JPH0885437A - Antiskid device for automobile - Google Patents

Abstract

PURPOSE: To apply a smooth and stable brake at the time of a quick turn. CONSTITUTION: The brake pressures of wheels are controlled by the first and second negative pressure control valves 8, 9 and an atmospheric pressure control valve 11 at the same time. An ECU 26 calculates the estimated vehicle body speed and lateral acceleration (lateral G) based on the wheel speed information by wheel speed sensors 22-25. When the lateral G does not exceed the prescribed quick turn judgment level, the ECU 26 conducts the antiskid control to reduce or hold the braking pressure at the normal reduction start timing based on the wheel speed information of each wheel. When the lateral G exceeds the prescribed quick turn judgment level, the ECU 26 conducts the antiskid control to reduce or hold the braking pressure earlier than the normal reduction start timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile antiskid device.

[0002]

2. Description of the Related Art In this type of anti-skid device, a wheel speed sensor for detecting the wheel speed is provided for each wheel.
Based on the wheel speed information from the sensor, the wheel having the lowest wheel speed is used as a control reference wheel to increase or decrease the braking pressure. Also,
In response to the sudden turning on a high μ road where the load balance of the four wheels is broken, which is a problem of this type of device, in recent years, a device has been proposed in which the control characteristic is changed according to the turning state of the vehicle body. .

For example, in the anti-skid device disclosed in JP-A-1-204850, the lateral acceleration of the vehicle body is detected,
When the lateral acceleration is equal to or greater than the set value and the vehicle speed is equal to or greater than the set value, it is considered that the vehicle body is making a sharp turn (J turn), and the control characteristic is switched from the normal characteristic to the turning characteristic. .

[0004]

However, in the above-mentioned conventional anti-skid device, although the control concept of changing the control characteristic at the time of a sharp turn is shown, in order to realize smooth and highly stable braking, However, a more realistic anti-skid device has been desired.

The present invention has been made in view of the above problems, and an object thereof is to provide an anti-skid device for an automobile capable of realizing smooth and highly stable braking during a sharp turn. To provide.

[0006]

In order to achieve the above object, the invention according to claim 1 applies braking to a plurality of brake wheel cylinders provided for each wheel M2, as shown in FIG. A braking control actuator M3 for simultaneously controlling the pressure, a wheel speed detecting means M4 for detecting the wheel speed of each wheel M2, and a turning state detecting means for detecting that the turning state of the vehicle body M1 has reached a predetermined sharp turning level. M5,
When a sudden turn is not detected by the turning state detecting means M5,
The braking control actuator M is configured to reduce or maintain the braking pressure at a predetermined control start timing based on the wheel speed information for each wheel M2 by the wheel speed detection means M4.
When a sudden turn is detected by the first braking control means M6 for driving the vehicle 3 and the turning state detection means M5, the first braking control means M6 starts the control start timing according to the detected sudden turning state. Is also provided with a second braking control means M7 for driving the braking control actuator M3 so as to reduce or maintain the braking pressure at an early stage.

According to a second aspect of the invention, in the first aspect of the invention, the turning state detecting means M5 is means for detecting a lateral acceleration of the vehicle body M1, and the second braking control means M7. Is configured to accelerate the control start timing when the lateral acceleration exceeds a predetermined level.

According to a third aspect of the invention, in the first aspect of the invention, the turning state detecting means M5 is means for detecting a combined acceleration of the lateral acceleration and the longitudinal acceleration of the vehicle body M1. The second braking control means M7 is
In the period from the start of the brake operation to the start of the control by the first braking control means M6, the braking pressure is reduced or held only when the combined acceleration exceeds a predetermined level.

According to the invention described in claim 4, as shown in FIG. 11, a braking control actuator M13 for simultaneously controlling the braking pressure for a plurality of brake wheel cylinders provided for each wheel M12, and each wheel M12. Wheel speed detecting means M14 for detecting the wheel speed of each wheel, and braking control means M15 for controlling the braking pressure based on the wheel having the most locking tendency from the wheel speed information by the wheel speed detecting means M14.
And a rear inner wheel lift detection means M16 for detecting the occurrence of locking of the rear inner wheel when the vehicle body M11 turns, and the braking control means M15 uses the rear inner wheel lift detection means M16. It is a gist to control the braking pressure based on the wheel speed information of the wheels other than the rear inner wheel when the lock occurs due to the lifting of the vehicle.

