JP3153545B2 - Anti-skid brake system for vehicles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an anti-skid brake device for suppressing excessive braking force during braking of a vehicle, and more particularly to a brake hydraulic pressure based on a wheel speed detected by a wheel speed sensor. The present invention relates to an anti-skid brake device for a vehicle, which periodically controls increase and decrease.

2. Description of the Related Art A vehicle brake system may be equipped with an anti-skid brake device for the purpose of preventing a locked or skid state of a wheel during braking.

Generally, this kind of anti-skid brake device includes a wheel speed sensor that detects the rotation speed of the wheel, and an electromagnetic control valve that adjusts the brake oil pressure, for example, a deceleration obtained from the wheel speed detected by the wheel speed sensor. When the vehicle speed falls below a predetermined deceleration, the brake pressure is reduced by controlling the pressure of the electromagnetic control valve, and the rotation speed of the wheel is recovered by the reduction of the braking pressure. When the acceleration reaches a predetermined value, the pressure of the control valve is controlled to increase to increase the braking pressure. Then, such a series of control of the braking pressure (hereinafter, AB
S) is continued until the vehicle stops, for example, to prevent the wheels from being locked or skid during sudden braking, and to stop the vehicle at a short braking distance without losing directional stability. It is possible to do.

By the way, in this type of ABS control, the speed at which the braking pressure is increased after the pressure reduction is very important. In other words, if the pressure increasing speed is reduced, the time until the next braking force acts on the wheels becomes longer, and the braking performance is reduced. Conversely, if the pressure increase speed is set too high, the braking pressure will rise beyond the appropriate value due to the inertia of the brake oil even if the pressure increase control is stopped, and excessive braking force will act on the wheels. This causes another problem.

To deal with such a problem, for example, Japanese Patent Publication No. 57-4544 discloses that in such an anti-skid brake device, the braking pressure is rapidly increased with a large pressure gradient at the beginning of the pressure increasing phase, and then the braking pressure is increased. A configuration is shown in which the pressure is increased with a small pressure gradient and the time of the rapid pressure increase is set depending on the rapid pressure increase amount in the preceding cycle.
According to this, since the braking pressure is rapidly increased at the beginning of the pressure increasing phase, good control responsiveness can be obtained. It is easy to manage the pressure increase limit, and good control accuracy is expected.

(Problems to be solved by the invention) However, in the prior art described in the above publication,
When shifting from the first cycle immediately after the start of the control in which the rapid pressure increase is not performed to the second cycle, for example, a rapid pressure increase for a certain time is performed at the beginning of the pressure increase phase. Therefore, for example, although the road surface friction coefficient is small, the rapid pressure increase time becomes long, and an excessive braking force acts on the wheels to give an uncomfortable shock to the occupant. , The braking performance is reduced due to insufficient braking pressure, and various inconveniences may occur.

Moreover, even during the ABS control, the behavior of the wheels immediately after the previous rapid pressure increase is not reflected in the next rapid pressure increase time,
Therefore, there remains a problem to be solved in terms of transient responsiveness when the road surface condition changes.

Therefore, an object of the present invention is to further improve the control performance in view of the above-described circumstances in an anti-skid brake device in which the pressure is rapidly increased in the initial stage of pressure increase.

(Means for Solving the Problems) That is, an anti-skid brake device for a vehicle according to the invention of claim 1 of the present application (hereinafter, referred to as a first invention) includes: a wheel speed detection unit that detects a rotation speed of a wheel; Hydraulic pressure adjusting means for adjusting the hydraulic pressure, and based on the wheel speed detected by the wheel detecting means at the time of braking, the brake hydraulic pressure is periodically increased and decreased according to a cycle including a pressure increasing phase, a pressure reducing phase, a holding phase after the pressure reduction, And control means for operating the hydraulic pressure adjusting means so as to rapidly increase the pressure in the early stage of the pressure increase phase, wherein a determination means for determining a shift from the first cycle to the second cycle immediately after the start of the control; When the shift to the second cycle is determined by the determination means, the pressure increase based on the duration of the holding phase after the pressure reduction in the first cycle. Initial rapid pressure increase time setting means for setting a rapid pressure increase time at the beginning of a phase is provided.

