the wheel acceleration is large, it is determined that the road surface is high friction.

Therefore, the control means 3 normally controls the increase or decrease of the braking pressure as shown in FIG.

That is, when the brake pedal 26 is depressed from the constant speed running state, the braking pressure generated in the master cylinder 28 increases, and the wheel speed decreases accordingly.

When the wheel deceleration becomes larger than the first wheel deceleration threshold value G1, the process proceeds to the ABS control, phase I is selected, and the braking pressure is reduced according to a predetermined pressure reduction mode.

When the wheel deceleration becomes smaller than the second wheel deceleration threshold value G2, phase II is selected and the braking pressure is maintained in a reduced pressure state.

If the slip ratio decreases with the above-described pressure reduction and exceeds the first slip ratio threshold S1, Phase III is selected,
A sudden increase in the braking pressure takes place.

When the wheel acceleration decreases due to the rapid pressure increase and becomes equal to or less than the wheel acceleration threshold value G3, the phase IV is selected, and the braking pressure is gradually increased.

When the slip rate exceeds the second slip rate threshold value S2 due to the above-described slow pressure increase, phase I is selected.

As described above, for each of the first to third channels,
By controlling the increase and decrease of the braking pressure independently of each other, the occurrence of the lock or skid state of each wheel is prevented, and the vehicle is stopped at a short braking distance without losing directional stability.

 Next, the control threshold value changing means 5 will be described.

Control threshold changing means 5 is for changing the control threshold according to the steering speed obtained by the steering angle sensor 4, the braking efficiency of the wheel control threshold when the predetermined high speed value A ₀ or more change in becomes higher (locked deep) direction, and changes the control thresholds braking efficiency is low (locked shallow) direction of the wheel when the predetermined low speed value a ₁ below.

In this case, A ₀ > A ₁ . That is, the A ₀ or more steering speed, for example, from the road transverse to the vehicle is running if there is a sudden jump out to the front of the vehicle, the driver temporarily panicked state, while pressing strongly the brake pedal, It is the steering speed when the steering wheel is turned instinctively to the right or left instinctively. Then, the control threshold value is changed so that the slip ratio threshold value is increased and the gradient of the pseudo vehicle speed Vr is increased to the negative side.

Specifically, when information of the steering speed A ₀ or more is obtained,
The first wheel deceleration threshold G1 for determining transition from phase 0 (when ABS is not controlled) to phase I (decompression) and the deceleration threshold G2 for determining transition from phase I to phase II (hold) are high. The first slip ratio threshold value S for determining the transition from phase II (reducing pressure) to phase III (rapid pressure increase).
2 and the second for determining the transition from Phase IV to Phase I
The slip ratio threshold value S2 is high, that is, it becomes deeper when viewed from the pseudo vehicle speed Vr.
A predetermined correction is made to each of the threshold values so as to lower the wheel acceleration threshold value G3 for determining transition to (slow pressure increase).

The change of the control threshold will be described with reference to FIG. 3. If the change is performed, the slip ratio Sμ at which the highest friction coefficient μ (maximum braking efficiency) is obtained even at the expense of the lateral drag coefficient μL,
Or a higher slip ratio (deeper lock).

Further, the A ₁ following the turning speed, a steering speed when the driver performs the turning on the basis of its clear intention. Then, for the control threshold, the slip ratio threshold is lowered,
In addition, the inclination of the pseudo vehicle speed Vr is changed to be small. Specifically, when the steering speed A ₁ The following information has been obtained, the first slip ratio threshold S1, the second slip ratio threshold
S2, the deceleration threshold G1 and the acceleration threshold G2 is intended to correct changes in the opposite manner to the case of the A _0, in terms of the FIG. 3,
Even if the friction coefficient μ is sacrificed, the control threshold value is changed with a target near the slip ratio SμL at which a high transverse stress coefficient μL can be obtained.

FIG. 5 is a flowchart showing a change control of the above control threshold, the brake signal, the wheel speed signals, and inputs the steering speed signal, when the steering speed dθH / dt is greater than the predetermined value A _0, the control ABS control is performed by changing the threshold value in the lock deepening direction (steps S1 to S3). The turning speed dθH / dt is a predetermined value A ₀
When less than, it determines whether or not a predetermined value A ₁ below, a predetermined value A ₁
Performs ABS control by changing the control threshold in the lock shallow in the following cases, so that for normal ABS control without changing the control threshold when exceeding the predetermined value A ₁ (step S4 to S6).

