JP2863294B2 - 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. In other words, this system improves the maneuverability by controlling the braking pressure with the target of a low slip ratio when the rotation angle of the steering wheel is large, and increases the braking pressure with the target of a high slip ratio when the rotation angle of the steering wheel is small. By performing the 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 the depression state of the brake pedal of the driver and changes the threshold value of the braking pressure control according to the depression state. Things.

That is, as shown in FIG. 1, a specific means for this is a wheel speed detecting means 1 for detecting a rotational speed of a wheel.
A braking pressure adjusting means 2 for adjusting the braking pressure of the wheels; and a braking pressure adjusting means 2 for increasing or decreasing the braking pressure according to a predetermined control threshold based on the wheel speed detected by the wheel speed detecting means 1. A brake pedal depression state detection means 4 for detecting a depression state of a brake pedal, and a brake pedal detected by the brake pedal depression state detection means 4 on the premise of an anti-skid brake device for a vehicle having a control means 3 for controlling the vehicle. And control threshold value changing means 5 for changing the control threshold value based on the stepping-on state.

When the brake pedal depressing state detecting means 4 detects the depressing speed of the brake pedal, the control threshold changing means 5 changes the control threshold to a direction in which the braking efficiency of the wheel becomes higher when the depressing speed is equal to or higher than a predetermined value. It shall be.

When the brake pedal depression state detecting means 4 detects the depression amount of the brake pedal, the control threshold value changing means 5 determines the limit from the detected depression amount when the depression amount is equal to or more than the predetermined limit depression amount. It is assumed that the control threshold value is changed such that the greater the value obtained by subtracting the stepping amount, the higher the braking efficiency of the wheel.

When detecting the stepping speed of the brake pedal, a turning amount detecting means for detecting a turning amount is provided, and when the turning amount detected by the turning amount detecting means exceeds a predetermined limit turning amount,
The control threshold value can be changed such that the greater the value obtained by subtracting the limit turning amount from the detected turning amount, the higher the braking efficiency of the wheel becomes.

Further, a vehicle speed detecting means for detecting a vehicle speed may be provided, and when the brake pedal depressing speed is equal to or higher than a predetermined value, the control threshold value may be changed such that as the vehicle speed increases, the braking efficiency of the wheels increases.

In the case where the control threshold value is changed based on the brake pedal depression amount, a control threshold value correction unit 7 for correcting the change amount of the control threshold value by the control threshold value changing unit 5 in a direction in which the braking efficiency of the wheel increases as the vehicle speed increases is provided. You may.

Further, even if the stepping speed of the brake pedal is equal to or higher than a predetermined value, when the amount of steering is equal to or lower than the predetermined value or when the amount of pressing of the brake pedal is equal to or lower than the predetermined value, the control threshold changing unit 5 may change the control threshold. It is also possible to provide a control threshold value change prohibiting means 6 for prohibiting.

(Operation) The above-described anti-skid brake device is provided with a means for changing the threshold value for the braking pressure control based on the depression state of the brake pedal. At the time of stepping on), the vehicle is stopped at a shorter braking distance than normal by changing the control threshold value so that the braking pressure acts on the wheels in a slightly more locking manner than normal, that is, the braking efficiency of the wheels is increased. That can be done.

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 brake pedal is suddenly depressed is a state in which the driver has inadvertently depressed the brake pedal in order to avoid danger, for example, a state of panic. Turning the vehicle by operating the steering wheel is usually 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, when the brake pedal depression amount exceeds the limit depression amount, the control threshold value may be changed so that the greater the value obtained by subtracting the limit depression amount from the detected depression amount, the higher the braking efficiency of the wheel becomes. , The degree of panic of the driver is determined from the amount of depression of the brake pedal, and the degree of panic is determined according to the degree.
ABS control can be performed.

Further, in the change of the control threshold at the time of sudden depression of the brake pedal, when the detected turning amount exceeds the limit turning amount, the larger the value obtained by subtracting the limit turning amount from the detected turning amount, the larger the value. To increase the braking efficiency of the wheels,
In other words, if the control threshold is changed so that the lock becomes deeper, the braking efficiency can be adjusted according to the degree of the panic state of the driver.

Further, as described above, when the control threshold value is changed based on the brake pedal depressing speed, if the vehicle speed is higher, the braking efficiency of the wheels is made higher. When the vehicle speed is high, the braking efficiency can be increased and the vehicle speed can be stopped quickly.