According to the invention described in claim 5, claims 1 to 4 are provided.
In the invention described in any one of the above 1, when the lateral acceleration of the vehicle bodies M1 and M11 exceeds a predetermined determination level, the vehicle body speed serving as a reference for control is switched independently from left and right independently of all the wheels so far. are doing.

[0011]

According to the first aspect of the invention, when the turning state detecting means M5 does not detect a sudden turn, the first braking control means M6 causes the wheel speed detecting means M4 to detect each wheel M.
The braking control actuator M3 is driven so as to reduce or maintain the braking pressure at a predetermined control start timing based on the wheel speed information for each two. Further, the turning state detecting means M
At the time of detecting a sudden turn by the vehicle No. 5, the second braking control means M7 reduces or holds the braking pressure earlier than the control start timing by the first braking control means M6 according to the detected sudden turning state. The braking control actuator M3 is driven so that The braking control actuator M3
The braking pressure of each wheel M2 is simultaneously controlled by driving.

In short, when the vehicle body M1 makes a sharp turn, the wheels located at the rear inner wheels tend to lift up and tend to lock quickly. In this case, the wheel speed of the same wheel suddenly decreases, and it is easy to cause unstable factors such as a drop in braking pressure and oversteer. However, according to the present configuration, the instability factor is eliminated and the smooth and stable turning operation is realized by accelerating the control start timing of the braking pressure during the braking in the sudden turning state.

According to the second aspect of the present invention, the turning state detecting means M5 detects the lateral acceleration of the vehicle body M1, and the second braking control means M7 detects when the lateral acceleration exceeds a predetermined level. Advance the control start timing. In this case, the unstable behavior of the vehicle body that occurs during braking in a sharp turning state is suppressed in advance.

According to the third aspect of the invention, the turning state detecting means M5 detects the combined acceleration of the lateral acceleration and the longitudinal acceleration of the vehicle body M1, and the second braking control means M7.
Reduces or holds the braking pressure only when the combined acceleration exceeds a predetermined level in the period from the start of the brake operation to the start of the control by the first braking control means M6. In this case, the unstable behavior of the vehicle body that occurs during braking in a sharp turning state is suppressed in advance.

According to the fourth aspect of the invention, the braking control means M15 controls the braking pressure with reference to the wheel having the most locking tendency from the wheel speed information from the wheel speed detecting means M14. Further, when the rear inner wheel lift detection means M16 detects the occurrence of a lock due to the lift of the rear inner wheel when the vehicle body M11 is turning, the braking control means M15 performs braking based on the wheel speed information of the wheels other than the rear inner wheel. Control the pressure.

That is, as described above, during a sharp turn, the rear inner wheel floats up and is easily locked. Therefore, in the case of so-called low select control in which the braking pressure is controlled with the wheel having the most locking tendency as a reference, a sufficient braking pressure cannot be obtained thereafter by using the lock wheel as a reference. However, according to this configuration, a desired braking pressure can be obtained even after the rear inner wheel is locked.

According to the invention of claim 5, the vehicle body M
When the lateral accelerations of M1 and M11 exceed a predetermined determination level, the vehicle speed that serves as a reference for control is switched from the same value for all the wheels until then to the left and right independently. In this case, control suitable for the turning state of the vehicle body is realized.

[0018]

【Example】

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a hydraulic circuit diagram showing an outline of an automobile antiskid device constituted by two hydraulic systems of an X pipe (diagonal pipe). In the anti-skid device of FIG. 1, a brake booster 2 that boosts the depression force of the pedal 1 is connected to the brake pedal 1, and a tandem master cylinder 12 is connected to the brake booster 2. The brake booster 2 utilizes the pressure difference between the negative pressure of the intake manifold (intake negative pressure) generated in the engine 28 and the atmospheric pressure, and uses the brake pedal 1
The master cylinder 12 adjusts the pressure difference with the depression of
The force applied to the piston (not shown) is increased.

