JPH01273758A - Anti-skid controller - Google Patents

Abstract

PURPOSE:To secure high braking efficiency and operational stability by determining the time from the start of controlling to the start of anti-skid and reducing pressure slowly when it is long and rapidly when it is short. CONSTITUTION:The time of a variable timer 42a becomes H only while the output QA of the first timer 50 responds to the peak value alphamax of the acceleration of wheels from the moment when the acceleration of wheels becomes below the reference value and the output of a comparator 34a goes down, and the output of the second timer 51 outputs to an AND gate 41a for a fixed hime H from the moment when the output QA goes down. That is, when the time from the start of braking to the start of anti-skid having been determined by the variable timer 42a is long, i.e., when a vehicle is running on a road surface having high friction coefficient, the pressure of brake fluid is reduced by a pressure reducing speed control means slowly, and when short, i.e., on a road surface having low friction coefficient, the pressure is reduced rapidly. Thus, high braking efficiency and operational stability can be secured on both road surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an anti-skid control device that prevents wheel locking during braking in a manner that achieves maximum braking efficiency.

(Prior art) An anti-skid control device is an anti-skid control device that automatically controls the speed of a wheel when a predetermined slip relationship (for example, a state in which the road surface friction coefficient of the wheel exceeds an ideal slip ratio at which it is maximum) occurs with respect to the wheel speed or vehicle body speed during braking. The brake fluid pressure is reduced to prevent slip (lock).

However, if the brake fluid pressure is reduced at a high speed, the brake fluid pressure may become too low on a high-friction road, resulting in a longer braking distance or a greater imbalance in the braking force between the wheels, resulting in unstable steering. On the other hand, if the decompression speed is slow,
If the brake fluid pressure is too high on a low-friction road, the braking distance will be longer due to slippage, which will lead to a decrease in braking efficiency. In this sense, it is preferable to reduce the rate of brake fluid pressure reduction on high friction roads, and to increase the rate of brake fluid pressure reduction on low friction roads.

For this reason, as described in Japanese Patent Application Laid-Open No. 60-261769, a pseudo vehicle speed has been calculated by imitating the vehicle speed from the wheel speed (because Doppler radar, etc. that directly detects the vehicle speed is expensive and unrealistic). A technique f4i has been proposed in which the road surface friction coefficient is judged from the decreasing slope of the road surface and the result contributes to the above-mentioned pressure reduction speed control.

(Problem to be solved by the invention) 7 However, with this technology, the slope of the aggregated vehicle speed in the second and subsequent skid cycles can be calculated (from 1, 7, it can correspond to approximately 6 road friction coefficients, but The low slope G of the vehicle speed in the skid cycle is 1° (high or low in advance because it cannot be calculated)? Since the only option is to set it to correspond to one of the friction roads, it does not necessarily correspond to the road friction coefficient, and the decompression speed control as described above cannot be obtained, resulting in a decrease in braking efficiency and unstable steering. I confirmed that there was a problem.

(Step 1 to Solve the Problem) The present invention provides a method in which the time from the start of braking to the start of inch skinning, shown as Δ1 in FIG. 10, increases as the friction increases, and this time can be detected during the first skid cycle. If this time is used to control the brake fluid pressure reduction speed, this control will be as required from the first skid cycle.
From the viewpoint that the above-mentioned problem can be solved by obtaining brake fluid pressure, when the wheel that generates brake fluid pressure is stopped during braking, there is a method to prevent wheel lock by reducing the pressure when the brake fluid pressure is generated during braking. In a device configured to perform anti-skid control, the time from the start of braking to the start of anti-skid i3 was measured.
4. When the time is long, the filtration pressure is gradually reduced, and when the time is short, the filtration pressure is reduced. The system is equipped with rapid decompression speed control means.

(Function) The anti-skid control device reduces the brake fluid pressure when the braking intermediate wheels that have fixed the pre-hydraulic pressure slips once, thereby preventing the wheels from slipping.

At about this time, the amplifier starts from the start of braking detected by the first stage of timing.
When the [, % interval until the start of skid is long, that is, on a high friction road, the pressure reduction speed control means gradually reduces the brake fluid pressure, and when the period of -1- is short, that is, on a low 1g friction road. Then, the pressure speed control stage f rapidly performs the pressure reduction described in 1-a)
Therefore, on a high friction road, 1. - It is possible to prevent the braking distance from becoming too long due to the hydraulic pressure becoming too low, or from becoming unstable due to unbalanced braking force between the wheels. Furthermore, it is possible to prevent the braking distance from becoming longer due to slip due to too high brake fluid pressure on low-friction roads, ensuring high braking efficiency and steering stability on any road surface.

Moreover, the above-mentioned time can be detected during the first skid cycle, and the above-mentioned decompression speed control and its effects can be achieved from the first skid cycle.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is an overall system diagram showing one embodiment of the anti-skid control device of the present invention, in which 1 is the right front wheel, 1a is its
, ・Eel cylinder, 2 is the left front wheel, 2a is its wheel cylinder, 3 is the right rear wheel, 3a is the wheel cylinder of A, 4 is the left rear wheel 1. 4a is the wheel cylinder, respectively. Also, 5 is the engine, 6 is the transmission, 7 is the propeller shaft, 8 is the differential gear, 9.10 is the rear axle, and the wheels that go up to these drive the two rear wheels 3 and 4.
, ψ can be run.

