JPH04183665A - Anti-skid brake device for vehicle - Google Patents

Abstract

PURPOSE:To provide good transient response by setting the next initial rapid pressure increase amount for possible setting of braking pressure with good response when a road surface condition changes, based on acceleration and deceleration of wheels immediately after rapid pressure increase in the previous cycle. CONSTITUTION:In a brake control system 15 where the first and second channels which controls braking pressure of braking devices in right and left front wheels 1, 2 by action of the first and second valve units 20, 21, and the third channel which controls braking pressure of braking devices 13, 14 in right and left rear wheels 13, 14 are provided, the valve units 20-23 are controlled to make a rapid pressure increase at the initial time of a pressure increase phase through a control unit 24. In this case, acceleration and deceleration of wheels are computed based on wheel speed detected by wheel speed sensors 26-29, and based on acceleration and deceleration computed immediately after rapid pressure increase in the previous cycle, the rapid pressure increase amount at the initial time of the next pressure increase phase is set.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an anti-skid brake device that suppresses excessive braking force when braking a vehicle, and in particular to an anti-skid brake device that suppresses excessive braking force when braking a vehicle. The present invention relates to an anti-skid brake system for a vehicle that periodically controls the increase and decrease of the brake.

(Prior Art) A vehicle brake system is sometimes equipped with an anti-skid brake device for the purpose of preventing wheel locking or skidding during braking.

Generally, this type of anti-skid brake device is equipped with a wheel speed sensor that detects the rotational speed of the wheel and an electromagnetic control valve that adjusts the brake oil pressure. When the deceleration decreases below a predetermined deceleration, the electromagnetic control valve is pressure-reduced to lower the braking pressure, and the reduction in braking pressure restores the rotational speed of the wheels, so that, for example, the acceleration determined from the wheel speed becomes a predetermined value. When the acceleration reaches , the braking pressure is increased by the control valve and the pressure increase M114. Then, a series of such braking pressure controls (hereinafter referred to as
For example, by continuing to perform ABS control (ABS control) until the vehicle comes to a stop, it is possible to prevent the wheels from locking or skidding during sudden braking, and to stop the vehicle in a short braking distance without losing directional stability. It becomes possible to do so.

Incidentally, in this type of ABS control, the rate of increase in braking pressure after pressure reduction is very important. In other words, if the pressure increase rate is slowed down, the time until the next braking force acts on the wheels becomes longer, resulting in a reduction in braking performance. On the other hand, if the pressure increase speed is too high, even if pressure increase control is stopped, the braking pressure will rise beyond the appropriate value due to the inertia of the brake oil, causing excessive braking force to be applied to the wheels, resulting in problems with control accuracy. Another problem will occur.

For example, in response to such problems,
The publication describes that in this type of anti-skid brake device, the braking pressure is increased rapidly with a large pressure gradient at the beginning of the pressure increase phase, and then increased with a smaller pressure gradient, and the time of the sudden pressure increase is increased. A configuration is shown in which the setting is made dependent on the amount of sudden pressure increase in the preceding cycle. According to this, the braking pressure rises rapidly at the beginning of the pressure increase phase, so good control response is obtained, and at the end of the pressure increase phase, the time change in pressure increase is small, so the braking pressure is increased rapidly. The pressure increase limit can be easily managed and good control accuracy can be expected.

(Problem to be Solved by the Invention) However, in the prior art described in the above publication, the surge pressure time after pressure reduction is set based on the actual value of the surge pressure amount of the previous cycle. The behavior of the wheels after the rapid pressure increase is not reflected in the next rapid pressure increase time, and therefore there remains an issue to be solved in terms of transient response when the road surface condition changes.

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, an object of the present invention is to further improve the control performance of an anti-skid brake device that performs rapid pressure increase at the initial stage of pressure increase.