Further, an anti-skid brake device for a vehicle according to the invention of claim 2 of the present application (hereinafter, referred to as a second invention) includes a wheel speed detection unit that detects a rotation speed of a wheel, a hydraulic pressure adjustment unit that adjusts a brake hydraulic pressure, Based on the wheel speed detected by the wheel speed detecting means at the time of braking, the brake hydraulic pressure is periodically increased and decreased according to a cycle including a pressure increasing phase, a pressure decreasing phase, a holding phase after the pressure decreasing, and at the beginning of the pressure increasing phase. In a configuration including control means for operating the hydraulic pressure adjusting means so as to rapidly increase the pressure, a first determination means for determining a shift from the first cycle to a second cycle immediately after the start of the control, and The second determination means for determining the shift of the pressure and the first determination means determines that the shift to the second cycle has occurred. In addition to setting the rapid pressure increase time at the beginning of the pressure increase phase based on the duration of the phase, when the transition between the respective cycles is determined by the second determination means, the duration in the holding phase after the pressure reduction in the previous cycle is An initial rapid pressure increase time setting means for setting the rapid pressure increase time based on the pressure decrease execution time in the pressure decrease phase is provided.

(Operation) According to the first and second aspects of the invention, when transitioning from the first cycle to the second cycle immediately after the start of control that is not performed for rapid pressure increase, the duration of the holding phase after the pressure reduction in the first cycle , The rapid pressure increase time at the beginning of the pressure increase phase is set, so that an appropriate braking pressure corresponding to the road surface condition is obtained, and the initial control performance is improved.

Further, according to the second invention, at the time of transition between the respective cycles after the second cycle, the duration of the holding phase after the pressure reduction in the previous cycle and the pressure reduction execution time in the pressure reduction phase determine the initial time of the next pressure increase phase. Since the rapid pressure increase time is set, the next initial rapid pressure increase time is set according to the actual behavior of the wheel after the previous rapid pressure increase, and good transient response is obtained. Will be.

(Examples) Hereinafter, examples of the present invention will be described.

As shown in FIG. 1, in the vehicle according to this embodiment, left and right front wheels 1 and 2 are driven wheels, left and right rear wheels 3 and 4 are driving wheels, and the output torque of the engine 5 is The power is transmitted to the left and right rear wheels 3 and 4 via the propeller shaft 7, the differential device 8 and the left and right drive shafts 9 and 10.

Each of the wheels 1 to 4 has these wheels 1 to 4
Brake devices 11 to 14 configured by discs 11a to 14a that rotate integrally with them and calipers 11b to 14b that brake the rotation of these disks 11a to 14a by receiving a supply of braking pressure.
Are provided, and a brake control system 15 for performing a braking operation of these brake devices 11 to 14 is provided.

The brake control system 15 includes a booster 17 that increases the depression force of a brake pedal 16 by a driver, and a master cylinder 18 that generates a braking pressure according to the depression force increased by the booster 17. . The front-wheel braking pressure supply line 19 led from the master cylinder 18 is branched into two paths, and these front-wheel branch braking pressure lines 19a, 19b are connected to the brake devices 1 in the left and right front wheels 1, 2.
One of the front-branch braking pressure lines 19a, which is connected to the calipers 11a and 12a of the left and right front wheels 1, and communicates with the brake device 11 of the left front wheel 1, has an electromagnetic on-off valve 20a and an electromagnetic relief valve. First valve unit 2 comprising valve 20b
0, and the other front wheel branch braking pressure line 19b communicating with the brake device 12 of the right front wheel 2 is also provided with an electromagnetic opening / closing valve 21a and an electromagnetic relief valve similarly to the first valve unit 20. The second valve unit 2 including the valve 21b
1 is installed.

On the other hand, the first and second valve units are connected to the rear wheel braking pressure supply line 22 led from the master cylinder 18.
Similarly to 20, 21, a third valve unit 23 including an electromagnetic on-off valve 23a and an electromagnetic relief valve 23b is installed, and the rear wheel braking pressure supply line 22 is
Downstream of the third valve unit 23, the path is branched into two paths, and these rear wheel branch braking pressure lines 22a, 22b are provided with calipers 13b, 14b of the brake devices 13, 14 in the left and right rear wheels 3, 4.
Connected to each other. That is, the brake control system 15 in this embodiment is different from the first valve unit in the first embodiment.
The first channel for variably controlling the braking pressure of the brake device 11 on the left front wheel 1 by the operation of 20 and the brake device 12 for the right front wheel 2 by the operation of the second valve unit 21
And a third channel for variably controlling the braking pressure of the two brake devices 13 and 14 in the left and right rear wheels 3 and 4 by the operation of the third valve unit 23, These first to third channels are controlled independently of each other.