If play 1 is installed, connect the two master cylinder systems 110 and 11a to the right front wheel cylinder 1a through conduit 12, and connect to the left front wheel cylinder 2a through conduit 13 l-, and the other system 1. Engineering 1) to pipeline 14
The hydraulic brake system is connected to the right rear wheel cylinder 3a through the six pipes 14, 15, and to the rear wheel cylinder 4a through the six pipes 14 and 15, forming a so-called front-rear split type hydraulic brake system. This brake device is the brake pedal 16 ;? ; Occurs due to loading and causes two systems 11 of master cylinder 11
a.1. It is operated by the master cylinder hydraulic pressure output from the lb.

Three anti-skid control means are provided for the right front wheel 1, the left front wheel 2 and the rear two wheels 3.
．． 13゜Acchani ri 17a inserted in 14
, 17b, 17c, and an anti-skid control circuit 18 that controls their operation.

Active, Knee, and 1.7a, 17b, and 17c are the same, so the corresponding parts are fixed a,
Only the right front wheel actuator 17a, which is indicated by the same reference numerals 1: + and Tatsumi c, will be described in detail below. The actuator 17a has an inflow valve (EV valve H9a) and an exhaust valve (EV valve H9a).
It is constructed by connecting a V-valve 20a, a pump 21a, an accumulator 22a, and a check valve 23a as shown. The EVVf9a and the AV valve 20a receive the EV, signal and AV from the anti-skid control circuit 18,
Pumps 21a are individually controlled by signals such as pumps 21b, 2 in other actuators 17b, 17C.
It is suitably driven by a common motor 24 together with 1c, and this drive is controlled by an MR multiplied signal from an anti-skid control circuit 18.

When the EV signal is at the L level, the EVVf9a is opened, and when the AV signal is at the L level, the AV valve 20a is closed, and the brake fluid pressure to the wheel cylinder 1a is increased until it reaches the same value as the master cylinder fluid pressure. . Also, in this state E
When the EV signal changes to the H level and EVVf9a is also closed, the brake fluid pressure to the wheel cylinder la is maintained. Next, in this state, the ^vI signal changes to H level to open the AV valve 20a, and in addition, the transistor 25 is made conductive by the H level MR multiplied signal, and the motor 24 is energized by the power supply +E to drive the pump 21a. The brake fluid pressure in the wheel cylinder la is returned to the mask cylinder 11 and reduced in pressure. The above operations are summarized in the table below.

The anti-skid control circuit 18 controls the EV,
A circuit part 18a that emits signals, AV, and signals; and a circuit part that emits EV, signals, AV, and signals for the left front wheel actuator 17b based on signals from the wheel speed sensor 26b that detects the rotational speed of the left front wheel 2. 18b and rear 2 wheels 3
．． EV, signal, and AV for the rear wheel actuator 17c based on the signal from the wheel speed sensor 26c that detects the rotational speed of the propeller shaft 7, which is the average rotational speed of the propeller shaft 7.
The circuit portion 18c that emits the l signal and the pseudo vehicle speed generator 2
7, and circuits 28a, 28b, and 28 that generate a target wheel speed corresponding to the ideal slip ratio from the upcoming pseudo vehicle speed.
c and AV+', which is the source of the AV+, AVx, and AVs signals.
, AVt'1AV3' (HL/to/L/), and a retriggerable timer 30 that is triggered every time the output of the OR gate rises and generates an MR multiplied signal of H level for a predetermined period of time. Consists of.

Since the circuit portions 18a+18b and 18c have similar configurations, corresponding portions are designated by the same reference numerals with different suffixes a, b, and c, and only the circuit portion 18a will be described in detail. A wheel speed detection circuit 31a calculates the peripheral speed (wheel speed) Vw from the right front wheel rotation speed (pulse) signal from the wheel speed sensor 26a and the rotation radius of the right front wheel. This wheel speed V□ is input to the wheel acceleration detection circuit 32a and is used to calculate the wheel acceleration α, 11 (negative means deceleration). Wheel acceleration α. , are compared with the deceleration reference value and the acceleration reference value at in the comparators 33a and 34a, and the comparator 33
a outputs an H level signal when the wheel deceleration α, 4I becomes a larger deceleration than the reference value b1, and the comparator 34a outputs an H level signal when the wheel acceleration α, 11 becomes an acceleration greater than the reference value al. Output a signal. Comparator 35a indicates wheel speed Lll
The comparator 35a outputs an H level signal while the wheel speed vwl is below the target wheel speed. The OR gate 36a is the comparator 33a to 35a.
Takes the logical sum of the H level outputs and generates an H level signal,
This signal passes through an OR gate 40a and is supplied to the EV valve 19a after being amplified by an amplifier 37a as an Ev1 signal.

AND gate 38a connects the H level output of comparator 35a and
The logical product with the L level signal from the comparator 34a is taken and the H level signal is
A level AV,' signal is generated, and this signal is converted into an AV, signal by a pressure reduction speed control circuit 90a according to the gist of the present invention, and then supplied to the AV valve 20a via an amplifier 39a.