(Means for Solving the Problems) First, an anti-skid brake device for a vehicle according to the invention according to claim 1 of the present application (hereinafter referred to as the first invention) includes a wheel speed detection means for detecting the rotational speed of a wheel; The brake hydraulic pressure is periodically increased or decreased according to a cycle including a pressure increase phase, a pressure decrease phase, and a holding phase after pressure decrease based on a hydraulic pressure adjusting means for adjusting the brake hydraulic pressure and the wheel speed detected by the wheel speed detection means during braking. and a control means for activating the hydraulic pressure adjusting means so as to rapidly increase the pressure at the beginning of the pressure increase phase, the acceleration/deceleration of the wheels is controlled based on the wheel speed detected by the wheel speed detection means. wheel acceleration/deceleration calculating means for calculating; and initial surge pressure amount setting means for setting a sudden pressure amount at the beginning of the next pressure increase phase based on the acceleration/deceleration calculated by the acceleration/deceleration calculation means after the sudden pressure increase in the previous cycle; It is characterized by having the following.

Further, the anti-skid brake device for a vehicle according to the invention according to claim 2 of the present application (hereinafter referred to as the second invention) includes a wheel speed detection means for detecting the rotational speed of the wheel, and a hydraulic pressure for adjusting the brake key oil pressure. The brake hydraulic pressure is periodically increased or decreased according to a cycle including a pressure increase phase, a pressure decrease phase, and a holding phase after pressure decrease based on the adjustment means and the wheel speed detected by the wheel speed detection means during braking, and the pressure increase and a control means for activating the hydraulic pressure adjusting means so as to rapidly increase the pressure at the beginning of the phase, wheel acceleration/deceleration calculation for calculating wheel acceleration/deceleration based on the wheel speed detected by the wheel speed detection means. and an initial surge pressure that sets an initial surge pressure amount such that the greater the acceleration of the wheel immediately after the surge pressure in the previous cycle calculated by this acceleration/deceleration calculation means, the greater the surge pressure amount at the beginning of the next pressure increase phase. The present invention is characterized in that it is provided with an amount setting means.

(Function) According to the first and second inventions, the next initial surge pressure amount is set based on the acceleration/deceleration of the wheels immediately after the surge pressure in the previous cycle, so braking is performed even when the road surface condition changes. Since the pressure is controlled with good responsiveness, good transient response can be obtained.

(Example) Examples of the present invention will be described below.

As shown in FIG. 1, in the vehicle according to this embodiment, the left and right front wheels 1.2 are driven wheels, the left and right rear wheels 3.4 are driving wheels, and the output torque of the engine 5 is transmitted from the automatic transmission 6. The power is transmitted to the left and right rear wheels 3.4 via the propeller shaft 7, the differential gear 8, and the left and right drive shafts 9, 10.

Each of the wheels 1 to 4 has discs lla to 14a that rotate integrally with these wheels 1 to 4, and calipers llb that brake the rotation of these discs 11a to 14a by receiving braking pressure. Brake devices 11 to 14 including brake devices 11 to 14b and the like are provided, respectively, and a brake control system 15 for controlling these brake devices 11 to 14 is also provided.

This brake control system 15 includes a booster 17 that increases the depression force of the brake pedal 16 by the driver, and a master cylinder 18 that generates braking pressure in accordance with the depression force increased by the booster 17. . The front wheel brake pressure supply line 19 led from the master cylinder 18 is branched into two routes, and these front wheel branch brake pressure lines 19a and 19b are connected to the left and right front wheels 1 and 2.
Caliper 11a, 1 of brake device 11.12 in
2a, and one front wheel branch braking pressure line 1 leading to the brake device 11 of the left front wheel 1.
A first valve unit 20 consisting of an electromagnetic on-off valve 20a and an electromagnetic relief valve 20b is installed at 9a, and a branch braking pressure line 19b for the other front wheel leading to the brake device 12 of the right front wheel 2 is installed. Similarly to the first valve unit 20, a second valve unit 2) consisting of an electromagnetic on-off valve 2)a and an electromagnetic relief valve 2)b is also installed.