Therefore, for example, there is a sudden jump from the side of the road to the front of the vehicle while the vehicle is running, and the driver temporarily panics, and while pressing the brake pedal strongly, instinctively turn the steering wheel right and left quickly. When the vehicle is turned off, the ABS control is performed deeper than usual to increase the braking efficiency of the wheels, and the vehicle can be stopped at a short braking distance. On the other hand, if the driver can steer slowly, the AB
By performing the S control, it is possible to appropriately obtain the lateral resistance required for the turning traveling on the wheels, and it is possible to enhance the safety or the steering performance of the turning traveling.

Next, the control threshold value change prohibiting means 6 will be described. The parameters for prohibiting the change of the control threshold include the amount of turning, the friction coefficient of the road surface, the vehicle speed, and the stepping speed of the brake pedal.

First, the prohibition based on the turning amount will be described. The control threshold change prohibiting means 6 obtains information indicating that the turning amount is equal to or less than a predetermined value based on a signal from each of the rudder sensors 4. In step 5, an operation prohibition command is issued so that the control threshold value is not changed.

That is, even when the turning speed is high, when the turning is performed by the driver's normal intention, the turning amount is usually suppressed to a predetermined value or less. The ABS control is executed, and the control threshold value changing means 5 is operated when the steering amount exceeds a predetermined value.

FIG. 6 is a flowchart showing a prohibition control for changing the control threshold based on the steering amount. In step S2, the steering speed dθH / dt is set to a predetermined value.
When larger than A ₀ further steering amount θ in step S7
It is determined whether or not H is equal to or greater than a predetermined value B. When the H is equal to or greater than the predetermined value B, the control threshold is changed in the lock deepening direction to perform the ABS control. ABS control is performed.

To explain the prohibition of the change of the control threshold value based on the road surface friction coefficient, the control threshold value change prohibition means 6 obtains the information that it is higher than a predetermined value for the road surface friction coefficient based on the wheel deceleration and the wheel acceleration. And an operation prohibition command is issued to the control threshold changing means 5 so that the control threshold is not changed.

That is, even when the turning speed is high, if the friction coefficient of the road surface is high, the braking distance until the vehicle stops even with the normal ABS control is not so long. Then, normal ABS control is executed, and the control threshold value changing means 5 is operated when the coefficient of friction of the road surface is equal to or less than a predetermined value.

FIG. 7 is a flow for prohibiting the change of the control threshold value based on the friction coefficient μ of the road surface.
When .theta.H / dt is greater than the predetermined value A ₀ is further subjected to determination of friction coefficient of the road surface μ of whether low in step S8,
When the control threshold value is low, the control threshold value is changed in the lock deepening direction to perform the ABS control, and when the control threshold value is high, the normal ABS control is performed without changing the control threshold value.

The prohibition of the control threshold change based on the vehicle speed (pseudo-vehicle speed) will be described. The control threshold change prohibiting unit 6 obtains the information that the vehicle speed is equal to or less than a predetermined value.
An operation prohibition command is issued so that the control threshold value is not changed.

That is, even when the steering speed is high, when the vehicle speed is low, the braking distance until the vehicle stops even in the normal ABS control is not so long. The control is executed, and the control threshold value changing means 5 is operated at a high vehicle speed.

Figure 8 is a flow for inhibiting a change in the control threshold based on the vehicle speed, when the steering speed dθH / dt is greater than the predetermined value A ₀ in step S2, the further the vehicle speed V in step S9
There performs determination of whether or not a predetermined value greater than or equal _to V _0, performs ABS control and change the direction deeper lock the control threshold at high vehicle speed, the normal ABS control without at the time of low vehicle speed for changing the control threshold Will do it.

The control threshold change prohibiting means 6 will be described. When the control threshold change prohibiting means 6 obtains information that the brake pedal depressing speed is equal to or less than a predetermined value, the control threshold changing means 5 changes the control threshold. An operation prohibition command is issued to prevent the operation from being performed.

In other words, even when the turning speed is high, when the driver depresses the brake pedal with normal intention, the brake pedal depressing speed is usually suppressed to a predetermined value or less. Normal AB to
This is to execute the S control, and to activate the control threshold value changing means 5 when the brake pedal is suddenly depressed.

Figure 9 is a flow for inhibiting a change in the control threshold based on the brake pedal depression speed, when the steering speed dθH / dt is greater than the predetermined value A ₀ in step S2, the further
Brake pedal depression speed V _B in step S10 is performed to determine whether or not a predetermined value V _B0 or performs ABS control and change the direction deeper lock the control threshold when the brake pedal suddenly stepped,
When the brake pedal depression speed is low, normal ABS control is performed without changing the control threshold.