The first to first brake control systems 15
A control unit 24 for controlling the third channel is provided. The control unit 24 includes a brake signal from a brake switch 25 for detecting ON / OFF of the brake pedal 16 and a wheel speed sensor for detecting the rotation speed of each wheel. By inputting wheel speed signals from 26 to 29 and outputting braking pressure control signals corresponding to these signals to the first to third valve units 20, 21, and 23, respectively, the left and right front wheels are
The braking control for the slip of the rear wheels 1 and 2 and the rear wheels 3 and 4, that is, the ABS control, is performed in parallel for each of the first to third channels. That is, the control unit 24
Are based on the wheel speeds indicated by the wheel speed signals from the respective wheel speed sensors 27 to 30, based on the first to third valve units 20, 21,
On-off valves 20a, 21a, 23a and relief valves 20b, 21b, 23b in 23
Is controlled by duty control to apply a braking force to the front wheels 1 and 2 and the rear wheels 3 and 4 with a braking pressure according to a slip state. The brake oil discharged from each of the relief valves 20b, 21b, 23b in the first to third valve units 20, 21, 23 is
The master cylinder above via a drain line (not shown)
The tank is returned to the 18 reservoir tanks 18a.

In the ABS non-control state, the control unit 24 does not output the braking pressure control signal, and therefore, as shown in the drawing, the first to third valve units 20, 21, 23
The relief valves 20b, 21b, and 23b are closed and held, and the open / close valves 20a, 21a, and 23a of the units 20, 21, and 23 are held open, respectively, in accordance with the depression force of the brake pedal 16. The braking pressure generated in the master cylinder 18 is applied to the braking devices 11 to 14 on the left and right front wheels 1 and 2 and the rear wheels 3 and 4 via the front wheel braking pressure supply line 19 and the rear wheel braking pressure supply line 22. The braking force is supplied to the front wheels 1 and 2 and the rear wheels 3 and 4 and is directly applied to the braking force.

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

That is, the control unit 24
The acceleration and the deceleration for each wheel are calculated based on the wheel speed indicated by the signals from. Here, the method of calculating the acceleration or the deceleration will be described. The control unit 24 divides the difference between the current value of the wheel speed and the current value of the wheel speed by the sampling period Δt (for example, 7 ms), and converts the result to the gravitational acceleration. The converted value is updated as the current acceleration or deceleration.

Further, the control unit 24 executes a predetermined rough road determination process to determine whether or not the traveling road surface is a rough road. This rough road determination processing is executed, for example, as follows. That is,
The control unit 24 sets the bad road flag F _AKRO to 0 if the number of times the deceleration or acceleration of the rear wheels 3 and 4 exceeds a predetermined upper limit or lower limit within a predetermined time is within a set value.
If the number of times that the values indicating the acceleration and the deceleration exceed the upper limit value and the lower limit value within a certain period of time are equal to or greater than a set value, the traveling road surface is determined to be a rough road, and the rough road flag F _AKRO Is set to 1.

Then, the control unit 24 selects the rear wheels 3, 4 representing the wheel speed and acceleration / deceleration for the third channel. In the present embodiment, the smaller one of the two wheel speeds is selected as the rear wheel speed in consideration of the detection error of the two wheel speed sensors 28 and 29 of the rear wheels 3 and 4 at the time of slip, and The acceleration and the deceleration obtained from the wheel speed are selected as the rear wheel deceleration and the rear wheel acceleration.

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

The control unit 24 includes the wheel speed sensors 28, 29
Slip ratios for the first to third channels from the rear wheel speeds obtained from the signals from the vehicle and the wheel speeds of the left and right front wheels 1 and 2 indicated by the signals from the wheel speed sensors 26 and 27 and the pseudo vehicle speed. In this case, the slip ratio is calculated using the following relational expression: Slip ratio = [(pseudo vehicle speed−wheel speed) / pseudo vehicle speed] × 100. That is, as the deviation of the wheel speed from the pseudo vehicle speed increases, the slip ratio increases, and the slip tendency of the wheel increases.

Subsequently, the control unit sets various control thresholds used for controlling the first to third channels.