On the other hand, the rear wheel braking pressure supply line 22 led from the master cylinder 18 includes an electromagnetic on-off valve 23a and an electromagnetic on-off valve 23a, similar to the first and second valve units 20.2). A third valve unit 23 consisting of a relief valve 23b is installed, and this rear wheel braking pressure supply line 22 is branched into two routes on the downstream side of the third valve unit 23, and is connected to these rear wheels. Branch braking pressure lines 22a, 22b are connected to calipers 13b, 14b of brake devices 13.14 on left and right rear wheels 3.4, respectively. That is, the brake control system 15 in this embodiment includes a first channel that variably controls the braking pressure of the brake device 11 on the left front wheel 1 through the operation of the first valve unit 20, and a first channel that variably controls the braking pressure of the brake device 11 on the left front wheel 1 through the operation of the second valve unit 2). Brake device 12 on front wheel 2
a second channel that variably controls the braking pressure of the left and right rear wheels 3.4 through the operation of the third valve unit 23;
channels are provided, and these first to third channels are controlled independently of each other.

The brake control system 15 includes the first to
A control unit 24 that controls the third channel is provided, and this control unit 24 receives a brake signal from a brake switch 25 that detects ON/FF of the brake pedal 16, and a wheel speed that detects the rotational speed of each wheel. Wheel speed signals from sensors 26 to 29 are input, and a braking pressure control signal corresponding to these signals is input to the first
~Third valve unit 20.2). 23, the braking control for slipping of the left and right front wheels 1.2 and rear wheels 3.4, that is, ABS control, is performed in the first
~It is designed to be performed in parallel for each third channel. That is, the control unit 24 controls the first to third valve units 20, 2), . 23
On-off valves 20a, 2)a, 23a and relief valve 2 in
0b, 2)b, and 23b are controlled to open and close by duty control, respectively, so that braking force is applied to the front wheels 1, 2 and the rear wheels 3, 4 with braking pressure depending on the state of slip. In addition, the first to third valve units,
20,2). Each relief valve 20b, 2 in 23
)b.

The brake oil discharged from 23b is returned to the reservoir tank 18a of the master cylinder 18 via a drain line (not shown).

In the ABS non-control state, the control unit 24 does not output a braking pressure control signal, so as shown in the figure, the first to third valve units 20,
2). Relief valves 20b, 2)b, 23b in 23
are each held closed, and each unit 20, 2). 2
The on-off valves 20a, 2)a, and 23a of No. 3 are held open, so that the braking pressure generated in the master cylinder 18 in response to the depression force of the brake pedal 16 is transferred to one braking pressure supply line for the front wheels and Braking pressure supply line 22 for rear wheels
is supplied to the brake devices 11 to 14 on the left and right front wheels 1.2 and rear wheels 3, 4 through the brakes, and braking force corresponding to these braking pressures is applied to the front wheels 1, 2 and rear wheels 3, 4. It will be given directly.

Next, an outline of the brake control performed by the control unit 24 will be explained.

In other words, the control unit 24 controls the sensor 2.
Acceleration and deceleration for each wheel are calculated based on the wheel speeds indicated by signals from 6 to 29. Here, to explain how to calculate acceleration or deceleration, the control unit 24 divides the difference between the current wheel speed value and the previous wheel speed value by the sampling period Δt (for example, 7 m5), and converts the result into the gravitational acceleration. The converted value is updated as the current acceleration or deceleration.

Furthermore, the control unit 24 executes a predetermined rough road determination process to determine whether the road surface the vehicle is traveling on is a rough road or not. This rough road determination process is executed, for example, as follows. In other words,
For example, if the deceleration or acceleration of the rear wheels 3.4 exceeds a predetermined upper limit or lower limit within a certain period of time or is within a set value, the control unit 24 sets a rough road flag F A.
If the KRO is maintained at O and the number of times the acceleration and deceleration values exceed the upper and lower limits within a certain period of time is greater than or equal to the set value, the road surface is determined to be rough and the road is marked as rough. Set RO to 1 in flag FA.