Even in the case where the change amount of the control threshold value is determined according to the brake pedal depression amount, if the change amount is corrected in a direction in which the higher the vehicle speed, the higher the braking efficiency of the wheels, the more the vehicle speed is changed.
ABS control can be performed.

Further, even when the stepping speed of the brake pedal is equal to or higher than a predetermined value, if the determination is made as to whether or not to make the above change by checking the amount of steering or the amount of stepping on the brake pedal, it is possible to truly drive the vehicle. Only when the driver is in a panic or when it is actually difficult to avoid the danger by turning the vehicle, the danger can be avoided by controlling the lock.

In other words, when the steering amount is equal to or less than the predetermined value or when the brake pedal depression amount is equal to or less than the predetermined value, the result is that the steering is performed or the brake pedal is depressed by the driver's normal intention. Since the driver is not panicked, the control threshold value changing means is prohibited from changing the control threshold value, so that danger can be avoided by turning.

(Effects of the Invention) Therefore, according to the present invention, in the anti-skid brake device for a vehicle, the threshold value for the braking pressure control is changed based on the depression state of the brake pedal. When it is high or when the amount of depression of the brake pedal is large, for example, when the driver is in a panic state, the braking pressure is controlled so as to be locked and the braking performance is secured.
This makes it possible to perform control according to the situation where the driver or the vehicle is located, such as performing the ABS control to ensure the steering stability of the vehicle.

In addition, when the brake pedal depression speed is high, and when the turning amount exceeds the limit turning amount, if the amount of change of the control threshold is determined according to the exceeded amount, the panic degree of the driver can be reduced. ABS control can be performed by grasping more in accordance with actual conditions.

Also, when the stepping speed of the brake pedal is high, the braking efficiency of the wheels is increased as the vehicle speed increases, or when the amount of change of the control threshold value is determined in accordance with the amount of stepping on the brake pedal, Is corrected in such a direction that the higher the vehicle speed, the higher the braking efficiency of the wheels, the ABS control according to the actual situation of the vehicle can be performed.

Also, when the control threshold value is changed, if the above-mentioned change is determined based on the steering amount or the depression amount of the brake pedal, the situation in which the driver or the vehicle is placed can be improved. The control can be performed by grasping in accordance with the above.

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

As shown in FIG. 2, in the vehicle according to this embodiment, the left and right front wheels 11, 12 are driven wheels, the left and right rear wheels 13, 14 are drive wheels, and the output torque of the engine 15 is The transmission is transmitted to left and right rear wheels 13 and 14 via a propeller shaft 17, a differential device 18 and 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 brake pressure supply line 29 for the front wheels extending from the master cylinder 28 branches into a brake pressure supply line 29a for the left front wheel and a brake pressure supply line 29b for the right front wheel, and the calipers 21a and 22b of the brake devices 21 and 22 respectively. It is connected. The left front wheel braking pressure supply line 29a is provided with a first valve unit 30 including an electromagnetic on-off valve 30a and an electromagnetic relief valve 30b.
b is provided with a second valve unit 31 including an electromagnetic on-off valve 31a and an electromagnetic relief valve 31b.

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, a stepping speed and a stepping amount of the brake pedal 26, 11-14
The wheel speed signals from the wheel speed sensors 37 to 40 as the wheel speed detecting means 1 for detecting the rotation speed of the vehicle and the steering angle signals (steering amount, steering speed) from the steering angle sensor 41 are input, and 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 and control threshold value correcting means 7 are provided, and the open / close valves 30a,
The opening and closing of the relief valves 31a, 33a and the relief valves 30b, 31b, 33b are controlled 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, and compares the control threshold value with the wheel acceleration / deceleration and the slip ratio to determine a phase 0 (ABS non-control state) and a 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.

<Pseudo-vehicle speed setting> The above-mentioned pseudo-vehicle speed Vr is set as a vehicle speed for convenience based on the above-mentioned wheel speed since the vehicle speed when the wheels 11 to 14 are slipping cannot be accurately detected. The maximum wheel speed of the four wheels 11 to 14 is set to the pseudo vehicle body speed Vr, and the speed change amount is changed from 1.2 GGΔt at the high friction coefficient to 0.3 G at the low friction coefficient according to the friction coefficient of the road surface.・
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) <Setting of control threshold> The control threshold is set independently for each channel. First wheel deceleration threshold value G1 for determining transition from phase 0 (when ABS is not controlled) to phase I (decompression), and second wheel deceleration threshold value for determining transition from phase I to phase II (holding)
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 lateral drag 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.