The remaining inputs of the OR gate 40a are connected to an AND gate 41a.
A variable timer 42a, a pulse generator (O5C) 43a that generates a rectangular pulse of a constant frequency, and a liver signal from the retrigger pull timer 30 are supplied to the three if A NO gates, respectively. ] Weird timer 4
2a is triggered by the falling edge of the output of the comparator 34a, and outputs the to11/bell signal for a time corresponding to the peak value αmax of the wheel acceleration α1 detected by the peak value detection circuit 44a. - Negative value detection circuit 44a
is also from the fall of the output from the comparator 33a to the next rise: the peak value α of the wheel acceleration α1,
,. 8 is detected.

Therefore, the peak value detection circuit 44a is constructed of a peak bold circuit consisting of a sofa amplifier 45, 46, a diode 47, and a capacitor 48, and an Arnaud log switch 49, as shown in FIG. Buffer amplifier 45 (input wheel acceleration α, 7
, the output signal of the comparator 33a is input to the gate t- of the analog switch 49, and the peak value α,
Suppose that it outputs □.

The operation of the peak value detection circuit 44a is based on the wheel acceleration α
, is as shown in FIG. 3, and therefore the output of the comparator 33a is as shown in the same figure. That is, while the car @ castle speed lWα□ exceeds the reference value h14' and the output of the C comparator 33a is at H level, the comparator output is A.) ~ 1 Cog switch 49 is turned on (11), recondenser 48 is reset (L), Bi-value α of wheel acceleration α□ between resets of l-. By charging the capacitor 48 with a voltage corresponding to , the buffer amplifier 46 can output the ζ beam value α□.

Further, the variable timer 42a is connected to the first timer 42a as shown in FIG.
750 and a second timer 51, the first timer 5
The input B of 0 is a comparator 34; the output of 1 is an inverter 52.
3 °C, and the first timer 5 starts at the falling edge of input 13.
0 activates j, 7 and produces a tin output from terminal [IA.

The timer output setting 14 is determined by the time constant of the capacitor 54 externally connected to the terminals 7-T, and the variable resistance circuit 55/:, and the resistance value of the variable resistance circuit 55 is the peak value α.

It shall increase in proportion to 3 Yu. Therefore, the timer output setting time from the terminal QA of the first timer 50 is
value α. The length increases in proportion to the size of 8,1. The output QA of the first timer 50 is supplied to the input B of the second timer 510, and the second timer 51 has a fixed time constant determined by an externally connected capacitor 56 and a variable resistor 37. Then, the second timer 51 is activated by the rising edge of the first timer output, and the A N
Outputs a small signal with a time constant of 1 to the D gate 41a.

The operation of the variable timer 42a will be explained assuming that the wheel acceleration j*degree α1 is as shown in FIG. 5 and the output of the comparator 34a is as shown in FIG. From the moment when the output of the comparator 34a falls, the output QA of the first timer 5o becomes the peak value α1
The output low of the second timer 51 becomes Hl/bell for a predetermined time T2 from the falling instant of the output QA.

The pseudo vehicle speed generating device 27 has circuits 27a to 27c that individually generate pseudo vehicle speeds Vf 1 and 27c based on the wheel speed Vhll and VW3, and the circuits 27a to 27c that generate the pseudo vehicle speeds are also high values close to heavy speeds. and a select high switch 58 for selecting 2. Switch 58 is select I/high 1
Pseudo vehicle speed VrH is set as L1 wheel speed generation circuit 28a-28c.
＆This supply. j Snoring-like car series generation circuit 27a = 27c
The wheel speeds v, , 1. =, , =ν, , and also supplies an IR signal to the circuits 27a to 27e.
Since they have the same configuration, only the circuit 27a for creating the wheel speed ν and the pseudo vehicle speed Vfl will be briefly explained with reference to FIG. 6.

That is, the pseudo vehicle speed generating circuit 27a compares the wheel speed VWI with the comparator 59+60 supplied with one person's power, and calculates the pseudo vehicle speed with the comparator 59+60.
Set a dead zone of 1 km/h and use 7 comparators 59+6
It comprises an adder 61 and a subtracter 62 which are supplied with V0 to their other inputs, and a NOR gate 63 which is supplied with the outputs C, , C2 of the comparators 59, 60. Comparator 59 is VWI aL+ +
When the speed is 1 km/h (7), the output C is set to Hl/bel, and the comparator 60 sets the output C2 to H when the speed is ν1 - νt+-1km/11.
level. Thus, NOR Game Toro 3 has an output CI
IC2 is both 1. ■ 2 Shihekuru Shir + - 1 k
n+/h≦νwt<L++ lkm/! When +, II level is output 5'. The output of NOR Game Toro 3 is timer 6
4.01 Input to game H5 and shit health generation circuit 66. The timer 64 is started at the falling edge of the signal from the N01i' gate 63 (1), and runs for a fixed period of time T, (
For example, at 041 seconds, output I] level (K';
supply to.

The output of the OR gate C6 is supplied as a select signal S to the gate of an analog switch 67, and is also inverted by an inverter 68 and supplied to one input of an AND gate 69.70. The other input of AND gate 69 has C8
and the other input of AND gate 70 receives C! The outputs of AND gates 69.70 are supplied as select signals St and Ss to the gates of analog switches 71.72. The analog switch 67 is turned ON while the select signal S is at H level, and the supply voltage E to the integrating circuit 73 is set to 0.
The analog switch 72 is turned on during the H level of the select signal S4, and supplies the voltage E corresponding to the maximum possible vehicle acceleration (vehicle speed increase rate), for example +0.4 g, to the integrating circuit 73, and the analog switch 72 is turned on when the H level of the select signal S4 is set. The maximum value of possible vehicle deceleration (vehicle speed reduction change rate) when turned on, for example -1, 2
A voltage E corresponding to g is supplied to the integrating circuit 73.