The control unit 24 controls the rear wheels 3.4 to represent the wheel speed and acceleration/deceleration for the third channel.
Select. In this embodiment, the smaller of the two wheel speeds is selected as the rear wheel speed in consideration of the detection error of both wheel speed sensors 28 and 29 of the rear wheels 3.4 at the time of slipping. The acceleration and deceleration determined from the wheel speed are selected as the rear wheel deceleration and rear wheel acceleration.

Furthermore, the control unit 24 estimates the road surface friction coefficient for each channel and calculates the pseudo body speed of the vehicle in parallel.

The control unit 24 includes the wheel speed sensor 28.
29 and the left and right front wheels 1.29 indicated by the signals from the wheel speed sensors 26 and 27.
The slip rates for the first to third channels are calculated from the wheel speed and pseudo-vehicle speed in Section 2. In this case, the following relational expression: Slip/slip ratio - (wheel speed/pseudo-vehicle speed) The slip rate is calculated using X100. In other words, the larger the deviation of the wheel speed from the pseudo vehicle speed, the smaller the slip rate becomes, and the greater the tendency of the wheel to slip.

Subsequently, the control unit sets various control threshold values used to control the first to third channels.

Here, the outline of the control threshold setting process will be described. This control threshold setting process is performed, for example, as follows. That is, the control unit 24 selects the control threshold corresponding to the friction coefficient value MU and the pseudo vehicle speed 8 from various control thresholds set in advance according to the vehicle speed range and the road surface friction coefficient, and also controls these control thresholds. The threshold value is corrected according to the judgment result of the rough road judgment process. Here, the control threshold is, for example, the Q-2 deceleration threshold B for determining the transition from phase 0, which indicates an ABS non-control state, to face ■, which indicates a holding state after pressure increase. 2, a 1-2 deceleration threshold B1□ for determining the transition from phase ■ indicating the pressure increase state to the above phase ■, and a 2-3 deceleration threshold B1□ for determining the transition from the above phase ■ to the phase ■ indicating the pressure reduction state. A speed threshold B23,
From this phase ■, phase V indicates the holding state after depressurization.
3-5 deceleration threshold B35 for determining transition from phase V to phase I, 5-1 slip rate threshold B5□ for determining pressure increase from phase V to phase I, and initial slip rate threshold for the first cycle immediately after the start of control. Bl is set according to the vehicle speed range and the road surface friction coefficient. In this case, the deceleration threshold, which has a large effect on the braking force, is determined by adjusting the friction coefficient value MU in order to achieve a high level of both braking performance when the road surface friction coefficient is large and control responsiveness when the road surface friction coefficient is small. It is set so that the lower the level, that is, the lower the road surface friction coefficient, the closer it gets to OG. Note that the minimum value of the respective friction coefficient values of the first to third channels is used as the strong friction coefficient value MU.

Further, control threshold values are similarly set for the second and third channels.

The control unit 24 performs lock determination processing for each f-jannel and the first to third valve units 20, 2) . A phase determination process for defining the control amount for 23 and a cascade determination process are performed.

Here, the lock determination process will be explained as follows. For example, in the lock determination process for the first channel for the left front wheel, the control unit 24 first sets the continuation flag FC for the first channel.
After setting the current value of ON+ as the previous value, next set the pseudo vehicle speed V3 and wheel speed W1 under predetermined conditions (for example, V
R<5Km/H, W1<25Km/H) is satisfied or not, and when these conditions are satisfied, the continuation flag F C0NI and lock flag F LOK are set.
Reset each I to O, and if not satisfied, set l to 1 in the 90-tsk flag FLO that determines whether FLOKI is set to 1 or not.
If not set, the lock flag FLOKI is set to 1 under a predetermined condition (for example, when the pseudo vehicle speed VR is greater than the wheel speed W1).