Specifically, the brake booster 2 has a first power cylinder 4 and a second power cylinder 4 which are partitioned by a diaphragm 3.
The power cylinder 5 is formed. The intake negative pressure of the engine 28 is introduced into the first and second power cylinders 4 and 5 through the negative pressure ports 6 and 7, and the negative pressure level thereof is the electromagnetic 2-position control valve. The negative pressure control valve 1 and the second negative pressure control valve 9 are controlled according to the communication / cutoff operation. First and second negative pressure control valves 8, 9
Is controlled in position by the ECU 26,
When there is no input signal from (no coil excitation), the first negative pressure control valve 8 is held in the communicating position and the second negative pressure control valve 9 is held in the shut-off position (state shown in the figure).

Atmospheric pressure is introduced into the second power cylinder 5 through the atmospheric pressure port 10. At this time, the atmospheric pressure is adjusted by a pressure adjusting valve (not shown) according to the depression of the brake pedal 1 and is introduced into the second power cylinder 5. Therefore, the second power cylinder 5 causes a large pressure difference with respect to the first power cylinder 4. The opening / closing of the atmospheric pressure port 10 is controlled by an atmospheric pressure control valve 11 which is an electromagnetic two-position control valve. The atmospheric pressure control valve 11 is
When there is no input signal from the ECU 26 (when the coil is not excited), it is held at the communication position (state shown in the figure).

The master cylinder 12 is the first hydraulic port 1
3 and a second hydraulic pressure port 14, of which the first hydraulic pressure port 13 is connected to the right front (F
The wheel cylinder 17 for the (R) wheel and the wheel cylinder 18 for the left rear (RL) wheel are in communication. In addition, the second hydraulic port 14 is connected to the right rear (R
The wheel cylinder 19 for the (R) wheel and the wheel cylinder 20 for the left front (FL) wheel are in communication. Hydraulic piping 15,
A P valve (proportioning valve) 21 for generating a hydraulic pressure difference between the front wheels and the rear wheels is provided on the left and right rear (RL, RR) wheels of the vehicle 16.

Each wheel is provided with a wheel speed sensor 22, 23, 24, 25 for detecting the wheel speed of each wheel, and each sensor signal has an electronic control device (hereinafter referred to as EC
U) 26. These wheel speed sensors 2
As 2 to 25, for example, an electromagnetic pickup type sensor or a photoelectric conversion type sensor is used. Further, the brake pedal 1 is provided with a brake switch 27 for detecting the presence / absence of a pedal depression operation, and the detection signal is a ECU 2
6 is input.

The ECU 26 is mainly composed of a microcomputer, and calculates the estimated vehicle body speed based on the input signals from the wheel speed sensors 22 to 25. And E
The CU 26 determines the lock tendency of each wheel from the estimated vehicle body speed and the wheel speed, and also determines the anti-skid control mode of each wheel. At this time, the ECU 26 executes the anti-skid control based on the control mode of the wheel that shows the most locking tendency (low select control).

In this embodiment, the brake booster 2, the first and second negative pressure control valves 8 and 9, and the atmospheric pressure control valve 11 are used.
The master cylinder 12 constitutes a braking control actuator, and the wheel speed sensors 22 to 25 constitute wheel speed detecting means. Further, the ECU 26 constitutes a turning state detecting means, a first braking control means, a second braking control means, a braking control means, and a rear inner wheel floating detection means.

The operation of the antiskid device in each antiskid control mode (pressure increasing mode / holding mode / pressure reducing mode) will be briefly described. First, in the pressure increase mode (state of FIG. 1), the ECU 26 determines that the first negative pressure control valve 8 is in the communicating position, the second negative pressure control valve 9 is in the shut-off position, and the atmospheric pressure control valve 11 is in the communicating position. Located in. Then the first
The intake negative pressure from the engine 28 acts on the power cylinder 4, and the atmospheric pressure acts on the atmospheric pressure port 10 of the second power cylinder 5. At this time, the brake booster 2 operates in accordance with the pressure difference between the intake negative pressure and the pressure of the second power cylinder 5 regulated by the pressure regulating valve (not shown) in response to the depression operation of the brake pedal 1. The force applied to the cylinder 12 is boosted. as a result,
The hydraulic pressure generated by the master cylinder 12 rises, and the wheel cylinders 17 to 20 are pressurized.