The integrating circuit 73 is a well-known circuit consisting of an amplifier 74, a capacitor 75, and an analog switch 76. It is reset when the analog switch 76 is turned on by an H level reset signal S+ to its gate, and after the reset signal S1 disappears, the voltage E Let us continue to integrate. The reset signal SI is obtained by a shot pulse from the circuit 66, and this shot pulse generation circuit 66 first outputs one shot pulse as the reset signal S1 when the engine is started in response to the ignition turn-on signal IG, and then outputs an N shot pulse.
Every time the output of the OR gate 63 rises, a shot pulse is output as the reset signal S1.

The reset signal Sl is also supplied to a sample hold circuit 77.
This circuit is also used to reset the buffer amplifier 7B.
, 79, a well-known device consisting of a capacitor 80 and an analog switch 81, and inputs the wheel speed V□. The sample hold circuit 77 is reset when the analog switch 81 is turned on by the H level reset signal S1, continues to store the wheel speed v, 41 at that time as the wheel speed sampling value v1, and inputs this to the addition circuit 82. The adding circuit 82 adds the integral value v0=f (-E)・dt of the circuit 73 to the wheel speed sampling value v3, and then adds the integrated value v0=f (-E)・dt to the wheel speed sampling value v3, and then adds the integrated value v0=f (-E)・dt to the wheel speed sampling value v3, and then adds the integrated value v0=f (-E)・dt to the wheel speed sampling value v3, and then the added value Vs+V*
is input to the changeover switch 83.

The changeover switch 83 also has wheel speed v, 4. is also input, and this changeover switch sets the wheel speed V@I to the pseudo vehicle speed Vtt by the H level output of the AND gate 84 which takes the logical product of the H level MR signal and the H level CI signal, and otherwise sets the wheel speed V@I to the pseudo vehicle speed Vtt. The function is to set the value to the pseudo vehicle speed Vfl.

When the wheel speed VWI is as shown in FIG. 7, the pseudo vehicle speed generating circuit 27a can generate a pseudo vehicle speed Vfl as shown by the dotted line in FIG. 7 by the following operation. however,
In FIG. 7, the AND gate 84 in FIG. 6 does not output the H level, that is, the MR multiplied signal is at the L level (anti-skid control is not being executed as described later), or the signal C8 is at the low level (when the wheel speed VWt is not being executed). (during acceleration), the AND gate 84 is H.
The case where the selector switch 83 sets the output of the adding circuit 82 to the pseudo vehicle speed Vfl without outputting the level is shown.

Assuming that the engine is started at instant t0 in FIG. 7, the ignition switch signal fG causes the circuit 66 to output one shot pulse (reset signal) SI at this time.

This signal S resets the sample hold circuit 77 and holds the wheel speed vwI at this time as the wheel speed sampling value V as shown by the dashed line in FIG. On the other hand, the signal SI resets the integrating circuit 73, and its output V becomes 0, so the output V, +V, of the adding circuit 82 becomes V, which is taken as the pseudo vehicle speed Vfl. By the way, V is originally V
Since it is WI, Vfl”νw1, and the comparator output C
. This H level output is provided as a select signal S3 to turn on the analog switch 67, and on the other hand, it is inverted to L level by an inverter 68, and the select signal SZ, S
Prohibit the occurrence of 4.

Turning on the analog switch 67 keeps the input voltage E of the integrating circuit 73 at 0, and the integral value V remains at 0, so that the pseudo vehicle speed Vfl is kept at the same constant value as the wheel speed sampling value V.

When the wheel speed V□ increases due to wheel acceleration after instant t1, the signal C1 from the comparator 59 changes to the II level when VW≧Vr++1 km/h, and the output of the NOR gate 63 changes to the L level. However, since the timer 64 outputs an H level signal for 18 hours from that instant, 01
'l Gate 65 output S1 is T+11! β during which time elapses
; +11: 111. '・Hold the bell, instant t2
! :1. ．． The level is rolling. Therefore, instant t 1
``'-t, 2-minute mu''- even imitation car ifi V
f l is still the initial wheel speed simbling value v5
Same as - kept in a fixed planting.

Instant t, from now on! In this case, the output of OR game 1.65 is ■.

level, and the output C3 of the comparator 59 is )(l·Berue, 1·, so that the six i gates output (
1-11/Hel +,: +=,
When the analog switch 71 is turned on, the input voltage of the integrating circuit 73 is switched to a value corresponding to a vehicle acceleration of +0.4 g. Therefore, the integral value of A is ν.

=f (, -E)・at is 10. 4g acceleration6. ″′
Correspondence j, but6. The addition value of this and the wheel speed numbering value V, . . . by the circuit 82, that is, the pseudo vehicle speed Vfl, is also as shown in FIG. 7 (at a speed corresponding to the acceleration of +0.h, W - to do.