Here, an outline of the control threshold setting process will be described. The control threshold setting process is performed, for example, as follows. That is, the control unit 24 in advance from the vehicle speed range and the road surface friction coefficient and the various control threshold which is set in accordance with, the select control threshold corresponding to the friction coefficient value MU and the pseudo vehicle body speed V _R, these control The threshold value is corrected according to the determination result of the above-described rough road determination processing. Here, as the control threshold, shown for example 2-0 deceleration threshold value B ₀₂ for shift determination from phase 0 showing the ABS non-control state to phase II showing a holding state of increasing After depressurization, the pressure increasing state phase 1-2 deceleration threshold B for determining the transition from I to the phase II
₁₂ and phase III showing the decompression state from the above phase II
2-3 deceleration threshold value B ₂₃ for shift determination to a 3-5 deceleration threshold value B ₃₅ for shift determination to phase V showing a holding state after decompression from this phase III, phase from phase V I A 5-1 slip ratio threshold value B _SZ for determining pressure increase to
Initial slip ratio threshold B ₁ for the first cycle immediately after the start of control
Are set in accordance with the vehicle speed range and the road surface friction coefficient, respectively. In this case, the deceleration threshold value that greatly affects the braking force is determined by adjusting the friction coefficient value MU to achieve a high level of both the braking performance when the road surface friction coefficient is large and the control responsiveness when the road surface friction coefficient is small. The lower the level, that is, the lower the road surface friction coefficient, the closer to 0G. The minimum value of the friction coefficient values of the first to third channels is used as the friction coefficient value MU.

In addition, the control threshold value is similarly set for the second and third channels.

Then, the control unit 24 performs a lock determination process for each channel and the first to third valve units.
A phase determination process for defining the control amounts for 20, 21, and 23 and a cascade determination process are performed.

Here, the lock determination processing will be roughly described as follows. For example, in the lock determination process for the first channel for the left front wheel, the control unit 24 firstly sets the continuation flag F for the first channel.
This value _CON1 the on has been set as the previous value, then the pseudo vehicle body speed V _R and the wheel speed W ₁ and a predetermined condition (e.g., V _R <5 Km /
H, W ₁ <2.5 km / H) is determined, and when these conditions are satisfied, the continuation flag F _CON1 and the lock flag F _LOK1 are each reset to 0. It is determined whether the lock flag _FLOK1 is set to "1". If the lock flag F _LOK1 is not set to 1 under a predetermined condition (for example,
V _R is set to 1 to the lock flag F _LOK1 when larger wheel speed W _1).

On the other hand, the control unit 24
_{When LOK1} is determined to be set to 1 indicates for example phase value P ₁ is phase V of the first channel 5
_Is set to 1 and the continuation flag F _CON1 is set to 1 when the slip ratio S ₁ is smaller than 10%.

Note that the lock determination process is similarly performed on the second and third channels.

To explain the outline of the phase determination processing, 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 the slip rate. Phase 0, Phase I indicating a pressure increase state during ABS control, Phase II indicating a holding state after pressure increase, Phase III indicating a pressure reduction state, Phase IV indicating a rapid pressure reduction state, and Phase V indicating a holding state after pressure reduction. Is to be selected.

Further, the cascade determination process determines the cascade lock state in which the wheel lock state occurs continuously in a short time because the wheel is easily locked even with a small braking pressure, particularly on a low friction road surface such as an ice burn. The cascade flag _FCAS is set to 1 when a predetermined condition in which the cascade lock is likely to occur is satisfied.

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, 21, 23. Is output for each. As a result, the braking pressure of the front-wheel branch braking pressure lines 19a, 19b and the rear-wheel branch braking pressure lines 22a, 22b downstream of the first to third valve units 20, 21, 23 increases or decreases. , Or maintained at a pressure level after pressure increase or pressure reduction.

The process of estimating the road surface friction coefficient is specifically performed as follows, for example, according to the flowchart of FIG.

That is, the control unit 24 in terms of reading the various data in step S _1, ABS flag F in step S ₂
It is determined whether _ABS is set to 1. That is, it is determined whether the ABS control is being performed. The ABS flag F _ABS is set to 1, for example, when any of the lock flags _FLOK1 , _FLOK2 , _FLOK3 of the first to third channels is set to 1, and when the brake switch 25 is turned ON.
It is reset to 0 when it is switched to the OFF state. And control unit 24
, When the ABS flag F _ABS is determined not to be set to 1, set the 3 showing the high friction surface as a friction coefficient value MU proceeds to step S _3.