In the holding mode, the ECU 26 positions the first negative pressure control valve 8 in the shutoff position, the second negative pressure control valve 9 in the shutoff position, and the atmospheric pressure control valve 11 in the shutoff position. Then, the intake negative pressure and the atmospheric pressure to the first and second power cylinders 4 and 5 are shut off, and the pressure difference between the first power cylinder 4 and the second power cylinder 5 is maintained,
The braking pressure of the wheel cylinders 17 to 20 is held together with the hydraulic pressure generated in the master cylinder 12.

Further, in the depressurization mode, the ECU 26
The first negative pressure control valve 8 is in the shut-off position, and the second negative pressure control valve 9 is
To the communicating position and the atmospheric pressure control valve 11 to the shut-off position. Then, the first and second power cylinders 4 and 5 are communicated with each other, and the pressure difference decreases, so that the hydraulic pressure of the master cylinder 12 decreases. As a result, the wheel cylinders 17 to 20 are depressurized.

Next, the unique operation and effect of this embodiment will be described with reference to FIGS. Here, FIG. 2 shows EC
It is a flowchart which shows the anti-skid control routine performed by U26, and FIGS. 3, 5, and 7 are the subroutines of FIG.

Now, when the routine of FIG. 2 starts,
The ECU 26 firstly determines in step 100 the wheel speed sensor 2
Wheel speed V obtained from the detection results of 2 to 25_WEnter
It Then, the ECU 26 determines in step 101 the wheel speed.
V_WBased on the wheel acceleration G_WIs calculated and
Estimated vehicle speed V at step 102_SOAnd estimated vehicle body acceleration G _SO
And calculate. Further, the ECU 26 determines in step 103
Calculate the estimated lateral acceleration of the vehicle body (hereinafter referred to as lateral G)
And estimated vehicle body acceleration G_SOAnd estimated lateral acceleration of lateral G
The degree (hereinafter referred to as “composite G”) is calculated.

Here, lateral G = {V _SO · (V _O −V _i )} / B composite G = √ (G _SO ² + horizontal G ² ), where V _O : outer wheel maximum wheel speed V _i : inner wheel maximum Wheel speed B: The tread of the vehicle body.

Further, in step 104, the ECU 26 calculates the longitudinal load movement amount ΔW _X and the lateral load movement amount ΔW _Y. Here, ΔW _X = W · G _X · (H / 2L) ΔW _Y = W · G _Y · (H / 2B) where W: vehicle weight G _X : braking deceleration (= estimated vehicle acceleration G _SO ) G _Y : lateral GH: height of the center of gravity of the vehicle body L: wheelbase of the vehicle body It should be noted that the estimation calculation of the vehicle body behavior based on these wheel speeds is advantageous in calculation accuracy because there are two or more wheels that do not reach the braking limit in the braking control actuator that simultaneously controls a plurality of wheels of this type.

Then, the ECU 26 determines in step 105 whether the lateral G exceeds the first determination value G ₁ . When lateral G ≦ G ₁ , the ECU 26 proceeds to step 107 and sets the same reference speed V _SO for the four wheels (equal to the estimated vehicle body speed V _SO at step 102). If lateral G> G ₁ , the ECU 26 proceeds to step 106 to set left and right independent reference speeds V _S1 and V _S2 .

Next, the ECU 26 determines in step 108 whether or not the brake switch 27 is on. If the switch = off, the process returns to step 100, and if the switch = on, the control mode in step 200 to be described later is performed. Execute the setting routine. After that, the ECU 26 outputs a control signal to each of the control valves 8, 9 and 11 in step 109 based on the control mode set in step 200.

Now, the control mode setting routine of step 200 will be described. This control mode setting routine is for realizing anti-skid control according to the turning state when the vehicle body is turning, and specifically, for example, one of those shown in FIGS. 3, 5, and 7. A control program is implemented. 4, 6, and 8 are timing charts showing the processing operation of each control mode setting routine more specifically. The detailed contents of the routine will be described below in the order of FIG. 3, FIG. 5, and FIG.

In the control mode setting routine shown in FIG. 3, the ECU 26 determines in step 201 that the lateral G is the second.
Is larger than the judgment value G ₂ (> G ₁ ) of. If lateral G ≦ G ₂ , the ECU 26 proceeds to step 203.
The threshold value of the slip ratio, which serves as a criterion for starting the pressure reduction, is set so that the pressure reduction is started at a normal timing assuming straight running (normal pressure reduction start timing process). On the other hand, if the lateral G> G ₂ , the ECU 26 determines in step 202
Then, the threshold value of the slip ratio is set to be smaller than the normal time so that the pressure reduction is started earlier than the normal timing (timing of step 203) (the pressure reduction start timing early process).