On the other hand, the control unit 24 controls the lock flag FL.
When it is determined that oKl is set to 1, for example, the phase value P1 of the first channel is set to 5 indicating phase V, and when the slip rate S1 is greater than 90%, the continuation flag FCONI is set to 1. .

Note that lock determination processing is similarly performed for the second and third channels.

Further, to explain the outline of the phase determination process, the control unit 24 indicates the ABS non-control state by comparing each control threshold value set according to the driving state of the vehicle with the wheel acceleration/deceleration and slip rate. Phase O, phase that indicates the pressure increase state during ABS control ■
, phase (2) indicating a hold state after pressure increase, phase (3) indicating a pressure decrease state, phase 'to' indicating a rapid pressure decrease state, and phase V indicating a holding state after pressure decrease.

Furthermore, the above-mentioned cascade determination process determines a cascade lock state in which the wheels are locked continuously in a short period of time, because the wheels are likely to lock even with a small braking pressure, especially on low-friction road surfaces such as icy roads. The cascade flag FCAS is set to 1 when certain conditions that are likely to cause a cascade lock are met.
It is designed to be

Then, the control unit 24 sets a control amount according to the phase value set for each channel, and then sends a braking pressure control signal according to the control amount to the first to third valve units 20.2). 23 respectively. As a result, the first to third valve units 20, 2)
．． Front wheel branch braking pressure line 19a on the downstream side of 23
, 19b and branch braking pressure lines 22a, 22b for rear wheels.
The braking pressure can be increased or decreased, or maintained at the pressure level after the increase or decrease.

Specifically, the estimation process of the road surface friction coefficient is performed by e.g.
The process is performed as follows according to the flowchart in the figure.

tt In other words, the control unit 24 reads various data using the stem S1, and then controls the ABS using the stem S2.
It is determined whether the flag FABS is set to 1 or not. In other words, it is determined whether ABS control is in progress. This ABS flag F ABS is, for example, the opening/link flag F LOKl+ of the first to third channels.
F LOK2. Set to 1 when any of F LOK3 is set to 1, and brake switch 2 is set to 1.
0 when 5 changes from ON to OFF state, etc.
It is now reset to . Then, the control unit 24 controls the ABS flag F AB! When it is determined that l is not set to 1, step S3
, and select 3, which indicates a high friction road surface, as the friction coefficient value MU.

Further, the control unit 24 performs the step S2 described above.
When it is determined that the ABS flag FA[lS is set to 1, that is, when it is determined that ABS control is being performed, the process proceeds to step S4, and it is determined whether the deceleration DW during the previous cycle is smaller than 120G. At the same time, Y
When it is determined to be ES, the process proceeds to step S5, and it is also determined whether the acceleration AW during the previous cycle is larger than IOG, and when it is determined to be No, step S6 is executed and the middle rod coefficient value MU is set to low friction. Set 1 to indicate the road surface.

On the other hand, the control unit 24 performs the step S4 described above.
If it is determined that the deceleration DW is not smaller than 120G, step S5 is skipped and step S7 is determined.
Then, it is determined whether the acceleration AW is greater than 20G, and when the determination is YES, step S8 is executed and 3 is set as the friction coefficient value MU, while when the determination is No, step S9 is executed and the friction coefficient value MU is set to 3. 2, which indicates a medium friction road surface, is set as the coefficient value MU.

On the other hand, the process of calculating the pseudo vehicle speed is specifically performed as follows according to the flowchart shown in FIG.

That is, the control unit 24 performs step T1
After reading various data in step T2, the maximum wheel speed WMX is determined from among the wheel speeds W1 to W4 indicated by the signals from the sensors 26 to 29, and in step T3
Then, the wheel speed change amount ΔWM per sampling period Δt of the wheel speed WMX is calculated.