Further, the control unit 24, when it is determined that in step S ₂ is ABS flag F _ABS is set to 1, that is, when it is determined that the ABS control is deceleration DW of a cycle during the previous routine proceeds to step S ₄ There together to determine whether -20G smaller than acceleration AW of same during the previous cycle proceeds to step S ₅ when it is determined that YES is 10
On which to determine G greater than or not, is set to 1 indicating a low friction surface to Step S ₆ as a friction coefficient value MU running when it is determined that the NO.

On the other hand, the control unit 24, when the deceleration DW in step S ₄ is determined to not smaller than -20G, the sequence proceeds to the step S ₇ skips step S _5, determines whether the acceleration AW is larger than 20G and, while set 3 as the friction coefficient value MU executes step S ₈ when the result of determination is YES, the set of 2 indicating a medium friction surface as a friction coefficient value MU executes step S ₉ when it is determined that the NO I do.

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

That is, the control unit 24, in terms of reading the various data in step T _1, the sensor in step T ₂
With the signal to determine the highest wheel speed W _MX out of the wheel speed W ₁ to _W-4 showing from 26 to 29, the wheel speed change amount per sampling period △ t of the wheel speed W _MX Step T ₃ △ W Calculate _MX .

Then, the control unit 24 reads the vehicle speed correction value C _VR corresponding from the map shown in FIG. 4 executes step T ₄ to the friction coefficient value MU, are the wheel speed change amount [Delta] W _MX Step T ₅ It is determined whether or not the vehicle speed correction value _{CVR is} equal to or less than CVR. Then, the value wheel speed change amount △ W _MX is when it is determined that less than the vehicle speed correction value C _VR is obtained by subtracting the vehicle speed correction value C _VR from the previous value of the pseudo vehicle body speed V _R by performing the steps T ₆ Is replaced with the current value. Therefore, the pseudo vehicle body speed V _R becomes possible to decrease at a predetermined gradient in accordance with the vehicle speed correction value C _VR.

On the other hand, the control unit 24, when the wheel speed change amount △ W _MX is judged greater than the vehicle speed correction value C _VR in step T _5, that is, when the maximum wheel speed W _MX showed excessive change, step pseudo vehicle body speed moved to T ₇
The value obtained by subtracting the maximum wheel speed W _MX from V _R is determined whether or not a predetermined value greater than or equal _to V _0. In other words, the maximum wheel speed W _MX and the pseudo vehicle speed V _R
It is determined whether or not there is a large gap between them. And if there is no big difference, the above steps
Running T ₆ replaces the value obtained by subtracting the vehicle speed correction value C _VR from the previous value of the pseudo vehicle body speed V _R to the current value.

Further, the control unit 24, when a large gap occurs between the highest wheel speed W _MX and the pseudo vehicle body speed V _R replaces the highest wheel speed W _MX pseudo vehicle body speed V _R by performing the steps T _8.

In this way, the pseudo vehicle body speed V _R of the vehicle wheel speeds
It is updated every sampling period Δt according to W _{1 to} W ₄ .

Then, the initial rapid pressure increase time T _PZ which is a characteristic part of the present invention.
Is performed as follows according to the flowchart of FIG. 5 for the first channel, for example.

That is, the control unit 24, in terms of reading the various data in step U _1, ABS flag F in Step U _2
ABS is determined whether 1, when the flag F _ABS is set to 1, determines whether the phase I proceeds to step U _3. When it is determined that the Phase I, determines whether the first phase I proceeds to step U _4. This is determined based on the value of the continuation flag F _CON1 .

Control unit 24, when it is determined that the initial Phase I in step U ₄ executes the step U _5, the second cycle up for a preset timer value t ₅ indicating the duration of the phase V as a parameter using pressure boosting period setting function f (t _5), calculates the inter initial surge pressure time T _PZ for the second cycle. Here, the second cycle pressure increase time setting function f (t ₅ ) is set so as to decrease stepwise as the timer value t ₅ increases, as shown in FIG. and thus when the duration of the phase V in the first cycle is short, the set value of the pressure increase phase early initial pressure increase between T _PZ is increased in the second cycle accordingly. Further, when the duration of the phase V is long, the set value of the initial surge pressure boosting period T _PZ becomes smaller reversed.