After that, the ECU 26 determines the control mode for each wheel in step 204. That is, the ECU 2
6 uses a mode determination map represented by a threshold value of the slip ratio and a threshold value of the wheel acceleration G _W (deceleration), and uses one of the pressure increasing / holding / depressurizing control modes for each wheel. To judge. Then, the ECU 26 continues in step 2
In 05, the control mode at that time is determined based on the control mode of the wheel showing the most locking tendency among all the four wheels (four-wheel low select), and then this routine is terminated and the routine returns to the routine of FIG.

The operation of the routine of FIG. 3 will be described more specifically with reference to the timing chart of FIG. In FIG. 4, the lateral G is generated by the turning of the vehicle body, and the lateral G is the time t.
The first judgment value G ₁ is exceeded at ₁ , and the second judgment value G ₂ is exceeded at time t2. When the brake pedal 1 is depressed at time t3, braking force is generated. And
When the pressure reduction is started at time t4, the braking force temporarily decreases, and thereafter, the braking force increases as the wheel speed recovers. After time t2, step 201 in FIG. 3 becomes YES, so this time t4 is the decompression start timing that is earlier than usual.

That is, when the brake is applied when the vehicle body makes a sharp turn, the rear inner wheel tends to float up, and then the wheel speed of the inner wheel decreases the fastest. In this case, as shown by the broken line in the figure, in the conventional control in which the pressure reduction start timing is not changed to the early side, the locking tendency of the rear inner wheels (reduction of the rear inner wheel speed) becomes significant before the pressure reduction comes into effect. Subsequent recovery of braking force will be significantly delayed. Further, as shown at time t5, oversteer is likely to occur due to the delay in the start of pressure reduction. On the other hand, according to the process of FIG.
In 02, the decompression start timing is advanced and the reduction in speed of the rear inner wheel is suppressed to a small level. As a result, the locking tendency of the rear inner wheel is quickly eliminated, the recovery of the braking force is accelerated, and smooth and highly stable braking can be achieved during a sharp turn.

Next, in the control mode setting routine shown in FIG. 5, the ECU 26 sets the threshold value of the slip ratio so that the normal pressure reduction start timing is obtained in step 211. After that, the ECU 26 determines in step 212 whether or not it is before the start of the anti-skid control (before the start of decompression), and in the following step 213, the combined G is the third determination value G.
₃ Determine whether it exceeds (> G ₁ , G ₂ ).

In this case, if step 212 is YES and step 213 is NO (before the start of anti-skid control, if the combined G ≦ G ₃ ), the ECU 26 proceeds to step 21.
5, the control mode is set to the pressure increasing mode, and then the process returns to the routine of FIG. If both steps 212 and 213 are YES (before the start of the anti-skid control and the combined G> G ₃ ), the ECU 26 proceeds to step 214 to set the control mode to the holding mode (or the gradual reduction mode), and Two
Return to the routine.

If step 212 is NO (after anti-skid control), the ECU 26 proceeds to step 2
Proceed to 16. Then, the ECU 26 determines the control mode for each wheel according to the wheel speed in step 216, and determines the control mode at that time based on the wheel having the most locking tendency in the following step 217. This step 21
The processing of Nos. 6 and 217 is the normal four-wheel row select processing.

The operation of the routine of FIG. 5 will be described more specifically with reference to the timing chart of FIG. Note that in FIG. 6, time t23 indicates the start timing of the anti-skid control.

Now, in FIG. 6, when the combined G increases due to the turning of the vehicle body and the brake pedal 1 is depressed at time t21, the lateral G decreases thereafter substantially uniformly, whereas the combined G decreases due to braking. It changes while pulsating due to the disturbance of wheel rotation. Then, in the period from time t21 to time t23,
Braking control is performed in the pressure increasing mode or the holding mode depending on whether or not the combined G> G ₃ . That is, for example, at the time t21 when the combination G ≦ G ₃ , the step 2 in FIG.
By the processing of 15, the hydraulic pressure is increased and the braking force is increased.
In addition, for example, synthetic G> G ₃ become time t22, 5
The braking force is held by the processing of step 214 of. Then, after time t23, steps 216 and 217 of FIG.
The four-wheel low select is carried out by the processing of.