<Normal ABS Control> Therefore, normally, the increase / decrease control of the braking pressure as shown in FIG. 4 is performed.

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.

When the slip ratio decreases along with the above-described pressure reduction and exceeds the first slip ratio threshold value S1, phase III is selected, and the braking pressure is rapidly increased.

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

Due to the above-described slow pressure increase, the slip ratio becomes the second slip ratio threshold value.
Beyond S2, 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.

<Change of Control Threshold> -Change Based on Pedal Depressing Speed- The control threshold is changed basically according to the stepping speed Bv of the brake pedal 26 obtained by the brake sensor 35. That is, when the stepping speed Bv is equal to or higher than the predetermined value Bvo, the control threshold value is changed to a direction in which the braking efficiency of the wheel is increased (lock is deepened).

In this case, the stepping speed equal to or higher than the predetermined value Bvo is, for example,
Stepping when the vehicle suddenly jumps from the side of the road to the front of the vehicle while driving, causing the driver to temporarily panic and inadvertently depressing the brake pedal to avoid danger Speed. 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 equal to or higher than the stepping speed Bvo is obtained, the first wheel deceleration threshold value G1 for determining transition from phase 0 (when ABS is not controlled) to phase I (decompression), The first slip ratio threshold S2 for determining the transition from phase II (reduced pressure holding) to phase III (sudden pressure increase) and the phase IV, so that the deceleration threshold G2 for determining transition to II (hold) is increased. Is higher than the second slip ratio threshold S2 for determining the transition from the phase I to the phase I, that is, the pseudo vehicle speed Vr
The thresholds G3 are changed in a predetermined manner so as to increase the depth, and to lower the wheel acceleration threshold G3 for determining transition from phase III to phase IV (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).

FIG. 5 is a flow showing the control of changing the control threshold value. When a brake signal and each wheel speed signal signal are input and the brake pedal depression speed Bv is larger than a predetermined value Bvo,
ABS control is performed by changing the control threshold value in the lock deepening direction (steps S1 to S3). When the stepping speed Bv is less than the predetermined value Bvo, normal ABS control is performed without changing the control threshold (step S4).

Therefore, for example, when there is a sudden jump from the side of the road to the front of the vehicle while the vehicle is running, the driver temporarily panics, and the brake pedal 26 is suddenly and strongly depressed, which is more than usual. By performing the ABS control with the lock deepened, the braking efficiency of the wheels is increased, and the vehicle can be stopped at a short braking distance. On the other hand, when the brake pedal 26 is depressed by the driver's intention, normal ABS control is performed, so that the wheels can appropriately obtain the lateral drag required for turning, and the stability of turning can be improved. Or, the steering performance can be improved.

—Change Based on Pedal Depressing Speed and Steering Amount— The control threshold is changed in consideration of the turning amount obtained by the steering angle sensor 41 in the above-described brake pedal depressing speed. That is, when the actual turning amount θH exceeds the limit turning amount θHm, the limit threshold is changed in a direction in which the lock becomes deeper as the value b obtained by subtracting the limit turning amount θHm from the actual turning amount θH increases. Is what is done.

In this case, the limit turning amount θHm is a turning amount that makes it impossible to perform a turning operation corresponding to the steering angle (for example, causes over-steering), and includes the vehicle speed v and the road surface friction coefficient μ. It is calculated from the map shown in FIG.

FIG. 7 is a flow of the change control. When the brake pedal depression speed Bv is larger than a predetermined value Bvo in step S2, if the value b is equal to or less than zero, the normal ABS control is performed without changing the control threshold. Perform (Step S7). And
When the value b is larger than zero, that is, when the actual turning amount θH exceeds the limit turning amount θHm, the control threshold change amount β is calculated from the map based on this b to change the control threshold (step S2-S6).

The magnitude of the value b can be considered to represent the degree to which the driver is panicked. Therefore, in this example in which the amount of change of the control threshold is changed in accordance with the value b, ABS control can be performed according to the panic state of the driver.

—Change Based on Pedal Depression Speed and Vehicle Speed— The control threshold value is changed in consideration of the vehicle speed in addition to the brake pedal depression speed described above. That is, when the brake pedal depression speed Bv is higher than the predetermined value Bvo, the control threshold value is changed so that the lock is deeper as the vehicle speed is higher.

FIG. 8 is a flow of the change control. When the brake pedal depression speed Bv is larger than the predetermined value Bvo in step S2, the control threshold change amount γ is calculated from the map based on the vehicle speed v, and the control threshold change is performed. Perform (Steps S2 to S6).