On the other hand, the control unit 24, when it is determined that it is not a first Phase I in step U ₄ is
Timer value t ₅ indicating the duration of phase V during the previous cycle
The first normal pressure increase time setting function g ₁ (t ₅ ), which is set in advance as a parameter, and the second normal pressure increase time setting function, in which the pressure reduction execution time t _DG in the previous cycle is set in advance as a parameter
g ₂ (t _DG ) is used to calculate the initial rapid pressure increase time T _PZ of the next cycle (step U ₆ ). Here, the first normal pressure increase time setting function g ₁ (t ₅ ) is, for example, the seventh as shown in the figure, along with the timer value t ₅ indicating the duration of the phase V is even set to 0 when 0 is set so as to decrease stepwise in the negative direction as the timer value t ₅ increases ing. Further, the second normal pressure increasing time setting function g ₂ (t _DG ) is, for example, as shown in FIG. 8, a pressure reducing execution in which the duty ON time of the relief valve 20b of the first valve unit 20 in the first channel is integrated. It is set to be a positive predetermined value when the time _tDG is larger than the predetermined value.

Therefore, at the time of transition between the second and subsequent cycles, the first and second pressure increasing time setting functions g ₁ (t ₅ ) and g ₂
Various initial rapid pressure increase times T _PZ corresponding to (t _DG ) will be set.

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

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

That is, in the ABS non-control state at the time of deceleration, the brake pressure generated in the master cylinder 18 is gradually increased by the depression operation of the brake pedal 16, and for example, as shown in FIG. the amount of change W _1, i.e., when the deceleration DW reaches -3G, as shown in FIG. 6 (a), the lock flag F _LOK1 in the first channel is set to 1, the ABS control from the time t _a Will be migrated. In the first cycle immediately after the start of this control, since the friction coefficient value MU is set to 3 indicating the high friction road surface as described above, the control unit 24 sets various control threshold values corresponding to the high friction road surface. Will be set.

Then, the control unit 24 compares the slip ratio was calculated from the wheel speed W ₁ S, deceleration DW, the acceleration AW and the various control threshold. In this case, when the initial slip ratio threshold value B ₁ is being set for example to 10%, when indicated slip ratio, for example 4%, the control unit 24, as shown in FIG. 2 (d), phase value P ₁ To 0
From 2 to 2. Therefore, the braking pressure is as shown in FIG.
As shown in (2), the pressure is maintained at the level immediately after the pressure increase. Then, for example, when the slip ratio S is greater than 10%, the control unit 24 sets the phase value P ₁
Is changed from 2 to 3. As a result, the relief valve 20b of the first valve unit 20 is turned ON / OFF according to the predetermined duty ratio.
As a result, as shown in FIG. _9E , the braking pressure gradually decreases from the time tb according to a predetermined gradient, and the braking force gradually decreases. Rotation starts to recover.

Further deceleration DW and acceleration AW reduced pressure was determined from the wheel speed W ₁ of the front wheel 1 Following the braking pressure when it becomes 0, respectively, the control unit 24 changes the phase value P ₁ from 3 to 5. Therefore, as shown in FIG.
So that the brake pressure from the time t _c is maintained at the level of post-vacuum.

Then, the state of the phase V continues and the slip ratio S becomes 10
%, The control unit 24
As shown in FIG. 3B, the continuation flag F _CON1 is set to 1. Thus, ABS control in the first channel will be migrated from the time t _d in the second cycle. In this case, the control unit 24 forcibly changes the phase value P1 to ₁ . Immediately after the transition to the phase I, the opening / closing valve 20b of the first valve unit 20 responds to the initial rapid pressure increase time T _PZ set based on the duration of the phase V in the first cycle as described above. As a result, the braking pressure is increased at a steep gradient as shown in FIG. Also, the initial pressure increase time T _PZ
Is completed, the on-off valve 20a is turned on / off in accordance with a predetermined duty ratio, and the braking pressure gradually increases according to a gradient that is gentler than the above gradient.

On the other hand, after the second cycle, as shown in the flowchart of FIG. 2, an appropriate friction coefficient value MU is determined according to the deceleration DW and acceleration AW in the previous cycle, and these friction coefficient values MU are determined. Is selected, so that precise control of the braking pressure according to the traveling state is performed.