Next, the control unit 24 executes step T4 to read out the vehicle speed correction value CVR corresponding to the center bar coefficient value MU from the map shown in FIG.
5 to the above wheel speed change amount from this vehicle speed correction value CVR M
Determine whether MX is small. When it is determined that the wheel speed change amount △WMX is smaller than the vehicle speed correction value CVR, step T6 is executed and the value obtained by subtracting the vehicle speed correction value CVR from the previous value of the pseudo vehicle speed VR is set as the current value. replace. Therefore, the pseudo vehicle speed VB decreases at a predetermined slope according to the vehicle speed correction value cvt+.

On the other hand, the control unit 24 performs the steps T,
When it is determined that the wheel speed change amount △WMx is larger than the vehicle body speed correction value CVR, that is, the maximum wheel speed WM
When × indicates an excessive change, the process moves to step T7, and the predetermined value V is the value obtained by subtracting the maximum wheel speed WMX from the pseudo vehicle speed ~rR. Determine whether the value is greater than or not. In other words, it is determined whether there is a large difference between the maximum wheel speed WMx and the pseudo vehicle speed V. If there is no large difference, step T6 is executed to replace the current value with the value obtained by subtracting the vehicle speed correction value CVR from the same previous value of the pseudo vehicle speed V.

The control unit 24 also controls the maximum wheel speed WMX.
When a large difference occurs between the maximum wheel speed WMX and the pseudo vehicle speed VR, step T8 is executed to replace the maximum wheel speed WMX with the pseudo vehicle speed V.

In this way, the pseudo body speed 8 of the vehicle is updated every sunblink period Δt according to each wheel speed W1 to W4.

Then, the initial rapid pressure increase time TP, which is a characteristic part of the present invention,
The setting process for the first channel, for example, is performed as follows according to the flowchart of FIG.

In other words, the control unit 24 performs step U1.
After reading various data, ABS is set in step U2.
Determine whether the flag F ABS is 1 or not, and set the flag F A
When BS is set to 1, the process proceeds to step U3, where it is determined whether it is phase (3) or not. When it is determined that it is phase (2), the process proceeds to step U4 and it is determined whether or not it is the first phase (2). This is the continuation flag F C
The determination will be made based on the value of ON+.

When the control unit 24 determines that it is the first phase ■ in step U4, the control unit 24 performs step U5.
By executing the following, the initial surge pressure time Tpz for the second cycle is calculated using the pressure increase time setting function f (t5) for the second cycle, which is preset with the timer value t5 indicating the duration of phase V as a parameter. do. Here, the pressure increase time setting function f(ts) for the second cycle is as follows:
As shown in FIG. 6, the timer value t is set to decrease in stages as it increases, and therefore, when the duration of phase V in the first cycle is short, The set value of the initial rapid pressure increase time Tpz at the beginning of the pressure increase phase in the second cycle becomes large. Furthermore, when the duration of phase V is long, the set value of the initial surge pressure time T2□ becomes smaller.

On the other hand, the control unit 24 performs the step U4 described above.
When it is determined that it is not the first phase ■, that is, when it is determined that the previous cycle is not the first cycle, step U6 is executed to determine whether the wheel acceleration AW is larger than a predetermined value α0. Then, the acceleration AW is a predetermined value α. If it is determined that the acceleration is larger than that, step U7 is executed to set the value obtained by adding the predetermined value T1 to the previous value of the initial surge pressure time Tpz as the current value of the initial surge pressure time TPz, while setting the acceleration AW to the predetermined value α0.
When it is determined that the initial surge pressure time TPz is not greater than the previous value, step U8 is executed to set the value obtained by subtracting the predetermined value T2 from the previous value of the initial surge pressure time TPz as the current value of the initial surge pressure time TP2.

Therefore, at the time of transition between each cycle after the second cycle, the initial surge pressure time Tpz is corrected to largely reflect the behavior of the wheel 1 immediately after the previous surge pressure.

Note that the initial rapid pressure increase time is similarly determined for the second and third channels.

Next, the operation of this embodiment will be explained using ABS control for the first channel as an example.