As a result, the pseudo vehicle speed Vfl becomes wheel speed VI, j - catching up <(Vw+<Vr++1.0km/h) instantaneous t
2. So a '3- C+ is 1, turned to level, NOR
The output of the OR gate 65 changes to H1/''. At this moment, the shot pulse generation circuit 66 generates the signal S11, which causes the integration circuit 73 and the IJ pull-hold circuit 77 to extend. However, since the wheel speed 1tu+ increases with the same tendency after that at instant t43B, a speed similar to 1↑(velocity Vfi) is created by the same action as above.

By the way, 1. At the instants t, 4...t, . , (The output of the IR game 1.65 is kept at 1. Hl, ·Bel by Kuimaro 4.

Follow 1. ``V, HI/-'' of secj/cut signal QS, which is the output of OR game 1.65, is the integral value ~ 1o
is kept at 0 and the instant t, 41. The wheel speed limp ring value V at
The fluctuation cycle of the one pseudo vehicle speed transparent wheel speed VWI can be kept constant for a short period of time.

Instant t0. After that, Vw+<Vr+-1km/h, and the situation is No+? Even after T3 time t7 has elapsed since the fall of the output of the gate h65, the output of the OR gate 65 increases at the elapsed instant t, 6 of 199 o'clock.
7, so (7 completed, νt=++<Vr+-1
km/h, the output of the comparator 60 is HL-bell, so the gate t-70 sets the select signal '554 Wabi II level to 1, and the analog switch 72 turns ON. -1.2 g of vehicle deceleration)
・Switch to the value corresponding to 1. Therefore, the integral value V, ・
, /''(-F)・dt, is a small speed corresponding to a deceleration of -1,2g (1:H:S, circuit of this and wheel speed limp ring value ν)] Added value by 2, In other words, pseudo vehicle speed V
ffl also corresponds to a deceleration of <-1, 2g as shown in FIG. 7, t1.
decreases at a faster rate.

As a result, the pseudo-111 speed νf1 changes to the wheel speed Vw+(7,
r to catch up (Vw+ to Vr+-1km/h)
At the instant t7, the signal C7 changes to bal-1/her, and the output of the NOR gate 63 changes to IIl novel. At this instant, the shot pulse generation circuit 6G issues a reset signal SI to reset the integration circuit 73 and sample halt circuit 77, but at the time tk 'Al♀, t, , Ni is the wheel speed V
Since the fluctuation period of w+ is shorter than 13 or does not fluctuate, the pseudo vehicle speed υ is constant, which is the same as the wheel speed - rimbling value V at the instant t7, in the same way as if the previous j point was 7 for the instant t a - t s. value is kept.

Also, after the instant t8, the wheel speed V□ decreases, so the above-mentioned 1. Same as 1.7, 1 pseudo vehicle speed V□A, 2T, in the middle of 1 hour, 1. It is possible to maintain the value up to 1, reduce the 4.2 g after the instantaneous LQ, correspond to the speed, and decrease it with the speed.

In addition, in the pseudo double continuous generation circuit shown in Fig. 6, MR (No. 3-) is between ■ ( level, that is, 11 A). , When the signal becomes ■1〕＜R, 脣11) Game 1
-84 sets the output to H level and switches the changeover switch 83, and during this time the pseudo vehicle speed v0 is set to the wheel speed V0, ignoring the above effect.
1. ．． Matches l. The reason for this is that during the period 1 and -, due to the above action, the pseudo vehicle speed νf1e+O,muQ, corresponds to 7
This is because if the wheel speed is made to go to the wheel speed V□, it will be too slow and the undesired control will become inaccurate.

Next, to explain the decompression speed control circuit 90X3 in FIG. The output of the changeover switch 92a is supplied 4''.
-,,l- Outputs the HL-bell signal from the town (-7, while the control signal S is 11 levels, the pulse generator (O5C) 9
3a outputs a constant periodic pulse signal (occurred during the H level of the AV, ' signal). Therefore, as will be explained later, the AND gate 91a controls the control signal AV, if the control signal S is at the L level while the brake fluid pressure is being reduced (during anti-skid control) when the AV,' signal is at the H level. 'By outputting the signal directly as an AV signal, rapid depressurization is executed, and if the control signal S is at H level, O5
By outputting the pulse signal from C93a as an AV signal, gradual pressure reduction is executed.

The control signal S, which thus determines the decompression speed, is transmitted to all anti-skid control channels 18a, 18b, 18c.
Decompression speed control circuits 90a, 90b, 90c in
The output of the flip-flop circuit 94 is common to both, and the level is determined according to the time indicated by 6 in FIG. 8 using the following configuration. That is, the flip-flop circuit 94 has a set input A.
The output of the ND gate 95 is connected, and when the output rises, the signal S5 is set to H level, and the MR multiplication signal is input to the reset input, and when the MR multiplication signal falls, that is, when the anti-skid control ends, the signal S5 is set to H level. Signal S
, shall be set to L level. One input of the AND gate 95 receives a shot pulse from a circuit 96 that generates one shot pulse every time the MR multiplied signal rises, and the output of the comparator 97 is supplied to the other input of the AND gate 95. do.

The comparator 97 is supplied with the output voltage resistance of the timer 98 on one hand, and the voltage corresponding to the set time Ts is supplied on the extraction input,
The measurement time resistance of the timer 98 is the set time T.

When the value is higher than that, the output is set to H level.