That is, when the brake is applied when the vehicle body makes a sharp turn, a sudden decrease in the rear inner wheel speed and a synthetic G pulsation occur. In this case, as shown by the broken line in the figure, in the conventional control in which the pressure increasing mode is always set before the start of the anti-skid control, it takes time to recover the braking force due to the remarkable tendency of the rear inner wheel to lock. On the other hand, according to the processing of FIG. 5, the unstable element of the vehicle body including the locking tendency of the rear inner wheel is determined by the increase of the composite G, and the braking force is held (or relaxed) in order to eliminate the unstable element. Be reduced). as a result,
The braking force is quickly recovered, and smooth and highly stable braking can be realized during a sharp turn.

Next, in the control mode setting routine shown in FIG. 7, the ECU 26 sets the threshold value of the slip ratio so that the normal pressure reduction start timing is obtained in step 221. Further, the ECU 26 determines the control mode for each wheel in step 222. After that, the ECU 26 determines whether or not the rear inner wheel is lifted up in steps 223 and 224. Specifically, the ECU 26 determines in step 223 whether or not the rear inner wheel is locked, and then in step 22
At 4, it is determined whether the total load movement amount of the vehicle body exceeds the rear inner wheel load. Here, the total load movement amount is obtained from the sum of the longitudinal load movement amount ΔW _X and the lateral load movement amount ΔW _Y (= ΔW _X + ΔW _Y ), and the rear inner wheel load is obtained in advance for each vehicle body. .

In this case, if either of the steps 223 and 224 is NO, the ECU 26 proceeds to step 226 on the assumption that the rear inner wheel is not lifted up, and uses the determination result of the control mode of the step 222 to determine the four wheels. The control mode at that time is determined based on the wheel having the most locking tendency among them (four-wheel low select). If both steps 223 and 224 are YES, the ECU 26
Step 225, assuming that the rear inner ring has lifted up.
Then, the control mode at that time is determined based on the wheel having the most locking tendency among the three wheels excluding the rear inner wheel, using the determination result of the control mode in step 222 (three-wheel low select).

The operation of the routine of FIG. 7 will be described more specifically with reference to the timing chart of FIG. In FIG. 8, the time t31 indicates the start of braking and the time t3 indicates
2 indicates that the rear inner wheel is locked, and time t33 indicates that the rear inner wheel is unlocked.

In FIG. 8, when the vehicle body turning increases the vehicle body load movement amount and the brake pedal 1 is depressed at time t31, the lateral load movement amount ΔW _Y decreases substantially uniformly. , Total load movement (= ΔW _X + Δ
W _Y ) changes while pulsating. And time t31 ~
During the period of t32, the four-wheel low select process is executed by the process of step 226 of FIG. Further, during the period from time t32 to t33 when the rear inner wheel is locked and the total load movement amount exceeds the rear inner wheel load W _R , the three wheels other than the rear inner wheel (lock wheel) are locked by the processing of step 225 in FIG. Select processing is performed. After that, when the rear inner wheel is unlocked at time t33, the three-wheel low-select processing is switched to the four-wheel low-select processing.

That is, when the brake is applied when the vehicle body makes a sharp turn, the rear inner wheel is lifted by the load movement of the vehicle body, and the rear inner wheel is easily locked. In this case, as shown by the broken line in the figure, the braking force is significantly reduced by the conventional control in which the four-wheel low-select control is performed even when the rear inner wheel is lifted and locked, and the braking force is hardly obtained at that time. Also, it takes a lot of time to recover the braking force thereafter. On the other hand, according to the process of FIG. 7, the low select control is performed for the three wheels other than the rear inner wheel, so that the reduction of the braking force is suppressed to the minimum. In this case, a desired braking force can be obtained although the timing of unlocking the rear inner wheel is slightly delayed. As a result, even in the processing of FIG. 7, it is possible to realize smooth and highly stable braking during a sharp turn.

As described in detail above, the antiskid device of this embodiment has three control methods, but in any case, the object of the present invention can be achieved. (Second Embodiment) The antiskid control described in the first embodiment can achieve the object of the present invention even if it is embodied in an antiskid device having another structure. The second embodiment in which the configuration of the device is changed will be described focusing on the differences from the first embodiment. That is, in the first embodiment, the first and second brake boosters 2 are
Although the hydraulic pressure of the master cylinder 12 is controlled by controlling the pressure acting on the second power cylinders 4 and 5, in the second embodiment, the hydraulic pressure control circuit is configured on the downstream side of the master cylinder 12. ing.