That is, in the ABS non-control state during deceleration, the master cylinder 18 is activated by depressing the brake pedal 16.
The braking pressure generated in
As shown in (a) of the figure, when the amount of change in the wheel speed Wl of the left front wheel 1, that is, the deceleration DW reaches 13G, the lock flag FL in the first channel is
OKI is set to 1, and ABS control is started from time t. In the first cycle immediately after the start of this control, since the friction coefficient value MU is set to 3 indicating a high friction road surface as described above, the control unit 24 sets various control threshold values corresponding to the high friction road surface. You will have to set it.

Then, the control unit 24 controls the wheel speed W,
The slip rate S, deceleration DW, and acceleration AW calculated from the above are compared with the various control threshold values described above. In this case, assuming that the initial slip rate threshold B1 is set to 90%, for example, when the slip rate S indicates 96%, the control unit 24 sets the phase value P1 to O, as shown in FIG. Change from 2 to 2. Therefore, the braking pressure is maintained at the level immediately after the pressure increase, as shown in FIG. 2(e). For example, the slip rate S is 9
When it drops below 0%, the control unit 24
changes the phase value P1 from 2 to 3. This results in
The relief valve 20b of the first valve unit 20 is 0N10FF according to a predetermined duty rate, and as shown in FIG. As the braking force gradually decreases, the rotational force of the front wheels 1 begins to recover.

When the braking pressure continues to decrease and the deceleration DW and acceleration AW determined from the wheel speed W1 of the front wheels 1 reach O, the control unit 24 changes the phase value P1 from 3 to 5. Therefore, as shown in FIG. 4(e), the time t. Therefore, the braking pressure will be maintained at the level after pressure reduction.

Then, the state of phase V continues and the slip rate S becomes 90.
%, the control unit 24 sets a continuation flag F as shown in FIG. Set ON+ to 1. This allows the ABS in the first channel to
Control will shift to the second cycle from the time td. In that case, the control unit 24 forcibly changes the phase value P1 to 1.

Immediately after the transition to phase (2), the on-off valve 20b of the first valve unit 20 operates according to the initial surge pressure time Tpz, which is set based on the duration of phase V in the first cycle, as described above. Since the valve is opened and closed at a duty rate of 100%, the braking pressure is increased at a steep gradient as shown in FIG. 2(e). Moreover, after the initial pressure increase time TP□ ends, the on-off valve 20a
is set to 0N10FF according to a predetermined duty rate, and the braking pressure gradually increases according to a gentler slope than the above-mentioned slope.

On the other hand, in the second and subsequent cycles, as shown in the flowchart of FIG. 2, an appropriate friction coefficient value MU is determined according to the deceleration DW, acceleration AW, etc. in the previous cycle, and these friction coefficient values MU Since the control threshold value is selected according to the vehicle speed, the braking pressure is precisely controlled according to the driving condition.

Then, in the state of phase V in the second cycle, the control unit 24 controls, for example, the slip rate S.
When it is determined that B5□ is larger than the 5-1 slip rate threshold value B5□, one phase value is set to 1 and the process moves to the third cycle. At that time, the initial surge pressure time Tpz in phase r of the third cycle is set, but as described above, this initial surge pressure time Tpz is the initial surge pressure time Tpz in phase I of the second cycle. T
It is calculated based on the value of acceleration AW at time te when pz ends.

That is, as shown in FIG. 8(e), if the set value of the initial pressure increase time TP2 in the phase f immediately after the start of the second cycle is T3, the first valve unit 2
The on-off valve 20a at 0 is as shown in FIG.
The brake is kept in the ON state for a period of time corresponding to the set value T, and the braking pressure rises rapidly. As shown in (a), at time te after the elapse of the set value T, the wheel speed W1 reaches the predetermined value, as shown in (a) of the figure. When the acceleration exceeds , it means that the surge pressure amount is insufficient.

Therefore, the control unit 71-24 sets a value (Tb) obtained by adding a predetermined value T1 to the above set value as the initial rapid pressure increase time Tpz for the third cycle. As a result, the pressure surge time immediately after the start of the third cycle becomes longer than the previous time, and the shortage of braking pressure is resolved.