The timer 98 corresponds to the output of the deceleration detection circuit 99, and integrates the H level time of the output from when this output rises, and resets the integrated value when the output falls.

The deceleration detection circuit 99, as shown in FIG. 8, is constructed in the same manner as the pseudo vehicle speed generation circuit shown in FIG. 6. For this reason, the number 6 in Figure 8
Portions and signals corresponding to those in the figure are shown with the same reference numerals, but the input signal is select high pseudo vehicle speed V11. As is clear from the above, the output signal is C which becomes H level during deceleration.
This is input to the timer 98 as a 2 signal, and the set deceleration gradient selected by the analog switch 72 is set to a small value of about -0.4 g, which is slightly larger than the engine brake equivalent value.

The operation of the deceleration detection circuit 104 will be described when the select high pseudo vehicle speed VfN is as shown in FIG.
As is clear from the above explanation regarding FIGS. 6 and 7, the output of the changeover switch 83 is as shown in the dotted line in FIG. 9, and the sample-and-hold value v3 by the circuit 77 is as shown in the dashed line in the same figure. . Braking starts at instant tl in Fig. 9,
Wheel speed V of the right front wheel. 1 decreases as shown by the two-dot chain line, the reselect high pseudo vehicle speed VfM starts to decrease (decelerates) from the instant t2 when the set time T has elapsed from the braking start instant t, and the C2 signal becomes H level. The timer 98 measures a certain period of time, ie, deceleration time TM, as shown in FIG.

The comparator 97 in FIG. 1 has a deceleration time resistance of a set time T.

When the value is higher than that, an H level signal is output, and the AND gate 9
5 is when the shot pulse from the circuit 96 is input;
That is, if the above-mentioned state TM≧T occurs at the start of anti-skid when the MR multiplied signal rises, the flip-flop circuit 94 is set by the H level output and the signal S is set to the H level.

By the way, the set time T is determined in advance by considering the set time T from the braking start instant t1 to the drop start instant t2 of the select high pseudo vehicle speed VfH in FIG. Braking time with instant tl is 73+
When the voltage is equal to or higher than t, it becomes an H level.

As shown in FIG. 9, on a high friction road where the time ΔT from the start of braking to the start of anti-skid control is long, the output of the comparator 97 becomes H level before instant t, and instantaneously Upon receiving the shot pulse from the circuit 96 generated in response to the rise of the MR multiplied signal at t3, the AND gate 9
5 sets the output to H level at instant t3, and sets the output (control signal) SS of the flip-flop circuit 94 to H level.

The operation of the above embodiment will be representatively explained by taking the anti-skid control operation related to the right front wheel 1 as an example.

However, in the following, the wheel speed VWI of the right front wheel 1 and the select high pseudo vehicle speed Vf selected by the select high switch 58 are used.
H is as shown in Fig. 10 (VC is the actual vehicle speed shown for reference), and therefore the wheel acceleration α□ is as shown in the same figure, and the changeover switch 92a is set to I, 1/bel due to the low friction road. The explanation will be developed with reference to the control '4'R signal T S , -(F shown in the solid line position in FIG. 1).

1/4 Pedal 16 (see Figure 1)
, t at the time of interruption in FIG. More play 4 - Hydraulic pressure is generated! ,t
:, 1. ,,, the wheel speed ν is as shown in Fig. 10 < (,i
"-At the beginning of decreasing braking, the wheel deceleration Q: , , II is smaller than the base f value, and the output of the comparator 33a is
Since there is α, 〈a, and t), the comparator 34
The output of a is also [, 1, z < le, and the wheel speed ν is still ν without causing wheel slip.
Xo, 85 or more i-, or C2) The output of the comparator 35a is also 1-6L7. □, is le. Therefore, 01no・-1・
3G, U output is I, level, ANI) Gate 38a
The output (to ν1' signal) is also I''/<le, and AV! '
Signal ~・AV3'OR gate 29 that takes the logical sum of
In order to maintain the output of 1-2I/<, and to keep the MR multiplied signal from the pull timer 30 at -1,1 novel, A
The output of the ND gate 41a is also at level I5), and the output (EVI signal) of the OR gate 40a is also at level I. When the EVI signal is at level 17, the Eν valve 19a is opened and the AV
I' signal) 1, 1. The y bell makes the ΔC1 signal unfavorable 7 level and closes the 7AV block ↑20.1. Therefore, during this time, the Bo-Eel cylinder 1a△2's G L/-1-Liquid j P +-+
1-f from Tosta Schilling 11 (, this direction is above, 771., normal braking is obtained.

, during this braking, the ψ wheel deceleration rate ゛αI4,1 is based on P4 shift II) l), the instant tl...117, t
, I...-t%6. : 薯・9 and comparator 33H1 is 1
■ Output the level 7, width acceleration vagina α247. is based>1
``beyond a1, bffl*tt''-tA 1, t1
'Hereafter, U-, the ratio k 34 a is) l i・Berch l
output, wheel speed ν,5. ．． At the moment when 1, 2-・t, 6 becomes higher than the target vehicle transport speed, 1, t,′～・・t7. ', the comparator 35a outputs H) novel month. Follow me.
Fi V valve 19. signal becomes HI/bell between instants 1...t and 4. ) is closed (the ν1' signal goes to 6 during this period - time 1..1-1., and it becomes i'(+/ bell), and the AVI signal becomes IILy (bell'':!, ?':
Open the Av valve 20a. , '6Regami instantaneous t, l-・
・12 days 4. 2. 1) 1) The hydraulic pressure is maintained and the braking force is kept constant. 2.6.
i'x r<'; As well as determining the coefficient i'iJ,
After that, the anti-skid control that eliminates the J-removal is delayed with Jr.
? ,Rub.