FIG. 9 shows the structure of the anti-skid device in the second embodiment. In FIG. 9, the second hydraulic pipe 16 has a pressure increasing control valve 3 including an electromagnetic two-position switching valve.
0, pressure reducing control valve 31, reservoir 32, and drive motor 3
4 is provided with a hydraulic pump 33, which constitutes a hydraulic control circuit. Then, a braking control actuator (control valves 30, 3 of this hydraulic control circuit
1, the command from the ECU 26 given to the drive motor 34), the right rear (RR) wheel connected to the second hydraulic pipe 16,
The braking pressure of the wheel cylinders 19 and 20 for the left front (FL) wheel is controlled.

On the other hand, the first hydraulic pipe 15 has a right front (F
R) wheel, left rear (RL) wheel wheel cylinders 17, 18
A modulator 35 is provided for indirectly controlling the braking pressure in response to the hydraulic pressure in the second hydraulic pipe 16. The modulator 35 adjusts the hydraulic pressure on the wheel cylinder side of the first hydraulic pipe 15 to be substantially equal to the hydraulic pressure on the wheel cylinder side of the second hydraulic pipe 16.

The operation of the modulator 35 will be briefly described for each control mode. In the normal braking state, the second hydraulic pipe 16 is operated.
Is introduced into the second pressure chamber 40 of the modulator 35, and the piston 38 moves to the left in the figure. At this time, the valve body 36 and the valve seat 37 separate from each other, and the master cylinder 12
Receives the hydraulic pressure from the wheel cylinders 17 and 18
Is increased. In the holding mode, the piston 38 is stationary at a certain position with the piston 38 moving to the right and the valve body 36 and the valve seat 37 contacting each other, so that the braking pressure of the wheel cylinders 17 and 18 is held. It In the depressurization mode, the piston 38 moves further to the right with the valve element 36 and the valve seat 37 in contact with each other, and the wheel cylinders 17 and 18 depressurize as the pressure decreases due to the volume expansion of the first pressure chamber 39. To be done. Further, in the pressure increasing mode, the valve body 36 and the valve seat 3 are
The piston 38 moves to the left in the state where the wheel cylinders 17 and 18 are in contact with each other, and the wheel cylinders 17 and 18 are pressurized as the pressure increases due to the volume reduction of the first pressure chamber 39.

In the antiskid device having the above construction, the same antiskid control as in the first embodiment is carried out (the processing shown in FIGS. 2, 3, 3 and 5, etc.). In this case, the ECU 26 controls the pressure increase control valve 30, the pressure reduction control valve 31,
A control command is issued to the drive motor 34.

The present invention can be embodied in the following modes other than the above embodiment. (1) In the above embodiment, the control mode is determined for each wheel, and then the control mode actually used is determined based on the wheel having the most locking tendency. However, this method can be changed. Good. For example, a wheel serving as a control reference (control reference wheel) may be directly selected from the wheel speeds of the four wheels, and the actual control mode may be determined from the wheel speed of the control reference wheel.

(2) In the routine shown in FIG. 3, the degree of accelerating the pressure reduction start timing in step 202 may be determined in proportion to the magnitude (value) of the lateral G. (3) In the routine of FIG. 7, the lift of the rear inner wheel was detected by the amount of load movement (step 224). However, the time from the start of braking to the lock of the rear inner wheel was measured, and the lift was detected when the time was extremely short. You may change to another method, such as determination.

(4) In each of the above-described embodiments, the one-channel type anti-skid device is embodied, but the two-channel type in which the left and right wheels of the vehicle body are independently controlled, and the front wheel independent-
It may be embodied in a device having another control system such as a rear-channel simultaneous three-channel system.

(5) In the above embodiment, the wheel speed is used to detect the turning state. However, an acceleration sensor (G sensor) is provided to directly detect the acceleration acting in the lateral or longitudinal direction of the vehicle body. You may do it.

[0060]

According to the invention described in claim 1, the excellent effect that smooth and highly stable braking can be realized at the time of a sharp turn is exhibited.