-Control threshold change prohibition-The parameters for prohibiting the change of the control threshold include a turning amount, a turning speed, and a brake pedal depression amount.

More specifically, based on a signal from the steering angle sensor 4, the turning speed dθH / dt is less than a predetermined value A or the turning amount θ
When the information that H is less than the predetermined value θH ₀ or when the information that the brake pedal depression amount Bt is less than the predetermined value B _t0 is obtained from the brake sensor 35, the control threshold changing unit 5 sends the control threshold An operation prohibition command is issued so as not to change the.

That is, even when the brake pedal 26 is suddenly depressed, when the steering or the depression of the brake pedal 26 is performed by the driver's normal intention, the steering speed, the steering amount or the depression amount of the brake pedal 26 is suppressed to a predetermined value or less. Normally, in such a case, normal ABS control is executed, and when the turning speed, the turning amount, or the depression amount of the brake pedal 26 exceeds a predetermined value, the control threshold is changed. is there.

FIG. 9 is a flowchart showing a control for inhibiting the control threshold value from being changed.
When greater than o further turning speed dθH / dt is equal to or greater than the predetermined value A, the turning amount .theta.H predetermined value .theta.H ₀ or more, and when the depression amount Bt of the brake pedal to obtain a determination that the predetermined value B _t0 or more ABS control is performed by changing the control threshold value in the lock deepening direction, and normal ABS control is performed without changing the control threshold value when any one is less than the predetermined value (steps S3 to S7).

In this example, the control threshold is changed when all of the turning speed, the turning amount, and the depression amount of the brake pedal are equal to or more than a predetermined value. When it is obtained, the control threshold may be changed.

-Change based on pedal depression amount-The control threshold value is changed when the depression amount Bt of the brake pedal 26 obtained by the brake sensor 35 exceeds a predetermined limit depression amount, so that the braking efficiency of the wheel is increased (lock depth is increased). ) Direction.

That is, when the actual brake pedal depression amount Bt exceeds the limit depression amount Bt1 that causes the locking of the wheels, Bt1
The control threshold value is changed in such a manner that the lock becomes deeper as the value a obtained by subtracting the larger value becomes larger. In this case, the ABS control is started when the wheels start to lock, and the brake pedal depression amount at this time is the limit depression amount Bt1. Then, the control threshold change amount is corrected according to the magnitude of the vehicle speed v. It should be noted, it is a Bt1> B _t0.

FIG. 10 is a flowchart showing this change control. When the value a is larger than zero, the control threshold change amount α is calculated from the map based on this value a to determine the control threshold change amount. Then, the correction amount is calculated according to the vehicle speed v to correct the change amount (steps S2 to S6). If a ≦ 0, normal ABS control is performed without changing the control threshold (step S7).

In this case, a> 0, that is, the brake pedal depression amount Bt
Is larger than the limit depression amount Bt1, the magnitude of this value a can be considered to represent the degree to which the driver is panicked. Therefore, in this example in which the amount of change of the control threshold is changed according to the value a, the ABS control can be performed according to the panic state of the driver.

-Comprehensive control-The control threshold change control described above is an example in which each control parameter is separately performed. However, in some cases, the control threshold is changed in the lock deepening direction in consideration of all the conditions based on the respective parameters. It is better to do it. Eleventh
The figure shows the control flow in that case.

That is, after the input of various data, when the brake pedal depression speed Bv is larger than the predetermined value Bvo, a value a obtained by subtracting the limit depression amount Bt1 from the actual brake pedal depression amount Bt.
Is larger than zero, and if so, a control threshold change amount α corresponding to a is obtained (steps S1 to S4). Next, it is determined whether a value b obtained by subtracting the limit turning amount θHm from the actual turning amount θH is larger than zero.
Control threshold change amount β according to (Steps S5 and S5)
6). Next, the control threshold change amount γ according to the vehicle speed v is obtained (step S7).

When the turning speed dθH / dt is equal to or more than the predetermined value A, the turning amount θ
When it is determined that H is equal to or greater than a predetermined value θHo and the brake pedal depression amount Bt is equal to or greater than a predetermined value Bto, the above α + β +
γ is calculated to obtain the final control threshold change amount, and based on this, ABS control with the control threshold changed is performed (step S8).
To S12), when the above determination cannot be obtained, normal ABS control is performed without changing the control threshold (step S13).