1 and 2, wheel speed ν□ is target wheel speed νf□×0°)
At the instant t when 95 points are reached, the Rν valve 19a is held in the closed state, the Δν valve 20a is opened, and the Aν1' signal rises again. The pump 21a is driven by the energization of the IT/Y24.
Reduce the brake fluid pressure each time. By the way, in the above L7 case, the selector switch 92a is in the solid line position and the corresponding input of the A N D gate 91a is switched to the power supply. ) No. E (from 7 to HI-Bell, to l/1'
Signal j < 8 Vl as it is (becomes No. 3, continuous)
Perform the pressure reduction as described above, and then perform the rapid pressure reduction at -1. For this reason, on low-friction roads, sudden pressure reduction G11 is performed, and more Anna skid control is performed.2 (I/4 hydraulic pressure is too high and the braking distance is prevented from slipping due to slipping.) .In addition, the retriggerable timer 30 has AVI' = A
V3' signal) is triggered every 1, ;'=h, and emits a signal at level 11 for a predetermined time. From the second point, it is assumed that the l signal is maintained at the 1st point 7 after the instant t2.

The above hydraulic pressure changes the wheel acceleration α, 4.1 to η2 (1 ticket 1
(ll'+aμ,.

The AV valve 20X3 is closed at the instant t, which is reached, and the IEV valve 19a is maintained in the closed state and the phase 4g is maintained.
(T play 4□ ? ((Pressure 1) 11 is the holding number, -7 switching 2, Which C1, 2 is the road surface)? ■ It is possible to judge the change in the j coefficient, and the gray north of the 4. Re-raise it due to the decrease in hydraulic pressure (3, 1.) to avoid ζ- which delays the cancellation of anti-skid control in 2.

Such vibration -- i゛While the hydraulic pressure is maintained, the rotation of the road friction force jM
While the wheel speed Li1 reaches the value equivalent to the vehicle speed and increases, the wheel speed can be considered to have approached the value equivalent to the medium speed at the instant t4 when the wheel acceleration α□ becomes equal to or less than the reference value a. Therefore, as follows. I=, and raise the brake fluid pressure P8 by 1-2 again.

That is, at instants t and a, the outputs of the comparators 33a, 34a, and 35a are all 1. It's level L! 20. AVI from -
(AVI') Signal beam, L/bevel maintenance throat:
If the I iso1 signal goes to AND game 1, the signal from 41.3 determines "C1, Bell.AND game I□4
The tiJ strange tie 742a connected to the input of 1a is detected by the circuit 4411.
, the time T corresponding to the peak value α1.2 of l I ,
1. −j instantaneous (, HI for a certain period of time T3, delayed from 7.
・-・Pulse generator (OSC) 4
3a emits a constant frequency rectangular pulse shown in FIG. ANI) Game I 41a keeps the EVI signal at L level from instant t4 for T1 time from instant t4 and then for 12 hours from these reliable and MR double signal iI+/Hell middle bell logic bond 蓓-2.ru, 2k. The level is changed at the same period as the pulse signal from 0SC43a. Therefore, during time T1, the brake fluid pressure increases rapidly toward the master cylinder fluid pressure.
During time T2, the brake fluid pressure is gradually increased, and the brake fluid pressure becomes P. can be maintained for a long time near the lock hydraulic pressure PL corresponding to the ideal slip ratio at which maximum braking efficiency can be obtained, and the braking distance can be shortened.

After that, wheel deceleration α1. The instant t exceeds the reference value S
, l, the next skid cycle begins, and by repeating the same actions as described above, the brake fluid pressure of the front right wheel 1 is eventually controlled to maintain the ideal slip ratio, and the braking distance is kept as short as possible. Anti-skid control is executed.

The above is anti-skid control related to the front right wheel on a low-friction road, but on a high-friction road, as shown in Figure 9, when braking starts [
The time ΔT from , to the anti-skid start time t, is long (,
The comparator 97 has set its output to H level before the instant t. Therefore, at instant t3, the circuit 9
6 emits a chicot pulse, AND gate 95 goes high.
The level output sets the flip-flop circuit 94 and converts the signal S to H level. As a result, the changeover switch 92a is set to the dotted line position, and the AND game) 91a is
O5C93a during anti-skid when Vl' signal is H level
The pulse signal shown in FIG. 9 from 1 is used as an AVI signal. Therefore, during the anti-skid control on the high friction road, the brake fluid pressure Pw is intermittently reduced, and the pressure reduction speed is as shown by the dotted line in Fig. 9 on the low friction road in Fig. 10. On the other hand, high-friction roads result in lower speeds. Therefore, it is possible to prevent the brake fluid pressure from becoming too low on a high-friction road, resulting in a long braking distance, or from worsening steering stability due to a large imbalance in the braking forces between the wheels.