The above-described prohibition of the change of the control threshold is an example in which the control threshold is changed separately for each parameter. However, in some cases, the control threshold is changed in the lock deepening direction only when all the conditions according to the above parameters are all satisfied. It is better to do. No.
10 the figure indicate the flow of control in this case, when the steering speed dθH / dt is greater than the predetermined value A ₀ (step
S2), further steering amount θH determination that is equal to or greater than a predetermined value B, the determination that the road friction coefficient μ is low, determination that the vehicle speed V is a predetermined value greater than or equal to V _0, and the brake pedal depression speed V _B
There only when there all the determination that more than a predetermined value V _B0 (step S7 to S10), thereby performing the change control threshold to the lock deep direction.

[Brief description of the drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a configuration diagram of a control system of the embodiment, FIG. 2 is an overall configuration diagram of an anti-skid brake device, FIG. 3 is a slip ratio and a friction coefficient, and a lateral drag coefficient. FIG. 4 is a time chart of the normal ABS control, FIG. 5 is a flowchart showing a base mode of the control threshold change, and FIG. 6 is a prohibition of the control threshold change based on the steering amount. FIG. 7 is a flowchart showing inhibition of control threshold change based on friction coefficient. FIG. 8 is a flowchart showing inhibition of control threshold change based on vehicle speed. FIG. 9 is control based on brake pedal depression speed. FIG. 10 is a flowchart showing the prohibition of the change of the threshold value, and FIG. 10 is a flowchart showing the prohibition of the change of the control threshold value in consideration of all of the steering amount, the friction coefficient, the vehicle speed and the brake pedal depressing speed. DESCRIPTION OF SYMBOLS 1 ... Wheel speed detecting means 2 ... Braking pressure adjusting means 3 ... Control means 4 ... Steering angle sensor (means for detecting the turning amount and turning speed) 5 ... Control threshold changing means 6 ... Control threshold changing Prohibiting means 11-14 Wheels 21-24 Brake device 26 Brake pedal 30, 31, 33 Valve unit (braking pressure adjusting means) 35 Brake sensor (stepping speed detecting means)

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Tsuyama 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP-A-3-217361 (JP, A) JP-A-2 JP-A-68252 (JP, A) JP-A-61-232952 (JP, A) JP-A-63-219464 (JP, A) JP-A-62-253560 (JP, A) JP-A-60-1061 (JP, A) JP-A-62-279157 (JP, A) JP-A-3-60163 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60T 8/58 B60T 8/72

Claims (5)

(57) [Claims] 1. A wheel speed detecting means for detecting a rotation speed of a wheel, a braking pressure adjusting means for adjusting a braking pressure of a wheel, and a predetermined control threshold based on a wheel speed detected by the wheel speed detecting means. An anti-skid brake device for a vehicle, comprising: a control means for controlling the braking pressure adjusting means so as to increase and decrease the braking pressure, wherein the steering speed detecting means detects a steering speed; and vehicle turning speed to be detected, characterized in that a control threshold value changing means for changing the control threshold in the direction in which the braking efficiency is increased wheel when the predetermined high speed value a ₀ or more Anti-skid brake device. A turning amount detecting means for detecting a turning amount; and a change of the control threshold value by the control threshold value changing means is prohibited when the turning amount detected by the turning amount detecting means is equal to or less than a predetermined value. And a control threshold change prohibiting means.
An anti-skid brake device for a vehicle according to claim 1. 3. A friction coefficient detecting means for detecting a friction coefficient of a road surface, and when the friction coefficient of the road surface detected by the friction coefficient detecting means is equal to or more than a predetermined value, change of the control threshold value by the control threshold value changing means is prohibited. The anti-skid brake device for a vehicle according to claim 1, further comprising a control threshold value change prohibiting unit. 4. A vehicle control apparatus comprising: vehicle speed detecting means for detecting a vehicle speed; and control threshold value change prohibiting means for prohibiting the control threshold value changing means from changing the control threshold value when the vehicle speed detected by the vehicle speed detecting means is equal to or lower than a predetermined value. The anti-skid brake device for a vehicle according to claim 1, wherein: 5. A control threshold value changing means for detecting a stepping speed of a brake pedal, and a control threshold value changing means when the stepping speed detected by the brake pedal stepping speed detecting device is equal to or less than a predetermined value. The anti-skid brake device for a vehicle according to claim 1, further comprising a control threshold value change prohibiting unit that prohibits the control threshold change.