According to the invention described in claims 2 and 3, the unstable behavior of the vehicle body that occurs during braking in a sharp turning state can be suppressed in advance. According to the invention described in claim 4, it is possible to obtain a desired braking pressure even after the rear inner wheel is locked during a sharp turn.

According to the fifth aspect of the present invention, it is possible to realize the control suitable for the turning state of the vehicle body.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing a configuration of an automobile anti-skid device according to a first embodiment.

FIG. 2 is a flowchart showing an anti-skid control routine executed by an ECU.

3 is a control mode setting routine of FIG. 2 (step 20);
It is a flowchart which shows 0).

FIG. 4 is a timing chart for explaining the routine of FIG. 3 more specifically.

5 is a control mode setting routine of FIG. 2 (step 20).
It is a flowchart which shows 0).

FIG. 6 is a timing chart for explaining the routine of FIG. 5 more specifically.

FIG. 7 is a control mode setting routine (step 20 in FIG. 2).
It is a flowchart which shows 0).

FIG. 8 is a timing chart for explaining the routine of FIG. 7 more specifically.

FIG. 9 is a hydraulic circuit diagram showing a configuration of an automobile anti-skid device according to a second embodiment.

FIG. 10 is a block diagram corresponding to a claim.

FIG. 11 is a block diagram corresponding to a claim.

[Explanation of symbols]

2 ... Brake booster as braking control actuator, 8 ... First negative pressure control valve as braking control actuator, 9 ... Second negative pressure control valve as braking control actuator, 11 ... Atmospheric pressure control as braking control actuator Valves, 12 ... Master cylinders as braking control actuators, 17-20 ... Wheel cylinders, 22-25
... a wheel speed sensor as wheel speed detecting means, 26 ... turning state detecting means, first braking control means, second braking control means, braking control means, E as rear inner wheel lock detecting means
CU, 30 ... pressure increasing control valve as braking control actuator, 31 ... pressure reducing control valve as braking control actuator, 34 ... drive motor as braking control actuator, 35 ... modulator as braking control actuator.

Claims (5)

[Claims] 1. A braking control actuator for simultaneously controlling a braking pressure for a plurality of brake wheel cylinders provided for each wheel, a wheel speed detecting means for detecting a wheel speed for each wheel, and a turning state of a vehicle body. A turning state detecting means for detecting that a predetermined turning level has been reached, and when the turning state detecting means does not detect a sharp turning, a predetermined speed is determined based on wheel speed information for each wheel by the wheel speed detecting means. First braking control means for driving the braking control actuator so as to reduce or maintain the braking pressure at the control start timing; and when the turning state detecting means detects a sudden turning, depending on the detected sudden turning state. , Driving the braking control actuator so as to reduce or maintain the braking pressure earlier than the control start timing by the first braking control means. Automotive anti-skid device, characterized in that a second braking control means. 2. The turning state detecting means is means for detecting a lateral acceleration of the vehicle body, and the second braking control means sets the control start timing when the lateral acceleration exceeds a predetermined level. The automobile anti-skid device according to claim 1, which is accelerated. 3. The turning state detecting means is means for detecting a combined acceleration of a lateral acceleration and a longitudinal acceleration of the vehicle body, and the second braking control means is adapted to start the braking operation from the start of the first operation. Only when the combined acceleration exceeds a predetermined level in the period until the control is started by the braking control means,
The automobile anti-skid device according to claim 1, which reduces or holds the braking pressure. 4. A braking control actuator for simultaneously controlling a braking pressure for a plurality of brake wheel cylinders provided for each wheel, a wheel speed detecting means for detecting a wheel speed for each wheel, and the wheel speed detection. Braking control means for controlling the braking pressure based on the wheel that shows the most locking tendency from the wheel speed information by the means, and rear inner wheel lift detection that detects the occurrence of lock of the rear inner wheel when the vehicle body turns Means, the braking control means, when the lock occurs due to the rear inner wheel floating detection means by the rear inner wheel floating,
An anti-skid device for an automobile, which controls a braking pressure based on wheel speed information of wheels other than the rear inner wheel. 5. The vehicle body speed as a reference for control is switched from the same all the wheels until then to the left and right independently when the lateral acceleration of the vehicle body exceeds a predetermined judgment level. Anti-skid device for automobiles.