On the other hand, as shown by the broken line in FIG. 8(a), the above time td
When the wheel speed W1 at 1 indicates an acceleration smaller than the predetermined value α0, the sudden pressure increase amount is too large. Therefore, the control unit 24 controls the set value T
The value (Tb') obtained by subtracting the predetermined value T2 from , is set as the initial rapid pressure increase time Tp□ for the third cycle. As a result, the rapid pressure increase time immediately after the start of the third cycle is shortened compared to the previous time, and the excessive braking pressure is quickly eliminated.

Note that the phase may change from the face ■ to the phase ■ depending on the deceleration DW.

(Effects of the Invention) As described above, according to the anti-skid brake device for a vehicle according to the present invention, the next initial surge pressure amount is set based on the acceleration/deceleration of the wheels immediately after the surge pressure in the previous cycle. Even when conditions change, the braking pressure is controlled with good responsiveness, resulting in good transient response.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall schematic configuration diagram of a vehicle equipped with an anti-skid brake device according to the present invention, and FIG. 2 is a flowchart showing a process for estimating the road surface friction coefficient. , FIG. 3 is a flowchart showing the pseudo vehicle speed calculation process, FIG. 4 is an explanatory diagram of a map used in the calculation process, FIG. 5 is a flowchart showing the initial surge pressure time setting process, and FIG. 6 is a flowchart showing the process for setting the initial surge pressure time. Explanatory diagram of functions used in processing, 7th. FIG. 8 is a time chart showing the operation of this embodiment. 1.2...Front wheel, 3,4...Rear wheel, 20.2)゜2
3...Valve unit (hydraulic adjustment means), 24...Control unit (control means, wheel acceleration/deceleration calculation means, initial surge pressure amount setting means), 26-3...Wheel speed sensor (wheel speed detection means) ). Stop Mengyo

Claims (2)

[Claims] (1) A wheel speed detection means for detecting the rotational speed of the wheels, a hydraulic pressure adjustment means for adjusting the brake oil pressure, and a pressure increase phase for increasing the brake oil pressure based on the wheel speed detected by the wheel speed detection means during braking. an anti-skid brake for a vehicle, comprising a control means for operating the hydraulic pressure adjusting means so that the pressure increases and decreases periodically according to a cycle including a pressure reduction phase and a holding phase after pressure reduction, and increases rapidly at the beginning of the pressure increase phase. A device comprising: a wheel acceleration/deceleration calculation means for calculating wheel acceleration/deceleration based on the wheel speed detected by the wheel speed detection means; and an acceleration/deceleration calculated by the acceleration/deceleration calculation means after a sudden pressure increase in a previous cycle. An anti-skid brake device for a vehicle, comprising an initial surge pressure amount setting means for setting a surge pressure amount at the beginning of the next pressure increase phase based on the following. (2) a wheel speed detection means for detecting the rotational speed of the wheels; a hydraulic pressure adjustment means for adjusting the brake oil pressure; and a pressure increase phase for increasing the brake oil pressure based on the wheel speed detected by the wheel speed detection means during braking. an anti-skid brake for a vehicle, comprising a control means for operating the hydraulic pressure adjusting means so that the pressure increases and decreases periodically according to a cycle including a pressure reduction phase and a holding phase after pressure reduction, and increases rapidly at the beginning of the pressure increase phase. The apparatus includes a wheel acceleration/deceleration calculation means for calculating wheel acceleration/deceleration based on the wheel speed detected by the wheel speed detection means, and a wheel acceleration/deceleration calculation means for calculating the acceleration/deceleration of the wheel based on the wheel speed detected by the wheel speed detection means; and an initial surge pressure amount setting means for setting an initial surge pressure amount such that the larger the acceleration of the wheel, the larger the surge pressure amount at the beginning of the next pressure increase phase. Brake device.