Note that the left wheel 2 and the rear two wheels 3.4 also have corresponding wheel speeds V, respectively. 2. Anti-skid control is similarly performed based on VH2 by the same effect as above.

FIG. 11 shows another example of the deceleration detection circuit 104. In this example, the base of the transistor 112 is connected between the normal brake switch 110 and the stop lamp 111, the collector of the transistor 112 is connected to the power supply +E and the input of the timer 98, and the emitter of the transistor 112 is grounded. Further, a NOT gate 113 is provided at the input of the timer 98.

In this example, when braking is started, the transistor 112 becomes conductive when the brake switch 110 is turned on to set the collector potential to 0, and the input of the timer 98 is set to H level by the NOT gate 113, and this state is maintained during braking.

Therefore, the signal from the NOT game 13 to the timer 93 is similar to the 02 signal in FIG.
Thus, the deceleration time TM can be measured.

(Effects of the Invention) Thus, the anti-skid control device of the present invention has the following effects as described above.
The road surface friction coefficient is determined and the speed of brake fluid pressure reduction during anti-skid control is controlled according to the determination result, which prevents brake fluid pressure from being reduced too much on high-friction roads, resulting in longer braking distance and unstable steering. In addition, it is possible to prevent the brake fluid pressure from decreasing on a low-friction road and the braking distance from increasing due to slipping.

Furthermore, since the road surface friction coefficient is judged based on the time from the start of braking to the start of anti-skid, it is possible to judge the road surface friction coefficient from the first skid cycle, and the above-mentioned decompression speed control is possible. and the effects thereof can be achieved from the first skid cycle.

[Brief explanation of the drawing]

Fig. 1 is an overall system diagram showing an embodiment of the anti-skid control device of the present invention, Fig. 2 is an electronic circuit diagram of a peak value detection circuit in the anti-skid control device, and Fig. 3 is an explanatory diagram of its operating waveforms. Fig. 4 is a circuit diagram of the variable timer in the anti-skid control device of Fig. 1, Fig. 5 is an explanatory diagram of the operating waveforms of the variable timer, and Fig. 6 is a circuit diagram of the variable timer in the anti-skid control device of Fig. 1.
Figure 7 is an electronic circuit diagram of the pseudo vehicle speed generation circuit in the anti-skid control device shown in Figure 7. Figure 8 is an electronic circuit diagram of the deceleration detection circuit in Figure 1. Circuit operation 'tlJ type 1. Yuku 1, 10th
FIG. 1 is an explanatory diagram of operating waveforms of the control device shown in FIG. 1, and FIG. 11 is a circuit diagram showing another example of the deceleration detection circuit. l...Right front wheel 2...Left front wheel 3.4...Rear wheel laS, 4a...Wheel cylinder 7...Pl] Pemi shaft 8...Differential sensor 4 Ni 9.10 ...Center shaft 11...2 system master - Schilling 1G...Brake pedals 17a, 17b, 11c, -'act, fu, king, -ri 18...Anti-skin 1 control circuit 19a, 19h, 19c =-EV valve 20a,
20b, 20c...AV valves 21a, 21h,
21c -, 1, 22a, 22b, 22c・
...Akyem 17-ta? ,,,3ii, 23h, 2
3c --fJ,, 7khalbu 24...pump drive 1,000-.zeta door? 5... Torque / register 26a, 26b, 26c --- Heavy 4 speed train - 1: Liner 27... Simulated vehicle speed generator 27a, 27b, 2-/c --- Pseudo double train generation circuit 28a, 28b, 28e...Target speed generation circuit 29...01 Magee 1.30...Retrigger filter 31a, 31b, 31c - = Middle wheel speed detection circuit 32
a, 32+), 32C...Wheel acceleration m' detection circuit 33a ==33c, 34a□, 34c, 35(1
−”35e −=Comparator 36a “36c, 40a−
・・40cm(',) For R game -37a =31c,
39a□=39c - amplifier 38a =38c -...
A N L) Game 141a = 41c −= A N
L) Gate 42a"・42c...1■Variable timer, 1
To 3a□ 43 c:...Pulse generator 44a...
44c...Peak value detection circuit 58...Select high speed switch 59, 60...Comparator 61...Adder 62...Subtractor 63...NOR game 1 64...Timer 65... ...Olmagate 66...Giggot pulse generation circuit 67, 71.72...Ano-gross isotiro B...
・Inverters 69, 70...AND game ・1・ 73...Integrator circuit 77...Zumblebold circuit 82...Addition circuit! :! 3...Switching switch 24.90a =90c...Decompression speed control circuit 91a, 9
5-=AND game 1・92.1...SJ replacement switch 93a...Pulse generator 94...Flip-flop circuit 96...Shot pulse input generation circuit 97...Comparator 9th ...Timer 99...Deceleration detection circuit 110...Break -4゛ switch 111...Single lamp 112...Transiter 113...Nr) i" game -1 Patent applicant
1-1 San Autotun Co., Ltd. Figure 9-QQI"1, --

Claims (1)

[Scope of Claims] 1. In a device that performs anti-skid control that prevents wheel lock by reducing brake fluid pressure when a wheel locks during braking that generated brake fluid pressure, An anti-skid control device characterized by being provided with a timer for measuring the time until the skid starts, and a pressure reduction speed control means for slowing down the pressure reduction when the time is long, and rapidly reducing the pressure when the time is short. .