Then, in the state of phase V in the second cycle, the control unit 24
Is smaller than the 5-1 slip ratio threshold B _SZ , the phase value P ₁ is set to 1 and the process shifts to the third cycle. Then, At this time, the initial surge pressure boosting period T _PZ in Phase I of the third cycle is being set, the initial pressure increase between T _PZ is a duration t ₅ phases V in the second cycle, Since it is calculated based on the pressure reduction execution time _tDG in the phase III, the value appropriately reflects the behavior of the front wheel 1 after the rapid pressure increase in the second cycle.

In some cases, the phase may be switched from phase V to phase I depending on the degree of subtraction DW.

(Effects of the Invention) As described above, according to the anti-skid brake device for a vehicle according to the present invention, when shifting from the first cycle immediately after the start of control in which rapid pressure increase is not performed to the second cycle, the first cycle is performed.
Since the rapid pressure increase time is set based on the duration of the holding phase after the pressure reduction in the cycle, an appropriate braking pressure corresponding to the road surface condition is obtained, and the initial control performance is improved.

Further, according to the second invention, at the time of transition between the respective cycles after the second cycle, the rapid pressure increase at the beginning of the pressure increase phase is performed by the duration of the holding phase after the pressure reduction in the previous cycle and the pressure reduction execution time in the pressure reduction phase. Since the time is set, the next initial rapid pressure increase time is set according to the actual behavior of the wheel after the previous rapid pressure increase, and good transient response is obtained. Become.

[Brief description of the drawings]

FIG. 1 shows an embodiment according to the present invention. FIG. 1 is an overall schematic configuration diagram of a vehicle equipped with an anti-skid brake device according to the present invention, FIG. 2 is a flowchart of friction coefficient estimation processing, FIG. FIG. 4 is a flowchart showing a 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 an initial rapid pressure increase time setting process, and FIGS. FIG. 9 is an explanatory diagram of a function used in the processing, and FIG. 9 is a time chart showing the operation of the present embodiment. 1,2 ... front wheel, 3,4 ... rear wheel, 20, 21, 23 ... valve unit (hydraulic pressure adjusting means), 24 ... control unit (control means, determining means, first determining means, second determining Means, initial rapid pressure increasing time setting means), 26 to 39 ... wheel speed sensors (wheel speed detecting means).

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoji Kurihara 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (56) References JP-A-1-106676 (JP, A) JP-A-62 -218258 (JP, A) JP-A-2-267064 (JP, A) JP-B-57-4544 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60T 8/58

Claims (2)

(57) [Claims] 1. A wheel speed detecting means for detecting a rotation speed of a wheel, a hydraulic pressure adjusting means for adjusting a brake oil pressure, and a brake oil pressure is increased based on a wheel speed detected by the wheel speed detecting means during braking. Phase, depressurization phase, to periodically increase and decrease according to a cycle including a holding phase after decompression, and to rapidly increase the pressure in the early stage of the pressure increase phase,
An anti-skid brake device for a vehicle, comprising: a control unit for operating the hydraulic pressure adjusting unit; a determining unit for determining a shift from a first cycle to a second cycle immediately after the start of control; Initial pressure increasing time setting means for setting a rapid pressure increasing time at the beginning of the pressure increasing phase based on the duration of the holding phase after the pressure reduction in the first cycle when the shift to two cycles is determined. An anti-skid brake device for a vehicle. 2. A wheel speed detecting means for detecting a rotational speed of a wheel, a hydraulic pressure adjusting means for adjusting a brake oil pressure, and a brake oil pressure is increased based on the wheel speed detected by the wheel speed detecting means during braking. Phase, depressurization phase, to periodically increase and decrease according to a cycle including a holding phase after decompression, and to rapidly increase the pressure in the early stage of the pressure increase phase,
An anti-skid brake device for a vehicle, comprising: a control unit for operating the hydraulic pressure adjusting unit, wherein the first determination unit determines a transition from a first cycle to a second cycle immediately after the control is started; A second determining means for determining a transition between cycles, and a second determining means
When the transition to the cycle is determined, the rapid pressure increase time at the beginning of the pressure increase phase is set based on the duration of the holding phase after the pressure reduction in the first cycle, and the transition between the cycles is determined by the second determination means. When it is determined, an initial rapid pressure increase time setting means for setting the rapid pressure increase time based on the duration in the holding phase after the pressure reduction in the previous cycle and the pressure reduction execution time in the pressure reduction phase is provided. Anti-skid brake device for vehicles.