In the case of a vehicle having a four-wheel steering system in which the rear wheels are also steered when the front wheels are steered, when the control threshold value is changed to a lock deeper, the steering ratio of the rear wheels to the front wheels is simultaneously increased. May be corrected to the same phase to improve the running stability of the vehicle. This correction of the steering ratio is particularly useful during high-speed running.

[Brief description of the drawings]

FIG. 1 is a block diagram of the present invention, FIG. 2 and subsequent figures show an embodiment of the present invention, FIG. 2 is a diagram showing the overall configuration of an anti-skid brake device, and FIG. FIG. 4 is a time chart of normal ABS control, FIGS. 5 and 7 to 11 are flow charts of control threshold value change control, and FIG. 6 is a limit steering amount. It is a characteristic diagram. DESCRIPTION OF SYMBOLS 1 ... Wheel speed detecting means 2 ... Braking pressure adjusting means 3 ... Control means 5 ... Control threshold change means 6 ... Control threshold change prohibiting means 7 ... Control threshold correction means 11-14 ... Wheels 21-24 ... Brake device 26 ... Brake pedal 30, 31, 33 ... Valve unit (braking pressure adjusting means) 35 ... Brake sensor (Pedal stepping speed and stepping amount detecting means) 41 ... Steering angle sensor (Steering amount and Steering speed detection means)

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-248466 (JP, A) JP-A-60-209355 (JP, A) JP-A-4-110265 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) B60T 8/58 B60T 8/66

Claims (8)

(57) [Claims] A wheel speed detecting means for detecting a rotational speed of the wheel; a braking pressure adjusting means for adjusting a 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 and decrease the braking pressure, wherein the brake pedal depression state detecting means for detecting a depression state of a brake pedal; An anti-skid brake device for a vehicle, comprising: control threshold changing means for changing the control threshold based on a depressed state of a brake pedal detected by a state detecting means. 2. The brake pedal depression state detecting means detects a depression speed of a brake pedal, and the control threshold value changing means causes the braking efficiency of the wheel to increase when the depression speed is equal to or higher than a predetermined value. The anti-skid brake device for a vehicle according to claim 1, wherein the control threshold value is changed. 3. The brake pedal depression state detecting means detects the depression amount of the brake pedal, and the control threshold value changing means detects the detected depression amount when the depression amount exceeds a predetermined limit depression amount. The anti-skid brake device for a vehicle according to claim 1, wherein the control threshold value is changed so that the greater the value obtained by subtracting the limit stepping amount from the vehicle, the higher the braking efficiency of the wheel becomes. A turning amount detecting means for detecting a turning amount;
The brake pedal depressed state detecting means detects the depressing speed of the brake pedal, and the control threshold value changing means includes:
When the stepping speed is equal to or more than a predetermined value and the turning amount detected by the turning amount detecting means exceeds a predetermined limit turning amount,
The anti-skid brake device for a vehicle according to claim 1, wherein the control threshold value is changed such that the greater the value obtained by subtracting the limit turning amount from the detected turning amount, the higher the braking efficiency of the wheel becomes. 5. The vehicle according to claim 1, further comprising a vehicle speed detecting means for detecting a vehicle speed, wherein the brake pedal depression state detecting means detects a brake pedal depression speed, and the control threshold value changing means detects when the depression speed is equal to or higher than a predetermined value. The anti-skid brake device for a vehicle according to claim 1, wherein the control threshold value is changed such that the higher the vehicle speed detected by the vehicle speed detection means, the higher the wheel braking efficiency. 6. A vehicle speed detecting means for detecting a vehicle speed, and a control threshold value for correcting the amount of change of the control threshold value by the control threshold value changing means as the vehicle speed detected by the vehicle speed detecting means becomes higher, so that the braking efficiency of the wheel becomes higher. The anti-skid brake device for a vehicle according to claim 3, further comprising a correction unit. 7. A turning amount detecting means for detecting a turning amount, and a control for inhibiting a control threshold value changing means from changing a control threshold when the turning amount detected by the turning amount detecting means is equal to or less than a predetermined value. The anti-skid brake device for a vehicle according to claim 2, further comprising a threshold change prohibiting unit. 8. A brake pedal depression amount detecting means for detecting a depression amount of a brake pedal, and a change of a control threshold value by the control threshold value changing means when the depression amount detected by the brake pedal depression amount detection means is equal to or less than a predetermined value. The anti-skid brake device for a vehicle according to claim 4, further comprising a control threshold value change prohibiting unit that prohibits the control.